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NaPBA
NaPBA (sodium phenylbutyrate) reduces ammonia levels by providing an alternative pathway for nitrogen excretion through conjugation with glutamine.
NaPBA (sodium phenylbutyrate) reduces ammonia levels by providing an alternative pathway for nitrogen excretion through conjugation with glutamine. Used for Urea cycle disorders (hyperammonemia management), Acute hyperammonemic encephalopathy.
At a glance
| Generic name | NaPBA |
|---|---|
| Also known as | GT4P, Glyceryl tri-(4-phenylbutyrate), Sodium phenylbutyrate |
| Sponsor | Amgen |
| Drug class | Ammonia scavenger |
| Modality | Small molecule |
| Therapeutic area | Metabolic/Genetic Disorders |
| Phase | FDA-approved |
Mechanism of action
NaPBA is a prodrug that is metabolized to phenylacetate, which conjugates with glutamine via the enzyme phenylacetyl-CoA:glutamine-N-acetyltransferase to form phenylacetylglutamine. This conjugate is readily excreted in the urine, effectively removing excess nitrogen and reducing hyperammonemia. This mechanism bypasses the defective urea cycle, making it useful in patients with urea cycle disorders.
Approved indications
- Urea cycle disorders (hyperammonemia management)
- Acute hyperammonemic encephalopathy
Common side effects
- Nausea
- Vomiting
- Abdominal pain
- Headache
- Syncope
Key clinical trials
- To Evaluate the Safety of Long-term Use of HPN-100 in the Management of Urea Cycle Disorders (UCDs) (PHASE4)
- Study of the Safety, Pharmacokinetics and Efficacy of HPN-100, in Pediatric Subjects With Urea Cycle Disorders (UCDs) (PHASE3)
- Study of the Safety and Tolerability of HPN-100 Compared to Sodium Phenylbutyrate in Children With Urea Cycle Disorders (PHASE2)
- Dose-Escalation Safety Study of HPN-100 to Treat Urea Cycle Disorders (PHASE2)
- Study of the Safety of HPN (Hyperion)-100 for the Long-Term Treatment of Urea Cycle Disorders (Treat UCD) (PHASE3)
- Efficacy and Safety of HPN-100 for the Treatment of Adults With Urea Cycle Disorders (PHASE3)
- Study of Glycerol Phenylbutyrate & Sodium Phenylbutyrate in Phenylbutyrate Naïve Patients With Urea Cycle Disorders (UCDs) (PHASE4)
- A Study of Glyceryl Tri-(4-phenylbutyrate) Administered Orally as a Single Dose, and Twice Daily for Seven Consecutive Days to Subjects With Hepatic Impairment With Cirrhosis and to a Control Group (PHASE1)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- NaPBA CI brief — competitive landscape report
- NaPBA updates RSS · CI watch RSS
- Amgen portfolio CI