An orally bioavailable ditosilate salt form of selatinib, an analog of the quinazoline lapatinib and dual inhibitor of epidermal growth factor receptor (EGFR) and Human Epidermal Growth Factor Receptor 2 (ErbB-2 or HER-2), with potential antineoplastic activity. Upon administration, selatinib reversibly blocks phosphorylation of both EGFR and ErbB2, thereby suppressing tumor growth in EGFR/ErbB-2-overexpressing tumor cells. The tyrosine kinases EGFR and ErbB2 have been implicated in the growth of various tumor types.