0. CCR5 Antagonists and Tropism Testing in Clinical Practice
The Body PRO Presents:
CCR5 Antagonists and Tropism Testing in Clinical Practice
Faculty: W. David Hardy, M.D. Director, Division of Infectious Diseases Cedars-Sinai Medical Center; Los Angeles, California
W. David Hardy, M.D.
This activity is supported by educational grants from
This activity is jointly sponsored by Postgraduate Institute for Medicine and The Body PRO.
Copyright © 2008 Body Health Resources Corporation. All rights reserved.

1. Faculty for This Activity
W. David Hardy, M.D. W. David Hardy, M.D., is an associate professor of medicine-in-residence at the David Geffen School of Medicine, University of California, Los Angeles (UCLA). He gained his medical degree from the Baylor College of Medicine in Houston, Texas, in 1981, completed a residency in internal medicine at Harbor-UCLA Medical Center in Torrance, California in 1984 and a clinical fellowship in infectious diseases and immunology in 1986 at UCLA School of Medicine. Later in his career he also completed a postdoctoral fellowship in basic retrovirology in 2002, also at the UCLA School of Medicine. Dr. Hardy has conducted clinical trials with several antiretroviral agents beginning in He is a member of numerous professional societies including the American Academy of HIV Medicine, for whom he serves as a member of the National Board of Directors and Chairman of the California/Hawaii Chapter. Disclosures
Dr. Hardy has received grants or research support from Boehringer Ingelheim, Gilead Sciences, GlaxoSmithKline, Pfizer and Tibotec. He has served as a consultant for Boehringer Ingelheim, Bristol-Myers Squibb, GlaxoSmithKline, Merck, Monogram, Pfizer and Tibotec. He has received fees for non-CME services from Gilead Sciences, Pfizer and Tibotec. He owns stock in Merck.

2. Coreceptor, CD4 Binding Inhibitors Reverse Transcriptase Inhibitors
Retrovirus Life Cycle
Coreceptor, CD4 Binding Inhibitors
maraviroc
vicriviroc
TNX 355
Maturation Inhibitor
bevirimat
Fusion Inhibitors
enfuvirtide
Protease Inhibitors
saquinavir
indinavir
ritonavir
nelfinavir
fosamprenavir
lopinavir
atazanavir
tipranavir
darunavir
Reverse Transcriptase Inhibitors
zidovudine
nevirapine
didanosine
delavirdine
zalcitabine
efavirenz
stavudine
lamivudine
emtricitabine
abacavir
tenofovir
etravirine
rilpivirine
Integrase Inhibitors
raltegravir
elvitegravir

3. Adapted from Moore JP, PNAS 2003;100:10598-10602.
HIV Entry Inhibitors
Adapted from Moore JP, PNAS 2003;100:

4. Targets Involved in HIV Entry
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

5. Structure of the HIV-1 Envelope Glycoprotein
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

6. Binding of the gp120 Subunit to CD4
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

7. Conformational Change
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

8. gp120 Binds to the Coreceptor, CCR5
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

9. Conformational Changes in the gp41 Subunit
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

10. Fusion of the Viral and Cell Membranes
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

11. HIV Natural History and Tropism Expression

12. CCR5 Function and Genetics
CCR5 is a receptor for C-C chemokines (chemo-attractive cytokines)
Expressed on immune effector cells and antigen presenting cells
Molecules that bind to CCR5 include MIP-1, MIP-1, and RANTES
Activation of CCR5 on T cells by chemokines leads to:
T-cell migration to the site of inflammation
Immune response to various antigens
CCR5, together with CD4, are the primary receptors utilized by HIV for viral entry
Galvani AP et al. Proc Natl Acad Sci U S A. 2003;100: McNicholl JM et al. Emerg Infect Dis. 1997;3:
Stephens JC et al. Am J Hum Genet. 1998;62:

13. Mixed or Dual-Tropic Viruses Use CCR5 and/or CXCR4 (in vitro)
Graeme Moyle et al. ICAAC 2006; abstract H Reprinted with permission.

