Guillain-Barré syndrome and checkpoint inhibitor therapy: insights from pharmacovigilance data

Background There are increasing reports of cases of Guillain-Barré syndrome (GBS), as an adverse event of an immune checkpoint inhibitor (ICI) but postmarket data on the incidence of this remains scarce. This study sought to conduct a comprehensive review of GBS events arising as a secondary outcome of ICI treatments in real-world patients, using the Food and Drug Administration Adverse Event Reporting System (FAERS). Methods Data covering the period from the third quarter of 2003 to the second quarter of 2023 were extracted from the FAERS database. GBS cases (associated with the usage of avelumab, atezolizumab, ipilimumab, nivolumab and pembrolizumab) were subjected to disproportionality analysis to detect potential signals. Results A total of 2208 reports of GBS were identified within the FAERS database, with 242 of these cases (10.9%) being associated with ICIs. All five drugs exhibited a disproportionality in the reporting of adverse events, with the highest observed for avelumab (reporting OR, ROR: 29.8), followed by atezolizumab (ROR: 17.0), ipilimumab (ROR: 16.0), pembrolizumab (ROR: 11.9) and nivolumab (ROR: 8.2). Conclusion These checkpoint inhibitors are associated with a statistically significant disproportionate number of reports of GBS as an adverse event, with avelumab being the ICI with the highest association. The present pharmacovigilance study serves as a valuable tool, offering a more comprehensive and nuanced perspective on GBS associated with ICIs. This study contributes to a deeper comprehension of this rare adverse drug effect.