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  • Pharmacodynamic Biomarker Characterization of ALX148, a CD47 … · 2021. 6. 8. · Pharmacodynamic...
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Pharmacodynamic Biomarker Characterization of ALX148, a CD47 Blocker, in Combination with Established Anticancer Antibodies in Patients with Advanced Malignancy Hong I Wan¹, Laura QM Chow², Justin Gainor³, Nehal Lakhani⁴, Hyun Chung⁵, Keun-Wook Lee⁶, Jeeyun Lee⁷, Patricia LoRusso⁸, Yung-Jue Bang⁹, Stephen Hodi 10 , Rafael Santana-Davila 11 , Wells Messersmith 12 , Philip Fanning¹, Pierre Squifflet¹, Feng Jin¹, Tracy Kuo¹, Sangeetha Bollini¹, Jaume Pons¹, Sophia Randolph¹ 1 ALX Oncology, Burlingame, CA, USA, and Dublin, Ireland; 2 Livestrong Cancer Institutes, Austin, TX, USA (current); 3 Massachusetts General Hospital Cancer Center, Boston, MA, USA; 4 START Midwest, Grand Rapids, MI, USA; 5 Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea; 6 Seoul National University Bundang Hospital, Seongnam, Korea; 7 Samsung Medical Center, Seoul, Korea; 8 Yale Cancer Center, New Haven, CT, USA; 9 Seoul National University Hospital, Seoul, Korea; 10 Dana Farber Cancer Center, Boston, MA, USA; 11 Seattle Cancer Care Alliance, Seattle, WA, USA 12 University of Colorado Cancer Center, Aurora, CO, USA. Background • CD47-SIRPα signaling is a myeloid checkpoint mechanism that signals the macrophage to ignore the cell on which CD47 is expressed. Tumors upregulate CD47 to evade the immune response. • ALX148 is a fusion protein with a high affinity CD47 blocker linked to an inactive human immunoglobulin Fc region (Figure 1). It blocks the CD47-mediated ‘don’t eat me’ signal and enhances anti-tumor immunity. 1 • AT148001, a first-in-human phase 1 study, evaluates ALX148 administered as a single agent (Part 1) and in combination with established anti-cancer antibodies (Part 2). 2-4 Figure 1. ALX148: A Unique High Affinity SIRPα Fusion Protein 1 High Affinity CD47 Binding Domains of SIRPα Inactive Fc Domain • Selectively binds CD47 to block its interaction with SIRPα with picomolar binding affinity • Fc domain mutated to eliminate Fcγ receptor binding • Molecular weight half the size of typical antibody • Fc domain enables antibody-like PK Figure 2. ALX148 Bridges Innate and Adaptive Immunity 1 1. SIRP Macrophage Fc Receptor Anti-Cancer Antibody CD47 ALX148 Tumor Antigen Cancer Cell α ALX148 Designed to Safely Maximize Anti-Cancer Antibody Activity 2. SIRPα CD47 ALX148 Macrophage M1 M1 M1 M2 Cancer Cell ALX148 Increases Ratio of Inflammatory M1 to Suppressive M2 in Tumor Microenvironment 3. TNFα ALX148 CD86 CCR7 MHC II IFNγ Cytotoxic Granules Dendritic Cell Cancer Cell CD8+ T Cell ALX148 Activates Dendritic Cells and Enhances Cross-Priming of T Cells Methods AT148001 Study Design • Part 1 (single agent): No MTD reached, maximum administered dose 30 mg/kg QoW 2 • Part 2 (combination): ALX148 (10 mg/kg QW) combined with standard regimens of pembrolizumab (200 mg IV Q3W) or trastuzumab (8 mg/kg IV → 6 mg/kg Q3W) Table 1. ALX148 Combination Solid Tumor Cohorts Combination Safety Confirmation ALX148 (10 mg/kg QW) + trastuzumab: Advanced malignancies (N=10) ALX148 (10 mg/kg QW) + pembrolizumab: Advanced malignancies (N=12) Combination Dose Expansion ALX148 + trastuzumab: HER2 positive Gastric/GEJ (N=20) progressed on prior fluoropyrimidine/trastuzumab ALX148 + pembrolizumab: HNSCC (N=20) progressed on prior platinum ALX148 + pembrolizumab: NSCLC (N=20) progressed on prior CPI and/or PD-L1<50% • Patients with HER2-positive advanced malignancy (n=30), including gastric/GEJ cancers progressed on or after trastuzumab therapy, received ALX148 + trastuzumab. Patients with advanced malignancy (n=52,) including HNSCC progressed on platinum-based chemotherapy, as well as NSCLC [progressed on prior checkpoint inhibitor (CPI) or tumor proportion score (TPS) <50%] received ALX148 + pembrolizumab. • Archival tumor tissue, on-treatment biopsies and whole blood samples were collected. CD8, CD68, CD163, PD-L1 and HER2 expression in tumor tissue were measured by immunohistochemistry (IHC) assays. Percent positive values for CD8, CD68 and CD163 were derived by image analysis. PD-L1 (Clone 22C3) TPS and combined positive score (CPS) were obtained by central pathologist review. HER2 levels were determined using HercepTest™. • RNA expressions from paired tumor biopsies were assessed using NanoString IO360 Panel. Cell type abundance and pathway profiling analyses using pre-defined gene signatures were performed using NanoString nSolver Analysis Software. • Peripheral CD47 Target Occupancy (TO) and immunophenotyping were measured by flow cytometry. Results Patient Baseline Characteristics • 82 patients with advanced solid tumor malignancies have been enrolled into Part 2 combination cohorts (Table 2). Table 2. Baseline Characteristics Pembrolizumab N=52 Trastuzumab N=30 Median Age, Years (range) 61 (32-81) 58 (45-79) Sex, n F 23 9 M 29 21 Race, n White 34 13 Black 3 1 Native American 1 – Asian 11 14 Other 3 2 ECOG PS, n 0 16 8 1 36 22 Primary Disease, n NSCLC 26 – HNSCC 20 – Gastric/GEJ/Esophageal – 25 Breast – 2 Colorectal 2 – Ovarian 2 1 Pancreatic – 1 Peritoneal 1 – Appendiceal 1 – Urothelial – 1 Note: Data Cutoff 18Apr2019. Clinical Results • ALX148 in combination with trastuzumab and pembrolizumab was well tolerated with no maximum tolerated dose reached. Treatment related adverse events (TRAE) were mostly of low grade and frequency and have been previously reported. 