Tepotinib plus cetuximab in patients (pts) with RAS/BRAF wild-type left-sided metastatic colorectal cancer (mCRC) and acquired resistance to anti-EGFR antibody therapy due to MET amplification (METamp).

Abstract

TPS149 Background: METamp is a secondary, or co-driving, genetic change in pts with mCRC and acquired resistance to anti-EGFR therapy, which can contribute to disease progression. In EGFR-resistant pts with mCRC and METamp, MET inhibition + an anti-EGFR agent could achieve disease control by targeting emerging MET pathway activation and maintaining EGFR pathway inhibition. Tepotinib is an oral, once-daily, highly selective, potent MET tyrosine kinase inhibitor (TKI). Tepotinib + the EGFR TKI gefitinib demonstrated improved outcomes in pts with EGFR-mutant METamp non-small cell lung cancer and acquired EGFR TKI resistance vs chemotherapy (INSIGHT: NCT01982955). In these pts, progression-free survival (PFS) was 16.6 vs 4.2 months (HR = 0.13; 90% CI: 0.04, 0.43) and overall survival (OS) was 37.3 vs 13.1 months (HR = 0.08; 90% CI: 0.01, 0.51). In pts with mCRC and acquired resistance to anti-EGFR antibody therapy due to METamp, tepotinib + anti-EGFR antibody cetuximab may be active and therefore provide an effective therapeutic option. Methods: This Phase II, multicenter, single-arm, open-label study will assess preliminary antitumor activity, safety and tolerability, and explore pharmacokinetic (PK) profiles of tepotinib + cetuximab in pts with RAS/BRAF wild-type left-sided mCRC and acquired resistance to anti-EGFR antibody-targeted therapy due to METamp. A safety run-in (6-12 pts) will evaluate the recommended Phase II dose of tepotinib to be used in combination with cetuximab (endpoint:dose-limiting toxicities). Enrollment is based on a confirmed advanced left-sided CRC diagnosis, with RAS/BRAF wild-type, documented previous anti-EGFR therapy and acquired resistance on the most recent anti-EGFR antibody and METamp confirmed by liquid and/or tissue biopsy. Pts must be ≥18 years old and have an Eastern Cooperative Oncology Group performance status of 0/1 and normal organ function. The study will screen sufficient pts to account for setting-specific METamp heterogenicity. Approximately 42 pts are planned to receive study treatment: ~22 in Cohort A (tepotinib second-line, outside US) and 20 in Cohort B (tepotinib ≥third-line, US only). Primary endpoint:investigator-assessed objective response (RECIST 1.1). Secondary endpoints are investigator-assessed duration of response (DoR) and PFS (RECIST 1.1), OS, tolerability and safety (NCI-CTCAE v5.0) and cetuximab immunogenicity (measured by antidrug antibody assays at the start and end of treatment). Additional endpoints include assessment of tepotinib and cetuximab PK profiles and expression of biomarkers of resistance (from blood and/or tissue samples). Retrospective assessment of best overall response, DoR and PFS by an independent review committee may be conducted. No formal statistical hypothesis will be tested in this exploratory study. Clinical trial information: NCT04515394.