Cardiovascular morbidity in a randomized trial comparing GnRH-agonist and antagonist among patients with advanced prostate cancer.

5015 Background: Androgen-deprivation therapy (ADT) used in prostate-cancer may increase risk of cardiovascular disease (CVD). Limited preclinical and retrospective clinical data suggest that use of gonadotrophin-releasing hormone (GnRH)-antagonist may be associated with lower risk of CVD compared to GnRH-agonist. Methods: We conducted a randomized open-label study comparing the one year incidence of major cardiovascular and cerebrovascular event (MACCE) in prostate-cancer patients with pre-existing CVD commencing on GnRH-agonists or antagonists. Patients were followed every 3 months for the development of MACCE defined as either death, myocardial infarction (MI), cerebrovascular event (CVA), or percutaneous-coronary intervention (PCI). Serum levels of N-terminal pro-B-type natriuretic peptide (NTproBNP) were analyzed at baseline, 3, 6 and 12-months. Results: Eighty patients were enrolled (41 randomized to GnRH-antagonist, 39 to GnRH-agonist). Patients in both arms had similar age, baseline cardiovascular and prostate-cancer characteristics. During follow-up 15 patients developed a new cardiovascular event. Of these, nine patients developed MACCE (two deaths, one MI, two CVAs, and four PCI). Twenty percent (n = 8) of patients randomized to GnRH-agonists had a MACCE compared to 3% (n = 1) randomized to antagonists (log-rank p = 0.013). The absolute risk reduction for MACCE at 12 months using GnRH-antagonist was 18% (95%CI 5-31). Baseline levels of NTproBNP predicted events (AUC = 0.73 95%CI 0.54-0.91 p = 0.03) and increased over time only among patients with CV events. Conclusions: This is the first prospective study to test cardiovascular outcome among prostate-cancer patients receiving ADT. We demonstrated that in patients with pre-existing CVD, GnRH-antagonists was associated with development of fewer cardiovascular events compared to GnRH-agonists. Clinical trial information: NCT02475057.