2-4 Figure 3. ALX148 + Trastuzumab Clinical Activity in HER2 positive Gastric/GEJ Cancer Expansion Cohort 100 80 60 40 20 0 -20 -40 -60 -80 -100 Change from Baseline (%) ORR: 21% (4/19) DCR: 26% (5/19) 2+ 2+ 0 1+ 2+ ND 2+ 3 2+ 0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score Note: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment. One patient with clinical progression not included in plots; ND = Not Done; HER2 Score retrospectively assessed using archival tissue by a central IHC lab. Figure 4. ALX148 + Pembrolizumab Clinical Activity in Advanced HNSCC Expansion Cohorts 60 40 20 0 -20 -40 -60 -80 53 5 5 0 65 80 5 5 25 0 1 2 20 35 0 40 23 15 0 CPS Change from Baseline (%) ORR: 20% (4/20) ALL, 40% (4/10) CPI Naive DCR: 30% (6/20) ALL, 40% (4/10) CPI Naive Checkpoint Inhibitor (CPI) Naive Prior Checkpoint Inhibitor Therapy Notes: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment; One patient with progressive disease not included in plots. Figure 5. ALX148 + Pembrolizumab Clinical Activity in Advanced NSCLC Expansion Cohort 50 40 30 20 10 0 -10 -20 -30 -40 0 0 0 0 0 0 ND 1 ND 0 0 7 0 1 ND 90 50 0 5 0 TPS (%) Change from Baseline (%) DCR: 15% (3/20) Checkpoint Inhibitor (CPI) Naive Prior Checkpoint Inhibitor Therapy Note: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment. Pharmacodynamic Results Figure 6. Complete CD47 Target Occupancy by ALX148 CD47 RO % Study Day 0 42 84 126 168 210 252 120 100 80 60 40 20 0 CD4 + T RBC CD47 RO % Days 0 42 84 126 168 210 252 120 100 80 60 40 20 0 ALX148 + Pembrolizumab (N=49) ALX148 + Trastuzumab (N=29) ALX148 + Pembrolizumab (N=50) ALX148 + Trastuzumab (N=30) Figure 7. No Changes of Circulating Immune Cell Profiles Following ALX148 Combinations Percentage Days CD4 + T% 0 56 28 84 112 140 168 196 80 60 40 20 0 Percentage Days CD8 + T% 0 56 28 84 112 140 168 196 50 40 30 20 10 0 Percentage Days CD19 + B% 0 56 28 84 112 140 168 196 40 30 20 10 0 Percentage Days CD16 + CD56 + NK% 0 56 28 84 112 140 168 196 40 30 20 10 0 ALX148 + Pembrolizumab (N=12) ALX148 + Trastuzumab (N=10) Figure 8. Increased Infiltrating Macrophages or Lymphocytes in Intratumoral Areas as Assessed by IHC Following ALX148 Combinations Percent Positive ALX148 Treatment Post ns Pre 30 20 10 0 Percent Positive ALX148 Treatment Post Pre 50 40 30 20 10 0 Percent Positive ALX148 Treatment Post Pre 30 20 10 0 Intratumoral CD8+ Cells Intratumoral CD68+ Cells Intratumoral CD163+ Cells ALX148 + Pembrolizumab ** * Percent Positive ALX148 Treatment Post ns ns Pre 30 20 10 0 Percent Positive ALX148 Treatment Post Pre 40 30 20 10 0 Percent Positive ALX148 Treatment Post Pre 30 20 10 0 Intratumoral CD8+ Cells Intratumoral CD68+ Cells Intratumoral CD163+ Cells ALX148 + Trastuzumab ** Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6) * p≤0.05 **p≤0.01 Target lesion change from baseline of -30% or greater decrease Target lesion change from baseline between -30% to +20% Target lesion change from baseline of +20% or greater increase Figure 9. Effects of ALX148 Combinations on Immune Cell Subsets in Tumor Biopsies As Assessed by RNA Expression Cell Type Score Centered Post Pre 0.4 0.2 0.0 -0.2 -0.4 Cell Type Score Centered Post Pre 0.6 0.4 0.2 0.0 -0.2 -0.4 Cell Type Score Centered Post Pre 0.6 0.4 0.2 0.0 -0.2 -0.4 Gastric/GEJ HNSCC NSCLC Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5) Cytotoxic cells DC Exhausted CD8 B-cells CD45 Macrophages Treg Neutrophils T-cells NK CD56dim cells Mast cells CD8 T cells NK cells Figure 10. Effects of ALX148 Combinations on Immune Pathways in Tumor Biopsies As Assessed by RNA Expression Signature Score Centered Post Pre 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 Signature Score Centered Post Pre 3 2 1 0 -1 -2 -3 Signature Score Centered Post Pre 4 2 0 -2 -4 Gastric/GEJ HNSCC NSCLC Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5) Antigen Presentation Cytokine and Chemokine Signaling Cytotoxicity IFNγ signaling Immune Cell Adhesion and Migration Interferon Signaling Lymphoid Compartment Myeloid Compartment Tumor inflmmation Immune Cell Localization to Tumors Myeloid Cell Activity NK Cell Activity T-Cell Priming and Activation Figure 11. IHC and RNA Expression Results from Patient 1 HNSCC PD-L1 (+) On-Treatment Biopsy (C3) Day 46 Cell Type Score Centered