101. Vascular endothelial growth factor A (VEGF-A) amplification and long-term response to ramucirumab (ram) in metastatic gastric cancer (mGC): The VERA study
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Mariantonietta Di Salvatore, Serena Saggio, Salvatore Corallo, Maria Di Bartolomeo, Patrizia Gasparini, Maria Maddalena Laterza, Lorenzo Fornaro, Sabina Murgioni, Claudio Lotesoriere, Monica Niger, Maria Antista, Filippo Pietrantonio, Alessandra Raimondi, Antonia Martinetti, Sara Lonardi, Filippo de Braud, Elisa Giommoni, Serenella M. Pupa, Federica Morano, and Gabriella Sozzi
- Subjects
Cancer Research ,biology ,medicine.drug_class ,business.industry ,VEGF receptors ,Monoclonal antibody ,Ramucirumab ,Metastatic gastric cancer ,Vascular endothelial growth factor A ,chemistry.chemical_compound ,Long term response ,Oncology ,Paclitaxel ,chemistry ,biology.protein ,Cancer research ,medicine ,business - Abstract
3143 Background: The anti-VEGFR-2 monoclonal antibody ram, alone or with paclitaxel, is a cornerstone of second-line treatment of mGC. Even if about half patients do not benefit from ram, no predictive biomarkers have been identified so far. In TCGA, VEGF-A amplification was found in 7% of cases, almost exclusively in chromosomal instability subtype. We hypothesize that VEGF-A amplification in tumor cells could lead to autocrine/paracrine stimulation of tumor growth beside angiogenesis, potentially identifying a patients’ subgroup with exceptional responses to ram. Methods: VERA was a multicentric, prospective study based on a translational hypothesis. mGC patients were included according to the following criteria: 1) complete (CR) or partial response (PR) to single-agent ram; 2) >6 months PFS to single-agent ram; 3) >10 months PFS to paclitaxel+ram. According to a Fleming single-stage design, hypothesizing a prevalence of VEGF-A amplification of 1% and 15% among all-comers and exceptional responders, 20 exceptional responders were required to reject the null hypothesis of low prevalence of VEGF-A amplification, with alpha- and beta- errors of 0.05 and 0.10, respectively. VEGF-A amplification (defined as >10% tumor cells with ≥10 VEGF-A copies, variably sized signal clusters or a ratio of VEGF-A gene to centromere of ≥2) was centrally assessed through fluorescent in situ hybridization on pre-treatment FFPE tumor tissue. Results: At 7 Italian Centers, we included 20 patients satisfying the 1st (n=1), 2nd (n=2), or 3rd (n=17) criterion. Clinical-pathological features were: M/F, 11/9; median age 63 years; gastric/GEJ, 17/3; intestinal/diffuse, 14/6, HER2+/HER2-, 4/16. Median PFS and overall survival to ram-based treatment were 15.6 and 25.7 months, with best response: CR/PR/SD, 0/10/10. VERA met its primary endpoint, revealing 3/20 (15%) tumors with VEGF-A amplification (1 case presenting big clusters, 1 small clusters and 1 with >10% tumor cells with ≥10 VEGF-A copies). Conclusions: Validation analyses of first- and second-line randomized trials could confirm VEGF-A amplification as a biomarker of long-term response to ram-based treatment in mGC patients, advancing treatment personalization.
- Published
- 2019
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