A Phase 4 interventional study of RAVICTI and NaPBA in Urea Cycle Disorder, sponsored by Amgen. Completed at 11 sites in 4 countries. Open to participants aged Up to 99 Years. Per ClinicalTrials.gov, last updated 2024-07-01.
Sponsored by Amgen · Phase 4, Interventional, and Treatment
Among 10 studies in Urea Cycle Disorders, Inborn by Amgen — none open to participants now, none under way, none of them phase 3. Urea Cycle Disorders, Inborn · Amgen.
Among the 10 studies in Urea Cycle Disorders, Inborn by Amgen, this one is the only one that started in 2018, is one of 3 in phase 4, and was the 10th registered.
66 studies on the registry are indexed under Urea Cycle Disorders, Inborn; 14 are open to participants now.
Browse Urea Cycle Disorders, Inborn studies →None of the 10 studies in Urea Cycle Disorders, Inborn by Amgen is open now. The open studies under Urea Cycle Disorders, Inborn, anywhere →
Of the 12 Urea Cycle Disorders, Inborn studies recruiting now, 5 (42%) set no upper age limit and 7 (58%) stop at 75 or younger; 11 take children under 18; 4 take healthy volunteers.
This study: Up to 99 Years · all sexes · no healthy volunteers.
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10 studies; the count open now beside each. This study's row is marked.
First in 2006; this study’s year is marked. 1 started in 2018.
This study's enrollment of 16 is close to the median of 17 across 39 interventional studies indexed under Urea Cycle Disorders, Inborn.
Median enrollment 27 across the 9 interventional studies, 203 across the 1 observational. Of the 10 that completed or were terminated, 9 (90%) have results posted.
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Amgen is the lead sponsor of 1,047 studies on the registry; 51 are open to participants now.
Of its 246 completed or terminated interventional studies of FDA-regulated products, 166 (67%) have results posted.
None of the studies under way reaches primary completion within a year.
Among the 10 studies in Urea Cycle Disorders, Inborn by Amgen, from their registry updates:
Nothing recorded among them since 2026-09-25.
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This is a randomized, controlled, open-label parallel arm study to assess the safety, tolerability, pharmacokinetics and ammonia control, of RAVICTI® as compared to Sodium phenylbutyrate (NaPBA) in urea cycle disorder subjects not currently or previously chronically treated with phenylacetic acid (phenylacetate; PAA) prodrugs. The study design will include: 1) Baseline Period; 2) Initial Treatment Period; 3) a RAVICTI only Transition Period 4) a RAVICTI only Maintenance Period; and 5) a RAVICTI only Safety Extension Period. The study will run for approximately 25 weeks.
Study acquired from Horizon in 2024.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Confirmed diagnosis is determined via enzymatic, biochemical, or genetic testing.
Exclusion Criteria:
Temporary use of NaPBA for acute management of a hyperammonemic crisis in the past is acceptable.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Initial Treatment, Maintenance, Safety Extension Periods: RAVICTI, Oral Liquid Product 17.5 mL maximum total daily dose. Dosing will be based on participants disease and treatment status at entry to the study.
Drug: RAVICTI
Initial Treatment Period: NaPBA dosing based on participants disease and treatment status at entry to the study. Transition, Maintenance, Safety Extension Periods: RAVICTI, Oral Liquid Product 17.5 mL maximum total daily dose. Dosing will be based on participants disease and treatment status at entry to the study.
Drug: NaPBA
RAVICTI, Oral Liquid Product 17.5 mL maximum total daily dose
Also known as: Glycerol phenylbutyrate, GPB, HPN-100
* NaPBA in patients weighing \< 20 Kg - 600 mg/Kg, maximum total daily dose * NaPBA in patients weighing \> 20 Kg - 13 g/m2, maximum total daily dose
Also known as: Sodium phenylbutyrate
Rate of Treatment Success (Percentage of Participants Defined as Treatment Success at Week 4) During the Initial Treatment Period
A participant was considered a Treatment Success for the assigned treatment arm if the participant had not experienced an unprovoked hyperammonemic crisis (HAC) (i.e., a HAC that cannot be attributed to one or more specific precipitating factors such as infection, intercurrent illness, diet noncompliance, treatment noncompliance, etc.) on the assigned treatment and had met at least 2 of the following 3 criteria: * Had absolute values at the 3 time points (pre-dose, after dose at 4 hours and 8 hours) of plasma ammonia levels which do not exceed ULN at the Week 4(End of Initial Treatment Period visit) * Had normal (≤ ULN) glutamine levels at the Week 4 (End of Initial Treatment Period visit at the time point Zero Hour. * Had normal (≤ ULN) essential amino acids including branched chain amino acid levels (threonine, phenylalanine, methionine, lysine, leucine, isoleucine, histidine, valine) at the End of Initial Treatment Period visit at time point Zero Hour.
