592326 Disclosed is the use of an oligomer capable of inhibiting expression of HER3 and optionally one or more of HER2 and EGFR genes consisting of 10 to 50 contiguous monomers wherein adjacent monomers are covalently linked by a phosphate group or a phosphorothioate group, and a protein kinase inhibitor of EGFR (HER1), in combination for the manufacture of a medicament for the treatment of cancer in a mammal.