Phenylbutanoic acid
As of the edition of 20 October 2026, Phenylbutanoic acid is a small molecule: marketed, first approved in 1996 (US); no US protection of its own is listed.
Sources: FDA Orange Book and Purple Book, other approval registers, ClinicalTrials.gov, ChEMBL.
The drug
- Status
- Marketed; latest approval 2012
- Kind
- Small molecule
- Brand name
- Buphenyl
- First approved
- 30 April 1996 (US)
- Approvals on record
- 15 in 3 regions
- Holder of the most recent approval
- Zevra Therapeutics; 7 holders in all
- Registered trials
- 32, 6 stopped early
- Disease areas
- Nervous system; Cancer; Inherited and neonatal; Nutrition and metabolism; Blood and lymph; Immune system
US protection
No US protection of its own is listed.
The FDA registers list no drug-substance patent or exclusivity of its own that counts for this drug.
Amylyx Pharmaceuticals holds a later exclusivity on its own new formulation or combination product, ending 2029; it does not protect the original drug.
This is the US only.
Registered trials
| Phase | Trials | Completed | Active | Stopped early |
|---|---|---|---|---|
| Phase not stated | 3 | 2 | 0 | 0 |
| Phase 1 | 9 | 6 | 2 | 1 |
| Phase 2 | 17 | 10 | 1 | 5 |
| Phase 3 | 2 | 2 | 0 | 0 |
| Phase 4 | 1 | 1 | 0 | 0 |
| All trials | 32 |
Who has held its approvals
| Company | Role | Years |
|---|---|---|
| Medicis Pharmaceutical | Earlier holder | 1996 to now |
| Immedica Pharma | Applicant | 1999 to now |
| Amgen | Acquired holder and Lead sponsor of trials | 2009 to now |
| Eurocept | Later holder | 2013 to now |
| Medunik | Later holder | 2022 to now |
| Zevra Therapeutics | Later holder | 2022 to now |