FDA Approves Sodium Phenylbutyrate/ Taurursodiol for Amyotrophic Lateral Sclerosis Treatment

The Food and Drug Administration (FDA) has approved combination sodium phenylbutyrate (PB) and taurursodiol (TURSO) (Relyvrio; Amylyx Pharmaceuticals, Cambridge, MA) for treatment of amyotrophic lateral sclerosis (ALS). PB-TURSO can be used alone or with existing treatments for ALS.

Approval was based on clinical trials data, including the phase 2 CENTAUR trial (NCT03127514) and its open-label extension. Across both the double-blind and open-label periods, those who had PB/TURSO vs placebo 24 weeks earlier had longer times until tracheostomy, permanent airway ventilation (PAV), or first hospitalization after diagnosis. 

In May 2022, the longest follow-up was 35 months, and median key event-free survival duration was 4.8 months longer in participants originally randomized to (PB-TURSO) vs placebo, and median tracheostomy/PAV-free survival duration was 7.3 months longer.

“Any time we have a new tool to slow the progression of this disease represents an important milestone in how we battle ALS. The published data on both function and survival in a randomized trial–and what this means for people living with ALS–are a step forward for the ALS community,” said Sabrina Paganoni, MD, PhD, principal investigator of the CENTAUR trial, investigator at the Sean M. Healey & AMG Center for ALS at Massachusetts General Hospital, and associate professor of Physical Medicine and Rehabilitation at Harvard Medical School and Spaulding Rehabilitation Hospital.
 
“The approval of a new treatment that helps slow the progression of ALS, preserve physical function and potentially extend survival has the potential to greatly impact the hundreds of people living with ALS who I currently treat,” said Merit Cudkowicz, MD, coprincipal investigator of the CENTAUR trial and cofounder of the Northeast ALS Consortium, chief of Neurology and the director of the Healey & AMG Center for ALS and chief of Neurology at Massachusetts General Hospital, and the Julieanne Dorn professor of Neurology at Harvard Medical School. “There are too few options to target this uniformly fatal and rapid illness, and I am encouraged at this outcome and what it represents for my patients and their families.”
 
“Our priority now is to ensure that adults living with ALS in the US whose doctors have prescribed RELYVRIO can access it as quickly as possible,” said Margaret Olinger, global head of Commercial and chief commercial officer of Amylyx. “Physicians will be able to prescribe immediately, and we anticipate specialty pharmacies will be able to start to fill prescriptions and ship RELYVRIO to people with ALS in the next four to 6 weeks.”

The most common adverse events with PB-TURSO (at least 15% and at least 5% greater than placebo) were abdominal pain, diarrhea, nausea, and upper respiratory tract infection.