Immune checkpoint inhibitor-related myotoxicity in lung cancer: a decade-long real-world pharmacovigilance analysis of the FAERS database.

Background: Immune checkpoint inhibitor therapy has revolutionized the treatment of several malignancies, with improved survival, yet the accompanying myotoxicity has often been underestimated. We aimed to comprehensively and comparatively analyze the risk of myotoxicity associated with various ICIs using the FDA Adverse Event Reporting System database. Methods: Data spanning from the first quarter of 2015 to the fourth quarter of 2024 were extracted from the U.S. Food and Drug Administration Adverse Event Reporting System database. Disproportionality analysis was conducted using the reporting odds ratios (RORs) and corresponding 95% confidence intervals (CI) to identify potential safety signals associated with ICI-related myotoxicity. Results: From 2015 to 2024, a total of 45,266 ICI-related myotoxicity reports were reported, of which 1,515 met the inclusion criteria, with a higher proportion of male patients (n = 904,59.7%). The median age was 69.4 years (interquartile range 49.9-77.6), and 46.2% of the patients were aged 65-85 years. A total of eight positive signals were identified, mainly myalgia [N = 366, reporting odds ratio = 1.25,95%confidence intervals (1.1-1.41), proportional reporting ratio = 1.25, χ2 = 12.55] and muscular weakness [N = 317, ROR = 1.53,95%CI (1.33-1.75), PRR = 1.53, χ2 = 37.75]. Among these events, polymyositis and rhabdomyolysis showed the highest proportions of fatal outcomes (42.86% and 38.83%, respectively). Among myositis-related reports, Triple M overlap syndrome was identified in 5.6% of cases, with fatal outcomes reported in 46.75% of these reports. In terms of onset time, 49.6% of the cases occurred within the first month of treatment (n = 303). The onset time of atezolizumab was the earliest (median 21 days), while durvalumab and Pembrolizumab showed longer or delayed risk windows (median 36 days and 34 days, respectively). And there were significant differences in the onset time of different ICI-related myotoxicity (P = 0.003). Conclusion: This FAERS-based pharmacovigilance study identified heterogeneous reporting signals and clinical patterns of ICI-associated myotoxicity. Most reported events occurred within the first 2 months of treatment, while myositis overlap syndromes, particularly the Triple M phenotype, were associated with higher proportions of fatal or life-threatening outcomes. These findings highlight the importance of early recognition and multidisciplinary monitoring of ICI-associated myotoxicity. Further clinical studies are warranted to validate these findings and clarify their underlying mechanisms.