Rallybio reassembles behind version 2.0 of fetal blood disorder med

Rallybio is prioritizing version 2.0 of a therapy to treat a fetal and neo-natal blood condition, squashing work on the med’s first iteration as a result. 

The 2018 Fierce 15 winner will discontinue development of RLYB211, the biotech's once-lead asset for the prevention of fetal and neonatal alloimmune thrombocytopenia, according to a fourth-quarter earnings report Monday. Instead, the company will rally behind the updated version, RLYB212, on the heels of what it believes is encouraging phase 1b data. RLYB212 was able “to rapidly and completely eliminate transfused, HPA-1a positive platelets in HPA-1a negative subjects," Rallybio said in a separate announcement Monday.

That data evidently sealed RLYB211’s fate, with the asset now gone from the company’s pipeline. RLYB211 was a polyclonal antibody administered via IV bolus injection whereas RLYB212 is a monoclonal antibody given through an easier, subcutaneous injection. Rallybio cited 212’s favorable development profile and smoother manufacturing process as part of the reason for switching up its lead horse. 

Rallybio has bullishly estimated that RLYB212 could be ready for a registrational study once the company finalizes a dose. 

The changing of the guard atop the company’s pipeline comes roughly three months after Rallybio inked a new partnership with AbCellera to identify and develop new antibody-based therapies for rare diseases. The two companies did not disclose how much the partnership was worth but Rallybio is on the hook for up to five rare disease targets, one of which remains undisclosed but is slated for metabolic diseases, according to Rallybio’s pipeline

The company’s name has lived up to itself, with shares climbing in recent months amid an unrelenting downturn for other public biotechs. Rallybio’s share price overall is down nearly 30% over the last six months, from $11.32 to $8 as of Monday morning, but it's up more than 70% since the middle of December.

Rallybio had $169 million in cash and equivalents as of the end of 2022 to realize the potential of RLBY212, thanks in large part to a $55 million public offering in November. The company expanded its R&D spend from $26.9 million in 2021 to $40.7 million in 2022.