Post Pre 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 Signature Score Centered Post Pre 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 Change from Baseline (%) Time from Initiation of Treatment (days) 0 30 60 90 120 150 180 210 240 30 20 10 0 -10 -20 -30 -40 -50 Antigen Presentation Cytokine and Chemokine Signaling Cytotoxicity IFNγ Signaling Immune Cell Adhesion and Migration Interferon Signaling Myeloid Compartment Tumor Inflammation Pre-Treatment On-Treatment (C3) CD68 CD8 Cytotoxic Cells DC Exhausted CD8 B-cells CD45 Macrophages Treg Neutrophils T-cells NK CD56dim Cells Mast Cells CD8 T Cells NK cells Figure 12. IHC and RNA Expression Results from Patient 2 NSCLC PD-L1 (-) On-Treatment Biopsy (C3) Day 50 Cell Type Score Centered Post Pre 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 Signature Score Centered Post Pre 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 Change from Baseline (%) Time from Initiation of Treatment (days) 0 30 60 90 120 150 180 210 240 270 80 60 40 20 0 -20 -40 Antigen Presentation Cytokine and Chemokine Signaling Cytotoxicity IFNγ Signaling Immune Cell Adhesion and Migration Interferon Signaling Myeloid Compartment Tumor Inflammation Pre-Treatment On-Treatment (C3) CD68 CD8 Cytotoxic cells DC Exhausted CD8 B-cells CD45 Macrophages Neutrophils T-cells Mast cells CD8 T cells Figure 13. IHC and RNA Expression Results from Patient 3 Gastric Cancer HER2 (3+) On-Treatment Biopsy (C10) Day 188 Cell Type Score Centered Post Pre 2 1 0 -1 -2 Signature Score Centered Post Pre 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 Change from Baseline (%) Time from Initiation of Treatment (days) 0 25 50 75 100 125 150 175 200 225 60 40 20 0 -20 -40 -60 -80 -100 Antigen Presentation Cytokine and Chemokine Signaling Cytotoxicity IFNγ Signaling Immune Cell Adhesion and Migration Interferon Signaling Myeloid Compartment Tumor Inflammation Pre-Treatment On-Treatment (C10) CD163 CD8 Cytotoxic cells DC Exhausted CD8 B-cells CD45 Macrophages Neutrophils T-cells Mast cells CD8 T cells Note: Mast cells signature for this sample was determined based on a partial gene list. Conclusions Intended for combination, ALX148 is designed to block the CD47-SIRPa myeloid checkpoint pathway, safely maximizing innate and adaptive immune response to cancer. • ALX148 in combination with standard regimens of trastuzumab or pembrolizumab is well tolerated with a favorable hematologic safety profile. 2-4 • ALX148 demonstrates emerging anti-cancer activity that compares favorably with anticipated activity of trastuzumab alone in patients with advanced gastric/GEJ cancer that has progressed on prior HER2-targeted therapies; ALX148 also demonstrates emerging anti-cancer activity that compares favorably with single agent pembrolizumab in patients with HNSCC that has progressed on prior systemic therapy. • ALX148 at 10 mg/kg QW achieves complete CD47 target occupancy with no impact on circulating immune cells in combination with trastuzumab and pembrolizumab. • Assessment of tumor infiltrating immune cells and molecular signatures in paired tumor biopsies reveals differences in pharmacodynamic changes following different ALX148 combinations, providing insights to ALX148’s mechanism as a myeloid checkpoint inhibitor. Further studies are needed to confirm the relationship between pharmacodynamic changes and clinical responses. • ALX148 in combination with pembrolizumab showed increased immune infiltration of both innate and adaptive immune cells as well as increased inflammation signatures. • ALX148 in combination with trastuzumab showed increased macrophage infiltration without increased inflammation signatures. Patients in combination cohorts continue to be followed (NCT03013218). References 1. Kauder et al., ALX148 blocks CD47 and enhances innate and adaptive antitumor immunity with a favorable safety profile. PLOS ONE. 2018 13(8): e0201832. 2. Lakhani et al., A phase 1 study of ALX148, a CD47 blocker, alone and in combination with established anticancer antibodies in patients with advanced malignancy and non-Hodgkin lymphoma. Journal of Clinical Oncology 2018 36:15_suppl, 3068-3068. 3. Lakhani et al., A phase 1 study of ALX148: CD47 blockade in combination with anticancer antibodies to bridge innate and adaptive immune responses for advanced malignancy. Journal for ImmunoTherapy of Cancer 2018 6 (Suppl 1):114. Abstract 335. 4. Chow et al., A phase I study of ALX148, a CD47 blocker, in combination with established anticancer antibodies in patients with advanced malignancy. Journal of Clinical Oncology 2019 37:15_suppl, 2514-2514. Acknowledgments • We would like to thank all of the participating patients and their families as well as site research staff. • Contact email: [email protected] • Presented at the Society for Immunotherapy of Cancer (SITC) 34 th Annual Meeting, National Harbor, MD, USA, Nov. 6-10, 2019

