HONG KONG – Tokyo-based Chugai Pharmaceutical Co. Ltd. has launched a subcutaneous injection of Enspryng (satralizumab) in Japan to prevent relapses of neuromyelitis optica spectrum disorder (NMOSD), including neuromyelitis optica (NMO). The product, listed on the National Health Insurance (NHI) reimbursement price list, is priced at ¥1,532,660 (US$14,428.3) per syringe.
The drug, which won FDA approval on Aug. 17 for the treatment of anti-aquaporin-4 (AQP4) antibody-positive NMOSD, is the first and only subcutaneous treatment available for adult patients living with the disease and was scheduled to be available in the U.S. two weeks after the approval.
Approval from Japan’s Ministry of Health, Labor and Welfare (MHLW) arrived on June 29, on the back of an application filed by Chugai on Nov. 8, 2019. Enspryng has also been approved in Canada and Switzerland, receiving orphan drug status in Europe after the EMA accepted the application for review on Oct. 30, 2019.
Two global phase III studies, together representing one of the largest clinical trial programs for NMOSD, helped to pave the way for the approvals. The Sakurastar study tested the drug as a monotherapy for NMOSD, with the results published in The Lancet Neurology on April 22. Meanwhile, the Sakurasky study tested the drug as add-on therapy to baseline immunosuppressant treatment for the same indication, and the results were published on Nov. 27, 2019 in The New England Journal of Medicine.
The drug is a pH-dependent binding humanized anti-IL-6 receptor monoclonal antibody. Developed to address NMOSD patients’ needs using Chugai’s recycling antibody technology, it works by inhibiting cytokine IL-6, a key driver in the disease. “Chugai has long engaged in research in interleukin-6 (IL-6) protein, which is known to play a key role in NMOSD’s pathology,” a spokesperson for Chugai told BioWorld.
Often misdiagnosed as multiple sclerosis, NMOSD, also known as Devic's disease, is an autoimmune disease affecting the central nervous system, with inflammatory lesions in the optic nerves and spinal cord causing permanent neurological disability. Symptoms include visual impairment, motor disability and pain. Patients are most likely to experience repeated attacks, which lead to accumulated neurological damage, disability and even death.
Aquaporin-4 antibodies (AQP4-IgG), pathogenic antibodies detected in around 70% to 80% of NMOSD patients, target and damage astrocytes, resulting in inflammatory demyelinating lesions of the optic nerve, spinal cord and brain.
Enspryng is not the only NMOSD treatment gaining attention. Boston-based Alexion Pharmaceuticals Inc. received FDA approval in July for Soliris (eculizumab) as a treatment for adult NMOSD patients who are anti-AQP4 antibody-positive. More recently, Viela Bio Inc. won FDA approval for Uplizna (inebilizumba), its humanized anti-CD19 monoclonal antibody to treat adults with NMOSD, in June.
Multiple projects underway
Chugai is also co-developing a digital solution for measuring pain levels in endometriosis patients with Boston-based Biofourmis Inc. The clinical-grade, wearable device resembles an Apple watch and is yet to be named. The companies hope to start phase I trials of the device soon.
Any positive results from the trials will be used to develop AMY-109, Chugai’s antibody treatment for endometriosis. The company has started phase I trials of the candidate in that indication, as well as an additional phase I trial for a solid tumor indication.
Chugai has also been active in its efforts to help address the COVID-19 pandemic, evaluating Actemra (tocilizumab) in hospitalized adults with severe COVID-19 associated pneumonia. However, the company said at the end of July that a phase III trial, Covacta, failed to meet its primary endpoint of improved clinical status. The study also failed to meet additional key secondary endpoints, including an improvement in patient mortality at week four. The company said that it would further analyze the study results to fully understand the data, and then submit the results for publication in a peer-reviewed journal.