AstraZeneca receives award through BARDA’s Rapid Response Partnership Vehicle to advance development of tozorakimab in the treatment of severe viral lower respiratory tract disease

Partnership underscores importance of investigating potential therapies that may
address unmet needs for patients with viral lung infection requiring supplemental
oxygen

AstraZeneca is partnering with the US government to evaluate the effect of tozorakimab, an investigational product, on the progression of acute respiratory distress syndrome (ARDS) in patients hospitalized with severe viral lower respiratory tract disease (LRTD). This project is supported by a $48.4 million award issued through the Rapid Response Partnership Vehicle (RRPV), a consortium funded by the Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response (ASPR) within the US Department of Health and Human Services (HHS).

The project will support the ongoing Phase III TILIA trial, which is evaluating the efficacy and safety of tozorakimab, a monoclonal antibody targeting interleukin-33 (IL-33), as an add-on to standard of care in patients with viral lung infection requiring supplemental oxygen on the prevention of death or progression to invasive mechanical ventilation/extracorporeal membrane oxygenation.1 IL-33 is an upstream mediator of broad immune responses.2,3

Severe viral LRTD is an important clinical challenge, particularly among hospitalized patients at risk of disease progression. Severe viral LRTD may develop when the body’s immune response to respiratory viral infection becomes dysregulated, which can drive inflammation and contribute to disease progression.4 Viral threats can become particularly acute during seasonal surges or periods of widespread transmission that may drastically increase the number of patients at risk. Treatment options targeting the dysregulated host immune response are needed.

The burden of respiratory viral infections is significant even during periods of typical viral circulation. In 2019, there were 94 million cases of respiratory viral infections globally, which led to 11 million hospitalizations and more than 1 million in-hospital deaths.5 Patients hospitalized with viral LRTD who require supplemental oxygen may experience further disease progression and require intensive supportive care, such as invasive mechanical ventilation.6,7

Rick R. Suárez, US President and Head of the US BioPharmaceuticals Business Unit, AstraZeneca, said: “Severe respiratory infections put lives at risk every year. We cannot wait for the next health crisis before we strengthen our treatment options. Government and industry need to do that work together. This award from BARDA supports the Phase III TILIA trial, testing whether tozorakimab can help prevent patients hospitalized with viral lower respiratory tract disease from progressing to critical illness. Our goal is to expand treatment options for patients and help the US prepare for future respiratory viral threats.”

Tozorakimab is a potent human monoclonal antibody that binds to IL-33. It can inhibit signaling of both the reduced and oxidized forms of IL-33 (IL-33red and IL-33ox) via distinct ST2 and RAGE/EGFR signaling pathways, respectively.8,9,10

This project has been supported in whole or in part with federal funds from the US Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA), under Agreement Number: 75A50123D00005.

To learn more about the award, visit rrpv.org/awards/.

Notes

Tozorakimab 
Tozorakimab is a potent human monoclonal antibody that binds to IL-33. It can inhibit signaling of both the reduced and oxidized forms of IL-33 (IL-33red and IL-33ox) via distinct ST2 and RAGE/EGFR signaling pathways, respectively.8,9,10 

TILIA Phase III trial1
TILIA (NCT05624450) is a Phase III, randomized, double-blind, placebo-controlled, parallel-group trial evaluating the efficacy and safety of tozorakimab vs placebo as an add-on to standard of care in adults hospitalized with viral lung infection requiring supplemental oxygen. The primary endpoint is the proportion of participants who die or progress to invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO) by Day 28.

References

  1. ClinicalTrials.gov. Efficacy and Safety of Tozorakimab in Patients Hospitalised for Viral Lung Infection Requiring Supplemental Oxygen (TILIA). NCT05624450. Accessed September 17, 2026.
  2. Ostridge K, De Palo G, Morelli T, et al. Late Breaking Abstract - IL-33 signalling pathway biomarkers in severe viral lower respiratory tract disease: interim results from the prospective, observational UNIVERSAL study. Eur Respir J. 2024;64(suppl 68):PA2398. doi:10.1183/13993003.congress-2024.PA2398
  3. Liew FY, Girard JP, Turnquist HR. Interleukin-33 in health and disease. Nat Rev Immunol. 2016;16(11):676-689. doi:10.1038/nri.2016.95 
  4. Yunis J, Short KR, Yu D. Severe respiratory viral infections: T-cell functions diverging from immunity to inflammation. Trends Microbiol. 2023;31(6):644-656. doi:10.1016/j.tim.2022.12.008
  5. Maslova E, Rafferty Q, Lei J, et al. Global viral lower respiratory disease episodes, hospitalisations, and clinical outcomes by aetiology, 2010–2021. Infect Dis Ther. 2026;15(9):2523-2543. doi:10.1007/s40121-026-01406-4
  6. Rosero CI, Gravenstein S, Saade EA. Influenza and Aging: Clinical Manifestations, Complications, and Treatment Approaches in Older Adults. Drugs Aging. 2025;42(1):39-55. doi:10.1007/s40266-024-01169-y
  7. Serafim RB, Póvoa P, Souza-Dantas V, Kalil AC, Salluh JIF. Clinical course and outcomes of critically ill patients with COVID-19 infection: a systematic review. Clin Microbiol Infect. 2021;27(1):47-54. doi:10.1016/j.cmi.2020.10.017 
  8. England E, Rees DG, Scott IC, et al. Tozorakimab (MEDI3506): an anti-IL-33 antibody that inhibits IL-33 signalling via ST2 and RAGE/EGFR to reduce inflammation and epithelial dysfunction. Sci Rep. 2023;13:9825.
  9. Cohen S, Strickson S, Scott IC, et al. Distinct Pharmacological Profiles of IL-33 Antibodies. Am J Resp Crit Care Medicine. 2024;209(1):A3294.
  10. Strickson S, Houslay KF, Negri VA, et al. Oxidised IL-33 drives COPD epithelial pathogenesis via ST2-independent RAGE/EGFR signalling complex. Eur Respir J. 2023;62:2202210.