LAUSR

141 Background: The first and second interim analyses (IA1 and IA2) of the LATITUDE study in NDx-HR mCNPC pts with addition of AA+P to ADT vs placebo (PBO)+ADT showed significant benefit in the coprimary endpoints of overall survival (OS) and radiographic progression free survival (rPFS), and secondary endpoints. Final OS analysis and updated safety results are presented. Methods: 1,199 pts were randomized (1:1) to AA (1 g QD) + P (5 mg QD) + ADT or PBO + ADT. Primary endpoint of OS and secondary endpoints were assessed (stratified proportional hazards model), and adverse events (AEs) were summarized from final analysis, which was planned for around 852 total death events. Results: Final analysis was conducted after a median follow-up of 51.8 mo (~22 mo from IA1) and 618 deaths were observed (275 [46%] in AA+P and 343 [57%] in PBO). Treatment was ongoing for 157 (26.3%) pts in AA+P; 72 (12.0%) crossed over from PBO to AA+P, of which 59 (81.9%) remained on treatment. AA+P treatment continued to show significant OS benefits vs PBO (HR: 0.7, 95% CI: 0.6-0.8; p<0.0001), along with significant improvements in secondary endpoints (table). Serious AEs were reported in 32.2% pts in AA+P and 25.1% in PBO. Grade 3/4 AEs of special interest (AA+P vs PBO; %) were hypertension (21.9 vs 10.5), hypokalemia (11.7 vs 1.7), hepatotoxicity (8.9 vs 3.5), cardiac disorders (3.9 vs 1) and fluid retention (0.8 vs 1). Conclusions: The final analysis continues to demonstrate a significant OS advantage of combining AA+P to ADT in NDx-HR mCNPC pts. These efficacy findings and AE profiles are consistent with IA1 and IA2 and reinforce AA+P as a standard of care in NDx-HR mCNPC pts. Clinical trial information: NCT01715285. [Table: see text]