Associations between AI-Assisted Tumor Amphiregulin and Epiregulin IHC and Outcomes from Anti-EGFR Therapy in the Routine Management of Metastatic Colorectal Cancer

PURPOSE

High tumor production of the EGFR ligands, amphiregulin (AREG) and epiregulin (EREG), predicted benefit from anti-EGFR therapy for metastatic colorectal cancer (mCRC) in a retrospective analysis of clinical trial data. Here, AREG/EREG IHC was analyzed in a cohort of patients who received anti-EGFR therapy as part of routine care, including key clinical contexts not investigated in the previous analysis.

EXPERIMENTAL DESIGN

Patients who received panitumumab or cetuximab ± chemotherapy for treatment of RAS wild-type mCRC at eight UK cancer centers were eligible. Archival formalin-fixed paraffin-embedded tumor tissue was analyzed for AREG and EREG IHC in six regional laboratories using previously developed artificial intelligence technologies. Primary endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 494 of 541 patients (91.3%) had adequate tissue for analysis. A total of 45 were excluded after central extended RAS testing, leaving 449 patients in the primary analysis population. After adjustment for additional prognostic factors, high AREG/EREG expression (n = 360; 80.2%) was associated with significantly prolonged PFS [median: 8.5 vs. 4.4 months; HR, 0.73; 95% confidence interval (CI), 0.56-0.95; P = 0.02] and OS [median: 16.4 vs. 8.9 months; HR, 0.66 95% CI, 0.50-0.86; P = 0.002]. The significant OS benefit was maintained among patients with right primary tumor location (PTL), those receiving cetuximab or panitumumab, those with an oxaliplatin- or irinotecan-based chemotherapy backbone, and those with tumor tissue obtained by biopsy or surgical resection.

CONCLUSIONS

High tumor AREG/EREG expression was associated with superior survival outcomes from anti-EGFR therapy in mCRC, including in right PTL disease. AREG/EREG IHC assessment could aid therapeutic decisions in routine practice. See related commentary by Randon and Pietrantonio, p. 4021.

The clinical relevance of tumor RAS/TP53 dual mutation in early and metastatic colorectal cancer (CRC)

3540

Background: The relevance of individual RAS (KRAS and NRAS) and TP53 mutations in CRC is well described, but the impact of the combination of both mutations together is less understood. RAS/TP53-mutant (mut) patients (pts) were selected in FOCUS 4-C for treatment with Adavosertib (Wee1 inhibitor) due to hypothesised sensitivity due to replication stress and loss of cell cycle checkpoint control. Initial analyses in CRC suggest that RAS/TP53-mut pts may be prognostically distinct from either mutation alone. Here we examine the impact of RAS/TP53-mut status in both early stage and metastatic CRC (mCRC). Methods: RAS and TP53 mutational status were assessed by whole gene targeted NGS or PCR in hotspot regions. Pts with RAS/TP53 status in the following studies were included after exclusion of BRAF-V600E mutants and MSI-H cases: for early-stage, QUASAR2 trial (N = 408) and an Australian community cohort (N = 654); for mCRC, FOCUS (N = 373) and FOCUS4 (N = 721). Biomarker prevalence, clinical characteristics and outcome data in the RAS/TP53-mut group were compared to pts not showing dual RAS/TP53-mut. Results: The prevalence of RAS/TP53-mut was greater in mCRC compared to early CRC (43.9% vs 25.4% respectively, p < 0.001). In early-stage (II & III) cohorts combined, RAS/TP53-mut pts were more likely to be female, have a right-sided primary tumour, and involved lymph nodes. In early CRC RAS/TP53-mut pts had worse outcome: DFS HR = 1.49[1.19-1.88], p = 0.001, and OS HR = 1.48[1.16-1.89], p = 0.001. In FOCUS, RAS/TP53-mut mCRC pts had inferior PFS with 1st line chemotherapy than not dual RAS/TP53-mut: 6.9 vs 8.6 months (HR = 1.44[1.17-1.79], p = 0.001), and also shorter post-progression survival (HR = 1.49, p = 0.001), and overall survival (14.9 vs 18.9 mths [HR = 1.60, p < 0.0005]). Consistently, during 16 weeks of induction chemotherapy for mCRC pts in FOCUS4, 27.4% of RAS/TP53-mut pts had progressive disease, compared with 18.4% in not dual RAS/TP53-mut; PFS from study registration was reduced in RAS/TP53-mut (5.3 vs 6.1 mths;HR = 1.53[1.22-1.94],p < 0.001), but no statistically significant difference in OS (13.6 vs 17.6 mths;HR = 1.27,p = 0.23). Outcomes by each of the four biomarker groups (RAS/TP53 dual mut; RASwt/TP53mut; RASmut/TP53 wt; RAS/TP53 dual wt) will be presented but in all cases the dual mut subgroup had the worst outcomes compared to the other three groups, marginally better than BRAF-V600E CRC. Conclusions: RAS/TP53 dual mutation status provides useful and readily available prognostic information in both early and mCRC, independent of MSI and BRAF status. It is associated with increased risk of recurrence in early CRC, and a higher risk of chemotherapy resistance and inferior outcomes in mCRC. Evaluation of treatment strategies in this sizeable patient group and further understanding of the underlying mechanism of poor outcomes are urgently required.

A biomarker enrichment trial of anti-EGFR agents in right primary tumor location (rPTL), RAS wild-type (RAS-wt) advanced colorectal cancer (aCRC): ARIEL (ISRCTN11061442)

TPS3633

Background: Meta-analysis of 6 RCTs indicates that anti-EGFR agents are ineffective in rPTL RAS-wt aCRC (Arnold D, et al. Ann Oncol. 2017;28:1713-1729). However, data from the phase III PICCOLO and COIN trials suggest high tumor expression of the EGFR ligands, EREG and AREG, confers sensitivity to anti-EGFR agents in a subset of this population (Adams RA, et al. J Clin Oncol. 2012;30(30_suppl):32-32; Seligmann JF, et al. Ann Oncol. 2020;31:1021-1029). More data is needed before ligand assessment can be integrated into routine care: to date, EREG/AREG mRNA has only been assessed retrospectively, and feasibility of timely delivery of results must be demonstrated. The ARIEL trial aims to determine whether first-line chemotherapy plus cetuximab or panitumumab is more effective than chemotherapy alone in achieving early tumor shrinkage (ETS) after 8 weeks of treatment in patients (pts) with EREG/AREG-high rPTL RAS-wt aCRC. Methods: ARIEL is a multicentre, phase IV, open label, biomarker enrichment RCT. Pts with previously untreated rPTL RAS-wt (or RAS-unknown) aCRC are eligible for registration and EREG/AREG assessment using archival FFPE tumor tissue. Those confirmed as RAS-wt EREG/AREG-high (expression above 30th centile based on PICCOLO)3 are eligible for randomization to chemotherapy alone (fluoropyrimidine backbone plus irinotecan or oxaliplatin) vs chemotherapy (FOLFOX or FOLFIRI) plus anti-EGFR therapy (panitumumab or cetuximab) (options at physician’s discretion). Pts with EREG/AREG-low tumors are not eligible for randomization but may consent to translational research and follow-up. The primary endpoint is ETS at 8 weeks (≥30%, yes vs no). Secondary endpoints are depth of response at 16 weeks, overall survival, overall treatment utility, pt-reported quality of life, cost per QALY, pt acceptability of trial procedures, and safety. Pre-trial work-up included cross-validation of the EREG/AREG RT-qPCR assay at trial laboratories in Leeds and Birmingham, UK demonstrating reproducibility of biomarker results. Recruitment to an internal pilot phase is currently ongoing to demonstrate feasibility of timely delivery of biomarker results to sites (lower limit of 90% CI of mean result delivery time for first 20 pts must include 3 weeks). Mean monthly recruitment rate will be assessed at 18 months to determine likelihood of completion of the trial within the 3 year recruitment period. ARIEL is funded by the UK National Institute for Health Research (NIHR) and opened the first of 40 sites in February 2022. 440 pts will be registered for biomarker assessment in order to randomize 162 pts. All pts will be followed-up to 1 year post-randomisation, with a final assessment in all pts when the last pt has completed a year of follow-up (median 3.5 years). ARIEL is participating in the NIHR Associate PI scheme. Clinical trial information: 11061442.

Prognostic and Predictive Impact of Primary Tumor Sidedness for Previously Untreated Advanced Colorectal Cancer

BACKGROUND

Unplanned subgroup analyses from several studies have suggested primary tumor sidedness (PTS) as a potential prognostic and predictive parameter in metastatic colorectal cancer (mCRC). We aimed to investigate the impact of PTS on outcomes of mCRC patients.

METHODS

PTS data of 9277 mCRC patients from 12 first-line randomized trials in the ARCAD database were pooled. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier and Cox models adjusting for age, sex, performance status, prior radiation/chemotherapy, and stratified by treatment arm. Predictive value was tested by interaction term between PTS and treatment (cetuximab plus chemotherapy vs chemotherapy alone). All statistical tests were 2-sided.

