Soliris Keeps Improving Myasthenia Gravis Symptoms During Extension of Phase 3 Trial

Soliris (eculizumab) continued improving myasthenia gravis patients’ muscle strength and functioning in a 52-week extension of a 26-week Phase 3 clinical trial, researchers reported.

Alexion Pharmaceuticals said the extension study covered the same category of participant: patients with refractory generalized myasthenia gravis (gMG) who have anti-acetylcholine receptor (AchR) antibodies. The original Phase 3 trial was called REGAIN (NCT01997229), and the extension EMG-302 (NCT02301624).

Researchers presented the preliminary extension trial results at the annual meeting of the American Association of Neuromuscular & Electrodiagnostic Medicine in Phoenix, Sept. 13-16.

“There is an urgent need for a treatment for patients with refractory gMG who have attempted multiple therapies and continue to suffer from severe symptoms and complications,” Dr. James F. Howard, a University of North Carolina neurologist professor, said in a press release. He was a lead investigator in both the trial and extension study.

“These new results build on the findings of the REGAIN study,” Howard said. “It is encouraging to see the rapid and sustained benefits of Soliris treatment, with patients recovering functional ability to carry out activities of daily living, and quality of life.”

“We are grateful to the patients and investigators who continue to participate in this ongoing extension study that further substantiates the rapid and sustained benefits of complement inhibition for this debilitating, chronic and progressive neurological disorder,” said Dr. John Orloff, Alexion’s Executive Vice President and Head of Research and Development.

Ninety-four percent of the patients who completed the REGAIN trial — 117 out of 125 — joined the extension study. Fifty-six patients who received Soliris in the original trial continued to receive it in the extension. Sixty-one who received a placebo in the initial study were switched to Soliris in the extension.

Both groups experienced improvements in function, muscle strength and quality of life during the extension. Solaris’ safety profile in the extension was similar to that in the REGAIN study, researchers said.

The interim results of the extension trial included 49 patients in the Soliris/Soliris group and 56 in the placebo/Soliris group whom were assessed at 26 weeks. Twenty patients in each group completed week 52 assessments. The study is continuing. Alexion plans to finish it in January 2019.

REGAIN assessed Solaris’ safety and effectiveness over 26 weeks in 125 people with refractory gMG and antibodies against AChR.

Generalized myasthenia gravis is the term scientists give to the disease progressing to a more severe form. Hallmarks of gMG include muscle weakness extending to the head, neck, trunk, limbs and respiratory muscles.

Ten to 15 percent of patients with gMG are refractory, meaning that they fail to respond adequately or are unable to tolerate treatments. The result is that symptoms persist and complications develop.

These patients can face severe difficulties walking, talking, swallowing and breathing, and have double or blurred vision. The complications can require prolonged hospital stays and be life-threatening.

Soliris inhibits malfunctions of the complement system, part of the body’s immune response. When the system is working properly, it bolsters — or complements — antibodies’ ability to clear microbes from the body.

Malfunctions of the system can lead to a number of rare diseases, including refractory gMG. Soliris is the only complement-based therapy that the European Union has approved for treating refractory gMG with AchR antibodies.

Alexion is working on regulatory approval for Soliris in the United States and Japan. U.S. and EU regulators have given it Orphan Drug Designation for GM, and Japanese regulators have done the same for refractory gMG. Regulators grant the designation to promising treatments for rare diseases.