Wyeth and Progenics Begin Phase II Trial of Oral Methylnaltrexone

Wyeth Pharmaceuticals and Progenics Pharmaceuticals, Inc. (Tarrytown, New York) have begun a phase II clinical trial to evaluate once-daily dosing of oral methylnaltrexone, a peripheral mu opioid-receptor antagonist designed to reverse the effect of opioids on opioid receptors outside the central nervous system, thus reducing opioid-induced constipation. The trial is designed to identify the dose(s) of methylnaltrexone to be taken forward into the phase III studies.