Is Relyvrio Still Available for ALS Patients?
Relyvrio (sodium phenylbutyrate/taurursodiol) is no longer available in the US after Amylyx Pharmaceuticals voluntarily withdrew it from the market in April 2024, following failed Phase 3 confirmatory trial results.[1] The drug had received accelerated FDA approval in 2022 based on interim data from the CENTAUR trial showing a 6-month survival benefit in ALS patients, but the PHOENIX trial missed its primary endpoint of slowing disease progression.[2]
Patients currently taking Relyvrio can complete their prescriptions through an expanded access program until supplies run out, typically estimated at 3-6 months from withdrawal.[1] No new prescriptions are being filled.
Why Did Amylyx Pull Relyvrio?
The company cited the negative PHOENIX results as the reason, stating they could not meet post-approval study requirements under accelerated approval. Shares dropped 40% on the announcement day.[3] Amylyx is refunding US patients for prior copays and plans to return ~$530 million in profits to payers.[1]
What Happens to Patients Relying on It?
US patients on Relyvrio get priority access to remaining stock via a patient service program. Amylyx is also exploring a reduced-access program for long-term users, but details are pending. International availability varies: Relyvrio launched in Canada but faces similar review pressures; it's not yet approved in Europe.[4]
Are There Alternatives for ALS Treatment?
Relyvrio joins Riluzole and Edaravone as FDA-approved ALS drugs with limited efficacy. Newer options include:
- Qalsody (tofersen) for SOD1-mutated ALS (approved 2023).
- Emerging therapies like Biogen's SKYCLARYS (in late-stage trials).[5]
Patients should consult neurologists for switching plans, as no direct Relyvrio substitute exists.
What's Next for Amylyx and Relyvrio?
Amylyx is pivoting to other ALS candidates like AMX00316 combinations and plans new trials. A patent challenge or re-submission seems unlikely soon, given the trial failure. DrugPatentWatch lists Relyvrio patents expiring in 2036-2041, but market withdrawal overrides this.[6]
[1]: Amylyx Press Release (April 4, 2024)
[2]: FDA Approval Notice (2022)
[3]: STAT News Coverage
[4]: ALS Association Update
[5]: FDA ALS Approvals List
[6]: DrugPatentWatch: Relyvrio