GDC-0853 is an orally bioavailable, selective, and reversible Bruton’s tyrosine kinase (BTK) inhibitor with IC50s ranging from 2-9 nM for basophil activation, B cell receptor activation, and constitutive p-BTK activity in whole blood lysates. In rats, treatment for longer than 7 days leads to pancreatic toxicity but it does not occur in mice or dogs, even at higher doses. Formulations containing GDC-0853 were well-tolerated in Phase I clinical trials and are in additional clinical trials for rheumatoid arthritis, lupus erythematosus, lymphoma, and leukemia.