[Clinical analysis of combined immunotherapy in patients with malignant pleural mesothelioma]

Objective: To observe the present situation, efficacy and safety of immunotherapy in patients with malignant pleural mesothelioma (MPM). Methods: The data of 39 patients with MPM in two centers from 2016 to 2021 were collected and the efficacy and safety were evaluated. According to the application of immune checkpoint inhibitors (ICIs), these patients, whose median clinical follow-up amounting to 18.97 months, were divided into immunotherapy group (19 cases) and control group (20 cases). Kaplan-Meier method and Log-rank test were used for the survival analysis. Results: The objective response rate (ORR) and the disease control rate (DCR) in the immunotherapy group is 21.05% and 79.0% respectively, compared with 10.0% and 55.0% in the control group; and the difference was not statistically significant (P>0.05). The median overall survival (OS) in the immunotherapy group was significantly longer than that in the control group (14.53 months vs 7.07 months, P=0.015), but there was no significant difference in the median progression free survival (PFS) between two groups (4.80 months vs 2.03 months, P=0.062). Single factor survival analysis showed that the nature of pleural effusion, pathological subtype and the efficacy of immunotherapy were related to both PFS and OS of the patients with MPM (P<0.05). The incidence of adverse reactions in immunotherapy group was 89.5% (17 out of 19 cases), and the most common adverse event was hematological toxicity (9 cases), followed by nausea and vomiting (7 cases), fatigue (6 cases) and skin damage (6 cases). Five patients had immune checkpoint inhibitors (ICIs) related adverse reactions with grade 1-2. Conclusions: Patients with MPM have begun to receive immunotherapy in more than 2-line mainly combined chemotherapy in the real world, and the median treatment line is 2-line. Either combined with chemotherapy or anti-angiogenesis therapy, ICI inhibitors have significant efficacy, controllable adverse events and good clinical value.