How BTK Degradation Differs from Inhibition

Dr Shadman explains how BTK degradation differs mechanistically from BTK inhibition. Bruton tyrosine kinase is a central enzyme and protein in the pathophysiology of B-cell malignancies, including Waldenström macroglobulinemia and chronic lymphocytic leukemia. Covalent and non-covalent inhibitors, ibrutinib, acalabrutinib, zanubrutinib, and pirtobrutinib, block the enzyme's catalytic activity, but resistance frequently arises through mutations that impair drug binding. Degraders such as catadegbrutinib instead recruit cellular machinery to remove the entire BTK protein, addressing its scaffold function beyond enzymatic activity, and remain active even in patients who progress on prior BTK inhibitors. Dr Shadman emphasizes this is a genuinely distinct strategy rather than another form of inhibition, with a favorable safety profile that could support movement into earlier lines of therapy given the high safety standards in low-grade lymphomas. He adds that the heavily pretreated CaDAnCe-101 population mirrors the patients seen in clinic who have exhausted prior options and still require novel mechanisms of action.