Enspryng for NMOSD Now Available in Taiwan, Chugai Announces

Enspryng has been approved by the Taiwan Food and Drug Administration for treating people 12 and older who have aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (NMOSD), Chugai Pharmaceutical announced.

The import drug license was given to Chugai Pharma Taiwan, a Chugai subsidiary, and represents the first approval for an NMOSD medicine in Taiwan.

“We are very pleased that Enspryng, created by Chugai, has been approved for the treatment of NMOSD, a disease with high unmet medical needs that has no approved treatments in Taiwan,” Osamu Okuda, Chugai’s president, said in a press release. 

NMOSD is an autoimmune disorder characterized by inflammatory damage to the optic nerves and spinal cord. Up to 80% of people with NMOSD carry elevated levels of aquaporin-4 antibodies (AQP4). Those antibodies target and damage a specific cell in the nervous system — astrocytes — by triggering a chain reaction in the immune system called the complement pathway. Activation of the complement pathway causes inflammation.

Enspryng (satralizumab-mwge) is a lab-made, humanized antibody that targets the receptors for the immune signaling protein interleukin-6 (IL-6), which plays a role in inflammation and is emerging as an important factor in NMOSD development. 

The Enspryng antibody was created by applying the company’s proprietary recycling antibody technology, which allows a single antibody molecule to bind to a target multiple times, prolonging the medicine’s effectiveness in the bloodstream. 

“Enspryng is the first approved product to apply our proprietary recycling antibody technology and the first NMOSD treatment targeting the IL-6 receptor,” said Okuda. “Chugai will cooperate with Chugai Pharma Taiwan so that Enspryng may be available to people with NMOSD in Taiwan as soon as possible.”

The therapy’s approval was based on data from two worldwide Phase 3 clinical studies, SAkuraSky Study (NCT02028884), evaluating Enspryng as an add-on therapy to patients’ usual immunosuppressants, and SAkuraStar Study (NCT02073279), to assess Enspryng as a monotherapy.

In the SakuraSky trial, 83 patients received either subcutaneous (under-the-skin) injections of 120 mg of Enspryng or a matching placebo. In those treated with Enspryng, only eight of 41 patients (20%) treated with Enspryng had a relapse compared to 18 of 42 (43%) of those receiving placebo. 

Of the 55 patients who were positive for AQP4-IgG antibodies, only three of 27 (11%) patients on Enspryng had a relapse, while 12 of 28 (43%) relapsed with placebo. The SAkuraSky trial is currently in its open-label phase, with completion estimated for March 2022.

The SAkuraStar trial, which included 95 patients, showed that 19 of 63 (30%) participants who received Enspryng had relapses, compared to 16 of the 32 (50%) of those who received placebo. The SAkuraStar trial also is in its open-label phase, estimated to conclude at the same time as SakuraSky.

Patients taking Enspryng may be at higher risk of serious infections and also may experience allergic reactions, elevated liver enzymes, and low neutrophils (a type of immune cell).

The most common side effects reported with Enspryng treatment were nose and throat irritation, headache, upper respiratory tract infection, stomach and joint pain, pain in the extremities, rash, and nausea.

Enspryng was approved for use in the U.S. for adults with AQP4-IgG positive NMOSD and is now approved in Taiwan, as well as Canada, Japan, Switzerland, the Dominican Republic, Guyana, Indonesia, Australia, and Curacao.

The medication has been designated an orphan drug in Europe, and the European Medicines Agency recently accepted an application for review.