FDA Panel Backs Pfizer Osteoporosis Drug

Despite a plethora of safety issues raised by FDA reviewers in their briefing document, an agency advisory committee decided that the benefits of Pfizer's Fablyn outweighs the risks for women past menopause. The panel voted 9-3 with one abstention in favor of Fablyn, which Pfizer developed with Ligand Pharmaceuticals,Reuters writes.

Members felt Fablyn would be most likely to help women at high risk of fractures, according to Sandra Carson, the panel's chairwoman and the director of reproductive medicine and infertility at Women and Infants Hospital of Rhode Island. "The panel felt, overall, women would benefit from having this drug available," Carson told reporters.

Some panelists said Fablyn should be restricted to women who do not tolerate other osteoporosis medicines known as bisphosphonates. The once-a-day tablet may increase the risk of death from cancer or stroke, the FDA reviewers wrote (back story), and it increased the risk of blood clots in Pfizer's studies. Also, more women died while taking a low dose of Fablyn compared with a placebo. A majority of panel members said they were unable to tell if the increase was truly linked to the drug.

In an investor note, Credit Suisse analyst Catherine Arnold writes: "Given the amount of discussion at today’s meeting on the benefit-to-risk ratio for Fablyn, we are not convinced that the FDA will definitely approve the drug, especially when one considers that the FDA has rejected it twice before for other indications.

"If Fablyn is approved this fall (FDA Action Date is October 18), we believe the commercial potential for the drug will be limited given the availability of older bisphosphonates (including generic forms of Merck’s Fosamax) that women will probably be treated with first, as well as Lillly's Evista, which is in the same class as Fablyn and has a much broader indication (treatment and prevention of osteoporosis and reduction in the risk of invasive breast cancer).

"All of the SERMs, including WYE’s Viviant (which is currently under review with the FDA) and LLY’s Arzoxifene (which will be submitted to the FDA in the fourth quarter of 2009), will also be forced to compete for sales with the longer-acting bisphosphonates (Novartis' Reclast) and deal with the potential arrival of Amgen's denosumab to the market in 2010."