The US pharmaceutical company received an approvable letter from the US Food and Drug Administration (FDA) last month stating Pristiq would not be approved as a treatment for menopausal hot flashes until Wyeth conducted an additional clinical trial to resolve concerns about adverse cardiovascular and hepatic effects associated with the drug in that indication.
As a result of this letter, analysts forecast that Pristiq may now not be approved as a treatment for depression.
The company was also issued with an "expected" approvable letter in January for Pristiq as a treatment for depression, which stated that approval would be subject to a number of conditions, including concerns with the Puerto Rico manufacturing facility.
In a conference call yesterday, executives were positive about working towards getting Pristiq onto the market and stood by their beliefs the drug was an important addition to the healthcare industry.
The executives also claimed they did not believe the heart and liver conditions experienced in some women trialing Pristiq for menopause were associated with the drug.
"We believe Pristiq is a safe, effective and much-needed non-hormonal therapy [for menopause]", Wyeth chief financial officer Greg Norden said.
Women who experienced cardiovascular problems already had pre-existing heart disease, officials said.
There were also no findings of an increased risk of cardiovascular problems in the patients who were taking Pristiq for depression.
Despite Wyeth's claims, the company now has to conduct a randomized, placebo-controlled clinical trial of a duration of one year or more in postmenopausal women.
Executives estimated the additional trial would take at least 18 months to complete.
"Wyeth remains committed to the development of Pristiq as a potential treatment for moderate-to-severe vasomotor symptoms associated with menopause," Wyeth executive vice president and chief medical officer Gary Stiles said in a statement.
"We will work with the agency to satisfy its requests for additional data and move the medicine forward in the FDA review process."
Meanwhile during the conference call, Norden said the company believed Pristiq would receive approval for treating depression in the first quarter of 2008, and the company had been assured by FDA officials the Pristiq for menopause symptom treatment setback would not affect approval of Pristiq for depression.
This would be important for the company considering Pristiq for the treatment of depression is being touted as the next drug to take over from Wyeth's top-selling antidepressant Effexor (venlafaxine) which looses patent protection in 2010.
Wyeth intends to submit its complete response to the depression approvable letter at the end of this month, with the FDA expected to act on the application during the first quarter of 2008.
If Pristiq is approved for the treatment of hot flashes, it would be the first non-hormonal medicine on the market for the treatment of vasomotor symptoms associated with menopause.
