Progenics and Wyeth initiate safety trial for opioid inhibitor

Methylnaltrexone could be a breakthrough treatment for the bowel condition as there are no medicines currently approved for POI. Methylnaltrexone has received Fast Track designation from the FDA. Fast Track facilitates development and may accelerate regulatory review and is often given to drugs that are seen by the FDA as serving an unmet medical need.

The cause of POI is not clear, but stimulation of naturally found opioids receptors in response to the trauma of surgery is believed to be involved. The problem can be exacerbated by the administration of drugs, such as morphine, to relieve post-operative pain.

Methylnaltrexone is designed to reverse certain peripheral side effects caused by opioids, particularly in the gastrointestinal tract, while not interfering with brain-centered pain relief.

“Post-operative medications are often administered intravenously, as patients have difficulty tolerating oral medications following surgery. Therefore, methylnaltrexone in an intravenous form would be a convenient route of administration in this setting,” aid Ann Lowry, President of the American Society of Colon and Rectal Surgeons

In a pilot phase II clinical trial previously conducted by Progenics, patients who received methylnaltrexone following segmental colectomy exhibited improvements in clinically important measures of gastrointestinal recovery.

“Opioid use for post-operative pain relief can delay or prolong surgical recovery,” said Robert Israel, Progenics' senior vice president, Medical Affairs. “Intravenous methylnaltrexone is designed to target an underlying cause of post-operative ileus, the unwanted interaction of opioids with the gastrointestinal tract. Our studies will evaluate the ability of methylnaltrexone to accelerate bowel recovery after surgery.”

Subsequent to completion of these studies, a new drug application is planned for late 2007 or early 2008.