BTK and lupus nephritis: For example, the covalent BTK inhibitor zanubrutinib, which is approved by the FDA for use in Waldenström’s macroglobulinemia, mantle cell lymphoma, and marginal zone lymphoma, announced the initiation of clinical trials to test its efficacy in active proliferative lupus nephritis late in 2020, anticipating study completion in August of 2023 (clinicaltrials.gov identifier NCT04643470).