The U.S. Food and Drug Administration approved a new drug Tuesday to treat a rare form of amyotrophic lateral sclerosis, or ALS.
The drug Qalsody (tofersen) is expected to help people with a very specific mutation, SOD1, which applies to only 2% of the ALS population.
In a statement, the FDA said it estimates “there are fewer than 500 patients with SOD1-ALS in the United States.”
Among those who qualify, the drug has the potential to slow muscle degeneration by targeting SOD1 mRNA, or mRNA, genetic material that tells the body how to make proteins to reduce the protein being made.
Studies showed that the drug reduced plasma neurofilament light (NfL), a blood-based biomarker of axonal (nerve) injury and neurodegeneration, according to the FDA.
“Patients receiving Qalsody had nominally significant reductions in plasma NfL concentration at Week 28 compared to the placebo arm,” the FDA said in a statement.
The drug is given via a lumbar puncture — or a spinal injection — with three doses in 14-day intervals, followed by monthly dosing.
Researchers determined Qalsody to be safe with the most common side effects being pain, fatigue, joint and muscle pain and increased white blood cells in cerebrospinal fluid.
The drug was given conditional approval by the FDA under the fast track designation. Biogen, which makes the drug, will still need to complete additional and larger studies on its effectiveness.
It comes after the FDA approved another drug from Biogen, Aduhelm, in 2021 to treat Alzheimer’s disease despite a lack of evidence that it is effective.
ALS, also sometimes known as Lou Gehrig’s disease, is a neurodewngerative disease that affects nerve cells in the brain, leading to weakness and paralysis.
The disease often begins with patients experiencing muscle twitching and weakness in one arm or leg followed by having difficulty swallowing or slurring speech.
Patients’ conditions eventually decline to a point at which they are unable to move, speak, eat or even breathe on their own.
According to an 2017 estimate from the Centers for Disease Control and Prevention, about 32,000 people in the U.S. live with ALS.
There is no cure, but some already approved treatments may help. It is always fatal, according to the ALS Association.