PrECOG PrE0807: A Phase 1b Feasibility Trial of Neoadjuvant Nivolumab Without and with Lirilumab in Patients with Muscle-invasive Bladder Cancer Ineligible for or Refusing Cisplatin-based Neoadjuvant Chemotherapy.

BACKGROUND AND OBJECTIVE: Neoadjuvant cisplatin-based chemotherapy prior to radical cystectomy (RC) improves overall survival (OS) in muscle-invasive bladder cancer (MIBC). However, many patients are cisplatin ineligible; therefore, new treatment options are needed. Nivolumab without/with lirilumab prior to RC was investigated in cisplatin-ineligible patients in this phase 1b trial (NCT03532451) to determine its safety/feasibility.

METHODS: Patients with localized MIBC received two doses of nivolumab (480 mg) alone (cohort 1) or with lirilumab (240 mg; cohort 2) prior to RC. Cohorts were enrolled sequentially. The key eligibility criteria were cT2-4aN0-1M0 stage and cisplatin ineligibility/refusal. The primary endpoint was the rate of grade (G) ≥3 treatment-related adverse events (TRAEs) as per Common Terminology Criteria for Adverse Events version 5.0. The key secondary endpoints included the proportion of patients who underwent RC >6 wk after the last dose, CD8+ T-cell density change between pretreatment transurethral resection of bladder tumor (TURBT) and post-treatment RC, ypT0N0, <ypT2N0 rates, 2-yr recurrence-free survival (RFS), and OS.

KEY FINDINGS AND LIMITATIONS: Among 43 patients enrolled (n = 13, cohort 1; n = 30, cohort 2), 13 and 29 completed intended neoadjuvant therapy, respectively, in cohorts 1 and 2, and 41 underwent RC. The median time from the last dose to RC was 4 wk. The G3 TRAEs occurred in 0% (90% confidence interval [CI] 0-21%) of patients in cohort 1 and 7% (90% CI 1-20%) in cohort 2; all these TRAEs resolved and no G4/5 TRAEs occurred. No patient had delayed RC for >6 wk. In cohorts 1 and 2, ypT0N0 rates for patients with MIBC and RC were 17% and 21%, <ypT2N0 rates were 25% and 32%, 2-yr RFS rates were 73% and 71%, and 2-yr OS rates were 82% and 89%, respectively. CD8+ T-cell density increased significantly from TURBT to RC in cohort 2.

CONCLUSIONS AND CLINICAL IMPLICATIONS: Neoadjuvant nivolumab-based immunotherapy was safe, feasible, and well tolerated in cisplatin-ineligible patients with MIBC. Although ypT0N0 rates were lower than expected, 2-yr survival rates seem to be comparable with those of other neoadjuvant immunotherapy trials. Nivolumab is being evaluated in the CA-017-078 trial (NCT03661320).

PATIENT SUMMARY: For patients with muscle-invasive bladder cancer unable to receive cisplatin-based chemotherapy, treatment with nivolumab without and with lirilumab prior to radical cystectomy was safe, feasible, and well tolerated. Nivolumab-based immunotherapy showed lower pathologic response rates than but similar survival rates to other neoadjuvant immunotherapy trials.