Objectives: Evidence is emerging on the effectiveness of novel neutralizing monoclonal antibodies (mAbs) for the treatment of COVID-19 in the community immediately after confirmation of infection. We conducted an early-stage economic evaluation to estimate the costs and benefits of neutralising mAbs in England.

Methods: A decision model was constructed to compare neutralising mAbs, administered as a single infusion, as an adjunct to standard of care compared to standard of care (SoC) alone in patients with PCR confirmed COVID-19. SoC comprises self-isolation and advice on management of symptoms for patients at home. Patients requiring hospitalisation may receive oxygen or ventilation support of varying intensities and remdesivir according to UK guidance in place at the time of analysis. A decision tree model represents the pathway for patient up to their initial hospitalisation followed by a partitioned survival model to calculate consequences in hospital and beyond. People with confirmed COVID-19 entering the model are assessed by subgroups defined by their age, antibody status and immune system status. Health service costs and quality adjusted life years were calculated. Treatment effects were largely drawn from the REGN-COV 2067 trial.

Results: mAbs are more likely to represent a cost-effective use of resources in seronegative patients, with the ICER above typical thresholds in those who are seropositive (with a lower risk of hospitalisation and in-hospital mortality). The relationship between cost effectiveness and age is non-monotonic. Increasing risk from COVID-19 infection with age is offset by shorter life expectancy and quality of life with increasing age. This turning point occurs around 80 years of age.

Conclusions: The cost-effective use of mAbs at the point of confirmed infection confirmation requires careful selection of patients according to their risk of hospitalisation and mortality.