1. Understanding the Spectrum of HIV Resistance The Very Rev. Drew Kovach, MD, MDiv Sharon Martens, MSL 20 June 2007 Honolulu Hawaii

2. DHHS Guidelines: Changing ARV Therapy in Highly Experienced Patients  Use treatment history and past and current resistance tests to identify ≥2 fully active ARVs* –Including an ARV with a new mechanism of action (e.g., fusion inhibitor, integrase inhibitor, CCR5 antagonist) to optimized background regimen may provide significant activity  Adding 1 active drug to a failing regimen is undesirable and leads to resistance –May be necessary in patients with advanced disease (e.g., CD4 <100) and high risk of clinical progression –In stable patients, waiting may be appropriate if drugs likely to be effective are to arrive soon *A fully active agent is one likely to demonstrate antiretroviral activity on the basis of both the treatment history and susceptibility on drug-resistance testing. Adapted from DHHS Guidelines. Available at: http://aidsinfo.nih.gov/Default.aspx. Revision October 10, 2006.

3. CD4 + Cell and HIV RNA Outcomes <50c/mL, blips and sustained LL viremia have similar CD4 count recoveries Transient viremia/blip Stable Low-level Viremia

4. What are the Options when Treatment Fails?  Continue current therapy  Interrupt treatment  Change the current regimen

5. Expectations May Differ According to Patient Dynamics Patient APatient B HIV RNAIncreasingStable, low CD4 CountLowHigh Prior Rx OptionsFewMany Missed DosesFrequentRarely Prior Experience ENF, NNRTI- Other Factors Child-Pugh B ABC HS - ART GOALHIV RNA < 50

6. Continuation of Current Therapy

7. Viremia Leads to Resistance and Loss of Active Drugs  SCOPE cohort: Treatment- experienced patients (n = 106) –Stable ART for ≥ 120 days –HIV RNA > 1000 copies/mL –≥ 1 resistance mutation –Resistance testing every 4 months until ART modification  New mutations at 1 year –Any: 44% (95% CI 33–56) –NAM: 23% (95% CI 15–34) –PI: 18% (95% CI 9–34) Number of available ARVs from the following: ZDV, 3TC, ddI, ABC, TDF, EFV, IDV, NFV, SQV, RTV, APV, LPV 0 0.25 0.50 0.75 1.00 04812162024 Time (months) Without loss of 1 drug equivalent 1 new major PI mutation * 1 new NRTI mutation Any new mutation * Data are for PI-treated subjects (n = 71) 048121620 24 Time (months) Without new mutation 0 0.25 0.50 0.75 1.00 Hatano H, et al. 13th CROI (2006). Abst. 615

8. Interruption of Treatment

9. Partial Treatment Interruptions Interruption of Enfuvirtide in HIV-1 Infected Adults with Incomplete Viral Suppression on an Enfuvirtide-based Regimen Deeks et al JID in press

10. Change in Treatment Regimen

11. Recent and Anticipated Agents  NNRTIetravirine (TMC125)  PI/rdarunavir/r tipranavir/r  Fusion Inhibitor enfuvirtide  Tropism Antagonist maraviroc vicriviroc  Integrase Inhibitorraltegravir (MK0518) elvitegravir (GS9137) The underlined agents are currently available through expanded access programs and/or clinical trials

12. Resistance Testing will be Critical to Optimal use of New Agents

13. Resistance Testing  Genotyping: Geneseq  Phenotyping: PhenoSense  Combination phenotype + genotype: PhenoSense GT  Other Clinically Relevant Tests –Tropism Profiling: Trofile –Integrase Resistance Testing: In development –Enfuvirtide Phenotyping: PhenoSense Entry –Replication Capacity

14. Resistance Testing  Genotyping  Simple rules based interpretation (RBI)  More advanced RBI  Virco Type, Stanford HIV database, geno2pheno  Phenotyping  PhenoSense, Antivirogram, PhenoScript  Combination genotype/phenotype  PhenoSenseGT

15. Genotypic Report  Genotypic data provide an assessment of resistance as either sensitive or resistant

16. Genotypic Report Genotypic mutations-by drug HIV Clade Genotypic resistance is identified using the largest phenotypic-genotypic database

17. Genotypic Testing Advantages:  Useful for simple resistance profiles, e.g., K103N  May have a shorter Turn-Around-Time  Lower cost  Can provide information about mixtures Limitations:  Resistance is inferred not actually measured  Results only in a Yes/No format  Less useful when genotypes are very complex  Often not optimized for ‘new’ drugs

18. PhenoSense HIV

19. TransfectionInfection PR Inhibition Resistance Test Vector DNA RT Inhibition A-MLV env DNA + +

20. Patient’s virus is sensitive to the drug Nelfinavir % Inhibition IC 50 (patient) IC 50 (control) Fold Change = FC=1 Phenotypic Inhibition Curves Patient: Control:

