Chugai Files for Additional Indication of Enspryng as Japan’s Potential First Treatment for Prevention of Relapse in MOG Antibody-Associated Disease

TOKYO, Japan — Chugai Pharmaceutical Co., Ltd. (TOKYO: 4519) announced that it filed a regulatory application with the Ministry of Health, Labour and Welfare (MHLW) today for an additional indication of “prevention of relapse in MOG antibody-associated disease” for Enspryng^® [generic name: satralizumab (genetical recombination)], a pH-dependent binding humanized anti-IL-6 receptor monoclonal antibody created by Chugai.

“MOG antibody-associated disease (MOGAD) is a rare autoimmune disease in which repeated relapses may leave neurological symptoms, such as visual field and vision impairment, as well as paralysis, causing long-term impacts on patients’ lives. In a global Phase III study, Enspryng reduced the risk of relapse by 68% compared with placebo. We will work closely with the regulatory authority so that we can deliver Enspryng to patients with this disease, for which there are currently no approved treatments, as soon as possible,” said Chugai’s President and CEO, Dr. Osamu Okuda.

This filing is based on results from METEOROID, a global phase III clinical study in adults and adolescents (aged 12-17 years) with MOGAD. Development in Japan is conducted by Chugai, and Japanese patients have participated in this study.

[Footnotes]
Roche’s Announcement Regarding New Data of Enspryng for Myelin Oligodendrocyte Glycoprotein Antibody-associated Disease (MOGAD) (Apr. 22, 2026 news release)
https://www.chugai-pharm.co.jp/english/news/detail/20260422153000_1246.html

Chugai Receives Forerunner Designation for Enspryng in Myelin Oligodendrocyte Glycoprotein Antibody-associated Disease (MOGAD) and Autoimmune Encephalitis (AIE) (Mar. 24, 2023 news release)
https://www.chugai-pharm.co.jp/english/news/detail/20230324150001_976.html

About Enspryng
Enspryng, created by Chugai, is a pH-dependent binding humanized anti-IL-6 receptor monoclonal antibody, which was the first product developed by applying Chugai’s proprietary recycling antibody^® technology. Recycling antibody technology received “The Imperial Invention Prize,” the highest honor of the FY2026 National Commendation for Invention.¹ Enspryng is approved for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in approximately 90 countries, including Japan, the United States, and Europe. A global phase III clinical study is currently ongoing in autoimmune encephalitis (AIE). In addition, the U.S. Food and Drug Administration (FDA) has accepted the filing for thyroid eye disease (TED) and granted priority review.

About MOG antibody-associated disease (myelin oligodendrocyte glycoprotein antibody-associated disease, MOGAD)
MOGAD is an autoimmune disease involving demyelination by which a pathogenic autoantibody, an anti-MOG antibody, binds to MOG, which is expressed on the surface of the myelin sheath in the central nervous system. MOGAD causes inflammation of the optic nerves, spinal cord and brain, with symptoms such as visual impairment, loss of sensation, motor dysfunction and dysuria.^2,3 Currently, no approved therapies exist for the prevention of relapse in MOGAD, and in about 80% of adult patients, the disease is chronic and characterized by a relapsing course with currently used therapies. Therefore, high unmet medical needs remain.^2-8 The inflammatory cytokine IL-6 may play a role in the pathogenesis of MOGAD by promoting the production of autoantibodies⁹ and inducing inflammatory effects.¹⁰ The number of patients in Japan is estimated to be approximately 1,700.¹¹

Trademarks used or mentioned in this release are protected by law.

References

1. Chugai Receives “The Imperial Invention Prize,” the Highest Honor of the FY2026 National Commendation for Invention – Recycling Antibody Technology Recognized for its Contribution to Pharmaceutical Research – (May 26, 2026 news release) https://www.chugai-pharm.co.jp/english/news/detail/20260526113000_1253.html
2. Nakajima I. Brain and Nerve. 69(11):1331-1336, 2017
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4. Nakajima I. Neurotherapy. 36(3):220-224, 2019
5. Zamvil SS, et al. Neurol Neuroimmunol Neuroinflamm. 2(1):e62, 2015
6. Jarius S, et al. J Neuroinflammation. 2016 Sep 27;13(1):280.
7. Hyun JW, et al. J Neurol Neurosurg Psychiatry. 2017 Oct;88(10):811-817.
8. Salama S, et al. Mult Scler Relat Disord. 2019 May;30:231-235.
9. Chihara N, et al. Proc Natl Acad Sci USA 2011 Mar 1;108(9):3701-6.
10. Serada S, et al. Proc Natl Acad Sci USA. 2008;105(26):9041-6.
11. Nakamura M, et al. Mult Scler. 2023;29(4-5):530-9.