The therapy, developed by RIGImmune, a Yale spinout founded by professors Anna Marie Pyle and Akiko Iwasaki with early support from Yale Ventures and the Blavatnik Fund for Innovation at Yale, was shown safe and well-tolerated, with biomarkers confirming its antiviral mechanism. RIGImmune was acquired this year by Leyden Labs, which now carries the program forward on an exclusive Yale license.

RIG-101 reported positive results from its Phase 1 study and is advancing into Phase 2 clinical development. The therapy was safe and well-tolerated in healthy volunteers and patients with asthma across all dose levels, with up to seven days of daily intranasal dosing, and biomarker analyses confirmed it activated its intended antiviral mechanism in the upper respiratory tract. The next planned study is a human rhinovirus challenge study in patients with asthma.

What differentiates RIG-101 is its approach: rather than targeting a single virus, it acts on RIG-I — a central mediator of innate immunity — to strengthen the body's own antiviral defenses at the respiratory mucosa, where airborne viruses enter. That gives it pan-viral potential. The initial focus is asthma, where respiratory viral infections trigger more than 80% of severe exacerbations.

“These Phase 1 results provide encouraging evidence that RIG-101 has the profile needed to advance into Phase 2 patient studies,” said Susan Sobolov, CTO of Leyden Labs and former President and COO of RIGImmune. “We believe the enhancement of innate antiviral response represents a promising new therapeutic strategy for the prevention of a broad range of respiratory viral infections in vulnerable patients with chronic airway disease.”