The invention is directed to a pharmaceutical combination composition comprising stable complexes with controlled particle size, increased apparent solubility and increased dissolution rate comprising as active compound Ivacaftor and Lumacaftor, their salts, or derivatives thereof, which is useful in the treatment of cystic fibrosis transmembrane conductance regulator (CFTR) mediated disease. More specifically, the pharmaceutical composition comprising the complexes of the present invention possess instantaneous redispersibility, increased apparent solubility and permeability, no observable food effect which deliver the opportunity of precise dosing and ease of administration of the reconstituted complex in solution form. The invention also relates to methods of formulating and manufacturing complexes according to the invention, pharmaceutical compositions containing it, its uses and methods of treatment using the complex and its compositions.