Tofersen, Phase 3 Valor Study, and Clinically Meaningful Impacts in SOD1-ALS

Neuromuscular Insights, developed in collaboration with the UCSF Health Department of Neurology, is a new expert-led series designed to bring clinicians closer to advances in neuromuscular care. The series features leading experts discussing emerging research, diagnostic strategies, and treatment considerations, with a focus on practical insights that can be applied in clinical neurology practice. In this debut episode, Catherine Lomen-Hoerth, MD, PhD, Richard K. Olney Distinguished Endowed Professor and Director of the ALS Center at UCSF, leads the discussion.

Lomen-Hoerth is joined by Timothy M. Miller, MD, PhD, ALS Center Co-Director, Miller Lab Director, and David Clayson Professor of Neurology at Washington University in St. Louis, to discuss the long-term clinical impact of tofersen in patients with SOD1-associated amyotrophic lateral sclerosis (ALS). Drawing on recently published data from the phase 3 VALOR study and its open-label extension, the conversation highlights how earlier initiation of therapy may influence disease trajectory. Over extended follow-up approaching 3.5 years, patients who started treatment earlier showed less decline across measures of function, respiratory capacity, muscle strength, and quality of life, along with signals suggesting improved survival compared with delayed treatment.

The discussion also provides context on the development of tofersen as an antisense oligonucleotide targeting SOD1 RNA and its delivery into the central nervous system. Dr. Miller reflects on the role of neurofilament light chain as a biomarker, including its use in the drug’s accelerated approval and its potential utility in both research and clinical settings. Longer-term findings are also explored, including stabilization or improvement in a subset of patients over multiple years, as well as the importance of early diagnosis, genetic testing, and timely treatment initiation. The episode concludes with perspectives on future therapeutic directions and the broader implications of RNA-targeted approaches in ALS.

Episode Breakdown

• 1:45 – Overview of ALS and SOD1-associated disease and who may benefit from therapy
• 3:15 –Development of tofersen and early biomarker findings with neurofilament
• 15:05 – Key results from VALOR and long-term extension data
• 18:50 – Clinical implications of early treatment and patient response patterns
• 26:00 – Role of neurofilament in diagnosis, monitoring, and trial design
• 31:50 –Future directions in ALS treatment and emerging therapies