NCI Cancer Bulletin for February 22, 2011 - National Cancer Institute: Dutasteride May Slow the Growth of Early-Stage Prostate Cancer

Dutasteride May Slow the Growth of Early-Stage Prostate Cancer

For men who are undergoing active surveillance for early-stage prostate cancer, the drug dutasteride (Avodart) could help control the disease and prevent the need for more aggressive treatments. The finding, from a randomized, placebo-controlled trial, was presented during the 2011 Genitourinary Cancers Symposium, which was held February 17–19 in Orlando, FL. Dutasteride is already approved by the Food and Drug Administration (FDA) for the treatment of an enlarged prostate gland, or benign prostatic hyperplasia.

Active surveillance, previously called “watchful waiting,” refers to the practice of forgoing immediate treatment after a prostate cancer diagnosis in favor of regularly scheduled testing and clinical exams to closely monitor the disease. In the Reduction by Dutasteride of Clinical Progression Events in Expectant Management (REDEEM) trial, 302 men undergoing active surveillance were randomly assigned to receive either dutasteride, which belongs to the class of drugs known as 5-alpha reductase inhibitors, or placebo for 3 years. Biopsy specimens were collected at 18 and 36 months, or as warranted based on evidence of disease progression.

In the dutasteride group, 38 percent of the men experienced some progression of their cancer, compared with 49 percent of the men in the placebo group. This difference translated into a reduction in relative risk for cancer progression of 38.9 percent in the dutasteride group. In addition, taking dutasteride increased the chances that no cancer would be found during a participant’s final biopsy. Thirty-six percent of the men in the dutasteride group and 23 percent of the men in the placebo group had no cancer detected in their final biopsy specimens.

It would be “very reasonable” to give a 5-alpha reductase inhibitor to patients with “ultra low-risk” prostate cancer who elect for active surveillance, said the trial’s lead investigator, Dr. Neil Fleshner of the University Health Network in Toronto, during a press briefing. However, Dr. Fleshner cautioned, this would be considered an “off-label” use of dutasteride. In December, the FDA’s Oncologic Drugs Advisory Committee rejected GlaxoSmithKline's application to approve dutasteride for use in preventing prostate cancer, and Dr. Fleshner said that the company was unlikely to seek an additional approval for the drug.

“The results of REDEEM suggest that dutasteride has an antitumor effect against low-volume, low-risk prostate cancer,” said Dr. Howard Parnes of NCI’s Division of Cancer Prevention, who was not involved in the study. “I think that this class of drugs [5-alpha reductase inhibitors] deserves to be studied further in men undergoing active surveillance.”

The Genitourinary Cancers Symposium was cosponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology.

NCI Cancer Bulletin for February 22, 2011 - National Cancer Institute