Time frame: Week 4
Rate of Drug Discontinuations (Percentage of Participants Who Discontinued Study Drug) Due to Any Reason in the Initial Treatment Period
Time frame: Baseline through Week 4
Change From Baseline in Fasting Plasma Ammonia Levels During the Initial Treatment Period
Time frame: Baseline, Initial Treatment Period Week 1, Week 2, Week 3, Week 4 (0, 4, 8 hours post dose)
Plasma Ammonia Area Under the Curve (AUC) 0 to 8h at the End of the Initial Treatment Period
Time frame: Week 4: hour 0 (predose), and hours 4 and 8 postdose
Peak Plasma Concentration (Cmax) of Ammonia at the End of the Initial Treatment Period
Time frame: Week 4: hour 0 (predose), and hours 4 and 8 postdose
| Milestone | RAVICTI -> RAVICTI | NaPBA -> RAVICTI |
|---|---|---|
| Started | 11 | 5 |
| Completed | 11 | 5 |
| Not completed | 0 | 0 |
| Milestone | RAVICTI -> RAVICTI | NaPBA -> RAVICTI |
|---|---|---|
| Started | 0 | 5 |
| Completed | 0 | 5 |
| Not completed | 0 | 0 |
| Milestone | RAVICTI -> RAVICTI | NaPBA -> RAVICTI |
|---|---|---|
| Started | 11 | 5 |
| Completed | 10 | 5 |
| Not completed | 1 | 0 |
| Withdrew: Withdrawal by parent/guardian | 1 | 0 |
| Milestone | RAVICTI -> RAVICTI | NaPBA -> RAVICTI |
|---|---|---|
| Started | 10 | 5 |
| Completed | 8 | 5 |
| Not completed | 2 | 0 |
| Withdrew: Adverse event | 1 | 0 |
| Withdrew: Did not return to study visit | 1 | 0 |
A participant was considered a Treatment Success for the assigned treatment arm if the participant had not experienced an unprovoked hyperammonemic crisis (HAC) (i.e., a HAC that cannot be attributed to one or more specific precipitating factors such as infection, intercurrent illness, diet noncompliance, treatment noncompliance, etc.) on the assigned treatment and had met at least 2 of the following 3 criteria: * Had absolute values at the 3 time points (pre-dose, after dose at 4 hours and 8 hours) of plasma ammonia levels which do not exceed ULN at the Week 4(End of Initial Treatment Period visit) * Had normal (≤ ULN) glutamine levels at the Week 4 (End of Initial Treatment Period visit at the time point Zero Hour. * Had normal (≤ ULN) essential amino acids including branched chain amino acid levels (threonine, phenylalanine, methionine, lysine, leucine, isoleucine, histidine, valine) at the End of Initial Treatment Period visit at time point Zero Hour.
| percentage of participants | RAVICTI | NaPBA |
|---|---|---|
| Rate of Treatment Success (Percentage of Participants Defined as Treatment Success at Week 4) During the Initial Treatment Period | 81.8 | 80.0 |
| percentage of participants | RAVICTI | NaPBA |
|---|---|---|
| Rate of Drug Discontinuations (Percentage of Participants Who Discontinued Study Drug) Due to Any Reason in the Initial Treatment Period | 0 | 0 |
| µmol/L | RAVICTI | NaPBA |
|---|---|---|
| Week 1 | 6.5 ± 21.16 | 0.0 ± 10.12 |
| Week 2 | 25.5 ± 59.88 | -10.4 ± 10.17 |
| Week 3 | 7.4 ± 35.91 | -10.9 ± 6.40 |
| Week 4: 0 hour | 2.1 ± 15.52 | -0.3 ± 8.49 |
| Week 4: 4 hours postdose | 2.6 ± 23.49 | -1.1 ± 8.68 |
| Week 4: 8 hours postdose | 23.4 ± 62.09 | -0.7 ± 7.37 |
| µmol*h /L | RAVICTI | NaPBA |
|---|---|---|
| Plasma Ammonia Area Under the Curve (AUC) 0 to 8h at the End of the Initial Treatment Period | 331.8 ± 342.79 | 258.9 ± 153.35 |
| µmol/L | RAVICTI | NaPBA |
|---|---|---|
| Peak Plasma Concentration (Cmax) of Ammonia at the End of the Initial Treatment Period | 60.2 ± 78.47 | 38.1 ± 18.91 |
Collected over All-cause mortality: from enrollment through the end of study up to 25 weeks plus 30 days. Adverse events: from the first dose through the last dose of study drug in a given period, plus 30 days from the last dose taken, regardless of period. Overall mean time on treatment for the Initial Treatment Period was 30.7 days (RAVICTI) and 26.0 days (NaPBA), for the Transition Period was 8.0 days, for the Maintenance Period was 54.4 days, and for the Safety Extension Period was 84.6 days.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Initial Treatment Period: RAVICTI | 0/11 (0%) | 2/11 (18.2%) | 6/11 (54.5%) |
| Initial Treatment Period: NaPBA | 0/5 (0%) | 0/5 (0%) | 2/5 (40%) |
| Transition Period: RAVICTI | 0/5 (0%) | 1/5 (20%) | 1/5 (20%) |
