Study to Evaluate the Safety and Efficacy of Pegvaliase in Adolescents (Ages 12-17) With Phenylketonuria (PEGASUS)
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ClinicalTrials.gov Identifier: NCT05270837 |
Recruitment Status :
Active, not recruiting
First Posted : March 8, 2022
Last Update Posted : September 28, 2023
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Phenylketonuria (PKU) | Drug: Pegvaliase Other: Diet Only | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 55 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase 3 Multi-Center Study to Evaluate the Safety and Efficacy of Subcutaneous Injections of Pegvaliase in Adolescent Subjects (Ages 12-17) With Phenylketonuria Featuring an Open-Label Randomized Two-Arm (Active vs Diet-Only Control) Design |
Actual Study Start Date : | June 17, 2022 |
Estimated Primary Completion Date : | December 2025 |
Estimated Study Completion Date : | December 2025 |

Arm | Intervention/treatment |
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Experimental: Pegvaliase |
Drug: Pegvaliase
Pegvaliase 2.5mg/10mg/20mg/40mg/60mg self-administered from 1 time up to 7 times a week
Other Names:
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Drug: Diet Only
Participants will be managing their PKU with diet alone. Participants in the diet-only control arm will be required to maintain and adjust dietary and medical protein food intake through Week 72, initiating pegvaliase treatment beginning Week 73 and, from Weeks 73 through 145.
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Other: Diet Only
Diet Control |
- Change in blood Phe concentration [ Time Frame: Treatment naïve baseline following 72 weeks on study ]
- Incidence of treatment-emergent adverse events as assessed by CTCAE v5.0 [ Time Frame: Treatment naïve baseline following 72 weeks on study ]
- Change in total dietary protein intake [ Time Frame: Treatment naïve baseline following 72 weeks on study ]
- Characterize area under plasma concentration time curve (AUC) of pegvaliase [ Time Frame: Baseline to 153 weeks ]
- Characterize maximum plasma concentration (Cmax) of pegvaliase [ Time Frame: Baseline to 153 weeks ]
- Characterize trough plasma concentration (Ctrough) of pegvaliase [ Time Frame: Baseline to 153 weeks ]
- Characterize time to reach maximum plasma concentration (Tmax) of pegvaliase [ Time Frame: Baseline to 153 weeks ]

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Ages Eligible for Study: | 12 Years to 17 Years (Child) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria
- Is 12 to 17 years old (US), inclusive, or 12 to 15 years (EU), inclusive, at the start of the Screening/Run-in Period (Day -28).
- Diagnosis of PKU and failure to maintain recommended blood Phe levels on existing management (sapropterin dihydrochloride and Phe-restricted diet) demonstrated by 2 blood Phe concentration measurements > 600 μmol/L during the Screening/Run-in Period (7 to 10 days in between blood Phe assessments) and average blood Phe concentration > 600 μmol/L over the past 12 months (per available data).
- Willing and able to maintain and adjust dietary and medical protein food intake according to the study protocol under the supervision of a study dietician or adequately trained designee per investigator discretion during study participation.
- If on medication for ADHD, depression, or other psychiatric disorder, stable dose of medication for ≥ 8 weeks prior to enrollment and willing to maintain stable dose unless a change is medically indicated.
- An adult (≥ 18 years of age) has been identified who is willing and competent to observe the participant during study drug administration and for a minimum of 1 hour following administration.
- Participants must be capable of giving signed informed consent
- If sexually active, male or female participants must not plan to become pregnant (self or partner) and must use 2 acceptable methods of contraception while participating in the study beginning at Screening and for 4 weeks after discontinuing study drug.
Exclusion Criteria
- Previous treatment with pegvaliase.
- Use of any medication that is intended to treat PKU, including the use of large neutral amino acids, within 14 days prior to the administration of study drug on Day 1.
- Use or planned use of any injectable drugs containing polyethylene glycol (PEG; other than pegvaliase), including medroxyprogesterone injection, within 3 months prior to the start of Screening/Run-in and during study participation with the exception of COVID-19 vaccinations.
- A history of organ transplantation or on chronic immunosuppressive therapy.
- Use of any investigational product or investigational medical device within 30 days prior to Screening/Run-in or requirement for any investigational agent prior to completion of all scheduled study assessments.
- A positive test for HIV antibody, hepatitis B surface antigen, or hepatitis C antibody.
- Alanine aminotransferase (ALT) concentration > 2 × the upper limit of normal (ULN).
- Creatinine > 1.5 × ULN.
- Inability to identify and/or communicate to others that the participant is experiencing symptoms of potential anaphylaxis due to cognitive impairment or other reasons.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05270837

Study Chair: | Study Director | BioMarin Pharmaceutical |
Responsible Party: | BioMarin Pharmaceutical |
ClinicalTrials.gov Identifier: | NCT05270837 |
Other Study ID Numbers: |
165-306 |
First Posted: | March 8, 2022 Key Record Dates |
Last Update Posted: | September 28, 2023 |
Last Verified: | September 2023 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
PKU BioMarin Phenylketonuria BMN165 |
PAL Subcutaneous Injections Pegvaliase adolescent PKU |
Phenylketonurias Brain Diseases, Metabolic, Inborn Brain Diseases, Metabolic Brain Diseases Central Nervous System Diseases |
Nervous System Diseases Amino Acid Metabolism, Inborn Errors Metabolism, Inborn Errors Genetic Diseases, Inborn Metabolic Diseases |