Ensitrelvir eradicates persistent SARS-CoV-2 infection in a follicular lymphoma patient treated with anti-CD20 antibodies

Patients with hematological malignancies, especially B-cell malignancies, who received anti-CD20 antibodies exhibit a poor immune response to the mRNA coronavirus disease 2019 (COVID-19) vaccine within 6–12 months after the last administration. These patients occasionally present with severe COVID-19 symptoms. Additionally, patients with hematologic diseases who have persistent COVID-19 after receiving anti-CD20 antibodies, postpone chemotherapy for the primary disease. Despite the efficacy of ensitrelvir in shortening the duration of symptoms, evidence of improved prognosis is lacking. However, prognosis might be improved if ensitrelvir treatment could reduce the viral load and shorten the time to postpone chemotherapy. It is unclear whether viral reduction directly improves prognosis. However, faster viral reduction may lead to faster resumption of chemotherapy for the underlying disease, resulting in better prognosis. Here, we present a case wherein we administered ensitrelvir fumaric acid to a 75-year-old woman with persistent COVID-19 after anti-CD20 antibody treatment. Her symptoms resolved quickly, with a reduction of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load, and she could continue receiving chemotherapy for lymphoma. Our findings suggest that ensitrelvir administration should be considered in patients with SARS-CoV-2 infection after anti-CD20 antibody treatment.