AIRNA raises $90 million to make RNA-editing drugs

Pharmaceutical start-up AIRNA has raised $90 million in an oversubscribed series A financing round. The firm aims to produce drugs that edit RNA transcripts in the body.

AIRNA obtained an initial $30 million with support from Arch Venture Partners and the subsequent $60 million in funding through Forbion and Ono Venture Investment.

The RNA-editing approach that AIRNA is developing is based on research published in 2019 by cofounders Thorsten Stafforst of the University of Tübingen and Jin Billy Li of Stanford University. They demonstrated that endogenous human proteins called ADARs (adenosine deaminases acting on RNA) can be recruited to edit specific RNA target sites using an antisense oligonucleotide. Once in place, ADARs convert the nucleoside adenosine to inosine, an atypical nucleoside that gets read by ribosomes as a guanosine.

AIRNA president and CEO Kris Elverum says the company’s technology can help fix genetic mutations such as α1-antitrypsin deficiency (AATD), which can cause lung and liver disease. AIRNA’s therapeutics for AATD are administered subcutaneously and then delivered to hepatocytes in the liver via N-acetylgalactosamine conjugates that recognize receptors on the surface of cells. Using AIRNAs undisclosed chemistry, the therapeutic specifically recruits ADARs to facilitate site-specific RNA editing.

Elverum says AIRNA data suggest its RNA-editing approach results in a potent medication for treating AATD with few off-target impacts. He adds that the company has “solved the in vitro to in vivo challenge,” though he isn’t ready to share specific clinical results.

What Elverum will say is that when it comes to making therapeutics based on RNA editing, AIRNA “clearly has the best science and technology in this space.” But, that space is growing. Several other companies are also developing RNA-editing-based medicines—including Radar Therapeutics, which launched in May with a modified ADAR approach.

Unlike gene therapies that directly edit DNA, RNA-editing therapeutics don’t offer a permanent genetic fix. That’s a benefit, according to Elverum. “One of the powers of RNA editing is that it is temporary,” he says. “You can dose up or down, start or stop [the drug]. It works like a traditional medicine and doesn’t have the significant risks associated with editing DNA.”

The next major milestone for the company, which has sites in Cambridge, Massachusetts, and Tübingen, Germany, is to get its therapeutic into clinical trials. Elverum says trials are scheduled to start next year.