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ALS development splits into precision and reach, with 28 programs between
Amyotrophic lateral sclerosis (ALS) drug development is trapped at two extremes, with all but 28 of 622 programs either targeting a specific mutation or pursuing broad neuroprotection. Sleuth’s January 2026 analysis groups the programs by estimated addressable patient population: 78 mutation-specific programs target SOD1, C9orf72 or FUS and mostly reach under 10% of patients, and 516 mechanism-agnostic neuroprotection programs mostly aim at 90% of patients or more. The 28 in between are genetically informed, but not restricted to a mutation.
The commercial case for broad ALS treatment is established. In December 2025, Shionogi agreed to pay about $2.5 billion for global rights to Tanabe Pharma’s edaravone (Radicava and Radicava ORS), and it completed the deal in April 2026. Sleuth reads the deal as validation that a pan-ALS drug can be a viable business, which moves the question for new assets to differentiation.
Mutation-specific programs have validation but small markets
Mutation-specific programs, including gene therapies and antisense oligonucleotides (ASOs), carry high scientific confidence because they act on a known genetic cause. Their ceiling is the population: the chart places almost all of the 78 below 10% of ALS patients. In Sleuth’s view, even perfect execution caps these assets at a single-digit share of the ALS market.
The approach can reach approval. Biogen and Ionis’s tofersen (Qalsody), an ASO, received FDA accelerated approval in April 2023 for SOD1-ALS, about 2% of ALS cases. After this analysis, on September 22, 2026, Ionis and Otsuka reported that ulefnersen met its primary endpoint, a combined measure of function and survival, in the Phase 3 FUSION trial in FUS-ALS, which accounts for about 0.6% of ALS cases. Approved CNS antisense drugs are all intrathecal treatments for single-gene diseases, as Sleuth’s RNA Intelligence Report shows.
Precision works in ALS, but each success serves a slice of patients measured in low single-digit percentages.
Broad neuroprotection has reach but little differentiation
The 516 mechanism-agnostic programs, such as antioxidants and anti-inflammatories, are not tied to a genetic subgroup, and in Sleuth’s January 2026 analysis most cluster at an estimated reach of 90% or more. In Sleuth’s reading, most cannot explain why they should work better than existing options such as edaravone.
Broad reach buys market size but not a reason to be chosen, so most of the ALS pipeline is competing on the same undifferentiated claim.
Genetically informed programs are the overlooked middle ground
The third group, 28 programs in January 2026, targets biology identified through ALS genetics that also goes wrong in most sporadic cases. Drugs aimed at TDP-43 protein aggregation are the clearest example: TDP-43 pathology is found in the large majority of ALS patients, not only in those with a known mutation. Estimated reach splits inside the group: 14 programs have an estimated reach of about 60% of patients or more, and 14 are below 25%.
Sleuth’s view is that the broad-reach programs in this group combine biological credibility, since they are not one more antioxidant, with reach across most of the patient population, and that they can be positioned as add-ons to edaravone rather than competitors. For BD teams, the implication is to stop forcing a choice between genetic precision and broad reach: the assets most likely to win have genetic validation that extends beyond rare mutations.
Program counts and groupings are from Sleuth’s January 2026 ALS analysis, and addressable populations are Sleuth estimates. The Shionogi deal, tofersen’s status and the ulefnersen Phase 3 result are current as of September 2026. This page is a dated snapshot.
Frequently asked questions about the ALS development landscape
How many ALS drugs are in development?
Sleuth sorted 622 ALS programs in its January 2026 analysis: 516 mechanism-agnostic neuroprotection programs, 78 mutation-specific programs targeting SOD1, C9orf72 or FUS, and 28 genetically informed programs that are not restricted to a mutation.
Are there approved ALS drugs that target a genetic cause?
Yes. Tofersen (Qalsody) received FDA accelerated approval in April 2023 for SOD1-ALS, about 2% of cases. As of September 2026, ulefnersen had positive Phase 3 results in FUS-ALS, about 0.6% of cases, reported that month, and was not yet approved.
What does “genetically informed but not mutation-restricted” mean?
It describes drugs whose target was found through ALS genetics but is also disrupted in most sporadic patients, such as TDP-43 aggregation. In Sleuth’s January 2026 analysis, 28 of 622 ALS programs fit this group.
