SMA Drugs Jockey for Position in the Marketplace

The recent round of third-quarter earnings reports by spinal muscular atrophy (SMA) drugmakers provided a snapshot on how these medicines are performing around the world for the year to date and offered insights into how the companies are looking to expand their offerings to untreated patients next year.

The current top-selling SMA drug, Roche’s Evrysdi (risdiplam), approved by the FDA in 2020, “remains the global market leader for SMA with more than 16,000 patients treated,” Teresa Graham, Roche’s CEO, said during the company’s Oct. 23 earnings call, according to a transcript. The drug showed strong growth of 21% in the first nine months of 2024 to $1.45 billion. Roche attributed the increase to the medicine’s approval in more than 100 countries and it being the only noninvasive SMA drug.

The second-best-selling therapy, Biogen’s Spinraza (nusinersen), approved by the FDA in 2016, has faced challenges. Global revenue declined 13% to $1.15 billion for the first nine months of 2024 compared with the previous year. The company attributed the slide in part to a loss of a contract in Russia. Despite pricing and competitive pressures on Spinraza, Biogen expressed confidence in the drug’s growth potential.

“We are still finding new patients in this space, and that’s with three major biopharma companies putting money into this rare disease,” said Alisha Alaimo, Biogen’s president, head of North America, during the company’s Oct. 30 earnings call. “And a lot of our growth also comes from switchback — there’s a lot of patients [who] are returning back to Spinraza once they’ve switched away to a competitor, and they realize that maybe the efficacy isn’t there.”

The company expressed confidence in a higher-dose regimen currently being explored in its DEVOTE study, which recently demonstrated a clinically and statistically significant improvement in symptomatic infants. A separate cohort of patients ages 4 to 65 years also experienced improvements in motor function on the higher dose. Biogen plans to submit global regulatory filings for the higher dose by the end of 2024.

“These are exciting results as we seek to help patients currently on disease-modifying therapies,” Priya Singhal, M.D., Biogen’s head of development, said during the company’s Oct. 30 earnings call.

The higher-dose regimen, which consists of two 50-milligram loading doses followed by 28-milligram maintenance doses every four months, was generally well tolerated with a safety profile similar to that of the approved regimen.

“While we’ve seen great progress over the past decade in improving the lives of those with SMA, gaps remain and we can do more to address the full range of unmet needs and goals within our community,” said Kenneth Hobby, president of Cure SMA, in a Biogen news release. “The DEVOTE study’s findings are promising and show the potential for additional meaningful advancements that could further enhance motor function, which impacts daily living activities for all people living with SMA.”

Novartis’ one-time gene therapy, Zolgensma (onasemnogene abeparvovec), approved by the FDA in 2019, showed single-digit growth with sales of $952 million for the first nine months of 2024, a 3% increase from the previous year. The company is exploring a new application of the drug for older patients in its STEER study, with an administration into the cerebrospinal fluid, potentially enhancing the therapy’s effectiveness in targeting motor neurons in the spinal cord. If successful, this approach could address a patient population with few options.

Meanwhile, Roche is looking at adding a second drug, an anti-latent-myostatin antibody, to Evrysdi to boost its efficacy, said Azad Bonni, Roche’s senior vice president and global head of neuroscience and rare diseases, at an Oct. 31 investor event.

“What we’re currently doing is to determine [whether] we can get further improvement for patients with SMA by combining it with an agent that should lead to an increase in muscle size,” Bonni said at the event, according to a transcript. “We already have evidence preclinically that suggests this approach should work.” The company expects to share a readout of its phase two combo trial sometime next year.