US regulators have assigned AstraZeneca’s MEDI-551 Orphan Drug status as a treatment for patients with neuromyelitis optica (NMO) as well as neuromyelitis optica spectrum disorders (NMOSD).
NMO is a rare, life-threatening autoimmune disease of the central nervous system in which the body’s immune system attacks healthy cells, most commonly in the optic nerves and spinal cord, resulting in severe damage.
There is currently no cure or approved medicine for the condition, which affects about five in 100,000 people, causing symptoms such as severe muscle weakness and paralysis, loss of vision, respiratory failure, problems with bowel and bladder function and neuropathic pain.
MEDI-551 is a humanised, monoclonal antibody that binds with high affinity to CD19, a protein expressed on a broad range of B cells, including certain B cells called plasmablasts.
Research has shown that patients with NMO and NMOSD develop antibodies against a protein in their body called aquaporin-4, and these antibodies play a key role in NMO disease pathogenesis. MEDI-551 directly targets and depletes cells that produce these antibodies.
Developed by AZ’ biologics research and development arm MedImmune, the therapy is currently in Phase IIb clinical development for NMO and NMOSD, and is also being assessed in a Phase II trial in diffuse B-cell lymphoma.
“The orphan designation for MEDI-551 underscores the significant need for an effective medicine for NMO, a rare, devastating disease which causes increasing damage and disability with each attack,” said Bing Yao, head of the Respiratory, Inflammation and Autoimmunity Innovative Medicines unit at MedImmune.