Comparative Cardiovascular Safety of Gonadotropin-releasing Hormone Antagonists and Agonists Among Patients Diagnosed with Prostate Cancer: A Systematic Review and Meta-analysis of Real-world Evidence Studies

Background and objective: Gonadotropin-releasing hormone (GnRH) antagonists and agonists are cornerstone treatments in prostate cancer. However, evidence regarding the comparative cardiovascular safety of these drugs from clinical trials is inconclusive. The objective of this study was to systematically assess the risk of adverse cardiovascular events of GnRH antagonists compared with GnRH agonists across real-world evidence studies.

Methods: We conducted a systematic search of PubMed, Embase, Cochrane Library, Scopus, and Web of Science (2008-2023). We included real-world evidence studies comparing the risk of cardiovascular outcomes of GnRH antagonists with those of GnRH agonists among patients with prostate cancer. We conducted a meta-analysis of effect estimates across studies at a low or moderate risk of bias, assessed via the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) tool, using random-effect models.

Key findings and limitations: Among ten included studies, four were classified as having a moderate and six as having a serious risk of bias. Across three studies at a moderate risk of bias in the primary analysis, degarelix was associated with an increased risk (pooled relative risk [RR]: 1.31, 95% confidence interval [CI]: 1.14-1.51) of major adverse cardiovascular events (MACEs). An augmented risk was observed in two studies among patients with a history of cardiovascular disease (pooled RR: 1.31, 95% CI: 1.11-1.56) compared with one study among patients without a history of cardiovascular disease (RR: 1.15, 95% CI: 0.83-1.59).

Conclusions and clinical implications: Real-world evidence studies indicate that degarelix, compared with GnRH agonists, is associated with a modest increased risk of MACEs, particularly among patients with a history of cardiovascular disease. However, residual confounding due to the treatment of high-risk patients with degarelix may account for these findings. Additional large studies with detailed data on tumor characteristics and cardiovascular risk factors are needed to confirm these findings.

Patient summary: In this systematic evaluation of evidence among patients diagnosed with prostate cancer in routine care, degarelix was associated with higher cardiovascular adverse outcomes than gonadotropin-releasing hormone agonists.