Phase I study of envafolimab (KN035), a novel subcutaneous single-domain anti-PD-L1 monoclonal antibody, in Japanese patients with advanced solid tumors

Envafolimab is the first and only globally approved subcutaneously injectable PD-L1 antibody. This open-label, multicenter Phase 1 trial assessed the safety, tolerability, pharmacokinetic (PK) profile, and efficacy of envafolimab as a single agent in Japanese patients with advanced solid tumors. In the dose-escalation phase, 10 patients received subcutaneous (SC) envafolimab QW at 1.0 mg/kg, 2.5 mg/kg and 5.0 mg/kg. In the dose-expansion phase, 16 patients were treated at 2.5 or 5.0 mg/kg Q2W in part-1 and 9 patients received SC envafolimab 300 mg Q4W in part-2. No dose-limiting toxicities (DLTs) were reported. Envafolimab was well tolerated and no new safety signals were identified compared with other marketed products of the same class. Three patients reported Grade >= 3 envafolimab-related treatment-emergent adverse events (TEAE), including adrenal insufficiency, cerebral infarction, and immune-mediated enterocolitis. Envafolimab demonstrated dose-proportional increases in area under the time-concentration curve (AUC) and maximum serum concentration (C-max). The overall response rate (ORR) was 11.4% (n = 4) and disease control rate (DCR) was 34.3% (n = 12). Consistent with that observed in other envafolimab Phase 1 trials and approved PD-1/PD-L1 inhibitors, the safety profile of SC envafolimab in Japanese patients with advanced solid tumors was well tolerated with efficacy comparable to IV administered treatments. Pharmacokinetics data and preliminary anti-tumor response support dose regimens with longer dosing intervals (Q2W or Q4W). As such, envafolimab offers patients a more convenient treatment option than currently available intravenously administered PD-1/PD-L1 inhibitors. ClinicalTrials.gov identifier NCT03248843(August 14, 2017).

Automated summary

This study evaluated the safety, tolerability, pharmacokinetic profile, and efficacy of Envafolimab as a single agent in Japanese patients with advanced solid tumors. The results showed that Envafolimab was well tolerated and demonstrated comparable efficacy to intravenous treatments in Japanese patients. Pharmacokinetic data and preliminary anti-tumor response suggest longer dosing intervals as a more convenient treatment option.