Fulvestrant and everolimus efficacy after CDK4/6 inhibitor: a prospective study with circulating tumor DNA analysis.

In a prospective study (NCT02866149), we assessed the efficacy of fulvestrant and everolimus in CDK4/6i pre-treated mBC patients and circulating tumor DNA (ctDNA) changes throughout therapy. Patients treated with fulvestrant and everolimus had their ctDNA assessed at baseline, after 3-5 weeks and at disease progression. Somatic mutations were identified in archived tumor tissues by targeted NGS and tracked in cell-free DNA by droplet digital PCR. ctDNA detection was then associated with clinicopathological characteristics and patients' progression-free survival (PFS), overall survival (OS) and best overall response (BOR). In the 57 included patients, median PFS and OS were 6.8 (95%CI [5.03-11.5]) and 38.2 (95%CI [30.0-not reached]) months, respectively. In 47 response-evaluable patients, BOR was a partial response or stable disease in 15 (31.9%) and 11 (23.4%) patients, respectively. Among patients with trackable somatic mutation and available plasma sample, N = 33/47 (70.2%) and N = 19/36 (52.8%) had ctDNA detected at baseline and at 3 weeks, respectively. ctDNA detection at baseline and PIK3CA mutation had an adverse prognostic impact on PFS and OS in multivariate analysis. This prospective cohort study documents the efficacy of fulvestrant and everolimus in CDK4/6i-pretreated ER + /HER2- mBC and highlights the clinical validity of early ctDNA changes as pharmacodynamic biomarker.

Efficacy of taxanes rechallenge in first-line treatment of early metastatic relapse of patients with HER2-negative breast cancer previously treated with a (neo)adjuvant taxanes regimen: A multicentre retrospective observational study.

BACKGROUND: Taxanes are one of the most effective chemotherapies (CT) in breast cancer (BC), but the efficacy of taxanes rechallenge in early metastatic relapse has been poorly studied in patients previously treated by taxanes in the (neo)adjuvant setting. Our study aimed to analyse the efficacy of taxane rechallenge in case of early metastatic relapse in a multicentre retrospective observational study compared with other chemotherapies. METHODS: We analysed the French national ESME metastatic BC (MBC) database and selected HER2- MBC patients who received CT in first-line treatment for a metastatic relapse occurring 3-24 months after previous (neo)adjuvant taxanes treatment. RESULTS: Of 23,501 female patients with MBC in ESME, 1057 met the selection criteria. 58.4% received a taxane-based regimen (75.4% concomitant bevacizumab) and 41.6% received other CT. In hormone-receptor positive (HR+)/HER2- MBC, multivariate analysis showed no difference in OS between taxanes without bevacizumab compared to other CT (HZR = 1.3 [0.97; 1.74], but taxanes was significantly associated with worse PFS (HZR = 1.48 [1.14; 1.93]). In TNBC, taxanes without bevacizumab and carboplatin/gemcitabine were not superior to other CT for OS (HZR = 1.07 [0.79; 1.44] and HZR = 0.81 [0.58; 1.13], respectively), while for PFS, taxanes was inferior (HZR = 1.33 [1.06-1.67]) and carboplatin plus gemcitabine was superior to other CT (HZR = 0.63 [0.46; 0.87]). For both subtypes, the worse outcome observed with paclitaxel was no longer observed with the addition of bevacizumab. CONCLUSIONS: With the limitation of retrospective design, taxanes rechallenge in early metastatic relapse of BC may result in a worse PFS in TNBC and HR+/HER2- MBC, which was not observed with the addition of bevacizumab.

Clinical utility of circulating tumor cells: an update.

The prognostic role of circulating tumor cells (CTCs) has been clearly demonstrated in many types of cancer. However, their roles in diagnostic and treatment strategies remain to be defined. In this review, we present an overview of the current clinical validity of CTCs in nonmetastatic and metastatic cancer, and the main studies or concepts investigating the clinical utility of CTCs. In particular, we focus on breast, lung, colorectal, and prostate cancer. Two major topics concerning the clinical utility of CTC are discussed: treatment based on CTC count or CTC variations, and treatment based on the molecular characteristics of CTCs. Although some of these studies are inconclusive, many are still ongoing, and their results could help to define the role of CTCs in the management of cancers. A summary of published or ongoing phase II-III trials is also presented.

Prognostic value of CEC count in HER2-negative metastatic breast cancer patients treated with bevacizumab and chemotherapy: a prospective validation study (UCBG COMET).

BACKGROUND: Proof of concept studies has reported that circulating endothelial cell (CEC) count may be associated with the outcome of HER2-negative metastatic breast cancer (mBC) patients treated by chemotherapy and the anti-VEGF antibody bevacizumab. We report the results obtained in an independent prospective validation cohort (COMET study, NCT01745757). METHODS: The main baseline criteria were HER2-negative mBC, performance status 0-2 and no prior chemotherapy for metastatic disease. CECs were detected by CellSearch® from 4 ml of blood at baseline and after 4 weeks of weekly paclitaxel and bevacizumab therapy. CEC counts (considered both as a continuous variable and using the previously described 20 CEC/4 ml cutoff) were associated with clinical characteristics and progression-free survival (PFS). RESULTS: CEC count was obtained in 251 patients at baseline and in 207 patients at 4 weeks. Median baseline CEC count was 22 CEC/4 ml (range 0-2231). Baseline CEC counts were associated with performance status (p = 0.02). No statistically significant change in CEC counts was observed between baseline and 4 weeks of therapy. High baseline CEC count was associated with shorter PFS in univariate and multivariate analyses (continuous: p < 0.001; dichotomized: HR 1.52, 95% CI [1.15-2.02], p = 0.004). CEC counts at 4 weeks had no prognostic impact. CONCLUSION: This study confirms that CEC count may be associated with the outcome of mBC patients treated with chemotherapy and bevacizumab. However, discrepancies with previous reports in terms of both the timing of CEC count and the direction of the prognostic impact warrant further clinical investigation.