Phase 2 Study of the PD-1 Inhibitor Serplulimab plus the Bevacizumab Biosimilar HLX04 in Patients with Previously Treated Advanced Hepatocellular Carcinoma

Current treatments for patients with previously treated advanced hepatocellular carcinoma (HCC) provide modest survival benefits. We evaluated the safety and antitumor activity of serplulimab, an anti-PD-1 antibody, plus the bevacizumab biosimilar HLX04 in this patient population. Methods: In this open-label, multicenter, phase 2 study in China, patients with advanced HCC who failed prior systemic therapy received serplulimab 3 mg/kg plus HLX04 5 mg/kg (group A) or 10 mg/kg (group B) intravenously every 2 weeks. The primary endpoint was safety. Results: As of April 8, 2021, 20 and 21 patients were enrolled into groups A and B, and they had received a median of 7 and 11 treatment cycles, respectively. Grade ≥3 treatment-emergent adverse events were reported by 14 (70.0%) patients in group A and 12 (57.1%) in group B. Most immune-related adverse events were grade ≤3. The objective response rate was 30.0% (95% confidence interval [CI], 11.9–54.3) in group A and 14.3% (95% CI, 3.0–36.3) in group B. Median duration of response was not reached (95% CI, 3.3–not evaluable [NE]) in group A and was 9.0 months (95% CI, 7.9–NE) in group B. Median progression-free survival was 2.2 months (95% CI, 1.4–5.5) and 4.1 months (95% CI, 1.5–NE), and median overall survival was 11.6 months (95% CI, 6.4–NE) and 14.3 months (95% CI, 8.2–NE) in groups A and B, respectively. Conclusion: Serplulimab plus HLX04 showed a manageable safety profile and promising antitumor activity in patients with previously treated advanced HCC.