Thursday, Ionis Pharmaceuticals Inc (NASDAQ:IONS) and Biogen Inc (NASDAQ:BIIB) decided to terminate the development of BIIB105 (ION541), an investigational antisense oligonucleotide (ASO) for amyotrophic lateral sclerosis (ALS) based on topline results from the Phase 1/2 ALSpire study.  BIIB105 was designed to reduce the expression of ataxin-2 (ATXN2) protein and demonstrated statistically significant cerebrospinal fluid (CSF) ATXN2 protein reductions in the study.  Related: Rare Disease Focused Ionis Pharmaceuticals Gears Up for FDA Submission After Donidalorsen Outperforms Placebo In Swollen Vessels Study. However, over the 6-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 ...