Stemline Therapeutics, Inc.NASDAQ: STML

Corporate Overview

October 2016

Forward-Looking Statements

This presentation includes statements that are, or may be deemed, ‘‘forward-looking statements.’’ In some cases,

these forward-looking statements can be identified by the use of forward-looking terminology, including the terms

“believes,” “potentially,” “estimates,” “anticipates,” “expects,” “plans,” “intends,” “may,” “could,” “might,” “will,”

“should,” “approximately” or, in each case, their negative or other variations thereon or comparable terminology,

although not all forward-looking statements contain these words. They appear in a number of places throughout

this presentation and include statements regarding our intentions, beliefs, projections, outlook, analyses or current

expectations.

You should read carefully our “Special Cautionary Notice Regarding Forward-Looking Statements” and the factors

described in the “Risk Factors” sections of our reports on Form 10-K and Form 10-Q filed with the Securities and

Exchange Commission to better understand the risks and uncertainties inherent in our business.

2

Mission

To build a leading biopharmaceutical company focused on greatly

improving the lives of cancer patients by developing and

commercializing innovative oncology therapeutics.

3

Company Snapshot

4

Stock Symbol STML (Nasdaq)

Market Capitalization (9/30/16) $207 MM

Price (52 Week Range) $10.83 ($3.88 – $11.29)

Shares Outstanding 19.1 MM

Float 16.6 MM

Cash & cash equivalents (6/30/16) $81.2 MM

Top Holders (Institutional &

Management)

• Franklin Advisers

• Fidelity

• STML Management

• TimesSquare Capital

• Blackrock

• Baker Brothers

• Eventide

• Venrock

Analyst Coverage (Price target) • Ladenburg Thalmann ($41)

• H.C. Wainwright ($38)

• ROTH Capital ($32)

• Jefferies ($23)

• Wedbush ($15)

• Cowen (Pending)

IP Portfolio and Regulatory

Exclusivity

• 36 issued patents and over 45 pending

applications in the US and worldwide for

both in-licensed and internal inventions

• Orphan drug status for SL-401 (US &

Europe) and SL-701 (US)

Management Biographies

Ivan Bergstein, MD (CEO) - Dr. Bergstein is the Chief Executive

Officer and Founder of Stemline Therapeutics. Dr. Bergstein’s early and

broad intellectual property gives Stemline deep domain expertise in the

rapidly emerging cancer stem cell (CSC) field. He has guided the

company’s evolution from an early-stage R&D company to its present form

as a late clinical stage company with three clinical candidates. He received

a BA in mathematics from the University of Pennsylvania and was elected

to the Pi Mu Epsilon National Mathematics Honor Society, an MD from the

Mount Sinai School of Medicine where he was elected to the Alpha Omega

Alpha Honor Medical Society and received the Merck Award for Clinical

Excellence. Dr. Bergstein completed an internship in general surgery, and

an internal medicine residency and hematology-oncology fellowship at the

New York Presbyterian Hospital—Weill Medical College of Cornell

University.

Ken Hoberman (COO) - Mr. Hoberman has extensive financial,

accounting, investor relations, corporate governance and business

development experience including M&A, strategic alliances and

partnerships. His operational expertise includes regulatory oversight,

human resources, manufacturing and clinical development. He was

previously Vice President of Corporate and Business Development of

Keryx Biopharmaceuticals, where he initiated and executed a $100MM

strategic alliance and originated, negotiated and closed dozens of licensing

and operational contracts, helping to grow the market capitalization to over

$1 billion. He led the team that originated, in-licensed, and developed

Auryxia, was approved by the FDA. He serves on the Board of Directors of

TG Therapeutics (Nasdaq: TGTX). He received a B.S.B.A. in Finance from

Boston University and completed post-baccalaureate studies at Columbia

University.

