Targeting the Wnt Pathway and Cancer Stem Cells with Anti-progastrin Humanized Antibodies as a Potential Treatment for K-RAS-Mutated Colorectal Cancer

International audiencePatients with metastatic colorectal cancer suffer from disease relapse mainly due to cancer stem cells (CSC). Interestingly, they have an increased level of blood progastrin, a tumor-promoting peptide essential for the self-renewal of colon CSCs, which is also a direct β-catenin/TCF4 target gene. In this study, we aimed to develop a novel targeted therapy to neutralize secreted progastrin to inhibit Wnt signaling, CSCs, and reduce relapses.Experimental Design:Antibodies (monoclonal and humanized) directed against progastrin were produced and selected for target specificity and affinity. After validation of their effectiveness on survival of colorectal cancer cell lines harboring B-RAF or K-RAS mutations, their efficacy was assessedin vitroandin vivo, alone or concomitantly with chemotherapy, on CSC self-renewal capacity, tumor recurrence, and Wnt signaling.Results:We show that anti-progastrin antibodies decrease self-renewal of CSCs bothin vitroandin vivo, either alone or in combination with chemotherapy. Furthermore, migration and invasion of colorectal cancer cells are diminished; chemosensitivity is prolonged in SW620 and HT29 cells and posttreatment relapse is significantly delayed in T84 cells, xenografted nude mice. Finally, we show that the Wnt signaling activityin vitrois decreased, and, in transgenic mice developing Wnt-driven intestinal neoplasia, the tumor burden is alleviated, with an amplification of cell differentiation in the remaining tumors.Conclusions:Altogether, these data show that humanized anti-progastrin antibodies might represent a potential new treatment for K-RAS-mutated colorectal patients, for which there is a crucial unmet medical need.Clin Cancer Res; 23(17); 5267-80. \textcopyright2017 AACR

Fluorouracil-based adjuvant chemotherapy after preoperative chemoradiotherapy in rectal cancer: long-term results of the EORTC 22921 randomised study

International audienceBACKGROUND:EORTC trial 22921 examined the addition of preoperative or postoperative chemotherapy to preoperative radiotherapy in patients with rectal cancer. After a median follow-up of 5 years, chemotherapy-irrespective of timing-significantly improved local control. Adjuvant chemotherapy did not improve survival, but the Kaplan-Meier curves diverged, suggesting possible delayed benefit. Here, we report the updated long-term results.METHODS:We randomly assigned patients with clinical stage T3 or T4 resectable rectal cancer to receive preoperative radiotherapy with or without concomitant chemotherapy before surgery followed by either adjuvant chemotherapy or surveillance. Randomisation was done using minimisation with factors of institution, sex, T stage, and distance from the tumour to the anal verge. Study coordinators, clinicians, and patients were aware of assignment. Radiotherapy consisted of 45 Gy to the posterior pelvis in 25 fractions of 1·8 Gy over 5 weeks. Each course of chemotherapy consisted of fluorouracil (350 mg/m(2) per day intravenous bolus) and folinic acid (leucovorin; 20 mg/m(2) per day intravenous bolus). For preoperative chemotherapy, two courses were given (during weeks 1 and 5 of radiotherapy). Adjuvant chemotherapy was given in four cycles, every 3 weeks. The primary endpoint was overall survival. This analysis was done by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00002523.FINDINGS:1011 patients were randomly assigned to treatment between April, 1993, and March, 2003 (252 to preoperative radiotherapy and 253 to each of the other three groups). After a median follow-up of 10·4 years (IQR 7·8-13·1), 10-year overall survival was 49·4% (95% CI 44·6-54·1) for the preoperative radiotherapy group and 50·7% (45·9-55·2) for the preoperative radiotherapy and chemotherapy group (HR 0·99, 95% CI 0·83-1·18; p=0·91). 10-year overall survival was 51·8% (95% CI 47·0-56·4) for the adjuvant chemotherapy group and 48·4% (43·6-53·0) for the surveillance group (HR 0·91, 95% CI 0·77-1·09, p=0·32). 10-year disease-free survival was 44·2% (95% CI 39·5-48·8) for the preoperative radiotherapy group and 46·4% (41·7-50·9) for the preoperative radiotherapy and chemotherapy group (HR 0·93, 95% CI 0·79-1·10; p=0·38). 10-year disease-free survival was 47·0% (95% CI 42·2-51·6) for the adjuvant chemotherapy group and 43·7% (39·1-48·2) for the surveillance group (HR 0·91, 95% CI 0·77-1·08, p=0·29). At 10 years, cumulative incidence of local relapse was 22·4% (95% CI 17·1-27·6) with radiotherapy alone, 11·8% (7·8-15·8) with neoadjuvant radiotherapy and chemotherapy, 14·5% (10·1-18·9) with radiotherapy and adjuvant chemotherapy and 11·7% (7·7-15·6) with both adjuvant and neoadjuvant chemotherapy (p=0·0017). There was no difference in cumulative incidence of distant metastases (p=0·52). The frequency of long-term side-effects did not differ between the four groups (p=0·22).INTERPRETATION:Adjuvant fluorouracil-based chemotherapy after preoperative radiotherapy (with or without chemotherapy) does not affect disease-free survival or overall survival. Our trial does not support the current practice of adjuvant chemotherapy after preoperative radiotherapy with or without chemotherapy. New treatment strategies incorporating neoadjuvant chemotherapy are required

Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

International audienceThe aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed