Clinical trial Phase 1/2 Interventional Ages 18 and up

A Gene Therapy Study of BMN 331 in Subjects With Hereditary Angioedema

Run by BioMarin Pharmaceutical · NCT05121376 · Data updated 2026-11-12

Fully enrolled, still running. This study is not taking new participants. Its registered completion date is 2028-11.

This is a Phase 1/2, single-arm, open-label, dose-escalation and dose-expansion study of BMN 331 for the treatment of hereditary angioedema (HAE) due to C1 Esterase Inhibitor (C1-INH) protein deficiency. The study drug BMN 331is identified as AAV5 hSERPING1, an adeno-associated virus (AAV5)-based gene therapy vector that expresses wild-type human C1 Esterase Inhibitor (hC1-INH), under the control of a liver-selective promoter, and is being developed for the treatment of HAE with C1-INH deficiency. The pharmaceutical form of BMN 331 is a solution for intravenous infusion.

Quick facts

PhasePhase 1/2
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment44 (estimated)
SponsorBioMarin Pharmaceutical
Industry-sponsored
Drugs / interventionsDose 1 of BMN 331, Dose 2 of BMN 331, Dose 3 of BMN 331, Dose 4 of BMN 331, Dose 5 of BMN 331, Dose 6 of BMN 331, Dose 7 of BMN 331
Locations16 sites (Australia, Spain, United States)
Trial IDNCT05121376 on ClinicalTrials.gov

What this trial studies

BMN 331 is an investigational, single administration gene therapy intended to modify the disease course of HAE. Preclinical studies have shown that BMN 331 can transduce hepatocytes resulting in restoration of the deficient circulating levels of hC1-INH that cause HAE. Study 331-201 is a two-part (part A and part B), first-in-human, Phase 1/2 study designed to assess the safety and efficacy of BMN 331 in patients with HAE. Subjects will be followed for 5 years following BMN 331 infusion. Part A of the study is a dose escalation phase designed to assess the preliminary safety of a single IV administration of BMN 331 and to determine whether there is a dose-dependent increase in C1-INH protein expression following administration of BMN 331. Part B is a dose expansion phase designed to demonstrate that up to three safe doses of BMN 331 (as determined in Part A) sustains a clinically meaningful increase in C1-INH levels.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Female or male adults ( ≥ 18 years old)
2. Part A only: Confirmed diagnosis of Type I HAE due to C1-INH deficiency confirmed by genotyping of the SERPING1 gene Part B only: Confirmed diagnosis of Type I or II HAE due to C1-INH deficiency confirmed by genotyping of the SERPING1 gene
3. Currently using an HAE medication regimen that consists of a routine long-term prophylactic treatment for at least 6 months prior to enrollment or an on-demand therapy regimen for a documented attack frequency of at least 4 attacks within the last 12 months prior to enrollment or at least 2 attacks within the last 6 months prior to enrollment
4. Trained in self-administering acute attack treatment and is able to adequately manage acute attacks in a home setting
5. Willingness to abstain from consumption of alcohol for at least 52 weeks post BMN 331 infusion and to use highly effective contraception

Exclusion Criteria:

1. Evidence of active or chronic infection, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or any immunosuppressive disorder
2. Contraindication to using glucocorticosteroids GCS, including a diagnosis of glaucoma or untreated osteoporosis
3. Active malignancy (except non-melanoma skin cancer) autoimmune, metabolic (i.e., diabetes), hematologic, cardiac, or renal disease that is of clinical significance defined as requiring regular medical attention and treatment
4. Prior gene therapy treatment
5. Prior use of high-dose attenuated androgens in the last 1 year prior to the study
6. History or current clinically relevant liver disease (eg, nonalcoholic steatohepatitis \[NASH\], or chronic viral hepatitis B or C \[HBV or HCV\] or autoimmune hepatitis)
7. Have a history or are at risk for clinically significant thromboembolic events (TEE) , or known underlying risk factor for thrombosis including thrombotic microangiopathy (TMA)

Where it's running

  • AllerVie Clinical Research
    Birmingham, Alabama, United States
  • Medical Research of Arizona
    Scottsdale, Arizona, United States
  • University of California San Diego
    San Diego, California, United States
  • Asthma & Allergy Associates P.C.
    Colorado Springs, Colorado, United States
  • Dr. Henry J. Kanarek Allergy, Asthma & Immunology
    Overland Park, Kansas, United States
  • Institute For Asthma & Allergy
    Chevy Chase, Maryland, United States
Show 10 more locations
  • Mississippi Center for Advanced Medicine
    Madison, Mississippi, United States
  • Washington University School of Medicine
    St Louis, Missouri, United States
  • Duke Health
    Durham, North Carolina, United States
  • University of Cincinnati (UC) Physicians Company, LLC
    Cincinnati, Ohio, United States
  • Optimed Research, LTD
    Columbus, Ohio, United States
  • The Pennsylvania State University (Penn State) Milton S. Hershey Medical Center
    Hershey, Pennsylvania, United States
  • AARA Research Center
    Dallas, Texas, United States
  • Royal Prince Alfred Hospital,
    Camperdown, Australia
  • Hospital Universitario Vall d'Hebron
    Barcelona, Spain
  • Hospital Universitario La Paz
    Madrid, Spain

Study contacts

  • Principal investigator: MD Medical Director — BioMarin Pharmaceutical

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-15 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.