FDA Approves New Treatment for Amyotrophic Lateral Sclerosis

On September 29, 2022, the US Food and Drug Administration (FDA) approved¹ combination sodium phenylbutyrate/taurursodiol, known as the branded name Relyvrio, for patients with amyotrophic lateral sclerosis (ALS).

ALS, commonly known as Lou Gehrig’s disease, is a fatal, progressive neuromuscular disease that impairs voluntary muscle control.² About 5000 patients in the United States are diagnosed with the disease each year.¹

“This approval provides another important treatment option for ALS, a life-threatening disease that currently has no cure,” said Billy Dunn, MD, director, Office of Neuroscience, FDA’s Center for Drug Evaluation and Research.

The drug was investigated in a multicenter, randomized, double-blind, parallel-group study³ in which 137 adults received either Relyvrio or placebo for 24 weeks. Compared to the placebo group, patients receiving Relyvrio had slower declines in clinical assessments of daily functioning, according to the findings.

With a 6 to 4 vote, the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee recommended against approving Relyvrio in March, saying there was insufficient evidence to support the drug’s efficacy. However, a new post-hoc analysis of the study showed patients receiving Relyvrio also had longer rates of overall survival, prompting the committee to vote 7 to 2 to recommend approval in early September.

Relyvrio is administered orally at a dosage of 1 packet (3 g sodium phenylbutyrate and 1 g taurursodiol) per day for the first 3 weeks of treatment, after which the dosage increases to 2 packets per day. Packet contents can be mixed into room temperature water and given with food or administered through feeding tubes, if necessary.

Per the press release, “The most common adverse reactions experienced with Relyvrio were diarrhea, abdominal pain, nausea, and upper respiratory tract infection. Relyvrio contains taurursodiol, a bile acid, which may cause worsening diarrhea in patients with disorders that interfere with bile acid circulation.”

Relyvrio was developed by Amylyx Pharmaceuticals Inc. Designated an orphan drug, Relyvrio is the first agent approved for ALS since edaravone (Radicava) in 2017.

References:

1. FDA approves new treatment option for patients with ALS. News release. US Food and Drug Administration; September 29, 2022. Accessed September 30, 2022. https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-option-patients-als
2. Mayo Clinic Staff. Amyotrophic lateral sclerosis (ALS). Mayo Clinic. Updated February 22, 2022. Accessed September 30, 2022.
3. Paganoni S, Macklin EA, Hendrix S, et al. Trial of sodium phenylbutyrate-taurursodiol for amyotrophic lateral sclerosis. N Engl J Med. 2020;383(10):919-930. doi:10.1056/NEJMoa1916945