What is Qalsody or Tofersen for ALS?

Qalsody, also known as Tofersen, is the first treatment designed to target a genetic cause of ALS and there’s been some interesting updates with it in the past 2 years.

It works only for people who have a confirmed mutation in the SOD1 gene, a rare form that affects about 2% of all ALS patients. 

This guide explains in plain language what Qalsody is, how it works, who it’s for and how patients can access it in the U.S. and the U.K.

What is Qalsody or Tofersen for ALS

It’s not a traditional pill or biologic. Instead, it’s a type of treatment called an antisense oligonucleotide (ASO). You can think of an ASO as a tiny, smart piece of synthetic DNA that’s precisely engineered to find and intercept one specific genetic message in your body.

Qalsody’s homepage explains it in more detail

How does Qalsody work

In this type of ALS, the faulty SOD1 gene constantly sends out bad instructions (called mRNA) to your cells. These instructions build a toxic version of the SOD1 protein, which then poisons and kills your motor neurons.

Qalsody is designed to stop this. It works by finding those bad mRNA instructions and sticking to them. This signals the cell to destroy the instructions before the toxic protein can even be built.

By shutting down the source, the therapy aims to:

• Reduce the amount of toxic protein being made.
• Lower neurofilament light chain, which is a key marker in the blood that shows your nerve cells are being damaged.
• Slow down the disease’s progression, help preserve breathing, and potentially extend survival, especially when started early.

How is Qalsody Administered

It can’t be taken as a pill because it needs to reach your brain and spinal cord directly. 

Qalsody’s injected right into the cerebrospinal fluid.

The dosing is done in two stages:

• Loading Phase: You start with three doses, getting one injection every 14 days.
• Maintenance Phase: After that, you switch to one injection every 28 days.

Does Tofersen or Qalsody Cure ALS?

It’s crucial to understand that Qalsody cannot repair nerve cells that have already been damaged or died. 

It also only works for the small group of ALS patients who have the specific SOD1 gene mutation, not for any other form of the disease. Even in long-term studies, patients did not regain lost abilities; they just declined at a slower rate.

It can buy patients more time and slow down how fast their symptoms get worse, but it cannot reverse the damage that has already been done.

What does Qalsody actually help with then?

Here is a clear breakdown of the practical effects this treatment aims to have:

• It helps slow down the loss of your physical abilities, which can mean preserving your ability to walk, use your hands, and speak for a longer time.
• It helps protect your breathing strength, which is a critical part of managing ALS and improving quality of life.
• It may help you live longer by slowing the overall decline in your muscle and breathing function, especially if you start the treatment early.
• It works by protecting your nerve cells from the toxic damage that causes the disease. You won’t feel this happening, but this protective action is what leads to all the other benefits over time.

In simple terms, Qalsody helps by hitting the brakes on the disease, giving you more time with the strength and abilities you have now.

Is Qalsody FDA approved

It’s the first treatment that’s targeting a genetic cause of ALS to get approval.

The FDA granted accelerated approval because Qalsody was proven to lower a key blood marker called neurofilament light chain (NfL). Since NfL is a sign of nerve damage, lowering it is considered “reasonably likely” to predict a real benefit for patients. They used data from the Phase III Valour trial, which you can read about on its clinical trials page.

However, this approval is conditional. It relies on the results of an ongoing study (the ATLAS trial) to confirm that lowering this biomarker actually helps patients by slowing the disease or improving survival. If that trial fails to show a clear benefit, the FDA has the right to withdraw the approval.

Is Qalsody/Tofersen available in the UK?

The UK’s health regulator, the MHRA, granted this “marketing authorisation” on July 22, 2025. This approval means the treatment is now licensed in the UK and can be legally prescribed for patients with SOD1-ALS.

Can I Get Qalsody on the NHS?

Not yet.

Official approval from the MHRA is only the first hurdle; it does not automatically mean the treatment is funded and available on the NHS.

For Qalsody to become available to patients, it must go through a separate assessment process to secure NHS reimbursement. This is managed by bodies like the National Institute for Health and Care Excellence in England, which must decide if the treatment is a cost-effective option for the NHS to provide.