14. Coreceptor Usage of HIV-1 VariantsX4 R5
CXCR4
CCR5
CD4
T-cell lines
Primary lymphocytes
Monocyte/macrophages
CD4 Naive CD4 memory
Copyright © Pfizer Inc. All rights reserved.

15. Global Prevalence of CCR5 D32 Allele
~14%
~6%
Rare
10%-15%
~10%
5%-14% of Caucasians of European descent carry CCR5 32 (1% are CCR5 32 homozygous)
The origin of the CCR5 D32 allele has been traced to European geography ~1,000 years ago
Possible selection by pandemic pathogen, likely smallpox or bubonic plague
Galvani AP et al. PNAS. 2003;100: McNicholl JM et al. Emerg Infect Dis. 1997;3:
Stephens JC et al. Am J Hum Genet. 1998;62:

16. CCR5 Wild Type and CCR5 32 Normal Heterozygotes Homozygotes
wt/wt
wt/32
32/32
Normal CCR5 exp
Progression of HIV
Normal immune fx*
Decreased CCR5 exp
Delayed prog. to AIDS/death
Normal immune fx*
No CCR5 exp
Rare infection with X4
Normal immune fx*
*fx = function
Click on slide for animation. Liu R et al. Cell. 1996;86: Huang Y et al. Nat Med. 1996;2: Samson M et al. Nature. 1996;382: Michael NL et al. Nat Med. 1997;3: Dean M et al. Science. 1996;273: Eugen-Olsen J et al. AIDS. 1997;11:

17. Patients Heterozygous for CCR5 32 Have Slower Progression to AIDS and Death
Adapted from de Roda Husman A-M, et al. Ann Intern Med. 1997;127:

18. The Tropism Assay

19. Why is a Tropism Test Required?
CCR5 antagonists block entry of HIV that uses CCR5 only, no effect on HIV that uses CXCR4
Presence of X4 HIV has been associated with more rapid CD4 decline and disease progression
The effect a CCR5 antagonist will have in patients with R5/X4 HIV is unknown
Regulatory agencies likely to require tropism assay prior to use of a CCR5 antagonist
Copyright © Pfizer Inc. All rights reserved. Reprinted with permission.

20. The Monogram Tropism Assay
HIV-1 Expression Vector (pHIVlucU3)
Envelope Expression Vector (pHIVenv) P A+
HIV envelope
a/b
c/d
Indicator Gene U5
gag
pol
Luciferase R
 env
gp gp41
Copyright © Monogram Biosciences. Reprinted with permission.

21. HIV Entry Cell Assay
Adapted from Petropoulos CJ et al. Antimicrob Agents Chemother. 2000;44:

22. HIV Entry Cell Assay: R5 HIV Only
Adapted from Petropoulos CJ et al. Antimicrob Agents Chemother. 2000;44:

23. HIV Entry Cell Assay: X4 HIV Only
Adapted from Petropoulos CJ et al. Antimicrob Agents Chemother. 2000;44:

24. HIV Entry Cell Assay: R5/X4 Tropic HIV
Adapted from Petropoulos CJ et al. Antimicrob Agents Chemother. 2000;44:

25. Demonstration of R5 Virus
Light Generated CCR5 Use
R5 Virus
Virus
No Light Generated No CXCR4 Use
Not an X4 Virus
Virus
Virus
CCR5
CXCR4
Click on slide for animation. Copyright © Monogram Biosciences. Reprinted with permission.

26. Demonstration of Dual Virus
Light is generated on both CCR5 and CXCR4 cell lines.
This is a DUAL virus.
Virus
Virus
Virus
Virus
CCR5
CXCR4
Click on slide for animation. Copyright © Monogram Biosciences. Reprinted with permission.

