Anti-MEK and Anti-EGFR mAbs in RAS-Mutant Metastatic Colorectal Cancer: Case Series and Rationale

Adv Ther. 2019 Jun;36(6):1480-1484. doi: 10.1007/s12325-019-00949-y. Epub 2019 Apr 12.

Abstract

KRAS (Kirsten rat sarcoma viral oncogene) or BRAF (v-raf murine sarcoma viral oncogene homolog B1) constitutive activation leads to anti-EGFR (epidermal growth factor receptor) therapy resistance of metastatic colorectal cancer patients. In this article we investigate the effects of anti-MEK (mitogen-activated protein kinase) antibody (trametinib) combined with anti-EGFR (cetuximab) on colon cancer cell lines with different RAS statuses. Even though cetuximab has no effect on RAS cell viability and ERK (extracellular-signal-regulated kinase) phosphorylation (one of the last kinases of the EGFR pathway), trametinib can induce cell death and inhibit the activation of ERK alone or in combination with cetuximab. In a more pathologic context, we observed that KRAS colon cancer patient biopsies treated ex vivo with trametinib and cetuximab also present less ERK phosphorylation. Finally, nine ovarian, endometrial and colon cancer patients with different KRAS statuses were treated with anti-EGFR/anti-MEK combination off label after molecular tumor board decision. KRAS exon 2 patients have significantly longer PFS (progression-free survival) than with previous lines of treatments. We believe that such observations provide a rationale for designing a clinical trial to test this association in RAS exon 2 mutated cancers.

Keywords: Cetuximab; EGFR; KRAS; MEK; Trametinib.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Antineoplastic Agents / therapeutic use
  • Cetuximab / therapeutic use*
  • Colorectal Neoplasms / drug therapy*
  • ErbB Receptors / antagonists & inhibitors*
  • Female
  • Humans
  • Male
  • Mice
  • Middle Aged
  • Mitogen-Activated Protein Kinases / antagonists & inhibitors*
  • Neoplasm Metastasis / drug therapy
  • Proto-Oncogene Proteins B-raf / drug effects*
  • Pyridones / therapeutic use*
  • Pyrimidinones / therapeutic use*
  • Rats

Substances

  • Antineoplastic Agents
  • Pyridones
  • Pyrimidinones
  • ErbB Receptors
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Mitogen-Activated Protein Kinases
  • Cetuximab