Company Highlights

SL-401 – Targeted therapy directed to CD123

• Phase 2 registration trial in blastic plasmacytoid dendritic cell neoplasm (BPDCN)

- Breakthrough Therapy Designation granted by FDA in August 2016

- Oral presentations at ASCO 2016 and EHA 2016

- ORR >90% in first-line, ~50% in relapsed/refractory (R/R)

- Regulatory interactions ongoing; BLA preparation underway

• Phase 2 trials enrolling in additional CD123+ indications - Potential for significant market expansion

• AML in CR, MRD+

• R/R myeloproliferative neoplasms (mastocytosis, CMML, MF, eosinophilic sydrome)

• R/R multiple myeloma – in combination with POM+DEX

SL-801 – Novel, oral, small molecule, reversible inhibitor of Exportin-1 (XPO1)

• Phase 1 trial in advanced solid tumors; 4th cohort enrolling

SL-701 – Immunotherapy

• Phase 2 in adult second-line glioblastoma; Ongoing

5

Clinical Pipeline Overview

6

BPDCN = blastic plasmacytoid dendritic cell neoplasm; AML = acute myeloid leukemia; r/r = relapsed/refractory; CR = complete response; MRD = minimal residual disease;

MPN = myeloproliferative neoplasms; GBM = glioblastoma multiforme

Program Target Phase 2

SL-401

SL-701

IND

SL-801

BPDCN

IL-3R/CD123

IL-13Ra2

EphA2

Survivin

AML (in CR, MRD+)

MPN

Lead-in/dose escalation

XPO1

Advanced solid tumors

Adult GBM (2nd line)

Myeloma (r/r)

AML (r/r)

Enrolling

Enrolling

Advanced heme tumors

Enrolling

Enrolling

Enrolling

Enrolling

Enrolling

Planned

SL-401 - BPDCN

BPDCN Overview

8

BPDCN Skin Lesions

H&E

CD4 CD56 TCL1 CD123

BPDCN Bone Marrow

BPDCN

background

• Highly aggressive hematologic malignancy derived from

plasmacytoid dendritic cells (pDC) with poor prognosis

• Median OS ~12 months (range: 8-15) from diagnosis

Diagnosis • World Health Organization (WHO) formalized diagnostic criteria

(2008)

- CD4, CD56, CD123, TCL-1, other pDC markers

Presentation

and course

• Primary sites: skin and bone marrow

• Secondary sites: lymph nodes, other viscera, CNS

• Often rapidly degenerates with bone marrow failure

Unmet

medical need

• No approved therapies, standard of care or effective treatments

• Current recommendations are clinical trials for both first-line

and R/R BPDCN

Riaz et al. Cancer Control, 2014; Pagano et al. Haematologica, 2013

SL-401: Novel Targeted Therapy Directed

to the IL-3 Receptor (CD123)

9

CD123 overexpressed on BPDCN and many other

hematologic cancers

SL-401 is a targeted therapy directed to CD123

SL-401 is highly potent against BPDCN cells in vitro

and in vivo

In previous Phase 1/2 investigator-sponsored trial

(Blood, 2014), with only a single cycle of SL-401

• 78% (7/9) ORR: 5 CR, 2 PR

- 2 CR in first-line

o 1 alive at 33+ months

- 3 CR in relapsed/refractory

o 3 survived >12 months (including 1 who survived 30+ months)

% v

iab

le

SL-401 (fM)

BPDCN skin biopsy (IHC)

CD123

SL-401 fM IC50

against BPDCN cells

Truncated

diphtheria

toxin payloadIL-3

SL-401

IL-3R/CD123Cancer

cell

Trial Design and Eligibility Criteria (NCT02113982)

Lead-in (Stage 1) - Completed

• BPDCN and R/R AML

• SL-401 daily IV infusion for 5 days

• At 7, 9, 12, or 16 mg/kg/day for 5 doses

• Repeated every 21 days

Expansion (Stage 2) - Ongoing

• BPDCN

• SL-401 daily IV infusion for 5 days

• At maximum tested Stage 1 dose

(12 mg/kg/day); MTD in BPDCN not reached

• Repeated every 21 days

Select inclusion criteria

• BPDCN: first-line or R/R (Stages 1 and 2)

• AML: R/R (Stage 1)