27. Demonstration of Mixed Virus Population
This population shows CCR5 AND CXCR4 co-receptor use.
This is a mixed population.
CCR5
CXCR4
Click on slide for animation. Copyright © Monogram Biosciences. Reprinted with permission.

28. What Is This Population?
Most of these viruses are R5:
Strong luciferase activity
Some are X4: Lower level luciferase activity
CCR5
CXCR4
Click on slide for animation. Copyright © Monogram Biosciences. Reprinted with permission.

29. Comparison of Original Tropism to Enhanced Sensitivity Tropism Test
Standard Tropism Assay (August 2007 – June 2008)
Enhanced Tropism Assay (June 2008 – Present)
Sensitivity
100% if X4-using HIV > 10% of viral population
83% if X4-using HIV > 5% of viral population
100% if X4-using HIV > 0.3% of viral population
Plasma Volume Required
3 mL
Shipping Requirement
Dry ice
Viral Load Requirement
> 1,000 copies/mL
Turnaround Time
~ 2 weeks
Copyright © Monogram Biosciences. Reprinted with permission.

30. Coreceptor Tropism: Epidemiological Data

31. Percentage of HIV Coreceptor Usage
Study/Source
Population N R5 X4
R5/X4
Homer cohort1
Naive
979
82%
< 1%
18%
C & W cohort2
402
81%
19%
Demarest3
299
88% 0%
12%
Study 10264
Naïve
1428
85%
15%
TORO 1/26
Experienced
612
62% 4%
34%
ViroLogic5
> 2000
48% 2%
50%
ACTG 52117
391
49%
47%
MOTIVATE 1/28
2560
56% 3%
41%
This table may not include all available reported data; majority of data are generated in the developed world (subtype B)
1Brumme ZL et al. J Infect Dis. 2005;192: Moyle GJ et al. J Infect Dis. 2005;191: Demarest J et al. ICAAC 2004; abstract H Waters L et al. ICAAC 2006; abstract H Whitcomb JM et al. CROI 2003; abstract Paxinos EE et al. ICAAC 2002; abstract 2040.
7Wilkin T et al. CROI 2006; abstract Coakley E et al. International Workshop on Targeting HIV Entry 2006; abstract 8.

32. Prevalence of X4 Phenotype by Baseline CD4+ Count
100
92.8
Coreceptor use was determined in 1191 patients starting HAART
Patients with D/M virus had a poorer clinical profile than patients with R5 virus
Median CD4+ T-cell count of 110 versus 290 cells/mm3 (P<.0001)
HIV RNA of 175,000 versus 120,000 copies/mL (P=.0006)
The following were associated with the prevalence of D/M-tropic virus:
Low baseline CD4+ T-cell count
High baseline HIV RNA
CCR5-Δ32 deletion heterozygous patients
Basic mutations at gp120-V3 codons 11 or 25 80
54.4 60 R5
Percentage of Patients
D/M 40
45.6 20
7.2
< 25
25-49
50-99
≥ 500
Baseline CD4
Adapted from Brumme ZL et al. J Infect Dis. 2005:192;466-74

33. Tropism in Naive Patients: Impact on CD4+ Decline and Response to Treatment
402 treatment-naive subjects had tropism tested
326 R5
73 D/M
3 X4
340 started HAART by August 2006
229 R5
60 D/M
51 excluded from analysis
Graeme Moyle et al. ICAAC 2006; abstract H Reprinted with permission.

34. CD4+ Decline Before HAART
DAVG analysis (time weighted differences in average. Censored at HAART; Error bars are 95% CI
Graeme Moyle et al. ICAAC 2006; abstract H Reprinted with permission.

35. Time to Viral Suppression
Survival analysis; Cox’s proportional hazards regression to adjust for baseline HIV RNA and HAART
Graeme Moyle et al. ICAAC 2006; abstract H Reprinted with permission.

