Rapid drug desensitization for adults with hypersensitivity to Palynziq

A Phase 4 Study to Evaluate the Impact of a Rapid Drug Desensitization (RDD) Protocol for Adults with Phenylketonuria and Experiencing Hypersensitivity Reactions to Palynziq

Phase 4 Interventional BioMarin Pharmaceutical · NCT06780332

This study is testing a quick method to help adults with phenylketonuria who are allergic to Palynziq tolerate the medication better so they can continue their treatment.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment10 (estimated)
Ages18 Years and up
SexAll
SponsorBioMarin Pharmaceutical Industry-sponsored
Locations1 site (Chevy Chase, Maryland)
Trial IDNCT06780332 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate the effectiveness of rapid drug desensitization (RDD) in improving tolerability and treatment persistence for adult patients with phenylketonuria (PKU) who have experienced hypersensitivity reactions to Palynziq. Participants will undergo a one-day RDD procedure followed by a 24-week monitoring period to assess their response to the medication. The study includes screening, in-clinic dosing, and remote follow-up visits to track any hypersensitivity reactions and changes in dosing. The total duration of participation is approximately 30 weeks.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with phenylketonuria who have experienced significant hypersensitivity reactions to Palynziq.

Not a fit: Patients who have not experienced hypersensitivity reactions to Palynziq or are under 18 years old may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could enable patients to continue using Palynziq effectively, improving their treatment outcomes.

How similar studies have performed: While rapid drug desensitization has been explored in other contexts, this specific application for Palynziq in PKU patients is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age:

  1.Participants must be 18 years of age or older inclusive, at the time of signing the informed consent.
* Type of Participant and Disease Characteristics 2. Participants must have phenylketonuria and must have been receiving commercial Palynziq and enrolled in the REMS.

  3. Participants must have developed HSRs leading to treatment interruption or reduction of dose or dosing frequency (Graade 2 or above) while on Palynziq, and must be able to undergo RDD within 6weeks from the reactive HSR and last Palynziq dose.
* Sex and Contraceptive/Barrier Requirement 4. Males and females are eligible to participate in this clinical study. Contraceptive use is not required during the study. Please refer to the Pregnancy section of USPI for further information.
* Informed Consent 5. Participants must be capable of giving written informed consent as described in Section 10.1, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.

Exclusion Criteria:

* Medical Conditions:

  1. Participant may not have any kind of disorders that, in the opinion of the investigator, may compromise the ability of the participant to give written informed consent and/or comply with any aspect of the study, and/or where any aspect of participation would be medically inadvisable for the underlying disorder.
  2. Participant must not be pregnant on the day of the RDD.
  3. Participants with uncontrolled asthma, active upper repiratory infection or other active infections, or cardiovascular disease. Asthma control will be assessed using the Asthma Control Test at screening.
* Prior/Concomitant Therapies:

  4. Participants were not using antihistamine premedication(s) at the time of reactive HSRs.

  5. Participants are willing and able to resume and tolerate Palynziq at the reactive dose prior to the RDD.

  6. Participant must not be receiving concurrent injectables containing PEG with the exception of PEG-containing vaccines, such as COVID-19 vaccinations (see Section 6.7).

  7.Participants receiving beta blockers.
* Prior/Concurrent Clinical Study Experience 8. Participants may not be currently participating in an interventional study of any investigational product, device, or procedure, or any other BioMarin clinical trial or post-marketing study.

Other Exclusions 9. Participants must not be experiencing reactions that are not appropriate for RDD, including severe cutaneous adverse reactions (SCAR) as defined by the American Academy for Allergy, Asthma, and Immunology.

Where this trial is running

Chevy Chase, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PhenylketonuriaPKUPalynziqpegvaliase
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.