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PRO 140
This site is for healthcare professionals. If you are not a health care provider please contact your physician.
HIV
Human Immunodeficiency Virus (HIV) infection has continued to increase around the world, reaching a record 40.3 million people in 2005, including nearly five million new infections. Individuals living with HIV in high-income countries rose to 1.9 million, which includes an estimated 65,000 newly infected patients. Worldwide, there were over three million deaths attributed to AIDS during 2005.
HIV entry
The first step in HIV infecting CD4 cells is mediated through sequential interactions between HIV envelope proteins (Env) and two cellular molecules: CD4 and a co-receptor, typically either CCR5 (R5) or CXCR4 (X4). Acute HIV infection almost always involves virus that binds to the CCR5 coreceptor. During advanced HIV disease, the virus may shift its focus to the alternate CXCR4 receptor, but it has been shown that 50% of virus still binds to the CCR5 coreceptor.
PRO140
We recently completed a phase 1b study of PRO 140 to explore the safety and efficacy of PRO 140 following a single IV dose (0.5-, 2-, or 5-mg/kg) in HIV-1 infected individuals. In May 2007, we announced positive results from this study. In this single-dose study, PRO 140 produced highly significant reductions in viral load and suppressed viral replication for two to three weeks. In HIV-infected individuals who received 5.0 mg/kg of PRO 140, an average maximum decrease of viral load of 1.83 log10 (98.5%; p<0.0001) was achieved. At nine days post-treatment, these same individuals achieved a mean viral load reduction of 1.70 log10 (98%; p<0.0001). In this cohort, mean viral load persisted at or below the 1.0 log10 level of reduction for two to three weeks before returning to baseline at approximately thirty days.
Individual viral load reductions of 2.5 log10 (99.7%) were achieved with the highest dose (5.0 mg/kg).
The response rate (percentage of patients with a ≥ log10 decrease in HIV RNA at any time) among the highest dose cohort was 100% (p<0.0001). No serious adverse events were reported.
PRO 140 has been granted Fast Track designation by the FDA.