CytoDyn Inc., a biotechnology company focused on the development of new therapies for combating human immunodeficiency virus (HIV) infection, has initiated its first phase 3 study for PRO 140, the company's novel self-injectable antibody for the treatment of HIV.
The company's phase 3 protocol provides for a 25-week study with 300 HIV-positive patients. Selection of clinical sites, IRB approvals, patients screening and other administrative matters are underway and are expected to be completed in time for the first patient to be dosed in the third quarter of this year.
The company believes that upon successful completion of this phase 3 study, CytoDyn will have the opportunity to seek accelerated approval for PRO 140 based on the previously FDA granted fast-track candidate designation. Additionally, CytoDyn may apply for a "breakthrough" designation for PRO 140, as the first self-injectable antibody for HIV therapy.
The company's first phase 3 study is designed to allow PRO 140 as a component of a HAART (Highly Active Anti-Retroviral Therapy) regimen for treatment experienced patients. HAART is the current standard of medical care for individuals with HIV. Management believes the market size for a HAART therapy, which includes the PRO 140 antibody, along with other potential PRO 140 indications, could exceed a billion dollars. CytoDyn believes that its PRO 140 antibody, which targets the CCR5 co-receptor, has compelling advantages over Maraviroc, the only other CCR5 antagonist approved for HIV therapy. These advantages include less toxicity, fewer side effects and once-a-week versus daily administration, which together may improve patient compliance.
The FDA is in agreement with CytoDyn's proposed regulatory path for the first approval for PRO 140 and the company plans to request a meeting with the FDA to discuss potential additional indications for HIV therapy with PRO 140 following the submission of the "top-line report" of the recently completed phase 2b treatment substitution study.
Dr. Nader Pourhassan, president and chief executive officer, commented: "CytoDyn is proud to have developed the first self-injectable antibody for the treatment of HIV by reaching this substantial Phase 3 milestone on the path to approval. The FDA has been helpful in guiding us to define the preferred regulatory path for our first approval and we plan to explore a label-expansion path with the FDA shortly after this study starts."
Dr. Pourhassan added: "Only about 20 per cent of the HIV population in the US have a completely suppressed viral load. The rate of transmission of HIV increases by over 99 per cent when the viral load is not suppressed. PRO 140 has been recognized by the NIH and FDA as a product that can potentially address the challenges faced by patients suffering from HIV. We believe the FDA's prior designation of PRO 140 as a candidate for fast track approval speaks volumes about its potential. We are very pleased to have advanced PRO 140's development into a phase 3 trial in just a few short years and are optimistic about its future to improve the lives of people suffering from HIV."
“To maintain the company's aggressive approach on moving PRO 140 expeditiously through this phase 3 study, CytoDyn recently signed a new contract with Amarex Clinical Research, LLC, as its CRO, to manage this phase 3 trial. “Amarex has done a remarkable job for us with our recently completed Phase 2b study and we are very happy to continue forward with them for our Phase 3 trial," said Dr. Pourhassan.
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 fully humanized IgG4 monoclonal antibody directed against CCR5, a portal that HIV uses to enter T-cells. PRO 140 blocks the predominant HIV (R5) subtype entry into T-cells by masking this required co-receptor, CCR5. Importantly, PRO 140 does not appear to interfere with the normal function of CCR5 in mediating immune responses. PRO 140 has been the subject of seven clinical trials, each demonstrating efficacy by significantly reducing or controlling HIV viral load in human test subjects. PRO 140 has 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.
Fast track is a process designed to facilitate the development and expedite review of drugs and biologics intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. An important feature of fast track is that it emphasizes the critical nature of close early communication between the FDA and sponsor to improve the efficiency of product development.
A breakthrough therapy is a drug intended alone or in combination with one or more other drugs to treat a serious or life threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. If a drug is designated as breakthrough therapy, FDA will expedite the development and review of such drug. All requests for breakthrough therapy designation will be reviewed within 60 days of receipt, and FDA will either grant or deny the request.