21. Phenotypic Inhibition Curves Patient: Control: Nelfinavir % Inhibition FC=8

22. PhenoSense HIV Test Report

23. PhenoSense Summary Page

24. Replication Capacity RC value indicates the ability of the patient’s virus to replicate relative to the median of wild-type population of viruses Median RC value of a wild-type population of viruses defined as 100%

25. Phenotypic Testing Advantages:  Actual measure of drug susceptibility  Allows for graduation of resistance  Can be used with new drugs  Avoids the need to interpret complex genotypic patterns Limitations:  Can be less sensitive to mixtures  More expensive than genotyping

26. Combination Phenotype and Genotype

27. PhenoSense GT Report

29. Recent Clinical Trials utilizing PhenoSense or PhenoSense GT to Optimize Background Therapy NameAgent BENCHMARK 1 & 2Raltegravir MOTIVATE 1 & 2Maraviroc TORO 1 & 2Enfuvirtide ACTG 5211Vicriviroc 1026 & 1029Maraviroc GS9137Elvitegravir

30. Defining Sensitive and Resistant

31. Genotype Calls Probability of response Fold Change Fully Sensitive = Complete Response Resistant means ?

32. Probability of response Fold Change Lower clinical cutoff: The fold change at which the HIV RNA response first begins to decline Upper clinical cutoff: The fold change above which a clinically meaningful HIV RNA response (>0.3 log 10 ) is unlikely Zone of Intermediate Response Definitions

33. Week 4 HIV RNA Change for all Isolates within Power 1, 2 and 3 Week 4 HIV RNA (log 10 ) Change Baseline DRV fold change (log 10 ) ENF recipients excluded from this analysis N=173

34. Mean HIV RNA Outcome by DRV FC Groups (All Data) Comparisons of mean HIV RNA changes for susceptible and intermediate groups p <.0001. *p=.049, **p=.07, ^p=.02, ^^p=.2, ^^^p=.03

35. Darunavir Clinical Cutoff  The maximal DRV activity is observed over an extended FC range to approximately 10, the lower clinical cutoff  DRV activity reduces in a graduated fashion from 10 fold change to 90 the upper clinical cutoff

36. Unusual Resistance Patterns

37. PhenoSense GT Report

38. Enhancing EFV Susceptibility by NRTI Resistance K65R+M184V K65R L74I/V M184V C Chappey et al, Abstract 95, XIV International HIV Drug Resistance Workshop:. June 7-11, 2005. Québec City, Québec, Canada TAMS + 74I/V

39. PhenoSense GT Report

40. ZDV Resistance and Resensitization 100I 65R 74V/I 100I 181C 184I/V 41L, 210W, 215Y 67N, 70R, 215F, 219Q TFV

41. PhenoSense GT Report

42. Putting It All Together

43. How Might We Combine These Newer Agents? A NRTI NNRTI PI B DRV/r ETV D Raltegravir Maraviroc C ENF Resistance Test Resistance Test Tropism Test

44. Define Optimized Background for this Patient Current Regimen 3TC, ABC, ATV/r

45. 30% 60% <400 c/ml W24 Patients (%) TORO 1, 2 LPV/r LPV/r + ENF 46% 64% <50 c/ml W24 POWER 1, 2 DRV/r DRV/r + ENF 30% 54% RESIST 1, 2 TPV/r TPV/r + ENF <400 c/ml W24 Haubrich R, et al. 43rd IDSA (2005). Abst. 785; Lazzarin A, et al. N Engl J Med 2003;348:2186-95; Moyle GM, et al. 12th BHIVA (2006). Abst. P1. Adding a New Class: Enfuvirtide

46. New Class (ENF) + Improving OB 18% 35% 53% 52% 0% 13% 21% 38% 0 10 20 30 40 50 60 70 80 90 100 0123 % of Patients <50c/mL Wk 24 ENF + OB OB Number of Fully active ARVs in OB (Phenotypic Susceptibility) 1911621339799688050 N=

47. New Class (RGV) + Improving OB ENF and DRV use in naïve patients were each counted as +1 active agent and added to PSS. Cooper D and Steigbigel R, et al. 14th CROI (2007). Absts. 105aLB and 105bLB. 0 1 ≥2 Patients <400 c/mL at Week 16* (%) Patient Number 62 222110 14168 44 61% 5% 79% 41% 87% 57% 0 10 20 30 40 50 60 70 80 90 100 Raltegravir Placebo BENCHMRK 1 & 2 Number of Fully active ARVs in OB (Phenotypic Susceptibility)

48. *Based on overall susceptibility score (LOCF) Nelson M and Lalezari J, et al. 14th CROI (2007). Absts. 104aLB and 104bLB. Patients <50 c/mL at Week 24 (%) Patient Number 35 5988130134 56 4451 104 13264121 0 1 2 ≥3 MOTIVATE 1 & 2 Placebo Maraviroc BID 55% 19% 9% 3% 58% 53% 43% 29% 0 10 20 30 40 50 60 70 New Class (MVC-R5) + Better OB Number of Fully active ARVs in OB (Phenotypic Susceptibility)

