Biogen Inc. said Monday that it plans to seek US regulatory approval by the end of the year for an experimental drug to treat spinal muscular atrophy in infants.
The drug, called nusinersen, treats a rare genetic disease that currently has no approved treatments. It is part of Biogen’s push into new medicines for neurodegenerative diseases, including Alzheimer’s, to offset slowing sales of its industry-leading portfolio of multiple sclerosis drugs.
Encouraging new clinical data prompted Cambridge-based Biogen, the state’s largest biotech company, to exercise an option to exclusively develop and commercialize nusinersen. The compound originated in the labs of a Biogen partner, Ionis Pharmaceuticals Inc.
An interim analysis of the data, which analysts said was unexpected and ahead of schedule, showed that nusinersen met its primary goal of significantly improving motor functions in infants who took it in the late-stage trial, compared with those who didn’t.
Biogen and Ionis also said the experimental drug showed an acceptable safety profile in the patients.
“We’re all thrilled by the outcome,’’ Biogen chief executive George Scangos told stock analysts in a conference call. “Because when you see the kids and you see their parents, I think there’s nothing more emotional I’ve worked on in my career . . . We certainly appreciate the urgency of this.’’
Shares of Biogen climbed 4.1 percent to $301.83 Monday, while Ionis, based in Carlsbad, Calif., surged 30 percent to $38.01.
Biogen will pay $75 million to Ionis to take over the nusinersen program. Ionis will be eligible for up to $150 million in additional payments if the program meets regulatory milestones, and royalties on the sale of the drug if it wins regulatory approval.
In a note to investors Monday morning, Mark Schoenebaum, biopharma analyst for the research firm Evercore ISI in New York, called nusinersen a “major catalyst’’ for Biogen and estimated peak sales of $1.7 billion globally by 2025. “This is the first time Nusinersen has demonstrated clinical benefit in a controlled study . . . ’’ Schoenebaum wrote. “Nusinersen has demonstrated a remarkable lack of meaningful safety issues.’’
Spinal muscular atrophy, known as SMA, is a rare disease that causes loss of muscle control in infants and children. The leading genetic cause of death in infants, it affects about 12,500 people in the United States and 35,000 to 50,000 worldwide, according to Cure SMA, a 30-year-old patient advocacy group that has worked closely with the drug makers.
Biogen and Ionis have been under pressure from the families of children suffering from SMA to move more quickly with the program.
Alfred Sandrock, chief medical officer at Biogen, would not specify how soon the company will apply to the Food and Drug Administration for approval of nusinersen. But he said company officials worked all weekend on the application and have been in touch with European and Asian regulators.
“They are very interested in this program, and are encouraging us to file [applications] as rapidly as possible there as well,’’ Sandrock said.
Cure SMA president Kenneth Hobby said Biogen and Ionis have had to strike a balance between moving as quickly as they can to treat a disease for which there are no treatments and assuring they had the clinical data to support their regulatory applications. He said his group has been working to “make sure the patient perspective is factored in.’’
Biogen and Ionis said they were ending the nusinersen trial, which enrolled 122 patients around the world, but making the drug available to more infants at the clinical trial sites even before they file their FDA application.
Robert Weisman can be reached at robert.weisman@globe.com. Follow him on Twitter @GlobeRobW.
