(UroToday.com) The European Society of Medical Oncology (ESMO) 2021 annual meeting’s prostate cancer session included a presentation by Dr. Byung Ha Chung discussing the efficacy and safety of apalutamide use in Asian patients with metastatic castration-sensitive prostate cancer (mCSPC). In TITAN study, the addition of apalutamide to androgen deprivation therapy (ADT) significantly improved radiographic progression-free survival (rPFS) and overall survival (OS) for mCSPC patients.1 Given that there may be regional differences in outcomes as part of global phase 3 trial, Dr. Chung and colleagues performed this TITAN Asian subgroup analysis with the results reported today at the ESMO 2021 congress.
This study was a posthoc analysis of subjects recruited from Japan, China, and South Korea. TITAN was a phase III randomized, double-blinded study where mCSPC patients were assigned (1:1) to receive either apalutamide (240mg daily) or placebo, in addition to ADT. The trial design for TITAN is as follows:
The co-primary endpoints were rPFS and OS. Exploratory endpoints included time to castration resistance and time to PSA progression.
This subgroup analysis included 111 patients on apalutamide and 110 patients on placebo group (median age 70 years). After the first analysis, 42.7% of patients in the placebo group crossed over to receive apalutamide. In the final analysis of rPFS, the apalutamide group had a statistically significant longer rPFS compared to placebo group (HR 0.511, 95% CI 0.305, 0.856; p=0.0094). In the final analysis of OS with a median follow-up duration of 42.5 months, there was a trend for improved OS in the apalutamide group compared to placebo (HR 0.685, 95% CI 0.416,1.126; p=0.1335) that was consistent with the overall population:
Kaplan-Meier OS curves:
Time to castration resistance (HR 0.309, 95% CI 0.206, 0.463; p<0.001) and time to PSA progression (HR 0.213, 95% CI 0.131, 0.346; p<0.001) were significantly improved in the apalutamide versus placebo group.
Kaplan-Meier time to castration resistance curves:
Frequency of treatment-emergent adverse events was 96.4% with apalutamide and 98.2% with placebo treatment. Skin rash incidence during apalutamide treatment (43.6%) was higher than for patients taking placebo (10.9%).
Dr. Chung concluded this presentation of the Asian subgroup analysis of the TITAN phase 3 trial with the following take home messages:
- In this subgroup analysis, after a median follow-up of 3.5 years, the efficacy and safety of apalutamide + ADT were consistent with the overall global cohort
- There were no new safety signals observed compared with the global population
Presented by: Byung Ha Chung, MD, PhD, Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Republic of South Korea
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2021 European Society for Medical Oncology (ESMO) Annual Congress 2021, Thursday, Sep 16, 2021 – Tuesday, Sep 21, 2021.
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