Leyden Labs has published results from pre-clinical and clinical studies of its PanFlu (CR9114) intranasal antibody in the journal Science Translational Medicine. According to the company, two Phase 1 trials that enrolled a total of 143 participants demonstrated that PanFlu was safe and well tolerated. The studies also demonstrated that repeat dosing allowed for maintenance of steady state concentrations of functional CR9114 in the nose, the company said.
The company also says that in a preclinical challenge study, non-human primates that were administered the human formulation of CR9114 via the same device used for human delivery were protected against infection. According to the announcement, the non-human primates experienced significantly lower viral load of H1N1 influenza and significantly lower replication of the virus compared to non-human primates that got a placebo.
Initiation of a Phase 1 trial of the nasal spray was announced in 2023, two years after the company said that Nanopharm would be developing intranasal formulations of CR9114 for use in Phase 1 studies. In 2025, Leyden Labs secured at least €120 million for continued development of PanFlu, including a $70 million funding round, a €20 million financing deal with the European Investment Bank, and €30 million in equity financing from the European Innovation Council (EIC) Fund and Invest-NL.
Leyden Labs Chief Scientific Officer Clarissa Koch commented, “These results demonstrate the feasibility of our ongoing efforts to stop viruses at the portal of entry rather than through the traditional route of intravenous or intramuscular delivery. Our lead candidate for PanFlu contains CR9114, the broadest human monoclonal influenza antibody identified to date. These new data across species provide important validation of our approach to effectively protect against respiratory viruses with our antibody-based nose sprays.”
Read the Leyden Labs press release
