CytoDyn Inc. announced the company has received approval from the United States Food and Drug Administration (FDA) to commence patient screening of a Phase 2b study of PRO 140, a monoclonal CCR5 antibody, for the treatment of patients with Human Immunodeficiency Virus Type 1 (HIV-1). The Phase 2b study is being conducted by Drexel University College of Medicine and funded by grants from the National Institutes of Health (NIH). PRO 140 Phase 2b study is a multicenter, randomized, double-blind, placebo-controlled, clinical trial of observed systemic, long-acting, anti-HIV treatment with PRO 140 as an adjunct to an optimized oral antiretroviral regimen in HIV-infected injection drug users with viral rebound and documented poor adherence to the previous antiretroviral regimen.

The primary study objective will be to assess the antiviral effects, tolerability and patient acceptance of PRO 140 or placebo administered subcutaneously weekly for 24 weeks in combination with an optimized background oral antiretroviral regimen. PRO 140 belongs to a new class of HIV/AIDS therapeutics -- viral-entry inhibitors -- that are intended to protect healthy cells from viral infection. PRO 140 is a humanized monoclonal antibody directed against CCR5, a molecular portal that HIV uses to enter cells.

PRO 140 has been the subject of four Phase 1/1b and two Phase 2a clinical trials, each of which demonstrated PRO 140's ability to significantly reduce HIV viral load in human test subjects, and has also been designated a 'fast track' product candidate by the United States Food and Drug Administration. The PRO 140 antibody appears to be a powerful antiviral agent while not being a drug, leading to potentially fewer side effects and less frequent dosing requirements as compared to daily drug therapies currently in use.