Combinations of Brutons tyrosine kinase (Btk) inhibitors, e.g., 1-((R)-3-(4-amino-3-(4-phenoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl)piperidin-1-yl)prop-2-en-1-one, with CYP3A4 inhibitors are provided. Also provided are methods of treating cancers, and autoimmune disorders by administering combinations of Brutons tyrosine kinase (Btk) inhibitors, e.g., 1-4((R)-3-(4-amino-3-(4-phenoxyphenyl)-1 H-pyrazolo[3, 4-d]pyrimidin-1-yl)piperidin-1-yl)prop-2-en-1-one, and CYP3A4 inhibitors.