Treating Opioid-Induced Constipation

Wyeth Pharmaceuticals in conjunction with Progenics Pharmaceuticals, Inc. is studying methylnaltrexone bromide which goes by the trademarked name RELISTOR. The drug, administered as a subcutaneous injection, is intended to treat constipation brought on by taking opioid painkillers. The phase III clinical trial has so far achieved similar positive results to those seen in the earlier studies. The results have been issued from the portion of the phase III trial that is double-blind, randomized, and placebo-controlled.

Disrupted Lives

Wyeth Pharmaceuticals’ Executive Vice President and Chief Medical Officer Gary L. Stiles, M.D., reports, ” Many patients who take prescription opioids to help relieve their non-cancer pain experience opioid-induced constipation, which can disrupt their lives. The results of this study suggest that RELISTOR has the potential to help decrease the constipating effects of opioids for this patient population.”

The two parties, Wyeth and Progenics, have plans to sit with officials from regulatory bodies such as the United States Food and Drug Administration (USFDA) to go over the newly generated data and will also present the results of their trials at soon-to-take place scientific conferences.

Significant Improvement

Paul J. Maddon, M.D., Ph.D., speaking for Progenics Pharmaceuticals, Inc. as Founder, Chief Executive Officer, and Chief Science Officer said, “This phase 3 clinical study of RELISTOR subcutaneous injection showed statistically significant improvements in the occurrence of bowel movements in patients with opioid-induced constipation who have chronic, non-cancer pain.”

In the most recent phase of the study, RELISTOR or a placebo were given by subcutaneous injection for one month. The goal of this phase was to determine what percentage of patients receiving the drug had bowel movements within four hours and how many bowel movements were experienced within the course of a week. The research was undertaken in 80 centers throughout the United States and Canada with 469 participants. The patient participants all had a confirmed history of opioid-induced constipation (OIC). All the patients are in treatment with opioid medications for chronic pain due to such varied conditions as fibromyalgia syndrome, nerve pain, osteoarthritis, back trouble and other types of pain not resulting from cancer.

As many as 10 million Americans are prescribed opioids for a period of a month or more, every year, for managing pain. While opioids are effective pain-killers for treating moderate or severe chronic pain, they have unpleasant side effects, among them, chronic constipation. RELISTOR has already received approval for treating OIC in patients suffering from advanced illnesses where laxatives have not been effective.