The invention relates generally to pharmaceutical tablet compositions comprising fumaric acid and the compound (S)-2-(3′-(hydroxymethyl)-1-methyl-5-((5-(2-methyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-yl)amino)-6-oxo-1,6-dihydro-[3,4′-bipyridin]-2′-yl)-7,7-dimethyl-2,3,4,6,7,8-hexahydro-1H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-1-one free base that is an inhibitor of Bruton's tyrosine kinase. The invention further relates to amorphous solid dispersions comprising at least one polymer and the Bruton's kinase inhibitor free base compound. The invention further relates to crystalline mesylate salts, crystalline chloride salts and crystalline sulfate salts of the Bruton's kinase inhibitor free base compound. In some aspects, the crystalline salts are single polymorphs.
