Roche Holding AG’s F. Hoffman-La Roche Ltd. gained FDA clearance for Enspryng (satralizumab-mwge) as the first and only subcutaneous treatment for adults living with anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD). The treatment will be available in the U.S. in two weeks.

A rare, lifelong and debilitating autoimmune disorder of the central nervous system, NMOSD is often misdiagnosed as multiple sclerosis and primarily damages the optic nerves and spinal cord, causing blindness, muscle weakness and paralysis.

Enspryng, which targets IL-6, was designed by Chugai, a member of the Roche group, using antibody recycling technology, which allows for longer duration of the antibody and dosing every four weeks by patients or their caregivers.

Results from two randomized, controlled phase III trials, called Sakurastar and Sakurasky, bolstered Enspryng’s approval. Strong results were sustained for 96 weeks, significantly reducing the risk of relapse compared with placebo as a monotherapy and when used along with baseline immunosuppressant therapy, commonly deployed to manage NMOSD symptoms associated with relapses.

Once low-profile, NMOSD has gained more attention lately with approvals last year of Soliris (eculizumab) from Boston-based Alexion Pharmaceuticals Inc., and more recently of Uplizna (inebilizumab-cdon) from Viela Bio Inc., of Gaithersburg, Md. Both are infused therapies. Soliris was first given the FDA nod in March 2007 for paroxysmal nocturnal hemoglobinuria.

The market will be sorting out the respective strengths and weaknesses of the trio in NMOSD. Unlike Enspryng and Soliris, Uplizna showed an impact on the disability endpoint in pivotal testing. It also turned up a strong safety profile, with 27% severe adverse event (SAE) rate vs. 6.3% for placebo and similar AE rates vs. placebo (71.8% vs. 73.2%). Soliris bears a black box warning and requirement for meningococcal vaccination. It’s given on an inpatient basis every other week. Uplizna is dosed, after induction, once every six months by way of a 90-minute infusion. “We are doubtful pricing will be a key differentiator or consideration for adoption given the unmet need,” Evercore ISI analyst Josh Schimmer said in a September report.