Inebilizumab (previously known as MEDI-551) is a humanized mAb that binds to and depletes CD19+ B cells including plasmablasts and plasma cells.
Inebilizumab is currently being tested in a phase 2 study for treating Neuromyelitis Optica Spectrum Disorder (NMOSD). NMOSD is a rare autoimmune disorder in which immune system cells and autoantibodies attack and damage the optic nerves and spinal cord. Clinically, the disease is manifested with attacks/relapses that result in neurological impairment such as blindness, paraplegia, sensory loss, bladder dysfunction, and peripheral pain. The disability from each attack is cumulative, making NMOSD a chronically debilitating and potentially life-threatening disease.
To date, there are no approved therapies for the treatment of NMOSD.
Autoantibodies against aquaporin-4 (and potentially other autoantibodies) in the spinal cord and optic nerve play a key role in the pathogenesis of the disease in most patients. Therefore, depletion of plasmablasts and plasma cells, the cells that produce these and other autoantibodies, can offer a targeted mechanism for the treatment of NMOSD.
Currently, the safety and efficacy of inebilizumab is being evaluated in the N-MOmentum study, the first randomized placebo-controlled trial in patients with NMOSD.
Inebilizumab has been studied in other indications. It has completed the Ph1 in MS and Ph1 Systemic Scleroderma and Ph2 in B cell malignancies.