The Daratumumab Crosses the Blood Brain Barrier

NK/T cell lymphoma is a rare disease in our Western countries counting for less than 1% of all non-Hodgkin lymphomas but is more and more observed due to globalization. The central nervous system (CNS) could be involved in more than 5% of the cases at relapse with a catastrophic median overall survival after diagnosis of 2.53 months. It is an unmet medical need with new therapeutic options needed. Daratumumab is a monoclonal antibody directed against CD38 which the NK cells harbour. Some data suggest an efficacy against of that drug against NK/T cell lymphoma. In order to consider the Daratumumab as a potential therapeutic option in the NK/T cell with CNS involvement, we wanted to assess whether this antibody crosses the blood brain barrier. We assess the presence of the Daratumumab in the cerebrospinal fluid (CSF) at different steps of a patient with CNS involvement of a NK/T cell lymphoma while he was treated with Daratumumab alone. With this goal, we realized a qualitative isoectrofocusing in the blood and the CSF baseline and after every Daratumumab administration. With this method, we couldn't observe any focusing in the blood before the first Daratumumab administration. In the CSF, we could just observe a profile compatible with the neoplastic infiltration. After the first injection of the Daratumumab, which is a monoclonal antibody, we could observe the appearance of a monoclonal band in the blood, becoming more and more obvious as long as the patient received the drug week after week. In the CSF, we could observe more discreetly but obviously the same phenomenon in parallel, witnessing the crossing of the Daratumumab through the intact blood brain barrier. From that observation, we can attest that the Daratumumab is able to cross the blood brain barrier making this drug a very interesting one in the field of the CNS involvement of some malignancies harbouring the CD38 on their surface as the plasma cell leukemia, the multiple myeloma and the NK/T cell lymphoma. Some quantitative data and further evaluations must be done in order to assess the efficacy of the Daratumumab in these indications.