The Evolving Treatment Landscape in BRAF-V600E-Mutated Metastatic Colorectal Cancer

Am Soc Clin Oncol Educ Book. 2022 Apr:42:1-10. doi: 10.1200/EDBK_349561.

Abstract

Between 8% and 12% of patients with metastatic colorectal cancer (mCRC) harbor a BRAF-V600E mutation in their tumors, which is associated with a poor response to standard chemotherapy and short overall survival. Moreover, nearly 30% of BRAF-V600E mCRC tumors also have microsatellite instability. Transcriptomic signatures suggest a strong immunogenic biologic background for most of these tumors. In contrast to the melanoma context, single-agent BRAF inhibition does not achieve clinical benefit in BRAF-V600E mCRC. Different preclinical/translational studies have elucidated that, in this context, upon BRAF inhibition, there is immediate signal upregulation via the EGFR, and therefore an anti-EGFR treatment should be added to the BRAF inhibitor. Several phase II studies have confirmed the activity of BRAF inhibitors combined with EGFR-directed monoclonal antibodies in patients with BRAF-V600E mCRC. The role of other mitogen-activated protein kinase inhibitors, such as mitogen-activated protein kinase kinase or PI3K inhibitors, remains unclear. The phase III BEACON clinical trial confirmed the BRAF/EGFR inhibitor combination of encorafenib/cetuximab as the new standard of care for BRAF-V600E mCRC after at least one previous line of systemic therapy. Novel approaches for managing BRAF-V600E mCRC include, among others, triple combinations of BRAF inhibitors and anti-EGFR antibodies combined with immune checkpoint inhibitors in the microsatellite instability population and evaluation of the encorafenib/cetuximab treatment in combination with standard chemotherapy with bevacizumab in the first-line setting.

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols*
  • Cetuximab / genetics
  • Cetuximab / therapeutic use
  • Colorectal Neoplasms* / drug therapy
  • Colorectal Neoplasms* / genetics
  • Colorectal Neoplasms* / pathology
  • ErbB Receptors / genetics
  • Humans
  • Microsatellite Instability
  • Mutation
  • Phosphatidylinositol 3-Kinases / genetics
  • Proto-Oncogene Proteins B-raf / genetics

Substances

  • ErbB Receptors
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Cetuximab