RESULTS

Compared with right-sided metastatic colorectal cancer patients (n = 2421, 26.1%), left-sided metastatic colorectal cancer patients (n = 6856, 73.9%) had better OS (median = 21.6 vs 15.9 months; adjusted hazard ratio [HRadj] = 0.71, 95% confidence interval [CI] = 0.67 to 0.76; P < .001) and PFS (median = 8.6 vs 7.5 months; HRadj = 0.80, 95% CI = 0.75 to 0.84; P < .001). Interaction between PTS and KRAS mutation was statistically significant (Pinteraction < .001); left-sidedness was associated with better prognosis among KRAS wild-type (WT) (OS HRadj = 0.59, 95% CI = 0.53 to 0.66; PFS HRadj =0.68, 95% CI = 0.61 to 0.75) but not among KRAS mutated tumors. Among KRAS-WT tumors, survival benefit from anti-EGFR was confirmed for left-sidedness (OS HRadj = 0.85, 95% CI = 0.75 to 0.97; P = .01; PFS HRadj = 0.77, 95% CI = 0.67 to 0.88; P < .001) but not for right-sidedness.

CONCLUSIONS

The prognostic value of PTS is restricted to the KRAS-WT population. PTS is predictive of anti-EGFR efficacy, with a statistically significant improvement of survival for left-sidedness mCRC patients. These results suggest treatment choice in mCRC should be based on both PTS and KRAS status.

Molecular subtype-specific efficacy of anti-EGFR therapy in colorectal cancer is dependent on the chemotherapy backbone

BACKGROUND

Patient selection for addition of anti-EGFR therapy to chemotherapy for patients with RAS and BRAF wildtype metastatic colorectal cancer can still be optimised. Here we investigate the effect of anti-EGFR therapy on survival in different consensus molecular subtypes (CMSs) and stratified by primary tumour location.

METHODS

Retrospective analyses, using the immunohistochemistry-based CMS classifier, were performed in the COIN (first-line oxaliplatin backbone with or without cetuximab) and PICCOLO trial (second-line irinotecan with or without panitumumab). Tumour tissue was available for 323 patients (20%) and 349 (41%), respectively.

RESULTS

When using an irinotecan backbone, anti-EGFR therapy is effective in both CMS2/3 and CMS4 in left-sided primary tumours (progression-free survival (PFS): HR 0.44, 95% CI 0.26-0.75, P = 0.003 and HR 0.12, 95% CI 0.04-0.36, P < 0.001, respectively) and in CMS4 right-sided tumours (PFS HR 0.17, 95% CI 0.04-0.71, P = 0.02). Efficacy using an oxaliplatin backbone was restricted to left-sided CMS2/3 tumours (HR 0.57, 95% CI 0.36-0.96, P = 0.034).

CONCLUSIONS

The subtype-specific efficacy of anti-EGFR therapy is dependent on the chemotherapy backbone. This may provide the possibility of subtype-specific treatment strategies for a more optimal use of anti-EGFR therapy.

Efficacy of Reduced-Intensity Chemotherapy With Oxaliplatin and Capecitabine on Quality of Life and Cancer Control Among Older and Frail Patients With Advanced Gastroesophageal Cancer: The GO2 Phase 3 Randomized Clinical Trial

Importance

Older and/or frail patients are underrepresented in landmark cancer trials. Tailored research is needed to address this evidence gap.

Objective

The GO2 randomized clinical trial sought to optimize chemotherapy dosing in older and/or frail patients with advanced gastroesophageal cancer, and explored baseline geriatric assessment (GA) as a tool for treatment decision-making.

Design, Setting, and Participants

This multicenter, noninferiority, open-label randomized trial took place at oncology clinics in the United Kingdom with nurse-led geriatric health assessment. Patients were recruited for whom full-dose combination chemotherapy was considered unsuitable because of advanced age and/or frailty.

Interventions

There were 2 randomizations that were performed: CHEMO-INTENSITY compared oxaliplatin/capecitabine at Level A (oxaliplatin 130 mg/m2 on day 1, capecitabine 625 mg/m2 twice daily on days 1-21, on a 21-day cycle), Level B (doses 0.8 times A), or Level C (doses 0.6 times A). Alternatively, if the patient and clinician agreed the indication for chemotherapy was uncertain, the patient could instead enter CHEMO-BSC, comparing Level C vs best supportive care.

Main Outcomes and Measures

First, broad noninferiority of the lower doses vs reference (Level A) was assessed using a permissive boundary of 34 days reduction in progression-free survival (PFS) (hazard ratio, HR = 1.34), selected as acceptable by a forum of patients and clinicians. Then, the patient experience was compared using Overall Treatment Utility (OTU), which combines efficacy, toxic effects, quality of life, and patient value/acceptability. For CHEMO-BSC, the main outcome measure was overall survival.

Results

A total of 514 patients entered CHEMO-INTENSITY, of whom 385 (75%) were men and 299 (58%) were severely frail, with median age 76 years. Noninferior PFS was confirmed for Levels B vs A (HR = 1.09 [95% CI, 0.89-1.32]) and C vs A (HR = 1.10 [95% CI, 0.90-1.33]). Level C produced less toxic effects and better OTU than A or B. No subgroup benefited from higher doses: Level C produced better OTU even in younger or less frail patients. A total of 45 patients entered the CHEMO-BSC randomization: overall survival was nonsignificantly longer with chemotherapy: median 6.1 vs 3.0 months (HR = 0.69 [95% CI, 0.32-1.48], P = .34). In multivariate analysis in 522 patients with all variables available, baseline frailty, quality of life, and neutrophil to lymphocyte ratio were independently associated with OTU, and can be combined in a model to estimate the probability of different outcomes.

Conclusions and Relevance

This phase 3 randomized clinical trial found that reduced-intensity chemotherapy provided a better patient experience without significantly compromising cancer control and should be considered for older and/or frail patients. Baseline geriatric assessment can help predict the utility of chemotherapy but did not identify a group benefiting from higher-dose treatment.

Trial Registration

isrctn.org Identifier: ISRCTN44687907.

Artificial Intelligence-Assisted Amphiregulin and Epiregulin IHC Predicts Panitumumab Benefit in RAS Wild-Type Metastatic Colorectal Cancer

PURPOSE

High tumor mRNA levels of the EGFR ligands amphiregulin (AREG) and epiregulin (EREG) are associated with anti-EGFR agent response in metastatic colorectal cancer (mCRC). However, ligand RNA assays have not been adopted into routine practice due to issues with analytic precision and practicality. We investigated whether AREG/EREG IHC could predict benefit from the anti-EGFR agent panitumumab.

EXPERIMENTAL DESIGN

Artificial intelligence algorithms were developed to assess AREG/EREG IHC in 274 patients from the PICCOLO trial of irinotecan with or without panitumumab (Ir vs. IrPan) in RAS wild-type mCRC. The primary endpoint was progression-free survival (PFS). Secondary endpoints were RECIST response rate (RR) and overall survival (OS). Models were repeated adjusting separately for BRAF mutation status and primary tumor location (PTL).

RESULTS

High ligand expression was associated with significant PFS benefit from IrPan compared with Ir [8.0 vs. 3.2 months; HR, 0.54; 95% confidence interval (CI), 0.37-0.79; P = 0.001]; whereas low ligand expression was not (3.4 vs. 4.4 months; HR, 1.05; 95% CI, 0.74-1.49; P = 0.78). The ligand-treatment interaction was significant (P _interaction = 0.02) and remained significant after adjustment for BRAF-mutation status and PTL. Likewise, RECIST RR was significantly improved in patients with high ligand expression (IrPan vs. Ir: 48% vs. 6%; P < 0.0001) but not those with low ligand expression (25% vs. 14%; P = 0.10; P _interaction = 0.01). The effect on OS was similar but not statistically significant.

CONCLUSIONS

AREG/EREG IHC identified patients who benefitted from the addition of panitumumab to irinotecan chemotherapy. IHC is a practicable assay that may be of use in routine practice.

Artificial intelligence-assisted immunohistochemical (IHC) evaluation of tumor amphiregulin (AREG) and epiregulin (EREG) expression as a combined predictive biomarker for panitumumab (Pan) therapy benefit in RAS wild-type (wt) metastatic colorectal cancer (mCRC): Analysis within the phase III PICCOLO trial

111

Background: High tumor mRNA levels of the EGFR ligands, AREG and EREG are associated with anti-EGFR agent response in patients (pts) with RAS-wt mCRC, regardless of tumor location. However, ligand RNA assays have not been adopted into routine clinical practice due to issues with analytical precision and practicality. Here we test whether AREG and EREG expression assessed by IHC can predict benefit from Pan. Methods: A retrospective biomarker study within the PICCOLO trial (NCT00389870; irinotecan [Ir] ± Pan in fluoropyrimidine-resistant RAS-wt mCRC). AREG and EREG positive tumor cells were assessed by IHC in all RAS-wt patients with available tumor tissue. Pathologists annotated tumor areas on digital images of glass slides. Artificial intelligence (AI) algorithms calculated the percentage of tumor cells staining positive for AREG and EREG within the tumor areas. More than 50% AREG and/or EREG tumor cell positivity was regarded as high ligand expression. The primary endpoint was progression-free survival (PFS) and secondary endpoints were RECIST response rate (RR) and overall survival (OS). Results: 274 RAS-wt pts had available tumor tissue. High ligand expression (n = 132) was associated with significant PFS benefit from IrPan compared with Ir (8.0 vs 3.2 months; HR 0.54 [0.37-0.79]; p = 0.001); whereas low ligand expression (n = 142) was not (3.4 vs 4.4 months; HR 1.05 [95% CI, 0.74-1.49]; p = 0.78). The ligand-treatment interaction was significant (p = 0.02) and independent of BRAF-mutation status and primary tumor location. Likewise RR was significantly improved in pts with high ligand expression (IrPan vs Ir: 48% vs 6%; risk ratio, 7.8 [2.90-20.69]; p < 0.0001) but not those with low ligand expression (IrPan vs Ir: 25% vs 14%; risk ratio, 1.8 [95% CI, 0.89-3.65]; p = 0.10) (interaction p = 0.01). Lesser effect was seen on OS. Conclusions: IHC assessment of AREG and EREG identified pts who did or did not benefit from Pan, as has been previously demonstrated through mRNA quantification. IHC represents a more practicable technique as it can be provided at the point of care and is associated with shorter turn-around times. AREG and EREG IHC may be of use in routine practice to identify patients who would benefit from anti-EGFR therapy and those for whom alternative treatment strategies should be explored.

