Alexion's Soliris Misses Phase III Primary Efficacy Endpoint

Alexion Pharmaceuticals, Inc. (NASDAQ:ALXN) announced disappointing top-line data, as per which Soliris failed to meet the primary efficacy endpoint in a phase III study (REGAIN) in patients suffering from refractory generalized myasthenia gravis (gMG). We expect investors to react negatively to the news.

The randomized, double-blind, placebo-controlled, multi-center study was conducted to evaluate the safety and efficacy of Soliris in patients with refractory gMG. The primary efficacy endpoint of change from baseline in a patient-reported assessment – Myasthenia Gravis-Activities of Daily Living Profile total score at week 26 as measured by a worst-rank analysis – failed to achieve statistical significance.

However, the study did meet the first three secondary efficacy endpoints and a series of prospectively defined sensitivity analyses, which showed early and sustained substantial improvements in patients when treated with Soliris compared to placebo over a period of 26 weeks. Moreover, the safety profile of Soliris in this study was found to be consistent with the drug’s labels.

Alexion said that it continues to analyze the phase III study results and intends to meet with regulatory authorities to decide on the path forward. The company plans to present detailed results at the International Congress on Neuromuscular Diseases next month.

Per the company’s press release, refractory gMG is an ultra-rare segment of MG, which is a complement-mediated neuromuscular disease. Most gMG patients continue to suffer from this debilitating condition despite treatment with existing MG therapies.

Considering the lack of approved therapies for refractory gMG, there is a significantly unmet need for treatments addressing this disease. We note that Soliris has been granted orphan drug status in the U.S., EU, and Japan for the treatment of patients with MG.

Soliris, which is currently approved for the treatment of patients with paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome, is a key growth driver at Alexion. In 2015, the drug registered sales of $2.59 billion.

Alexion is also developing Soliris for several additional indications including neuromyelitis optica spectrum disorder and delayed kidney transplant graft function among others.

Alexion is a Zacks Rank #4 (Sell) stock. Some better-ranked stocks in the health care sector include ANI Pharmaceuticals, Inc. (NASDAQ:ANIP) , Retrophin, Inc. (NASDAQ:RTRX) and Bristol-Myers Squibb Company (NYSE:BMY) . All three stocks sport a Zacks Rank #1 (Strong Buy).