PURPOSE

To investigate the efficacy and safety of immune checkpoint inhibitors in the treatment of gastric cancer patients with different hepatitis B virus (HBV) infection statuses.

PATIENTS AND METHODS

The clinical data of 89 gastric cancer patients treated at our centre were retrospectively analysed. The patients were divided into chronic hepatitis B (CHB)-infected patients (13 patients), resolved hepatitis B (RHB)-infected patients (49 patients), and HBV-uninfected (HBV-) patients (27 patients) according to their HBV infection status. The efficacy and safety of antitumour treatment in patients in the three groups were analysed.

RESULTS

During anti-programmed death (ligand) 1 (PD-(L)1) therapy, no significant differences in the overall response rate (69.2% vs. 53.1% vs. 51.9%; P = 0.536) or disease control rate (92.3% vs. 79.6% vs. 81.5%; P = 0.567) were observed among the three groups. Progression-free survival benefited more from anti-PD-(L)1 antibody therapy in CHB patients than in HBV- patients (Not reached vs. 7 months; P = 0.024; hazard ratio (HR) = 0.38(95%CI 0.17-0.88)) and RHB patients (Not reached vs. 6 months; P = 0.001; HR = 0.34(95%CI 0.17-0.65)). Overall survival was also better in CHB patients than in HBV- patients (Not reached vs. 15 months; P = 0.014; HR = 0.31(95%CI 0.12-0.79)) and RHB patients (Not reached vs. 16 months; P = 0.005; HR = 0.32(95%CI 0.14-0.71)).

CONCLUSION

Anti-PD-(L)1 immunotherapy may be safe and effective in gastric cancer patients with HBV infection. CHB patients are more likely to have lasting benefits than are HBV- patients and RHB patients. This may be attributed to alterations in the immune microenvironment in patients, and future studies should further explore the relevant mechanisms involved. CHB patients may have a more inflamed immune microenvironment, leading to enhanced ICI efficacy.