What to Know About Relyvrio, the Controversial New FDA-Approved Drug for Treating ALS?

Photo credit: koto_feja - Getty Images
Photo credit: koto_feja - Getty Images

The Food and Drug Administration (FDA) has approved a new drug to treat amyotrophic lateral sclerosis (ALS)—and it’s controversial.

The medication, called Relyvrio, was given the green light by the FDA despite an analysis by the agency that found that there is not good evidence that the drug will help slow progression of the disease or help patients live longer. The FDA said in a summary memorandum about the drug that there was “residual uncertainty about the evidence of effectiveness.” However, the agency continued, “given the serious and life-threatening nature of ALS and the substantial unmet need, this level of uncertainty is acceptable in this instance.”

The memorandum noted that the benefits of taking the drug outweigh potential risks because it seems relatively safe to take.

ALS, aka Lou Gehrig’s disease, is a progressive nervous system disease that impacts nerve cells in the brain and spinal cord, according to the Mayo Clinic. It causes loss of muscle control, along with muscle twitching and weakness and slurred speech. It eventually affects the muscles that are needed to move, speak, eat, and breathe. ALS is fatal.

The approval comes after several doctors who treat patients with ALS pleaded with the FDA in a letter to approve Relyvrio, which has the scientific name AMX0035.

The letter acknowledged that data show that the drug may have “incremental” benefits, but it said that “they are meaningful to us as ALS specialists and to our patients.” The letter continued, “it can mean a difference between walking up the stairs or being restricted to a floor of your home. It can mean being able to feed yourself versus needing help to just cut your food. This means more time for our patients with the people they love.”

A phase 3 trial for the medication is currently underway, and the letter acknowledged this. “The FDA has a choice to make. FDA could choose to not approve AMX0035 now and wait for the confirmatory phase 3 trial, which is already underway,” the letter said. “This would mean that if the second trial confirms the positive findings, thousands of people with ALS would have been deprived of this life-changing therapy and pass away due to this fatal disease. If the FDA does the right thing and approves now, and the phase 3 trial fails to replicate, people with ALS may have been treated with an ineffective but a safe drug which would not have caused any substantive harm.”

To add to the controversy, the drug will cost $158,000 a year, according to The New York Times. But what’s the deal with Relyvrio and what do doctors think? Here’s what you need to know.

What is Relyvrio, exactly?

Relyvrio is a combination of two existing drugs—sodium phenylbutyrate and taurursodiol, per the FDA. It’s designed to help slow the progression of ALS and add more time to someone’s life, but there’s a little mystery surrounding the drug.

“We don’t know” how the medication works, says Jamie Alan, Ph.D., associate professor of pharmacology and toxicology at Michigan State University. She points to the manufacturer insert which basically says the same thing: “The mechanism by which Relyvrio exerts its therapeutic effects in patients with ALS is unknown.”

The medication can be taken by mouth by combining one packet with eight ounces of room-temperature water, per the FDA, or it can be given through a feeding tube.

What does the data show?

While the FDA said in its memorandum that evidence to support the use of Relyvrio was lacking, there is some data to suggest it can work.

A 24-week randomized double-blind, placebo-controlled, parallel-group study of 137 adult patients with ALS found that patients treated with Relyvrio had a “slower rate of decline on a clinical assessment of daily functioning compared to those receiving a placebo,” according to the FDA. Patients who took the medication also survived an average of five to six months longer than those who took a placebo, the FDA said.

There are some potential side effects, but they’re mostly minor. Those include:

  • Diarrhea

  • Stomach pain

  • Nausea

  • Upper respiratory tract infection

What doctors think

In general, doctors are in favor of this. “I’m excited for our patients,” says Amit Sachdev, M.D., the director of the division of neuromuscular medicine at Michigan State University. ALS “really is a horrible disease that needs a cure,” he adds.

Dr. Sachdev says it’s especially important to have another treatment for ALS given that “the two current medications [to treat ALS] do not meaningfully change the course of the disease.”

But Alan says it’s “pretty rare” for a medication to be approved this way. “I can see both sides,” she says. “The cost is considerable at over $150,000 per year. However, ALS is a deadly disease, and typically leads to death in two to five years. An extra five months for a patient could be very meaningful.”

Amylyx Pharmaceuticals, which makes Relyvrio, told The New York Times that most patients would pay little to nothing for treatment because insurance will cover the rest. The company also says they plan to provide the medication for free for uninsured patients who can’t afford it. However, the price tag is much, much higher than recommended by the Institute for Clinical and Economic Review, a nonprofit group that evaluates the value of medicines—they estimated the cost should be $9,100 to $30,700...if the drug actually works. The group also noted that, if it was priced similarly to fellow IV ALS medication edaravone, which is $169,000 a year, it would “far exceed typical cost-effectiveness thresholds” based on the clinical data available.

While Dr. Sachdev is excited about the news, he said he would “like to see the phase 3 data about the efficacy.”

His advice for ALS patients: “Talk to your provider. Each medication decision is very tailored and personalized.”

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