Ospedale Amedeo di Savoia

Ospedale Amedeo di Savoia

Giovanni Di Perri

CLINICA DI MALATTIE INFETTIVE

Università degli Studi di Torino

FARMACOLOGIA CLINICA DELLA TERAPIA ANTIRETROVIRALE

Antiretroviral Drug Approval: 1987-2009

MaravirocRaltegravirEtravirine

Darunavir

Tipranavir

EnfuvirtideAtazanavirEmtricitabineFosamprenavir

Tenofovir

Lopinavir/r

Amprenavir

EfavirenzAbacavir

NelfinavirDelavirdine

RitonavirIndinavirNevirapine

3TCSaquinavir

d4TddCddl

AZT

• NRTI, Nucleoside reverse transcriptase inhibitor;• NNRTI, Non-nucleoside reverse transcriptase inhibitor;• PI, protease inhibitor• Integrase Inhibitor• CCR5 Antagonist/Entry Inhibitor

HIV CYCLEHIV CYCLE

BINDING

UNCOATING

REVERSETRANSCRIPTION

INTEGRATION

TRANSCRIPTION

TRANSLATION

ASSEMBLY

PROTEASE

genomic RNA

double strandedDNA

genomic RNA

viral proteins

cellmembrane

cell nucleus

proviral RNA

viral mRNA

ProteaseInhibitors

BUDDING

CD4

CCR5 CXCR4

RT InhibitorsN/tRTIsNNRTIs

Fusion inhibitors

co-receptors inhibitors

integrase inhibitors

mwg/mol

OralBioav.

%

VD Protein binding

%

Plasma T/2h

IC PPP T/2

h

Elimination(major route)

AZT 267.24 64 1.6 + 0.6 L/Kg

< 25 0.5 - 3 7

d4T 224.2 86.4 +18.2

46 + 21 < 5 1.6 + 0.23

7

ddI 236.2 42 + 12 1.08 + 0.22 L/Kg

< 5 1.5 24

TDF 635.52 25 1.3 + 0.6 L/Kg

0.7–7.2 17 150

3TC 229.3 86 + 16 1.3 + 0.4 L/Kg

< 36 5 - 7 25

FTC 247.24 93 1.4 + 0.3 L/Kg

< 4 10 39

ABV 670.76 83 0.86 + 0.15 L/Kg

50 1.5 + 0.63

20

N/NtRTIs: basic pharmacologic features

N/NtRTIs:New drugs under development

• Abacavir ABC• Didanosine DDI• Emtricitabine FTC• Lamivudine 3TC• Stavudine D4T• Zidovudine ZDV• Zalcitabine DDC• Tenofovir TDF

-apricitabine-Amdoxovir- GS 9131 (9148)- Racivir- Elvucitabine

(?)

Peso mol.

g/mol

Biod.Orale

(%)

VD Legame Proteico

(%)

Plasma T/2(h)

Eliminazione(via principale)

EFV 315.68 nd 2.4 L/Kg > 99 45

NVP 266.3 93 1.21 L/Kg 60 25-30

ETR 435.28 nd nd 99.9 41

NNRTIs: caratteristiche farmacologiche

NNRTIs:New drugs under development

• Delavirdine DLV• Efavirenz EFV• Nevirapine NVP• Etravirine ETR

- TMC 278 (rilpivirine)- UK- 453,061 (Lersivirine)- IDX 899- RDEA 806

Drug

Efavirenz

Nevirapine

Etravirine

Cmin (ng/mL) Efficacy

** 1000-2200-3000*

3400-4300

- *

Cmin (ng/mL) Toxicity

** 4000

6000

-

* after NVP failure * pending results in nive patients with the 100 mg tablet

Reference Concentrations (Cmin) for Efficacy & Toxicity

• 154 HIV-infected patients– All taking 3-drug ART– HIV RNA in blood <50 c/mL

• HIV RNA measured using a more sensitive assay (2.5 c/mL)

– NVP: 60% <2.5 c/mL– EFV: 42% <2.5 c/mL– LPV/r: 29% <2.5 c/mL

• NVP was the only factor associated with undetectable HIV RNA on multivariate analysis

Bonora et al. J Med Virol 2009;81:400–405

0

50

40

30

20

10

NVP EFV LPV/r

HIV

RN

A (c

opie

s/m

L)

p<0.05

n 48 57 49

p<0.05

Ultrasensitive Assessment of Residual HIV Viraemia in HAART-Treated Patients With Persistently Undetectable Plasma HIV-RNA: A Cross-

Sectional Evaluation

Peso mol.g/mol

Biod. Orale (%)

VD Legame Proteico

(%)

