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Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies
Published on: September 30, 2016
TP53 mutational status and cetuximab benefit in rectal cancer: 5-year results of the EXPERT-C trial
Francesco Sclafani1, David Gonzalez1, David Cunningham2
1Affiliations of authors: Department of Medicine, The Royal Marsden NHS Foundation Trust, London and Surrey, UK (FS, DG, DC, SHW, SP, AD, AW, GB, DT, JO, IC); Medical Oncology Department, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain (JT); Department of Radiology, Oncology and Radiation Science, Akademiska Sjukhuset Uppsala, Uppsala, Sweden (BG); Department of Hematology and Medical Oncology, INCLIVA Biomedical Research Institute, University of Valencia, Hospital Clinico de Valencia, Valencia, Spain (AC).
Abstract:
In this updated analysis of the EXPERT-C trial we show that, in magnetic resonance imaging-defined, high-risk, locally advanced rectal cancer, adding cetuximab to a treatment strategy with neoadjuvant CAPOX followed by chemoradiotherapy, surgery, and adjuvant CAPOX is not associated with a statistically significant improvement in progression-free survival (PFS) and overall survival (OS) in both KRAS/BRAF wild-type and unselected patients. In a retrospective biomarker analysis, TP53 was not prognostic but emerged as an independent predictive biomarker for cetuximab benefit. After a median follow-up of 65.0 months, TP53 wild-type patients (n = 69) who received cetuximab had a statistically significant better PFS (89.3% vs 65.0% at 5 years; hazard ratio [HR] = 0.23; 95% confidence interval [CI] = 0.07 to 0.78; two-sided P = .02 by Cox regression) and OS (92.7% vs 67.5% at 5 years; HR = 0.16; 95% CI = 0.04 to 0.70; two-sided P = .02 by Cox regression) than TP53 wild-type patients who were treated in the control arm. An interaction between TP53 status and cetuximab effect was found (P < .05) and remained statistically significant after adjusting for statistically significant prognostic factors and KRAS.

