5046 Background: The value of continuation of androgen deprivation therapy (ADT) in metastatic castration-resistant prostate cancer (CRPC) remains controversial and clear evidence is lacking. Especially upon treatment with the life-prolonging cytochrome P450 17-alpha-hydroxylase/C17,20 lyase (Cyp17)-inhibitor, abiraterone acetate (AA), which in combination with prednisone (P), has the ability to further suppress serum testosterone levels over ADT alone, continuation of ADT seems to be negligible. Methods: The exploratory phase II trial randomized CRPC patients to receive continued ADT plus AA+P versus AA+P alone (NCT02077634), funded by Jansen-Cilag GmbH, Germany. The primary endpoint was rate of rPFS at month 12, not powered for a direct comparison between treatment arms. Secondary endpoints included PSA response rate, objective response, time to PSA progression and safety. Results: Altogether, 67 patients were randomized between 08/2014 to 04/2017. Median testosterone-levels (T) remained far below castrate-levels throughout treatment in all patients. However, in 6 patients (18%) from Arm B, T-levels increased above castrate levels within 28 days after cessation of AA+P treatment. Median treatment duration is shorter in Arm A. Safety analysis is underway and results will be presented. Conclusions: Results of this exploratory study suggest that treatment with AA+P without ADT may be effective in patients with mCRPC and that ADT may not be necessary in patients receiving AA+P. In some patients, serum-testosterone levels may rise rapidly upon treatment discontinuation so that the levels should be monitored closely. Clinical trial information: NCT02077634. [Table: see text]

Androgen deprivation therapy is an integral part of the treatment of advanced and progressive prostate cancer. Various prospective randomised trials have investigated whether or not temporary suspension of androgen deprivation might delay the emergence of castration resistant prostate cancer and concomitantly improve quality of life. Until now, no phase III trial has been able to prove that intermittent androgen deprivation might delay the development of castration resistant tumours. Data from previous trials, except for one study, did at least not show adverse effects on survival. Data on quality of life are inconsistent, showing a trend towards improved quality of life with IAD. German as well as European guidelines reflect IAD as an established constituent of day-to-day medical practice. This review is intended to provide a code of practice for an individualised treatment as based on recently published studies.

219 Background: ADT is an established part of the guideline-oriented therapy of prostate cancer (PCa). Concerns regarding increased CV risks associated with ADT were raised by the FDA in 2010. Results from a pooled data-analysis of six prospective randomised trials suggest a lower number of CVevents in patients treated with the GnRH antagonist Degarelix compared with GnRH agonist treated patients with preexisting cardiovascular disease [Albertsen P. et al: Eur Urol 2014; 65: 565-73]. Objective: Can SHI data confirm the observation that the risk for CVevents varies depending on the substance used for ADT. Methods: Retrospective data sets of 4 Mio assured people from SHI funds from the years 2009-2012 were analysed to identify PCa patients treated with ADT, GnRH agonists and GnRH antagonists, respectively. An age-adjusted reference group with 1.1 Mio non-PCa persons was identified in the data sets. Results: 44.166 patients suffering from PCa were identified. Of those 10.611 patients were treated with ADT. 10.554 with GnRH agonists and 132 with GnRH antagonists, respectively. An increased prevalence for relevant baseline CV diseases was observed in ADT treated patients compared to the Non-PCa reference group (diabetes mellitus: 28.66% vs 17.43%.; CAD: 35.77% vs 15.70%; Heart failure: 27.54% vs 9.64%). The rate of heart attack and stroke (CVevents) after treatment begin with ADT was determined: 2.37% in the reference group, 5.9% in the PCa group, 7.8% in the ADT group, 2.3% in the GnRH antagonist group. All CVevents in GnRH antagonist group occurred in high risk patients, only. The urologist examined and reported the state of CV risk for 25% of the PCa patients, only. Urologists examine and treat statistically significantly more patients with a combination of PCa and CVevents than general practitioners (30 vs. 5 per year/per physician). Conclusions: This retrospective analysis confirms the hypothesis that the risk of CVevents varies by using different ADT. The risk might be lower by using GnRH antagonists. A close collaboration of urologists, general practitioners and cardiologists is therefore recommended in the management of PCa patients.

232 Background: In addition to the radical prostatectomy and radiotherapy, androgen deprivation therapies (ADT) have been established as a therapy option in patients with high-risk localized and metastatic prostate cancer (PCa). ADT was found to be associated with a higher risk for cardiovascular (CV) events. This retrospective claims-based study investigated whether CV event rates differ following initiation of ADT with gonadotropin-releasing hormone (GnRH) agonists or antagonists and PCa patients not treated with ADT. Methods: Analyses were based on claims data from the research database of the Health Risk Institute. Eligibility criteria included a PCa diagnosis between 2009 and 2013 and the initiation of ADT with GnRH agonists or antagonists or no ADT during follow up. Outcomes of interest included a composite endpoint of myocardial infarction (MI) or ischemic stroke (IS) as well as the occurrence of a CV event. The latter included MI, sequelae of cerebrovascular disease, IS, intracerebral hemorrhage, pulmonary embolism, phlebitis/thrombophlebitis, transient cerebral ischemic attacks and occlusion/stenosis of cerebral arteries. Results: ADT patients suffered from more comorbidities, were older, and were more likely to suffer from CV conditions than patients with no ADT during baseline. Patients treated with GnRH agonists and antagonists were comparable in terms of mean age and burden of comorbidities. The raw event rates for MI/IS and for CV events during follow up were higher in ADT patients than in patients without ADT (Table 1). Patients treated with GnRH agonists suffered more often from a CV event during follow-up than patients treated with antagonists. Conclusions: Our results indicate that ADT with GnRH antagonists is associated with fewer CV events in PCa patients than treatment with GnRH agonists. The results confirm findings from a pooled analysis of six phase III randomized controlled trials (Albertsen P. et al: Eur Urol 65 (2014) 565-573.). [Table: see text]