In-depth Clinical and Biological Exploration of DNA Damage Immune Response as a Biomarker for Oxaliplatin Use in Colorectal Cancer

PURPOSE

The DNA damage immune response (DDIR) assay was developed in breast cancer based on biology associated with deficiencies in homologous recombination and Fanconi anemia pathways. A positive DDIR call identifies patients likely to respond to platinum-based chemotherapies in breast and esophageal cancers. In colorectal cancer, there is currently no biomarker to predict response to oxaliplatin. We tested the ability of the DDIR assay to predict response to oxaliplatin-based chemotherapy in colorectal cancer and characterized the biology in DDIR-positive colorectal cancer.

EXPERIMENTAL DESIGN

Samples and clinical data were assessed according to DDIR status from patients who received either 5-fluorouracil (5-FU) or 5FUFA (bolus and infusion 5-FU with folinic acid) plus oxaliplatin (FOLFOX) within the FOCUS trial (n = 361, stage IV), or neoadjuvant FOLFOX in the FOxTROT trial (n = 97, stage II/III). Whole transcriptome, mutation, and IHC data of these samples were used to interrogate the biology of DDIR in colorectal cancer.

RESULTS

Contrary to our hypothesis, DDIR-negative patients displayed a trend toward improved outcome for oxaliplatin-based chemotherapy compared with DDIR-positive patients. DDIR positivity was associated with microsatellite instability (MSI) and colorectal molecular subtype 1. Refinement of the DDIR signature, based on overlapping IFN-related chemokine signaling associated with DDIR positivity across colorectal cancer and breast cancer cohorts, further confirmed that the DDIR assay did not have predictive value for oxaliplatin-based chemotherapy in colorectal cancer.

CONCLUSIONS

DDIR positivity does not predict improved response following oxaliplatin treatment in colorectal cancer. However, data presented here suggest the potential of the DDIR assay in identifying immune-rich tumors that may benefit from immune checkpoint blockade, beyond current use of MSI status.

Immune status is prognostic for poor survival in colorectal cancer patients and is associated with tumour hypoxia

BACKGROUND

Immunohistochemical quantification of the immune response is prognostic for colorectal cancer (CRC). Here, we evaluate the suitability of alternative immune classifiers on prognosis and assess whether they relate to biological features amenable to targeted therapy.

METHODS

Overall survival by immune (CD3, CD4, CD8, CD20 and FOXP3) and immune-checkpoint (ICOS, IDO-1 and PD-L1) biomarkers in independent CRC cohorts was evaluated. Matched mutational and transcriptomic data were interrogated to identify associated biology.

RESULTS

Determination of immune-cold tumours by combined low-density cell counts of CD3, CD4 and CD8 immunohistochemistry constituted the best prognosticator across stage II-IV CRC, particularly in patients with stage IV disease (HR 1.98 [95% CI: 1.47-2.67]). These immune-cold CRCs were associated with tumour hypoxia, confirmed using CAIX immunohistochemistry (P = 0.0009), which may mediate disease progression through common biology (KRAS mutations, CRIS-B subtype and SPP1 mRNA overexpression).

CONCLUSIONS

Given the significantly poorer survival of immune-cold CRC patients, these data illustrate that assessment of CD4-expressing cells complements low CD3 and CD8 immunohistochemical quantification in the tumour bulk, potentially facilitating immunophenotyping of patient biopsies to predict prognosis. In addition, we found immune-cold CRCs to associate with a difficult-to-treat, poor prognosis hypoxia signature, indicating that these patients may benefit from hypoxia-targeting clinical trials.

Colorectal cancer peritoneal metastases: Biology, treatment and next steps

The presence of peritoneal metastases in patients with advanced colorectal cancer is associated with poor prognosis but the mechanisms for this are unclear. This review summarises the current knowledge of the pathophysiology, clinical features, prevalence, prognosis, and molecular biology of peritoneal metastases and the risk factors for the development of peritoneal metastases following resection of a primary colorectal tumour. Furthermore, the evidence for treatment strategies are described including cytoreductive surgery, hyperthermic intraperitoneal chemotherapy, early post-operative intraperitoneal chemotherapy, sequential post-operative intraperitoneal chemotherapy and emerging novel strategies. Active areas of research should include the identification of individuals at high risk of peritoneal metastases after curative resection of primary tumour, development of a surveillance program for high-risk patients, optimisation of systematic therapies and further investigation of the use of intraperitoneal chemotherapy.

Evaluation of Continuous Tumor-Size-Based End Points as Surrogates for Overall Survival in Randomized Clinical Trials in Metastatic Colorectal Cancer

IMPORTANCE

Tumor measurements can be used to estimate time to nadir and depth of nadir as potential surrogates for overall survival (OS).

OBJECTIVE

To assess time to nadir and depth of nadir as surrogates for OS in metastatic colorectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

Pooled analysis of 20 randomized clinical trials within the Aide et Recherche en Cancerologie Digestive database, which contains academic and industry-sponsored trials, was conducted. Three sets of comparisons were performed: chemotherapy alone, antiangiogenic agents, and anti-epidermal growth factor receptor agents in first-line treatment for patients with metastatic colorectal cancer.

MAIN OUTCOMES AND MEASURES

Surrogacy of time to nadir and depth of nadir was assessed at the trial level based on joint modeling of relative tumor-size change vs baseline and OS. Treatment effects on time to nadir and on depth of nadir were defined in terms of between-arm differences in time to nadir and in depth of nadir, and both were assessed in linear regressions for their correlation with treatment effects (hazard ratios) on OS within each set. The strengths of association were quantified using sample-size-weighted coefficients of determination (R2), with values closer to 1.00 indicating stronger association. At the patient level, the correlation was assessed between modeled relative tumor-size change and OS.

RESULTS

For 14 chemotherapy comparisons in 4289 patients, the R2 value was 0.63 (95% CI, 0.30-0.96) for the association between treatment effects on time to nadir and OS and 0.08 (95% CI, 0-0.37) for depth of nadir and OS. For 11 antiangiogenic agent comparisons (4854 patients), corresponding values of R2 were 0.25 (95% CI, 0-0.72) and 0.06 (95% CI, 0-0.35). For 8 anti-epidermal growth factor receptor comparisons (2684 patients), corresponding values of R2 were 0.24 (95% CI, 0-0.83) and 0.21 (95% CI, 0-0.78).

CONCLUSIONS AND RELEVANCE

In contrast with early reports favoring depth of response as a surrogate, these results suggest that neither time to nadir nor depth of nadir is an acceptable surrogate for OS in the first-line treatment of metastatic colorectal cancer.

FOxTROT: an international randomised controlled trial in 1052 patients (pts) evaluating neoadjuvant chemotherapy (NAC) for colon cancer

3504

Background: NAC is well established in many solid tumours but has not undergone large-scale evaluation in colon cancer. Methods: Pts had operable, non-obstructed colon cancer; CT-predicted stage T3-4, N0-2, M0, and were fit for FOLFOX and surgery. They were randomised 2:1 to the novel sequence (6 wk FOLFOX NAC, then surgery, then 18 wk FOLFOX) or control (surgery then 24 wk FOLFOX). RAS-wt pts allocated to the novel arm could optionally be sub-randomized 1:1 to ± panitumumab (pan) during the NAC phase. Two "dealer’s choices" allowed total chemo duration 12 wk instead of 24 (in older/low-risk pts) and OxCap in place of FOLFOX (except in pts randomized ± pan). Primary endpoint is freedom from recurrent or persistent disease after 2 yrs, by ITT. Secondary endpoints include safety, histological stage, completeness of resection, OS. Results: 1052 pts were randomised, Jun 2008-Dec 2016, at 85 centres in UK, Denmark and Sweden. Conclusions: NAC was well tolerated and safe, with no increase in perioperative morbidity and a trend toward fewer serious postoperative complications. Evidence of histological regression was seen in 59% pts after NAC, including some pCRs. This resulted in marked histological downstaging and a halving of the rate of incomplete resections. We observed an improvement in 2-yr failure rate (HR=0.77), but this fell short of statistical significance (p=0.11). NAC for colon cancer improves surgical outcomes and can now be considered as a treatment option; longer follow-up and further trials are required to confirm the long-term benefits, refine its use and optimise case selection. Clinical trial information: 87163246. [Table: see text]

Best supportive care (BSC) with or without low-dose chemotherapy (chemo) in frail elderly patients with advanced gastroesophageal cancer (aGOAC): The uncertain randomization of the GO2 phase III trial

