Rallybio's Thrombocytopenia Candidate Shows Rapid, Complete Elimination Of Transfused Platelets

Rallybio Corporation RLYB announced preliminary results from its ongoing Phase 1b proof-of-concept study of RLYB212 to prevent fetal and neonatal alloimmune thrombocytopenia.
The data demonstrate that one week after a single subcutaneous dose, RLYB212 could rapidly eliminate transfused HPA-1a positive platelets compared to placebo in a challenge model of a catastrophic fetal-maternal hemorrhage.
Additional pharmacokinetic data suggests the opportunity for less frequent dosing.
Consistent with previously reported data, these preliminary results showed acceptable safety and tolerability with no serious adverse events.
Martin Mackay, the CEO, said, "we have now commenced dosing under an amended protocol that increases the dose of RLYB212. We expect the broader range of pharmacokinetic and pharmacodynamic data to enable substantive modeling of the concentration-effect relationship, further informing dosing for a future registrational study. We look forward to discussing these proof-of-concept data in the first quarter of 2023."
In May, the company announced worldwide exclusive rights to Sanofi SA's KY1066, dubbed RLYB331, a preclinical antibody for severe anemia in blood disorders.
The licensing agreement marked the first business development transaction since its IPO in 2021.
Price Action: RLYB shares are up 2.78% at 13.86 on the last check Wednesday.