Pharmacodynamic Biomarker Characterization of ALX148, a CD47 … · 2021. 6. 8. · Pharmacodynamic Biomarker Characterization of ALX148, a CD47 Blocker, in Combination with Established

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Page 1: Pharmacodynamic Biomarker Characterization of ALX148, a CD47 … · 2021. 6. 8. · Pharmacodynamic Biomarker Characterization of ALX148, a CD47 Blocker, in Combination with Established

Pharmacodynamic Biomarker Characterization of ALX148, a CD47 Blocker, in Combination with Established Anticancer Antibodies in Patients with Advanced Malignancy Hong I Wan¹, Laura QM Chow², Justin Gainor³, Nehal Lakhani⁴, Hyun Chung⁵, Keun-Wook Lee⁶, Jeeyun Lee⁷, Patricia LoRusso⁸, Yung-Jue Bang⁹, Stephen Hodi10, Rafael Santana-Davila11, Wells Messersmith12, Philip Fanning¹, Pierre Squifflet¹, Feng Jin¹, Tracy Kuo¹, Sangeetha Bollini¹, Jaume Pons¹, Sophia Randolph¹1ALX Oncology, Burlingame, CA, USA, and Dublin, Ireland; 2Livestrong Cancer Institutes, Austin, TX, USA (current); 3Massachusetts General Hospital Cancer Center, Boston, MA, USA; 4START Midwest, Grand Rapids, MI, USA; 5Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea; 6Seoul National University Bundang Hospital, Seongnam, Korea; 7Samsung Medical Center, Seoul, Korea; 8Yale Cancer Center, New Haven, CT, USA; 9Seoul National University Hospital, Seoul, Korea; 10Dana Farber Cancer Center, Boston, MA, USA; 11Seattle Cancer Care Alliance, Seattle, WA, USA 12University of Colorado Cancer Center, Aurora, CO, USA.

