News|Articles|October 1, 2026

PETUNIA Study to Track Nipocalimab Use in Pregnancy

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Key Takeaways

FcRn blockade with nipocalimab necessitates pregnancy surveillance because placental FcRn drives maternal–fetal IgG transfer, raising theoretical concerns about altered passive immunity in exposed offspring.
PETUNIA captures prospective and retrospective exposures via a global safety database from first approval through 2036, requiring dosing within two weeks preconception or any time during gestation.
Four targeted follow-up questionnaires assess pregnancy outcome, neonatal status, and infant outcomes at 3 and 12 months, excluding clinical-trial exposures and non-identifiable reports.
Primary endpoints include hypertensive disorders, fetal growth restriction/SGA, placental abruption, serious neonatal/infant infections, and non-chromosomal major congenital malformations with exact 95% confidence intervals.
Enrollment targets ≥162 pregnancies (≥50 prospective with known outcomes) over ~10 years, benchmarking rates against gMG and general obstetric populations while analyzing retrospective cases separately for selection bias.

PETUNIA, a new global pharmacovigilance study, will track pregnancy, maternal, and infant outcomes among patients with gMG exposed to nipocalimab.

Johnson & Johnson presented the design of PETUNIA (Pregnancy Enhanced Tracking with Neonatal and Infant Assessment), a global pharmacovigilance study that will track pregnancy, maternal, and infant outcomes in individuals with generalized myasthenia gravis (gMG) exposed to nipocalimab immediately before or during pregnancy. The trial-in-progress poster was presented at the 2026 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Annual Meeting and MGFA Scientific Session in Orlando, Florida.¹

Why a dedicated pregnancy safety study

gMG is a rare autoantibody-mediated disease that frequently affects individuals of childbearing potential. Nipocalimab, an FcRn blocker approved for gMG, works by blocking the neonatal Fc receptor, which normally maintains circulating levels of immunoglobulin G (IgG), including the pathogenic IgG antibodies that drive gMG, and extends IgG's half-life; the safety and efficacy of nipocalimab have not been studied in pregnant individuals with gMG or their offspring. Because FcRn is also expressed on placental syncytiotrophoblasts and mediates maternal-fetal IgG transfer, the investigators said pregnancy surveillance is important to characterize the drug's potential effects on immunity in offspring.

The investigators noted that single-product prospective pregnancy registries, the traditional tool for this kind of postmarketing safety data, often face recruitment and retention challenges and can fail to deliver timely, data-driven evidence, particularly for a rare disease like gMG. PETUNIA instead uses an enhanced pharmacovigilance approach that pairs routine reporting of pregnancy exposure with structured, targeted follow-up questionnaires (TFUQs) and rigorous data entry and quality-control processes, which the investigators said is intended to overcome those limitations.

PETUNIA Study design

PETUNIA is a global, non-interventional, single-arm study that will capture prospective and retrospective reports of nipocalimab exposure immediately before or during pregnancy through Johnson & Johnson's global safety database, tracking cases from the time of nipocalimab's first approval through 2036. Eligible cases must have documented exposure to at least 1 dose of nipocalimab either immediately prior to pregnancy, within 2 weeks before the estimated date of conception, or at any point during pregnancy.

Reports are followed using 4 structured TFUQs: a baseline questionnaire, a pregnancy-outcome questionnaire, a neonatal and early infant outcomes questionnaire administered at 3 months, and an infant outcomes questionnaire at 12 months, with corresponding live births assessed through the first year of life. Cases are excluded if nipocalimab was discontinued more than 2 weeks before conception, if a report cannot be traced to an identifiable pregnant individual or health care provider, if there is insufficient contact information for follow-up, if exposure occurred in an interventional clinical trial setting, or if the only reported exposure was paternal.

Endpoints and planned analysis

Primary endpoints include the prevalence of maternal complications and fetal or neonatal outcomes, specifically fetal growth restriction, hypertensive disorders of pregnancy (including preeclampsia, gestational hypertension, HELLP syndrome, and eclampsia), placental abruption, and small for gestational age, alongside serious infections in the neonate (within 27 days of birth) and infant (through the first year of life) and non-chromosomal major congenital malformations. Secondary endpoints include live birth, spontaneous abortion, stillbirth, preterm birth, intrapartum and postpartum hemorrhage, and fetal, neonatal, and infant death.

The projected sample size is at least 162 total pregnancies, including 50 prospectively reported cases with known outcomes, expected to accrue over a 10-year period across regions where nipocalimab is approved and prescribed. Analyses will be stratified by whether a pregnancy was reported prospectively or retrospectively, with prospectively reported cases serving as the primary analysis and retrospective reports analyzed separately to help minimize selection bias; proportions for each endpoint will be calculated with 95% confidence intervals using exact methods and contextualized against outcomes in the broader gMG population and the general population of pregnant individuals.

“This descriptive safety study will generate prevalence estimates of pregnancy, maternal, and infant outcomes after maternal exposure to nipocalimab immediately before or during pregnancy,” Neelam Goyal, MD, FAAN, clinical professor of neurology and neurological sciences in the division of neuromuscular medicine at Stanford University School of Medicine, and colleagues, wrote. As of the AANEM presentation, PETUNIA's ClinicalTrials.gov registration remained in progress, with no NCT number yet assigned.

Nipocalimab's approval history

The FDA approved nipocalimab (Imaavy) in April 2025 for gMG in adults and adolescents 12 years and older who are anti-AChR or anti-MuSK antibody positive, making it the first FcRn blocker approved for pediatric patients with the disease; it is dosed as a 30-mg/kg intravenous loading dose followed by 15 mg/kg every 2 weeks.²

The approval was based on the phase 3 Vivacity-MG3 trial, in which nipocalimab plus standard of care improved MG-ADL score by 4.68 points over 24 weeks compared with 3.25 points with placebo plus standard of care (P =.003), alongside sustained autoantibody reduction of up to 75%; serious adverse events occurred less often with nipocalimab than placebo (9% vs 14%).³

The European Commission approved nipocalimab for gMG in adults and adolescents 12 years and older in December 2025, following a positive opinion from the European Medicines Agency. Most recently, the FDA approved nipocalimab in August 2026 for warm autoimmune hemolytic anemia in patients 12 years and older previously or currently treated with corticosteroids, the first approved treatment specifically for that condition; in the pivotal trial supporting that approval, 3 times as many patients achieved a durable hemoglobin response with nipocalimab as with placebo by week 24.^4,5

Click here for more AANEM 2026 coverage.