08:50 AM EDT, 05/16/2024 (MT Newswires) -- Biogen (BIIB) and Ionis Pharmaceuticals ( IONS ) said Thursday they would cease development of BIIB105 after a Phase 1/2 study showed the investigational ALS drug did not slow disease progression.

The companies said that while BIIB105 showed a reduction in ATXN2 protein levels, it did not decrease neurofilament or affect clinical outcome measures of function, breathing, and strength, indicating that it did not slow disease progression.

The study involved intrathecal administration of BIIB105 to ALS patients, with common adverse events including procedural pain, headache, and fall, the companies said. The placebo-controlled portion of the study showed higher adverse events in the BIIB105 cohort than in the placebo cohort, they added.

Shares of Biogen were down nearly 1% in recent Thursday premarket activity while Ionis stock was 1.8% lower.

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