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New Targeted Drug Improves Prostate Cancer Survival

Among men with metastatic, hormone-refractory prostate cancer, treatment with the investigational drug MDV3100 delayed cancer progression and improved overall survival. These results will be presented at the 2012 Genitourinary Cancers Symposium.

Prostate cancer is a hormonally sensitive disease that can be controlled for long periods with androgen deprivation therapy (ADT). When prostate cancer stops responding to this treatment, it is referred to as hormone-refractory prostate cancer. Advances have been made in the treatment of hormone-refractory cancer, but challenges remain and new drugs continue to be developed.

MDV3100 is an investigational drug with a new approach to hormonal therapy. The drug interferes with the ability of male hormones to bind to their receptors within a cell, and also reduces the ability of the receptors to enter the nucleus and stimulate cell growth.

To evaluate the safety and efficacy of MDV3100 in the treatment hormone-refractory prostate cancer, researchers conducted a Phase III clinical trial known as AFFIRM. The study enrolled 1,199 men with metastatic, hormone-refractory prostate cancer. All of the men had experienced a worsening of their cancer in spite of previous treatment with hormonal therapy and the chemotherapy drug Taxotere® (docetaxel). Study participants were treated with either MDV3100 or a placebo (sugar pill).

At the time of an initial analysis part way through the study, researchers found that MDV3100 had significantly improved overall survival: median overall survival was 18.4 months among men treated with MDV3100 and 13.6 months among men treated with placebo. As a result of this benefit, the study was stopped early, and men in the placebo group were offered MDV3100.
MDV3100 was also found to delay cancer progression: survival without cancer progression was roughly 8 months among men in the MDV3100 group and 3 months among men in the placebo group.
MDV3100 was generally well tolerated. The most common side effects were fatigue, diarrhea, and hot flushes.

This study suggests that MDV3100 improves outcomes among men with metastatic, hormone-refractory prostate cancer. MDV3100 is also being evaluated for the treatment of earlier stages of prostate cancer.

Reference: Scher HI, Fizazi K, Saad F et al. Effect of MDV3100, an androgen receptor signaling inhibitor (ARSI), on overall survival in patients with prostate cancer postdocetaxel: Results from the phase III AFFIRM study. Presented at the 2012 Genitourinary Cancers Symposium. February 2-4, 2012.San Francisco,CA. Abstract LBA1.