OUTCOMES IN INFLUENZA PHASE III/IV CLINICAL TRIALS: A SCOPING REVIEW
Author(s)
Emma Gregory, BA, Hei To Ho, -, Archawin Udomrat, -, Ousmane Tapsirou Ly, MD, MPH, Anastasiia Demidova, MD, Daniel Munblit, MD, PhD, MSc.
King's College London, London, United Kingdom.
King's College London, London, United Kingdom.
OBJECTIVES: Given the global burden of influenza and need for robust meta-analyses to shape evidence-based medicine,(1,2) a relevant core outcome set (COS) may improve alignment between trials, aid comparative assessments and ensure relevant outcomes are captured. Reviewing existing literature comprises the first stage in COS development. We aimed to review the current landscape of outcome selection in influenza clinical trials.
METHODS: The World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, EMBASE and Medline were searched on 4 October 2024 for clinical trials of influenza management in adult and mixed populations since 2000. Phase 3 and/or 4 interventional studies involving ≥1 efficacy outcome in patients with influenza were included. Study characteristics were extracted, including title, included countries, year of publication/registration, phase, intervention/control, influenza severity, sample size and outcomes. Outcomes were mapped to domains per a modified version of the taxonomy by Dodd et al (2018; 3)
RESULTS: In total, 18,040 studies and 1,687 protocols were identified; 12,807 and 1,506 underwent screening and 106 and 148 underwent extraction, respectively. Across the included studies, 1,052 unique outcomes were identified: 165 primary, 764 secondary and 123 ‘other’ or ‘safety’. The three most frequently reported domains were symptom alleviation (n=192; 18.3%), viral kinetics/load (148; 14.1%), and complications (74; 7.0%). Overall, 59 outcomes (5.6%) were classified under a health‑related quality of life (HRQoL) domain.
CONCLUSIONS: There is frequent utilisation of symptom-focused and viral load efficacy outcomes, with comparatively limited assessment of complications. Future studies should prioritise clinically meaningful endpoints that distinguish symptomatic relief from altered disease course. Additionally, there was limited reporting of HRQoL endpoints, suggesting underrepresentation of patient-centred perspectives. A COS could improve harmonisation and ensure consistent capture of outcomes relevant to patients, clinicians, payers and policymakers. REFERENCES: [1] World Health Organization. 2025; [2] Juliano et al. Lancet. 2018; [3] Dodd et al. J Clin Epidemiol. 2018
METHODS: The World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, EMBASE and Medline were searched on 4 October 2024 for clinical trials of influenza management in adult and mixed populations since 2000. Phase 3 and/or 4 interventional studies involving ≥1 efficacy outcome in patients with influenza were included. Study characteristics were extracted, including title, included countries, year of publication/registration, phase, intervention/control, influenza severity, sample size and outcomes. Outcomes were mapped to domains per a modified version of the taxonomy by Dodd et al (2018; 3)
RESULTS: In total, 18,040 studies and 1,687 protocols were identified; 12,807 and 1,506 underwent screening and 106 and 148 underwent extraction, respectively. Across the included studies, 1,052 unique outcomes were identified: 165 primary, 764 secondary and 123 ‘other’ or ‘safety’. The three most frequently reported domains were symptom alleviation (n=192; 18.3%), viral kinetics/load (148; 14.1%), and complications (74; 7.0%). Overall, 59 outcomes (5.6%) were classified under a health‑related quality of life (HRQoL) domain.
CONCLUSIONS: There is frequent utilisation of symptom-focused and viral load efficacy outcomes, with comparatively limited assessment of complications. Future studies should prioritise clinically meaningful endpoints that distinguish symptomatic relief from altered disease course. Additionally, there was limited reporting of HRQoL endpoints, suggesting underrepresentation of patient-centred perspectives. A COS could improve harmonisation and ensure consistent capture of outcomes relevant to patients, clinicians, payers and policymakers. REFERENCES: [1] World Health Organization. 2025; [2] Juliano et al. Lancet. 2018; [3] Dodd et al. J Clin Epidemiol. 2018
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
CO223
Topic
Clinical Outcomes
Topic Subcategory
Clinical Outcomes Assessment
Disease
Infectious Disease (non-vaccine), Respiratory-Related Disorders (Allergy, Asthma, Smoking, Other Respiratory)