• Age ≥ 18; ECOG PS 0-2

• Adequate organ function including: LVEF ≥ LLN, creatinine ≤ 1.5mg/dL, albumin ≥ 3.2 g/dL,

bilirubin ≤ 1.5 mg/dL, AST/ALT ≤ 2.5x ULN

10

MTD = maximum tolerated dose

11

Most Common Adverse Events (≥ 15% treatment-related adverse effects, TRAEs )

All Grades (%) Grade ≥ 3 (%)

TRAEs All AEs TRAEs All AEs

Transaminase elevation 61 74 57 61

Hypoalbuminemia 43 48 0 0

Chills 35 39 0 0

Pyrexia 30 48 0 0

Nausea 26 52 0 0

Fatigue 26 43 0 9

Thrombocytopenia 22 22 22 22

Hypotension 22 22 0 0

Weight increased 22 30 0 0

Capillary leak syndrome (CLS)2 22 22 9 9

Anemia 17 30 13 17

Decreased appetite 17 22 0 0

Edema peripheral 17 43 0 0

SL-401 Adverse Events1

1As of July 2016 2Two Stage 1 patients had Grade >2 CLS: Grade 5 (7 mg/kg) and Grade 4 (12 mg/kg).

No Stage 2 BPDCN patients had Grade >2 CLS

• Most common side effects were transient

transaminase elevation and hypoalbuminemia;

not dose limiting

• Since implementation of safety precautions in

lead-in (Stage 1), severe CLS not observed in

BPDCN

• No dose reductions required in any patients to

date, including middle-aged/elderly

• No cumulative side effects with multiple cycles

• Data, to date, indicate that SL-401 is more

tolerable, especially in middle-aged/elderly, than

combination chemotherapy previously used in

BPDCN

12

SL-401: Summary of Clinical Activity1

High response rates

• 86% (18/21) ORR in BPDCN (all lines/all doses)

• 100% (14/14) ORR in first-line BPDCN (all doses)

• 92% (11/12) CR/CRc rate in first-line BPDCN (12 ug/kg)

• >50% (4/7) ORR in R/R; 1 CRc

Response duration data maturing, promising

• 75% (9/12) first-line (12 ug/kg) progression-free (3+-16+ mo)

- 4 receiving SL-401 therapy (3+-12+ mos; 1+-16+ cycles)

- 5 bridged to SCT; remain in remission (3+-16+ mo)

• 1 R/R CRc patient bridged to SCT

• PFS and OS trending favorably

Further clinical updates later this year

1As of July 2016; does not include 3 pediatric patients treated under compassionate use

13

Line of Therapy All lines First-line First-lineRelapsed/

Refractory

Dose Group All Doses All Doses 12 ug/kg 12 ug/kg

n (total) 26 16 13 10

n (evaluable) 21 14 12 7

ORR 86% 100% 100% 57%

CR/CRc,

n (rate)13 (62%) 12 (86%) 11 (92%) 1 (14%)2

PR 5 2 1 3

SCT, n

(autoSCT n=3;

alloSCT n=3)

6 5 5 1

SL-401: Summary of Clinical Activity1

Abbreviations:

• ORR = overall response rate

• CR = complete response

• CRc = clinical complete

response - CR in non-skin

organs with gross reduction in

cutaneous lesions and residual

microscopic skin disease

• PR = partial response

• SCT = stem cell transplant

1As of July 2016; does not include 3 pediatric patients treated under compassionate use2Does not include 1 PR with bone marrow CR

Bone Marrow Responses1

14

Bone marrow blast count best responses with SL-401

for all evaluable BPDCN patients

with blast counts > 5% at screening (n=10)

Ab

so

lute

% b

las

ts

0%

10%

20%

30%

40%

50%

60%

Screening Best response

First-line

R/R

Pretreatment Post-cycle 2

H&

EIH

C (

CD

56

)

• 62 year old female with extensive BPDCN involving skin, bone

marrow, lymph nodes, viscera (spleen, eyelids, gums)

• Received 4 cycles of SL-401 and achieved a CR

• Bone marrow biopsy (pretreatment and end of cycle 2) shows

clearance of CD56+ BPDCN cells

Representative bone marrow response

1As of July 2016

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Best Response and Treatment Duration for