Plasma T/2 (h)

Eliminazione(Via

principale)

APV 625.7 nd 6 L/Kg 90 7.7

IDV 711.8 65 0.4-1.7 L/Kg 60 2.0

LPV 628.8 nd nd 98-99 5-6

NFV 663.90 70-80 2-7 L/Kg > 98 3.5-5

RTV 720.95 nd 0.3-0.6 L/Kg 97 3-5

SQV 766.95 4 700 L 97 7-12

ATV 704.9 68 nd 86 8.6

TPV 602.7 nd nd > 99.9 5.5-6.0

DRV 547.7 37-82 88.1-131 L 95 15

PIs: caratteristiche farmacologiche

PIs:New drugs under development• Amprenavir

APV• Indinavir IDV• Lopinavir LPV• Nelfinavir NFV• Ritonavir RTV• Saquinavir SQV• Atazanavir ATV• FosAmprenavir fAPV• Tipranavir TPV• Darunavir DRV

- GS 8374- GRL 98065

Drug

Amprenavir

Indinavir

Lopinavir/Ritonavir

Nelfinavir

Ritonavir

Saquinavir

Atazanavir

Tipranavir


400

100

1000

*800

2100

100-250

150

15000 - 20000 #


-

8000-10000

-

-

2100

-

850

35000

* M8; ** Measured 8-20 hours post-dose # in case of triple drug failure


DRUG + TARGET DRUG/TARGET

Keq

DRUG + TARGET DRUG/TARGETKeq

In case of reduced target affinity (by selection of mutations in the PI genome coding for PI-resistance), the same effect may be obtained by increasing drug exposure

[c] ng/mL

1 2 3 4 5 6 n. PI mutations

11000

10000

9000

8000

7000

6000

5000

4000

3000

2000

1000

Median [c]

WT MEC

R1 MEC

R2 MEC

R3 MEC

R4 MEC

R5 MEC

R6 MEC

?

Rn

Rn MEC

How far the proportionality between the n. of PI resistance mutations and the value of MEC is maintained?

Antiretrovirals disposition is complex Intracellualr and plasma concentrations of antiretrovirals are influenced by many processes that are mediated by different transporters and enzymes.

ABCB1

TransportersABCC1ABCC2OATPs

CYP3A4

MetabolismCYP3A5CYP2B6

CYP2C19PXR

Nuclear ReceptorsCAR

PXR

CYP3A

DrugATP ADP + Pi

ABCB1

DrugATP ADP + Pi

ABCC1

Pregnane X receptor

Favourable genotypes

rho = 0.517, p = 0.0001

n = 13 n = 15 n = 24 n = 3

Number of favourable genotypes

850

150

ATV 400 QD

ATV 200 bid

Bonora S, et al. Abstr O 17Unboosted – Atazanavir (ATV) (3) ATV ng/mL

0

1200

1000

800

600

400

200

[Ctrough] gm

Below MEC (150 ng/ml)

ATV QD 6/10 pts

ATV bid

2/10 pts

plasma

ATV 400 QD

ATV 200 bid

465

745

Intracellular(PBMCs)

Peso mol.

g/mol

Biod.Orale

(%)

VD Legame Proteico

(%)

Plasma T/2(h)


ENF 4491.9 84.3* 5.5 L 92 3.8 Protein catabolism

MVC 51.3.7 23 194 L 76 13.2

EIs: caratteristiche farmacologiche

lucgag polenv

gag pol

CD4 CCR5

R5X4R5/X4 (dual)

lucgag polenv

gag pol

Luciferase expression vector

Env expressionvector library

Transfection

Infection

CD4 CXCR4Entry inhibitors added for confirmation of tropism call

Entry Inhibitors:

New drugs under development

• Enfuvirtide T-20

• Maraviroc MVC

-Vicriviroc-PRO 140-INCB009471-AMD 070-TNX-355

HIV Attachment, Co-receptor Binding, and Fusion Targets for Inhibition

Co-receptorBinding

CCR5/CXCR4(R5/X4)

CCR5 antagonistse.g. maraviroc,vicriviroc, PRO 140

Virus–CellFusion

Fusion inhibitorse.g. enfuvirtidegp41

gp120

V3 loop

CD4Binding

CD4

Cellmembrane

CD4 bindinginhibitorse.g. TNX-355

Adapted from Moore JP, et al. Proc Natl Acad Sci USA 2003;100:10598–10602

Drug

Enfuvirtide

Maraviroc


1500-1900

100


-

400


0

Analysis of MERIT study[1]

WeeksMed

ian

CD4+

Cel

l Cou

nt Δ

Fro

m B

asel

ine

(cel

ls/m

m3 )

50

100

150

0 16 32 482 8 12 24 4020

MVC + ZDV/3TC (n = 360)

EFV + ZDV/3TC (n = 360)

151

122

P = .004 for the difference over time

4

+ 8.1%

+ 9.5%

Δ CD4+ Percentage Bonora S, et al. ICAAC 2009

Maraviroc PK is influenced by OATP1B1

OATP1B1 is a major hepatic influx transporter and its substrate specificity for MVC has been investigated.