Background• CD47-SIRPα signaling is a myeloid checkpoint mechanism that signals the

macrophage to ignore the cell on which CD47 is expressed. Tumors upregulate CD47 to evade the immune response.

• ALX148 is a fusion protein with a high affinity CD47 blocker linked to an inactive human immunoglobulin Fc region (Figure 1). It blocks the CD47-mediated ‘don’t eat me’ signal and enhances anti-tumor immunity.1

• AT148001, a first-in-human phase 1 study, evaluates ALX148 administered as a single agent (Part 1) and in combination with established anti-cancer antibodies (Part 2).2-4

Figure 1. ALX148: A Unique High Affinity SIRPα Fusion Protein1

CD

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ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

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Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

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Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

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Antigen PresentationCytokine and Chemokine Signaling

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Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

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DCExhausted CD8

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Tumor Inflammation

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DCExhausted CD8B-cellsCD45

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Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

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8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

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α SIRP

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CD86

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DendriticCell

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High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

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ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

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2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

• Selectively binds CD47 to block its interaction with SIRPα with picomolar binding affinity

• Fc domain mutated to eliminate Fcγ receptor binding• Molecular weight half the size of typical antibody• Fc domain enables antibody-like PK

Figure 2. ALX148 Bridges Innate and Adaptive Immunity1

1.

CD

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0 5628 84 112 140 168 196

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0 5628 84 112 140 168 196

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0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

ALX148 Designed to Safely Maximize Anti-Cancer Antibody Activity

2.

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

ALX148 Increases Ratio of Inflammatory M1 to Suppressive M2 in Tumor Microenvironment

3.

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**C

ell T

ype

Scor

e C

ente

red

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

ALX148 Activates Dendritic Cells and Enhances Cross-Priming of T Cells

MethodsAT148001 Study Design

• Part 1 (single agent): No MTD reached, maximum administered dose 30 mg/kg QoW2

• Part 2 (combination): ALX148 (10 mg/kg QW) combined with standard regimens of pembrolizumab (200 mg IV Q3W) or trastuzumab (8 mg/kg IV → 6 mg/kg Q3W)

Table 1. ALX148 Combination Solid Tumor Cohorts

Combination Safety Confirmation

ALX148 (10 mg/kg QW) + trastuzumab:

Advanced malignancies (N=10)

ALX148 (10 mg/kg QW) + pembrolizumab:

Advanced malignancies (N=12)

Combination Dose Expansion

ALX148 + trastuzumab: HER2 positive Gastric/GEJ (N=20)

progressed on prior fluoropyrimidine/trastuzumab

ALX148 + pembrolizumab: HNSCC (N=20)progressed on prior platinum

ALX148 + pembrolizumab: NSCLC (N=20)progressed on prior CPI and/or PD-L1<50%

• Patients with HER2-positive advanced malignancy (n=30), including gastric/GEJ cancers progressed on or after trastuzumab therapy, received ALX148 + trastuzumab. Patients with advanced malignancy (n=52,) including HNSCC progressed on platinum-based chemotherapy, as well as NSCLC [progressed on prior checkpoint inhibitor (CPI) or tumor proportion score (TPS) <50%] received ALX148 + pembrolizumab.

