Table 1.

Immune checkpoint inhibitor monotherapy evidence in mCRPC.

Trial Name/NCT	Phase	Patient Population	Treatment	Primary Endpoint	Results
CA184-095 (NCT01057810)	III	Chemotherapy-naïve patients with mCRPC without visceral metastases	Ipilimumab monotherapy	OS	28.7 months (95% CI, 24.5 to 32.5 months) in the ipilimumab arm versus 29.7 months (95% CI, 26.1 to 34.2 months) in the placebo arm (hazard ratio, 1.11; 95.87% CI, 0.88 to 1.39; p = 0.3667)
KEYNOTE-199 (NCT02787005)	II	Pretreated mCRPC patients in 3 cohorts (cohort 1 PD-L1 + disease, cohort 2 PD-L1 negative disease, cohort 3 bone predominant disease regardless of PD-L1 expression)	Pembrolizumab monotherapy	ORR	5% (95% CI, 2% to 11%) in cohort 1 and 3% (95% CI, <1% to 11%) in cohort 2
CA184-043 (NCT00861614)	III	Docetaxel-pretreated mCRPC patients	Ipilimumab vs. placebo after radiotherapy	OS	11.2 months (95% CI 9.5–12.7) for ipilimumab and 10.0 months (95% CI 8.3–11.0) for placebo (HR 0.85, 95% CI 0.71–1.00; p = 0.053)
CA184-095 (NCT01057810)	III	Asymptomatic or minimally symptomatic chemo-naïve patients with mCRPC	Ipilimumab vs. placebo	OS	28.7 months (95% CI, 24.5 to 32.5) for ipilimumab and 29.7 (95% CI, 26.1 to 34.2) in placebo (HR 1.11; 95% CI 0.88 to 1.39; p = 0.3667)
PCD4989g (NCT01375842)	Ib	mCRPC patients who have progressed on sipuleucel-T or enzalutamide	Atezolizumab monotherapy	Safety and tolerability of atezolizumab	Treatment- related adverse events in 60% of patients

Abbreviations: CI confidence interval; HR hazard ratio; mCRPC metastatic castration-resistant prostate cancer; ORR objective response rate; OS overall survival; PD-L1 programmed death-1 ligand 1.