Tixagevimab/cilgavimab 600mg IM x 1 dose has demonstrated a 50.5% relative risk reduction (RRR) in COVID-19 hospitalization and death in unvaccinated, non-hospitalized adults with mild- moderate COVID-19 (TACKLE), which is lower than the RRR seen with other COVID-19treatments in similar trials. Tixagevimab/cilgavimab is likely ineffective against many currently circulating VoCs including BA. 4.6, BF. 7, BA. 2.75.2, BQ 1, BQ 1.1 and XBB where 300-1000-fold reductions in binding are seen.
If tixagevimab/cilgavimab is used as a last line treatment in cases where nirmatrelvir/ritonavir, IV remdesivir or sotrovimab cannot be used, disclosure to patients of risks, including cardiovascular serious adverse events (SAEs), and benefits and consideration of individual circumstances (clinical and immune status, patient values, logistics) is necessary. The convenience of the IM route of administration of tixagevimab/cilgavimab should not be the primary indication for use.