New York, May 23, 2026, 13:05 (EDT)
Korro Bio Inc (KRRO.O) finished Friday at $11.61, gaining 3.66% for the session and up about 14% since May 15. The stock, listed on the Nasdaq, is now paused until Tuesday as U.S. equity markets are shut for Memorial Day on Monday.
Korro is looking to steer the story back to its RNA-editing work after shaking up its alpha-1 antitrypsin deficiency, or AATD, program. This comes after the company tapped KRRO-111 as the AATD candidate on May 19, following a setback with its earlier drug, KRRO-110. KRRO-110 made the right protein in patients, but levels missed Korro’s target after the first dose.
RNA editing changes the temporary RNA code after it’s copied from DNA, before the body makes a protein. For Korro, the main market question hasn’t gone away: will its OPERA platform make enough of the right protein in humans after a setback in trials, or will positive effects stay limited to animals and lab tests?
The stock beat the market Friday. The Nasdaq Composite added 0.2% Friday and 0.5% on the week. The Russell 2000 jumped 0.9% Friday and 2.7% for the week, AP data showed.
Korro said its KRRO-111 candidate led to more than 90% editing of the SERPINA1 transcript in vivo, which gave about 90% repaired functional alpha-1 antitrypsin protein in plasma in a mouse model. SERPINA1 is the gene linked to AATD. CEO Ram Aiyar called it the “highest level of SERPINA1 editing reported to date using RNA editing” and said Korro was “well-capitalized to report clinical data from both programs.” Korro Bio, Inc.
KRRO-111 is a GalNAc-conjugated oligonucleotide. That’s a type of small RNA-targeting drug hooked to a sugar tag so it goes to the liver. Korro says it’s delivered with a shot under the skin. The drug is meant to use ADAR, a natural RNA-editing enzyme, to fix the faulty genetic message behind the disease.
Korro ended the first quarter with $157.1 million in cash, cash equivalents and marketable securities, saying that should cover operations into the back half of 2028. The company reported a net loss of $19.6 million for the quarter, less than the $23.4 million loss a year ago. Korro had no collaboration revenue in Q1 after putting its Novo Nordisk partnership on hold.
Analysts aren’t calling it a full win this week. H.C. Wainwright’s Mitchell Kapoor cut his price target on Korro to $15 from $20 but kept a Buy. He pointed to the company’s first-quarter financing, according to a Fly note on TipRanks.
Wave Life Sciences is raising the bar in AATD RNA editing. The company, Korro’s main public peer, said May 18 that its WVE-006 candidate showed wild-type M-AAT at 64% of total AAT and cut Z-AAT by 71% in a 200 mg biweekly group. Wave expects FDA feedback on accelerated approval around mid-2026. Chief Medical Officer Christopher Wright said the company has seen “consistent results across multiple cohorts.” University of Chicago’s D. Kyle Hogarth called the findings a “major step forward.” SEC
But there’s still a clear risk. Korro’s latest quarterly filing says early-stage results may not predict what happens later, and the company hasn’t made product sales before. It may need a lot more cash. The filing also mentions the REWRITE trial, where the preclinical data didn’t lead to the expected protein levels in AATD patients.
Short week coming, and activity could stay light. Still, Korro’s investor calendar points to EASL Congress 2026 on May 27. Traders look for extra scientific updates, any fresh analyst comments, and watch how the stock trades after Memorial Day.
KRRO bounced back from early weakness last week, lifted by small-cap strength and news of a new AATD candidate. But the real test will come with human data that proves the platform is more than just potential.
