Noelia Tarazona

Analysis of ESR1 mutation in circulating tumor DNA demonstrates evolution during therapy for metastatic breast cancer.

ESR1 mutations evolve during the treatment of metastatic breast cancer. An evolving problem A large number of breast cancers express the estrogen receptor, making them susceptible to hormonal treatments. Unfortunately, these tumors can develop mutations in the estrogen receptor gene (ESR1) and become resistant to hormonal therapies that were previously effective. Schiavon et al. used three independent cohorts of breast cancer patients to demonstrate that these mutations only evolved in cases where hormonal therapy was started late in the course of the disease, after development of metastasis, and not during the initial course of treatment. If these findings are confirmed in prospective clinical trials, then they will explain why starting hormonal treatment early decreases the risk of subsequent resistance to hormonal therapy. Acquired ESR1 mutations are a major mechanism of resistance to aromatase inhibitors (AIs). We developed ultra high–sensitivity multiplex digital polymerase chain reaction assays for ESR1 mutations in circulating tumor DNA (ctDNA) and investigated the clinical relevance and origin of ESR1 mutations in 171 women with advanced breast cancer. ESR1 mutation status in ctDNA showed high concordance with contemporaneous tumor biopsies and was accurately assessed in samples shipped at room temperature in preservative tubes. ESR1 mutations were found exclusively in estrogen receptor–positive breast cancer patients previously exposed to AI. Patients with ESR1 mutations had a substantially shorter progression-free survival on subsequent AI-based therapy [hazard ratio, 3.1; 95% confidence interval (CI), 1.9 to 23.1; P = 0.0041]. ESR1 mutation prevalence differed markedly between patients who were first exposed to AI during the adjuvant and metastatic settings [5.8% (3 of 52) versus 36.4% (16 of 44), respectively; P = 0.0002]. In an independent cohort, ESR1 mutations were identified in 0% (0 of 32; 95% CI, 0 to 10.9) tumor biopsies taken after progression on adjuvant AI. In a patient with serial sampling, ESR1 mutation was selected during metastatic AI therapy to become the dominant clone in the cancer. ESR1 mutations can be robustly identified with ctDNA analysis and predict for resistance to subsequent AI therapy. ESR1 mutations are rarely acquired during adjuvant AI but are commonly selected by therapy for metastatic disease, providing evidence that mechanisms of resistance to targeted therapy may be substantially different between the treatment of micrometastatic and overt metastatic cancer.

Current questions for the treatment of advanced gastric cancer.

BACKGROUND Gastric cancer remains a major health problem worldwide. Treatment of advanced gastric cancer is controversial and there is no standard regimen for first- or second-line chemotherapy (CT). This review aims to give an overview of the hot topics concerning treatment, prognostic factors and new strategies in advanced gastric cancer. MATERIAL AND METHODS Seven questions of special clinical interest have been formulated previously to the literature review. With the aim of answering each of these questions, a specific search of the relevant trials and meta-analyses published or communicated from 1990 to date was performed. RESULTS Patients treated with CT have a survival benefit over those treated with only best supportive care (BSC). Such active cytotoxic drugs as cisplatin or docetaxel and targeted agents as trastuzumab showed superiority in randomized trials. Other agents such as oxaliplatin, oral fluoropyrimidines and irinotecan showed non-inferiority or less toxic results, positioning them as valuable alternatives to classical schedules. Combination regimens seem to be an improvement over single agent therapy. However, increased toxicity of some regimens makes their general use difficult. Second-line CT is of value for selected patients with good performance status. Trastuzumab is the only targeted agent showing better survival when added to chemotherapy in HER2-driven tumors. CONCLUSIONS With the introduction of new agents, management of advanced gastric cancer has experienced important changes. First and second-line CT improve survival in patients with good performance status. Future trials should address how to better select patients for new, targeted agents, based upon validated predictive biomarkers.

High-Level Clonal FGFR Amplification and Response to FGFR Inhibition in a Translational Clinical Trial

UNLABELLED FGFR1 and FGFR2 are amplified in many tumor types, yet what determines response to FGFR inhibition in amplified cancers is unknown. In a translational clinical trial, we show that gastric cancers with high-level clonal FGFR2 amplification have a high response rate to the selective FGFR inhibitor AZD4547, whereas cancers with subclonal or low-level amplification did not respond. Using cell lines and patient-derived xenograft models, we show that high-level FGFR2 amplification initiates a distinct oncogene addiction phenotype, characterized by FGFR2-mediated transactivation of alternative receptor kinases, bringing PI3K/mTOR signaling under FGFR control. Signaling in low-level FGFR1-amplified cancers is more restricted to MAPK signaling, limiting sensitivity to FGFR inhibition. Finally, we show that circulating tumor DNA screening can identify high-level clonally amplified cancers. Our data provide a mechanistic understanding of the distinct pattern of oncogene addiction seen in highly amplified cancers and demonstrate the importance of clonality in predicting response to targeted therapy. SIGNIFICANCE Robust single-agent response to FGFR inhibition is seen only in high-level FGFR-amplified cancers, with copy-number level dictating response to FGFR inhibition in vitro, in vivo, and in the clinic. High-level amplification of FGFR2 is relatively rare in gastric and breast cancers, and we show that screening for amplification in circulating tumor DNA may present a viable strategy to screen patients. Cancer Discov; 6(8); 838-51. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 803.

