Impact of bevacizumab in combination with erlotinib on EGFR-mutated non-small cell lung cancer xenograft models with T790M mutation or MET amplification.

Erlotinib (ERL), an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, shows notable efficacy against non-small cell lung cancer (NSCLC) harboring EGFR mutations. Bevacizumab (BEV), a humanized monoclonal antibody to vascular endothelial cell growth factor (VEGF), in combination with ERL (BEV+ERL) significantly extended progression-free survival in patients with EGFR-mutated NSCLC compared with ERL alone. However, the efficacy of BEV+ERL against EGFR-mutated NSCLC harboring T790M mutation or MET amplification, is unclear. Here, we examined the antitumor activity of BEV+ERL in four xenograft models of EGFR-mutated NSCLC (three harboring ERL resistance mutations). In the HCC827 models (exon 19 deletion: DEL), ERL significantly inhibited tumor growth by blocking EGFR signal transduction. Although there was no difference between ERL and BEV+ERL in maximum tumor growth inhibition, BEV+ERL significantly suppressed tumor regrowth during a drug-cessation period. In the HCC827-EPR model (DEL+T790M) and HCC827-vTR model (DEL+MET amplification), ERL reduced EGFR signal transduction and showed less pronounced but still significant tumor growth inhibition than in the HCC827 model. In these models, tumor growth inhibition was significantly stronger with BEV+ERL than with each single agent. In the NCI-H1975 model (L858R+T790M), ERL did not inhibit growth or EGFR signal transduction, and BEV+ERL did not inhibit growth more than BEV. BEV alone significantly decreased microvessel density in each tumor. In conclusion, addition of BEV to ERL did not enhance antitumor activity in primarily ERL-resistant tumors with T790M mutation; however, BEV+ERL enhanced antitumor activity in T790M mutation- or MET amplification-positive tumors as long as their growth remained significantly suppressed by ERL.

Furugaki K ，Fukumura J ，Iwai T ，Yorozu K ，Kurasawa M ，Yanagisawa M ，Moriya Y ，Yamamoto K ，Suda K ，Mizuuchi H ，Mitsudomi T ，Harada N ... -  《-》

Addition of S-1 to the epidermal growth factor receptor inhibitor gefitinib overcomes gefitinib resistance in non-small cell lung cancer cell lines with MET amplification.

Okabe T ，Okamoto I ，Tsukioka S ，Uchida J ，Hatashita E ，Yamada Y ，Yoshida T ，Nishio K ，Fukuoka M ，Jänne PA ，Nakagawa K ... -  《CLINICAL CANCER RESEARCH》

Bevacizumab counteracts VEGF-dependent resistance to erlotinib in an EGFR-mutated NSCLC xenograft model.

Masuda C ，Yanagisawa M ，Yorozu K ，Kurasawa M ，Furugaki K ，Ishikura N ，Iwai T ，Sugimoto M ，Yamamoto K ... -  《-》

Inhibition of β-Catenin enhances the anticancer effect of irreversible EGFR-TKI in EGFR-mutated non-small-cell lung cancer with a T790M mutation.

Togashi Y ，Hayashi H ，Terashima M ，de Velasco MA ，Sakai K ，Fujita Y ，Tomida S ，Nakagawa K ，Nishio K ... -  《-》

Antitumor activity of HM781-36B, a highly effective pan-HER inhibitor in erlotinib-resistant NSCLC and other EGFR-dependent cancer models.

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases has been implicated in a variety of cancers. In particular, activating mutations such as the L858R point mutation in exon 21 and the small in-frame deletions in exon 19 of the EGFR tyrosine kinase domain are correlated with sensitivity to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC) patients. Clinical treatment of patients is limited by the development of drug resistance resulting mainly from a gatekeeper mutation (T790M). In this study, we evaluated the therapeutic potential of a novel, irreversible pan-HER inhibitor, HM781-36B. The results from this study show that HM781-36B is a potent inhibitor of EGFR in vitro, including the EGFR-acquired resistance mutation (T790M), as well as HER-2 and HER-4, compared with other EGFR tyrosine kinases inhibitors (erlotinib, lapatinib and BIBW2992). HM781-36B treatment of EGFR DelE746_A750-harboring erlotinib-sensitive HCC827 and EGFR L858R/T790M-harboring erlotinib-resistant NCI-H1975 NSCLC cells results in the inhibition of EGFR phosphorylation and the subsequent deactivation of downstream signaling proteins. Additionally, HM781-36B shows an excellent efficacy in a variety of EGFR- and HER-2-dependent tumor xenograft models, including erlotinib-sensitive HCC827 NSCLC cells, erlotinib-resistant NCI-H1975 NSCLC cells, HER-2 overexpressing Calu-3 NSCLC cells, NCI-N87 gastric cancer cells, SK-Ov3 ovarian cancer cells and EGFR-overexpressing A431 epidermoid carcinoma cancer cells. On the basis of these preclinical results, HM781-36B is the most potent pan-HER inhibitor, which will be advantageous for the treatment of patients with NSCLC including clinical limitation caused by acquired mutation (EGFR T790M), breast cancer and gastric cancer.

Cha MY ，Lee KO ，Kim M ，Song JY ，Lee KH ，Park J ，Chae YJ ，Kim YH ，Suh KH ，Lee GS ，Park SB ，Kim MS ... -  《-》