All BPDCN Patients (n=29)1

Relapsed/refractory (12 mg/kg/day SL-401)

First-line (12 mg/kg/day SL-401)

First-line (7 mg/kg/day SL-401)

Bridged to stem cell transplant (SCT)

Discontinued, disease recurrence

Discontinued, not specified

Discontinued, disease progression

Discontinued, AE

Lost to follow-up

Assessment pending

Compassionate use

a

b

c

d

LTFU

AP

CU

* auto-SCT

** allo-SCT

CRCRCRc

CR

CRc

CRCR

CRCRCRc

CRCRcPRPRCR

PR

PR

PR

Months

*

**

**

**

**

Ongoing

OngoingOngoing

OngoingOngoing

Ongoing

Ongoing

Ongoing

OngoingOngoing

Ongoing, AP

Ongoing, AP

Ongoing, AP

Ongoing, APOngoing, AP

a

b

a

a

a

b

a

c

LTFU

d

c

c

b

Pediatric/CU, first-line (12 mg/kg/day SL-401)

Pediatric/CU, relapsed/refractory (12 mg/kg/day SL-401)

Ind

ivid

ua

l p

ati

en

ts

PR (bone marrow CR)

1As of July 201615

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Best Response and Treatment Duration for

First-line BPDCN Patients Treated at 12 mg/kg/day (n=14)1

CR

Months

CR

CRc

CR

CR

CR

CRc

CR

CR

CRc

PR

CR

*

*

*

**

**

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing

Ongoing, AP

Ongoing, AP

a

b

a

First-line (12 mg/kg/day SL-401)

Bridged to stem cell transplant (SCT)

Discontinued, disease recurrence

Discontinued, not specified

Assessment pending

Compassionate use

a

b

AP

CU

* auto-SCT

** allo-SCT

Pediatric/CU, first-line (12 mg/kg/day SL-401)

Ind

ivid

ua

l p

ati

en

ts

1As of July 201616

Progression Free SurvivalN=13

1L BPDCN [12 ug/day]

PFS (months)

0 2 4 6 8 10 12 14 16 18

PF

S P

rob

ab

ility

0.00

0.25

0.50

0.75

1.00

Overall SurvivalN=13

1L BPDCN [12 ug/day]

Survival Time (months)

0 2 4 6 8 10 12 14 16 18

Su

rviv

al P

roba

bility

0.00

0.25

0.50

0.75

1.00

PFS and OS in First-line BPDCN (12 mg/kg/day SL-401)1

17

Progression-Free Survival

(n=13)Overall Survival

(n=13)

1As of July 2016

SL-401 Next Steps and Milestones

18

BLA preparation underway in BPDCN

• Breakthrough Therapy Designation (BTD) granted by FDA in BPDCN in August 2016

• Regulatory interactions ongoing

• Investing in key infrastructure to support BLA filing

Creating foundation for commercialization

• Launched disease awareness campaign

• Ramping up pre-commercial activities

Pursuing multiple market expansion opportunities

• Trials in additional CD123+ malignancies (e.g. AML, MPN, myeloma); Enrolling

• SL-401 both as a single agent and combination; Enrolling

• Potential in other CD123+ pDC-mediated diseases (e.g. autoimmune); Planning

SL-401 Market Expansion Opportunities

(AML, MPN, Myeloma)

AML in CR, MRD+ Trial

20

Stage 1 (Lead-in) - Completed

• AML in CR

• 9 patients

• 7, 9, or 12 mg/kg/day for 5 days, every 4

weeks

• ~15 sites in North America

Updates expected

2H16

Stage 2 (Expansion) - Enrolling

• AML in CR, MRD+

• ~15-20 patients

• At dose defined by Stage 1 (12 mg/kg/day)

• Endpoints

- Decrease in MRD burden

- CR durability

• Relapse rates unacceptably high in acute myeloid leukemia (AML)

• Microscopic leukemia cells left behind after chemotherapy (minimal residual disease; MRD)

