RSV Neutralizing Antibodies in Dried Blood.

Background: The key correlate of protection of respiratory syncytial virus (RSV) vaccines and monoclonal antibodies (mAbs) is virus neutralization, measured via sera obtained through venipuncture. Dried blood obtained with a finger prick can simplify acquisition, processing, storage, and transport in trials and thereby reduce costs. In this study, we validate an assay to measure RSV neutralization in dried capillary blood.
Methods: Functional antibodies were compared between matched serum and dried blood samples from a phase 1 trial with RSM01, an investigational anti-RSV prefusion F mAb. Hep-2 cells were infected with a serial dilution of sample-virus mixture by using RSV-A2-mKate to determine the half-maximal inhibitory concentration. Stability of dried blood was evaluated over time and during temperature stress.
Results: Functional antibodies in dried blood were highly correlated with serum (R2 = 0.98, P < .0001). The precision of the assay for dried blood was similar to serum. The function of mAb remained stable for 9 months at room temperature and frozen dried blood samples.
Conclusions: We demonstrated the feasibility of measuring RSV neutralization using dried blood as a patient-centered solution that may replace serology testing in trials against RSV or other viruses, such as influenza and SARS-CoV-2. Clinical Trials Registration.  NCT05118386 (ClinicalTrials.gov).
Competing Interests: Potential conflicts of interest. University Medical Center Utrecht (UMCU) has received major funding (>€100 000 per industrial partner) for investigator-initiated studies from AbbVie, MedImmune, AstraZeneca, Sanofi, Janssen, Pfizer, MSD, MeMed Diagnostics, the Bill and Melinda Gates Foundation, Bill & Melinda Gates Medical Research Institute, and the Dutch Lung Foundation. UMCU has received major funding as part of the public-private partnership Innovative Medicines Initiative–funded RESCEU and PROMISE projects with partners GSK, Novavax, Janssen, AstraZeneca, Pfizer, and Sanofi. UMCU has received major funding by Julius Clinical for participating in clinical studies sponsored by MedImmune and Pfizer. UMCU received minor funding (€1000–€25 000 per industrial partner) for consultation and invited lectures by AbbVie, MedImmune, Ablynx, Bavaria Nordic, MabXience, GSK, Novavax, Pfizer, Moderna, Astrazeneca, MSD, Sanofi, and Janssen. L. J. B. and N. I. M. have regular interaction with pharmaceutical and other industrial partners. They have not received personal fees or other personal benefits. L. J. B. is the founding chair of the ReSViNET Foundation. J. T. W. is an employee at the Bill & Melinda Gates Medical Research Institute. A. D.-C. and T. J. R. are supported by funding from the Intramural Research Program of the NIAID. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
(© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)