4051

Background: Before 2000, trials comparing BSC +/- chemo for aGOAC showed overall survival (OS) benefit, but in predominantly fit patients (pts). We have revisited this question in a modern context, using low-dose chemo in a frail population, with comprehensive baseline health and frailty assessment. Methods: In the GO2 trial, elderly and/or frail aGOAC pts with a “certain” indication for chemo were randomised between 3 chemo doses. In this GO2 substudy, pts with an “uncertain” indication for chemo were instead randomised to BSC ± the lowest dose chemo. Pts were eligible if clinician and pt agreed the indication for chemo was uncertain. There was no PS threshold, but eGFR ≥30 and bili < 2xULN were required. Baseline assessment included global QL, symptom & functional scales, frailty and comorbidity. Randomisation was 1:1 to BSC alone, or with oxaliplatin 78 mg/m2 d1, capecitabine 375 mg/m2 bd d1-21 (modified if eGFR 30-50 ml/min or bili 1.5-2.0 xULN), q21d. QL was reassessed after 9 and 18 wks. The primary endpoint analysis was OS, adjusted for baseline factors. The sample size for this exploratory sub-study was not pre-set, but around 60 pts were anticipated. Results: 558 pts entered GO2 at 61 centres 2014-17, of whom only 45 pts (8%) at 21 centres entered this uncertain randomisation. This would provide 80% power at p = 0.05 (2-tailed) to detect an OS HR of 0.3. OS was shorter in pts with worse baseline PS (p<0.01) or distant mets (p<0.05). OS was not significantly improved with chemo; however we cannot exclude HR >0.32. QL deteriorated less with BSC+chemo than with BSC alone. Conclusions: In this frail, poor PS population, we observed a small survival benefit with chemo but this did not reach statistical significance. Clinicians should carefully consider BSC alone as a valid treatment option for aGOAC pts with poor PS and/or frailty. Clinical trial information: 44687907. [Table: see text]

Optimizing chemotherapy for frail and elderly patients (pts) with advanced gastroesophageal cancer (aGOAC): The GO2 phase III trial

4006

Background: Many pts with aGOAC are elderly and/or frail. We previously compared epirubin/ oxaliplatin/ capecitabine (EOCap) vs OCap vs Cap in a pick-the-winner study and found OCap best. GO2 was designed to find the optimum dose of OCap and to explore the use of an objective baseline geriatric assessment to individualize doses for maximum Overall Treatment Utility (OTU), a composite of clinical benefit, tolerability, QL and patient value. Methods: Pts with aGOAC were eligible if unsuitable for full-dose EOCap due to age or frailty, but fit for OCap; GFR ≥ 30, bili <2x ULN. Baseline assessment included global QL; symptoms; functional scales; comorbidity; frailty. Randomization was 1:1:1 to dose Level A (Ox 130 mg/m2d1, Cap 625 mg/m2bd d1-21, q21d), B (80% Level A doses) or C (60% Level A doses). Pts with GFR 30-50 ml/min or bili 1.5-2.0 xULN received 75% of the allocated dose of Cap. At 9 wks, pts were scored for OTU. Continuation thereafter was based on clinical judgement. Non-inferiority (vs A) was assessed using PFS censored at 12 months, with boundary HR 1.34 (based on discussion with pts and clinicians), needing 284 PFS events per 2-way comparison. Baseline fitness was assessed as predictive of OTU, overall and by interaction with dose level. Results: 514 pts were randomised, 2014-17, at 61 UK centres. Clinical trial information: 44687907. Non-inferiority of PFS is confirmed for Level B vs A (HR 1.09, CI 0.89-1.32) and for Level C vs A (HR 1.10, CI 0.90-1.33). Level C pts had less toxicity and better OTU outcomes than A or B. When analysed by baseline age, frailty and PS, Level C produced the best OTU even in younger, less frail and better PS patients; no group was identified who benefit more from the higher dose levels. Conclusions: This is the largest RCT to date specifically investigating frail and/or elderly aGOAC pts, and should guide future treatment. The lowest dose tested was non-inferior in terms of PFS and produced less toxicity and better overall treatment utility.[Table: see text]

Choosing the right strategy based on individualized treatment effect predictions: combination versus sequential chemotherapy in patients with metastatic colorectal cancer

BACKGROUND

Translating results from randomized trials to individual patients is challenging, since treatment effects may vary due to heterogeneous prognostic characteristics. We aimed to demonstrate model development for individualized treatment effect predictions in cancer patients. We used data from two randomized trials that investigated sequential versus combination chemotherapy in unresectable metastatic colorectal cancer (mCRC) patients.

MATERIAL AND METHODS

We used data from 803 patients included in CAIRO for prediction model development and internal validation, and data from 1423 patients included in FOCUS for external validation. A Weibull model with pre-specified patient and tumour characteristics was developed for a prediction of gain in median overall survival (OS) by upfront combination versus sequential chemotherapy. Decision curve analysis with net benefit was used. A nomogram was built using logistic regression for estimating the probability of receiving second-line treatment after the first-line monochemotherapy.

RESULTS

Median-predicted gain in OS for the combination versus sequential chemotherapy was 2.3 months (IQR: -1.1 to 3.7 months). A predicted gain in favour of sequential chemotherapy was found in 231 patients (29%) and a predicted gain of >3 months for combination chemotherapy in 294 patients (37%). Patients with benefit from sequential chemotherapy had metachronous metastatic disease and a left-sided primary tumour. Decision curve analyses showed improvement in a net benefit for treating all patients according to prediction-based treatment compared to treating all patients with combination chemotherapy. Multiple characteristics were identified as prognostic variables which identify patients at risk of never receiving second-line treatment if treated with initial monochemotherapy. External validation showed good calibration with moderate discrimination in both models (C-index 0.66 and 0.65, respectively).

CONCLUSIONS

We successfully developed individualized prediction models including prognostic characteristics derived from randomized trials to estimate treatment effects in mCRC patients. In times where the heterogeneity of CRC becomes increasingly evident, such tools are an important step towards personalized treatment.

Clinicopathological differences and survival outcomes with first-line therapy in patients with left-sided colon cancer and rectal cancer: Pooled analysis of 2879 patients from AGITG (MAX), COIN, FOCUS2, OPUS, CRYSTAL and COIN-B trials in the ARCAD database

PURPOSE

Patients with left-sided colon tumours have better survival and respond differently to biologics compared with patients with right-sided tumours. Left-sided colon tumours and rectal cancers are often grouped together. Herein, we examined the clinicopathological differences and outcomes between left-sided colon and rectal cancers.

PATIENTS AND METHODS

Data from 2879 metastatic colorectal cancer patients enrolled on six first-line clinical trials during 2004-2010 were pooled. Patients were included if the primary tumour origin was clearly defined. Progression-free survival (PFS) and overall survival (OS) were compared in the two groups after adjusting for patient and tumour characteristics, metastatic sites and the first-line regimen.

RESULTS

In total, 1374 patients with metastatic left-sided colon cancer and 1505 patients with metastatic rectal cancers were evaluated. Left-sided colon cancer patients were more likely to be female (40.1% versus 32.6%; P < 0.0001) and older (31.0% ≥ 70 years versus 25.8%; P = 0.0033) compared with rectal cancers patients. Patients with left-sided colon cancer had higher rates of liver metastases (80.9% versus 72.3%, P < 0.0001) but lower rates of lung metastases (34.2% versus 53.8%, P < 0.0001). KRAS mutations were slightly less frequent among left-sided tumours (34.8% versus 40.5%; P = 0.0103). Patients with left-sided tumours had approximately similar PFS (median 7.4 versus 6.9 months; hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.87-1.03; P = 0.1998) and OS (median 17.4 versus 16.6 months; HR 0.99, 95% CI 0.91-1.07; P = 0.7597) compared with rectal cancer patients.

CONCLUSION

The site of tumour origin within the left side was not prognostic of outcomes. Moreover, neither bevacizumab nor cetuximab impacted, differently, the findings of the comparisons in outcomes between patients with left-sided colon tumours or rectal cancers.

Personalizing Survival Predictions in Advanced Colorectal Cancer: The ARCAD Nomogram Project

Background

Estimating prognosis on the basis of clinicopathologic factors can inform clinical practice and improve risk stratification for clinical trials. We constructed prognostic nomograms for one-year overall survival and six-month progression-free survival in metastatic colorectal carcinoma by using the ARCAD database.

Methods

Data from 22 674 patients in 26 randomized phase III clinical trials since 1997 were used to construct and validate Cox models, stratified by treatment arm within each study. Candidate variables included baseline age, sex, body mass index, performance status, colon vs rectal cancer, prior chemotherapy, number and location of metastatic sites, tumor mutation status (BRAF, KRAS), bilirubin, albumin, white blood cell count, hemoglobin, platelets, absolute neutrophil count, and derived neutrophil-to-lymphocyte ratio. Missing data (<11%) were imputed, continuous variables modeled with splines, and clinically relevant pairwise interactions tested if P values were less than .001. Final models were internally validated via bootstrapping to obtain optimism-corrected calibration and discrimination C-indices, and externally validated on a 10% holdout sample from each trial (n = 2257).

Results

In final models, all included variables were associated with overall survival except for lung metastases, and all but total white cell count associated with progression-free survival. No clinically relevant pairwise interactions were identified. Final nomogram calibration was good (C = 0.68 for overall and C = 0.62 for progression-free survival), as was external validity (concordance between predicted >50% vs < 50% probability) and actual (yes/no) survival (72.8% and 68.2% concordance, respectively, for one-year overall and six-month progression-free survival, between predicted [>50% vs < 50% probability] and actual [yes/no] overall and progression-free survival). Median survival predictions fell within the actual 95% Kaplan-Meier confidence intervals.

Conclusions

The nomograms are well calibrated and internally and externally valid. They have the potential to aid prognostication and patient-physician communication and balance risk in colorectal cancer trials.

