Janssen Reports Positive Phase 2 Results for Nipocalimab in Pregnant Women at High Risk for Severe Hemolytic Disease of the Fetus and Newborn

Rare Daily Staff

The Janssen Pharmaceutical Companies of Johnson & Johnson reported positive topline results from the proof-of-concept phase 2 open-label UNITY clinical trial for the treatment of pregnant adults at high risk for severe hemolytic disease of the fetus and newborn.

Hemolytic disease of the fetus and newborn (HDFN) is a serious and rare condition that can cause life-threatening anemia in the fetus. It occurs when the blood types of a pregnant individual and their fetus are incompatible. The trial met the primary endpoint, with the majority of pregnant patients who received nipocalimab achieving a live birth at or after the gestational age of 32 weeks, without the need for an intrauterine transfusion throughout their entire pregnancy. During the treatment period of approximately 20 weeks, nipocalimab demonstrated a safety profile that supports further development of the treatment in HDFN.

Nipocalimab was granted Fast Track designation in July 2019 and orphan drug status in June 2020 by the U.S. Food and Drug Administration, and orphan medicinal product designation by the European Medicines Agency in October 2019 for HDFN.

“These early results represent an important step towards delivering a potential medication for expectant mothers at high risk of severe HDFN, and we are encouraged by what this treatment could mean for families affected by this potentially devastating disease,” said Katie Abouzahr, vice president, Autoantibody Portfolio Development Leader, Janssen Research & Development. “We look forward to sharing the full phase 2 results of the UNITY trial at an upcoming scientific medical meeting while we continue to plan for a pivotal phase 3 trial.”

UNITY is a global, multicenter, open-label, non-blinded phase 2 clinical trial to evaluate the safety and efficacy of nipocalimab for the treatment of pregnant adults at high risk for severe HDFN. In the trial, 14 participants received once weekly intravenous infusions. The primary endpoint was live birth at or after gestational age of 32 weeks, without a need for an intrauterine transfusion throughout the entire pregnancy. Adverse events were monitored up to approximately 24 weeks post-delivery for parents and up to approximately 96 weeks post-birth for children.

HDFN is a rare autoantibody-driven disease where antibodies produced in a pregnant person’s immune system cross the placenta and attack fetal red blood cells—causing fetal hemolysis leading to anemia. The severe form of HDFN, which is categorized as an ultra-rare disease, can lead to life-threatening anemia. Today, there are no approved therapeutics for the treatment of HDFN, and pregnancies affected by severe HDFN may necessitate repeated intrauterine transfusions—invasive, technically complex surgical procedures performed by specialists that may be associated with an increased rate of fetal mortality and premature birth. According to the American Journal of Obstetrics and Gynecology, in the United States, it is estimated that up to 80 out of every 100,000 pregnancies are affected by HDFN each year.

Nipocalimab is an investigational, high affinity, fully human, aglycosylated, effectorless, monoclonal antibody that is believed to selectively block the Fc receptor (FcRn) to reduce levels of circulating immunoglobulin G (IgG) antibodies, including autoantibodies and alloantibodies that underlie multiple conditions.

Photo: Katie Abouzahr, vice president, Autoantibody Portfolio Development Leader, Janssen Research & Development