Evaluation of Treatment with the Histone Deacetylase Inhibitor Vorinostat

(suberoylanilide hydroxamic acid; SAHA) in Antiretroviral Drug Treated, SIVmac239-Infected

Rhesus Macaques

J.D. Lifson AIDS and Cancer Virus Program, SAIC

Frederick, Inc. Frederick National Laboratory

“Towards an HIV Cure” Pre-Conference Symposium 20 & 21 July 2012

AIDS and Cancer

Virus Program

Frederick National Laboratory

Study Objectives

• Establish rigorous, useful model for cART suppression and evaluation of interventions targeting residual virus in cART suppressed SIV-infected Indian rhesus macaques

• Establish effective, sustainable cART regimen

• Establish virologic monitoring capability

• Establish assays for confirming pharmacodynamic activity of interventions

• Evaluate candidate interventions, starting with Vorinistat/SAHA

SIVmac239 cART SAHA

Evaluation of Vorinostat (SAHA) Treatment in cART Suppressed, SIVmac239 Infected Indian Rhesus Macaques:

Study Design

4 wks Necropsy

Bxs

SAHA treatment 2 cycles, 45 mg/kg, p.o., daily X 21 days, with off treatment interval; 2 cycles 57 mg/kg, p.o. daily X 21 days, with off treatment interval

(A*01, B*08, B*17 neg)

cART (started wk 4 p.i.) SubQ: PMPA (20 mg/kg/day) FTC (40 mg/kg/day) P.O.: L-812 (20 mg/kg, b.i.d./ L-564 (10 mg/kg, b.i.d.)/ DRV (600 mg, b.i.d.)/RTV (100 mg b.i.d.)

cART cART cART

cART cART cART

Effective Suppression of Plasma Viremia With Well Tolerated cART Regimen Pl

asm

a SI

V R

NA

(Cop

y Eq

/mL)

Weeks Post-Infection

0123456789

10

DC1G DCCP DCLJ DCEA DCEW DCT2

Neg Cont

Pos Cont

SAHA

Calc

ulat

ed F

requ

ency

of C

D4+ C

ells

W

ith In

duci

ble

SIV

RNA

(per

106 B

lood

CD4

+ Ce

lls)

1 - DMSO Control2 - 1uM SAHA3 - 5uM SAHA4 - PMA-Iono5 - Isotype

Ac-H4 Zen FITC-A

Co

un

t

-102 -101 102 103 1040

110

220

329

439

Ex Vivo SAHA Treatment Increases Histone Acetylation and Induces Expression of SIV RNA in CD4+T Cells from

ART-suppressed, SIV-infected Rhesus Macaques

0

50

100

150

200

250

300

350

400

450

500

Pre-

SAHA

1

SAHA

-1-1

SAHA

-1-2

SAHA

-1-3

pre-

SAHA

-2

SAHA

-2-1

SAHA

-2-2

SAHA

-2-3

pre-

SAHA

-3

SAHA

-3 +

4 h

r

SAHA

-3-1

SAHA

-3-2

SAHA

-3-3

pre-

SAHA

-4

SAHA

-4-1

SAHA

-4-2

Ac-H

4- M

FI

(% o

f Sam

e Cy

cle

pre-

SAH

A ba

selin

e) SAHA SAHA SAHA SAHA

In Vivo SAHA Treatment: Safety/Tolerance and Parmacodynamic Activity

• No clinically significant adverse events • Plasma levels variable (BLQ 2 uM, 4 hrs post-p.o. dose) • Variable treatment associated modification of histone acetylation in blood and LN CD4+ T cells

No Consistent Effect of In Vivo SAHA Treatment on Plasma Viremia in ART-suppressed, SIV-infected Rhesus Macaques

0

100

200

300

400

500

0.010

0.100

1.000

10.000

100.000W

k 29

; ART

, pre

-SAH

A-1

Wk

30; S

AHA-

1-1

Wk

31; S

AHA-

1-2

Wk

32; S

AHA-

1-3

Wk

33W

k 34

Wk

35; p

re-S

AHA-

2W

k 3

6; S

AHA-

2-1

Wk

37; S

AHA-

2-2

Wk

38; S

AHA-

2-3

Wk

39W

k 40

Wk

41W

k 42

Wk

43W

k 44

Wk

45; p

re-S

AHA-

3W

k 45

; SAH

A-3

+ 4

hrW

k 46

; SAH

A-3-

1W

k 47

; SAH

A-3-

2W

k 48

; SAH

A-3-

3W

k 49

Wk

50W

k 51

Wk

52W

k 53

; pre

-SAH

A-4

Wk

54; S

AHA-

4-1

Wk

55; S

AHA-

4-2

SIV

RNA:

SIV

DN

A

(Fol

d Ch

ange

from

sam

e cy

cle

bas

elin

e)

Variable Effects of SAHA Treatment on PBMC Cell Associated SIV RNA Levels in ART-suppressed, SIV-infected Rhesus Macaques

(Rh-DCCP) (RNA and DNA measurements as per Hansen et al, Nature, 2011)

Ac-

H4

(MFI

)

Preliminary Interpretation: Add’tl Analyses in Progress

• Low levels of cell associated SIV RNA in animals on cART; avg ~ 10 copy /106 PBMC • All 6 animals showed a > 3-fold increase in blood CD4+ cell SIV RNA:SIV DNA at least once during the four courses of treatment, consistent with induction of viral expression (4/4, 3/4, 3/4, 2/4, 2/4, 1/4)

• CAVL and Ac-H changes in relation to dosing not consistent within or between animals; background non-treatment related variation; PK/PD

• Ex vivo blood CD4 cell induction cultures at necropsy, 4 hrs after final (84th) SAHA dose - NO SIV RNA production in unstimulated control wells - SIV RNA readily inducible with additional SAHA treatment ex vivo

• Suggestion of activity, but treatment as given not optimal for maximal induction of viral RNA expression

Conclusions/Future Directions

• cART regimen(s) and suppression

• Frequency of CD4 cells with ex vivo inducible SIV RNA in cART-suppressed animals

• Safety/tolerance and in vivo PD activity of SAHA

• Induction of SIV RNA in vivo; relation to clinical data; kinetics/dynamics, sampling considerations

• Necropsy tissues and ex vivo RNA induction assays; correlate with IUPM

• Additional assay optimization

• Future combination studies, including immune modulators, therapeutic vaccination

Frederick National Laboratory

AIDS and Cancer

Virus Program

Contributors ACVP/SAIC-F G Del Prete D Schneider M Piatak K Oswald R Shoemaker Y Li R Fast M Trubey A Lara R Kiser V Coalter A Wiles R Wiles G Dasema J Estes B Keele

LASP/SAIC-F J Smedley R Macallister M Gathuka LMT/SAIC-F X Wu U Nebraska C Fletcher B Robbins

Merck D Hazuda C Tan J Wai R Sanchez Gilead R Geleziunas J Hesselgesser

Text

Funding: NCI/NIH Contract

HHSN261200800001E