Phase II Study of Bipolar Androgen Therapy and Nivolumab in Prostate Cancer
Posted: Wednesday, July 14, 2021
A study presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting found that bipolar androgen therapy (BAT) plus nivolumab was well tolerated and produced a durable response in some patients with metastatic castration-resistant prostate cancer (Abstract 5014). According to Mark Christopher Markowski, MD, PhD, of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, and colleagues, the combination therapy met the prespecified primary endpoint (confirmed decrease in prostate-specific antigen of at least 50%; PSA 50) in this heavily pretreated patient population.
This phase II, multicenter trial enrolled 45 men with metastatic castration-resistant prostate cancer who had experienced disease progression on at least one prior novel androgen receptor targeted therapy. Almost half (44.4%) of patients had received prior taxane therapy. Patients received 400 mg of intramuscular testosterone cypionate (BAT) every 28 days for 12 weeks as lead-in therapy, followed by 400 mg of BAT plus 480 mg of intravenous nivolumab every 28 days. Luteinizing hormone-releasing hormone agonist treatment was continued as well.
The confirmed PSA 50 response rate was 40% in this cohort. The objective response rate was 23.8% among patients with measurable disease. Median radiographic progression-free survival on the study regimen was estimated at 5.7 months, and 11.1% of men (5 of 45 patients) did not have radiographic disease progression for 11 or more months. One patient achieved a complete radiographic response, and this response is ongoing for more than 13 months. Researchers noted that patients had serial biopsies for further translational studies including biomarker analysis.
Most of the adverse events seen as a result of the combination therapy were grade 2 or less. The most common adverse events included edema (20%), nausea (20%), and back pain (13%). Immune-related adverse events were also generally mild (less than grade 2), and two patients experienced grade 3 immune-related side effects (pericarditis, lipase elevation).
Disclosure: For a full list of authors’ disclosures, visit coi.asco.org.