Real-World Outcomes of Patients With Malignant Pleural Mesothelioma Receiving a Combination of Ipilimumab and Nivolumab as First- or Later-Line Treatment

Objectives: On the basis of the positive results of CheckMate-743, first-line (1L) treatment of malignant pleural mesothelioma (MPM) with the combination of ipilimumab and nivolumab (ipi-nivo) has become a standard-of-care. Furthermore, patients who received 1L platinum/pemetrexed chemotherapy are often considered for second or further-line (2L+) ipi-nivo on the basis of MAPS2 results. Here we report on real-world survival and safety outcomes of ipi-nivo for patients with MPM in Switzerland. Methods: Twelve cancer centers contributed data to this retrospective cohort. Baseline characteristics including age, sex, histology, programmed death-ligand 1 expression, Eastern Cooperative Oncology Group performance status (ECOG PS), and previous/subsequent therapies were collected. The efficacy and safety outcomes were assessed by local investigators. Results: Of the 109 patients with MPM treated with ipi-nivo between November 2017 and March 2023 (median follow-up of 16.6 months) 75% had epithelioid, 9% biphasic, and 16% sarcomatoid histology. The median age was 72 years; 91% were males, and 83% had an ECOG PS of 0 to 1. Ipilimumab in combination with nivolumab was given as 1L in 43% and as 2L+ treatment in 57% of patients. The objective response rate was 21% in 1L and 15% in 2L+. Median progression-free survival was 6.5 and 2.8 months, respectively. Median overall survival (OS) from the start of ipi-nivo was 12.6 months for 1L and 6.9 months for 2L+. No differences in OS were observed depending on age and programmed death-ligand 1 expression. Nevertheless, the median OS was significantly worse in patients with an ECOG PS of 2 or higher than those with an ECOG PS of 0 to 1 (2.4 versus 11.9 months, p < 0.001). Treatment-related adverse events (TRAEs) of any grade related to ipi-nivo treatment occurred in 65 patients (62%). The highest-grade TRAE was 1 to 2 in 58% of these patients and 3 or higher in 42% Treatment discontinuation due to a TRAE occurred in 22% of patients. Conclusion: In this real-world cohort of patients with MPM treated with ipi-nivo survival outcomes were inferior to those reported in the CheckMate-743 and MAPS2 trials, whereas safety outcomes were similar.