Reduced time to PSA90 with enzalutamide in Asian patients with mHSPC: An ARCHES post-hoc analysis
The ARCHES trials established that the use of ENZA plus ADT reduces the risk of death and improves rPFS in patients with mHSPC.1 The safety and efficacy of ENZA plus ADT in the East Asian population were demonstrated to be similar to that of the overall population through a post-hoc analysis of the Japanese subpopulation in the study.2
Dr Li and colleagues examined the AESIs and various efficacy outcomes in this post hoc analysis to investigate the impact of treatment duration on the safety and efficacy in the Asian population.3 The analysis included 147 patients in the Asian subgroup with 69 patients in the test group (ENZA plus ADT) and 78 in the control group (ADT plus placebo).3 The primary endpoint was the incidence rate of AESIs in 6-month intervals over 24 months (i.e., 0 to 6 months, 6 to 12 months, and 12 to 24 months).3 The key secondary endpoints were rPFS, OS, PSA90 and undetectable PSA level.3 It is worth noting that PSA90 is an important early response indicator of rPFS and OS in patients with mHSPC.4
Primary endpoint: AESIs
The incidence rate of AESIs decreased over the study period, with the highest incidence occurring within the first 6 months.3 The most common AESIs reported during the initial 6 months in the ENZA group were musculoskeletal events (15%), fatigue (13%), and hypertension (9%), after which the incidence declined rapidly to 6%, 0%, and 3%, respectively (Table 1). 3 ENZA plus ADT had the higher incidence of AESIs compared with ADT plus placebo. 3
Key secondary endpoints: rPFS, OS and PSA90
ENZA plus ADT reduced the risk of radiographic disease progression or death by 61% (HR, 0.39; 95% CI, 0.17–0.88; p=0.0061) compared with the control group (Figure 1).3 Patients receiving ENZA plus ADT did not reach the median rPFS, whereas those receiving placebo plus ADT had a median rPFS of 16.8 months.3
Throughout the evaluation period, patients receiving ENZA plus ADT showed superior rPFS compared with the control group: 92% versus 90% at 6 months, 87% versus 75% at 12 months, and 79% versus 47% at 18 months (Figure 1).3 Treatment with ENZA plus ADT also demonstrated improved rPFS (HR, 0.42; 95% CI, 0.19–0.95) regardless of age, Gleason score, disease volume, docetaxel therapy, disease localisation at baseline, and initial PSA level.3
Throughout the evaluation period, patients receiving ENZA plus ADT showed superior rPFS compared with the control group: 92% versus 90% at 6 months, 87% versus 75% at 12 months, and 79% versus 47% at 18 months (Figure 1).3 Treatment with ENZA plus ADT also demonstrated improved rPFS (HR, 0.42; 95% CI, 0.19–0.95) regardless of age, Gleason score, disease volume, docetaxel therapy, disease localisation at baseline, and initial PSA level.3
Neither treatment group reached the median OS by the end of the median follow-up of 45.9 months (Figure 2).3 However, ENZA plus ADT reduced the risk of disease progression or death by 36% (HR, 0.74; 95% CI, 0.35–1.55; p=0.2055) compared with placebo plus ADT.3
Interestingly, ENZA plus ADT significantly reduced the time to reach PSA90 (2.6 months versus not estimable for the control group) (Figure 3a).3 Additionally, 49.2% of patients receiving ENZA plus ADT had undetectable PSA levels by Week 13 (compared with 9.6% in the control group); the response was sustained throughout the study period (Figure 3b).3
Figure 3. The effect of ENZA plus ADT on PSA90 and PSA levels.3
Overall, the study result support the long term safety and efficacy of ENZA plus ADT in Asian patients with mHSPC.
ENZA plus ADT reduces the time to PSA90
– an important early response indicator of radiographic progression-free survival and overall survival – in patients with mHSPC3 3
– an important early response indicator of radiographic progression-free survival and overall survival – in patients with mHSPC3 3
Abbreviations: ADT, androgen-deprivation therapy; CI, confidence interval; ENZA, enzalutamide; HR, hazard ratio; mHSPC, metastatic hormone-sensitive prostate cancer; NE, not evaluable; OS, overall survival; PBO, placebo; PCa, prostate cancer; PSA, prostate-specific antigen; PSA90, median time to ≥90% reduction in PSA; rPFS, radiological progression-free survival.
References:
References:
- Armstrong AJ, et al. J Clin Oncol 2022;40:1616-1622.
- Iguchi T, et al. Int J Urol 2021;28:765-773.
- Li JR et al. Safety and efficacy of enzalutamide by treatment duration in the Asian subgroup from ARCHES: A post-hoc analysis. Presented at: Taiwan Urology Association (TUA) 2024 International Leaders’ Summit on Genitourinary Cancer; 9–10 March 2024; Kaohsiung, Taiwan.
- Matsubara N, et al. Eur Urol 2020;77:494-500.
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Tel: (852) 2377 9801 | Fax: (852) 2856 1440
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