Bamlanivimab Treatment Leads to Rapid Selection of Immune Escape Variant Carrying the E484K Mutation in a B.1.1.7-Infected and Immunosuppressed Patient

Abstract

To the Editor—Kumar et al [1] reported on the role of single bamlanivimab in preventing hospitalization associated with coronavirus disease 2019 (COVID-19). There is scarce evidence of prevalence of emergent variants in patients treated with bamlanivimab [2]. But very little is known about treatment-emergent variants in the B.1.1.7 lineage, which is by now the dominant strain throughout Europe and North America. We hereby report the selection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune escape mutations in a B.1.1.7 variant 7 days after administration of single bamlanivimab in a patient with deeply impaired cellular immunity (Figure 1). The patient newly diagnosed with acute myeloid leukemia first tested positive for SARS-CoV-2 at day 11 after the start of chemotherapy. Initially, the cycle threshold (Ct) was above 30 and melting point analysis at day 15 suggested B.1.1.7 as the causative agent of this...