A Phase I Clinical Trial Evaluating the Safety and Dosing of Relugolix with Novel Hormonal Therapy for the Treatment of Advanced Prostate Cancer.

BACKGROUND: Androgen deprivation therapy (ADT), a cornerstone of prostate cancer treatment, is commonly co-prescribed as combination therapy. OBJECTIVE: To better understand the safety and tolerability profile of relugolix, an oral non-peptide gonadotropin-releasing hormone (GnRH) receptor antagonist, in combination with abiraterone acetate (abiraterone) and apalutamide, a phase I study was undertaken. PATIENTS AND METHODS: This is an ongoing, 52-week, open-label, parallel cohort study of relugolix in combination with abiraterone in men with metastatic castration-sensitive prostate cancer (mCSPC) or metastatic castration-resistant prostate cancer (mCRPC) [Part 1] and apalutamide in men with mCSPC or non-metastatic castration-resistant prostate cancer (nmCRPC) [Part 2]. Eligible patients treated with leuprolide acetate or degarelix with abiraterone or apalutamide prior to baseline, at which time they were transitioned to relugolix. Assessments included reporting of adverse events, clinical laboratory tests, vital sign measurements, electrocardiogram (ECG) parameters, and testosterone serum concentrations. In this interim report, patients completing ≥12 weeks were included. RESULTS: Overall, 15 men were enrolled in Part 1 and 10 in Part 2. Adverse events were mostly mild-to-moderate in intensity and were consistent with the known safety profiles of the individual medications. No transition (from prior ADT treatment)- or time-related trends in clinical laboratory tests, vital sign measurements, or ECG parameters were observed. Mean testosterone concentrations remained below castration levels. CONCLUSIONS: Combination therapy of relugolix and abiraterone or apalutamide was associated with a favorable safety and tolerability profile consistent with the known profiles of the individual medications. Castration levels of testosterone were maintained after transitioning to relugolix from other ADTs. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04666129.

Results of a Real-world Study of Enzalutamide and Abiraterone Acetate With Prednisone Tolerability (REAAcT).

BACKGROUND: The objective of this study was to evaluate differences in tolerability in patients with metastatic castration-resistant prostate cancer treated with enzalutamide (ENZA) or abiraterone acetate plus prednisone (AA+P). PATIENTS AND METHODS: 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 4 cognitive domains (Cogstate), patient-reported outcomes (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 [EORTC QLQ-30], Functional Assessment of Chronic Illness Therapy-Fatigue [FACIT-Fatigue], Functional Assessment of Cancer Therapy-Cognitive Function [FACT-Cog]), and patient/caregiver surveys were assessed at baseline and 2 months. Safety data were collected. RESULTS: 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% confidence interval, -6.61 to -1.39) for ENZA compared with AA+P, -0.01 (95% confidence interval, -2.40 to 2.38). Overall, more adverse events (AEs) and more AEs of fatigue were reported with ENZA versus 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 4 patients on ENZA versus 1 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. CONCLUSIONS: Although baseline values were similar, more fatigue and neurocognitive differences were observed with ENZA compared with AA+P.