IBI310 (anti-CTLA-4 antibody) monotherapy or in combination with sintilimab in advanced melanoma or urothelial carcinoma

IBI310 is a recombinant fully human IgG1 antibody against cytotoxic T-lymphocyte antigen 4 (CTLA-4). This study was conducted to evaluate IBI310 monotherapy or combination therapy with sintilimab in the patients with advanced melanoma or urothelial carcinoma (UC). Patients in phase Ia received IBI310 at 0.3/1/2/3 mg/kg intravenously (IV) every three weeks (Q3W) following the accelerated titration and 3 + 3 escalation design. Patients in phase Ib received IBI310 (1/2/3 mg/kg IV, Q3W) plus sintilimab (200 mg IV, Q3W) for 4 cycles, followed by sintilimab maintenance therapy. The phase Ib expansion of IBI310 plus sintilimab was performed in patients with advanced melanoma or UC. Overall, 53 patients were enrolled including 10 patients with melanoma in phase Ia, 34 with melanoma and 9 with UC in phase Ib. 94.3% (50/53) patients experienced at least one treatment-related adverse event (TRAE) with most being grade 1-2; 26.4% (14/53) patients experienced grade ≥3 TRAEs. In phase Ia, disease control rate (DCR) was 50.0% (95% CI: 18.7%-81.3%). In phase Ib, objective response rate (ORR) and DCR were 17.6% (95% CI: 6.8%-34.5%) and 44.1% (95% CI: 27.2%-62.1%) respectively for melanoma, and were 22.2% (95% CI: 2.8%-60.0%) and 66.7% (95% CI: 29.9%-92.5%) respectively for UC. IBI310 monotherapy or combination therapy with sintilimab was well-tolerated with favorable antitumor activity across patients with advanced melanoma and UC.