Plasma cell targeting by the anti-CD38 antibody daratumumab in ME/CFS

Prof Øystein Fluge discussed his research group's current work on daratumumab, a monoclonal antibody that binds to the glycoprotein CD38 of (long-lived) plasma cells and is also used in chemotherapy. Prof. Fluge presented data from initial pilot studies using daratumumab in ME/CFS patients to reduce plasma cells that produce IgG. In the pilot studies, six patients received four injections, and four patients received prolonged therapy with a total of seven injections. Of the ten patients, six showed a positive response, while daratumumab showed no significant effect in the remaining four patients, with an overall mild side effect profile. In the subgroup that did show an effect, IgG levels decreased, functional status improved, ME/CFS symptoms reduced, and some patients were able to walk more than 10,000 steps per day. The effect began earlier than in previous rituximab studies, after approximately 6-8 weeks. In 50% of study participants, the effect of the therapy was maintained throughout the observation period (15-24 months). Furthermore, it was shown that those who did not respond to the therapy had a significantly lower number of natural killer cells than the subgroup that did. The next step is to conduct a randomised, placebo-controlled phase II trial with 66 patients.