PD10-12 CARDIOVASCULAR RISK WITH GNRH AGONISTS AND ANTAGONISTS: REAL-WORLD DATA FROM UK PRIMARY CARE

Abstract

INTRODUCTION AND OBJECTIVE: Androgen deprivation therapy (ADT) is used as a treatment for prostate cancer which aims to reduce serum testosterone to castrate levels. Gonadotrophin releasing hormone (GnRH) agonists are commonly used in combination with an anti-androgen. Alternatively, a GnRH antagonist is available, degarelix, which rapidly suppresses testosterone without the need for antiandrogen therapy. A link between ADT and risk of cardiovascular (CV) events has been reported. The aim of this study was to investigate the use of degarelix and GnRH agonists in the UK, and to compare cardiovascular events following initiation of therapy. METHOD(S): Patients with prostate cancer who were new users of degarelix, leuprorelin, goserelin or triptorelin and registered at a GP practice from 2010 till 2018 were identified from the UK's general practice database (Optimum patient care database). All patients were followed from the index prescription date (IPD) until the date they died, transferred out of the GP, switched to second line treatment, the date of CV event or the end date of data collection, whichever came first. Group differences were analysed with the chi-squared test, Fisher's exact test, Kruskal-Wallis or ANOVA using Bonferroni correction. RESULT(S): From the database, the number of patients with a read code for prostate cancer was 9,081. Of these, 101 were prescribed degarelix, 3289 leuprorelin, 4366 goserelin and 1325 triptorelin. The average age was 75+/-8.5 (mean+/-SD), with an average BMI 27.4+/- 4.6. Patients prescribed degarelix had a significantly higher baseline PSA Vs the GnRH agonists (89.5 ng/ml Vs 17.6 ng/ml, P=0.0028), suggesting these patients had more advanced disease. Significantly more patients prescribed degarelix had pre-existing cardiovascular disease at baseline (ischemic heart disease, heart failure, myocardial infarction or arrhythmia compared to the agonists (37.6% vs 30.4%, P=0.0028). There were no significant differences in other baseline co-morbidities (hepatic impairment, osteoporosis, urticaria, UTI's or diabetes (P>0.05). From the population of patients with prostate cancer treated with ADT, significantly less patients initiated on degarelix had a cardiovascular event (specifically arrhythmia or ischemic heart disease) after initiation of therapy, compared to those patients initiated on a GnRH agonist (6.9% vs 16.8%, P=0.028). CONCLUSION(S): This population-based cohort study suggests patients with previous cardiovascular history and a high baseline PSA are prescribed degarelix compared to a GnRH agonist. Despite a higher CV risk in the degarelix cohort, significantly more patients treated with an agonist had a CV event after initiation of therapy. The data suggests patients with a previous CV event may benefit from initiation on degarelix rather than a GnRH agonist.