Test identifies ovarian cancer patients with hyperactive c-Met and ErbB signaling tumors who may benefit from c-Met and pan-HER combination therapy.

Abstract

e18038 Background: No sub-groups of ovarian cancer patients with clinically actionable ErbB genetic variants have yet been found. Measurement of ErbB signaling activity rather than genetic variants may identify ovarian cancer patients likely to benefit from ErbB targeted therapies. We have previously reported studies detecting dysregulated ErbB and c-Met signaling activity in 20%-25% of HER2-negative breast cancer patient tumors using the CELx Signaling Function Test. To determine whether ErbB or c-Met signaling dysregulation is involved in ovarian cancer, the CELx Test was adapted to analyze ovarian tumor cells. The current study set out to: 1) characterize c-Met and ErbB family signaling activity in ovarian patient tumor cells and tumor cell lines; 2) evaluate in vivo response to pan-HER and c-Met inhibitors in an ovarian tumor xenograft model. Methods: For the ex vivo studies, a set of fresh tumor specimens from 15 ovarian cancer patients and a set of 12 ovarian cancer cell lines was obtained. Cell samples were cultured from each. Live cell response to ErbB and c-Met agonists (NRG1b, EGF, or HGF) with or without an antagonist (2C4, a HER2 dimerization inhibitor or tepotinib, a c-Met kinase inhibitor) was measured using an xCELLigence impedance biosensor (Agilent Technologies). Signaling activity above a previously established cut-off value was used to identify abnormal levels of EGFR, HER2 and c-Met signaling activity. For the xenograft study, OVCAR-4, an ovarian cancer cell line, determined to have abnormal HER2, EGFR, and c-Met signaling with the CELx Test, was studied. 40 female NSG mice were each injected with two million cells. Mice were randomly assigned to either a control group or a treatment group that received neratinib, tepotinib, or neratinib and tepotinib for 16 days. Results: Of the patient cell and cell lines samples tested ex vivo with the CELx Test, 4 of 27 (15%; 95% CI = 6%-32%) had hyperactive HER2 and c-Met signaling pathways. In the xenograft study, tumor volume change was 40% less in the tepotinib + neratinib treated group than in the control arm change. There was no significant difference in tumor volume between the control and tepotinib or neratinib groups. Conclusions: These findings suggest that a significant sub-group of ovarian cancer patients have abnormal ErbB and c-Met signaling activity that may respond to treatment with a combination of ErbB and c-Met inhibitors. A clinical trial to evaluate treatment response of this patient sub-set to combined c-Met and pan-HER inhibitors is warranted.