49. *Data from EVG (125 mg) patients after addition of a PI were excluded Change in HIV RNA with Elvitegravir Influence of activity of OB EVG (125 mg) with no active drugs in OBT (n=26) EVG (125 mg) with >1 active NRTI or first use of ENF (n=47) 04812162024 -2 0 -2.1 -0.7 p<0.001 Week Mean change from BL in HIV RNA (log 10 c/mL) Zolopa A, et al. 14 th CROI, Los Angeles 2007, #143LB

50. The ARV pipeline: 2007-2010 Protease Inhibitors NNRTIs NRTIs Maturation inhibitor Integrase inhibitorsEntry inhibitors 2010200920082007 PA 457 Panacos Maraviroc* Pfizer PRO 140 Progenics BILR 355 BI Etravirine* Tibotec GS9137 Gilead MK0518* Merck SPD 754 Avexa MAb004 HGS TNX355T anox Vicriviroc Schering Elvucitabine Achillion Racivir Pharmasset GS9148 Gilead DOT Emory TMC278 Tibotec Note: Estimated earliest US launch dates All dates are subject to adjustment *EAP Available

51. Conclusions  These studies remind us that we should avoid using new agents as ‘functional monotherapy’  ‘Adding one active drug to a failing regimen is undesirable and leads to resistance’  The regimen goal should be to: ‘Identify ≥2 fully active ARVs by treatment history and past and current resistance testing data’  Appropriately utilized Resistance Testing will be a cornerstone of new regimen construction *A fully active agent is one likely to demonstrate antiretroviral activity on the basis of both the treatment history and susceptibility on drug-resistance testing. Adapted from DHHS Guidelines. Available at: http://aidsinfo.nih.gov/Default.aspx. Revision October 10, 2006.

52. Patient JD  58 year old gay white male  Infected since 1990  Never undetectable  Heavily drug experienced  Abacavir hypersensitivity reaction  Declined enfuvirtide

53. Regimen as of 1/2004  Stavudine  Lamivudine  Tenofovir  Efavirenz  Labs: VL 59,900 CD4 = 112(4%)

54. PhenoSense GT  February 2, 2004

57. Regimen as of 4/2004  Lamivudine  Tenofovir  Lopinavir/r  Labs: VL 15,100 CD4 = 99(4%)  Saquinavir added  Labs 2 months later: VL 1200 CD4 = 134(6%)

58. Regimen as of 12/2005  Lamivudine  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 78,400 CD4 = 88(4%)

59. PhenoSense GT  December 27, 2005

62. Regimen as of 1/2006  Lamivudine  Tenofovir  Lopinavir/r  Saquinavir  Patient elected to make no changes since very low RC

63. Regimen as of 3/2007  Lamivudine  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 9294 CD4 = 56(2%)

64. PhenoSense GT  March 9, 2007

68. Regimen as of 4/2007  Tenofovir/Emtricitabine  Tipranavir/r  Raltegravir  Current labs: VL<75 CD4 = 66(3%)

69. Patient DB  58 year old gay white male  Infected 1985  Never undetectable  Heavily drug experienced  Sulfa allergic  Hepatitis C failed therapy  4+ cirrhosis/ 4+ inflammation

70. Regimen as of 1/2004  Tenofovir  Lamivudine  Atazanavir/r  Enfuvirtide  Labs: VL 16,900 CD4 = 136(10%)

71. PhenoSense GT  February 24, 2004

74. Regimen as of 4/2004  Lamivudine  Abacavir  Tenofovir  Lopinavir/r  Saquinavir  Enfuvirtide stopped at patient request  Labs: VL 2,230 CD4 = 97(9%)

75. Regimen as of 1/2007  Lamivudine  Abacavir  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 58,793 CD4 = 36(4%)

76. PhenoSense GT  February 5, 2007

80. Regimen as of 4/2007  Tenofovir/Emtricitabine  Efavirenz  Darunavir/r  Current labs: VL<75 CD4 = 87(6%)

81. Patient WW  57 year old gay white male  Infected since 1988  Never undetectable  Heavily drug experienced  Extremely sulfa allergic  Abacavir hypersensitivity reaction  Declined enfuvirtide

82. Regimen as of 6/2005  Zidovudine/Lamivudine  Atazanavir/r  Labs: VL >100,000 CD4 = 75(3%)

83. PhenoSense GT  July 6, 2005

86. Regimen as of 9/2005  Stavudine  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 55,000 CD4 = 87(4%)

87. PhenoSense GT  March 21, 2006

90. Regimen as of 4/2006  Lamivudine  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 76,500 CD4 = 78(4%)

91. Regimen as of 3/2007  Lamivudine  Tenofovir  Lopinavir/r  Saquinavir  Labs: VL 74,167 CD4 = 66(3%)

92. Regimen as of 4/2007  Tenofovir/Emtricitabine  Darunavir/r  Etravirine  Current Labs: VL<75 CD4 = 54(3%)