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Casirivimab plus imdevimab decreases mortality only in seronegative persons hospitalized with COVID-19
Clinical Question
Does the combination of the 2 monoclonal antibodies casirivimab and imdevimab (REGN-COV2) improve outcomes in adults hospitalized with COVID-19?
Bottom line
In mostly unimmunized seronegative adults hospitalized with COVID-19, adding a single infusion of casirivimab and imdevimab to usual care decreased 28-day mortality and decreased the need for ventilation compared with usual care alone. 2b
Reference
Study design: Randomized controlled trial (nonblinded)
Funding: Government
Setting: Inpatient (any location)
Synopsis
The RECOVERY trial was a government-funded open-label trial in the United Kingdom that randomized thousands of hospitalized patients with COVID-19 into several different treatment arms, including azithromycin, colchicine, lopinavir-ritonavir, tocilizumab, convalescent plasma, low-dose dexamethasone, or usual care. The trial was designed to be adaptive and could include additional wings as new potential therapies are identified. This report is on adults who were randomized to receive usual care (n = 4946) or usual care plus the monoclonal antibodies (MABs) casirivimab and imdevimab (n = 4839). One-third of the participants were seronegative for COVID-19 and just more than half were seropositive (the remainder had unknown antibody status). Only 8% of the participants were known to have at least one dose of a COVID-19 vaccine. The monoclonal antibodies were administered together as a single infusion containing 4 grams of each. More than 90% of the participants in both groups had received systemic corticosteroids, and the rate of co-interventions with other agents (such as remdesivir, tocilizumab, or sarilumab) were similar between the intervention and usual care groups. The overall 28-day mortality rate was similar between the treatment groups (19% for the MAB group vs 21% for the usual care group) as was length of stay (10 days) and other measures of clinical deterioration. However, among those who were seronegative, the mortality was lower in those who received the MABs (24% vs 30%, respectively; number needed to treat [NNT] = 19; 95% CI 12 - 42). Similarly, those who received the MABs had a shorter median length of stay (13 days vs 17 days) and fewer of them needed ventilation (28% vs 33%; NNT = 24; 13 - 185). The authors report that serious adverse events occurred in less than 1% of the MAB-treated participants.
Reviewer
Henry C. Barry, MD, MS
Professor
Michigan State University
East Lansing, MI
Comments
Casirivimab plus imdevimab decreases mortality only in seron
Result are reasonably impressive for the reported subgroup. The reviewer does not mention is this was a pre-planned analysis or a post-hoc one. If it was post-hoc, I'd be a be suspicious of the validity of the result (although a 6% absolute decrease in mortality is hard to ignore).
no
very interesting