36. Tropism Does Not Affect Response to HAART
R5 Tropic
R5/X4 Tropic
P Value
CD4+ T-Cell Count Rise at 12 Months, Cells/mm3 (95% CI)
185 ( )
182 ( )
.812
CD4+ T-Cell Count Rise at 24 Months, Cells/mm3 (95% CI)
247 ( )
292 ( )
.482
Patients With VL < 50 Copies/mL at 12 Months, n (%)
168 (73.4)
47 (78.3)
.509
Patients With VL < 50 Copies/mL at 24 Months, n (%)
166 (72.4)
41 (68.3)
.67
CI = confidence interval
Graeme Moyle et al. ICAAC 2006; abstract H Reprinted with permission.

37. Clinical Trials

38. MOTIVATE 1&2: Trial Design
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

39. MOTIVATE 1&2: Demographics and Baseline Characteristics
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

40. MOTIVATE 1&2: Mean Change in HIV-1 RNA* From Baseline to Week 48
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

41. MOTIVATE 1&2: Percentage of Patients With Undetectable HIV-1 RNA
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

42. MOTIVATE 1&2: Mean Change in CD4+ Cell Count From Baseline to Week 48
CD4+ cell count increases up to 48 weeks were more favorable in both the maraviroc groups than the placebo group
The mean change from baseline in CD4+ cell count* was:
+61 cells/mm3 in the placebo + OBT
+116 cells/mm3 in maraviroc QD + OBT
+124 cells/mm3 in the maraviroc BID + OBT group
* Last observation carried forward approach used to impute missing values
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

43. David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.
MOTIVATE 1&2: Patients With HIV-1 RNA < 50 Copies/mL by Screening Viral Loads and Baseline CD4+ Cell Count (Week 48)
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

44. MOTIVATE 1&2: Safety Analyses Unadjusted For Duration of Exposure
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

45. David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.
MOTIVATE 1&2: Maximum Liver Function Test Values Over 48 Weeks Without Regard To Baseline
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

46. David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.
MOTIVATE 1&2: Percentage of Adverse Events Occurring in ≥ 5% of Patients in Any Group, Unadjusted for Treatment Exposure
David Hardy et al. CROI 2008; abstract 792. Reprinted with permission.

47. VICTOR-E1: Phase IIb Trial of Vicriviroc in Treatment-Experienced Patients
Barry Zingman et al. CROI 2008; abstract 39LB. Reprinted with permission.

48. VICTOR-E1: Virologic Efficacy of Vicriviroc vs. Placebo at Week 48
VCV 30 mg n = 39
VCV 20 mg n = 40
Placebo n = 35
100
Patients With HIV-RNA-1 < 50 copies/mL (%)
Mean Change in HIV-1 RNA From BL (log10 copies/mL) 90
-0.2 80
-0.4 70
-0.6 56 60 53
-0.8
-0.79 50
-1.0 40
-1.2 30
-1.4 20 14
-1.6 10
-1.8
-1.77
-1.75
Difference: P = .0028
-2.0
Difference: P = .0017
VCV 30 mg n = 22
VCV 20 mg n = 21
Placebo n = 5
No clinically significant differences in adverse events between VCV arms and placebo
Barry Zingman et al. CROI 2008; abstract 39LB. Reprinted with permission.

49. MERIT: Maraviroc vs. Efavirenz in Treatment-Naive Patients
Stratified by HIV-1 RNA < or  100,000 copies/mL and by Northern or Southern Hemisphere
Week 48 primary endpoint
Week 96
MVC 300 mg twice daily + ZDV/3TC
(n = 360)
Antiretroviral-naive patients infected with CCR5-tropic HIV-1 and HIV-1 RNA  2000 copies/mL
(N = 740)
EFV 600 mg once daily + ZDV/3TC
(n = 361)
MVC 300-mg once-daily arm discontinued early due to failure to demonstrate noninferiority to efavirenz at end of phase IIB (Week 16)
Stringent noninferiority margin: -10% for lower bound of 1-sided 97.5% CI
Michael Saag et al. IAS 2007; abstract WESS104. Reprinted with permission.

