Fewer hospitalizations, death with neutralizing monoclonal antibodies for COVID-19

Key takeaways:

• The likelihood for hospitalization and death among adults with COVID-19 decreased with neutralizing monoclonal antibodies.
• If hospitalized, those who received this therapy had reduced measures of severity.

Treatment with neutralizing monoclonal antibodies in COVID-19 outpatients resulted in fewer hospital admissions and deaths vs. no antibody treatment, according to results published in CHEST.

“Real-world data revealed a strong association between receipt of neutralizing monoclonal antibodies (mAbs) and reduced hospitalization and death among COVID-19 outpatients across multiple pandemic phases and provided valuable data to inform scarce resource allocation decisions,” Matthew K. Wynia, MD, MPH, director of the Center for Bioethics and Humanities at University of Colorado, Anschutz Medical Campus, and colleagues wrote.

In a propensity-matched observational cohort study, Wynia and colleagues analyzed 2,675 adult COVID-19 outpatients (40.7% aged 65 years or older; 54.3% women; 82.8% white) treated with mAbs under emergency use authorization between November 2020 and October 2021 to see how this treatment impacted 28-day hospitalization compared with 6,677 adults with COVID-19 (30.2% aged 65 years or older; 55.5% women; 79.7% white) who did not receive mAbs.

In addition to hospitalization, researchers evaluated mortality and hospitalization severity between groups. Subgroup analysis followed the main analysis to see if any findings changed across variants and risk factors.

By day 28, fewer patients who received mAbs vs. patients who did not were hospitalized (4% vs. 7.7%; adjusted OR = 0.48; 95% CI, 0.38-0.6). Patients in this group also had a decreased rate of all-cause 28-day mortality (0.1% vs. 0.9%; aOR = 0.11; 95% CI, 0.03-0.29).

Researchers further reported that reduced hospitalization and mortality among patients treated with mAbs continued at the day-90 evaluation (hospitalization aOR = 0.53; 95% CI, 0.44-0.65; mortality aOR = 0.17; 95% CI, 0.06-0.35).

ED visits occurred more frequently among patients who received mAbs (18.7% vs. 16.9%; aOR = 1.24; 95% CI, 1.09-1.4), but when evaluating the rate of hospitalizations due to an ED visit, researchers found more instances among those who did not receive mAbs (37.6% vs. 16%; aOR = 0.29; 95% CI, 0.21-0.38).

Patients who received mAbs and ended up being hospitalized spent an average of 5.8 days in the hospital, which was less than the average 8.5 days found in hospitalized patients who did not receive mAbs. Additionally, the rate of mechanical ventilation was 16.6% in the group not treated with mAbs, whereas it was only 4.6% in the group treated with mAbs. ICU admission occurred less frequently among the treatment group (12.9% vs. 19.6%).

During subgroup analysis, researchers found that mAb treatment was linked to less hospitalizations when delta was the main variant (aOR = 0.35; 95% CI, 0.25-0.5), as well as when alpha was the primary variant (aOR = 0.67; 95% CI, 0.46-0.98).

The positive impact of mAb in regard to hospitalizations did not differ across demographic (age, sex, race/ethnicity) and clinical subgroups, including vaccination status, with an adjusted odds ratio of 0.44 (95% CI, 0.25-0.77) in the group with full vaccination and an adjusted odds ratio of 0.49 (95% CI, 0.39-0.62) in the group without full vaccination, according to researchers.

Notably, patients at a greater risk for being admitted to the hospital at baseline had a higher absolute treatment effect. The numbers needed to treat to prevent one hospitalization were 24 vs. 81 in patients with vs. without full COVID vaccination, and 17 vs. 88 in those with multiple vs. without any comorbidities.

“When access to mAbs is limited, prioritizing patients at highest risk for hospitalization has the most potential to reduce health system strain during the COVID-19 pandemic,” Wynia and colleagues wrote.