Phase II of a clinical trial investigating Rallybio’s experimental therapy RLY212 in pregnant patients at risk of fetal and neonatal alloimmune thrombocytopenia (FNAIT) has recently begun, according to a recently published press release.
The trial aims to determine the optimal dosage of the drug by determining how the body metabolizes and excretes it (pharmacokinetics) during pregnancy. Furthermore, the trial seeks to analyze fetal and neonatal outcomes and whether the drug effectively prevents HPA-a1 alloimmunization.
“FNAIT can arise during pregnancy due to an immune incompatibility between an expectant mother and her fetus in a specific platelet antigen called human platelet antigen 1, or HPA-1,” the authors wrote.
There is growing interest in the use of monoclonal antibodies to prevent alloimmunization and FNAIT. RLYB212 is a monoclonal antibody that targets the human platelet antigen (HPA) -1a to prevent the immunization and the binding of maternal antiplatelet antibodies to fetal platelets.
Researchers will recruit patients in several European countries. The study will consist of three phases: first, a screening phase using a laboratory testing paradigm to detect women at risk of FNAIT, a prenatal phase, and postpartum follow-up phase.
The study’s primary outcome measures are detecting any adverse effects related to the treatment and measuring RLYB212 levels in maternal serum. Secondary outcome measures included neonatal RLYB212 levels (measured via the umbilical cord), frequency of neonatal thrombocytopenia, and measurement of anti-RLYB212 antibodies.
