(UroToday.com) The 2024 GU ASCO annual meeting featured a prostate cancer session and a presentation by Dr. Benjamin L. Maughan discussing survival outcomes of apalutamide as a starting treatment for patients with metastatic castration-sensitive prostate cancer (mCSPC) in the real-world. Over the last decade, androgen receptor signaling inhibitors (apalutamide, enzalutamide, abiraterone acetate + prednisone) in combination with ADT have emerged as more effective life-prolonging treatment options for mCSPC.1-2 At GU ASCO 2024, Dr. Maughan and colleagues examined the impact of androgen receptor signaling inhibitors starting therapy in mCSPC on long-term clinical outcomes in real-world clinical practice in the United States.
This retrospective, observational cohort study evaluated clinical outcomes in adult patients with mCSPC using the ConcertAI Real World Database 360 prostate cancer dataset. All patients with newly diagnosed mCSPC from January 1, 2018 to September 30, 2022 were enrolled and followed up until March 31, 2023. Among other outcomes, PSA50 and PSA90 (PSA response defined as a ≥50% and ≥90% decline from baseline, respectively) and undetectable PSA (PSA ≤0.2 ng/mL) were assessed using the Kaplan-Meier method. Relative risks of onset of castration resistance and death were estimated using multivariate Cox proportional hazard models adjusted for potential confounding factors (ie. age, comorbidities, BMI, baseline PSA).
There were 165 patients with mCSPC started on apalutamide + ADT, 643 started on enzalutamide + ADT, 1,064 on abiraterone acetate + prednisone + ADT, 293 on docetaxel + ADT, and 543 on ADT alone. The following table highlights the characteristics and outcomes in patients with mCSPC by starting regimen:
A higher proportion of patients initiating apalutamide achieved PSA50, PSA90, or undetectable PSA compared with other treatments. Castration resistance-free survival was significantly longer in patients first treated with an androgen receptor signaling inhibitors + ADT than those treated with docetaxel + ADT or ADT alone. Reduced risk of developing castration resistance was observed in patients starting with apalutamide + ADT compared with ADT alone (adjusted HR 0.36, 95% CI 0.19, 0.67). Overall survival was longer in patients started on androgen receptor signaling inhibitors compared to ADT alone. Patients starting with apalutamide + ADT were observed to have a lower risk of death compared with enzalutamide + ADT (adjusted HR 0.48, 95% CI 0.23, 0.99) or abiraterone acetate + prednisone + ADT (adjusted HR 0.43, 95% CI 0.21, 0.90).
Dr. Maughan concluded his presentation discussing survival outcomes of apalutamide as a starting treatment for patients with mCSPC in the real-world with the following take-home points:
- ADT alone continues to be used widely despite the availability of newer and more effective life prolonging therapies
- Use of apalutamide + ADT as starting treatment for mCSPC demonstrated significantly better clinical outcomes than other androgen receptor signaling inhibitors, docetaxel + ADT, or ADT alone in real-world clinical practice in the United States
Presented by: Benjamin L. Maughan, MD, PharmD, Huntsman Cancer Institute at the University of Utah, Salt Lake City, UT
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, San Francisco, CA, January 25th – January 27th, 2024
References:
- Chi KN, Agarwal N, Bjartell A, et al. Apalutamide for metastatic, castration-sensitive prostate cancer. N Engl J Med 2019 Jul 4;381(1):13-24.
- Chi KN, Chowdhury S, Bjartell A, et al. Apalutamide in patients with metastatic castration-sensitive prostate cancer: Final survival analysis of the randomized, double-blind, phase III TITAN study. J Clin Oncol. 2021 Jul 10;39(20):2294-2303.