Researchers from the USA conducted a large-scale study to evaluate the efficacy of neutralizing monoclonal antibodies (MAbs). The study findings published on a pre-print server state that timing is a crucial factor in determining the efficacy of MAbs against COVID-19. A total of 2,818 symptomatic COVID-19 patients (average age: 67 years) who received MAB therapy were analyzed. Hypertension and obesity were the most common comorbidities observed among the patients. In this report, the scientists described the effectiveness of two MAB therapies, including bamlanivimab and casirivimab/imdevimab.
The adult COVID-19 patients who received MAB therapy at ambulatory units or emergency departments between November 2020 and January 2021 were included in the study. The clinical outcomes of MAB-treated patients were compared with those who were eligible but did not receive MAB therapy. About 89% of the patients received bamlanivimab, whereas 11% received casirivimab/imdevimab.
The average duration between symptom onset and MAB infusion was 6 days. To investigate the hospitalization rate, the scientists specifically analyzed a total of 2,721 patients with known symptom onset dates. In this subgroup, the rates of hospitalization for patients who received MAB therapy within 4 days, 5 – 7 days, or more than 8 days of symptom onset were 4.4%, 5%, and 6.1%, respectively. Of 2,713 patients who were eligible for MAB therapy but did not receive it, about 5% and 7% were presented to the emergency department and hospitalized, respectively, within 28 days of a positive COVID-19 test. The study results indicate that the timings of mAB therapy initiation are a crucial determinant of treatment efficacy.