So, while the drug is approved in the UK, it is not yet funded on the NHS. The process to make it accessible to eligible patients is still underway.

Tofersen Cost

This is one of the few situations where the U.S. government has stepped in to ensure access. After the FDA granted Qalsody “Accelerated Approval” in 2023, the Centers for Medicare & Medicaid Services (CMS) issued a directive. This rule requires Medicare Advantage plans and private insurers to cover the treatment for its approved use.

This means that insurance companies cannot deny coverage by claiming the treatment is “experimental or investigational”. As a result, major private insurers, such as Aetna, now list Qalsody as “medically necessary”.

Can I Just Pay for Tofersen Myself?

Access to the drug is managed strictly through the official prescription and insurance authorization process.

When you see “private” access mentioned, this refers to patients using private health insurance plans, not paying for the drug directly out-of-pocket.

How do I get Qalsody or Tofersen in the US?

Getting coverage isn’t automatic. To be approved, a patient must meet the strict on-label criteria. Your neurologist must provide proof that you:

• Have a confirmed diagnosis of ALS.
• Have a confirmed SOD1 gene mutation (proven by a genetic test).
• Have adequate respiratory (breathing) function, often measured as an FVC above 50%.

Biogen runs a patient support program to help coordinate this genetic testing and the insurance authorization process.

Latest Research on Qalsody

Qalsody isn’t a cure, but it’s the first treatment that successfully attacks the root cause of this type of ALS.

Clinical studies have proven that it works by stopping the body from making the toxic protein that kills nerve cells .

This protects the nerves from damage and, as the combined evidence shows, successfully slows down the disease. This helps patients keep their muscle strength and breathing ability for a longer period.

The treatment’s generally safe, but it has known risks.

Most side effects are minor, like headaches from the spinal tap procedure used to deliver the drug. However, a small number of patients have experienced serious side effects, including inflammation of the spinal cord.

A major new trial is now underway to see if Tofersen can even prevent or delay the disease in people who have the faulty gene but don’t have any symptoms yet. If you want to read on specific studies, check out the table below:

Is Qalsody better then Stem Cell Therapy to treat ALS?

Qalsody and stem cells are two completely different strategies. Qalsody is a targeted genetic drug designed to fix a specific problem in a very small group of ALS patients.

Stem cell therapy is a cell-based treatment that acts as a support system to protect nerve cells and is being tested for the broader ALS population.

Who are the treatments aimed at?

• Qalsody: This treatment is only for the small group of ALS patients (about 2% of all cases) who have a confirmed faulty SOD1 gene. It does not work for any other form of ALS.
• Stem Cell Therapy: This is being tested for the general ALS population, regardless of their genetics. Most of the major trials have focused on patients with sporadic ALS.

How Does Qalsody work compared to Stem Cells?

• Qalsody: This drug attacks the root cause of the disease. In SOD1-ALS, the faulty gene creates a toxic protein that poisons and kills motor neurons . Qalsody is a piece of synthetic DNA that finds the bad genetic instructions and destroys them before the toxic protein can be built .
• Stem Cell Therapy: This therapy works as a protective support system. The stem cells are not believed to replace your lost nerve cells. Instead, they are injected into the spinal fluid where they release a flood of healing proteins and neurotrophic factors. These substances calm harmful inflammation and act as a protective shield for your remaining, healthy motor neurons, helping them survive longer.

Do either treatments cure ALS?

Both approaches are designed to slow the disease down to help preserve a patient’s function for longer, but neither can stop the disease completely or reverse the damage that has already been done.

Are they approved?

• Qalsody: Yes. Based on its powerful effect on the NfL biomarker, it received “Accelerated Approval” in the US and full approval in the UK for SOD1 patients .
• Stem Cell Therapy:No. It is not approved in the US or Europe. One specific therapy, Neuronata-R, has “conditional approval” only in South Korea.

What Are the Risks?

• Qalsody (Tofersen): The treatment is generally safe, but it carries a known risk of serious neurological side effects in a small number of patients. This includes inflammation of the spinal cord or the brain lining.

• Stem Cell Therapy: The trials have consistently shown a strong safety record. Most side effects are considered mild and are related to the spinal tap procedure itself, not the cells.