Wyeth has suffered a double-dose of bad news after the US drug major said it is pulling its European application for Pristiq to treat hot flushes, while a Phase III trial of the bowel drug methylnaltrexone missed its primary endpoint in Phase III trial.

The company said it has voluntarily withdrawn its application for European marketing authorisation for Pristiq (desvenlafaxine) for the treatment of vasomotor symptoms, or hot flushes, associated with menopause. The move has been prompted by the need to conduct additional clinical studies to address questions from the Committee for Medicinal Products for Human Use regarding the drug’s risk-benefit profile in this indication.

Gary Stiles, chief medical officer at Wyeth, said the firm “remains committed to developing the molecule for this indication,” noting that some of the questions raised by the CHMP can be addressed with our planned clinical trials”, including the 12-month study Wyeth is initiating with post-menopausal women. It is also considering whether to conduct additional studies.”

Pristiq, a derivative of the firm’s blockbuster Effexor (venlafaxine), was approved by US Food and Drug Administration for major depressive disorder earlier this month. Last July the agency only issued an approvable letter for Pristiq as a treatment for the symptoms of menopause.

Methylnaltrexone late-stage study fails
Meantime, Wyeth and partner Progenics Pharmaceuticals have been hurt by disappointing late-stage data from a trial of their investigational bowel drug methylnaltrexone.

The firms announced preliminary findings from the first of two Phase III trials of intravenous methylnaltrexone being evaluated for the management of postoperative ileus in patients recovering from segmental colectomy surgical procedures. The data showed that the treatment did not achieve the primary endpoint of a reduction in time to recovery of gastrointestinal function (time to first bowel movement) as compared to placebo.

Additionally, the 542-patient study did not show that secondary measures of surgical recovery, including time to discharge eligibility, were superior to placebo. Wyeth noted that results from a second Phase III trial of the drug are expected by the middle of 2008.

Despite the results, Robert Ruffolo, president of R&D at Wyeth, said “we remain confident in the methylnaltrexone development programme”. Progenics chief executive Paul Madden stated that the firm is conducting “the necessary analyses to determine greater clarity regarding the outcome of this clinical study," adding that the findings are inconsistent with results from a 65-patient Phase II study.

Wyeth’s bad day saw the firm’s shares slip 2.4% to $40.65 but Progenics stock took a huge hit, falling 63.6% to $4.93.