1. A Multicenter, Randomized, Double-Blind, Comparative Trial of a Novel CCR5 Antagonist, Maraviroc Versus Efavirenz, both in Combination with Combivir (Zidovudine/Lamivudine), for the Treatment of Antiretroviral-Naive Subjects Infected with R5 HIV 1: Week 48 Results of the MERIT Study Abstract Number WESS104 4th IAS, Sydney, July 2007 Michael Saag 1, Prudence Ive 2, Jayvant Heera 3, Margaret Tawadrous 3, Edwin DeJesus 4, Nathan Clumeck 5, David Cooper 6, Andrzej Horban 7, Lerato Mohapi 8, Horacio Mingrone 9, Gustavo Reyes-Teran 10, Sharon Walmsley 11, Frances Hackman 12, Elna van der Ryst 12, Howard Mayer 3 1 University of Alabama at Birmingham, Birmingham, USA 2 University of the Witwatersrand, Clinical HIV Research Unit, Johannesburg, South Africa 3 Pfizer Global Research and Development, New London, USA 4 Orlando Immunology Center, Orlando, USA 5 Saint-Pierre University Hospital, Infectious Diseases, Brussels, Belgium 6 University of New South Wales, National Centre in HIV Epidemiology and Clinical Research, Sydney, Australia 7 Hospital of Infectious Diseases, Warsaw, Poland 8 University of the Witwatersrand, Perinatal HIV Research Unit, Johannesburg, South Africa 9 HIV Outpatient Care Unit, Muñiz Hospital, Buenos Aires City, Argentina 10 Instituto Nacional de Enfermedades Respiratorias, Center for Research in Infectious Diseases, Tlalpan, Mexico 11 University of Toronto, Toronto, Canada 12 Pfizer Global Research and Development, Sandwich, UK

2. 2 Randomization 1:1 MERIT Study: Phase 3 Trial Design Maraviroc (MVC 300 mg BID) + Combivir (ZDV+3TC)* Efavirenz (EFV 600 mg QD) + Combivir (ZDV+3TC)* Primary analysis 0 48 wk 96 wk Screening (6 weeks) Patients stratified by: HIV-1 RNA < and ≥100,000 copies/mL at screening Geographic location: Northern Hemisphere and Southern Hemisphere Patient eligibility criteria: ≥16 years of age Treatment naive R5 HIV-1 infection First patient visit Nov 2004 HIV-1 RNA ≥2,000 copies/mL No evidence of resistance to EFV, ZDV, or 3TC *Patients experiencing toxicity to ZDV or 3TC were permitted to substitute an alternative NRTI MVC QD arm discontinued at end of Phase 2b (week 16) for failure to meet protocol-defined criteria to continue (205 pts completed 16 weeks)

3. 3 Demographics and Baseline Characteristics Randomized: N=740 Treated: N=721 EFV + CBV N=361 MVC + CBV N=360 Mean age, yrs (range) 37.4 (18–77)36.7 (20–69) Male, n (%) 259 (71.7)256 (71.1) Race, n (%) White Black Asian Other 198 (54.8) 133 (36.8) 5 (1.4) 25 (6.9) 204 (56.7) 123 (34.2) 6 (1.7) 27 (7.5) Median CD4+ count, cells/mm 3 (range)254 (8–1,053) 241 (5–1,422) Mean HIV-1 RNA, log 10 copies/mL (SD)4.88 (0.699) 4.86 (0.640) MERIT Study 48 weeks

4. 4 Summary of Discontinuations Through 48 Weeks Reason for discontinuation EFV + CBV N=361 MVC + CBV N=360 All, n (%) 91 (25.2)97 (26.9) Adverse event, n (%) 49 (13.6)15 (4.2) Lack of efficacy, n (%) 15 (4.2)43 (11.9) Other reason, n (%) 9 (2.5)14 (3.9) Withdrew consent or lost to follow-up, n (%)18 (5.0)25 (6.9) Includes all patients who received at least one dose of study medication MERIT Study 48 weeks

5. 5 Percentage of Patients with Undetectable HIV-1 RNA by Visit Includes all patients who received at least one dose of study medication MERIT Study 48 weeks Missing values classified as failures/non-responders <400 copies/mL<50 copies/mL EFV + CBV (N=361) MVC + CBV (N=360) Patients (%) Time (weeks) 0 10 20 30 40 50 60 70 80 90 100 2 4 8 16 243240 48 2 4 8 16 24 32 4048 70.0% 72.6% 69.0% 64.4% 0 10 20 30 40 50 60 70 80 90 100

6. 6 Percentage of Patients with Undetectable HIV-1 RNA at Week 48 (Primary Endpoint) 0 10 20 30 40 50 60 70 80 90 100 361 360361 360 73.1 70.6 69.3 65.3 Patients (%) N= MVC + CBV EFV + CBV Includes all patients who received at least one dose of study medication MERIT Study 48 weeks <400 copies/mL<50 copies/mL –3.0* (–9.5 † ) –4.2* (–10.9 † ) *Difference (adjusted for randomization strata) † Lower bound of 1-sided 97.5% confidence interval; noninferiority margin = –10% Per-protocol analysis: <400 copies/mL difference = -4.1 (-10.5 † ), <50 copies/mL difference = -4.4 (-11.2 † ) Intent-to-treat (ITT) analysis

7. 7 Mean Change in CD4+ Count from Baseline by Visit Time (weeks) EFV + CBV MVC + CBV Mean change in CD4+ count from baseline (cells/mm 3 ) MERIT Study 48 weeks LOCF 142 cells/mm 3 169 cells/mm 3 N =331346348348348348348348348348 N =336350351352352352352352352352 Includes all patients who received at least one dose of study medication

