Mark P. Saunders

BACKGROUND. Phase 1 study of ATR inhibition alone or with radiation therapy (PATRIOT) was a first-in-human phase I study of the oral ATR (ataxia telangiectasia and Rad3-related) inhibitor ceralasertib (AZD6738) in advanced solid tumors. METHODS. The primary objective was safety. Secondary objectives included assessment of antitumor responses and pharmacokinetic (PK) and pharmacodynamic (PD) studies. Sixty-seven patients received 20–240 mg ceralasertib BD continuously or intermittently (14 of a 28-day cycle). RESULTS. Intermittent dosing was better tolerated than continuous, which was associated with dose-limiting hematological toxicity. The recommended phase 2 dose of ceralasertib was 160 mg twice daily for 2 weeks in a 4-weekly cycle. Modulation of target and increased DNA damage were identified in tumor and surrogate PD. There were 5 (8%) confirmed partial responses (PRs) (40–240 mg BD), 34 (52%) stable disease (SD), including 1 unconfirmed PR, and 27 (41%) progressive disease. Durable responses were seen in tumors with loss of AT-rich interactive domain-containing protein 1A (ARID1A) and DNA damage–response defects. Treatment-modulated tumor and systemic immune markers and responding tumors were more immune inflamed than nonresponding. CONCLUSION. Ceralasertib monotherapy was tolerated at 160 mg BD intermittently and associated with antitumor activity. TRIAL REGISTRATION. Clinicaltrials.gov: NCT02223923, EudraCT: 2013-003994-84. FUNDING. Cancer Research UK, AstraZeneca, UK Department of Health (National Institute for Health Research), Rosetrees Trust, Experimental Cancer Medicine Centre.

Background: The primary aim was to test the hypothesis that deriving pre-treatment 3D magnetic resonance tumour volume (mrTV) quantification improves performance characteristics for the prediction of loco-regional failure compared with standard maximal tumour diameter (1D) assessment in patients with squamous cell carcinoma of the anus undergoing chemoradiotherapy.Methods: We performed an early evaluation case-control study at two UK centres (2007-2014) in 39 patients with loco-regional failure (cases), and 41 patients disease-free at 3 years (controls). mrTV was determined using the summation of areas method (Vol_sum). Reproducibility was assessed using intraclass concordance correlation (ICC) and Bland-Altman limits of agreements. We derived receiver operating curves using logistic regression models and expressed accuracy as area under the curve (ROC_AUC).Results: The median time per patient for Vol_sum quantification was 7.00 (inter-quartile range, IQR: 0.57-12.48) minutes. Intra and inter-observer reproducibilities were generally good (ICCs from 0.79 to 0.89) but with wide limits of agreement (intra-observer: -28% to 31%; inter-observer: -28% to 46%). Median mrTVs were greater for cases (32.6 IQR: 21.5-53.1 cm³) than controls (9.9 IQR: 5.7-18.1 cm³, p AUC for mrT-size predicting loco-regional failure was 0.74 (95% CI: 0.63-0.85) improving to 0.82 (95% CI: 0.72-0.92) when replaced with mrTV (test for ROC differences, p = 0.024).Conclusion: Preliminary results suggest that the replacement of mrTV for mrT-size improves prediction of loco-regional failure after chemoradiotherapy for squamous cell carcinoma of the anus. However, mrTV calculation is time consuming and variation in its reproducibility are drawbacks with the current technology.

Aim: To determine the concordance between plasma and tissue RAS mutation status in metastatic colorectal cancer patients to gauge whether blood-based testing is a viable alternative. We also evalua...

Cutaneous toxicities associated with EGFR inhibitors (EGFRIs) have a significant impact on patient treatment continuation, quality of life and healthcare resource utilization. This paper reviews the current prophylaxis and management of EGFRI-induced cutaneous toxicities in patients with colorectal cancer, and combines these findings with the authors’ clinical expertise to define a novel algorithm for healthcare professionals managing patients receiving EGFRIs. This tool includes a grading system based on the location, severity and psychological impact, and provides a standard prescription pack, advice on prophylaxis/self-management of cutaneous symptoms for patients initiating EGFRIs, and essential guidance on subsequent review and treatment escalation. It aims to optimize treatment of metastatic colorectal cancer by minimizing cutaneous toxicities to maintain dose intensity and efficacy of EGFRI-based chemotherapy.

