Groundbreaking results of a trial have shown that the combination of a new drug with androgen deprivation therapy (ADT) significantly improves overall survival (OS) and radiographic progression-free survival (PFS) in patients with high-risk metastatic hormone-naïve prostate cancer, presented at the 22017 ASCO Annual Meeting (June 2-6, 2017; Chicago, IL).
Patients with newly diagnosed metastatic hormone-naïve prostate cancer, especially those with high-risk characteristics, generally have a poor prognosis. ADT plus docetaxel has shown improved outcomes in this population, but many patients are not candidates for docetaxel and would instead benefit from alternative therapy.
Karim Fizazi, MD, PhD, department of medical oncology, Institute Gustave Roussy, and colleagues conducted a phase III, multinational, multicenter, randomized trial to test the effects of ADT in combination with abiraterone acetate plus prednisone in patients with high-risk metastatic hormone-naïve prostate cancer. The LATITUDE study enrolled 1199 newly diagnosed patients; 597 of whom were randomized to receive ADT in combination with abiraterone acetate plus prednisone, while 602 of whom were randomized to receive ADT and placebo. Primary endpoints included OS and radiographic PFS.
Study findings indicated that ADT in combination with abiraterone acetate plus prednisone reduced the risk of death by 38% compared to ADT plus placebo (HR, 0.62; 05% CI, 0.51-0.76; P < .0001). Median OS for patients in the abiraterone acetate plus prednisone arm was not reached, whereas median OS for patients in the placebo arm was 34.7 months.
Additionally, researchers reported that ADT in combination with abiraterone acetate plus prednisone decreased the risk of radiographic PFS by 53% compared to ADT plus placebo (HR, 0.47; 95%CI, 0.39-0.55; P < .0001). Median radiographic PFS for patients in the abiraterone acetate plus prednisone arm was 33.0 months, whereas median radiographic PFS for patients in the placebo arm was 14.8 months.
The ADT in combination with abiraterone acetate plus prednisone arm also met all of its secondary endpoints, including statistically significant improvements in times to pain progression, next subsequent therapy for prostate cancer, initiation of chemotherapy, prostate-specific antigen progression, and symptomatic skeletal events.
“This is important new information, as not all patients respond well to the current standard of care. LATITUDE suggests that abiraterone acetate plus prednisone, in combination with [ADT], can offer a new and much-needed option for patients with high-risk newly diagnosed [metastatic hormone-naïve prostate cancer],” said Dr. Fizazi in a press release (June 3, 2017).
Grade 3/4 adverse events associated with abiraterone acetate plus prednisone included hypertension (20%), hypokalemia (10%), and alanine aminotransferase increase (5%). However, researchers reported that this safety profile was consistent with data from prior studies.—Zachary Bessette