WYETH, PROGENICS BEGIN STUDY OF ORAL METHYLNALTREXONE

Wyeth Pharmaceuticals and Progenics Pharmaceuticals announced that Wyeth is beginning Phase III clinical testing of a new formulation of oral methylnaltrexone for the treatment of opioid-induced constipation. Originally, results from the Phase II trial conducted by Wyeth showed that the initial formulation of oral methylnaltrexone was generally well tolerated but did not exhibit sufficient clinical activity to advance into Phase III testing.

Methylnaltrexone is being studied as a treatment for the peripheral side effects of opioid analgesics. It is designed to mitigate the effect of opioids on the peripheral receptors without interfering with brain-centered pain relief.

The drug is being developed in subcutaneous and oral forms to treat opioid-induced constipation and an intravenous form for postoperative ileus. The companies remain on track to submit a new drug application (NDA) this month for the subcutaneous and intravenous forms in late 2007 or early 2008. Should the new oral formulation be successful, the companies could file an NDA as early as late 2009 or early 2010.

"Both the subcutaneous and intravenous formulations of methylnaltrexone have shown a high degree of activity in clinical trials. Therefore, the companies believe that the findings from the oral trial appear to be due to the orally administered formulation tested rather than the methylnaltrexone compound itself," Robert Ruffolo, president of Wyeth Research, said.