Long term follow up of multifocal motor neuropathy with conduction block under treatment.

Natural history of 46 patients with multifocal motor neuropathy with conduction block

“…4,11,35 There have been anecdotal reports, small uncontrolled studies of series of patients, and two small double-blind trials that appear to demonstrate a benefit, at least in the short to intermediate term, for treatment with intravenous immunoglobulin (IVIg) and/or cyclophosphamide. 1,2,6,11,16,27,33,34 Despite these encouraging results, others have reported either no response to IVIg 15 or an initial response followed by unresponsiveness despite continued intensive IVIg therapy. 33 In addition to concerns over the effectiveness of therapy, the risks and costs of immunosuppressive therapy have not been sufficiently taken into account.…”

Inflammatory Demyelinating Neuropathies and Neuropathies Associated with Monoclonal Gammopathies: Treatment Update

“…In addition, a number of various uncontrolled studies also suggest a moderate beneficial effect of immunosuppressive treatments as adjunctive or second-line therapy to improve the response to and therefore reduce the need for frequent IVIg infusions. 17,39 It was recently reported that mycophenolate mofetil did not have a significant-sparing effect on IVIg. 49 Rituximab was reported to permit to delay by 1-week IVIg infusion in one patient increasingly less responsive to IVIg.…”

“…However, even with intensive IVIg therapy some patients had progression of neurologic deficits. 38 In addition, a proportion of patients does not respond to IVIg at the outset 39 or requires progressively more frequent doses to maintain remission. However, the response to increasing the IVIg dose or frequency tends to decline after several years.…”

Multifocal Motor Neuropathy: Update on Clinical Characteristics, Pathophysiological Concepts and Therapeutic Options

“…Although human IgM anti-GM1 antibodies can act on voltage-gated Ca 2+ channels in vitro, the significance of this interaction for the pathogenesis of MMN remains unclear [61]. The remarkable proportion of anti-GM1 antibody-negative patients (up to 50%) who, in comparison to anti-GM1-positive individuals, similarly respond to IVIg argues against an exclusively antibody-mediated disease mechanism [12,25,62,63]. Along these lines motor-nerve conduction in mice could be blocked by human serum samples devoid of anti-GM1 antibodies indicating that other soluble mediators are pathogenetically relevant in MMN [10,64].…”

“…Therefore, it is important to find an applicable maintenance regime with individualized IVIg doses (e.g. 0.4 g/kg IVIg once weekly or 1–2 g/kg IVIg in monthly intervals) in order to optimize the cost-to-benefit ratio [62,139]. Nevertheless the efficacy of IVIg decreases after several years of treatment in most of the patients, necessitating higher dosage or shortened infusion intervals to stabilize the symptoms [94,140].…”