Qalsody is First Drug for Rare Form of ALS Approved by FDA

The US Food and Drug Administration (FDA) has approved Qalsody, a new drug to treat a form of amyotrophic lateral sclerosis (ALS) associated with a rare genetic mutation.

Qalsody (tofersen) will target a gene known as SOD1 that produces an enzyme called superoxide dismutase 1. They enzyme plays a crucial role in protecting the body’s cells from damaging oxidative stress. A mutation of the SOD1 creates a misfolded form of the enzyme triggering the nerve cell dysfunction and death associated with ALS. 

Studies suggest that this inherited mutation is a major contributor to a rare form of ALS that runs in families. Although familial ALS accounts for tiny percentage of all ALS cases, the study of SOD1 mutations has provided valuable insights into the underlying mechanisms of ALS in general, the FDA said in a release on its website. 

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Fast Track Approval

To obtain approval, researchers conducted a study on 147 patients, randomly assigned to receive either the drug or a placebo. The participants were 43 percent female; 57 percent male; 64 percent white; and 8 percent Asian. The average age was 49.8 years, ranging from 23 to 78 years.

Subjects who received Qalsody showed a reduction in plasma NfL, a protein that serves as marker for nerve damage. All subgroups receiving the drug showed improvement, even long-term patients and those already taking other ALS medications. However, the drug did not significantly slow the progression of the disease or improve symptoms. The most common side effects were pain and increased cerebrospinal fluid.

Despite uncertain clinical benefits, Qalsody received a priority review and a fast track drug designation. But the FDA said they were still evaluating the drug’s safety and effectiveness with ongoing studies. They also pointed to a phase 3 trial  currently underway to test whether Qalsody can prevent people with the SOD1 gene mutation from developing ALS symptoms in the first place.

Delivery and Cost

Qalsody will be injected into the spine in three doses administered every two weeks, followed by one maintenance dose every four weeks. Doctors will monitor each patient’s blood for NfL to see how well the treatment is working. Biogen, the pharmaceutical company bringing the drug to market, stated that the price of Qalsody will be similar to other approved treatments for ALS. One therapy approved last year costs about $160,000 annually. 

ALS is a progressive neurological disease that affects the nerve cells responsible for controlling voluntary muscles. Symptoms for all forms of ALS include muscle weakness, fatigue and difficulty walking, speaking and swallowing. And there is no known cure for any form.

ALS overall is relatively rare, affecting between 16,000 and 32,000 Americans, according to the Centers for Disease Control and Prevention (CDC). SOD1-ALS has been diagnosed in only about 500 patients in the US.