Deregulation of ARID1A, CDH1, cMET and PIK3CA and target-related microRNA expression in gastric cancer

Genetic and epigenetic alterations play an important role in gastric cancer (GC) pathogenesis. Aberrations of the phosphatidylinositol-3-kinase signaling pathway are well described. However, emerging genes have been described such as, the chromatin remodeling gene ARID1A. Our aim was to determine the expression levels of four GC-related genes, ARID1A, CDH1, cMET and PIK3CA, and 14 target-related microRNAs (miRNAs). We compared mRNA and miRNA expression levels among 66 gastric tumor and normal adjacent mucosa samples using quantitative real-time reverse transcription PCR. Moreover, ARID1A, cMET and PIK3CA protein levels were assessed by immunohistochemistry (IHC). Finally, gene and miRNAs associations with clinical characteristics and outcome were also evaluated. An increased cMET and PIK3CA mRNA expression was found in 78.0% (P = 2.20 × 10−5) and 73.8% (P = 1.00 × 10−3) of the tumors, respectively. Moreover, IHC revealed that cMET and PIK3CA expression was positive in 63.6% and 87.8% of the tumors, respectively. Six miRNAs had significantly different expression between paired-samples, finding five up-regulated [miR-223-3p (P = 1.65 × 10−6), miR-19a-3p (P = 1.23 × 10−4), miR-128-3p (P = 3.49 × 10−4), miR-130b-3p (P = 1.00 × 10−3) and miR-34a-5p (P = 4.00 × 10−3)] and one down-regulated [miR-124-3p (P = 0.03)]. Our data suggest that cMET, PIK3CA and target-related miRNAs play an important role in GC and may serve as potential targets for therapy.

Exclusion of Gastrointestinal Cancer Patients With Prior Cancer From Clinical Trials: Is This Justified?

BACKGROUND Strict eligibility criteria are necessary to maintain patient safety and scientific validity in clinical trials. However, this may lead to impaired generalizability of results. As survival in gastrointestinal (GI) cancer relates mainly to the GI malignancy, we hypothesized that previous cancers do not impact on survival and are not a rational exclusion criterion. MATERIALS AND METHODS Patients treated with chemotherapy for a GI cancer in 2006 were identified from the electronic patient record at the Royal Marsden Hospital, London. Chart review was performed and patient age, gender, GI cancer stage, prior cancer stage, clinical trial availability/eligibility, and dates of cancer recurrence, death, and last follow-up were collated. RESULTS A total of 697 patients were identified. Fifty-four patients (8%) had a prior cancer; commonly breast (26%), prostate (17%), or colon (9%); most were stage I (42%) or II (37%). Two hundred ninety-seven (65%) patients had GI cancer recurrence, 7 (12%) patients had relapse of a prior cancer. Five hundred four (72%) patients have died, 170 (24%) are alive with no cancer, and 23 (3%) patients are alive with cancer. A total of 476 (94%) died of GI cancer, 2 (0.3%) of their prior cancer. Of all patients, 489 (70%) had an available trial, but 30% of patients with a prior cancer were ineligible for this reason. Overall and GI-cancer-specific survival were comparable for patients with/without a prior cancer. CONCLUSIONS Survival for patients with a GI cancer requiring chemotherapy relates to the GI cancer and rarely a prior cancer. These patients should not be excluded from clinical trial participation.

Ramucirumab: targeting angiogenesis in the treatment of gastric cancer

Gastroesophageal cancer is responsible for over 1 million deaths annually worldwide; for patients with advanced disease treatment options are limited. Angiogenesis is an attractive therapeutic target that has been successfully exploited in other cancers. Ramucirumab, a fully humanized monoclonal antibody targeting VEGFR-2 has demonstrated efficacy as a single agent and in combination with paclitaxel in two large randomized trials (REGARD and RAINBOW) for the treatment of advanced previously treated gastroesophageal cancer. In combination with paclitaxel chemotherapy ramucirumab treated patients demonstrated increased rates of neutropenia, and ramucirumab is also associated with hypertension consistent with other antiangiogenic agents. Ramucirumab has been US FDA approved for patients with advanced gastroesophageal cancer who have progressed during or after treatment with fluoropyrimidine- or platinum-containing chemotherapy.

