Korro Bio Faces Setbacks: Lead Drug Disappoints, Novo Nordisk Partnership Paused

Korro Bio, a Massachusetts-based biotechnology company, has announced a series of significant setbacks, including disappointing results for its lead drug candidate and a pause in its partnership with Novo Nordisk. These developments have led to a substantial workforce reduction and a strategic pivot in the company's research focus.

KRRO-110 Falls Short in AATD Trial

Korro's lead candidate, KRRO-110, an RNA editing oligonucleotide encapsulated in a lipid nanoparticle (LNP), has failed to meet expectations in a phase 1/2a trial for alpha-1 antitrypsin deficiency (AATD). The drug, designed to repair a mutation and restore normal levels of AAT protein, showed lackluster results in increasing functional AAT levels.

Initial analysis revealed that the pharmacokinetics of the delivery components differed between healthy volunteers and AATD patients. As a result, Korro has abandoned plans to complete additional single-ascending dose cohorts and is reassessing the next steps for the multiple-ascending dose part of the trial.

Strategic Pivot and Workforce Reduction

In response to these setbacks, Korro Bio is making significant changes to its strategy and operations:

1. The company is shifting its AATD program focus to GalNAc-conjugated delivery, aiming to enter clinical trials with this approach by 2027.

2. Korro will lay off 34% of its workforce, following a previous 20% reduction in May. This move is intended to extend the company's cash runway into the second half of 2027.

3. The biotech is now prioritizing KRRO-121, a GalNAc-conjugated construct for hyperammonemia, with plans to begin human trials in the second half of 2026.

Novo Nordisk Partnership on Hold

Adding to Korro's challenges, its partnership with Novo Nordisk has been paused for 12 months. The collaboration, which initially included a commitment of up to $530 million from Novo Nordisk, is under reassessment. Both companies have agreed to reevaluate the rationale for the current target under the first research program, with Korro winding down related R&D activities.

These developments have had a significant impact on Korro Bio's market position, with the company's stock price plummeting 79% to $6.55 in premarket trading. In contrast, shares of competitor Wave Life Sciences, which is developing a rival GalNAc-conjugated RNA editing oligonucleotide for AATD, rose 6% to $7.35.