Efficacy and Safety of HyQvia (Immunoglobulin 10% With Recombinant Hyaluronidase) in Multifocal Motor Neuropathy (MMN)

Inclusion Criteria: * Age at onset 18 - 65 years. * The presence of asymmetrical limb weakness at onset or motor involvement having a motor nerve distribution in at least two peripheral nerve distributions, predominant upper limb involvement, disabling weakness MRC grade 4 or less in at least one muscle. * Decreased or absent tendon reflexes in affected limbs. * Electrophysiological evidence of one site with definite motor conduction block or one site with probable conduction block according to previously defined criteria. * Response to SCIG according to criteria that were described in previous studies * On SCIG maintenance treatment for more than 3 months preceding the study. * Patients have given written informed consent, prior to the study, with the understanding that consent may be withdrawn at any time without prejudice. Exclusion Criteria: * Bulbar signs or symptoms. * Upper motor neuron signs (spasticity, hyperreflexia, extensor plantar response). * Sensory symptoms and signs with sensory deficits on examination (except for vibration sense) and abnormal results of sensory nerve conduction studies * Other neuropathies (e.g. diabetic, lead, porphyric or vasculitic neuropathy, chronic inflammatory demyelinating polyneuropathy, Lyme neuroborreliosis, post radiation neuropathy, hereditary neuropathy with liability to pressure palsies, Charcot-Marie-Tooth neuropathies, meningeal carcinomatosis). * Treatment with other immunosuppressive drugs (cyclophosphamide, azathioprin…