Ionis Pharmaceuticals announced the first patients have been dosed with ION541 (also known as BIIB105), an investigational antisense medicine being developed as a potential therapy to treat most forms of amyotrophic lateral sclerosis (ALS) regardless of family history. Almost all cases of ALS share the pathological hallmark of TDP-43 protein aggregation in motor neurons. ION541 targets ataxin-2 RNA (ATXN2), which has been shown to prevent or reverse TDP-43 toxicity in preclinical models of ALS.

ALS is a rare, progressive and fatal neurodegenerative disorder that affects approximately 55,000 people globally. About 90 percent of ALS cases occur in people who have no apparent family history of the disease. People with ALS experience muscle weakness, loss of movement, and difficulty breathing and swallowing, resulting in a severely declining quality of life and potentially death.

"As our third medicine designed to treat different forms of ALS to enter clinical trials, ION541 represents yet another example of the power of Ionis' antisense technology to potentially target root causes of devastating neurodegenerative diseases," said Frank Bennett, Ph.D., Ionis' chief scientific officer and franchise leader for neurological programs. "Initiation of this clinical trial for ION541 marks an important milestone in Ionis' ALS program and reaffirms our commitment to the ALS community."

Ionis received a payment of $10 million from Biogen for initiation of this Phase 1/2 clinical trial of ION541. Biogen is developing ION541 as part of a broad strategic collaboration with Ionis to advance novel antisense therapies for the treatment of neurological disorders.