Adjusting Overall Survival Estimates for Treatment Switching in Metastatic, Castration-Sensitive Prostate Cancer: Results from the LATITUDE Study.
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ABSTRACT: BACKGROUND:LATITUDE was the first phase 3 trial examining the survival benefit of adding abiraterone acetate (AA)?+?prednisone (P) to androgen-deprivation therapy (ADT) in newly diagnosed metastatic, castration-sensitive prostate cancer (mCSPC). Due to significant improvement in overall survival after the first interim analysis, patients in the placebos?+?ADT arm could switch to AA?+?P?+?ADT during an open-label extension. As in other studies where switching is allowed, statistical adjustments are needed to assess the real benefit of new drugs. PATIENTS AND METHODS:This was a post hoc analysis to estimate the true survival benefit of AA?+?P?+?ADT in patients with newly diagnosed mCSPC by applying statistical adjustments commonly used to adjust for treatment switching. RESULTS:Of 112 patients still receiving placebos?+?ADT at the first interim analysis, 72 switched to AA?+?P?+?ADT during the open-label extension. Final analysis was conducted after median follow-up of 51.8 months. Compared to the placebos?+?ADT arm, the risk of death in the AA?+?P?+?ADT arm was 34% lower [hazard ratio (HR)?=?0.663 (95% confidence interval 0.566-0.778)] by unadjusted intent-to-treat analysis, 37% lower [HR?=?0.629 (95% confidence interval 0.526-0.753)] by rank preserving structure failure time modeling, and 38% lower [HR?=?0.616 (95% confidence interval 0.524-0.724)] by inverse probability of censoring weights. CONCLUSIONS:Analyses adjusting for treatment switching using two different statistical approaches confirm the improved survival benefit of adding AA?+?P to ADT in patients with newly diagnosed mCSPC. TRIAL REGISTRATION:ClinicalTrials.gov identifier NCT01715285.
SUBMITTER: Feyerabend S
PROVIDER: S-EPMC6875513 | biostudies-literature | 2019 Dec
REPOSITORIES: biostudies-literature
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