Two New Rare Disease Drug Programs Announced

According to a story from, the biopharmaceutical company Rallybio has announced two development programs for therapeutics intended to treat rare diseases. The two programs consist of RLBY212, which is in development as a treatment for fetal/neonatal alloimmune thrombocytopenia (FNAIT), and RLBY116, which is in development as a treatment for rare diseases affecting complement regulation. Rallybio is focused on developing life-changing treatments for patients living with severe and rare disorders. 

About Fetal/Neonatal Alloimmune Thrombocytopenia (FNAIT)

Thrombocytopenia is a condition of low levels of platelets in the blood. In FNAIT, the platelet level in the fetus is brought down as a result of attacks from the immune system of the mother. The lowered platelet count increases risks of bleeding, including bleeding in the brain, which can cause major long-term impacts. FNAIT is linked to the appearance of antibodies from the mother’s immune system that are tuned to target antigens inherited from the father. In mild cases, no symptoms are present, but in more serious FNAIT symptoms include bleeding, more specifically intracranial hemorrhage or neurologic sequelae. Death occurs in around ten percent of babies with intracranial hemorrhage. Treatments include IVIG and platelet transfusions. To learn more about FNAIT, click here.

About The Programs

RLBY212 is designed as an anti-HPA-1a monoclonal antibody that is delivered subcutaneously. For FNAIT, this treatment would be administered to mothers deemed at risk and is intended to eliminate fetal platelets from the bloodstream of the mother, therefore preventing alloimmunization and the risk of FNAIT. This treatment could help reduce incidences of FNAIT, which is currently estimated to impact anywhere from 1 in 800 to 1 in 5,000 births. 

RLBY116 is classified as an antibody mimetic that is meant to inhibit C5 rapidly, sustainably, and completely. It is also considered suitable for administration subcutaneously. There are a significant number of rare diseases that have been linked to the dysregulation of the complement system, meaning that several diseases could be treated effectively with RLBY116. 

These two development pipelines could help make the difference for patients living with these uncommon and challenging diseases.

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