Proscar, Avodart, Jalyn and Propecia will all bear new warnings that they could increase the risk of high-grade prostate cancer, an aggressive form of the disease. The new warnings, to be included in the “Warnings and Precaution” sections of the drugs’ labels, are based on the U.S. Food & Drug Administration’s (FDA) review of two large studies that indicated that men taking finasteride (the active ingredient in Proscar and Propecia) and dutasteride (an active ingredient in Avodart and Jalyn) were more likely to develop aggressive prostate tumors, even though their risk of less serious prostate cancer was reduced.
One of the trials reviewed by the FDA, the Prostate Cancer Prevention Trial (PCPT), followed more than 18,000 men aged 55 or over for up to seven years who were treated with either finasteride or a placebo. While the men in the finasteride group had a 26% overall lower risk of being diagnosed with prostate cancer when compared to the placebo arm, the reduced risk was due mainly to a reduction in low-grade cancers. There was, however, an increase with high-grade prostate cancers with finasteride versus placebo (1.8% versus 1.1%, respectively), the FDA said.
The second trial, Reduction by Dutasteride of Prostate Cancer Events (REDUCE), compared dutasteride with placebo. It followed more than 8,000 men aged 50-75 for four years. The results of the REDUCE trial showed that men on dutasteride had a 23% overall lower risk of being diagnosed with biopsy detectable prostate cancer when compared to men on placebo, but again this was due to a reduction in low-risk tumors. In contrast, there was an increased incidence of high-grade cancers with dutasteride versus placebo (1% versus 0.5%, respectively).
Based on these two studies, the FDA ordered drug makers to modify the “Warnings and Precautions” sections of the labels of all the drugs in this class – 5-alpha reductase inhibitors, or 5-ARIs – to include new information that they may increase the risk of high-grade prostate cancer. The product labeling will also state that 5-ARIs are not approved for the prevention of prostate cancer.
Proscar, Avodart and Jalyn are all used to treat enlarged prostate, while Propecia is used to treat male pattern hair loss.