New Drug May Slow Progression Of Als In Small Group Of Patients: Study

A new drug may slow progression of -- and even reverse --  symptoms of a rare form of amyotrophic lateral sclerosis, or ALS, a new study published Monday finds.

The drug, tofersen, targets a very specific mutation -- SOD1 -- which applies to only 2% of the ALS population.

Among this group, the drug has the potential to slow muscle degeneration by targeting SOD1 mRNA, genetic material that tells the body how to make proteins, and reduces the proteins being made.

The study, a phase III randomized controlled clinical trial, is an extension of the trial that earned Food and Drug Administration approval for tofersen in 2023.

Dr. Timothy Miller, the David Clayson professor of neurology at Washington University School of Medicine in St. Louis, told ABC News the results are encouraging after many studies and clinical trials over decades showed little to no effect at treating ALS.

"This is the first study where we see a really dramatic stabilization and slowing," he said. "I think we know from this study that [some forms of] ALS [are] treatable."

Patients show improvement in strength, function

ALS is a neurological disorder that affects nerve cells in the brain and spinal cord that control voluntary muscle movement and breathing.

As the nerve cells -- called motor neurons -- degenerate, they stop sending messages to the muscles. This causes the muscles to weaken and waste away, according to the National Institute of Neurological Disorders and Stroke (NINDS).

ALS patients eventually stop being able to control voluntary movement, including walking, talking and chewing, as well as breathing. NINDS said ALS is a progressive disease, meaning the symptoms worsen over time. There is currently no known cure.

The new drug tofersen, also known by the brand name Qalsody, is administered by injection into the spinal cord through lumbar puncture to treat ALS patients.

Results, published in the medical journal JAMA, found that more than 20% of patients who received tofersen at the start of the trial had improved strength and function at three years.

Miller said seeing not just stabilization, but also improvement, was "eye-catching" and "wowing."

"What's the likelihood, or how many people would you expect to have improvement or stabilization out of three years?" he said. "Three years is a long time for ALS, and the answer is zero ... and we just don't see that in the setting of ALS. This is basically unheard of in the setting of ALS."

All patients in the trial received the drug for two and a half years. However, one group of patients received the drug six months earlier and another group was on a placebo for the first six months.

Patients who received tofersen early had a 48% reduction in risk of death within six months compared to patients who received the placebo and started later.

While this drug only benefits a small number of ALS patients, Miller said the trial results are important because they show that targeting the underlying genetic cause can meaningfully slow disease progression and, in some cases, restore lost function, especially as the number of patients with ALS increases.

The Centers for Disease Control and Prevention (CDC) estimates that there are about 34,000 people in the U.S. living with ALS.

A CDC study earlier this year estimates the projected number of cases of ALS to rise in 2030 by more than 10% to more than 36,000 cases. The largest increase is expected to occur in the population aged 66 and older, with a 25% increase from about 16,000 cases in 2022 to about 20,500 cases in 2030.

"I am very hopeful for a cure for ALS," Miller said. "And I think that we're going to find drugs that substantially slow down ALS, make it a livable disease that will be ongoing treatment. I don't think anytime soon we're going to find something that makes the disease go away completely."

'It's like winning the lottery'

ALS patient Jessica Morris, a 37-year-old social worker and mother-of-three, said the drug has improved her quality of life considerably.

Morris developed early symptoms of ALS in March 2022, when her left knee began buckling due to muscle weakness, and she received a formal diagnosis later that year. By late 2022, she was dependent on a wheelchair for daily activities.

Morris carries the SOD1 gene and, although she was not part of the trial because she was diagnosed after it began, she was given permission to use the drug through FDA's expanded access pathway.

This allows seriously ill patients to receive investigational drugs outside clinical trials if there are no other available options.

"This drug provides hope, hope for a future that I never dreamed I would have," Morris told ABC News. "When you're first diagnosed, you almost have to grieve a life that you thought you were going to have." 

Morris lives in a two-story home and her muscle weakness had deteriorated to a point that she had to crawl up the stairs every night to go to bed. She began treatment in December 2022, and she noticed improvement just a few months later.

"One night in March, I went to walk up my stairs, and my body just naturally took the step," she said. "My husband was behind me and we both looked at each other and he was like, 'Did you just do that?' Between then and my next doctor's appointment, I started using my wheelchair a little bit less, and then a little bit less."

Morris said she no longer uses a wheelchair and is now able to perform daily activities with the use of a cane.

"It's like winning the lottery to have ALS and to have this opportunity, to actually have a medication that not only is supposed to slow the progression but, [for] me, got me out of a wheelchair. That's a big deal," she said.