Combining BRAF/MEK Inhibitors with Immunotherapy in the Treatment of Metastatic Melanoma

Am J Clin Dermatol. 2021 May;22(3):301-314. doi: 10.1007/s40257-021-00593-9. Epub 2021 Mar 25.

Abstract

The management and prognosis of BRAF-mutant metastatic melanoma have changed drastically following the introduction of immune checkpoint inhibitors and molecularly targeted agents. These treatment options present different mechanisms of action and toxicities but also totally distinct kinetics of their response, including a "relatively" short-lasting benefit in subsets of patients treated with BRAF/MEK inhibitors and a lower response rate in patients treated with immune checkpoint inhibitors. BRAF/MEK inhibitors, when administered prior to or concurrently with immune checkpoint inhibitors, at least transiently alter some immunosuppressive parameters of the tumor microenvironment and theoretically improve sensitivity to immunotherapy. Preclinical data from mouse models with oncogene-addicted melanoma confirmed this beneficial immune/targeted synergy and supported the clinical testing of combinations of BRAF/MEK inhibitors and immune checkpoint inhibitors to improve the activity of upfront anti-melanoma therapies. The first positive phase III results were published in 2020, and triggered the discussion about the benefits, the limitations, as well as the possible implications of combining or sequencing targeted therapies with immune checkpoint inhibitors in everyday practice. Beginning from the interplay of immune/targeted agents within the melanoma microenvironment, this review outlines available information from the retrospective experience up to the late-stage randomized evidence on combinatorial treatments. Many clinical trials are currently underway exploring open questions about optimal timing, new immune biomarkers, and eligible patient subsets for these immune/targeted regimens. Awaiting these results, decision making in the first-line setting for BRAF-mutant melanoma is still guided by the patients' characteristics and the biological aspects of melanoma.

Publication types

  • Review

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Clinical Decision-Making
  • Clinical Trials as Topic
  • Humans
  • Immune Checkpoint Inhibitors / pharmacology
  • Immune Checkpoint Inhibitors / therapeutic use*
  • Melanoma / drug therapy*
  • Melanoma / genetics
  • Melanoma / immunology
  • Melanoma / secondary
  • Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
  • Molecular Targeted Therapy / methods
  • Mutation
  • Patient Selection
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Proto-Oncogene Proteins B-raf / antagonists & inhibitors
  • Proto-Oncogene Proteins B-raf / genetics
  • Skin Neoplasms / drug therapy*
  • Skin Neoplasms / genetics
  • Skin Neoplasms / microbiology
  • Skin Neoplasms / pathology
  • Treatment Outcome
  • Tumor Microenvironment / drug effects
  • Tumor Microenvironment / genetics
  • Tumor Microenvironment / immunology

Substances

  • Immune Checkpoint Inhibitors
  • Protein Kinase Inhibitors
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Mitogen-Activated Protein Kinase Kinases