Continuous Intrathecal Infusion of Nivolumab in Advanced Melanoma With Concomitant Leptomeningeal Disease: Efficacy, Safety, and Pharmacokinetics

BACKGROUND AND OBJECTIVES: Prognosis of melanoma with leptomeningeal disease (LMD) is poor (median overall survival of 5.1 months). Intrathecal (IT) nivolumab appears safe, although its efficacy remains uncertain. We investigated the feasibility, safety, and efficacy of continuous IT nivolumab. METHODS: This was a retrospective analysis of 11 melanoma patients with progressive LMD (MelBase; NCT02828202) treated as part of the patients' care with continuous IT nivolumab administered through spinal (n = 10) or ventricular catheter (n = 1). RESULTS: Patients (5 women, median age 52) with Eastern Cooperative Oncology Group ≤1 (except for 1) and stable extracranial disease (except for 4) were treated over a median duration of 1.5 months and followed for 2.5 months. Seven presented symptomatic LMD. Primary tumors were mostly cutaneous (n = 8) and BRAF-mutated (n = 10). All patients had progressed on systemic immunotherapy; 7 had received brain radiotherapy (whole brain radiotherapy n = 3; stereotactic radiosurgery n = 4). Concomitant therapies included corticosteroids >10 mg (n = 5), intravenous nivolumab (first 3 months of IT therapy, n = 1), and targeted therapies (n = 7). The median overall survival was 2.5 months, with 3 patients surviving for more than a year. Reversible treatment-related adverse events occurred in 5 patients: meningoencephalitis (grade 3, n = 1), intracranial hemorrhage (grade 1, n = 1), intracranial hypotension (grade 2, n = 2; grade 1, n = 1). Baseline levels of nivolumab in the cerebrospinal fluid (CSF) were <2 µg/mL, even among patients with plasma detection. CSF concentrations of nivolumab at steady state varied from 36 to 97 µg/mL, with clearances of 4.3-15.7 mL/h. Next-generation sequencing identified CSF genomic profiles correlating with clinical progression in 4 patients. CONCLUSION: These findings warrant further trials on IT nivolumab.