- The need for more effective protection against influenza continues to grow, as the virus consistently causes significant illness and mortality worldwide
- New human clinical data from Leyden Labs show intranasal delivery of broadly neutralizing antibodies can safely achieve and maintain protective levels at the site of viral entry
- Non-human primate data confirm these antibody levels, attained by low dose administration, are sufficient to protect against influenza infection
- Published today in Science Translational Medicine, the data validate the scientific premise of the Company's pan-influenza nasal spray in development (PanFlu)
LEIDEN, The Netherlands. February 04, 2026 - Leyden Laboratories B.V. (the "Company" or "Leyden Labs") today announced landmark preclinical and clinical data in Science Translational Medicine supporting the development of their antibody-based nasal sprays to prevent influenza infection by neutralizing virus at portal of entry.
The data directly underpin the Company's PanFlu program, which aims to provide broad, immediate protection against influenza through intranasal antibody delivery. In two clinical studies in healthy volunteers, the PanFlu nasal spray was shown to be safe and well tolerated, and the dosing schedule achieved high, sustained concentrations of the active substance (antibody CR9114) in the nasal cavity.
In a third study, intranasal administration of CR9114 protected non-human primates from influenza infection and viral replication.
"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," said Clarissa Koch, Chief Scientific Officer of Leyden Labs.
"This study provides important proof-of-concept preclinical and clinical data for the delivery of monoclonal antibodies by the intranasal route," said Dan Barouch, MD, PhD, of Beth Israel Deaconess Medical Center and a co-author on the paper.
Key Findings:
- Intranasal administration of the pan-influenza antibody CR9114 was safe and well-tolerated in human phase 1 studies of healthy volunteers, including a total of 143 participants, with doses from 0.5 to 10 mg tested.
- Repeated dosing achieves sustained CR9114 concentrations in the nose, overcoming natural clearance mechanisms.
- Intranasal administration of CR9114 in non-human primates provided potent protection against H1N1.
"As we once again face a challenging influenza season, there is a growing need for additional tools that complement vaccination and help people better protect themselves," remarked Boris Juelg, MD, PhD.
Read the article here: https://www.science.org/doi/10.1126/scitranslmed.adz1580
About Leyden Laboratories B.V.
Leyden Labs is working to free people from the threat of respiratory viruses, leveraging its Mucosal Protection Platform to develop a portfolio of candidates aimed at providing protection against influenza, coronaviruses, and other respiratory viruses through a new class of broadly protective nasal sprays.
To learn more, visit www.leydenlabs.com.
About PanFlu candidate CR9114
CR9114, Leyden Labs' lead product candidate for the PanFlu program, is a human monoclonal antibody that protects against influenza in preclinical models. Leyden Labs holds an exclusive license from Janssen Pharmaceuticals, Inc.
Media and Investor Contacts
Leyden Labs Media Contact
Megan Prock McGrath
+1 978-800-7468
media@leydenlabs.com
Leyden Labs Investor Contact
Elizabeth Goodwin
+1 781-460-1784
investor.relations@leydenlabs.com
