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Background:\ud \ud Molecular characteristics of cancer vary between individuals. In future, most trials will require assessment of biomarkers to allocate patients into enriched populations in which targeted therapies are more likely to be effective. The MRC FOCUS3 trial is a feasibility study to assess key elements in the planning of such studies.\ud \ud \ud Patients and Methods:\ud \ud Patients with advanced colorectal cancer were registered from 24 centres between February 2010 and April 2011. With their consent, patients’ tumour samples were analysed for KRAS/BRAF oncogene mutation status and topoisomerase 1 (topo-1) immunohistochemistry. Patients were then classified into one of four molecular strata; within each strata patients were randomised to one of two hypothesis-driven experimental therapies or a common control arm (FOLFIRI chemotherapy). A 4-stage suite of patient information sheets (PISs) was developed to avoid patient overload.\ud \ud \ud Results:\ud \ud A total of 332 patients were registered, 244 randomised. Among randomised patients, biomarker results were provided within 10 working days (w.d.) in 71%, 15 w.d. in 91% and 20 w.d. in 99%. DNA mutation analysis was 100% concordant between two laboratories. Over 90% of participants reported excellent understanding of all aspects of the trial. In this randomised phase II setting, omission of irinotecan in the low topo-1 group was associated with increased response rate and addition of cetuximab in the KRAS, BRAF wild-type cohort was associated with longer progression-free survival.\ud \ud \ud Conclusions:\ud \ud Patient samples can be collected and analysed within workable time frames and with reproducible mutation results. Complex multi-arm designs are acceptable to patients with good PIS. Randomisation within each cohort provides outcome data that can inform clinical practice.

It is likely that future trials for many solid tumours will be stratified by predictive/prognostic biomarkers in order to a) derive more homogeneous patient cohorts; b) "personalize" treatment interventions in relation to tumour (or host) phenotype; and c) improve the likelihood of discovering a beneficial effect, in at least a subset of patients with the disease. In some settings there are likely to be multiple relevant biomarkers and treatments to be tested. For logistical reasons it would be efficient to combine these into single trials. Moreover, the inclusion of overlapping or common treatment arms could serve to further validate the use of a given biomarker for selection and support retrospective testing of other biomarker selection algorithms that may arise during the course of a trial’s enrolment period. These requirements present significant challenges both for creating efficient designs and for making these comprehensible for prospective subjects. Methods: FOCUS 3 is a feasibility study designed to address these issues and test a novel design for examining the predictive role of biomarkers (KRAS/BRAF mutations and topo-1 expression) for 1st-line therapy of aCRC. It employs an unusual design in which the two biomarkers defined four possible cohorts. Specific treatment questions were relevant to each marker and, because each cohort was defined by 2 markers, there were 2 relevant experimental arms for each cohort, plus 1 common control arm for all cohorts (FOLFIRI). The study thus incorporates 5 treatment regimens, but only 3 possibilities for each patient, defined by marker phenotype. We will complete recruitment of 240 patients by April 2011. Paraffin blocks from 24 sites were obtained for central biomarker analysis and aim to feedback results within 10 working days. A 4 stage suite of patient information sheets (PIS) was designed to avoid patient overload and we are assessing patients’ comprehension in a qualitative study. Conclusion: Patient samples can be collected and analysed centrally within acceptable time constraints. Complex, stratified, multi arm designs can be made acceptable to patients through good PIS design, ensured by patient and carer input into their design.

Background: When cure is impossible, cancer treatment should focus on both length and quality of life. Maximisation of time without toxic effects could be one effective strategy to achieve both of these goals. The COIN trial assessed preplanned treatment holidays in advanced colorectal cancer to achieve this aim. Methods: COIN was a randomised controlled trial in patients with previously untreated advanced colorectal cancer. Patients received either continuous oxaliplatin and fluoropyrimidine combination (arm A), continuous chemotherapy plus cetuximab (arm B), or intermittent (arm C) chemotherapy. In arms A and B, treatment continued until development of progressive disease, cumulative toxic effects, or the patient chose to stop. In arm C, patients who had not progressed at their 12-week scan started a chemotherapy-free interval until evidence of disease progression, when the same treatment was restarted. Randomisation was done centrally (via telephone) by the MRC Clinical Trials Unit using minimisation. Treatment allocation was not masked. The comparison of arms A and B is described in a companion paper. Here, we compare arms A and C, with the primary objective of establishing whether overall survival on intermittent therapy was non-inferior to that on continuous therapy, with a predefined non-inferiority boundary of 1·162. Intention-to-treat (ITT) and per-protocol analyses were done. This trial is registered, ISRCTN27286448. Findings: 1630 patients were randomly assigned to treatment groups (815 to continuous and 815 to intermittent therapy). Median survival in the ITT population (n=815 in both groups) was 15·8 months (IQR 9·4–26·1) in arm A and 14·4 months (8·0–24·7) in arm C (hazard ratio [HR] 1·084, 80% CI 1·008–1·165). In the per-protocol population (arm A, n=467; arm C, n=511), median survival was 19·6 months (13·0–28·1) in arm A and 18·0 months (12·1–29·3) in arm C (HR 1·087, 0·986–1·198). The upper limits of CIs for HRs in both analyses were greater than the predefined non-inferiority boundary. Preplanned subgroup analyses in the per-protocol population showed that a raised baseline platelet count, defined as 400 000 per μL or higher (271 [28%] of 978 patients), was associated with poor survival with intermittent chemotherapy: the HR for comparison of arm C and arm A in patients with a normal platelet count was 0·96 (95% CI 0·80–1·15, p=0·66), versus 1·54 (1·17–2·03, p=0·0018) in patients with a raised platelet count (p=0·0027 for interaction). In the per-protocol population, more patients on continuous than on intermittent treatment had grade 3 or worse haematological toxic effects (72 [15%] vs 60 [12%]), whereas nausea and vomiting were more common on intermittent treatment (11 [2%] vs 43 [8%]). Grade 3 or worse peripheral neuropathy (126 [27%] vs 25 [5%]) and hand–foot syndrome (21 [4%] vs 15 [3%]) were more frequent on continuous than on intermittent treatment. Interpretation: Although this trial did not show non-inferiority of intermittent compared with continuous chemotherapy for advanced colorectal cancer in terms of overall survival, chemotherapy-free intervals remain a treatment option for some patients with advanced colorectal cancer, offering reduced time on chemotherapy, reduced cumulative toxic effects, and improved quality of life. Subgroup analyses suggest that patients with normal baseline platelet counts could gain the benefits of intermittent chemotherapy without detriment in survival, whereas those with raised baseline platelet counts have impaired survival and quality of life with intermittent chemotherapy and should not receive a treatment break. Funding: Cancer Research UK.