Nipocalimab Shows Promise in Treatment of HDFN

For decades, there have been no new advancements in doctors’ ability to treat hemolytic disease of the fetus and newborn, or HDFN. The condition, in which a pregnant patient has antibodies that attack fetal red blood cells in utero, typically causes fetal anemia and requires blood transfusion. A new drug aims to change this.

Nipocalimab is designed to lower the pregnant patient’s antibodies and stop them from crossing the placenta so they can’t attack the fetus’s red blood cells. The Colorado Fetal Care Center at Children’s Hospital Colorado is one of a small number of participating centers worldwide testing the drug’s efficacy and safety as part of a phase 3 randomized trial sponsored by Johnson and Johnson.

Though the condition is relatively rare, its impacts can be devastating. The blood transfusions carry a roughly 1% fetal loss rate each time they are performed and can increase the risk of early labor or emergent delivery. The goal of nipocalimab is to delay, limit or eliminate the need for transfusions.

The project, also known as the Azalea study, will last three years in total, and is enrolling patients who have a history of HDFN, are over 18 and have tested positive for the concerning red cell antibodies. Participants receive a weekly dose of nipocalimab between 13 and 35 weeks’ gestation. From there, the plan is to follow babies for the first two years of their life to ensure the long-term safety of the drug.

“The interesting thing about this disease is that even if a baby gets successfully transfused, after delivery their blood volume may drop again, because the antibodies remain there for quite some time,” explains maternal fetal medicine specialist Michael Zaretsky, MD. Additionally, because the drug lowers antibodies, babies may experience a higher risk for certain infections.

If the study proves nipocalimab safe and effective, it will mark a monumental moment in HDFN treatment.

“The history of the disease is pretty profound. I mean, they were doing the first fetal transfusion in the 1960s without the use of ultrasound, and it wasn’t until the early 1980s when the first ultrasound-guided needle procedure was done on the umbilical cord,” he says. “It’s been really the same procedure over the last 40 years. And if this actually works, it will be another huge step in the evolution of HDFN treatment that will further prevent both morbidity and mortality.”