Rallybio Corporation announced the prioritization of its portfolio and a 45% workforce reduction to focus resources on its Phase 2-ready clinical stage programs, RLYB212 and RLYB116. RLYB212 is a novel human monoclonal anti-HPA-1a antibody in development for the prevention of fetal and neonatal alloimmune thrombocytopenia (FNAIT), and RLYB116 is a once-weekly, low volume subcutaneously injected inhibitor of complement component 5 (C5) in development for patients with complement-mediated diseases. With these changes, Rallybio expects to extend its cash runway into mid-2026.

RLYB212 - The Company plans to provide an update on Phase 2 discussions for RLYB212 with the European Medicines Agency (EMA) in the first half of 2024. Rallybio continues to expect to initiate a Phase 2 dose confirmation study for RLYB212 in pregnant women at higher risk of FNAIT in the second half of 2024. The Company continues to screen mothers in the FNAIT natural history alloimmunization study, a non-interventional study designed to provide a contemporary dataset for HPA-1a alloimmunization frequency in a racially and ethnically diverse population.

Rallybio expects to provide an update on screening numbers in its full-year earnings release in March 2024. RLYB116 - Manufacturing work announced in December 2023 is progressing, and Rallybio is encouraged by data indicating the potential to achieve improved tolerability at higher doses of RLYB116. While the exposure levels of RLYB116 demonstrated in the Phase 1 study are expected to be suitable for the treatment of patients with generalized myasthenia gravis, the Company believes the ongoing enhancements will enable higher exposure to RLYB116, supporting the treatment of patients with a broader range of complement-mediated diseases, including paroxysmal nocturnal hemoglobinuria and antiphospholipid syndrome.

Rallybio continues to expect to complete this manufacturing work and provide an update on the development plan for RLYB116 in the second half of 2024.