Lenalidomide in Anti-MAG Neuropathy: Phase 1b Study

Anti-myelin-associated glycoprotein (MAG) is a rare autoimmune disorder of the peripheral nerves that presents with weakness, gait imbalance, and loss of sensation. It almost always occurs in the setting of excess protein buildup in the body in the form of immunoglobulin monoclonal (IgM) gammopathy. Anti-MAG neuropathy currently has no established therapies. It is diagnosed through blood tests (anti-MAG and IgM), nerve conduction studies (which showed marked velocity slowing), and clinical exam findings.The efficacy of lenalidomide has been demonstrated in anti-MAG peripheral neuropathy with two separate dosing regimens: 25mg on days 1-21 of each 28 day cycle in conjunction with oral dexamethasone 20mg/day on days 1-4 of each cycle as well as at 5mg on days 1-21 of each cycle without oral dexamethasone. This phase 1 study aims to determine the maximum tolerated dose (MTD) of Lenalidomide in patients with anti-MAG neuropathy. We will explore preliminary efficacy and postulate that this drug is effective in this subset of patients, using preselected, specifically tailored outcome measures that encompass quality of life, neurologic function, serum protein levels, and focused measures of proprioception.