Arcturus Therapeutics is doubling down on mRNA technology.
The biotech
said
Monday that it’s prioritizing its experimental mRNA drugs, with a focus on programs for cystic fibrosis and a rare disease called ornithine transcarbamylase (OTC) deficiency. The decision is expected to extend Arcturus’ runway into 2028.
Investors appeared pleased with the move. Shares of Arcturus
$ARCT
rose as much as 17% in trading on Tuesday morning, but later settled to about a 3% gain. William Blair analyst Myles Minter wrote in a note to investors that the shift could boost Arcturus’ efforts to “diversify from vaccines and into a bona fide rare disease company.”
Arcturus’ vaccines, which include an approved Covid-19 shot in Japan and Europe as well as two experimental shots for seasonal flu and bird flu, are partnered with CSL.
The cystic fibrosis program, known as ARCT-032, has garnered particular excitement, with several analysts asking execs about the nature of the trial, the likely regulatory pathway and competition with other therapies during Monday’s earnings call. The company said it expects to report initial Phase 2 data in “mid-2025.”
Arcturus refined its strategy after another prominent mRNA-based cystic fibrosis drug ran into a hurdle. Earlier this month, Vertex
paused
a Phase 1/2 trial of VX-522, its inhaled mRNA treatment for cystic fibrosis, due to a “tolerability issue.” Vertex’s drug came from a partnership with Moderna.
Both the Arcturus and Vertex programs are being tested in patients who don’t respond to an approved class of drugs known as CFTR inhibitors, which includes some of Vertex’s cystic fibrosis therapies. The companies are trying to deliver mRNA with instructions for working copies of the CFTR protein to lung cells using lipid nanoparticles.
During Monday’s call, Arcturus CEO Joseph Payne said he’s confident Arcturus’ platform will help the company avoid similar tolerability issues, noting that it uses different LNP chemistry and mRNA purification processes than its competitors.
And if the Phase 2 data are good enough, the company may seek accelerated approval.
“Whenever you see excellent Phase 2 data, that would always warrant a discussion with regulators to accelerate the approval pathway,” Payne said. “We have not shared any data, so we don’t know. It would be too early for me to guide whether this is good or great or excellent data.”
The OTC deficiency program, called ARCT-810, is currently in a Phase 2 trial that’s expected to read out by the end of June.
Editor’s note: This article was updated to correct that Arcturus’ cystic fibrosis and OTC deficiency programs are not self-amplifying mRNA drugs.