The 2019 Annual Meeting of the American Society of Clinical Oncology takes place from May 31 to June 4.
An independent late-stage study of Astellas Pharma Inc.'s and Pfizer Inc.'s treatment Xtandi found that men with prostate cancer lived longer with the drug than with other medicines of the same type, but patients experienced more side effects.
Results from the phase 3 trial named Enzamet, which was led by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group, were unveiled June 2 at the 2019 Annual Meeting of the American Society of Clinical Oncology.
In the study, which enrolled 1,125 patients, 80% of men with metastatic hormone-sensitive prostate cancer who received Xtandi as well as a testosterone-suppressing standard-of-care treatment lived for three years. Of men taking other anti-androgen drugs — including bicalutamide, nilutamide or flutamide — 72% lived for the same amount of time.
However, Xtandi presented more side effects than the other drugs: 42% taking Xtandi had serious adverse events while only 34% of patients on one of the other drugs experienced such problems.
In men who had more serious cases of prostate cancer, 71% survived the three years compared with 64% taking one of the other drugs. In men with less serious cases, 90% were alive at the end of three years compared with 82% on another medicine.
"Physicians and patients with prostate cancer now have a new treatment option with [Xtandi], and this is especially relevant for men who cannot tolerate chemotherapy and have a lower burden of disease seen on scans," said study Co-Chair Christopher Sweeney, a medical oncologist at the Lank Center for Genitourinary Oncology at the Dana-Farber Cancer Institute.
The U.S. Food and Drug Administration approved Xtandi in 2012 in prostate cancer patients who had already been treated with chemotherapy and again in 2014 for patients who had not received treatment.
The 2019 American Society of Clinical Oncology meeting is expected to bring together more than 32,000 professionals from around the world, with more than 2,400 study abstracts to be presented on site and an additional 3,200 abstracts to be published online.