Abstract
Ofatumumab is the first fully human anti-CD20 monoclonal antibody that, on March 26, 2021, was approved by the EMA to treat patients with relapsing multiple sclerosis. This paper aimed to present a case confirming the ability to produce and maintain anti-SARS-CoV-2 antibodies in a patient treated with ofatumumab for over 4 years. The course of the infection was moderate, and the patient did not require hospitalization. Antibody measurements were performed five times post-COVID-19 infection. The first test was performed in the fourth month (131 days), and the last, over 1 year after the infection. To date, only 2 cases have been published describing the ability of a patient treated with the same drug to produce antibodies against SARS-CoV-2, although the observation was conducted over a shorter period. In our case study, we have 15-month follow-up data. The patient was not vaccinated and additionally received suppressive steroid therapy due to the relapse. We observed an increase in antibodies up to 10 months from the infection. The case under analysis suggests that patients treated with ofatumumab, despite complete peripheral B-cell depletion, can produce and maintain a long-lasting immune response.