Objective responses can be obtained by CTLA-4 inhibition in metastatic melanoma after BRAF inhibitor failure

Melanoma Res. 2015 Feb;25(1):68-74. doi: 10.1097/CMR.0000000000000131.

Abstract

The aim of this study was to determine the activity of ipilimumab (ipi)-based therapy after treatment failure with a BRAF inhibitor (BRAFi). Sixty-four patients with unresectable stage III or stage IV BRAF V600-mutant melanoma who were treated sequentially with a BRAFi and ipi-based therapy [ipi as monotherapy or ipi in combination with an autologous mRNA electroporated dendritic cell vaccine (TriMixDC-MEL)] were identified. Thirty-three patients had been treated with a BRAFi before ipi-based therapy (BRAFi-first), and 31 patients had been treated with ipi-based therapy first (ipi-first). In patients treated with a BRAFi first (n=33), the best response on sequential ipi-based therapy was three complete responses and six partial responses (best objective response rate of 27%). In patients treated with ipi-based therapy first (n=31), the best response on ipi-based therapy was 0 complete response and four partial responses (best objective response rate of 13%). The response rate did not differ significantly between the two groups (P=0.14). The median overall survival from the start of ipi-based therapy was 10 months (95% confidence interval: 5.7-14.3) in the BRAFi-first group and 12.3 months (95% confidence interval: 7.4-17.2) in the ipi-first group (P=0.34). We report that objective tumor responses to ipi-based immunotherapy can still be obtained after progression has occurred upon treatment with a BRAFi. A part of this observation might be related to the results obtained with a combination of ipi and TriMixDC-MEL.

MeSH terms

  • Antibodies, Monoclonal / therapeutic use*
  • Biomarkers / metabolism
  • CTLA-4 Antigen / metabolism*
  • Cancer Vaccines / therapeutic use
  • Disease Progression
  • Electroporation
  • Humans
  • Immunotherapy / methods
  • Ipilimumab
  • Melanoma / drug therapy*
  • Melanoma / metabolism
  • Neoplasm Metastasis
  • Predictive Value of Tests
  • Proto-Oncogene Proteins B-raf / antagonists & inhibitors*
  • RNA, Messenger / metabolism
  • Retrospective Studies
  • Skin Neoplasms / drug therapy*
  • Skin Neoplasms / metabolism
  • Treatment Outcome

Substances

  • Antibodies, Monoclonal
  • Biomarkers
  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Cancer Vaccines
  • Ipilimumab
  • RNA, Messenger
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf