Hemolytic disease of the fetus and newborn is a rare autoantibody condition for which there is no approved therapy. It causes the mother’s immune system to attack and breakdown the red blood cells in her fetus or newborn. It is one of more than 10 immunological and neurological indications for which Johnson & Johnson is developing its experimental monoclonal antibody nipocalimab. We spoke to Katie Abouzahr, vice president of the autoantibody portfolio and maternal fetal disease area leader for Johnson and Johnson, about hemolytic disease of the fetus and newborn, the challenges of developing a therapy for a rare condition in pregnant women, and why nipocalimab has the potential to be a pipeline in a product.