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Rallybio Announces Publication of Data Highlighting the Ability of HPA-1a-Specific Antibodies to Prevent Alloimmunization in an Authentic Mouse Model of FNAIT
-- Data Demonstrates that HPA-1a Alloimmunization can be Prevented with Prophylactic Administration of Low Levels of HPA-1a-specific Antibodies -- NEW HAVEN,
About this update from Rallybio Corporation
[{"type":"text","content":"\n-- Data Demonstrates that HPA-1a Alloimmunization can be Prevented with Prophylactic Administration of Low Levels of HPA-1a-specific Antibodies --\n\n NEW HAVEN, Conn.--(BUSINESS WIRE)--\nRallybio Corporation (Nasdaq: RLYB) today announced publication of preclinical study results for two human HPA-1a-specific antibodies in development for the prevention of FNAIT. The results demonstrate that low doses of the two HPA-1a-specific antibodies, the polyclonal candidate RLYB211 and the monoclonal candidate RLYB212, are equally effective at rapidly clearing HPA-1a-positive platelets from circulation and preventing alloimmunization to HPA-1a. As expected, prophylactically blocking HPA-1a alloimmunization prevented the onset of FNAIT. These results also establish the concentration-effect relationship and threshold exposure targets for effective prophylactic treatment with HPA-1a specific antibodies to prevent FNAIT. The findings were published in the journal Blood, the official journal of the American Society of Hematology.\n\nFNAIT is a rare, life-threatening bleeding disorder where maternal alloantibodies cross the placenta and lead to depletion of fetal platelets. There are no currently approved therapies for the prevention of FNAIT. In this study, a novel alloantigen-specific mouse model developed by the senior author Dr. Peter J. Newman, Blood Research Institute at the Versiti Blood Center of Wisconsin, was used to examine the efficacy of prophylactic treatment regimens of RLYB211 and RLYB212, Rallybio’s two therapeutic candidates for the prevention of FNAIT.\n\nResults showed:\n\n\nBoth RLYB211 and RLYB212 were equally effective at driving rapid and complete elimination of HPA-1a positive platelets from circulation and preventing the development of HPA-1a alloantibodies.\n\n\nHPA-1a negative female mice that were treated prophylactically with anti-HPA-1a antibody prior to exposure to HPA-1a positive platelets gave birth to HPA-1ab pups with significantly improved platelet counts and no bleeding symptoms.\n\n\nThe threshold effect for rapid and complete elimination of HPA-1a positive platelets is achieved at circulating anti-HPA-1a antibody concentrations estimated to bind as little as ~10% of antigen, consistent with the clinical prophylactic treatment paradigm established for anti-Rhesus D (anti-RhD) to prevent Hemolytic Disease...