• Archival tumor tissue, on-treatment biopsies and whole blood samples were collected. CD8, CD68, CD163, PD-L1 and HER2 expression in tumor tissue were measured by immunohistochemistry (IHC) assays. Percent positive values for CD8, CD68 and CD163 were derived by image analysis. PD-L1 (Clone 22C3) TPS and combined positive score (CPS) were obtained by central pathologist review. HER2 levels were determined using HercepTest™.

• RNA expressions from paired tumor biopsies were assessed using NanoString IO360 Panel. Cell type abundance and pathway profiling analyses using pre-defined gene signatures were performed using NanoString nSolver Analysis Software.

• Peripheral CD47 Target Occupancy (TO) and immunophenotyping were measured by flow cytometry.

ResultsPatient Baseline Characteristics• 82 patients with advanced solid tumor malignancies have been enrolled into Part 2

combination cohorts (Table 2).

Table 2. Baseline Characteristics

Pembrolizumab N=52

Trastuzumab N=30

Median Age, Years (range) 61 (32-81) 58 (45-79)Sex, n

F 23 9M 29 21

Race, nWhite 34 13Black 3 1Native American 1 –Asian 11 14Other 3 2

ECOG PS, n0 16 81 36 22

Primary Disease, nNSCLC 26 –HNSCC 20 –Gastric/GEJ/Esophageal – 25Breast – 2Colorectal 2 –Ovarian 2 1Pancreatic – 1Peritoneal 1 –Appendiceal 1 –Urothelial – 1

Note: Data Cutoff 18Apr2019.

Clinical Results• ALX148 in combination with trastuzumab and pembrolizumab was well tolerated with

no maximum tolerated dose reached. Treatment related adverse events (TRAE) were mostly of low grade and frequency and have been previously reported.2-4

Figure 3. ALX148 + Trastuzumab Clinical Activity in HER2 positive Gastric/GEJ Cancer Expansion Cohort

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Note: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment. One patient with clinical progression not included in plots; ND = Not Done; HER2 Score retrospectively assessed using archival tissue by a central IHC lab.

Figure 4. ALX148 + Pembrolizumab Clinical Activity in Advanced HNSCC Expansion Cohorts

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Notes: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment; One patient with progressive disease not included in plots.

Figure 5. ALX148 + Pembrolizumab Clinical Activity in Advanced NSCLC Expansion Cohort

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Note: Data Cutoff 23Sept2019. Patients who received at least one dose of ALX148 in the expansion phase, had a baseline assessment, and at least one post-baseline disease assessment.

Pharmacodynamic ResultsFigure 6. Complete CD47 Target Occupancy by ALX148

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 7. No Changes of Circulating Immune Cell Profiles Following ALX148 Combinations

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 8. Increased Infiltrating Macrophages or Lymphocytes in Intratumoral Areas as Assessed by IHC Following ALX148 Combinations

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 9. Effects of ALX148 Combinations on Immune Cell Subsets in Tumor Biopsies As Assessed by RNA Expression

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

dPostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 10. Effects of ALX148 Combinations on Immune Pathways in Tumor Biopsies As Assessed by RNA Expression

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 11. IHC and RNA Expression Results from Patient 1 HNSCC PD-L1 (+)

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 12. IHC and RNA Expression Results from Patient 2 NSCLC PD-L1 (-)

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Figure 13. IHC and RNA Expression Results from Patient 3 Gastric Cancer HER2 (3+)

