Broadening the use of two prostate drugs into cancer prevention didn't win a thumbs-up from FDA's expert advisors. After weighing the arguments over the last couple of days, the advisory committee voted against adding a cancer-prevention indication to GlaxoSmithKline's ($GSK) Avodart--and against adding cancer-prevention data to the label on Merck's ($MRK) Proscar.
Both approved to treat enlarged prostate, the two drugs have shown some efficacy at preventing--or at least holding off temporarily--less aggressive forms of prostate cancer. But study data also suggested a possible increase in aggressive tumors in men who used the drugs for that purpose. The companies and researchers blamed the increase on improved detection: Shrinking the prostate significantly makes tumors easier to find, they said.
But the advisory panel wasn't impressed. According to the New York Times, the FDA committee said there's too much uncertainty about long-term consequences, especially if blessing the prevention data broadened use significantly--and to a new population of patients. "Hundreds of thousands of people will be exposed to these drugs," FDA's oncology chief Dr. Richard Pazdur said (as quoted by the Times). "This is not an oncology drug that is going to be prescribed by a select group of medical oncologists."
The FDA could make a different determination; though the agency usually follows its advisory committees' recommendations, it doesn't always. But it may be persuaded by the committee's argument that preventive drugs have to reach a higher safety standard, compared with treatments used to treat actual cancers. We'll have to wait and see.