OATP1B1 521CT correlates with higher MVC plasma concentrations, confirming the role of OATP1B1 in the disposition of MVC.

Siccardi M, et al. IWCPHT 2009

Siccardi M, et al. CROI 2010

Peso mol.

g/mol

Biod.Orale

(%)

VD Legame Proteico

(%)

Plasma T/2(h)


RAL 482.51 32 nd 83 9.0

IIs: caratteristiche farmacologiche

Integrase Inhibitors:• Raltegravir

New drugs under development

- elvitegravir- GSK 1349572

RAL efficacy is not driven by Cmin

• 16 out of 332 patients had GM observed C12hr values <33 nM (~in vitro IC95)

• These patients had a similar rate of treatment success compared to patients with other GM observed C12hr values

GM Observed C12hr (nM)

8 - 128 - 254 - 547 -

% o

f P

atie

nts

with

HIV

RN

A <

400

0

20

40

60

80

100

125 254 545 9151

GM Observed C12hr (nM)

8 - 128 - 254 - 547 -

% o

f Pat

ient

s w

ith H

IV R

NA

<40

0

0

20

40

60

80

100

125 254 545 9151

GM Observed C12hr <33 nM

Wenning et al HIV Clin Pharm Workshop 2008

Outcomes at Week 48

9785

9890 8785 83

88 88 87

0

20

40

60

80

100

120

100 mg 200 mg 300 mg 400mg EFV

<400 copies <50 copies

Virologic Efficacy

Raltegravir

CD4+ count increases similar between arms: 144-221 cells/mm3

Markowitz 2007

S/GSK1349572: Potent Virologic Suppression in 10-Day Monotherapy Study

• 10-day monotherapy study in HIV-infected patients evaluated efficacy of varying doses of S/GSK1349572[1]

– Mean maximal reduction in HIV-1 RNA during study period

• -2.5 log10 copies/mL in 50-mg dose arm

• Resistance profile distinct from that of RAL and ELV[2]

• 12-hr half-life allows QD dosing[3]

• Activity not dependent on boosting[3]

1. Lalezari J, et al. IAS 2009. Abstract TUAB105. Reproduced with permission. 2. Underwood M, et al. IAS 2009. Abstract WEPEA098. 3. Min S, et al. IAS 2009. Abstract WEPEA099.

Dosing period Follow-up period

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1(BL)

2 3 4 7 8 91011 14 21(FU)Day

Mea

n Ch

ange

Fro

m B

asel

ine

in

HIV

-1 R

NA

(log 10

c/m

L)

2 mg10 mg50 mgPBO

Mapping the RAL inhibition window

0

500

1000

1500

2000

2500

0 10 20 30 40 50

Time of RAL addition or removal (h)

Infe

cted

cel

ls/w

ell

RAL washed outat different times

RAL added atdifferent times

RAL Inhibition Window: ~4h – 12h post-infection

Persistent RAL inhibitory effect

Raltegravir Exhibits a Long Off-Rate on Complexes Assembled in vitro

T1/2 = 27 hrs at room temp

Time (min)

0 500 1000 1500 2000 2500

Frac

tion

boun

d

0.0

0.2

0.4

0.6

0.8

1.0

WT - ralN155H - ral

Letter Nature Medicine 14, 762 - 766 (2008) Published online: 15 June 2008

Dose-response curve slope sets class-specific limits on inhibitory potential of anti-HIV drugs

Lin Shen, Susan Peterson, Ahmad R Sedaghat, Moira A McMahon, Marc Callender, Haili Zhang, Yan Zhou, Eleanor Pitt, Karen S Anderson, Edward P Acosta & Robert F Siliciano

In ARVs pharmacology it is common to refer to drug potency in terms of Inhibitory quotient (IQ) LPV [c] ng/mL

WT MEC for LPV [c] ng/mL

0 12 24 Time (hours)

IQ = LPV Ctrough = 5500 ng/mL

WT MEC for LPV = 1000 ng/mL= 5,5

However, the time required to exert the effect is not considered in the IQ equation

The slope of the curve (steepness) can be incorporated in the IQ equation as m :