CD

47 R

O %

Study Day0 42 84 126 168 210 252

120

100

80

60

40

20

0

Perc

enta

ge

Days

CD4+ T%

0 5628 84 112 140 168 196

80

60

40

20

0

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

50

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Perc

enta

ge

Days

CD8+ T%

CD4+ T RBC

0 5628 84 112 140 168 196

50

40

30

20

10

0

Perc

enta

ge

Days

CD19+ B%

0 5628 84 112 140 168 196

40

30

20

10

0

Perc

enta

ge

Days

CD16+CD56+ NK%

0 5628 84 112 140 168 196

40

30

20

10

0

CD

47 R

O %

Days0 42 84 126 168 210 252

120

100

80

60

40

20

0

ALX148 + Pembrolizumab (N=49)

ALX148 + Trastuzumab (N=29)ALX148 + Pembrolizumab (N=50)

ALX148 + Trastuzumab (N=30)

ALX148 + Pembrolizumab (N=12)ALX148 + Trastuzumab (N=10)

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Pembrolizumab

** *

Perc

ent P

ositi

ve

ALX148 TreatmentPost

ns ns

Pre

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

40

30

20

10

0

Perc

ent P

ositi

ve

ALX148 TreatmentPostPre

30

20

10

0

Intratumoral CD8+ CellsIntratumoral CD68+ Cells Intratumoral CD163+ Cells

ALX148 + Trastuzumab

**

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.4

0.2

0.0

-0.2

-0.4

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4 Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.6

0.4

0.2

0.0

-0.2

-0.4

Gastric/GEJHNSCC NSCLC

Paired biopsies (HNSCC n=5, NSCLC n=7, Ga/GEJ n=6)

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

* p≤0.05 **p≤0.01

Target lesion change from baseline of -30% or greater decrease

Target lesion change from baseline between -30% to +20%

Target lesion change from baseline of +20% or greater increase

Cytotoxic cells DCExhausted CD8

B-cellsCD45Macrophages

TregNeutrophils

T-cellsNK CD56dim cells

Mast cellsCD8 T cells

NK cells

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

3

2

1

0

-1

-2

-3

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

4

2

0

-2

-4

Gastric/GEJHNSCC NSCLC

On-TreatmentBiopsy (C3) Day 46

Paired biopsies (HNSCC n=5, NSCLC n=6, Ga/GEJ n=5)

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Antigen PresentationCytokine and Chemokine SignalingCytotoxicityIFNγ signalingImmune Cell Adhesion and Migration

Interferon SignalingLymphoid CompartmentMyeloid Compartment

Tumor inflmmation

Immune Cell Localization to Tumors

Myeloid Cell Activity

NK Cell Activity

T-Cell Priming and Activation

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240

30

20

10

0

-10

-20

-30

-40

-50

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic Cells

DCExhausted CD8

B-cells

CD45

Macrophages

TregNeutrophilsT-cellsNK CD56dim CellsMast CellsCD8 T Cells

NK cells

On-TreatmentBiopsy (C3) Day 50

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 30 60 90 120 150 180 210 240 270

80

60

40

20

0

-20

-40

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C3)

CD

68C

D8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

On-TreatmentBiopsy (C10) Day 188

Cel

l Typ

e Sc

ore

Cen

tere

d

PostPre

2

1

0

-1

-2

Sign

atur

e Sc

ore

Cen

tere

d

PostPre

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

Cha

nge

from

Bas

elin

e (%

)

Time from Initiation ofTreatment (days)

0 25 50 75 100 125 150 175 200 225

60

40

20

0

-20

-40

-60

-80

-100

Antigen PresentationCytokine and Chemokine Signaling

Cytotoxicity

IFNγ Signaling

Immune Cell Adhesion and MigrationInterferon SignalingMyeloid Compartment

Tumor Inflammation

Pre-Treatment On-Treatment (C10)

CD

163

CD

8

Cytotoxic cells

DCExhausted CD8B-cellsCD45

Macrophages

NeutrophilsT-cellsMast cellsCD8 T cells

SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CancerCell

CD8+T Cell

α SIRP

Macrophage

Fc Receptor

Anti-Cancer Antibody

Cancer Cell

CD47

ALX148

Tumor Antigen

SIRPα

CD47 ALX148

Macrophage

M1

M1 M1

M2

TNFα

ALX148

CD86

CCR7

MHC II

IFNγ

Cytotoxic Granules

DendriticCell

CancerCell

CancerCell

CD8+T Cell

α

High A�nity CD47 Binding Domains of SIRPα

InactiveFc Domain

100

80

60

40

20

0

-20

-40

-60

-80

-100

Cha

nge

from

Bas

elin

e (%

)