Association of Tumor HER3 Messenger RNA Expression With Panitumumab Efficacy in Advanced Colorectal Cancer

IMPORTANCE

Epidermal growth factor receptor (EGFR) (HER1) signaling depends on ligand binding and dimerization with itself or other HER receptors. We previously showed in a randomized trial that high EGFR ligand expression is predictive of panitumumab benefit in advanced colorectal cancer. Tumor expression of HER3 may further refine the RAS wild-type (wt) population benefitting from anti-EGFR agents.

OBJECTIVE

To examine HER3 messenger RNA expression as a prognostic and predictive biomarker for anti-EGFR therapy in a randomized clinical trial of panitumumab.

DESIGN, SETTING, AND PARTICIPANTS

The study was a prospectively planned retrospective biomarker study of pretreatment samples from the PICCOLO trial that tested the addition of panitumumab to irinotecan therapy in patients with KRAS wt advanced colorectal cancer who experienced failure with prior fluoropyrimidine treatment. HER3 was assessed as a prognostic marker, then as a predictive biomarker in patients with RAS wt, first as a continuous variable and then as a binary (high vs low) variable. Relationship with MEK-AKT pathway mutations and EGFR ligands epiregulin and amphiregulin (EREG/AREG) were also assessed.

MAIN OUTCOMES AND MEASURES

Primary end point was progression-free survival (PFS); secondary end points were response rate and overall survival (OS).

RESULTS

In 308 patients (mean age at randomization, 61.6 years; 193 men) higher HER3 was weakly prognostic for OS (hazard ratio [HR] per 2-fold change, 0.91; 95% CI, 0.83-0.99; P = .04) but not PFS (HR, 0.93; 95% CI, 0.83-1.05; P = .25). Higher HER3 was predictive, being associated with prolonged PFS on irinotecan plus panitumumab (IrPan) (HR, 0.71; 95% CI, 0.61-0.82; P < .001), but not irinotecan (HR, 0.96; 95% CI, 0.82-1.13; P = .65) in patients with RAS wt, with significant interaction between biomarker and treatment (P = .001). Similar interaction was seen for OS (P = .004). In an exploratory binary model, dividing the population at the 66th percentile, HER3 was predictive of panitumumab benefit: in patients with high HER3 expression, median PFS was 8.2 months (IrPan) vs 4.4 months (irinotecan) (HR, 0.33; 95% CI, 0.19-0.58; P < .001). Patients with low HER3 expression gained no benefit in PFS: 3.3 months (IrPan) vs 4.3 months (irinotecan) (HR, 0.96; 95% CI, 0.67-1.38; P = .84), with significant interaction (P = .002). The binary model was also predictive for OS, with significant interaction (P = .01). Combining HER3 and ligand data, patients with HER3-high, AREG/EREG-high tumors gained markedly from panitumumab (PFS HR, 0.24; 95% CI, 0.11-0.51; P < .005 and OS HR, 0.36; 95% CI, 0.18-0.73; P = .004). Conversely, patients with HER3-low, AREG/EREG-low tumors did not benefit (PFS HR, 1.14; 95% CI, 0.73-1.79; P = .57 and OS HR, 1.44; 95% CI, 0.92-2.26; P = .11).

CONCLUSIONS AND RELEVANCE

High HER3 expression identified patients with RAS wt who gained markedly from panitumumab, and those who did not, with statistically significant biomarker-treatment interactions for PFS and OS. This finding provides insight into the mechanism of anti-EGFR agents and is of potential clinical utility.

Associations of incidence of common adverse events (AEs) and survival outcomes in metastatic colorectal cancer (mCRC) patients (pts) treated with first line chemotherapy: Findings from 9,812 pts in the ARCAD database

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Background: There is limited, often conflicting evidence about AE timing, severity or associations with outcomes with the use of cytotoxic agents in cancer treatment. We investigated the impact on overall survival (OS) and progression-free survival (PFS) of selected common AEs (neutropenia, diarrhea, nausea, vomiting, neuropathy) occurring in patients receiving first line oxaliplatin (Oxa)- and/or irinotecan(Iri)-based regimens for mCRC. Methods: The CTCAE grading scores of at least one AE of interest were available on 9812 pts treated with chemotherapy alone (median age 63; 62.4% male, 50.1% ECOG PS 0) from 17 1st-line randomized trials. Patients who also received biologics were excluded in the primary analyses. AEs occurring during the first 6 weeks of treatment and entire treatment were analyzed by stratified multivariable Cox models in relationship to OS/PFS. 55.7% pts received Oxa- regimens, 35.7% Iri-regimens, and 8.6% combined Oxa- and Iri-regimens. Results: Within the first 6 weeks of treatment, G3+ neutropenia (HRadj= 1.3, 95% CI, 1.06-1.59, padj 0.01), diarrhea (HRadj= 1.48, 95% CI, 1.23-1.79, padj < .0001), nausea (HRadj= 1.53, 95% CI, 1.17-1.99, padj 0.002) and vomiting (HRadj= 1.56, 95% CI, 1.18-2.07, padj 0.002) were associated with significantly worse OS for Iri-regimens, but only G3+ nausea predicted for worse OS for Oxa- regimens (HRadj= 1.61, 95% CI, 1.18-2.21, padj 0.003). For AEs experienced at any time, G3+ neutropenia and neuropathy were significantly associated with longer PFS and OS for Oxa-regimens, while G3+ vomiting and nausea were associated with worse OS for both Oxa- and Iri-based regimens. Sensitivity analysis showed largely concordant results by including pts who also received biologics. Conclusions: The association between more severe selected AEs and outcome varies between AEs and is influenced by timing of the occurrence. More severe selected AEs occurring early in treatment are associated with worse outcomes. In contrast, for AEs occurring at any time, G3+ neutropenia and neuropathy predicted for longer PFS and/or OS in Oxa-treated pts.

Decoy receptor 1 (DCR1) promoter hypermethylation and response to irinotecan in metastatic colorectal cancer

Diversity in colorectal cancer biology is associated with variable responses to standard chemotherapy. We aimed to identify and validate DNA hypermethylated genes as predictive biomarkers for irinotecan treatment of metastatic CRC patients.

Candidate genes were selected from 389 genes involved in DNA Damage Repair by correlation analyses between gene methylation status and drug response in 32 cell lines. A large series of samples (n=818) from two phase III clinical trials was used to evaluate these candidate genes by correlating methylation status to progression-free survival after treatment with first-line single-agent fluorouracil (Capecitabine or 5-fluorouracil) or combination chemotherapy (Capecitabine or 5-fluorouracil plus irinotecan (CAPIRI/FOLFIRI)).

In the discovery (n=185) and initial validation set (n=166), patients with methylated Decoy Receptor 1 (DCR1) did not benefit from CAPIRI over Capecitabine treatment (discovery set: HR=1.2 (95%CI 0.7-1.9, p=0.6), validation set: HR=0.9 (95%CI 0.6-1.4, p=0.5)), whereas patients with unmethylated DCR1 did (discovery set: HR=0.4 (95%CI 0.3-0.6, p=0.00001), validation set: HR=0.5 (95%CI 0.3-0.7, p=0.0008)). These results could not be replicated in the external data set (n=467), where a similar effect size was found in patients with methylated and unmethylated DCR1 for FOLFIRI over 5FU treatment (methylated DCR1: HR=0.7 (95%CI 0.5-0.9, p=0.01), unmethylated DCR1: HR=0.8 (95%CI 0.6-1.2, p=0.4)).

In conclusion, DCR1 promoter hypermethylation status is a potential predictive biomarker for response to treatment with irinotecan, when combined with capecitabine. This finding could not be replicated in an external validation set, in which irinotecan was combined with 5FU. These results underline the challenge and importance of extensive clinical evaluation of candidate biomarkers in multiple trials.

Clinical Calculator for Early Mortality in Metastatic Colorectal Cancer: An Analysis of Patients From 28 Clinical Trials in the Aide et Recherche en Cancérologie Digestive Database

Purpose Factors contributing to early mortality after initiation of treatment of metastatic colorectal cancer are poorly understood. Materials and Methods Data from 22,654 patients enrolled in 28 randomized phase III trials contained in the ARCAD (Aide et Recherche en Cancérologie Digestive) database were pooled. Multivariable logistic regression models for 30-, 60-, and 90-day mortality were constructed, including clinically and statistically significant patient and disease factors and interaction terms. A calculator (nomogram) for 90-day mortality was developed and validated internally using bootstrapping methods and externally using a 10% random holdout sample from each trial. The impact of early progression on the likelihood of survival to 90 days was examined with time-dependent Cox proportional hazards models. Results Mortality rates were 1.4% at 30 days, 3.4% at 60 days, and 5.5% at 90 days. Among baseline factors, advanced age, lower body mass index, poorer performance status, increased number of metastatic sites, BRAF mutant status, and several laboratory parameters were associated with increased likelihood of early mortality. A multivariable model for 90-day mortality showed strong internal discrimination (C-index, 0.77) and good calibration across risk groups as well as accurate predictions in the external validation set, both overall and within patient subgroups. Conclusion A validated clinical nomogram has been developed to quantify the risk of early death for individual patients during initial treatment of metastatic colorectal cancer. This tool may be used for patient eligibility assessment or risk stratification in future clinical trials and to identify patients requiring more or less aggressive therapy and additional supportive measures during and after treatment.

A randomised phase II trial and feasibility study of palliative chemotherapy in frail or elderly patients with advanced gastroesophageal cancer (321GO)

BACKGROUND

Elderly patients are commonly under-represented in cancer clinical trials. The 321GO was undertaken in preparation for a definitive phase three trial assessing different chemotherapy regimens in a frail and/or elderly population with advanced gastroesophageal (GO) cancer.

