Despite therapeutic advances against SARS-CoV-2, including multiple vaccines, oral antiviral therapies, and monoclonal antibodies, patients with hematologic malignancies remain at increased risk for complications secondary to SARS-CoV-2 (Vijenthira et al., 2020). Before vaccines for SARS-CoV-2 were available. a metaanalysis of over 3,300 patients with hematologic malignancies and COVID-19 showed a 34% risk of death (Vijenthira et al., 2020). Even with vaccination, mortality is over 10%, and recent reports have demonstrated increased risk of SARS-CoV-2 infection, hospitalization, and death secondary to COVID-19 in vaccinated patients with hematologic malignancies, especially in those receiving B cell depleting therapy (Pagano et al., 2022). Accordingly, pre-exposure prophylaxis is a critical component in the care of patients with hematologic malignancies. In the United States, the combined monoclonal product AZD7442/Evusheld (tixagevimab-cilgavimab) has been granted emergency use authorization (EUA) in individuals 12 years and older who have a moderate to severe immunocompromising condition and may not mount an adequate vaccination response (https://www. fda. gov/media/154701/download). Authorization stems from a recently published randomized, placebo-controlled trial (PROVENT, NCT04625725) of over 5,000 adults who had not received

SARS-CoV-2 vaccination at the time of AZD7442 administration (Levin et al., 2022). Patients randomized to the treatment arm received a single dose (150 mg of tixagevimab and 150 mg of cilgavimab). With a median follow-up at 83 days, receipt of AZD7442 resulted in a 77% reduction in symptomatic COVID-19 (p< 0.001, 95% confidence interval [CI] 46–90) and a 69% reduction in symptomatic COVID-19 or death from any cause (p= 0.002, 95% CI 36–85). Notably, this trial was conducted before the emergence of the Omicron variant (B. 1.1. 529 lineage) of SARS-CoV-2 in late 2021. In addition, although PROVENT included patients who were at risk for inadequate vaccine response, only 7% of participants had cancer or a history of cancer. We therefore evaluated the efficacy of AZD7442 in patients who had hematologic malignancies and who had been treated at Memorial Sloan Kettering Cancer Center (MSKCC), and our evaluation included measurement of anti-SARS-CoV-2 spike protein antibody titers and plasma neutralizing activity against the Omicron variant after AZD7442 administration.