ORR: 21% (4/19) DCR: 26% (5/19)

80

60

40

20

0

-20

-40

-60

-80

53 5 5 0 65 80 5 5 25 0 1

2 20 35 0 40 23 15 0 CPS

Cha

nge

from

Bas

elin

e (%

)

ORR: 20% (4/20) ALL, 40% (4/10) CPI NaiveDCR: 30% (6/20) ALL, 40% (4/10) CPI Naive

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

50

40

30

20

10

0

-10

-20

-30

-40

0 0 0 0 0 0 ND 1 ND 0 0 7 0 1

ND 90 50 0 5 0 TPS (%)

Cha

nge

from

Bas

elin

e (%

)

DCR: 15% (3/20)

Checkpoint Inhibitor (CPI) NaivePrior Checkpoint Inhibitor Therapy

0 30 60 90 120 150 180 210 240

2+ 2+ 0 1+ 2+ ND 2+ 3 2+

0 3+ 2+ 3+ 2+ 3+ 3+ 1+ 3+ HER2 Score

Note: Mast cells signature for this sample was determined based on a partial gene list.

ConclusionsIntended for combination, ALX148 is designed to block the CD47-SIRPa myeloid checkpoint pathway, safely maximizing innate and adaptive immune response to cancer.

• ALX148 in combination with standard regimens of trastuzumab or pembrolizumab is well tolerated with a favorable hematologic safety profile.2-4

• ALX148 demonstrates emerging anti-cancer activity that compares favorably with anticipated activity of trastuzumab alone in patients with advanced gastric/GEJ cancer that has progressed on prior HER2-targeted therapies; ALX148 also demonstrates emerging anti-cancer activity that compares favorably with single agent pembrolizumab in patients with HNSCC that has progressed on prior systemic therapy.

• ALX148 at 10 mg/kg QW achieves complete CD47 target occupancy with no impact on circulating immune cells in combination with trastuzumab and pembrolizumab.

• Assessment of tumor infiltrating immune cells and molecular signatures in paired tumor biopsies reveals differences in pharmacodynamic changes following different ALX148 combinations, providing insights to ALX148’s mechanism as a myeloid checkpoint inhibitor. Further studies are needed to confirm the relationship between pharmacodynamic changes and clinical responses.• ALX148 in combination with pembrolizumab showed increased immune infiltration of both

innate and adaptive immune cells as well as increased inflammation signatures. • ALX148 in combination with trastuzumab showed increased macrophage infiltration

without increased inflammation signatures.

Patients in combination cohorts continue to be followed (NCT03013218).

References1. Kauder et al., ALX148 blocks CD47 and enhances innate and adaptive antitumor immunity with a

favorable safety profile. PLOS ONE. 2018 13(8): e0201832.2. Lakhani et al., A phase 1 study of ALX148, a CD47 blocker, alone and in combination with

established anticancer antibodies in patients with advanced malignancy and non-Hodgkin lymphoma. Journal of Clinical Oncology 2018 36:15_suppl, 3068-3068. 

3. Lakhani et al., A phase 1 study of ALX148: CD47 blockade in combination with anticancer antibodies to bridge innate and adaptive immune responses for advanced malignancy. Journal for ImmunoTherapy of Cancer 2018 6 (Suppl 1):114. Abstract 335.

4. Chow et al., A phase I study of ALX148, a CD47 blocker, in combination with established anticancer antibodies in patients with advanced malignancy. Journal of Clinical Oncology 2019 37:15_suppl, 2514-2514.

Acknowledgments• We would like to thank all of the participating patients and their families as well as site research staff.• Contact email: [email protected]• Presented at the Society for Immunotherapy of Cancer (SITC) 34th Annual Meeting,

National Harbor, MD, USA, Nov. 6-10, 2019

ASPEN-01: A Phase 1 Study of ALX148, a CD47 Blocker, in ......(EVAL) ORR (%) [95% CI] DOR (m) [95% CI] PFS (m) [95% CI] PFS Rate at 6 m OS (m) [95% CI] OS Rate at 12 m Follow Up (m)

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