Soliris Approved to Treat Myasthenia Gravis Patients Who Are AChR Antibody-positive in Japan

Alexion Pharmaceuticals announced that it has received approval to market Soliris (eculizumab) in Japan as a treatment for certain adults with generalized myasthenia gravis (gMG), according to a press release.

That decision, by that country’s Ministry of Health, Labor and Welfare, makes Soliris the first and only complement inhibitor approved in Japan to treat gMG in patients who are anti-acetylcholine receptor (AChR) antibody-positive and whose symptoms are difficult to control with high-dose intravenous immunoglobin therapy or plasmapheresis.

The agency based its decision on clinical data from the completed Phase 3 clinical trial (NCT01997229) known as the REGAIN study.

In REGAIN, and in its ongoing open-label extension study (NCT02301624), Soliris showed benefits for this specific set of patients who had previously failed to respond to or tolerate immunosuppressive treatment and continued to suffer from significant disease symptoms, including difficulties with breathing, seeing, walking or swallowing.

Ninety-four percent of patients who completed the 26-week REGAIN trial — or 117 out of 125 — opted to either continue or start treatment by participating in the 52-week extension study. Interim extension trial results, reported in September 2017, showed both groups experienced improvements in function, muscle strength and quality of life.

AChR antibodies inhibit acetylcholine, a neurotransmitter that sends messages between nerve cells and muscles, leading to a loss of muscle function. Soliris works by blocking a protein in the terminal part of what is called the “complement cascade,” a part of the immune system, that when activated in a way that is uncontrolled, can cause local inflammation and damage to the muscle membrane.

By selectively and effectively inhibiting the terminal complement cascade, Soliris targets the underlying cause of gMG.

Soliris was approved by the European Commission to treat refractory gMG in adults who are anti-AChR antibody-positive in August 2017,  and approved by the U.S. Food and Drug Administration for this same patient group in October 2017.

“Soliris represents an important treatment advance for patients in Japan with anti-AChR antibody-positive gMG who continue to suffer from significant unresolved disease symptoms despite existing treatment options,” said John Orloff, executive vice president and head of Research & Development at Alexion. “We are proud that these patients will be able to benefit from our deep understanding of complement biology, which allowed us to develop Soliris as treatment for this debilitating neuromuscular disorder.”

Between 5 and 10 percent of all myasthenia gravis patients are thought to be anti-AchR antibody-positive.