Ian Davis, MBBS, PhD, FRACP, FAChPM

Although ARCHES was a positive trial, the results may not signal a practice change at this time, according to formal discussant Ian Davis, MBBS, PhD, FRACP, FAChPM, of Monash University Eastern Health Clinical School, Melbourne. “We should probably not change practice yet on the basis of these results, although a clear survival signal would change my opinion,” he said.

“In order to change practice, a study should have a meaningful endpoint, the drug should have acceptable toxicity that does not compromise efficacy of subsequent treatments, and it should be cost-effective,” Dr. Davis said. “But current therapies work well and are cost-effective, so a high bar should be set for new treatments.”

“We now have evidence of benefit in meta-static hormone-sensitive prostate cancer when conventional androgen-deprivation therapy (ADT) is supplemented by docetaxel or abiraterone, now enzalutamide as well, or apalutamide although those results have not yet been presented. Clinicians and patients have several choices. Health-care system and financial constraints may mean it is timely to look carefully at the comparative cost effectiveness of these drugs. Additionally, we do not yet know whether combinations of these agents add additional benefit and such treatment should not yet be given outside a clinical trial ,” Dr. Davis stated.

Howard I. Scher, MD

Speaking from the audience, Howard I. Scher, MD, of Memorial Sloan Kettering Cancer Center, New York, pointed out that the populations in the studies of these different drugs are not matched and have some differences, suggesting that it is difficult to compare them based on study data. Regarding a direct comparison of drugs added to ADT earlier in the course of prostate cancer, Dr. Scher commented, “I like the idea of a horse race, but whether it can happen, I’m not sure.” ■

DISCLOSURE: Dr. Davis has received institutional research funding from Astellas Pharma, Roche/Genentech, MSD Oncology, AstraZeneca, Eisai, Pfizer; Janssen Oncology and patents/royalties/other intellectual property through Ludwig Institute for Cancer Research; and is chair of ANZUP Cancer Trials Group. Dr. Scher has had a leadership role with Asterias Biotherapeutics.