Provided are a pharmaceutical composition which enhances the sensitivity of a cancer to a molecular target drug, such as gefitinib and erlotinib, wherein the cancer has resistance to the molecular target drug, and a cancer therapeutic agent effective against a cancer having resistance to a molecular target drug, such as gefitinib and erlotinib. The pharmaceutical composition comprising an HGF-MET receptor pathway inhibitor enhances the sensitivity of a cancer to a molecular target drug, such as ...

The invention features a method for treating patients who have an EGFR-driven cancer, which is, or has become, refractory to a tyrosine kinase inhibitor, such as eriotinib and gefitinib, by administering a compound of formula (I) to the patient. The invention also features treating EGFR-driven cancers having an EGFR mutation identified herein.

This invention relates to a method of preparing gefitinib and an intermediate used therein. In the method of preparing gefitinib, the production of an N-alkylated impurity can be suppressed via a simple process, and thus, gefitinib having high purity can be obtained with high efficiency without a complicated separation process such as chromatography, thereby enabling the effective mass production of gefitinib.