Methylnaltrexone, an oral tablet for opioid-induced constipation (OIC) by Progenics, will soon undergo late stage clinical studies.
Progenics Pharmaceuticals, Inc plans to commence a phase 2b/3 clinical trial of a methylnaltrexone tablet in chronic-pain patients in the second half of 2010, the company said in a press release.
The study of the methylnaltrexone tablet was conducted in subjects with chronic, non-cancer pain receiving various opioid treatment regimens.
Study data suggest that oral methylnaltrexone is active and generally well tolerated.
Onset of action and the percentage of patients who had responded within four hours are consistent with that previously shown in clinical trials of subcutaneous methylnaltrexone.
“We believe that the activity demonstrated to date by the methylnaltrexone tablet shares the hallmarks of methylnaltrexone: both a prompt onset of action and a predictable response for a large percentage of patients,” stated Paul J. Maddon, M.D., Ph.D., founder, chief executive officer and chief science officer of Progenics.
The tablets to be used in Progenics’ planned phase 2b/3 trial were produced by Wyeth at Wyeth’s cost as provided for under the provisions of the termination of the collaboration between the two companies.
Opioids are considered to be effective analgesics for the management of moderate-to-severe pain, and one of the most common side effects of opioids is constipation.
Opioids provide pain relief by specifically interacting with mu-opioid receptors within the central nervous system (CNS) – the brain and spinal cord.
However, opioids also interact with mu-opioid receptors found outside the CNS, such as those within the gastrointestinal tract, resulting in constipation that can be debilitating.
The tablet form of oral methylnaltrexone was developed by Progenics’ former collaboration partner Wyeth.
However, Progenics regained from Wyeth the rights to methylnaltrexone, including rights to this methylnaltrexone tablet at the time of Wyeth’s acquisition by Pfizer in October 2009.
The transfer of data and information to Progenics regarding Wyeth’s work on oral methylnaltrexone was recently completed and Progenics has now had the opportunity to review in detail information regarding the methylnaltrexone tablet which is being reported on today.
Methylnaltrexone selectively displaces opioids from the mu-opioid receptors outside the CNS, including those located in the gastrointestinal tract, thereby decreasing their constipating effects.
Because of its chemical structure, methylnaltrexone does not affect the opioid-mediated analgesic effects on the CNS.
Relistor (methylnaltrexone bromide), administered via subcutaneous injection, is a peripherally acting mu-opioid receptor antagonist that decreases the constipating effects of opioid pain medications in the gastrointestinal tract without affecting their ability to relieve pain.
In April of 2008, the U.S. Food and Drug Administration approved Relistor subcutaneous injection for the treatment of opioid-induced constipation (OIC) in patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient.
The use of Relistor beyond four months has not been studied. Relistor is now approved in over 40 countries, including the U.S., Canada, the European Union, Latin American countries and Australia. Other applications in additional countries are also pending.
Progenics Pharmaceuticals, Inc., of Tarrytown, NY, is a biopharmaceutical company focusing on the development and commercialization of innovative therapeutic products.
Progenic’s Principal programs are directed toward supportive care, oncology and virology.
Relistor is now approved in over 40 countries, including the U.S., Canada, the European Union, Latin American countries and Australia.
Progenics is pursuing strategic alternatives for Relistor, including licensing, collaboration, strategic alliances and U.S. commercialization or co-promotion, following termination of its 2005 collaboration with Wyeth Pharmaceuticals, which is continuing manufacturing, sales, marketing, and certain development and regulatory activities for RELISTOR during the transition.
Ono Pharmaceutical Co., Ltd. has an exclusive license from Progenics for development and commercialization of subcutaneous Relistor in Japan. In oncology, the Company is conducting a phase 1 clinical trial of a human monoclonal antibody-drug conjugate (ADC) for the treatment of prostate cancer–a selectively targeted chemotherapeutic antibody directed against prostate-specific membrane antigen.
PSMA is a protein found on the surface of prostate cancer cells as well as in blood vessels supplying other solid tumors.
Progenics is also conducting phase 1 clinical trials with vaccines designed to treat prostate cancer by stimulating an immune response to PSMA in immunized subjects.
Progenics is also developing novel multiplex PI3-Kinase inhibitors as a potential strategy to combat some of the most aggressive forms of cancer. In virology, Progenics is developing the viral-entry inhibitor PRO 140, a humanized monoclonal antibody which binds to co-receptor CCR5 to inhibit human immunodeficiency virus (HIV) infection.
PRO 140 is currently in phase 2 clinical testing. The company’s hepatitis C virus discovery program seeks to identify novel inhibitors of HCV entry.