Pfizer's antidepressant Pristiq failed in adolescents

Pfizer today reported its antidepressant Pristiq (desvenlafaxine succinate extended release) in adolescents (7-17 years) with severe depression fail in clinical trials groups, and no significant improvement compared to placebo. This test a total of 363 patient involvement, of which 30 per cent of children aged 7-11. Test consists of three arms, namely the placebo, low dose (equivalent to an adult body weight equivalent to 25 mg daily) and high dose (equivalent to an adult body weight equivalent to 35 mg per day), there was no statistical difference between the results of the efficacy of the three groups.

Pristiq is original Wyeth products, Wyeth was acquired after 2009 became a member of the Pfizer Pfizer product lines. This product has been listed in 2008, but then there are some strings attached. One of the conditions is that Wyeth must follow the requirements of the Equality Act Youth Research do teenagers efficacy in clinical trials. In June this year, another adolescent patients in clinical trials of Pristiq also failed to improve symptoms better than placebo.

Venlafaxine is the first serotonin - norepinephrine reuptake inhibitors, and Prozac but regardless of the molecular structure or mechanism are very similar. Venlafaxine is one of Wyeth's flagship product, so the patent expired in 2010 have developed a new generation product Wyeth Pristiq. Pristiq is the active metabolite of venlafaxine (at least one Class A), so theoretically venlafaxine similar effect. A selling point is the Pristiq than venlafaxine easy to use, because the latter have to have a dose-climbing process. But Pristiq even in clinical trials in adults also general effect, more improvement than placebo only 2-3 points Hamilton index, and high-dose (100 mg) effect disappears. This dose-response relationship, although not impossible, but how much reliability doubtful efficacy.

In view of the above information Pristiq invalid in adolescent patients is not too unexpected. Adolescents and adults are quite different brain, liver and kidney metabolism is also more active, and there are some unknown factors now make many very reliable efficacy in adult drugs among adolescents is invalid. One theory is that these drugs are used to optimize adult animal model, so the success rate is higher than in adult children. But even these animal models of disease for adults is also very unreliable, I highly doubt with minor animal model can significantly improve the success rate of depression in adolescents drugs. A surprising data is that this experiment, 30% of patients are children 7-11 years of age. Age is so small it is unfortunately suffering from severe depression.

CNS field to extend the product with the active metabolite of life is quite common, because there is no reliable way to optimize. Although there is no venlafaxine Pristiq brilliant sales but also a sort of a small product. Today, the results of this test basically blocked the youth market Pristiq entering this road.

( Bolise Co., Ltd. http://www.chemicalspharm.com/ )