8. 8 Mean Change in CD4+ Count from Baseline to Week 48 Mean change in CD4+ count from baseline (cells/mm 3 ) LOCF EFV + CBV N=348 MVC + CBV N=352 144 170 0 50 100 150 MERIT Study 48 weeks *Difference: +26 (95% CI: +7, +46) 200 Includes all patients who received at least one dose of study medication * Difference adjusted for randomization strata

9. 9 Percentage of Patients with HIV-1 RNA <50 copies/mL by HIV-1 RNA at Screening 0 10 20 30 40 50 60 70 80 90 100 211 204150 156 71.6 69.6 66.6 59.6 Patients (%) N= Includes all patients who received at least one dose of study medication MERIT Study 48 weeks <100,000 copies/mL≥100,000 copies/mL Missing values classified as failures/non-responders MVC + CBV EFV + CBV

10. 10 Percentage of Patients with HIV-1 RNA <50 copies/mL by Geographic Region 10 20 30 40 50 60 70 80 90 100 199 194162 166 67.868.0 71.0 62.1 Patients (%) N= Includes all patients who received at least one dose of study medication MERIT Study 48 weeks Northern Hemisphere*Southern Hemisphere † Missing values classified as failures/non-responders MVC + CBV EFV + CBV *Patients at study centers in North America and Europe † Patients at study centers in Argentina, South Africa and Australia 0

11. 11 Safety Analyses All causalities and severitiesEFV + CBV N=361 MVC + CBV N=360 Patients with adverse events340 (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) Malignancies16 (4.4)10 (2.8) Deaths † *, n (%)11 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 Includes all patients who received at least one dose of study medication MERIT Study 48 weeks

12. 12 Incidence of Adverse Events Occurring in ≥10% of Patients in Any Group, Unadjusted for Exposure Includes all patients who received at least one dose of study medication MERIT Study 48 weeks MVC + CBV (N=360) EFV + CBV (N=361) Patients (%) 0 10 20 30 40 50 Headache Cough Bronchitis Vomiting Nausea Fatigue Abdominal pain Upper resp. tract infect. Diarrhea Abnormal dreams Nasopharyngitis Rash Dizziness

13. 13 Incidence of Category C AIDS-Defining Events Number of patients EFV + CBV N=361 MVC + CBV N=360 Category C events12 (3.3)6 (1.7) Infections8 (2.2)5 (1.4) Tuberculosis81 Herpes simplex11 Lobar pneumonia/Lower respiratory tract infection 02 Pneumocystis jiroveci pneumonia 01 Malignancies4 (1.1)1 (0.3) Hodgkin’s disease20 NHL/Diffuse large B-cell lymphoma11 Kaposi’s sarcoma10 Includes all patients who received at least one dose of study medication MERIT Study 48 weeks

14. 14 Median Maximum Change in Fasting Lipids Total cholesterol HDL cholesterol LDL cholesterol Triglycerides 1 27 4 9 -3 10 -4 10 -5 0 5 10 15 20 25 30 Median change (mg/dL) MVC + CBV EFV + CBV N= 332 321 327 319 318 311 332 321 MERIT Study 48 weeks

15. 15 Proportion of Patients with Grade 3 or 4 Liver Function Test Values Without Regard to Baseline All causalities, n (%) Unadjusted for duration of exposure EFV + CBVMVC + CBV AST: Grade 3 >5.0 to 10.0 ULN* Grade 4 >10.0 x ULN* 9/350 (2.6%) 2/350 (0.6%) 7/353 (2.0%) 5/353 (1.4%) ALT: Grade 3 >5.0 to 10.0 ULN* Grade 4 >10.0 x ULN* 9/350 (2.6%) 2/350 (0.6%) 9/353 (2.5%) 2/353 (0.6%) Total bilirubin: Grade 3 >2.5 to 5.0 x ULN* Grade 4 >5.0 x ULN*0/345 3/352 (0.9%) † 0/352 *Upper limit of normal † All three patients had hyperbilirubinemia not associated with transaminase elevations, two associated with Gilbert’s syndrome. MERIT Study 48 weeks

16. 16 Summary of 48-Week Primary Analyses (1) ● The percentage of subjects discontinuing from the study prior to Week 48 was similar in the MVC (26.9%) and EFV (25.2%) arms – The rate of discontinuation due to lack of efficacy was higher with MVC (11.9%) than with EFV (4.2%) – The rate of discontinuation due to adverse events was lower with MVC (4.2%) than with EFV (13.6%) ● Based on the pre-planned statistical analysis (noninferiority margin of –10%), MVC was: – Noninferior to EFV based on <400 copies/mL endpoint (70.6% vs 73.1%) – But not the <50 copies/mL endpoint (65.3% vs 69.3%) ● CD4+ cell count increases were higher in patients receiving MVC compared to EFV (+170 vs +144 cells/mm 3 ) MERIT Study 48 weeks

17. 17 Summary of 48-Week Primary Analyses (2) ● Fewer patients experienced grade 3 or 4 adverse events in the MVC arm than in the EFV arm ● Fewer patients experienced Category C events in the MVC arm (n=6) than in the EFV arm (n=12) – The incidence of AIDS-defining malignancies and malignancies in general was lower in the MVC arm than in the EFV arm ● Grade 3/4 transaminase elevations were infrequent and occurred at a similar rate in the two treatment arms ● Median lipid increases from baseline were greater in the EFV arm MERIT Study 48 weeks

18. 18 Acknowledgements ●Patients participating in the MERIT study ●Investigators and study site staff ●Pfizer MERIT study team ●Monogram Biosciences