There is provided inter alia a dry powder pharmaceutical formulation for inhalation comprising: (i) 6-(2-((4-amino-3-(3-hydroxyphenyl)-1 H-pyrazolo[3,4-d]pyrimidin-1-yl) methyl)-3- (2-chlorobenzyl)-4-oxo-3,4-dihydroquinazolin-5-yl)-N, N-bis(2-methoxyethyl)hex-5- ynamide or a pharmaceutically acceptable salt thereof, including all stereoisomers, tautomers and isotopic derivatives thereof and solvates thereof in particulate form as active ingredient； (ii) particulate lactose as carrier； and (iii) a particulate stabilizing agent selected from metal salts of stearic acid such as magnesium stearate and metal salts of stearyl fumarate.
