Final analysis of ArtemisR, a European real-world retrospective study of apalutamide for the treatment of patients with metastatic hormone-sensitive prostate cancer

Abstract

BACKGROUND: We examined real-world outcomes of patients with metastatic hormone-sensitive prostate cancer (mHSPC) treated with apalutamide plus androgen deprivation therapy (ADT). The current study, reflecting real-life practice, included specific subpopulations not evaluated in the pivotal phase III TITAN study: patients diagnosed with novel imaging, patients with M1a disease only, and patients treated with concomitant radiotherapy. METHODS: ArtemisR is the first European multi-country observational study to retrospectively collect data from medical records of patients with mHSPC treated with apalutamide plus ADT in routine clinical practice. Response rates of patients with 50% and 90% decrease in PSA level (PSA50 and PSA90) compared with baseline and undetectable PSA (uPSA, < 0.2 ng/mL) were reported. Time to PSA response, time to metastatic castration-resistant prostate cancer (mCRPC), proportion of apalutamide discontinuation, and survival at 12 months were also examined using the Kaplan-Meier method. RESULTS: The analysis included 242 patients from Germany, France, Spain, and Austria; median age was 71 years. Median follow-up was 25.5 months from treatment initiation. Within 12 months of apalutamide initiation, 96% of patients achieved PSA50, 82% achieved PSA90, and 61% achieved uPSA. The median times to PSA50, PSA90, and uPSA were 1.08 months (95% confidence interval [CI]: 0.99-1.28), 1.94 months (95% CI: 1.54-2.27), and 3.48 months (95% CI: 2.92-5.68), respectively. At 12 months after treatment initiation, 94% of patients were alive, 91% had not progressed to mCRPC, and 81% remained on apalutamide plus ADT. Patients diagnosed with novel imaging, patients with M1a disease only, and patients treated with concomitant radiotherapy also showed deep and fast PSA responses (PSA90 and uPSA) with apalutamide plus ADT. Apalutamide-related adverse events (AEs) were reported in 90 patients (37%), and six patients (2.5%) discontinued apalutamide due to AEs. No new safety signals were detected. CONCLUSIONS: The ArtemisR European multi-centre study examined the efficacy and safety of apalutamide plus ADT for patients with mHSPC, further validating the deep and fast PSA response associated with this treatment regimen. These real-world outcomes were additionally observed in a more diverse patient population than that included in the pivotal TITAN study.