Log (fa/fu) = m log(D/IC50)m1 m2 m3

Log (fa/fu) = m log(D/IC50)

Fraction of the viral population affected by the drug

Fraction of the viral population unaffected by the drug

Steepness of the curve

Drug concentration

Drug concentration inhibiting the 50% of viral growth

The effect of the virus is measured in a single-

round infectivity assay in vitro as infected cells (%) rather than as HIV-RNA fall per time unit (clinical

studies)

A new index is thus termed:

Instantaneous Inhibitory Potential (IIP)

IIPCmin = log (1/fuCmin)

= log [1+ (Cmin/IC50)m]

*

Using observed failure approach: RAL 92% and EFV 91%

83%

84%

0 4 8 16 24 32 40 48 60 72 84 96Week

0

20

40

60

80

100

Pa

tien

ts W

ith H

IV-1

RN

A

< 5

0 c

op

ies/

mL

(%

)

RAL 100 mg BID.RAL 200 mg BID.RAL 400 mg BID.RAL 600 mg BID.EFV 600 mg QD

But…….

These are the facts…….

EFV

RAL

Thus…..

• This is an in vitro assay……

• Data from phase I-II monotherapy trials in humans are available…..

• Clinically determined PK/PD findings generally show a reasonable degree of consistency across all drug development phases…..

• Humans remain the best model of human disease…..

CNS-Penetration Effectiveness (CPE) Ranks

Letendre S, et al. Arch Neurol 2008; 65: 65-70Varatharajan L, Thomas SA. Antivir Res 2009; 82: A99-A109

LOW INTERMEDIATE HIGH

Tenofovir Stavudine Zidovudine

Didianosine Lamivudine Abacavir

Zalcitabine Emtricitabine Delavirdine

Nelfinavir Efavirenz Nevirapine

Ritonavir Etravirine Lopinavir

Saquinavir Darunavir Amprenavir

Tipranavir Atazanavir Indinavir

Enfuvirtide Raltegravir Fosamprenavir

Maraviroc

0 0.5 1

Letendre, S. et al. Arch Neurol 2008;65:65-70.

Subjects who had lower central nervous system Penetration-Effectiveness (CPE) ranks were more likely to have detectable cerebrospinal fluid (CSF) viral load when CPE rank was analyzed

as a continuous variable (A) or as a categorical variable (B)

0% 100% 200% 300% 400% 500%

APV (20%)

NVP (80%)

APV (50%)

ABC (40%) ABC (150%) Female genital tract exposure

ZDV (200%)

IDV (200%)TDF (400%)

3TC (400%)

Nonnucleoside Reverse Transcriptase Inhibitors

Protease Inhibitors

Nucleoside Reverse Transcriptase Inhibitors

LPV (30%)

ATV (30%)

FTC (600%)EFV (0.6%)

LPV (5%)

EFV (3%)

IDV (100%)

NVP (70%)

TDF (500%)

3TC (600%)

ZDV (200%)

ABC (150%)

Male genital tract exposure

By courtesy of A. Kashuba

RAL (645%)

• Greater CYP450 enzyme inhibition specificity

• Less induction of drug metabolizing enzymes and transporters

Keys to Pharmacoenhancement

1 100

20

40

60

80

100

RTV

GS-9350

hPXR Activation

Concentration (µM)

Resp

onse

(%E m

ax)

Induction of Hepatocyte CYP3A4 mRNA

mean + SD, n=3

0

20

40

60

80

100

120

1 µM 3 µM 10 µM 30 µM Rifampicin

GS-9350

% M

axim

um

mean ± SD, n=3

CYP450 enzyme IC50

(µM)1A2 2B6 2C8 2C9 2C19 2D6 3A*

GS-9350 >25 2.8 30 >25 >25 9.2 0.2

RTV >25 2.9 5.5 4.4 >25 2.8 0.2

* midazolam 1’-hydroxylase (no preincubation)mean of 3 experiments conducted in duplicate

Acknowledgments

THE UNIVERSITY

of LIVERPOOL

TORINO:

Stefano Bonora

Antonio D’Avolio

Mauro Sciandra

Marco Siccardi

Daniel Gonzalez de Requena

Alessandro Sinicco

Sabrina Audagnotto

Cristina Tettoni

Laura Trentini

Andrea Calcagno

Anna Lucchini

Agostino Maiello

Ivan Dal Conte

LIVERPOOL:

David Back

Saye Khoo

Andy Owen

LONDON:

Marta Boffito

Anton Pozniak

ROMA:

Andrea Antinori

Emanuele Nicastri

Giuseppe Ippolito

Documents

Ospedale Amedeo di Savoia