Casirivimab-imdevimab monoclonal antibody treatment for an immunocompromised patient with persistent SARS-CoV-2 infection: a case report

Background: Persistent acute SARS-CoV- 2 infection is characterised by the persistence of symptoms of a COVID-19 illness and a persistently positive SARS-CoV-2 RT PCR result. It is often seen in immunocompromised individuals. Currently, there are no approved treatment regimens or guidelines for management. Methods: Our patient is a middle-aged male who had received chemotherapy prior to the onset of his SARS- CoV-2 infection and subsequently was diagnosed with a persistent and acute SARS- CoV-2 infection after presenting to us with a pyrexia of unknown origin. He was treated on an off-label basis following informed consent with casirivimab-imdevimab monoclonal antibody therapy, comprising two IgG1 neutralising human monoclonal antibodies at a dose of 600 mg each. Results: Our patient had significant clinical improvement on treatment with the monoclonal antibody therapy and it was well tolerated without any adverse effects. He is currently doing well during follow up. Conclusions: Casirivimab-imdevimab monoclonal antibody therapy could be beneficial for people with persistent acute SARS-CoV-2 infection. Therapy is warranted on a case-to-case basis. This highlights the need to identify immunocompromised individuals who are at risk of developing persistent acute SARS-CoV-2 infection to enable their prompt treatment.