Rallybio Corp. (Nasdaq: RLYB) is poised to begin screening for its Phase 2 clinical trial of RLYB212 in pregnant women at elevated risk for alloimmunization and fetal and neonatal alloimmune thrombocytopenia (FNAIT) in the fourth quarter of 2024. The company has secured Clinical Trial Application (CTA) approvals from the European Medicines Agency (EMA) and the United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA).
Stephen Uden, M.D., Chief Executive Officer of Rallybio, stated, “Advancing RLYB212 into a Phase 2 trial marks a significant achievement for Rallybio. With clinical trial application (CTA) approvals in-hand, our team is activating clinical sites, and we expect to initiate screening for pregnant women at higher risk for alloimmunization and fetal and neonatal alloimmune thrombocytopenia (FNAIT) in the coming weeks.”
RLYB212 Program Advancement
Screening is ongoing in Rallybio’s FNAIT natural history study, with over 13,000 pregnant women screened as of November 1, 2024. European sites have transitioned from the natural history study to the Phase 2 trial, continuing to collect natural history data in women at higher risk for HPA-1a alloimmunization who do not receive RLYB212.
Results from the Phase 1b proof-of-concept study were published in Thrombosis and Haemostasis in August 2024. Additional publications, including the rationale and modeling supporting the RLYB212 Phase 2 dose regimen, are expected later this year.
ASH Presentation on RLYB212 Preclinical Data
Data from a preclinical model demonstrating that prophylactic administration of RLYB212 safely and effectively prevents FNAIT in pregnant mice will be presented at the American Society of Hematology (ASH) Annual Meeting in December 2024. The presentation, titled "Prophylactic Administration of HPA-1a–Specific Antibody RLYB212 Safely Prevents Fetal/Neonatal Alloimmune Thrombocytopenia in Pregnant Mice," highlights the potential of RLYB212 in FNAIT prevention.
Epidemiological Analysis
Rallybio presented data from an epidemiological analysis quantifying the proportion of women of non-Caucasian ancestries carrying genetic markers for higher FNAIT risk (HPA-1a negative, HLA-DRB3*01:01 positive) at the NORD Rare Diseases and Orphan Products Breakthrough Summit and the American Society of Human Genetics (ASHG) Annual Meeting. The data indicates that over 30,000 pregnancies annually are at higher risk for FNAIT in North America and major European countries alone.
RLYB116 Program Update
RLYB116 manufacturing work was successfully completed in Q3 2024. Rallybio anticipates that process enhancements from this work will improve the tolerability of RLYB116. Additional complement biomarker characterization suggests that RLYB116 led to greater sustained reductions in free C5 than initially understood. Rallybio believes there is an opportunity to pursue indications beyond generalized myasthenia gravis, including paroxysmal nocturnal hemoglobinuria and antiphospholipid syndrome at doses tested in the Phase 1 MAD study. Updates on RLYB116 are expected in December 2024.
Preclinical Programs
Rallybio is advancing its preclinical programs, seeking alternative options such as partnerships and non-dilutive financing. Nonclinical data on RLYB332, a long-acting version of the RLYB331 anti-matriptase-2 antibody, will be presented at the upcoming ASH Annual Meeting. Rallybio and Exscientia remain on track to nominate an ENPP1 inhibitor development candidate for hypophosphatasia (HPP) in December 2024.
Financial Position
Rallybio reported $75.1 million in cash, cash equivalents, and marketable securities as of September 30, 2024, providing a cash runway into mid-2026.
