JET-GBS - Japanese Eculizumab Trial for GBS

Gullain Barre Syndrome

Guillain-Barré syndrome (GBS) is an immune-mediated polyneuropathy that usually follows an antecedent infection and causes acute neuromuscular paralysis. GBS is currently classified into the two major subtypes: a classical demyelinating type and axonal variant type. Whereas in Europe and North America demyelinating GBS is the major subtype, in East Asia and Central and South America, axonal GBS is found in 30\ 65% of patients. Although the pathophysiology of GBS has not been fully understood, major advances have been made in understanding the pathophysiology particularly for the axonal form of GBS. It is now established that axonal GBS is caused by molecular mimicry of human gangliosides by the Campylobacter jejuni lipo-oligosaccharides. Autoantibodies bind to GM1 or GD1a at the nodes of Ranvier, activate complements, and disrupt sodium channel clusters and axo-glial junctions, resulting in the nerve conduction failure and muscle weakness. C. jejuni infection induces production of antibodies, which cross-react with gangliosides on the human nerve axolemma, and activate the complements, resulting in formation of membrane attack complex (MAC). The pathology leads to axonal degeneration. The standard treatments for GBS are plasma exchange and intravenous immunoglobulin and the disease progression reaches its nadir within 4 weeks. However, during the acute phase, 18-28 % of the patients require artificial ventilation and 4.1-6.3 % of the patients die of complications. Recovery takes several months or years, and 16.7-19.7 % of the patients still require aid to walk one year after onset. Because of such serious disability of GBS patients, an alternative novel therapy that can prevent death during acute phase or severe sequelae is needed. Eculizumab is a humanized monoclonal antibody of murine anti-human C5 antibody and specifically binds to the final activation complement component C5 and inhibits MAC formation by suppressing the cleavage reaction of C5 into C5a and C5b. The efficacy of eculizumab against GBS has been shown in a model of axonal GBS. At present, there are no animal models of demyelinating GBS. However, autopsy studies have shown that C3d and C5b-9 (MAC) are deposited on the Schwan cells, and therefore eculizumab can be effective also for demyelinating GBS. This clinical trial will be conducted to investigate the efficacy and safety of eculizumab for GBS to warrant future global clinical trials. Moreover, we also study the relationship between the efficacy and clinical subtypes of GBS, such as axonal or demyelinating form. Our trial will provide insights on whether the future global developmental plan should target the whole spectrum of GBS world-wide or focusing on Asia and South America.

Japan