METHODS

Patients with advanced GO cancer considered unfit for conventional dose chemotherapy were randomly assigned in a 1 : 1 : 1 ratio to: epirubicin, oxaliplatin and capecitabine (EOX); oxaliplatin and capecitabine (OX); and capecitabine alone (X) (all 80% of full dose and unblinded). The primary end point was patient recruitment over an 18-month period. A registration study recorded treatment choice for all patients with advanced GO cancer at trial centres.

RESULTS

A total of 313 patients were considered for palliative chemotherapy for GO cancer over the 18-month period: 115 received full dose treatment, 89 less than standard treatment or entered 321GO and 111 no treatment. Within 321GO, 55 patients were randomly assigned (19 to OX and X; 17 to EOX). Progression-free survival (PFS) for all patients was 4.4 months and by arm 5.4, 5.6 and 3.0 months for EOX, OX and X, respectively. The number of patients with a good overall treatment utility (OTU), a novel patient-centred endpoint, at 12 weeks was 3 (18%), 6 (32%) and 1 (6%) for EOX, OX and X, respectively. At 6 weeks, 22 patients (41%) had experienced a non-haematologic toxicity ⩾grade 3, most commonly lethargy or diarrhoea. The OTU was prognostic for overall survival in patients alive at week 12 (logrank test P=0.0001).

CONCLUSIONS

It is feasible to recruit elderly and/or frail patients with advanced GO cancer to a randomised clinical trial. The OX is the preferred regimen for further study. Overall treatment utility shows promise as a comparator between treatment regimens for feasibility and randomised trials in the elderly and/or frail GO cancer population.

Rectal versus left-sided colon cancers: Clinicopathological differences observed in a pooled analysis of 4,182 patients enrolled to 8 clinical trials from the ARCAD database

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Background: Recent retrospective analysis of CALGB/SWOG 80405 showed that left-sided colon cancers (LCC) respond differently to biological therapy compared with right-sided tumors. However, differences between rectal cancers (RC) and LCC remain undefined. Herein, we report our exploration of differences between these two groups. Methods: Individual patient data from 4182 patients (pts) with metastatic colorectal cancers, enrolled onto 8 first-line randomized trials, were pooled. Only pts with tumor locations that were clearly defined as LCC (splenic flexure to sigmoid) or RC were included in this analysis. Differences in pt characteristics and disease factors according to LCC vs. RC were identified. The prognostic effect of primary tumor location on OS and PFS was quantified via multivariable Cox proportional hazards modeling stratified by treatment arm within each study and adjusting for age, sex, performance status, and prior surgery. Results: In total, 2,479 (59%) pts with LCC and 1,703 (41%) pts with RC were identified. Pts with RC, compared with LCC, were more likely to be male (68% vs. 62%, p < 0.001), have lung metastases (mets) (56% vs. 37%, p < 0.001), and have 2 or more metastatic sites (64% vs. 60%, p < 0.02), whereas pts with LCC were more likely to have liver mets (84% vs. 76%, p < 0.001). RC had a greater frequency of KRAS mutations (41% vs. 37%, p = 0.04) than LCC but there were no differences in the frequency of BRAF mutations (5% vs. 4%, p = 0.2). In multivariable analysis, no differences in OS or PFS were observed between pts with LCC vs. RC. While risk of death did not differ by primary tumor location, across all pts with LCC or RC, those with liver mets had a 17% increased risk of death compared to those with lung mets (HR = 1.17, p = 0.03) after adjusting for effects of other variables. Forthcoming prognostic analysis of LCC vs. RC within grouped backbone treatments (e.g., FOLFOX and FOLFIRI) is underway. Conclusions: Tumors arising in the rectum may carry clinical and molecular features that are distinct from LCC. Further investigations are warranted to determine whether RC should be treated with the same chemo backbone and biological therapy as LCC.

Prognosis of patients with peritoneal metastatic colorectal cancer given systemic therapy: an analysis of individual patient data from prospective randomised trials from the Analysis and Research in Cancers of the Digestive System (ARCAD) database

BACKGROUND

Patients with peritoneal metastatic colorectal cancer have reduced overall survival compared with patients with metastatic colorectal cancer without peritoneal involvement. Here we further investigated the effect of the number and location of metastases in patients receiving first-line systemic chemotherapy.

METHODS

We analysed individual patient data for previously untreated patients enrolled in 14 phase 3 randomised trials done between 1997 and 2008. Trials were included if protocols explicitly pre-specified and solicited for patients with peritoneal involvement in the trial data collection process or had done a formal peritoneum-focused review of individual pre-treatment scans. We used stratified multivariable Cox models to assess the prognostic associations of peritoneal metastatic colorectal cancer with overall survival and progression-free survival, adjusting for other key clinical-pathological factors (age, sex, Eastern Cooperative Oncology Group (ECOG) performance score, primary tumour location [colon vs rectum], previous treatment, and baseline BMI). The primary endpoint was difference in overall survival between populations with and without peritoneal metastases.

FINDINGS

Individual patient data were available for 10 553 patients. 9178 (87%) of 10 553 patients had non-peritoneal metastatic colorectal cancer (4385 with one site of metastasis, 4793 with two or more sites of metastasis), 194 (2%) patients had isolated peritoneal metastatic colorectal cancer, and 1181 (11%) had peritoneal metastatic colorectal cancer and other organ involvement. These groups were similar in age, ethnic origin, and use of targeted treatment. Patients with peritoneal metastatic colorectal cancer were more likely than those with non-peritoneal metastatic colorectal cancer to be women (565 [41%] of 1371 vs 3312 [36%] of 9169 patients; p=0·0003), have colon primary tumours (1116 [84%] of 1334 patients vs 5603 [66%]; p<0·0001), and have performance status of 2 (136 [10%] vs 521 [6%]; p<0·0001). We recorded a higher proportion of patients with mutated BRAF in patients with peritoneal-only (eight [18%] of 44 patients with available data) and peritoneal metastatic colorectal cancer with other sites of metastasis (34 [12%] of 289), compared with patients with non-peritoneal metastatic colorectal cancer (194 [9%] of 2230; p=0·028 comparing the three groups). Overall survival (adjusted HR 0·75, 95% CI 0·63-0·91; p=0·003) was better in patients with isolated non-peritoneal sites than in those with isolated peritoneal metastatic colorectal cancer. Overall survival of patients with two of more non-peritoneal sites of metastasis (adjusted HR 1·04, 95% CI 0·86-1·25, p=0.69) and those with peritoneal metastatic colorectal cancer plus one other site of metastasis (adjusted HR 1·10, 95% CI 0·89-1·37, p=0·37) was similar to those with isolated peritoneal metastases. Compared with patients with isolated peritoneal metastases, those with peritoneal metastases and two or more additional sites of metastasis had the shortest survival (adjusted HR 1·40; CI 1·14-1·71; p=0·0011).

INTERPRETATION

Patients with peritoneal metastatic colorectal cancer have significantly shorter overall survival than those with other isolated sites of metastases. In patients with several sites of metastasis, poor survival is a function of both increased number of metastatic sites and peritoneal involvement. The pattern of metastasis and in particular, peritoneal involvement, results in prognostic heterogeneity of metastatic colorectal cancer.

FUNDING

None.

Combined Epiregulin and Amphiregulin Expression Levels as a Predictive Biomarker for Panitumumab Therapy Benefit or Lack of Benefit in Patients With RAS Wild-Type Advanced Colorectal Cancer

IMPORTANCE

RAS wild-type (wt) status is necessary but not sufficient for response to anti-epidermal growth factor receptor (EGFR) agents in advanced colorectal cancer (aCRC). RNA expression of EGFR ligands epiregulin (EREG) and amphiregulin (AREG) may correlate with EGFR-targeted therapy efficacy in aCRC, so may represent a much-needed additional predictive marker for these drugs.

OBJECTIVE

To examine a novel ligand model in a randomized clinical trial of panitumumab, irinotecan, and ciclosporin in colorectal cancer (PICCOLO) with with the a priori hypothesis that high tumor expression of either AREG or EREG would predict panitumumab therapy benefit in RAS-wt patients; and low expression, lack of efficacy.

DESIGN, SETTING, AND PARTICIPANTS

Prospectively planned retrospective biomarker study from the PICCOLO trial, which tested the addition of panitumumab to irinotecan therapy in patients with KRAS wt aCRC who experienced failure with prior fluoropyrimidine treatment. The analysis was conducted between 2012 and 2014. A predefined dichotomous model classified tumors as "high expressor" (either EREG or AREG in top tertile for messenger RNA level) or "low expressor" (neither EREG nor AREG in top tertile). Ligand expression was assessed as a prognostic and predictive biomarker. Expression of AREG/EREG and RAS and BRAF mutations were assessed in archival tumor tissue.

MAIN OUTCOMES AND MEASURES

Primary end point was progression-free survival (PFS); secondary end points were response rate and overall survival (OS).

