Rare Disease Biotech Rallybio Targets $100M IPO

Rallybio Corporation RLYB ended the first quarter with nearly $128 million in the bank, and now it has filed to raise up to $100 million in its IPO to trade on NASDAQ under the symbol RLYB.
The news comes days after Rallybio established proof of concept for its lead program, RLYB211, in fetal and neonatal alloimmune thrombocytopenia (FNAIT).
This rare disease causes a mother’s immune system to attack her fetus or newborn child’s platelets, the blood cells involved in clotting.
RLYB211 is a polyclonal antibody treatment made by purifying antibodies from donated plasma and is designed to clear fetal platelets from the mother’s circulation, preventing the immune attack against them.
Data from the first cohort showed the candidate could “rapidly and completely clear” HPA-1a positive platelets from those without natural antigen defense.
Six male participants saw their antigens cleared with a mean half-life of 0.32 hours, compared to the two on placebo with a mean half-life of 65.29 hours.
The IPO proceeds will fund the completion of the Phase 1/2 trial for RLYB211 and push a second FNAIT candidate, a monoclonal antibody dubbed RLYB212, into the clinic in Q1 of 2022.