Biogen recorded declining sales for Spinraza in each of the four quarters of 2025, but the Massachusetts drugmaker sees positive signs with the recent launch of its high-dose (HD) version of the spinal muscular atrophy (SMA) treatment in Japan.
With HD Spinraza already approved in Europe and Biogen facing an FDA decision on the new formulation on April 3, the company has high hopes for U.S. approval and similar launch trajectories.
“We’re certainly off to a better start than we expected. It’s not just in terms of adoption, it’s also switch backs,” CEO Chris Viehbacher said in a quarterly conference call Friday. “We certainly have seen much higher levels of efficacy in the study, which suggests that there’s an increased benefit from getting to a therapeutic level faster.”
After its FDA approval in 2016, Spinraza’s sales scaled up quickly, topping out at $2.1 billion in 2019. However, they’ve dropped to $1.55 billion last year, the company reported Friday. The decline throughout 2025 was especially precipitous, from $424 million in the first quarter to $356 million in the fourth, which fell well below analysts’ consensus projection from Visible Alpha of $385 million.
Competition from Roche’s SMA oral treatment Evrysdi, which was initially approved in 2020, has taken a toll. Last week the Swiss company reported Evrysdi sales at 1.76 billion Swiss francs ($2 billion). A year ago to the month, Roche scored an FDA nod for a tablet version of the treatment, gaining another convenience edge on infused Spinraza and Novartis’ gene therapy blockbuster Zolgensma, which also has seen a sales dip.
In discussions with physicians, Viehbacher said that the key question they face in treating SMA patients is “efficacy versus convenience.”
“If you ask them about efficacy, most of them believe it’s really Spinraza, but at some point, the convenience of the oral starts to attract patients,” Viehbacher said. “Here, we’re going to be dramatically increasing the level of efficacy, and I think the choice between oral and efficacy will be harder for some physicians and parents.”
As for the company’s performance overall in 2025, revenue reached $9.9 billion for a 2% year-over-year uptick. It was the first time since 2019 that Biogen saw an annual sales increase. The company generated revenue that year of $14.4 billion.
Biogen does not expect the growth to continue in 2026, however, projecting a mid-single-digit decline to a range of between $9.3 billion and $9.5 billion. The trend was reflected in fourth-quarter overall sales, which came in at $2.28 billion for a 7% year-over-year decline and a sequential slide from $2.54 billion.
When asked when to expect Biogen to return to growth, Viehbacher said much would depend on positive phase 3 results from two products which would be potentially launched in 2028. Until then, headwinds to growth include erosion in Europe for multiple sclerosis (MS) treatment Tecfidera and the recent introduction of biosimilar competition for another Biogen MS drug, Tysabri.
Viehbacher also is considering M&A.
“We continue to look for potential acquisition opportunities. These are companies with post-phase 3 results or are early stage in their commercialization, certainly no more than around the $5-to-$6-billion mark,” Viehbacher said. “There are certainly companies out there, but we haven’t found one that we can acquire for a price that we think makes sense for our shareholders, but we continue to look. We are looking every day in the marketplace.”