Korro Bio sings to the tune of $116M for its OPERA RNA editing program

Stethoscope on dollars
Korro Bio launched out of Atlas Venture in 2019. (Foremniakowski/GettyImages)

Ticket sales for Korro Bio's second operatic financing round landed at $116 million as the biotech builds up an investor base to bankroll its OPERA platform for RNA editing. 

The series B gives the company capital to fund its RNA editing system, which will first be tested in patients with an inherited genetic disorder. Known as alpha-1 antitrypsin deficiency, or AATD, the disorder leads to liver and lung diseases. 

Korro plans to enter the clinic in 2023 for the indication, said CEO Ram Aiyar, Ph.D., in an emailed statement. Aside from liver conditions, the Cambridge, Massachusetts biotech is looking at central nervous system targets, the CEO added.

Companies developing potential treatments for the disease have experienced their share of ups and downs in the past year. Vertex Pharmaceuticals ditched its AATD drug in June despite a phase 2 study that technically succeeded but wouldn't be enough to "translate into substantial clinical benefit," the cystic fibrosis drugmaker said. 

RELATED: Vertex’s rare lung disease drug hits phase 2 goal—but still winds up on the scrapheap

Takeda's $300 million upfront bet on Arrowhead Pharmaceuticals' RNA-silencing treatment delivered results showing it reduced scarring in a rare liver disease linked to AATD in a phase 2 test in April. And, Dicerna said its RNA-silencing drug lowered levels of AAT protein in patients' blood in a phase 1 study in people with a liver disease stemming from AATD. Gene editing leader Intellia also has studied the disease in nonhuman primates. 

Now, Korro wants to enter the arena for the rare disease with an RNA editing drug that changes a single base on RNA with specificity. This is done using Korro's OPERA platform that uses a base editing system found in the body, called adenosine deaminase acting on RNA, or ADAR. 

That's not to be confused with ADARx Pharmaceuticals, which secured $75 million in a September series B for its own RNA editing, also to be tested in AATD, among eight other programs in the works. 

Korro, founded out of Atlas Venture in 2019, aims to sidestep the challenges of gene therapy and gene editing by reducing off-target effects, making edits to RNA without permanently changing the genome and by dosing more than once. 

RELATED: Korro Bio hits the high notes with $91.5M series A to run its OPERA RNA platform

The startup landed Aiyar as CEO in November 2020, two months after Korro's $91.5 million series A. Korro poached Aiyar after he led Corvidia Therapeutics' $2.1 billion exit to Novo Nordisk in June of that year as chief financial officer.

Eventide Asset Management led Korro's series B. Other investors included Fidelity, Invus, Point72, Verition, Monashee, Sixty Degree Capital, Atlas, NEA, Wu Capital and about half a dozen others.