| Maintenance and Safety Periods Combined | 0/16 (0%) | 3/16 (18.8%) | 8/16 (50%) |
| Event | Initial Treatment Period: RAVICTI | Initial Treatment Period: NaPBA | Transition Period: RAVICTI | Maintenance and Safety Periods Combined |
|---|---|---|---|---|
| PyrexiaGeneral disorders | 0/11 | 0/5 | 1/5 | 1/16 |
| Hyperammonaemic crisisMetabolism and nutrition disorders | 2/11 | 0/5 | 0/5 | 2/16 |
| NeutropeniaBlood and lymphatic system disorders | 1/11 | 0/5 | 0/5 | 1/16 |
| HyperammonaemiaMetabolism and nutrition disorders | 1/11 | 0/5 | 0/5 | 1/16 |
| Bone marrow failureBlood and lymphatic system disorders | 0/11 | 0/5 | 0/5 | 1/16 |
| Event | Initial Treatment Period: RAVICTI | Initial Treatment Period: NaPBA | Transition Period: RAVICTI | Maintenance and Safety Periods Combined |
|---|---|---|---|---|
| ThrombocytopeniaBlood and lymphatic system disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| HypoacusisEar and labyrinth disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| Vision blurredEye disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| Abdominal painGastrointestinal disorders | 0/11 | 1/5 | 0/5 | 1/16 |
| DysphagiaGastrointestinal disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| NauseaGastrointestinal disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| FatigueGeneral disorders | 0/11 | 1/5 | 0/5 | 0/16 |
| Fibula fractureInjury, poisoning and procedural complications | 0/11 | 1/5 | 0/5 | 0/16 |
| Ligament sprainInjury, poisoning and procedural complications | 0/11 | 1/5 | 0/5 | 0/16 |
| Alanine aminotransferase increasedInvestigations | 0/11 | 0/5 | 1/5 | 0/16 |
| Age, Customized(Participants) | RAVICTI -> RAVICTI | NaPBA -> RAVICTI | Total |
|---|---|---|---|
| < 2 months | 1 | 0 | 1 |
| 2 months - < 2 years | 4 | 0 | 4 |
| 2 years - 12 years | 1 | 3 | 4 |
| > 12 - 16 years | 0 | 0 | 0 |
| >= 17 years | 5 | 2 | 7 |
| Sex: Female, Male(Participants) | RAVICTI -> RAVICTI | NaPBA -> RAVICTI | Total |
|---|---|---|---|
| Female | 4 | 3 | 7 |
| Male | 7 | 2 | 9 |
| Ethnicity (NIH/OMB)(Participants) | RAVICTI -> RAVICTI | NaPBA -> RAVICTI | Total |
|---|---|---|---|
| Hispanic or Latino | 4 | 2 | 6 |
| Not Hispanic or Latino | 7 | 3 | 10 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | RAVICTI -> RAVICTI | NaPBA -> RAVICTI | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 0 | 0 | 0 |
| White | 10 | 5 | 15 |
| More than one race | 1 | 0 | 1 |
| Unknown or Not Reported | 0 | 0 | 0 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: Data sharing requests relating to this study will be considered beginning 18 months after the study has ended and either 1) the product and indication have been granted marketing authorization in both the US and Europe or 2) clinical development for the product and/or indication discontinues and the data will not be submitted to regulatory authorities. There is no end date for eligibility to submit a data sharing request for this study.
Access criteria: Qualified researchers may submit a request containing the research objectives, the Amgen product(s) and Amgen study/studies in scope, endpoints/outcomes of interest, statistical analysis plan, data requirements, publication plan, and qualifications of the researcher(s). In general, Amgen does not grant external requests for individual patient data for the purpose of re-evaluating safety and efficacy issues already addressed in the product labelling. Requests are reviewed by a committee of internal advisors. If not approved, a Data Sharing Independent Review Panel will arbitrate and make the final decision. Upon approval, information necessary to address the research question will be provided under the terms of a data sharing agreement. This may include anonymized individual patient data and/or available supporting documents, containing fragments of analysis code where provided in analysis specifications. Further details are available at the URL below.
Data sharing details ↗ · www.amgen.com
Ran from Feb 2018 to primary completion in Jul 2022, 52 months.
Results were first posted in Jul 2023, 1 year after primary completion.
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Studies of the drug tested here: Glycerol phenylbutyrate
Urea Cycle Disorders, Inborn →