The US Food and Drug Administration (FDA) has recently granted accelerated approval for Biogen’s Qalsody (tofersen), a drug that targets a specific group of amyotrophic lateral sclerosis (ALS) patients who have a superoxide dismutase 1 (SOD1) gene mutation. This decision is considered a game changer for this rare subgroup of ALS patients and sets a precedent in the ALS space, says GlobalData, a leading data and analytics company.

GlobalData estimates that there are currently approximately 30,700 ALS patients in the US, with around 1% of them carrying a genetic mutation in the SOD1 gene.

According to GlobalData’s analysis of the ALS market, Qalsody was anticipated to gain approval as a disease modifying therapy for ALS this year, and is expected to be the third-highest selling drug in the US ALS market in 2029, generating sales of around $123 million.

In the Phase III clinical trial VALOR (NCT02623699), patients treated with Qalsody for 28 weeks experienced 55% reduction in plasma neurofilament light chain and 35% reduction of levels of SOD1 in the cerebrospinal fluid in comparison to 12% and 2% of patients in the placebo group. Patients enrolled in interim analysis of Qalsody’s OLE trial (NCT03070119) conducted at 52-week, experienced similar reductions as seen in participants treated with Qalsody in VALOR.

Early initiation of treatment with Qalsody also led to a reduction in decline on measures of clinical function in comparison to placebo/delayed start of the Qalsody treatment, although these results weren’t statistically significant. The most side effects patients on Qalsody experienced were of the moderate character, such as procedural pain, headache or pain in the arms or legs.

Barbora Salcman, Neurology Analyst at GlobalData, comments: “Overall, the results from Phase III clinical trial VALOR (NCT02623699) and its interim analysis of OLE trial (NCT03070119) are great news for ALS patients with a SOD1 mutation, especially as survival from onset for such patients is around 28 months in comparison to 35 months for patients with sporadic ALS (approximately 29,277 people in the US). In addition, Biogen is running another Phase III clinical trial, ATLAS (NCT04856982), to investigate if Qalsody can slow disease progression.”

Key opinion leaders (KOLs) interviewed by GlobalData consider Qalsody to be a game changer in the treatment of ALS. Although the drug will only help around 1% of patients from the whole ALS patient population in the US, KOLs are excited about the drug’s efficacy and its mechanism of action.

Salcman concludes: “The positive clinical trial results and a strong interest in the drug expressed by the interviewed KOLs show that Qalsody has a chance to become one of the leading drugs in the ALS market. While the drug targets a very small number of patients, it is seen as a revolutionary treatment for otherwise a devastating disease with fatal prognosis, which up until today has had no effective or curative treatment. The accelerated approval of Qalsody sets a precedent for personalized treatment in the ALS space and will hopefully inspire companies to pursue the development of agents for other ALS subtypes.”

Note: Although Biogen has not yet provided in the public domain information on its asset’s price, the company has indicated that the price range for Qalsody will be in a range comparable to other agents* that were recently launched for the treatment of ALS.

*Amylyx Pharmaceuticals’ Relyvrio, which was approved in September 2022 for the treatment of ALS, is currently priced at $158,000 per year.