Session: Poster Session: Antiretroviral Therapy: New Agents
Sunday, October 26, 2008: 12:00 AM
Room: Hall C
Background: PRO 140 potently inhibits CCR5-tropic (R5) HIV in vitro. In a prior study, single 5mg/kg IV doses reduced HIV RNA by 1.83 log10 in subjects with early-stage disease and R5 virus only. The present study compared 5mg/kg and 10mg/kg IV doses for antiviral activity and tolerability. Methods: Entry criteria included HIV RNA >5,000 copies/mL, R5 virus only, CD4 >300/μL, and no antiretroviral therapy for 12 weeks. Subjects were randomized to receive placebo, 5mg/kg PRO 140 or 10mg/kg PRO 140. They were followed for 58 days post-treatment. An interim analysis was performed on data from the first 15 subjects. Results: Interim enrollment was equally distributed across the treatment groups. Baseline HIV RNA and CD4 averaged 35,480 cps/mL and 403/μL, respectively. Mean maximum log10 reductions in HIV RNA were 0.48 (range 0.15-0.73) for placebo, 1.90 (range 1.44-2.17, p<0.0001) for 5mg/kg PRO 140 and 2.17 (range 2.09-2.26, p<0.0001) for 10mg/kg PRO 140. At Day 12, mean log10 changes in HIV RNA were +0.06, -1.88 (p<0.0001), and -2.01 (p<0.0001) for placebo, 5mg/kg and 10mg/kg, respectively. The mean viral load reduction was >1.5 log10 through Day 22 at 10mg/kg. PRO 140 was generally well tolerated. Trial enrollment has completed, and updated data will be presented. Conclusions: The data confirm the antiviral activity reported previously for 5mg/kg PRO 140. A 10mg/kg dose increased the duration of antiviral effect. The findings indicate the potential for infrequent IV dosing. SC dosing regimens are also being evaluated.
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