A Pilot Analysis of Capecitabine Plus PD-1 Antibody as Maintenance Therapy in Advanced or Metastatic Gastric Cancer and the Prognostic Factors

Oxaliplatin-based chemotherapy combined with PD-1 antibody has become the standard treatment for advanced or metastatic gastric cancer. However, the neurotoxicity of oxaliplatin limits its long-term use. A total of 84 patients who received oxaliplatin-based chemotherapy plus PD-1 antibody are enrolled in this study, among which 44 patients are maintained with capecitabine plus PD-1 antibody, whereas the other 40 patients are maintained with capecitabine monotherapy. The primary endpoint is progression-free survival (PFS) and the secondary endpoint is overall-survival (OS). Subgroup analysis is performed based on expression of PD-L1 and CXCL12. The median PFS is significantly longer in capecitabine plus PD-1 antibody group (n = 44) than that in capecitabine monotherapy (n = 40) group. The median OS is significantly longer in capecitabine plus PD-1 antibody group than that in capecitabine monotherapy group. Subgroup analysis showed that patients with high expression of PD-L1 or low level of CXCL12 benefited more significantly from capecitabine plus PD-1 antibody maintenance. Maintenance therapy with capecitabine plus PD-1 antibody significantly prolongs the PFS and OS in patients without disease progression after first-line treatment. Patients with high expression of PD-L1 or low expression of CXCL12 benefit more significantly from maintenance therapy.