FDA approval for Pristiq (I'll refer to it as Pq occasionally) is contingent upon Wyeth's handling of "quality control problems… made to the satisfaction of federal inspectors." As I'd previously mentioned before, Wyeth has built an amazingly similar medication based on Effexor. Wyeth is trying to market Pristiq as an antidepressant and treatment for vasomotor symptoms (hot flashes during menopause). Wyeth is significantly banking on Pristiq since their $3.5 billion Effexor XR will lose its patent in a few years, allowing other companies to make venlafaxine generics.
Some of the "quality control" problems Wyeth is experiencing:
- unclear whether Pq keeps depressive episodes at bay
- efficacy at low doses and in young kids
- severe nausea in 50 percent of patients in the clinical trials
Reuters' article notes this, though:
"But the studies do not need to be completed prior to approval of the new depression pill."
While Wyeth has admitted that Pq is "structurally related" to Effexor, it "has not yet disclosed if Pristiq has any advantages over Effexor XR, other than to say it would be an alternative to existing treatments."
But it has acknowledged the newer drug caused nausea in about one-half of patients in clinical trials.
Wyeth is banking on patients sticking out the nausea for one week (it supposedly subsides after that) or a 50 mg pill that would be more effective than the whopping 400 mg they used in earlier phases of the clinical trials.
"The company said it will not launch Pristiq until it obtains results from the low-dose trials. Moreover, Wyeth said the timing of the launch also will depend on progress of the FDA's ongoing review of Pristiq as a possible non-hormonal treatment for hot flashes. The FDA is scheduled to decide on the hot flashes indication in April."
Wyeth wants to be absolutely sure they can cover all of their bases in an effort not to lose a single portion on their market share — from those who can tolerate low doses at 50 mg to those who need to go 400 mg and up.
"A G Edwards analyst Joseph Tooley has predicted Pristiq will garner annual sales of $1.4 billion by 2011 — about $1 billion from use against depression and the remainder for menopausal symptoms."
Getting not only psychiatrists to prescribe the drug, but also OB/GYNs is a clever move on their part.