Triple-Negative PAM50 Non-Basal Breast Cancer Subtype Predicts Benefit from Extended Adjuvant Capecitabine.

PURPOSE: Predictive biomarkers for capecitabine benefit in triple-negative breast cancer (TNBC) have been recently proposed using samples from phase III clinical trials, including non-basal phenotype and biomarkers related to angiogenesis, stroma, and capecitabine activation genes. We aimed to validate these findings on the larger phase III GEICAM/CIBOMA clinical trial. EXPERIMENTAL DESIGN: Tumor tissues from patients with TNBC randomized to standard (neo)adjuvant chemotherapy followed by capecitabine versus observation were analyzed using a 164-gene NanoString custom nCounter codeset measuring mRNA expression. A prespecified statistical plan sought to verify the predictive capacity of PAM50 non-basal molecular subtype and tested the hypotheses that breast tumors with increased expression of (meta)genes for cytotoxic cells, mast cells, endothelial cells, PDL2, and 38 individual genes benefit from adjuvant capecitabine for distant recurrence-free survival (DRFS; primary endpoint) and overall survival. RESULTS: Of the 876 women enrolled in the GEICAM/CIBOMA trial, 658 (75%) were evaluable for analysis (337 with capecitabine and 321 without). Of these cases, 553 (84%) were profiled as PAM50 basal-like whereas 105 (16%) were PAM50 non-basal. Non-basal subtype was the most significant predictor for capecitabine benefit [HRcapecitabine, 0.19; 95% confidence interval (CI), 0.07-0.54; P < 0.001] when compared with PAM50 basal-like (HRcapecitabine, 0.9; 95% CI, 0.63-1.28; P = 0.55; Pinteraction<0.001, adjusted P value = 0.01). Analysis of biological processes related to PAM50 non-basal subtype revealed its enrichment for mast cells, extracellular matrix, angiogenesis, and features of mesenchymal stem-like TNBC subtype. CONCLUSIONS: In this prespecified correlative analysis of the GEICAM/CIBOMA trial, PAM50 non-basal status identified patients with early-stage TNBC most likely to benefit from capecitabine.

Bevacizumab in advanced breast cancer: a new model for the assessment of activity in non-first-line treatment regimens.

The activity of bevacizumab (BVZ) in advanced lines is not well known. In the treatment of metastatic breast cancer, the response rate and time to treatment failure (TTF) decrease with progression through successive therapeutic lines. The objective of this study was to compare BVZ activity in advanced treatment lines with that achieved in the previous line in routine clinical practice. Ninety-six patients who had received BVZ treatment in second or subsequent treatment lines were selected from five Spanish hospitals. Analysis was carried out of the differences in TTF and response rate in the lines with BVZ and those in earlier lines. Data analysis was carried out in two different ways: (a) by comparing treatment groups according to the treatment line received, using a Cox regression model with random effects, and the McNemar test to analysis the response rate, and (b) by comparing intrapatient data, using the Wilcoxon signed-rank test. In 62 patients, the TTF (adjusted for treatment line) was longer in the BVZ treatment line than that in the previous line. In the BVZ lines, there was a significant reduction in the probability of treatment failure [hazard ratio 0.52; 95% confidence interval (CI) 0.38-0.71]. The median TTF was 4.27 months (95% CI 3.7-5) in the previous line and 6.18 months (95% CI 5.5-7.93) in the BVZ line. The percentage of patients with an objective response was 33.3% in the previous lines and 52.1% (P=0.005) in the BVZ line. Contrary to expectation, more patients showed better results with the BVZ line than with the previous line. BVZ treatment in advanced lines improves the results obtained in previous treatment lines. This suggests that BVZ is active in advanced lines and that it produces favourable changes in the natural history of patients with metastatic breast carcinoma.