Prognostic and predictive blood-based biomarkers in patients with advanced pancreatic cancer: Results from CALGB 80303 (Alliance)
A partir de données portant sur 602 patients atteints d'un cancer métastatique ou localement avancé du pancréas et inclus dans un essai de phase III évaluant le bevacizumab en combinaison avec la gemcitabine, cette étude identifie une signature, basée sur la mesure des niveaux plasmatiques de VEGF-D, Ang2 et SDF1, en association avec la réponse thérapeutique
CALGB80303 was a phase III trial of 602 patients with locally advanced or metastatic pancreatic cancer comparing gemcitabine/bevacizumab vs. gemcitabine/placebo. The study found no benefit in any outcome from the addition of bevacizumab to gemcitabine. Blood samples were collected and multiple angiogenic factors were evaluated and then correlated with clinical outcome in general (prognostic markers) and with benefit specifically from bevacizumab treatment (predictive markers). Plasma samples were analyzed via a novel multiplex ELISA platform for 31 factors related to tumor growth, angiogenesis, and inflammation. Baseline values for these factors were correlated with overall survival using univariate Cox proportional hazard regression models and multivariable Cox regression models with leave-one-out cross validation. Predictive markers were identified using a treatment by marker interaction term in the Cox model. Baseline plasma was available from 328 patients. Univariate prognostic markers for OS were identified including: Ang2, CRP, ICAM-1, IGFBP-1, TSP-2 (all p<0.001). These prognostic factors were found to be highly significant, even after adjustment for known clinical factors. Additional modeling approaches yielded prognostic signatures from multivariable Cox regression. The gemcitabine/bevacizumab signature consisted of IGFBP-1, IL-6, PDGF-AA, PDGF-BB, TSP-2; while the gemcitabine/placebo signature consisted of CRP, IGFBP-1, PAI-1, PDGF-AA, P-selectin (both p<0.0001). Lastly, three potential predictive markers of bevacizumab efficacy were identified: VEGF-D (p<0.01), SDF1 (p<0.05), and Ang2 (p<0.05). This study identified strong prognostic markers for pancreatic cancer patients. Predictive marker analysis indicated that plasma levels of VEGF-D, Ang2, and SDF1 significantly predicted for benefit or lack of benefit from bevacizumab in this population.
Clinical Cancer Research , résumé, 2013