While data on the heart and stroke risks oftestosterone enhancers have been mixed, the FDAhas held firm on its position that "Low T" drugs should be used only for medical conditions and not as a lifestyle drugs. Now the FDA says drugmakers need to provide new data on the heart and stroke risks of using them to boost testosterone in aging men. But, to save everybody a lot of time, effort and cost, it would be great if the drugmakers would do the clinical trial work together.

The argument for that is laid out in a piece appearing in Thursday's issue of theNew England Journal of Medicine, according to Medscape. In the piece, penned by Dr. Christine Nguyen, a deputy director of Safety in the FDA's office of drug evaluation, and other experts, experts point out that while there has been a big increase in the use of the drugs to treat older men whose sex drive has waned, the benefits and risks of doing that have not been determined. In the piece, the authors encourage "companies to work together on a single trial."

Aggressive marketing by drugmakers has been generally believed to be behind the fact that prescriptions for the drugs grew by 1 million, to 2.3 million between 2009 and 2013. Most of those new users were men taking it for age-related issues. Troubling, the FDA has said, since nearly 30% of those prescriptions were written without serum testosterone concentration testing even being done.

The FDA has looked at a couple of metadata and other studies, but the populations in each were different and the findings mixed. The agency in March told drugmakers it wanted them to add to labels info about potential heart attack and stroke risks, and advised docs not to prescribe the drugs for age-related symptoms. That came after an advisory panel last year voted 14-1 to restrict testosterone-replacement therapies to men with a related medical condition such as a tumor or genetic disorder.

Even ahead of the FDA call for laying out the risks, AbbVie ($ABBV), which makesAndrogel, and Eli Lilly ($LLY), maker of Axiron, had reported waning sales for their products and said investors could expect further declines in sales. Neither company Thursday responded to requests for comment on whether they would consider working with competitors on a study looking at the drug risks.

- here's the Medscape Multispecialty story (reg. req.)
- here's the NEJM story (sub. req.)
- more from WebMD