• MRD is CD123+

• SL-401 employed to eliminate MRD and potentially improve outcomes

MPN Trial

21

• AML in CR

• ~9-12 patients

• 7, 9, or 12 ug/kg/day for 5 days,

every 4 weeks

• ~15 sites in North America

Stage 1 (Lead-in) - Enrolling

• 4 types of high-risk MPN*

• ~9-12 patients

• 7, 9, or 12 mg/kg/day for 3 days, every 3

weeks

• 10-15 sites in North America

Updates expected

2H16

* 4 types of high-risk myeloproliferative neoplasms (MPN)

• Mastocytosis

• Eosinophilic syndrome

• Myelofibrosis

• Chronic myelomonocytic leukemia (CMML)

Stage 2 (Expansion)

• 4 types of high-risk MPN

- 4 arms (1 arm for each indication)

• ~15-20 patients each arm, with expansion

flexibility (Simon 2-stage)

• At dose defined by Stage 1

• Endpoints: ORR, CR, response duration

• Many myeloproliferative neoplasms (MPN) are CD123+

• Similar to BPDCN, SL-401 employed to directly target these malignancies

22

• AML in CR, MRD+

• ~15-20 patients

• At dose defined by Stage 1

• Endpoints

- MRD+ to MRD- conversion

- CR durability

• AML in CR

• ~9-12 patients

• 7, 9, or 12 ug/kg/day for 5 days,

every 4 weeks

• ~15 sites in North America

Stage 1 (Lead-in) - Enrolling

• (r/r) myeloma (2+ prior therapies)

• ~12-18 patients

• SL-401 (7, 9, or 12 mg/kg/day for 5 days)

every 4 weeks

- Cycle 1: SL-401

- Cycles 2+: SL-401 + pomalidomide

(POM) and dexamethasone (DEX)

• ~5 sites in North America

Stage 2 (Expansion)

• (r/r) myeloma (2+ prior therapies)

• 14 patients

• At dose defined by Stage 1

• Endpoints: ORR, clinical benefit rate,

response duration, PFS and OS

Myeloma Trial: SL-401 + Pomalidomide

• First combination study for SL-401

• Despite some successes, myeloma remains largely incurable disease

• Certain abnormal bone marrow cells in myeloma are CD123+

• SL-401 employed to directly target these cells

SL-801

SL-801 Overview

24

1. XPO1 recognizes cargo proteins through nuclear

export sequences and bind cargos in nucleus.

2. Ternary complex transported through nuclear pore

complex and into cytoplasm where cargo released.

3. XPO1 and Ran subsequently recycled into nucleus

where process is repeated.

SL-801 Background

• Orally administered, novel small molecule inhibitor of XPO1 (Exportin 1)

Clinically-Validated Mechanism of Action / Potential for

Differentiation

• XPO1 is a key nuclear transport oncogene

• Clinically-validated target in multiple cancer types

• SL-801 reversibly inhibits XPO1 in low nanomolar range; may

offer improved therapeutic window benefits

Status – Phase 1 Enrolling Patients

• Phase 1 trial advanced solid tumors underway; Enrolling 4th cohort

• Phase 1 trial in advanced hematologic cancers planned

Strong IP Protection

• Composition of matter patent to 2030

SL-801: Reversible and Potent XPO1 Inhibitor

25

SL-801 is a reversible inhibitor of XPO1

Sakakibara, Blood, 2011; ASH 2015

SL-801 has potent in vitro activity against

multiple solid and hematologic cancers

XPO1

Biotin

XPO1

Actin

100nM

SL-801-biotin

0.5nM

Leptomycin-biotin

0.001

0.01

0.1

1

GI 5

0(m

M)

SL-801: Anti-Tumor Activity in Animal Models

26

0

200

400

600

800

1000

1200

1 8 15 22 29 36 43 50 54 61 66 73

NCI-H226 non-small cell lung cancer

0

1000

2000

3000

4000

5000

6000

1 5 10 15 19 24 29 33 38 43 47 52 57

22RV prostate carcinoma

Tu

mo

r vo

lum

e (

mm

3)

Days after first treatment

Vehicle, qd (d1-5,8-12,15-19)

SL-801, 31.25 mg/kg, qd (d1-5,8-12,15-19)

SL-801, 125 mg/kg, qd (d1,3,5,8,10,12,15,17,19)

