Bevacizumab and its impact on survival for patients receiving subsequent anti-EGFR therapy: Updated results from the SA metastatic CRC registry
Date
2017
Authors
Price, T.J.
Karapetis, C.S.
Padbury, R.
Burge, M.E.
Roy, A.C.
Maddern, G.
Roder, D.
Piantadosi, C.
Townsend, A.R.
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Journal article
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Journal of Clinical Oncology, 2017; 35(3569):1-1
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Abstract
Background: Debate exists as to whether first line bevacizumab effects subsequent sensitivity to anti-EGFR therapy. Authors hypothesize that initial anti-VEGF therapy may induce biological changes that then increase the risk of acquired resistance to subsequent EGFR inhibitors
Methods: A retrospective cohort study was performed to compare the characteristics and survival of patients who were treated with an anti-EGFR therapy 2nd line and beyond by two groups defined by the first line therapy; 1. chemotherapy (chemo) plus bevacizumab (bev) and 2. chemo alone. Survival for this analysis is from the time of commencing first line chemotherapy and secondly from anti-EGFR therapy. Pearson chi test analysis was performed to determine whether receiving first line bev was associated with worse overall survival (OS).
Results: 348 mCRC patients who received chemo with or without bev and then an anti-EGFR therapy were studied. Patient characteristics are summarised in the table below. The significant differences between group 1. Vs. 2. were as follows; median age 63.8 years v 67.9 years (p = 0.005), lower use of single agent FU 6.4% v 19.2%, KRAS status not tested (reflecting the practice changes over time) 19.3% v 39.2%, KRAS MT 2% v 4%, and where BRAF MT status was known (11%); BRAF MT rate 23% v 0. Median OS for the 2 groups was 34.2 months, and 28.2 months respectively (p = 0.12) from first line therapy. Median OS for patients who underwent single agent anti-EGFR as subsequent therapy was also not significantly different, 31.1 months group 1 (n = 60) versus 27.7 months group 2 (n = 85), p = 0.52. Results based on commencement of anti-EGFR therapy are under way.
Conclusions: Survival was not significantly different between the two groups, and the trend was towards higher OS with chemo plus bev suggesting that in our registry population, bev administration in first line therapy with chemo did not lead to a worse outcome overall for those patients subsequently receiving anti-EGFR therapy, either with chemotherapy or as a single agent. Updated results from commencement of anti-EGFR therapy will give further insights and will be presented at the meeting.
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Copyright 2017 American Society of Clinical Oncology