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# Biogen/Ionis Scrap ALS Drug Development
- URL: https://www.fdaweb.com/biogen-ionis-scrap-als-drug-development/
- Published: 2024-05-16T12:00:00.000Z
- Updated: 2026-09-14T14:31:03.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5156999

Biogen and Ionis Pharmaceuticals say they are terminating the development of BIIB105 (ION541), an investigational antisense oligonucleotide for amyotrophic lateral sclerosis based on topline data from Phase 1/2 ALSpire study. The therapy was designed to reduce expression of ataxin-2 (ATXN2) protein and demonstrated statistically significant cerebrospinal fluid ATXN2 protein reductions in the study, according to the companies. “However, over the six-month placebo-controlled period, treatment with BIIB105 did not result in a reduction in levels of plasma neurofilament light chain (NfL), a marker of neurodegeneration and neuronal damage,” [they say](https://investors.biogen.com/news-releases/news-release-details/biogen-and-ionis-announce-topline-phase-12-study-results?ref=fdaweb.com). “Additionally, BIIB105 did not demonstrate an impact on clinical outcome measures of function, breathing, and strength.”