Outpatient anti-spike monoclonal antibody administration is associated with decreased morbidity and mortality among patients with cancer and COVID-19.

Patients with cancer have many comorbidities that increase their risk of death from Coronavirus disease 2019 (COVID-19). Anti-spike monoclonal antibodies (mAbs) reduce the risk of hospitalization or death from COVID-19 in the general population. To our knowledge, no studies have focused on the clinical efficacy of mAbs compared to no outpatient treatment exclusively among patients with solid tumors and hematologic malignancies, who are often excluded from clinical trials. We studied patients with cancer who had COVID-19 between 11.9.2020 and 7.21.2022 and received mAbs in an outpatient setting. We compared hospitalization and mortality rates to those of patients with cancer concurrently diagnosed with COVID-19, who were eligible for mAbs, but did not receive any outpatient treatment. 63 patients received mAbs and 89 no outpatient treatment. Administration of mAbs was associated with lower 90-day hospitalization (20.6% vs. 60.7%, p <0.001), all-cause (6.3% vs. 19.1%, p 0.025) and COVID-19-attributed (3.2% vs. 14.6%, p 0.019) mortality rates, and lower peak O requirements (ordinal Odds Ratio [OR] = 0.33, 95% Confidence Intervals [CI] = 0.20-0.53). Administration of mAbs (aHR 0.21, p <0.001), age (≥ 60 years, adjusted Hazard Ratio [aHR] 1.86, p=0.033), and metastases (aHR 0.41, p 0.007) were independently associated with hospitalization. mAb treatment remained significantly associated with all-cause (aHR 0.27, p 0.019) and COVID-19-attributed (aHR 0.19, p 0.031) mortality, after adjustment for other factors. mAb administration was associated with improved clinical outcomes among vulnerable patients with cancer and COVID-19. With no mAbs approved currently for treatment against the prevalent circulating variants, the development of new mAbs should be a research priority.