Biogen and Ionis to Terminate Development of ALS Candidate

In a setback to the ALS community, Biogen Inc. (Nasdaq: BIIB) and Ionis Pharmaceuticals, Inc. (Nasdaq: IONS) have announced a decision to terminate development of BIIB105 (ION541). BIIB105, the companies’ candidate for the treatment of amyotrophic lateral sclerosis (ALS) was being evaluated in a Phase 1/2 study and failed to meet primary and secondary endpoints of reduction in levels of plasma neurofilament light chain (NfL), and clinical outcome measures of function, breathing, and strength.

Biogen’s shares dropped 2.50% to $229.43, and Ionis’ shares fell 5.89% to $36.90 following the news.

Stephanie Fradette, Pharm.D., Head of the Neuromuscular Development Unit at Biogen, thanked the trial’s participants, saying, “We are deeply grateful for the contributions of the study participants and remain committed to developing treatments that can meaningfully change the disease trajectory for people living with ALS.”

Similarly, Frank Bennett, Ph.D., Executive Vice President and Chief Scientific Officer of Ionis, said the company was “very appreciative of the people with ALS and investigators who participated in this study and were critical to advancing our scientific understanding of ALS.”

Ionis will continue to advance its Phase 3 ulefnersen program for the genetic form of ALS, known as FUS-ALS.

About Biogen
Founded in 1978, Biogen is a leading biotechnology company that pioneers innovative science to deliver new medicines to transform patients’ lives and to create value for shareholders and our communities. We apply deep understanding of human biology and leverage different modalities to advance first-in-class treatments or therapies that deliver superior outcomes. Our approach is to take bold risks, balanced with return on investment to deliver long-term growth.

We routinely post information that may be important to investors on our website at Follow us on social media – Facebook, LinkedIn, X, YouTube.

About Ionis Pharmaceuticals, Inc.

For three decades, Ionis has invented medicines that bring better futures to people with serious diseases. Ionis currently has five marketed medicines and a leading pipeline in neurology, cardiology, and other areas of high patient need. As the pioneer in RNA-targeted medicines, Ionis continues to drive innovation in RNA therapies in addition to advancing new approaches in gene editing. A deep understanding of disease biology and industry-leading technology propels our work, coupled with a passion and urgency to deliver life-changing advances for patients.

To learn more about Ionis, visit and follow us on X (Twitter) and LinkedIn.

Share This Article


About the Author

Biogen and Ionis to Terminate Development of ALS Candidate

Catie Corcoran

Biotech Editor