Biogen Inc. (NASDAQ:BIIB) unveiled results from a Phase 1b clinical study evaluating salanersen, an experimental antisense oligonucleotide therapy for spinal muscular atrophy (SMA), during the 2026 Muscular Dystrophy Association Clinical & Scientific Conference on Wednesday.
The trial involved 24 children aged between six months and 12 years who continued to show suboptimal clinical outcomes after receiving gene therapy. Each participant received at least two annual doses of salanersen—either 40 mg or 80 mg. According to a press release, all participants were followed for at least one year.
Results showed that patients treated with salanersen experienced a 75% drop in neurofilament light chain levels after six months, with the reduction sustained throughout the follow-up period. All 24 participants demonstrated improvements from baseline on at least one clinical endpoint. Twelve patients achieved at least one additional World Health Organization motor milestone, while every participant maintained the milestones they had already reached.
The treatment was generally well tolerated at both dosage levels. Among participants receiving the 40 mg dose, the most frequently reported adverse events were upper respiratory tract infections and vomiting. In the 80 mg group, the most common events were fever and upper respiratory infections. Most side effects were classified as mild to moderate.
Biogen also outlined the design of its upcoming Phase 3 clinical programme, which will evaluate an 80 mg dose of salanersen across three international studies. The STELLAR-1 study will focus on treatment-naïve infants younger than six weeks. STELLAR-2, a randomized, double-blind, sham-controlled trial, will examine salanersen administered six months after gene therapy in infants. The SOLAR study will evaluate the therapy in adolescents and adults aged 15 to 60 who are either treatment-naïve or previously treated with risdiplam.
Screening for STELLAR-1 has already begun. The SOLAR study is expected to launch in the second quarter of 2026, while STELLAR-2 is planned to start in the third quarter of the year.
Biogen obtained global development and commercialization rights for salanersen through a licensing agreement with Ionis Pharmaceuticals.
Biogen has also drawn attention from several analysts recently. Barclays initiated coverage with an Equalweight rating and a price target of $185. Goldman Sachs maintained a Buy rating and set a $231 price target, citing strong sales of the Alzheimer’s treatment Leqembi. BMO Capital Markets raised its target price to $196, pointing to potential growth for Biogen’s Spinraza therapy. Meanwhile, TD Cowen increased its price target to $215 after the company reported fourth-quarter results that exceeded revenue and earnings expectations.