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Open Access
CC BY 4.0 · Am J Perinatol
DOI: 10.1055/a-2753-9323
Original Article

Design of a Phase 3, Multicenter, Randomized, Open-label Study of Nipocalimab or IVIG and Prednisone in Pregnancies at Risk for Fetal and Neonatal Alloimmune Thrombocytopenia

Authors

  • James B Bussel

    1   Department of Pediatrics, Division of Hematology/Oncology, Weill Cornell Medical College, New York, United States (Ringgold ID: RIN12295)
    2   New York Presbyterian Hospital, New York, United States

  • Barbara Stegmann

    3   Johnson & Johnson, Spring House, United States

  • Pamela Baker

    3   Johnson & Johnson, Spring House, United States

  • Abbie Oey

    3   Johnson & Johnson, Spring House, United States

  • Yanxin Jiang

    3   Johnson & Johnson, Spring House, United States

  • Rebecca Zaha

    3   Johnson & Johnson, Spring House, United States

  • Hillary Van Valkenburgh

    3   Johnson & Johnson, Spring House, United States

  • Babajide Keshinro

    4   Johnson & Johnson Biologics BV, Leiden, Netherlands

Supported by: This study is sponsored by Johnson & Johnson

Clinical Trial:

Registration number (trial ID): NCT06533098, Trial registry: ClinicalTrials.gov (http://www.clinicaltrials.gov/), Type of Study: Multicenter, randomized, open-label, phase 3 study


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Objective: Nipocalimab, a neonatal Fc receptor blocker, showed evidence of efficacy and safety in preventing or delaying fetal anemia in a phase 2 study of early-onset severe hemolytic disease of the fetus and newborn, demonstrating potential for treatment of other maternal immunoglobulin G alloantibody–mediated fetal diseases. The phase 3 FREESIA-3 study aims to evaluate the efficacy and safety of nipocalimab or intravenous immunoglobulin (IVIG) with prednisone in pregnancies with a previous occurrence of fetal and neonatal alloimmune thrombocytopenia (FNAIT) with or without intracranial hemorrhage or severe fetal/neonatal bleeding (high-risk or standard-risk, respectively). Study Design: FREESIA-3 is a phase 3, open-label, randomized, multicenter study in pregnant individuals at risk for FNAIT. Participants are randomized 4:1 to receive either weekly 45 mg/kg intravenous nipocalimab or weekly IVIG with prednisone starting at 13-18 weeks gestational age (standard-risk) or 12 weeks gestational age (high-risk) until delivery. During treatment, pregnant participants will receive ultrasound monitoring every 2 weeks for fetal bleeding, growth, and development. Postnatal follow up is 24 weeks for maternal participants and 104 weeks for neonates/infants. Results: The primary endpoint is an adverse outcome of death or adjudicated severe bleeding in utero up to 1 week post-birth, or platelet count at birth of <30 × 10<sup>9</sup>/L in a fetus/neonate. Secondary endpoints include fetal/neonatal death, neonatal platelet count at birth, nadir neonatal platelet count over 1 week post-birth, neonate requiring platelet transfusion(s), adjudicated fetal and neonatal bleeding up to 1 week post-birth, neonate receiving IVIG for thrombocytopenia, safety in maternal participants and neonates/infants, and immunogenicity of nipocalimab. Exploratory endpoints include patient- and caregiver-reported outcome assessments and nipocalimab pharmacokinetics and pharmacodynamics. <b>Conclusion:</b> FREESIA-3, an open-label, multicenter, randomized, phase 3 study, will evaluate the efficacy and safety of nipocalimab in both standard-risk and high-risk pregnancies for FNAIT.



Publication History

Received: 30 October 2025

Accepted: 09 November 2025

Accepted Manuscript online:
25 November 2025

© . The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).

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