Who is Eligible for Qalsody (Tofersen) ALS Treatment?

Tofersen (sold under the brand name Qalsody) is a targeted therapy approved for adults with amyotrophic lateral sclerosis (ALS) who have a mutation in the SOD1 gene ^[1][2]. To qualify for this treatment, a person must undergo clinical genetic testing that confirms they have a pathogenic (disease-causing) or likely pathogenic SOD1 genetic variant ^[3][4]. Because tofersen works by targeting the biological effects of this specific mutation, it is not an effective treatment for individuals with other forms of ALS ^[5].

It is important to understand that tofersen is designed to slow the progression of the disease, not to cure it ^[6][7].

The Importance of Genetic Testing

Historically, genetic testing for ALS was primarily offered to people with a known family history of the disease. The approval of targeted therapies like tofersen has changed this approach: today, genetic testing is recommended for all individuals upon an ALS diagnosis ^[2][4].

Even if you do not have a known family history of ALS, a genetic panel can determine if your disease is driven by the SOD1 mutation (which accounts for roughly 2% of all ALS cases) or other known genetic variants ^[3]. Getting tested is usually a simple process, typically requiring only a blood draw or a saliva sample coordinated by your neurologist or a genetic counselor. Identifying the specific genetic cause is the only way to know if you are eligible for tofersen or specialized clinical trials ^[4].

How Tofersen Works and Its Approval Status

In people with an SOD1 mutation, the body produces a toxic form of the SOD1 protein, which builds up and damages motor neurons (nerve cells) ^[5][8]. Tofersen is an antisense oligonucleotide ^[1]. It works by binding to the genetic instructions for the SOD1 protein, essentially telling the body to stop producing it ^[6][8].

Tofersen received FDA Accelerated Approval based on its ability to significantly reduce the levels of a biomarker called neurofilament light chain (NfL) in clinical trials ^[9][10]. NfL is a protein released into the blood and spinal fluid when nerve cells are damaged; a reduction in NfL strongly suggests the drug is helping to slow down nerve injury ^[11][6]. Because this was an accelerated approval based on a biomarker rather than physical symptoms, ongoing confirmatory clinical trials are currently underway to verify its long-term clinical benefits on muscle function and survival ^[1][9].

How Tofersen Is Administered

Because drugs often have difficulty crossing from the bloodstream into the brain and spinal cord, tofersen must be delivered directly into the fluid surrounding the central nervous system ^[12]. It is administered via an intrathecal injection, which is commonly known as a spinal tap or lumbar puncture ^[13][12].

• The Procedure: A specialized healthcare provider uses a needle to inject the medication directly into the spinal canal ^[14]. To make this more comfortable, doctors typically use a local anesthetic to numb the area, and some patients may receive medication to help them relax.
• The Schedule: The treatment typically begins with three initial “loading” doses given two weeks apart, followed by “maintenance” doses given once every 28 days ^[15]. Committing to a monthly spinal tap is a significant physical and emotional undertaking that should be discussed thoroughly with your care team.

Side Effects and Ongoing Monitoring

While clinical trials showed that the potential benefits of slowing disease progression outweighed the risks for many patients, tofersen and the repeated spinal taps do carry side effects that require continuous monitoring by your neurology team ^[15][16].

Common Side Effects:
The most frequent issues are often related to the lumbar puncture procedure itself or the body’s reaction to the drug, including ^[11][16]:

• Pain at the injection site or back pain
• Post-lumbar puncture headaches
• Fatigue and muscle/joint aches

Rare but Serious Risks:
Your care team will closely monitor you for rarer, severe neurological reactions, which can include ^[15][11]:

• Myelitis or Chemical Meningitis: Inflammation of the spinal cord or the lining of the brain and spinal cord.
• Papilledema: Increased pressure in the fluid around the brain, which can cause swelling of the optic nerve and lead to vision changes.