11521 Background: VEGF inhibitor (VEGFi) use is compromised by lack of predictive/ response biomarkers. Previously, we identified plasma Tie2 (pTie2) as a vascular response biomarker (VRB) for bevacizumab (bev) in ovarian cancer (OC). Here, we applied dynamic contrast-enhanced MRI (DCE-MRI) and circulating biomarkers in colorectal cancer (CRC), to validate pTie2 as the first tumor VRB. Methods: Seventy patients were recruited, with untreated, mCRC and ≥1 lesion of 3-10cm diameter for DCE-MRI. Patients received bev 10mg/kg for 2 weeks to elicit a biomarker response and then FOLFOX6/bev until progressive disease (PD) Thirteen circulating and 6 imaging biomarkers were measured before and during treatment and at PD. Unsupervised correlation analysis identified bev-induced biomarker correlations. Biomarkers were evaluated by clustered parameter-time course studies to determine their epithelial or vascular origin. Clinical significance was determined by relating the biomarker data to tumor 3D volumetric change assessed by MRI and PFS. The emergent vascular biomarker signal was modelled with epithelial biomarkers to assess the independent contribution of the vascular compartment to PD. Results: Bev induced significant correlations between pTie2, Ang2 and K^trans. Cluster analysis of Tie2 concentration-time course curves showed that pTie2 reflected tumor K^transbut not CK18, an epithelial antigen, i.e. changes in pTie2 reflected tumor vascular biology Patients who had the greatest area under the pTie2-time curve had tumors with high K^transand/or low pVEGFR2, pre-treatment. They also had the greatest reduction in tumor volume and longest PFS. Fusion of pTie2 and CK18 data significantly improved modelling of PD. Conclusions: Bev impacts tumor vasculature causing proportional changes in pTie2. Information from pTie2 adds clinical value to that derived from the epithelial compartment. Thus (i) pTie2 is the first vascular response biomarker for bev and probably all VEGFi and (ii) demonstration of separate vascular and epithelial compartments in ovarian and CRC validates the vascular compartment as a target. This work identifies the first assay that could optimise use of VEGFi. Clinical trial information: 2009-011377-33.

Pharmacokinetic guided dosing of 5-fluorouracil chemotherapies to bring plasma 5-fluorouracil into a desired therapeutic range may lead to fewer side effects and better patient outcomes. High performance liquid chromatography and a high throughput nanoparticle immunoassay (My5-FU) have been used in conjunction with treatment algorithms to guide dosing. The objective of this study was to assess accuracy, clinical effectiveness and safety of plasma 5-fluorouracil guided dose regimen(s) versus standard regimens based on body surface area in colorectal cancer. We undertook a systematic review. MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations; EMBASE; Cochrane Library; Science Citation Index and Conference Proceedings (Web of Science); and NIHR Health Technology Assessment Programme were searched from inception to January 2014. We reviewed evidence on accuracy of My5-FU for estimating plasma 5-fluorouracil and on the clinical effectiveness of pharmacokinetic dosing compared to body surface area dosing. Estimates of individual patient data for overall survival and progression-free survival were reconstructed from published studies. Survival and adverse events data were synthesised and examined for consistency across studies. My5-FU assays were found to be consistent with reference liquid chromatography tandem mass spectrometry. Comparative studies pointed to gains in overall survival and in progression-free survival with pharmacokinetic dosing, and were consistent across multiple studies. Although our analyses are encouraging, uncertainties remain because evidence is mainly from outmoded 5-fluorouracil regimens; a randomised controlled trial is urgently needed to investigate new dose adjustment methods in modern treatment regimens.

458 Background: Little data exists comparing pre- and post-CRT EGFR pathway mutations in LARC. Methods: Patients had MRI-defined LARC threatening or involving the surgical resection margin. CRT used pelvic radiotherapy (RT) 45Gy in 25 daily fractions with concurrent capecitabine (650mg/m² bid PO 5 days/week), IV cetuximab (400mg/m² one week prior then weekly at 250mg/m² weeks 1-5) and IV irinotecan (weekly at 60mg/m²weeks 1-4). Surgery was 8 weeks after CRT. EGFR pathway mutations were not assessed prospectively. After study completion DNA was extracted from pre-treatment biopsies and post-resection specimens by macrodissecting areas of greatest tumour cell density. KRAS codons 12, 13, 61, 146, NRAS codons 12, 13, 61, PIK3CA codons 542, 545, 546, 1047 and the BRAF V600E hotspot were then pyrosequenced. Results: From 04/09-10/11, 80 patients commenced RT. 76 patients had surgery, with pathological complete response (CR) in 14 (18%) and near-complete (microfoci) in 6 (8%). Four patients had no surgery due to clinical CR. Pre-treatment mutation status was available in 78 patients with a KRAS codon mutation in 34 patients, BRAF in 3, NRAS in 3, PIK3CA in 10 and pathway (any mutation) in 45 (58%). Post-resection data in 54 patients showed 35 mutated codons in 32 patients (59%). 18 patients (33%) showed a discrepancy compared to pre-treatment biopsy. In 17 this was at a single codon, from wild-type (wt) to mutant (mut) in 9 (7x KRAS 12, 1x KRAS 13, 1x PIK3CA 542), from mut to mut in 1 (KRAS 12 c.35G>A to c.34G>T) and mut to wt in 7 (1x KRAS 12, 2x KRAS 13, 2x KRAS 146, 1x PIK3CA 542, 1x PIK3CA 545). One patient changed in 3 codons (mut to wt at KRAS 146 and PIK3CA 545 and wt to mut at KRAS 12). In 12 patients (22%) this changed overall EGFR pathway status (6x wt to mut and 6x mut to wt). Conclusions: Intratumour heterogeneity may explain the EGFR pathway codon changes causing sequencing from single areas of macrodissection to underestimate the tumour genomic landscape and presenting a challenge to personalised medicine. Cetuximab may also drive growth of undetectable mutant clones to detectable levels on pyrosequencing. Clinical trial information: 2007-006701-25.