On the other hand, the BTK inhibitor ibrutinib is currently FDA-approved for the treatment of B cell cancers and the chronic graft-versus-host disease34 while ongoing clinical trials evaluate the use of BTK inhibitors in autoimmune diseases, such as multiple sclerosis (ClinicalTrials.gov Identifier: NCT02975349) and rheumatoid arthritis (ClinicalTrials.gov Identifier: NCT03233230). The gene discussed is BTK; the disease is rheumatoid arthritis.