Thus, we tested the efficacy of these irreversible inhibitors CL-387785 and WZ-4002 (Figure S3) on lapatinib-resistant ERBB2 point mutations (L755S, L755P and T798M). Interestingly, both inhibitors potently inhibited proliferation of Ba/F3-ERBB2 mutant cell lines with IC50 values less than 200 nM (Figure 7A and 7B). WZ-4002 was more potent (fold-increase of IC50 of mutant ERBB2 compared to wild type ERBB2) than CL-387785 (Table S2).