ASCO GU to Spotlight Prostate Cancer Drugs MDV3100 and Radium-223

The 2012 Genitourinary Cancers Symposium, to be held Feb. 2-4, will feature potentially practice-changing data on two novel agents – MDV3100 and radium-223 chloride – in prostate cancer.

• Results of the phase III AFFIRM trial, to be reported in full Feb. 2, show that the investigational oral androgen–receptor signaling inhibitor MDV3100 prolongs overall survival in progressive castration-resistant prostate cancer after failure of docetaxel (Taxotere).

Men given this agent lived on average nearly 5 months longer than their counterparts given a placebo, according to a press preview of data by the American Society of Clinical Oncology (ASCO). There was no increase in rates of grade 3 or higher adverse events or serious adverse events with MDV3100. The rate of seizures was 0.6% with the drug and 0% with placebo.

• Results of the placebo-controlled phase III ALSYMPCA trial show that the first alpha-particle–emitting drug to target bone, radium-223 chloride (Alpharadin), prolonged overall survival by nearly 3 months (prompting early trial closure) and delayed the time to skeletal-related events by about 5 months in men with bone-only metastatic castration-resistant prostate cancer who had received or were not candidates for docetaxel.

Radium-223 chloride was well tolerated, and there were no cases of leukemia. The U.S. Food and Drug Administration has granted Fast Track status to this investigational agent.

In addition, two large observational studies using linked Surveillance, Epidemiology, and End Results (SEER) and Medicare data, will likely add to the debate regarding the most cost-effective treatment for prostate cancer, and in particular, the pros and cons of various radiation therapy options.

• Investigators at the University of North Carolina at Chapel Hill and University of North Carolina Hospitals will report findings in more than 12,000 men with localized prostate cancer, showing a lower rate of subsequent cancer treatment with intensity-modulated radiation therapy (IMRT) vs. conformal radiation therapy; bowel toxicity and hip fracture were less common with the former, whereas erectile dysfunction was less common with the latter. In addition, proton therapy did not yield a significantly lower rate of subsequent cancer treatment vs. IMRT, and also had a higher rate of bowel toxicity.

• Investigators at the Cleveland Clinic and Kaiser Permanente will report outcomes after a median follow-up of 71 months in 137,427 men with prostate cancer of various stages, showing that of three common therapies – prostatectomy, external-beam radiation therapy (EBRT), and brachytherapy – EBRT was associated with the highest cumulative incidences of gastrointestinal and genitourinary therapy–related toxicity necessitating intervention and also was the most costly.

In another study of note, also being reported in full Feb. 2, researchers will present findings regarding the impact of vigorous exercise on gene expression in the prostate gland that may help explain its benefit in reducing progression.

• This study in a low-risk prostate cancer population under active surveillance has found that a set of 184 genes in normal prostate tissue are differentially expressed between men who exercise vigorously at least 3 hours a week and men who exercise less intensively, according to results to be presented in a poster session. A number of tumor suppressor genes were upregulated in the vigorous exercisers, and pathway analysis showed that the DNA repair and cell cycle pathways were positively modulated.

For ongoing coverage of these and other presentations at the ASCO Genitourinary Cancers Symposium, visit The Oncology Report.