Innovent Biologics, Inc. jointly announced with Eli Lilly and Company the final clinical outcome and biomarker analysis of the open label, phase Ib study (NCT04072679) of sintilimab plus bevacizumab biosimilar injection for advanced hepatocellular carcinoma at the 2022 ASCO Gastrointestinal Cancers Symposium (Abstract# 455). The study, which was conducted in China, evaluated the treatment of sintilimab plus bevacizumab biosimilar injection for patients with local advanced or metastatic HCC with or without previous systemic treatment or systemic treatment failure. The Phase Ib study included dose escalation and dose expansion stages.

In the dose escalation stage, patients were randomly assigned to receive sintilimab 200mg plus bevacizumab biosimilar 7.5 mg/kg (low-dose group) or 15 mg/kg (high-dose group). In the dose expansion stage safety and efficacy were assessed for each dose group. A total of fifty patients were enrolled in final analysis, with 29 patients administered bevacizumab biosimilar 7.5 mg/kg and 21 patients 15 mg/kg.

The safety profile was consistent with that observed in previously reported studies of sintilimab and bevacizumab biosimilar, without new or unexpected safety signals. The most common treatment-related adverse events (TRAE) were as hypertension (32%), proteinuria (26%) and fever (26%). The incidence of grade = 3 adverse events in the high-dose group was 28.6%, while 13.8% in the low-dose group.

The overall response rate (ORR) was 34% (17/50) and ORRs for the low-dose and high-dose groups were 31% and 38%, respectively. The disease control rate (DCR) was 78% (39/50). Median progression-free survival (PFS) was 10.5 months (95% CI, 8.4-12.7) and median overall survival (OS) was 20.2 months (95% CI, 16.1 -24.3).

Further biomarker analysis showed that patients with a high level of CD137 = 31.8 pg/mL have longer PFS (mPFS:14.2 vs. 4.1months, p=0.001) and OS (mOS: NR vs.15.6months, p=0.023). In addition, the Tumor immune Microenvironment(TiME)analysis demonstrated that the high density of M1 macrophages (CD68+, CD163-) in stroma was related to higher efficacy (p=0.033), longer PFS (p=0. 024) and OS (p =0.046).