Study of PRO 140 SC as Single Agent Maintenance Therapy in Virally Suppressed Subjects With CCR5-tropic HIV-1 Infection

This study is a Phase 2b/3, multi-center study designed to evaluate the efficacy, safety, and tolerability of the strategy of shifting clinically stable patients receiving suppressive combination antiretroviral therapy to PRO 140 monotherapy and maintaining viral suppression for 48 weeks following study entry. Consenting patients will be shifted from combination antiretroviral regimen to weekly PRO 140 monotherapy for 48 weeks during the Treatment Phase with the one week overlap of existing retroviral regimen and PRO 140 at the beginning of the study treatment and also one week overlap at the end of the treatment in subjects who do not experience virologic failure.

The primary objective is to assess the treatment strategy of using PRO 140 SC as long-acting, single-agent maintenance therapy for the chronic suppression of CCR5-tropic HIV-1 infection. In addition, the prognostic factors of therapeutic success of PRO 140 monotherapy will be evaluated. The secondary objective of the trial is to assess the clinical efficacy, safety and tolerability parameters following substitution of combination antiretroviral therapy with weekly PRO 140 monotherapy.