FDA: 5-alpha-reductase inhibitors may increase high-grade PCa risk

June 23, 2011

The FDA is informing health care professionals that the "Warnings and Precautions" section of the labels for the 5-alpha-reductase inhibitor class of drugs has been revised to include new safety information about the increased risk of being diagnosed with high-grade prostate cancer, although the risk appears to be low.

The FDA is informing health care professionals that the “Warnings and Precautions” section of the labels for the 5-alpha-reductase inhibitor class of drugs has been revised to include new safety information about the increased risk of being diagnosed with high-grade prostate cancer, although the risk appears to be low.

The FDA said the new safety information is based on its review of two large, randomized controlled trials––the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial––which evaluated daily use of finasteride (Proscar), 5 mg, versus placebo for 7 years and daily use of dutasteride (Avodart), 0.5 mg, versus placebo for 4 years, respectively, for the reduction in the risk of prostate cancer in men at least 50 years of age. The trials demonstrated an overall reduction in prostate cancer diagnoses with finasteride and dutasteride treatment. This overall reduction was due to a decreased incidence of lower risk forms of prostate cancer. However, both trials showed an increased incidence of high-grade prostate cancer with finasteride and dutasteride treatment.

The FDA said physicians should also be aware of the following:

  • Prior to initiating therapy with 5-ARIs, perform an appropriate evaluation to rule out other urologic conditions, including prostate cancer, that might mimic BPH.
  • Treatment with 5-ARIs causes an approximate 50% reduction in PSA values by 6 months; however, individual patients receiving 5-ARIs may experience varying decreases in PSA values. Therefore, any confirmed increase in PSA while on a 5-ARI may signal the presence of prostate cancer and should be evaluated, even if that PSA is in the normal range of men not taking a 5-ARI.
  • 5-ARIs are not approved for the prevention of prostate cancer.