A total of 50 patients with advanced HCC received sintilimab (200 mg) plus IBI305 (7.5 or 15 mg/kg), treated every 3 weeks in a phase 1b clinical study….A markedly longer PFS was observed in patients with high CD137 concentrations compared to those with low concentrations (median, 14.2 vs 4.1 months, P = 0.001).

In this two-part phase Ib study, patients with advanced or metastatic HCC were enrolled. Part 1 was dose escalation trial with sintilimab plus bevacizumab biosimilar (IBI305) 7.5 mg/kg (initial dose) or 15 mg/kg (escalated dose)...patients (CR+PR+SD≥12 weeks) had significantly higher level of serum CD137 than those with non-responder group (PD+SD≥12weeks) (median, 32.8 versus 19.8 pg/mL, P = 0.034). Patients with a high level of CD137 ≥ 31.8 pg/mL had longer PFS (mPFS:14.2 vs. 4.1months, P = 0.001) and OS (mOS: NR vs.15.6months, P = 0.023). The sintilimab plus IBI305 is well tolerated and effective, IBI305 of 7.5 mg/kg could be also optional to some patients. The serum CD137 and M1 macrophages are potential predicting biomarkers for the combination...