Abstract 345P
Background
The China ARCHES trial previously found that, compared with androgen-deprivation therapy (ADT) + placebo (PBO), ADT + enzalutamide (ENZ) significantly reduced the risk for prostate-specific antigen progression and improved radiographic progression-free survival in patients (pts) with mHSPC in China. This exploratory analysis compared the effectiveness of ADT + ENZ vs ADT + PBO on time to deterioration of quality of life (QoL) and pain progression.
Methods
Pts with mHSPC were stratified by volume of disease (low/high) and prior docetaxel use (yes/no) then randomized 2:1 to ADT + ENZ or ADT + PBO. Time to QoL deterioration was defined as time from randomization to first occurrence of a ≥10-point decrease in the Functional Assessment of Cancer Therapy – Prostate score. Time to pain progression was defined as time from baseline to first occurrence of (1) a ≥30% increase in pain severity score on the Brief Pain Inventory – Short Form (BPI-SF), and (2) a ≥2-point increase in average BPI-SF score. Hazard ratios (HR) and KM curves were generated to evaluate differences between treatment effects.
Results
Of 180 pts, 120 received ADT + ENZ, and 60 ADT + PBO; 83 pts (69%) in ADT + ENZ vs 34 (57%) in ADT + PBO experienced deterioration in QoL. No significant difference in time to deterioration was observed between groups (HR: 1.2, 95% CI: 0.8—1.8). 74 pts (62%) in the ADT + ENZ vs 33 (55%) in the ADT + PBO experienced pain progression of ≥30%. Similarly, 54 pts (45%) in ADT + ENZ vs 23 pts (38%) in ADT + PBO experienced pain progression of ≥2 points. No significant difference between groups was observed for either definition of pain progression (HR [95% CI]: 0.9 [0.6—1.4]; 0.9 [0.5—1.4], respectively). Table: 345P
| Characteristics | ADT + ENZ n=120 | ADT + PBO n=60 |
| Deterioration of QoL, n (%) | 83 (69) | 34 (57) |
| Median time to deterioration of QoL, mo (95% CI) | 11.1 (8.3—13.8) | 16.5 (9.1—22.1) |
| Event-free rate at 12 mo, % | 48 | 58 |
| Cox HR (95% CI), p-value∗ | 1.2 (0.8—1.8), 0.4888 | |
| Pain progression (increase of ≥30% score), n (%) | 74 (62) | 33 (55) |
| Median time to progression, mo (95% CI) | 13.8 (8.3—16.6) | 8.3(5.52—NR) |
| Event-free rate at 12 mo, % | 52 | 40 |
| Cox HR (95% CI), p-value∗ | 0.9 (0.6–1.4), 0.5703 | |
| Pain progression (increase of ≥2 points), n (%) | 54 (45) | 23 (38) |
| Median time to progression, mo (95% CI) | 24.9 (19.5—NR) | 27.6 (12.3—NR) |
| Event-free rate at 12 mo, % | 66 | 66 |
| Cox HR (95% CI), p-value∗ | 0.9 (0.5–1.4), 0.5694 |
mo, months; NR, not reached *Log-rank p-value (nominal). Stratified by volume of disease & prior docetaxel use
Conclusions
There were no significant differences in QoL parameters among pts who received either ADT + ENZ or ADT + PBO, although QoL parameters appeared to be better in the ADT + PBO group.
Clinical trial identification
NCT04076059.
Editorial acknowledgement
Medical writing and editorial assistance were provided by Lindsay Wilson (MSc), Leena Patel (PhD), Chrysi Petraki (PhD), Jay Patel (PharmD), and Daria Renshaw (BA) from IQVIA.
Legal entity responsible for the study
Astellas Pharma Inc.
Funding
Astellas Pharma Inc.
Disclosure
H. Kadeerbai, Y. Liu: Financial Interests, Personal, Full or part-time Employment: Astellas. All other authors have declared no conflicts of interest.