Experimental Entry Inhibitor PRO 140 Wins “Fast Track” Designation from FDA 

Progenics Pharmaceuticals announced that the company’s experimental entry inhibitor PRO 140 has been designated a fast track product by the US Food and Drug Administration (FDA) for the treatment of HIV. The FDA Fast Track Development Program facilitates development and expedites regulatory review of drugs intended to address an unmet medical need for serious or life-threatening conditions.

PRO 140 belongs the entry inhibitor class of anti-HIV drugs, a new class of HIV/AIDS therapeutics that are intended to protect healthy cells from viral infection. Now in Phase 1b clinical trials in HIV-positive individuals, PRO 140 is amonoclonal antibody directed against CCR5, a molecular portal that HIV uses to enter cells. Following is part of a statement released by Progenics on the FDA fast track designation:

"Fast-track status has the potential to accelerate the development of PRO 140," said Paul J. Maddon, MD, PhD, Progenics' Founder, Chief Executive Officer and Chief Science Officer. "Although great strides have been made in HIV treatment, there is an urgent need for the development of new therapies such as PRO 140 to address the limitations of currently available HIV drugs."

With Fast Track designation for PRO 140, Progenics can take advantage of several programs at FDA to streamline the regulatory review process and to work more closely with the Agency on product development plans.

In addition, PRO 140 may be considered for priority review (6-month versus standard 10-month review) as well as accelerated approval. Sponsors of Fast-Track products are also eligible to submit a New Drug Application on a rolling basis, enabling FDA to commence review of sections of the application before receiving a complete application. FDA may also approve a Fast-Track product, if it has an effect on a surrogate endpoint that is likely to predict its clinical benefit.

PRO 140 may represent a new treatment paradigm for HIV patients, because it has the potential to address the limitations of currently available therapies, including the emergence of multi-drug-resistant virus, significant side effects, drug-drug or drug-food interactions, and often-complex daily treatment regimens.

In a recently completed Phase 1 study in healthy volunteers, PRO 140 exhibited dose-dependent binding to CCR5-expressing cells. A single 5 mg/kg dose of PRO 140 significantly coated -- and thereby potentially protected from HIV infection -- CCR5 cells for as long as 60 days. PRO 140 was generally well tolerated at all dose levels in this study.

CCR5 is normally found on certain cells of the immune system and plays a role in inflammatory response. In 1996, Progenics' scientists and their collaborators discovered that HIV uses CCR5 as a portal to enter and infect healthy cells. Blocking this molecular doorway on human cells represents an important new therapeutic strategy.

In laboratory studies, PRO 140 has been found to target a specific site on CCR5 that is utilized by HIV. PRO 140's attachment to this site does not interfere with the normal function of CCR5. PRO 140 has the potential to be broadly active against viruses that have acquired resistance to existing classes of antiretroviral therapies, since none of these drugs targets CCR5.

Progenics is seeking to develop PRO 140 as a new HIV therapy that combines infrequent dosing and a more favorable side effect profile than existing therapies.

Abstract on PRO 140 at 13^th CROI in Denver:

W C Olsen and others. Prolonged Coating of CCR5 Lymphocytes by PRO 140, a Humanized CCR5 Monoclonal Antibody for HIV-1 Therapy. Abstract 515. 13th CROI. February 5-8, 2006. Denver, CO).

02/28/06

Source
Progenics Pharmaceuticals, Inc.