Wyeth’s bid to get approval for Viviant as a treatment for osteoporosis has foundered as US regulators declined to give the compound the thumbs-up yet again.

The US Food and Drug Administration has issued its third approvable letter for Viviant (bazedoxifene), a selective oestrogen receptor modulator, for the treatment of postmenopausal osteoporosis. Wyeth noted that the agency has requested more information “similar to that outlined” in an approvable letter issued in December 2007, including more analyses about the incidence of stroke and venous thrombotic events.

The FDA has also identified “specific questions concerning data collection and reporting” and requested additional source documents. Nevertheless, Wyeth is not downhearted and chief medical officer Gary Stiles said that the move “is in line with our expectations”.

He added that “in our conference with the agency earlier this year, they stated their desire to convene an advisory committee to review the pending new drug applications for both treatment and prevention of postmenopausal osteoporosis”. It will take a while to address the FDA’s questions, Dr Stiles said, noting that “we are preparing a complete response which we expect to file by end of 2008”.

This means a further delay in Wyeth’s efforts to get approval for Aprela, a combination of conjugated oestrogens and bazedoxifene, which would be used to reduce hot flushes. The firm believes that Aprela, which is positioned as a new form of multifunctional menopausal therapy called tissue selective oestrogen complex, could bring in sales of $2 billion a year.

Deal signed with Indian CRO
Meantime, Wyeth is also teaming up with GVK Biosciences, India’s leading contract research organisation, “to discover drug candidates focused on pre-defined discovery targets”. Under the terms of the deal, the Hyderabad-based firm will receive an initial undisclosed upfront fee, as well as payments based on the achievement of certain research milestones.