A Phase 2, Multicenter, Open-label Study to Evaluate the Pharmacokinetics and Safety of RLYB212 in Pregnant Women at Higher Risk for HPA-1a Alloimmunization (RLYB212)

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare and potentially dangerous disorder that can cause severe bleeding in the unborn and newborn baby. An unborn or newborn baby with a low platelet count can have severe bleeding problems which can in rare cases lead to brain damage or death. Currently, there are no treatments to prevent this condition in pregnant women at risk.The purpose of this research study, called IPA2202, is to see if RLYB212 is safe and how the body processes and responds to it among pregnant women at higher risk for HPA-1a alloimmunisation.The study is comprised of three phases: • A two-part screening phase (Screening Part 1 and Screening Part 2)• An treatment phase during pregnancy• An after delivery follow-up phase. Participants who are not eligible to receive the study drug or decide not to participate, may be invited to enter a research study where they will be observed throughout their pregnancy.The total study duration for you is approximately 44 weeks. Participants may undergo the following procedures: Physical examination, vital signs (blood pressures, heart rate, and body temperature), electrocardiogram (to check the heart), ultrasound scan, blood and urine samples and subcutaneous injection (under your skin) of study drug.Approximately 5000 pregnant women globally will be screened to identify 8 higher risk pregnancies for this study. Rallybio IPA, LLC is the Sponsor for this study and is based in the United States.