Korro Bio Abandons Lead Genetic Disease Drug Candidate KRRO-110 After Disappointing Trial Data

Korro Bio announced it is abandoning its lead clinical candidate, KRRO-110, developed for Alpha-1 antitrypsin deficiency (AATD), after it failed to achieve expected protein production in a Phase I/IIa trial, leading to disappointing clinical results1 3 6.

The abrupt trial failure caused Korro Bio’s stock price to plummet by approximately 80% and triggered major restructuring, including laying off about a third of its workforce and the resignation of its chief medical officer1 3 5.

KRRO-110 is an RNA editing oligonucleotide delivered via a lipid nanoparticle system, intended to treat AATD, a genetic disorder resulting in low levels of the protective AAT protein1 3.

The trial results were viewed as non-competitive compared to rival approaches from Wave Life Sciences and Beam Therapeutics, and the outcome placed Korro further behind its competitors1 3.

In light of KRRO-110's underperformance, Korro Bio is pivoting towards a new therapeutic candidate for AATD using a GalNAc conjugation mechanism, which it aims to nominate in the first half of 20261 5.

Korro has paused additional dosing cohorts for KRRO-110 and is accelerating the ramp-up of its GalNAc-based program, planning a clinic entry by 2027 for the new candidate5.

A partnership with Novo Nordisk was also put on hold for a year as both parties reassess the rationale for their joint cardiometabolic research program in light of recent developments1 3 5.

Prior to the negative results, KRRO-110 had received orphan drug designation from both the European Medicines Agency and the U.S. FDA for AATD in 20257 9.