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671 Background: Immune checkpoint inhibitors (ICIs) demonstrate impressive clinical benefit across a variety of cancers. NCCN guidelines for several cancers including renal cell carcinoma now support ICI monotherapy and combination therapy with ipilimumab. Cardiac toxicity is a rare but catastrophic adverse event associated with ICIs. We sought to define the comparative cardiac risk profile of ICI combination versus monotherapy in a real world setting. Methods: We used VigiBase, the World Health Organization database of case safety reports, which collects data from more than 130 countries to identify drug-associated adverse events. Using Medical Dictionary for Regulatory Activities terminology, we identified cardiac adverse events (AE) related to monotherapy (nivolumab, ipilimumab, pembrolizumab) or combination therapy (ipilimumab/nivolumab). To explore a possible relationship we used the reporting odds ratio (ROR), a surrogate measure of association using all other reactions as non-cases. A lower bound of a 95% confidence interval of ROR > 1 reflects a disproportionality signal that more AEs are observed than expected due to chance. Results: We found 7,644, 25,016, and 14,681, and 5,191 AEs for ipilimumab, nivolumab, pembrolizumab, and combination therapy respectively. No signal existed for overall cardiac events, but combination therapy was associated with significantly higher odds of pericarditis or myocarditis (ROR 6.9, 95% CI 5.7—8.3) versus pembrolizumab (5.6, 4.9—6.4), nivolumab (5.1, 4.6-5.7), or ipilimumab monotherapy (1.9, 1.4-2.7). Pericarditis and myocarditis with combination therapy was fatal for 23% of reported AEs, compared to 14%, 14%, and 20% for ipilimumab, nivolumab, and pembrolizumab (p = 0.003) respectively. Conclusions: Using validated pharmacovigilance methodology, we found significantly increased odds of myocarditis and pericarditis for all ICI, with the highest odds for combination therapy. These adverse events were often fatal. Further research is needed to identify patients at high risk for immunotherapy related cardiac toxicity.

34 Background: Gonadotropic releasing hormone (GnRH) agonists and antagonists are first-line for advanced prostate cancer, but may be associated with cardiac toxicity. Observational studies show a relatively lower risk for GnRH antagonists, but a randomized trial found no difference. We compared the reporting of cardiac events for GnRH agonists and antagonists. Methods: We used VigiBase, the World Health Organization global database of case safety reports, which collects data from more than 130 countries to extract drug-adverse event (AE) pairs. Using Medical Dictionary for Regulatory Activities terminology, we identified AEs related to GnRH antagonist (degarelix) or agonist (leuprolide, goserelin, triptorelin, histrelin) therapy for prostate cancer, including myocardial infarction, heart failure, cardiomyopathies, new-onset valvular dysfunction, and other major cardiac events. To explore a possible relationship we used the reporting odds ratio (ROR), a surrogate measure of association using all other reactions as non-cases. A lower bound of a 95% confidence interval of ROR > 1 reflects a disproportionality signal that more AEs are observed than expected. Results: We found 10,504 AEs for GnRH agonists, and 1,606 for GnRH antagonists; 805 (7.7%) were cardiac for agonists, and 102 for antagonists (6.4%). We found no signal for overall cardiac events or any subgrouping for GnRH antagonists, but identified a signal both for overall cardiac events (ROR 1.20, 95% CI 1.12-1.29) and myocardial infarction (1.76, 1.57-1.97) for GnRH agonists. Conclusions: Using validated pharmacovigilance methodology, we found a signal for myocardial infarction for GnRH agonists, but did not detect one for GnRH antagonists. As cardiovascular disease is the most common cause of non-cancer death in prostate cancer patients, this finding is of specific relevance in the current era of novel second-line anti-androgen therapies which may compound toxicity when added to first-line therapy. The relative cardiac toxicity of GnRH agonist therapy compared to GnRH antagonists merits renewed attention.

70 Background: The standard of care for advanced prostate cancer is androgen deprivation therapy (ADT). The novel second generation agents abiraterone and enzalutamide were initially approved in castration resistant disease, but are now being used in the hormone sensitive setting. The FDA issued a 2010 warning about cardiovascular risks associated with ADT, but the risk of novel agents is less well understood, especially in comparison to each other. We sought to define the comparative cardiac risk profile of enzalutamide and abiraterone. Methods: We used VigiBase, the World Health Organization database of individual case safety reports, which collects data from more than 130 countries to identify drug associated adverse events (AE). Using Medical Dictionary for Regulatory Activities terminology, we identified cardiac AEs related to abiraterone or enzalutamide therapy for prostate cancer. To explore a possible relationship we used the reporting odds ratio (ROR), a surrogate measure of association using all other reactions as non-cases. A lower bound of a 95% confidence interval of ROR > 1 reflects a disproportionality signal that more AEs are observed than expected due to chance. Results: Vigibase contained 8203 AEs for abiraterone and 26024 for enzalutamide; 808 (9.9%) were cardiac-related for abiraterone, and 1000 for enzalutamide (3.8%). We found no disproportionality signal for cardiac events or any subtype for enzalutamide, but identified significantly higher odds of overall cardiac events (ROR 1.64, 95% CI 1.53—1.76), myocardial infarction (1.34, 1.17—1.58), arrythmia (2.09, 1.87—2.34), and heart failure (3.35, 2.92—3.85) for patients taking abiraterone. Conclusions: Using validated pharmacovigilance methodology, we found significantly increased odds of cardiac events for abiraterone but not for enzalutamide. Clinicians may need to consider these findings in the context of their patients’ comorbidities when prescribing ADT.