Preliminary 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.
Should the new formulation be successful, the companies could file a new drug application for oral methylnaltrexone as early as late 2009 or early 2010.
Methylnaltrexone is being developed in subcutaneous and oral forms to treat opioid-induced constipation and an intravenous form for post-operative ileus, a prolonged dysfunction of the GI tract following surgery.
“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,” said Robert Ruffolo Jr, senior vice president for Wyeth.
The companies remain on track to submit a new drug application in March for the subcutaneous form in the palliative care setting and for the intravenous form in late 2007 or early 2008.