Patient-derived organoids (PDOs) have recently emerged as robust preclinical models; however, their potential to predict clinical outcomes in patients has remained unclear. We report on a living biobank of PDOs from metastatic, heavily pretreated colorectal and gastroesophageal cancer patients recruited in phase 1/2 clinical trials. Phenotypic and genotypic profiling of PDOs showed a high degree of similarity to the original patient tumors. Molecular profiling of tumor organoids was matched to drug-screening results, suggesting that PDOs could complement existing approaches in defining cancer vulnerabilities and improving treatment responses. We compared responses to anticancer agents ex vivo in organoids and PDO-based orthotopic mouse tumor xenograft models with the responses of the patients in clinical trials. Our data suggest that PDOs can recapitulate patient responses in the clinic and could be implemented in personalized medicine programs.

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.

Sequential profiling of plasma cell-free DNA (cfDNA) holds immense promise for early detection of patient progression. However, how to exploit the predictive power of cfDNA as a liquid biopsy in the clinic remains unclear. RAS pathway aberrations can be tracked in cfDNA to monitor resistance to anti-EGFR monoclonal antibodies in patients with metastatic colorectal cancer. In this prospective phase II clinical trial of single-agent cetuximab in wild-type patients, we combine genomic profiling of serial cfDNA and matched sequential tissue biopsies with imaging and mathematical modeling of cancer evolution. We show that a significant proportion of patients defined as wild-type based on diagnostic tissue analysis harbor aberrations in the RAS pathway in pretreatment cfDNA and, in fact, do not benefit from EGFR inhibition. We demonstrate that primary and acquired resistance to cetuximab are often of polyclonal nature, and these dynamics can be observed in tissue and plasma. Furthermore, evolutionary modeling combined with frequent serial sampling of cfDNA allows prediction of the expected time to treatment failure in individual patients. This study demonstrates how integrating frequently sampled longitudinal liquid biopsies with a mathematical framework of tumor evolution allows individualized quantitative forecasting of progression, providing novel opportunities for adaptive personalized therapies. Liquid biopsies capture spatial and temporal heterogeneity underpinning resistance to anti-EGFR monoclonal antibodies in colorectal cancer. Dense serial sampling is needed to predict the time to treatment failure and generate a window of opportunity for intervention. .

Highlights d NF1 and non-canonical KRAS and BRAF aberrations associate with cetuximab resistance d Genetic resistance drivers are absent in most biopsies that acquired resistance d Stromal remodeling is an alternative non-genetic mechanism of cetuximab resistance d Cetuximab-mediated immune modulation may sensitize CRCs to immunotherapy

BackgroundRecruitment to clinical trials can be challenging and slower than anticipated. This prospective patient survey aimed to investigate the proportion of patients approached about a trial who agree to participate, their motivations for trial participation and their views on aspects of cancer research.MethodsPatients who had been approached about participation in any clinical trials in the Gastrointestinal and Lymphoma Unit at the Royal Marsden were invited to complete a questionnaire. The statistical analysis is mainly descriptive, with percentages being reported. Univariate logistic regression analysis was used to determine any associations between patient characteristics and patient responses.ResultsFrom August 2013–July 2014, 276 patients received 298 clinical trial patient information sheets and were asked to complete the questionnaire. The majority of patients (263 patients, 88 %) consented to a clinical trial and 249 of the 263 patients (95 %) completed the questionnaire. Multiple factors influenced decisions to participate in clinical trials, with patients stating that the most important reasons were that the trial offered the best treatment available and that the trial results could benefit others. Of the 249 questionnaire respondents, 78 % would donate their tissue for genetic research, 75 % would consider participating in studies requiring a research biopsy and 75 % felt that patients should be informed of trial results. Patients treated with palliative intent and those who had received multiple lines of treatment were more willing to consider research biopsies. Of the patients approached about a clinical trial of an investigational medicinal product, 48–50 % would have liked more information on the study drugs/procedures.ConclusionThe majority of patients approached about a clinical trial consented to one or more trials. Patients’ motivations for trial participation included potential personal benefit and altruistic reasons. A high proportion of patients were willing to donate tissue for research and to consider trials involving repeat biopsies. The majority of patients feel that participants should be informed of trial results and there is a group of patients who would like more detailed trial information.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-015-1105-3) contains supplementary material, which is available to authorized users.