MADISON, N.J., Aug. 22 (UPI) -- Wyeth and Progenics said Tuesday they have launched a phase 2 study of oral methylnaltrexone for opioid-related constipation.
The companies said they would test the drug to treat patients with opioid-induced constipation who are on opioids for chronic pain.
The phase 2 study will assess the appropriate daily dose of the drug to be used in the phase 3 safety and efficacy trial.
The placebo-based phase 2 study will enroll 200 to 400 patients at more than 100 clinical sites in 21 countries. The phase 2 trial is expected to take less than one year, with the phase 3 study getting underway in 2007, the companies said.
Patients treated with opioid analgesic drugs such as morphine for moderate to severe pain often experience constipation as a side effect.
Methylnaltrexone reverses this effect, but without interfering with the opioid drug's ability to relieve pain because methylnaltrexone works outside the central nervous system.
