Reintroduction of immune-checkpoint inhibitors after immune-related meningitis: a case series of melanoma patients.

Immune-checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated antigen-4 and programmed cell death ligand-1) are associated with several immune-related neurological disorders. Cases of meningitis related to ICIs are poorly described in literature and probably underestimated. Several guidelines are available for the acute management of these adverse events, but the safety of resuming ICIs in these patients remains unclear. We conducted a retrospective case series of immune-related meningitis associated with ICIs that occurred between October 1 2015 and October 31 2019 in two centers: Saint-Louis and Cochin hospitals, Paris, France. Diagnosis was defined by a (1) high count of lymphocytes (>8 cells/mm3) and/or high level of proteins (>0.45 g/L) without bacteria/virus or tumor cells detection, in cerebrospinal fluid and (2) normal brain and spine imaging. Patients were followed-up for at least 6 months from the meningitis onset. Seven cases of immune-related meningitis are here reported. Median delay of meningitis occurrence after ICIs onset was 9 days. Steroid treatment was introduced in four patients at a dose of 1 mg/kg (prednisone), allowing a complete recovery within 2 weeks. The other three patients spontaneously improved within 3 weeks. Given the favorable outcome, ICIs were reintroduced in all patients. The rechallenge was well tolerated and no patients experienced meningitis recurrence. In conclusion, in our series, the clinical course was favorable and steroids were not always required. Resuming ICIs in these patients appeared safe and can thus be considered in case of isolated meningitis. However, a careful analysis of the risk/benefit ratio should be done on a case-by-case basis.