RESULTS

Of the 696 PICCOLO trial patients in the irinotecan-vs-irinotecan with panitumumab randomization, 331 had sufficient tumor tissue available and measurement of ligand expression was successful in 323. High ligand expression was not prognostic for OS (hazard ratio [HR], 0.79 [95% CI, 0.58-1.09]; P = .15) or PFS (HR, 0.93 [95% CI, 0.68-1.27]; P = .64). The primary population had RAS wt aCRC (n = 220); for RAS wt patients with high ligand expression, median (interquartile range [IQR]) PFS was 8.3 [4.0-11.0] months (irinotecan with panitumumab) vs 4.4 [2.8-6.7] months (irinotecan alone); HR, 0.38 [95% CI, 0.24-0.61]; P < .001). In RAS wt patients with low ligand expression, median (IQR) PFS was 3.2 [2.7-8.1] months (irinotecan with panitumumab) vs 4.0 [2.7-7.5] months (irinotecan); HR, 0.93 [95% CI, 0.64-1.37]; P = .73; interaction test results were significant [P = .01]). Less marked effects were seen for response rate (interaction P = .17) and OS (interaction P = .11).

CONCLUSIONS AND RELEVANCE

High ligand expression is a predictive marker for panitumumab therapy benefit on PFS in RAS wt patients; conversely, patients with low ligand expression gained no benefit. The current "opt-in" strategy for anti-EGFR therapy in all patients with RAS wt aCRC should be questioned. Expression of EREG/AREG is a useful biomarker for anti-EGFR therapy; optimization for clinical use is indicated.

TRIAL REGISTRATION

isrctn Identifier: ISRCTN93248876.

Body Mass Index Is Prognostic in Metastatic Colorectal Cancer: Pooled Analysis of Patients From First-Line Clinical Trials in the ARCAD Database

PURPOSE

In recent retrospective analyses of early-stage colorectal cancer (CRC), low and high body mass index (BMI) scores were associated with worsened outcomes. Whether BMI is a prognostic or predictive factor in metastatic CRC (mCRC) is unclear.

PATIENTS AND METHODS

Individual data from 21,149 patients enrolled onto 25 first-line mCRC trials during 1997 to 2012 were pooled. We assessed both prognostic and predictive effects of BMI on overall survival and progression-free survival, and we accounted for patient and tumor characteristics and therapy type (targeted v nontargeted).

RESULTS

BMI was prognostic for overall survival (P < .001) and progression-free survival (P < .001), with an L-shaped pattern. That is, risk of progression and/or death was greatest for low BMI; risk decreased as BMI increased to approximately 28 kg/m(2), and then it plateaued. Relative to obese patients, patients with a BMI of 18.5 kg/m(2) had a 27% increased risk of having a PFS event (95% CI, 20% to 34%) and a 50% increased risk of death (95% CI, 43% to 56%). Low BMI was associated with poorer survival for men than women (interaction P < .001). BMI was not predictive of treatment effect.

CONCLUSION

Low BMI is associated with an increased risk of progression and death among the patients enrolled on the mCRC trials, with no increased risk for elevated BMI, in contrast to the adjuvant setting. Possible explanations include negative effects related to cancer cachexia in patients with low BMI, increased drug delivery or selection bias in patients with high BMI, and potential for an interaction between BMI and molecular signaling pathways.

The prevalence and outcomes of frailty in older cancer patients: a systematic review

BACKGROUND

Frailty is a state of vulnerability to poor resolution of homeostasis following a stressor event, such as chemotherapy or cancer surgery. Better knowledge of the epidemiology of frailty could help drive a global cancer care strategy for older people. The aim of this review was to establish the prevalence and outcomes of frailty and pre-frailty in older cancer patients.

METHODS

Observational studies that reported data on the prevalence and/or outcomes of frailty in older cancer patients with any stage of solid or haematological malignancy were considered. We searched Medline, CINAHL, Cochrane Library, EMBASE, Web of Science, Allied and Complementary medicine, Psychinfo and ProQuest (1 January 1996 to 30 June 2013). The primary outcomes were prevalence of frailty, treatment-related side-effects, unplanned hospitalization and mortality. Risk of bias was assessed using the Newcastle-Ottawa checklist.

RESULTS

Data from 20 studies evaluating 2916 participants are included. The median reported prevalence of frailty and pre-frailty was 42% (range 6%-86%) and 43% (range 13%-79%), respectively. A median of 32% (range 11%-78%) of patients were classified as fit. Frailty was independently associated with increased all-cause mortality [adjusted 5-year hazard ratio (HR) 1.87, 95% confidence interval (CI) 1.36-2.57]. There was evidence of increased risk of postoperative mortality for both frailty (adjusted 30-day HR 2.67, 95% CI 1.08-6.62) and pre-frailty (adjusted HR 2.33, 95% CI 1.20-4.52). Treatment complications were more frequent in those with frailty, including intolerance to cancer treatment (adjusted odds ratio 4.86, 95% CI 2.19-10.78) and postoperative complications (adjusted 30-day HR 3.19, 95% CI 1.68-6.04).

CONCLUSIONS

More than half of older cancer patients have pre-frailty or frailty and these patients are at increased risk of chemotherapy intolerance, postoperative complications and mortality. The findings of this review support routine assessment of frailty in older cancer patients to guide treatment decisions, and the development of multidisciplinary geriatric oncology services.

Association of age with survival in patients with metastatic colorectal cancer: analysis from the ARCAD Clinical Trials Program

PURPOSE

This study addressed whether age is prognostic for overall survival (OS) or progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

A total of 20,023 patients from 24 first-line clinical trials in the ARCAD (Aide et Recherche en Cancérologie Digestive) database were analyzed. Primary age effects and interactions with age,sex, performance status (PS), and metastatic site were modeled using Cox proportional hazards stratified by treatment arm within study.

RESULTS

Of total patients, 3,051 (15%) were age < or =50 years. Age was prognostic for both OS (P < .001)and PFS (P < .001), with U-shaped risk (i.e., highest risk was evident in youngest and oldest patients). Relative to patients of middle age, the youngest patients experienced 19% (95% CI, 7% to 33%) increased risk of death and 22% (95% CI, 10% to 35%) increased risk of progression. The oldest patients experienced 42% (95% CI, 31% to 54%) increased risk of death and 15% (95% CI, 7% to 24%) increased risk of progression or death. This relationship was more pronounced in the first year of follow-up. Age remained marginally significant for OS (P = .08) when adjusted forPS, sex, and presence of liver, lung, or peritoneal metastases, and age was significant in an adjusted model for PFS (P = .005). The age effect did not differ by site of metastatic disease, year of enrollment, type of therapy received, or biomarker mutational status.

CONCLUSION

Younger and older age are associated with poorer OS and PFS among treated patients with mCRC. Younger and older patients may represent higher-risk populations, and additional studies are warranted.

Nomograms for overall survival (OS) and progression-free survival (PFS) in metastatic colorectal cancer (mCRC): Construction from 19,678 ARCAD patients

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Background: Prospective survival prediction of patients with metastatic colorectal cancer is difficult. Prognosis estimation based on readily available clinicopathologic factors has the potential to inform clinical practice and improve risk stratification for clinical trials. We constructed prognostic nomograms for OS and PFS in mCRC using the multi-trial ARCAD database. Methods: Data from 19,678 mCRC pts accrued to 24 first line randomized phase III clinical trials since 1997 were used to construct and validate Cox models for PFS and OS, stratified by treatment arm within each study. Candidate variables included age, gender, BMI, performance status, colon vs. rectal cancer, prior chemotherapy, number of metastatic sites, sites of metastases (liver, lung, lymph nodes), and baseline bilirubin, albumin, white blood cell count, hemoglobin, platelets, absolute neutrophil count, and derived neutrophil:lymphocyte ratio (dNLR). Missing data (<11%) were imputed, continuous variables modeled with splines, and clinically relevant pairwise interactions considered if p<0.001. Final models were internally validated via bootstrapping to obtain optimism-corrected calibration and discrimination C-indices, and externally validated using a 10% holdout sample from each trial. Results: Nomograms for OS and PFS including remaining variables were well calibrated with C-indices of 0.66 and 0.60, respectively. Evaluation of external validity revealed good concordance; 71% and 67% respectively between predicted (> vs. <50% probability) and actual (yes/no) 1-year OS and 6-month PFS, and median 1-year OS and 6-month PFS predictions fell within the actual 95% Kaplan-Meier intervals. Gender, liver and lung metastases, and dNLR were not prognostic for OS; prior chemo, colon vs. rectum, dNLR, liver and lymph node metastases, and gender did not predict for PFS. No clinically relevant pairwise interactions were identified. Conclusions: The proposed nomograms are well calibrated and internally and externally valid. These tools have the potential to aid prognostication and patient/physician communication, and balance risk in randomized trials in mCRC.

InterAACT: An international multicenter open label randomized phase II advanced anal cancer trial comparing cisplatin (CDDP) plus 5-fluorouracil (5-FU) versus carboplatin (CBDCA) plus weekly paclitaxel (PTX) in patients with inoperable locally recurrent (ILR) or metastatic disease

TPS792

Background: Metastatic squamous cell carcinoma of the anus (SCCA) is a rare condition with 5-year overall survival (OS) rate of 32%. CDDP/5-FU is commonly used in the first-line treatment of patients with ILR or metastatic disease. This practice is based on retrospective series and data from randomised trials are lacking. Recent retrospective studies showed promising activity of CBDCA/PTX in this setting. Methods: InterAACT is an international, multicentre, open label, randomised phase II trial comparing two chemotherapy regimens in patients with ILR or metastatic SCCA. Eligible patients are randomised in a 1:1 ratio to CDDP (60 mg/mq, D1q21) plus 5-FU (1000 mg/mq/24h, D1-4q21) or CBDCA (AUC 5, D1q28) plus PTX (80 mg/mq, D1,8,15q28). Stratification factors are: performance status, extent of disease, HIV status and country. The primary endpoint is response rate (RR). Secondary endpoints include progression-free survival, OS, toxicity and quality of life. Based on a RR estimate of 40% in the CDDP/5-FU arm 80 patients are to be recruited to detect 10% difference in RR between the two arms with 80% power (phase II selection trial design). Correlative biomarker analyses are planned in tumour tissue and blood samples. The trial is sponsored by The Royal Marsden NHS Foundation Trust and endorsed by the International Rare Cancer Initiative (IRCI) group. Approximately 50 centres in the UK, Europe (EORTC), Scandinavia, US (ECOG-ACRIN) and Australia (AGITG) are estimated to participate and recruitment is anticipated to be completed within 3 years. Recruitment started in December 2013. As of September 16, 2014, 6 sites in the UK are open to recruitment and 6 patients have been randomised (3 to CDDP/5-FU and 3 to CBDCA/PTX). InterAACT aims to provide the first randomised evidence for the treatment of ILR and metastatic SCCA, to identify the optimal chemotherapy backbone to combine with targeted agents in future studies and to confirm the feasibility of conducting an international multicentre trial for this rare tumour. Clinical trial information: NCT02051868.

