Safety and Efficacy of the Addition of Simvastatin to Cetuximab in Previously Treated KRAS Mutant Metastatic Colorectal Cancer Patients

Invest New Drugs. 2015 Dec;33(6):1242-7. doi: 10.1007/s10637-015-0285-8. Epub 2015 Sep 19.

Abstract

Introduction: Cetuximab is registered for use in colorectal cancer (CRC) patients with RAS wild-type tumours only. Simvastatin blocks the mevalonate pathway and thereby interferes with the post-translational modification (prenylation) of KRAS. We hypothesize that the activated KRAS pathway in KRAS mutant tumors can be inhibited by simvastatin rendering these tumors sensitive to the EGFR inhibitor cetuximab.

Methods: A Simon two-stage, single-arm, phase II study was performed to test the efficacy and safety of the addition of simvastatin to cetuximab in patients with a KRAS mutation in their CRC tumour who were previously treated with fluoropyrimidine, oxaliplatin and irinotecan based regimens. The primary endpoint was to test the percentage of patients alive and free from progression 12.5 weeks after the first administration of cetuximab. Our hypothesis was that at least 40% was free from progression, comparable to, though slightly lower than in KRAS wild-type patients.

Results: Four of 18 included patients (22.2%) were free from progression at the primary endpoint time. The time to progression in these 4 patients ranged from 20.3 to 47 weeks.

Conclusion: Based on the current study we conclude that the theoretical concept of KRAS modulation with simvastatin was not applicable in the clinic, as we were not able to restore sensitivity to cetuximab in CRC patients harbouring a somatic KRAS mutation.

Keywords: Cetuximab; Colorectal cancer; KRAS; Statin.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antineoplastic Combined Chemotherapy Protocols
  • Cetuximab / administration & dosage*
  • Cetuximab / adverse effects
  • Colorectal Neoplasms / diagnosis
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / genetics*
  • Exanthema / chemically induced
  • Fatigue / chemically induced
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mutation / genetics*
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • Simvastatin / administration & dosage*
  • Simvastatin / adverse effects
  • Treatment Outcome

Substances

  • KRAS protein, human
  • Simvastatin
  • Proto-Oncogene Proteins p21(ras)
  • Cetuximab