A panel of advisers to the US Food and Drug Administration last week unanimously rejected an experimental testosterone patch as a treatment for women with sexual difficulties.
Procter & Gamble, global manufacturer of household products, wants to market the patch to women who have become menopausal after ovarian surgery, are currently taking oestrogen, and are said to have a controversial condition—“hypoactive sexual desire disorder.”
The FDA had granted Procter & Gamble a fast track review of the testosterone patch, but the committee's unanimous rejection makes approval by the FDA unlikely until more data on the drug are available.
At a meeting last Thursday, near Washington, DC, panel members strongly criticised the company funded clinical trials as “inadequate” to assess issues of long term safety. Panel members also raised serious concerns about the risks of cardiovascular disease and breast cancer associated with a drug that appeared to offer women, on average, little more than one extra episode of sexual activity a month, compared with placebo.
Panel member Steve Nissen from the Cleveland Clinic said that the testosterone patch's potential to increase cardiovascular risk was substantial: “I don't want to expose several million American women to the risk of myocardial infarction and stroke, with their devastating consequences, in order that they can have one more sexual episode a month,” he said.
None of the data from Procter & Gamble's 24 week randomised controlled trials of the patch have been published yet in peer reviewed journals. Abstracts presented at conferences have claimed repeatedly that the drug is safe and effective and has side effects similar to those of placebo. Yet data presented at last week's FDA meeting showed that women using testosterone were more likely to experience hair growth, acne, and weight gain.
During the course of the highly charged day long meeting, FDA advisers repeatedly questioned Procter & Gamble's officials and the company's paid academic consultants about the clinical meaningfulness of the drug's small benefits, the lack of long term data, and the scientific uncertainties that surround the link between testosterone concentrations and sexual difficulties.
In a 14 to three vote, most of the FDA advisory committee agreed that, although the benefits of the patch appeared to be small, they could be described as “clinically meaningful.” But the committee then voted unanimously to recommend against approving the drug because of the lack of data about its long term safety.
Acknowledging its disappointment, Procter & Gamble says it will work with the FDA and try to provide additional safety data.