KRAS and BRAF mutations in circulating tumour DNA from locally advanced rectal cancer

There are limited data on circulating, cell-free, tumour (ct)DNA analysis in locally advanced rectal cancer (LARC). Digital droplet (dd)PCR was used to investigate KRAS/BRAF mutations in ctDNA from baseline blood samples of 97 LARC patients who were treated with CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX ± cetuximab in a randomised phase II trial. KRAS mutation in G12D, G12V or G13D was detected in the ctDNA of 43% and 35% of patients with tumours that were mutant and wild-type for these hotspot mutations, respectively, according to standard PCR-based analyses on tissue. The detection rate in the ctDNA of 10 patients with less common mutations was 50%. In 26 cases ctDNA analysis revealed KRAS mutations that were not previously found in tissue. Twenty-two of these (84.6%) were detected following repeat tissue testing by ddPCR. Overall, the ctDNA detection rate in the KRAS mutant population was 66%. Detection of KRAS mutation in ctDNA failed to predict prognosis or refine patient selection for cetuximab. While this study confirms the feasibility of ctDNA analysis in LARC and the high sensitivity of ddPCR, larger series are needed to better address the role of ctDNA as a prognostic or predictive tool in this setting.

The role of chemotherapy in localized and locally advanced rectal cancer: A systematic revision.

Curative treatment of rectal cancer depends on an optimal surgical resection, with the addition of neoadjuvant radiotherapy (RT) with or without concomitant chemotherapy (ChT) in more advanced tumors. The role of adjuvant ChT is controversial and a more intensified neoadjuvant approach with the addition of ChT before or after RT, or even as single modality, is currently being explored in trials. A systematic review selecting randomised phase II and III trials on the role of ChT in localized rectal cancer was performed. Data show that neoadjuvant ChRT improves locoregional control in resected rectal cancer. Short-course RT (SCRT) could give similar outcomes to ChRT. The addition of oxaliplatin to neoadjuvant ChRT marginally increases the pathological complete remission rate without improving survival and increasing toxicity. A more intensified approach remains investigational as trials to date have not shown significant advantages. Adjuvant ChT trials after preoperative ChRT are contentious, although the addition of oxaliplatin in high risk patients may benefit outcomes. Despite a wide heterogeneity in the target population, different staging procedures and diverse treatment approaches among different trials, this systematic review confirms the role of ChT in combination with neoadjuvant long-course RT. Adjuvant ChT could be of value in selected patients with high-risk features, mainly if they do not respond to neoadjuvant RT. Further investigation is warranted on more intensified neoadjuvant regimens including ChT for MRI-defined high-risk patients.

Clinical pharmacokinetics and pharmacodynamics of ramucirumab in the treatment of colorectal cancer

ABSTRACT Introduction: Colorectal cancer is the third most common cancer worldwide. The prognosis of colorectal cancer patients still remains dismal and half of them will develop metastatic disease. Angiogenesis plays an essential role in colorectal tumorigenesis, and the VEGF pathway is one of the targets that has been validated up to now. The use of antiangiogenics along with chemotherapy has become an accepted standard for colorectal cancer. Areas covered: This review discusses the efficacy and safety profile of ramucirumab, a fully human immunoglobulin G1 monoclonal antibody against the vascular endothelial growth factor receptor-2 (VEGFR-2), for the treatment of second-line metastatic colorectal cancer upon progression to first-line chemotherapy including anti-angiogenics. Expert opinion: Ramucirumab in combination with chemotherapy represents a valid option in second-line treatment of advanced colorectal cancer patients, who progressed on previous bevacizumab-based combinations. This agent demonstrates a similar benefit in terms of overall survival to other angiogenesis inhibitors (bevacizumab and ziv-aflibercept) used in this setting.

Personalised Treatment in Gastric Cancer: Myth or Reality?

Despite recent diagnostic and therapeutic advances, the survival of patients with gastric cancer is still poor. The majority of patients are diagnosed with advanced disease and chemotherapy represents the only possible therapeutic approach. However, chemotherapy seems to have reached an efficacy plateau in this setting. Gastric cancer is a complex and heterogeneous disease because it emerges from multiple interactions of genetic, environmental and host factors. A better understanding of its molecular characteristics may lead to an improvement of outcomes. The recent molecular classification by The Cancer Genome Atlas project divides gastric cancer into four subtypes that could be taken into consideration in future clinical trials with targeted agents. So far trastuzumab, a monoclonal antibody addressing the HER2 receptor, is the only targeted agent approved in the first-line setting, but only in patients overexpressing HER2. Negative data have been obtained in first-line therapy when antiangiogenics, anti-EGFR or anti-MET monoclonal antibodies have been studied in randomised controlled trials. Ramucirumab, a monoclonal antibody binding to VEGFR2, is the only antiangiogenic agent currently recommended in patients progressing after first-line treatment. In this review, we discuss whether personalised therapy may have a role in gastric cancer.