Bempegaldesleukin plus nivolumab in first-line advanced/metastatic urothelial carcinoma: Results from a phase II single-arm study (PIVOT-10)

Background: In PIVOT-02, bempegaldesleukin (BEMPEG), a pegylated interleukin-2 cytokine prodrug, in combination with nivolumab (NIVO), a Programmed cell death protein 1 inhibitor, demonstrated the potential to provide additional benefits over immune checkpoint inhibitor monotherapy in patients with urothelial carcinoma, warranting further investigation. We evaluated BEMPEG plus NIVO in cisplatin-ineligible patients with previously untreated locally advanced or metastatic urothelial carcinoma. Methods: This open-label, multicenter, single-arm, phase II study enrolled patients with locally advanced/surgically unresectable or metastatic urothelial carcinoma and who were ineligible for cisplatin-based treatment. Patients received BEMPEG plus NIVO were administered intravenously every 3 weeks for ≤2 years or until progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by blinded independent central review (BICR) in patients with low programmed death ligand-1 (PD-L1) expression. Secondary endpoints included ORR and duration of response in the overall population. Progression-free survival (PFS) and overall survival (OS) were exploratory endpoints. Results: One hundred and eighty-eight patients were enrolled; 123 patients were PD-L1 low (combined positive score [CPS] <10; 65.4%), 59 were PD-L1 high (31.4%; CPS ≥10), and 6 had PD-L1 status unknown (3.2%). ORR per blinded independent central review in patients with PD-L1-low tumors was 17.9% (95% confidence interval [CI] 11.6–25.8) while in all treated patients was 19.7% (95% CI 14.3–26.1). Median PFS and OS in the overall population were 3.0 months and 12.6 months, respectively. BEMPEG plus NIVO combination was well tolerated, with a safety profile similar to previously reported trials; no new or unexpected safety signals were reported. Conclusions: BEMPEG plus NIVO did not meet the efficacy threshold for ORR in patients with previously untreated locally advanced or metastatic urothelial carcinoma and low PD-L1 expression.