Clinical trial data show NMOSD treatment reduces relapses
MIL62, approved in China, beats placebo in Phase 3 trial
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MIL62, a treatment approved in China to treat neuromyelitis optica spectrum disorder (NMOSD), was superior to a placebo at preventing relapses and controlling disease activity in people with the autoimmune disease.
That’s according to data from the Phase 3 portion of a China-based Phase 1b/3 clinical trial (NCT05314010), which also showed that two of 90 participants treated with MIL62 experienced a relapse after little over a year of treatment. Patients’ disability remained stable or reduced, and no new safety concerns were identified.
The findings, which supported MIL62’s approval, under the brand name Bejescin, in China earlier this year, suggest “that its benefit−risk profile was considered acceptable based on the available evidence,” the researchers wrote.
The results were published in Nature Medicine in the study, “Obinutuzumab β for aquaporin-4-positive neuromyelitis optica spectrum disorder: a phase 3 randomized controlled trial.”
NMOSD is characterized by inflammation and damage to the spinal cord and the optic nerves, which carry visual signals between the eyes and the brain. Most patients have self-reactive antibodies that target the AQP4 protein, and experience relapses (periods of new or worsening NMOSD symptoms) that can result in irreversible disability.
Treatment aims to reduce antibodies
MIL62, also known as obinutuzumab beta, is a third-generation, antibody-based therapy that binds to CD20, a protein found on the surface of B-cells, targeting them for destruction. B-cells are the immune cells responsible for producing antibodies, including those targeting AQP4.
The medication, administered directly into the bloodstream, aims to reduce the number of self-reactive antibodies, which may help reduce NMOSD relapses. Its design also suggests greater potency and efficacy compared with older anti-CD20 antibody-based therapies.
In Phase 1b of the trial, which involved 11 people with AQP4-related NMOSD, MIL62 demonstrated an acceptable safety profile and led to a rapid and persistent depletion of B-cells. It also kept most participants free of relapses for up to two years.
In Phase 3, 91 adults withAQP4-related NMOSD were randomly assigned to receive infusions of either MIL62 at a dose of 1,000 mg (45 patients) or a placebo (46 patients) in weeks 1 and 3, then in weeks 25 and 27.
The main goal of this part of the trial was to assess time to first relapse on or before 52 weeks. Data showed that significantly fewer people treated with MIL62 experienced a relapse compared with those on the placebo (4.4% vs. 45.7%), reflecting a 93.1% relative reduction in the risk of relapse with the therapy.
At the last visit, MIL62-treated patients showed a 0.37-point score reduction (improvement) on the Expanded Disability Status Scale (EDSS), a standard measure of disability, while participants given the placebo showed a 0.35-point score increase (worsening). This difference was statistically significant.
The therapy was also associated with a significant reduction in the cumulative number of active lesions on MRI and with B-cell depletion.
Adverse events deemed related to MIL62 were reported in 66.7% of patients, with infusion-related reactions the most common. Serious treatment-related side effects occurred in 6.7% the participants on MIL62, and included pneumonia (a lung infection), low levels of platelets (involved in blood clotting), and eyelid swelling.
At the last assessment, disability scores in the modified Rankin Scale were significantly reduced, and quality-of-life scores remained stable in participants treated with MIL62, while both measures worsened in those receiving a placebo.
Most participants who completed the trial’s one-year placebo-controlled portion chose to enter its open-label period (OLP), in which all participants are receiving MIL62. After the first month, the therapy was given about every six months.
From the first treatment administration through the May 2026 data cutoff, participants had been followed for a median of 65.57 weeks (a little over one year).
Among the 90 participants who received MIL62 at any point, two (2.2%) experienced relapses, both during the placebo-controlled portion. This corresponded “to a 97.9% reduction in relapse risk” compared with the placebo group in the first part, the researchers wrote.
Over about one year, disability also remained stable or decreased, with a mean EDSS reduction of 0.43 points, while 3.3% of participants experienced EDSS worsening.
“Overall, OLP follow-up confirmed sustained efficacy,” the researchers wrote. In addition, they said, long-term assessment of blood levels of anti-AQP4 antibodies “demonstrated a sustained and significant reduction after [MIL62] treatment.” B-cell depletion was also sustained.
The researchers noted that the very low relapse rate during the first year was notable because relapses can occur early after starting other B-cell-targeting therapies. They suggested that MIL62’s ability to rapidly deplete B-cells and its intensified first-year dosing schedule may have contributed to early disease control.
No new safety concerns emerged, and there was no evidence of increasing infection risk with continued treatment.
“These findings underscore [MIL62] as a clinically meaningful … anti-CD20 therapeutic option for relapse prevention in [AQP4-related] NMOSD while emphasizing the need for continued long-term follow-up,” the researchers wrote.
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