Safety and efficacy of systemic chemotherapy plus PD-1 inhibitor in combination with intravenous or intraperitoneal bevacizumab in gastric cancer with peritoneal metastasis.

Background: For gastric cancer patients, peritoneal metastasis poses a life-threatening risk due to the high incidence of treatment failure and disease recurrence. Conducting additional research aimed at identifying more efficacious strategies is imperative for enhancing treatment outcomes. This study examined the efficacy and safety of systemic chemotherapy plus a PD-1 inhibitor combination with intravenous or intraperitoneal bevacizumab for gastric cancer with peritoneal metastasis.

Methods: We conducted the open label, two-arm pilot study involved receiving albumin-bound paclitaxel (260 mg/m, d1) plus S-1 (80 mg/m, d1-14) combined with sintilimab (200 mg, d1) and bevacizumab (7.5 mg/m, d1) (Arm A) intraperitoneally for moderate or large ascites or intravenously (Arm B) for non- or small ascites. The clinical trial was registered at the Chinese Clinical Trial Registry (ChiCTR2100048947 DATE: 2021-07-19).

Results: Ten gastric cancer patients with peritoneal metastasis were enrolled in two arms (four in Arm A and six in Arm B) from August 19th, 2021 to June 1st, 2022. Until the end of the follow-up date, the mPFS for Arm A was 5.70 m (95% CI: 1.29-10.11), while Arm B had a mPFS of 9.07 m (95% CI: 3.79-14.35). The mOS for Arm A and Arm B was 8.43 (95% CI: 6.70-10.17) and 11.23 months (95% CI: 2.90-19.56). At least one common Grade 3/4 AE occurred in 25% of Arm A participants and 16.7% of Arm B patients.

Conclusions: Albumin-bound paclitaxel plus S-1 with a PD-1 inhibitor and intraperitoneal or intravenous bevacizumab was well tolerated in gastric cancer patients with peritoneal metastasis.