Immunotherapy in mesothelioma - systematic review and meta-analysis of immunotherapy impact on OS and its correlation with PFS and ORR.

Mesothelioma has a poor prognosis, with a 5-year overall survival (OS) rate less than 5%. Immunotherapy has been proven as a promising alternative to platinum-based therapies in first-line treatment. Our systematic literature search included 7 randomized clinical trials involving 2,549 patients to evaluate the impact of immunotherapy on OS across different lines of therapy, histologic subtypes, and ECOG performance status, and to assess the correlation between OS, progression-free survival (PFS), and objective response rate (ORR). Immunotherapy significantly improved OS (HR 0.78, P = 0.0005) with a similar benefit observed in first-line and second/later-line treatment (P = 0.25) as well as in all ECOG statuses (P = 0.32). A significantly greater benefit was observed in non-epithelioid compared to epithelioid mesothelioma (P = 0.002). Additionally, a strong correlation was shown only between OS and PFS (r = 0.86, P = 0.01). Our results emphasize the importance of immunotherapy in mesothelioma and further support PFS as a surrogate endpoint.