New treatment for HIV

CytoDyn announces 100-percent success with PRO 140 in four-week monotherapy clinical trial

Lloyd Dunlap
VANCOUVER, Wash.—CytoDyn Inc., a biotechnology company focused on the development of new therapies for combating infection with human immunodeficiency virus (HIV), today announced the continuation of strong positive results for four weeks of monotherapy with its monoclonal antibody, PRO 140, in patients with HIV-1, who are currently participating in the company's Phase 2b treatment substitution trial. CytoDyn has requested an "end of Phase 2b meeting" with the U.S. Food and Drug Administration (FDA) to discuss Phase 3 plans.

This Phase 2b clinical study was designed to investigate the potential of allowing patients to enjoy treatment interruption from their current HAART regimen concurrent with a monotherapy consisting of weekly injections of PRO 140. The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs in an attempt to control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life-cycle. The use of multiple drugs that act on different viral targets is known as highly active antiretroviral therapy (HAART). HAART decreases the patient's total burden of HIV, maintains  function of the immune system, and prevents opportunistic infections that can lead to death.

The results from the treatment substitution trial to date have demonstrated 100-percent success in suppressing the viral load among patients who had weekly injections of PRO 140 for four weeks of monotherapy. Success was defined as zero virologic failures. The company is requesting FDA clearance to conduct a larger similar Phase 3 licensing trial to demonstrate further the efficacy of PRO 140 for four weeks of monotherapy with PRO 140.

The complete trial results to date from all 40 patients (including the first and second cohorts) are: As of October 13, 2014, there were zero virologic failures among 21 patients who have reached four weeks of monotherapy and among 36 patients out of 40 who have received at least the first injection of PRO 140.

Comparing these results with previous studies used as historical controls supports the current study's successful outcome. In a 37-patient trial of treatment interruption from HAART, approximately 50 percent of patients experienced viral load breakout before four weeks and approximately 100 percent showed viral load breakout at eight weeks. In another similar study, results indicated that 10 of 12 patients experienced viral load breakout after just 2 weeks of treatment interruption from HAART.

Dr. Nader Pourhassan, CytoDyn president and CEO, commented: "We believe this is a very strong indication that PRO 140 is effective to allow four weeks of drug holiday with weekly injections. PRO 140's safety has been well documented in previous studies, as well as our current study. Moreover, PRO 140's 100-percent efficacy rate for four weeks of treatment substitution provided our technical team with the confidence to recommend that we seek FDA approval for a patient-care program of four weeks of drug holiday with weekly injections of PRO 140. We are very encouraged with our progress in 2014 and firmly believe the company is well positioned to make a significant contribution to current treatments of HIV patients."

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 its ability to significantly reduce HIV viral load in human test subjects, and has also been designated a Fast Track product candidate by the FDA. The PRO 140 antibody appears to be a powerful antiviral agent leading to potentially fewer side effects and less frequent dosing requirements as compared to daily drug therapies currently in use.

CytoDyn is a biotechnology company focused on developing subcutaneously delivered humanized cell-specific monoclonal antibodies (mAbs) as entry inhibitors for the treatment and prevention of Human Immunodeficiency Virus (HIV). The company’s PRO-140 is one of the leading mAbs under development for HIV infection. PRO 140 blocks the HIV co-receptor CCR5 and clinical trial results thus far indicate that it does not affect the normal function of the cell. Results from Phase 1/1b and Phase 2a human clinical trials have shown that PRO 140 can significantly reduce viral burden in people infected with HIV. CytoDyn intends to continue to develop PRO 140 as a therapeutic anti-viral agent in persons infected with HIV.

Lloyd Dunlap

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