Penpulimab, an anti-PD1 IgG1 antibody in the treatment of advanced or metastatic upper gastrointestinal cancers.

Background: The safety and anti-tumor activity of penpulimab in patients with advanced upper gastrointestinal (UGI) cancers were evaluated in this study.

Methods: Patients with advanced UGI cancers naive to immune checkpoint inhibitors were enrolled in two trials of penpulimab. In the Phase Ia/Ib trial in Australia, patients received penpulimab intravenous infusion of 1, 3 and 10 mg/kg every 2 weeks in dose-escalation phase and 200 mg every 2 weeks in dose-expansion phase. In the phase Ib/II trial conducted in China, patients received 200 mg penpulimab every 2 weeks. Primary endpoints were safety and tolerability for the phase Ia/Ib trial and the objective response rate for the phase Ib/II trial. The safety and efficacy of penpulimab in patients with UGI cancers in these two trials were evaluated.

Results: A total of 67 patients with UGI cancers from Australia and China were enrolled in these two trials and had received penpulimab with a median of 6 (1-64) doses. 44.8% of patients experienced at least one treatment-related adverse event (TRAE), and 7.5% of patients experienced a grade ≥3 TRAE. Among 60 patients evaluable for response, the confirmed objective response rates ranged between 11.1 and 26.3% across cohorts for pancreatic cancer, cholangiocarcinoma, gastric or Gastroesophageal junction carcinoma (Gastric/GEJ), and hepatocellular carcinoma. 11/13 (85.0%) responders had ongoing responses at data cutoff date.

Conclusions: Penpulimab monotherapy demonstrated an acceptable safety and encouraged anti-tumor activity in patients with advanced UGI cancers. Further exploration in a large cohort of patients is warranted.

Trial Registration: Phase Ia/Ib trial in Australia (NCT03352531) and phase Ib/II trial in China (NCT04172506).