To evaluate differences in tolerability in patients with mCRPC treated with enzalutamide (ENZA) or abiraterone acetate plus prednisone (AA+P).
This was a Phase IV, prospective, open-label, multicenter, real-world study. Patients were prescribed ENZA or AA+P at the treating physician’s discretion. Computerized tests of four cognitive domains (Cogstate), patient-reported outcomes (EORTC QLQ-30, FACIT-Fatigue, FACT-Cog), and patient/caregiver surveys were assessed at baseline and two months. Safety data were collected.
Of 100 treated patients, 92 were evaluable (46/arm). Baseline characteristics were similar with mild cognitive impairment observed in ∼20% of patients. The FACIT-Fatigue demonstrated a statistically significant worsening from baseline of -4.00 (95% CI: -6.61, -1.39) for ENZA compared to AA+P, -0.01 (95% CI: -2.40, 2.38). Overall, more adverse events (AEs) and more AEs of fatigue were reported with ENZA vs. AA+P (52% vs. 36% and 26% vs. 8% respectively). Grade 3/4 AEs were similar (4% vs. 6%). Unique neuropsychiatric AEs reported with ENZA included amnesia, cognitive disorders, memory impairment, and confusional state; those for AA+P included cerebrovascular accident, presyncope, and spinal cord compression. Clinically meaningful cognitive decline was seen in four ENZA patients vs. one patient on AA+P. However, the overall mean changes from baseline for the Cogstate tests, the EORTC QLQ-C30, and the FACT-Cog assessment were similar and showed no meaningful change. Caregiver survey responses noted more fatigue with ENZA and more moodiness with AA+P compared with patient responses.
While baseline values were similar, more fatigue and neurocognitive differences were observed with ENZA compared with AA+P.