Reversing resistance to a B-Raf inhibitor for the treatment of a proliferative disease by obtaining a tumor sample from the patient and testing it for genetic alterations in a panel of genes comprising BRAF, CRAF, CCND1, CDK4, HER2, IGF-1R, cMET, FGFR1, FGFR2, FGFR3 EGFR, MAP2K1, MAP2K2, NRAS, KRAS HRAS, PTEN, PIK3CA, and P16 and administering a drug combination therapy comprising the B-Raf inhibitor and a second inhibitor which overcomes resistance to the B-Raf inhibitor, which second inhibitor is selected based on genetic alterations discovered in the tumor sample.本發明提供一種藉由如下方法逆轉對用於治療增生性疾病之B-Raf抑制劑的抗性的方法:自患者獲得腫瘤樣品且測試其包含BRAF、CRAF、CCND1、CDK4、HER2、IGF-1R、cMET、FGFR1、FGFR2、FGFR3 EGFR、MAP2K1、MAP2K2、NRAS、KRAS HRAS、PTEN、PIK3CA及P16之一組基因的遺傳變化,及投與包含B-Raf抑制劑及第二抑制劑之藥物組合療法而克服對B-Raf抑制劑之抗性,該第二抑制劑基於腫瘤樣品中所發現之遺傳變化選擇。