50. MERIT: Patients With Viral Load < 400 and < 50 Copies/mL by Week 48 (ITT)
EFV (n = 361)
MVC (n = 360)
100
VL < 400 copies/mL
100
VL < 50 copies/mL
73.1% 80 80
69.3% 60
70.6% 60
65.3%
Patients, %
Patients, % 40 40 20 20 2 4 8 16 24 32 40 48 2 4 8 16 24 32 40 48
Time (weeks)
Time (weeks)
MVC was noninferior to EFV only for < 400 copies/mL endpoint (70.6% vs 73.1%)
CD4+ cell count increases were higher in patients receiving MVC vs EFV (+170 vs +144 cells/mm3)
Michael Saag et al. IAS 2007; abstract WESS104. Reprinted with permission.

51. MERIT: Patients With Viral Load < 50 Copies/mL by Baseline Viral Load
EFV patients more likely to discontinue due to AE
Overall : 25.2%
AE: 13.6%
Efficacy: 4.2%
MVC patients more likely to discontinue due to lack of efficacy
Overall: 26.9%
AE: 4.2%
Efficacy: 11.9%
EFV
MVC
100 90 80
71.6
69.6 70
66.6
59.6 60
Patients, % 50 40 30 20 10
n =
211
204
150
156
BL VL < 100,000 Copies/mL
BL VL ≥ 100,000 Copies/mL
Michael Saag et al. IAS 2007; abstract WESS104. Reprinted with permission.

52. MERIT: Week 48 Safety Analyses
All Causalities and Severities
EFV + CBV N=361
MVC + CBV N=360
Patients With Adverse Events
340 (94.2)
331 (91.9)
Patients With Grade 3 AEs, n (%)
66 (18.3)
51 (14.2)
Patients With Grade 4 AEs, n (%)
24 (6.6)
22 (6.1)
Patients With SAEs, n (%)†
46 (12.7)
41 (11.3)
Patients With Category C events, n (%)
12 (3.3)
6 (1.7)
Malignancies
16 (4.4)
10 (2.8)
Deaths†*, n (%) 1
AEs = adverse events; SAEs = serious adverse events †Based on all data through 21 June 2007 *Deaths reported up to 28 days after stopping study drug; one additional death on EFV within 28 days, date of death not captured in database
Michael Saag et al. IAS 2007; abstract WESS104. Reprinted with permission.

53. MERIT: Viral Suppression at Week 48 by Baseline Tropism20 30 70 10 40 50 60 80 90
100
69.3
54.6
7.1
n = 11 14
68.0
339
331
Patients With VL < 50 c/mL at Week 48 (%)
EFV
MVC
65.3
Tropism at Screening (Overall)
361
360
Tropism at Baseline (R5)
Tropism at Baseline (D/M)
• Change in detected HIV-1 tropism from R5 at screening to D/M at BL and potentially adherence may explain some treatment failures on MVC
3.5% of patients experienced change in detected tropism between screening and BL
50.0% of patients with R5 virus at BL and without confirmed X4 at failure had plasma MVC concentrations below limit of detection
• Tropism changes more common in patients with lower mean CD4+ cell count at screening as well as with clade B or other/undetermined HIV-1 subtype vs clade C
Jayvany Heera et al. CROI 2008; abstract 40LB. Reprinted with permission.

54. MERIT: Fewer Lipid Effects With Maraviroc vs. Efavirenz at Week 48
Edwin DeJesus et al. CROI 2008; abstract 929. Reprinted with permission.

55. Questions

56. Main Discussion Questions
Does the use of CCR5 antagonists prevent the immune system from mounting an effective defense against West Nile virus infection and its complications?
Is the new enhanced tropism test sensitive enough to more accurately identify patients who may have some X4-tropic virus?
Is there going to be a second clinical trial of maraviroc in treatment-naive patients that uses the more sensitive assay?
Who is the best patient to use a CCR5 antagonist?