Neurological outcomes in immune checkpoint inhibitor-related neurotoxicity

While the spectrum of neurological immune checkpoint inhibitor-related adverse events is expanding, patients’ outcomes are not well documented. This study aimed to assess outcomes of neurological immune-related adverse events and to identify prognostic factors. All patients experiencing grade ≥2 neurological immune-related adverse events identified at two clinical networks (French Reference Center for Paraneoplastic Neurological Syndromes, Lyon; and OncoNeuroTox, Paris) over five years were included. Modified Rankin scores were assessed at onset, 6, 12, 18 months, and last visit. A multi-state Markov model was used to estimate the transition rates between minor disability (mRS A total of 147 patients were included out of 205 patients with a suspicion of neurological immune-related adverse events. Median age was 65 years (range 20-87), and 87/147 patients (59.2%) were male. Neurological immune-related adverse events involved the peripheral nervous system in 87/147 patients (59.2%), the central nervous system in 51/147 (34.7%), and both systems in 9/147 (6.1%). Paraneoplastic-like syndromes were observed in 30/147 patients (20.4%). Cancers included lung cancers (36.1%), melanoma (30.6%), urological cancers (15.6%), and others (17.8%). Patients were treated with PD(L)1 inhibitors (70.1%), CTLA4 inhibitors (3.4%), or both (25.9%). Severe disability was reported in 108/144 patients (75.0%) at onset, and in 33/146 patients (22.6%) at last visit (median follow-up duration: 12 months, range 0.5-50); 48/147 (32.7%) patients died, from cancer progression (17/48, 35.4%), neurological toxicity (15/48, 31.2%), other causes (10/48, 20.8%), or unknown causes (6/48, 12.5%). The rate of transition from severe to minor disability independently increased with melanoma (compared to lung cancer, HR = 3.26, 95%CI [1.27; 8.41]) and myositis/neuromuscular junction disorders (HR = 8.26, 95%CI [2.90; 23.58]), and decreased with older age (HR = 0.68, 95%CI [0.47; 0.99]) and paraneoplastic-like syndromes (HR = 0.29, 95%CI [0.09; 0.98]). In patients with neurological immune-related adverse events, myositis/neuromuscular junction disorders and melanoma increase the transition rate from severe to minor disability, while older age and paraneoplastic-like syndromes result in poorer neurological outcomes; future studies are needed to optimize the management of such patients.