Vehicle, qd (d1,3,5,8,10,12,15,17,19)

SL-801, 125 mg/kg, qd (d1,3,5,8,10,12,15,17,19)

SL-801, 125 mg/kg, qd (d1,8,15)

SL-801, 250 mg/kg, qd (d1,8,15)

*

***

***

***

*** 0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250 300 350

MM.1S multiple myeloma

Vehicle, qd (d1,3,5,8,10,12)

SL-801, 125 mg/kg, qd (d1,3,5,8,10,12)

SL-801, 125 mg/kg, qd (d1,8,15)

Su

rviv

al

rate

(%

)

***

Days after first treatment Days after first treatment

Tu

mo

r vo

lum

e (

mm

3)

*, p < 0.05; **, p < 0.01; ***, p < 0.001

SL-801 demonstrates potent anti-tumor activity in animal models, across wide array of solid and hematologic cancers

27

• AML in CR, MRD+

• ~15-20 patients

• At dose defined by Stage 1

• Endpoints

- MRD+ to MRD- conversion

- CR durability

• AML in CR

• ~9-12 patients

• 7, 9, or 12 ug/kg/day for 5 days,

every 4 weeks

• ~15 sites in North America

Multicenter, Dose Escalation (Standard 3+3 design)

• Advanced solid tumors

• 40-50 patients with advanced solid tumors

• Dose escalation: starting at 5 mg oral tablet/day

- 4 days on/3 days off x 2 weeks (for 21 day cycle)

• Evaluate safety

• Signal detection for subsequent Phase 2 disease-directed trials

• Endpoints

- Safety, maximum tolerated dose (MTD) determination

- ORR, disease control, duration of response, PFS, OS

• 5 sites in U.S.

Phase 1 in advanced solid tumors underway – Fourth dosing cohort open

Updates expected

2H16

Phase 1 in advanced hematologic cancers planned

SL-801 – Clinical Development Plan

SL-701

SL-701 Background

29

Immunotherapy designed to elicit anti-tumor

immune response

• Off-the-shelf, subcutaneously-administered peptides

• Immune response against targets overexpressed on

GBM - IL-13Rα2, EphA2, Survivin

3 Phase 1/2 investigator-sponsored trials with earlier

version (~70 patients)

• Adults and children with high grade gliomas

• Adjuvant: poly-ICLC, a toll-like receptor 3 agonist

• Multiple major objective responses in adults and

children

Phase 2 trial in adult second-line GBM - Ongoing

• Stage 1 (completed): SL-701 + adjuvants (GM-CSF

and Imiquimod) - Patients continue to be followed

• Stage 2 (enrolling): SL-701 + adjuvant (poly-ICLC)

+ bevacizumab - Patients currently enrolling

• Trial updates expected this year

Orphan drug designation in glioma

Reactive gliosis Numerous

CD68+ macrophages

Abundant CD8+

T cells

• Inflammatory response, including abundant cytotoxic (CD8+) T cells,

in region of brain tumor in setting of regression post-therapy

Pre-therapy (baseline)Nine weeks post-therapy

shows tumor shrinkage

Post-therapy brain biopsy

Financial Summary

Financial Summary

31

As of June 30th, 2016

Cash, Cash Equivalents and Investments (mm) $81.2

Debt $0.0

Shares Outstanding (mm) 19.1

Milestones

Stemline Key Events and Milestones

33

Program Event Timing

SL-401 Oral presentation of BPDCN clinical data at ASCO ✔ June 2016

SL-401 Oral presentation of BPDCN clinical data at EHA ✔ June 2016

SL-401 BTD in BPDCN granted by FDA ✔ August 2016

SL-701 Phase 2 clinical updates at SNO November 2016

SL-401 FDA meeting to discuss BPDCN regulatory requirements November/December 2016

SL-401 Phase 2 clinical updates at ASH on BPDCN trial December 2016

SL-401 Phase 2 clinical updates at ASH on other indications December 2016

SL-801 Phase 1 clinical updates 1H17

Stemline Therapeutics, Inc.NASDAQ: STML

Corporate Overview

October 2016