Short-term follow-up of anti-MAG neuropathy patients given bendamustine plus rituximab combination therapy

Anti-myelin-associated glycoprotein (anti-MAG) IgM antibodies provoke demyelinating neuropathies, which can be particularly disabling. Conventionally, patients with anti-MAG neuropathies were treated with rituximab alone. This study aimed to evaluate the clinical and electrophysiological efficacy of bendamustine-rituximab (BR) combination therapy for anti-MAG neuropathy patients.

We retrospectively consulted the medical records of 11 patients whose diagnosis of anti-MAG neuropathy was retained and who were given BR combination therapy at university and community hospitals in northern France between 2017 and 2022. We collected clinical scores and electrophysiological data before BR therapy and at six to eleven months after treatment end (mean=8.40months).

After BR therapy, six of eleven patients (54%) showed an improvement in their overall neuropathy limitations scale (ONLS) score as did five of eleven (45%) in their peripheral neuropathy disability (PND) score, but these results did not reach statistical significance. For the six patients who had a more complete clinical revaluation based on the neuropathy impairment score (NIS), five improved (P=0.021). An improvement in the sensory NIS was observed in three of six patients (50%), while the motor NIS remained stable. Patients improving their PND score seemed to start from a higher baseline value. Five of eight (62%) patients with electrodiagnostic control data met Lunn and Nobile-Orazio's electrophysiological improvement criteria. The higher the baseline PND score, the less likely was improvement of electrodiagnostic parameters. No link between duration of disease progression before treatment and clinical response was found.

This multicenter cohort of anti-MAG patients given BR combination therapy is, to our knowledge, the largest published to date. Although BR therapy seems to improve the clinical and electrophysiological outcome of anti-MAG patients, precise evaluation scales are nevertheless needed to highlight improvement. Sensitive scales such as the NIS should be used routinely for monitoring anti-MAG patients. Prospective studies with a larger number of patients would be useful to confirm the efficacy of BR therapy in these patients.