Drugs of interest to pathologists
Drugs related to surgical pathology
Vemurafenib

Author: Him G. Kwee, M.D. (see Authors page)

Revised: 11 December 2017, last major update October 2011

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Vemurafenib [title] review [ptyp]

Cite this page: Kwee, H.G. Vemurafenib. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/drugsvemurafenib.html. Accessed August 16th, 2018.
Definition / general
  • Vemurafenib is a BRAF protein kinase inhibitor
  • BRAF means v-raf murine sarcoma viral oncogene homolog B1; is a serine / threonine specific protein kinase encoded by the BRAF gene that is a part of the RAS/MAPK pathway regulating the growth, maturation, proliferation, survival and apoptosis of cells
  • Vemurafenib interrupts the BRAF/MEK step in the BRAF/MEK/ERK pathway if the BRAF has the V600E mutation (valine replaced by glutamic acid)
  • If no V600E mutation, vemurafenib could stimulate BRAF and may promote tumor growth (N Engl J Med 2010;363:809)
Trade name
  • Zelboraf®
Clinical information
  • Approved by U.S. Food and Drug Administration in August 2011 for unresectable or metastatic malignant melanoma that has the BRAF V600E mutation
  • Approximate cost: $10,000 per month in 2011
Uses by pathologists
  • 50% of melanomas have V600E mutation; cannot predict by histology
  • On the same day that the FDA approved the drug, it also approved the test to diagnose this mutation, the Cobas 4800 BRAF V600 mutation test (Roche: cobas┬« 4800 BRAF V600 Mutation Test [Accessed 6 December 2017]), which can be performed on formalin fixed paraffin embedded tissue (FDA News Release, August 17, 2011)
  • Side effect of vemurafenib is that 24% of patients develop cutaneous squamous cell carcinoma; may also develop keratoacanthomas and squamous papillomas (Genentech: Highlights Of Prescribing Information for Zelboraf [Accessed 6 December 2017] and Genentech: Zelboraf┬« (vemurafenib) [Accessed 6 December 2017])
  • Drug cost is comparable to ipilimumab, another FDA approved drug for melanoma (March 2011), which is a human monoclonal antibody that binds CTLA-4 (cytotoxic T lymphocyte associated antigen 4); however, ipilimumab could cause severe and potentially fatal immune mediated enterocolitis, hepatitis and dermatitis (FDA News Release, March 2011)
  • Combination therapy with ipilimumab and vemurafenib is being studied in a clinical trial (Roche clinical bulletin, June 2011)
  • There are ongoing clinical trials to study the efficacy of vemurafenib in advanced colorectal carcinoma and papillary thyroid carcinoma