For the first time, a treatment for a genetic form of amyotrophic lateral sclerosis (ALS) has been shown to not only slow the disease but also lead to measurable improvement in strength and mobility for some patients. New research tracking patients over several years reveals that long term use of the drug tofersen can stabilize symptoms and even restore function in about one quarter of those treated, offering a rare bright spot in the fight against this devastating neurological condition.
ALS, often called Lou Gehrig’s disease, progressively destroys the nerve cells that control walking, talking, swallowing and breathing. The average life expectancy for patients with the SOD1 genetic subtype of ALS is just two to three years from symptom onset. The new study, which followed 108 participants from a phase 3 clinical trial and its open label extension, found that those taking tofersen over a period of three to five years experienced significantly slower disease progression than expected. Crucially, roughly 25 percent of patients in the early treatment group showed actual improvement in grip strength and respiratory function, a result researchers describe as unprecedented.
“Stopping disease progression and making improvements over three to five years is unheard of in this type of ALS,” said the study’s lead author, Dr. Timothy M. Miller. Tofersen is an antisense oligonucleotide, a type of drug that interferes with the production of the mutated SOD1 protein responsible for this rare form of the illness. The drug, approved by the FDA in 2023, is administered monthly via injection into the fluid surrounding the spinal cord. While the drug is not a cure and does not work for everyone, the findings show that patients who respond well can maintain independence and even regain abilities they had lost.
One patient, Rickey Malloy, a former plumber diagnosed with SOD1 ALS at age 41, has been on tofersen for two years. He reported far less muscle cramping and said his physical therapy team has added more exercises because walking and climbing stairs are getting easier. Remarkably, Malloy recently underwent a total knee replacement surgery that doctors had previously told him he did not qualify for because his ALS had been too severe. His wife, Jenny, called the medication “more than just treatment,” adding that it offers “hope, progress and a renewed belief that a cure is possible.”
The research also showed that tofersen prolonged survival. While SOD1 ALS patients typically live just over two years after symptoms begin, at least half of the trial participants were still alive nearly five years after the study started. The same antisense oligonucleotide technology used to develop tofersen is now being tested against other damaging proteins in other forms of ALS and related neurodegenerative diseases. Researchers are optimistic that the approach could eventually help a much larger group of patients.