GSK’s Avodart may slow prostate cancer’s progress, study says

GlaxoSmithKline (NYSE:GSK) is not giving up finding a role for enlarged prostate drug Avodart as a prostate cancer treatment.

A study published today in The Lancet suggests that Avodart, also called dutasteride, could slow prostate cancer’s progression in men who have low-risk prostate cancer under active surveillance. But an editorial also published today in The Lancet disagrees with the conclusions of the GSK-funded study.

British drugmaker GSK, which has its U.S. headquarters in Research Triangle Park, North Carolina, had been trying to expand Avodart’s approval beyond the BPH indication. Avodart works by blocking enzymes that promote prostate growth. The drug shrinks the prostate and relieves symptoms that include frequent and difficult urination. Research into dutasteride as a male-pattern baldness drug was abandoned after phase 2 clinical trials.

Through the third quarter of 2011, Avodart generated $873 million in revenue; $390 million of those sales coming from the United States. Avodart will lose its U.S. patent protection in 2015. The company has already had to take steps to fend off generics preparing to enter the market. A new indication for the drug could help sustain Avodart sales beyond patent expiration. But a year ago, GSK’s application to add prostate cancer prevention as a new indication was quashed in a complete response letter from the U.S. Food and Drug Administration. Last March, GSK announced it would no longer pursue marketing authorization for Avodart to reduce the risk of prostate cancer.

Risk reduction was not the objective of the study results published today. The study, a three-year, randomized, placebo-controlled study involved 302 men already diagnosed with low-risk prostate cancer who had chosen to follow up with active surveillance. Researchers reported that 38 percent of the men in the dutasteride group had prostate cancer progression. By comparison, 48 percent of participants in the control group had prostate cancer progression. The researchers’ interpretation of the study data is that dutasteride “could provide a beneficial adjunct to active surveillance for men with low-risk prostate cancer.

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