BTK and plasma cell myeloma: Acalabrutinib inhibited BTK with an IC50 of 3 nM and had less off-target activity on EGFR, ITK, or TEC;285 zanubrutinib had similar inhibitory activity to ibrutinib against BTK, but its IC50s on TEC, ITK, EGFR, HER2, and JAK3 were 2–70 times higher than those of ibrutinib.286 Currently, the FDA has approved them for the treatment of adult MCL patients who have received at least one prior therapy.287 Both of them are still evaluated in the clinic for the treatment of some other malignancies, such as NHL,288 multiple myeloma (MM),289 and ovarian cancer.290