European regulators have awarded AstraZeneca’s inebilizumab (formerly MEDI-551) Orphan status for the treatment of neuromyelitis optica spectrum disorder (NMOSD), opening the door to certain development and market exclusivity benefits.

NMOSD 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.

The condition, which affects around five in 100,000 people, can cause severe muscle weakness and paralysis, loss of vision, respiratory failure, problems with bowel and bladder function and neuropathic pain, and there is currently no cure or approved treatment for the disease.

Inebilizumab is a humanised, monoclonal antibody developed by MedImmune 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 NMOSD develop antibodies against a protein in their body called aquaporin-4, and these antibodies play a key role in disease pathogenesis. Inebilizumab directly targets and depletes cells that produce these antibodies.

The drug is currently in Phase IIb clinical development for the condition.

“The EMA’s orphan designation for inebilizumab underscores the significant unmet need for patients with NMOSD, who currently have no options and face increasing damage and disability with each attack. We look forward to continuing to develop this potential new medicine to help treat patients with this rare and devastating disease,” noted Bing Yao, senior vice president of R&D and head of the Respiratory, Inflammation and Autoimmunity Innovative Medicines unit at MedImmune.