Individual patient data analysis of progression-free survival versus overall survival as a first-line end point for metastatic colorectal cancer in modern randomized trials: findings from the analysis and research in cancers of the digestive system database

PURPOSE

Progression-free survival (PFS) has previously been established as a surrogate for overall survival (OS) for first-line metastatic colorectal cancer (mCRC). Because mCRC treatment has advanced in the last decade with extended OS, this surrogacy requires re-examination.

METHODS

Individual patient data from 16,762 patients were available from 22 first-line mCRC studies conducted from 1997 to 2006; 12 of those studies tested antiangiogenic and/or anti-epidermal growth factor receptor agents. The relationship between PFS (first event of progression or death) and OS was evaluated by using R(2) statistics (the closer the value is to 1, the stronger the correlation) from weighted least squares regression of trial-specific hazard ratios estimated by using Cox and Copula models.

RESULTS

Forty-four percent of patients received a regimen that included biologic agents. Median first-line PFS was 8.3 months, and median OS was 18.2 months. The correlation between PFS and OS was modest (R(2), 0.45 to 0.69). Analyses limited to trials that tested treatments with biologic agents, nonstrategy trials, or superiority trials did not improve surrogacy.

CONCLUSION

In modern mCRC trials, in which survival after the first progression exceeds time to first progression, a positive but modest correlation was observed between OS and PFS at both the patient and trial levels. This finding demonstrates the substantial variability in OS introduced by the number of lines of therapy and types of effective subsequent treatments and the associated challenge to the use of OS as an end point to assess the benefit attributable to a single line of therapy. PFS remains an appropriate primary end point for first-line mCRC trials to detect the direct treatment effect of new agents.

Mismatch repair status and BRAF mutation status in metastatic colorectal cancer patients: a pooled analysis of the CAIRO, CAIRO2, COIN, and FOCUS studies

PURPOSE

To determine the prevalence and prognostic value of mismatch repair (MMR) status and its relation to BRAF mutation (BRAF(MT)) status in metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

A pooled analysis of four phase III studies in first-line treatment of mCRC (CAIRO, CAIRO2, COIN, and FOCUS) was performed. Primary outcome parameter was the hazard ratio (HR) for median progression-free survival (PFS) and overall survival (OS) in relation to MMR and BRAF. For the pooled analysis, Cox regression analysis was performed on individual patient data.

RESULTS

The primary tumors of 3,063 patients were analyzed, of which 153 (5.0%) exhibited deficient MMR (dMMR) and 250 (8.2%) a BRAF(MT). BRAF(MT) was observed in 53 (34.6%) of patients with dMMR tumors compared with 197 (6.8%) of patients with proficient MMR (pMMR) tumors (P < 0.001). In the pooled dataset, median PFS and OS were significantly worse for patients with dMMR compared with pMMR tumors [HR, 1.33; 95% confidence interval (CI), 1.12-1.57 and HR, 1.35; 95% CI, 1.13-1.61, respectively), and for patients with BRAF(MT) compared with BRAF wild-type (BRAF(WT)) tumors (HR, 1.34; 95% CI, 1.17-1.54 and HR, 1.91; 95% CI, 1.66-2.19, respectively). PFS and OS were significantly decreased for patients with BRAF(MT) within the group of patients with pMMR, but not for BRAF status within dMMR, or MMR status within BRAF(WT) or BRAF(MT).

CONCLUSIONS

Prevalence of dMMR and BRAF(MT) in patients with mCRC is low and both biomarkers confer an inferior prognosis. Our data suggest that the poor prognosis of dMMR is driven by the BRAF(MT) status.

Mismatch repair status and BRAF mutation status in metastatic colorectal cancer patients: a pooled analysis of the CAIRO, CAIRO2, COIN, and FOCUS studies

PURPOSE

To determine the prevalence and prognostic value of mismatch repair (MMR) status and its relation to BRAF mutation (BRAF(MT)) status in metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

A pooled analysis of four phase III studies in first-line treatment of mCRC (CAIRO, CAIRO2, COIN, and FOCUS) was performed. Primary outcome parameter was the hazard ratio (HR) for median progression-free survival (PFS) and overall survival (OS) in relation to MMR and BRAF. For the pooled analysis, Cox regression analysis was performed on individual patient data.

RESULTS

The primary tumors of 3,063 patients were analyzed, of which 153 (5.0%) exhibited deficient MMR (dMMR) and 250 (8.2%) a BRAF(MT). BRAF(MT) was observed in 53 (34.6%) of patients with dMMR tumors compared with 197 (6.8%) of patients with proficient MMR (pMMR) tumors (P < 0.001). In the pooled dataset, median PFS and OS were significantly worse for patients with dMMR compared with pMMR tumors [HR, 1.33; 95% confidence interval (CI), 1.12-1.57 and HR, 1.35; 95% CI, 1.13-1.61, respectively), and for patients with BRAF(MT) compared with BRAF wild-type (BRAF(WT)) tumors (HR, 1.34; 95% CI, 1.17-1.54 and HR, 1.91; 95% CI, 1.66-2.19, respectively). PFS and OS were significantly decreased for patients with BRAF(MT) within the group of patients with pMMR, but not for BRAF status within dMMR, or MMR status within BRAF(WT) or BRAF(MT).

CONCLUSIONS

Prevalence of dMMR and BRAF(MT) in patients with mCRC is low and both biomarkers confer an inferior prognosis. Our data suggest that the poor prognosis of dMMR is driven by the BRAF(MT) status.

A feasibility study testing four hypotheses with phase II outcomes in advanced colorectal cancer (MRC FOCUS3): a model for randomised controlled trials in the era of personalised medicine?

BACKGROUND

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Molecular markers of chemotherapeutic response and toxicity in colorectal cancer

Outcomes in colorectal cancer have improved over the last 15 years; this is in part due to the optimization of 5-fluorouracil schedules and the introduction of new and effective chemotherapeutic agents, such as irinotecan and oxaliplatin. However, not all patients respond to these agents and a proportion may suffer severe side effects from particular chemotherapy drugs. These observations have resulted in a concerted research effort to identify markers of chemotherapy efficacy and toxicity. Here we review the evidence for using molecular markers to individualize chemotherapy treatment in colorectal cancer.

Panitumumab and irinotecan versus irinotecan alone for patients with KRAS wild-type, fluorouracil-resistant advanced colorectal cancer (PICCOLO): a prospectively stratified randomised trial

Background

Therapeutic antibodies targeting EGFR have activity in advanced colorectal cancer, but results from clinical trials are inconsistent and the population in which most benefit is derived is uncertain. Our aim was to assess the addition of panitumumab to irinotecan in pretreated advanced colorectal cancer.

Methods

In this open-label, randomised trial, we enrolled patients who had advanced colorectal cancer progressing after fluoropyrimidine treatment with or without oxaliplatin from 60 centres in the UK. From December, 2006 until June, 2008, molecularly unselected patients were recruited to a three-arm design including irinotecan (control), irinotecan plus ciclosporin, and irinotecan plus panitumumab (IrPan) groups. From June 10, 2008, in response to new data, the trial was amended to a prospectively stratified design, restricting panitumumab randomisation to patients with KRAS wild-type tumours; the results of the comparison between the irinotcan and IrPan groups are reported here. We used a computer-generated randomisation sequence (stratified by previous EGFR targeted therapy and then minimised by centre, WHO performance status, previous oxaliplatin, previous bevacizumab, previous dose modifications, and best previous response) to randomly allocate patients to either irinotecan or IrPan. Patients in both groups received 350 mg/m² intravenous irinotecan every 3 weeks (300 mg/m² if aged ≥70 years or a performance status of 2); patients in the IrPan group also received intravenous panitumumab 9 mg/kg every 3 weeks. The primary endpoint was overall survival in KRAS wild-type patients who had not received previous EGFR targeted therapy, analysed by intention to treat. Tumour DNA was pyrosequenced for KRAS_c.146, BRAF, NRAS, and PIK3CA mutations, and predefined molecular subgroups were analysed for interaction with the effect of panitumumab. This study is registered, number ISRCTN93248876.

Results

Between Dec 4, 2006, and Aug 31, 2010, 1198 patients were enrolled, of whom 460 were included in the primary population of patients with KRAS_c.12–13,61 wild-type tumours and no previous EGFR targeted therapy. 230 patients were randomly allocated to irinotecan and 230 to IrPan. There was no difference in overall survival between groups (HR 1·01, 95% CI 0·83–1·23; p=0·91), but individuals in the IrPan group had longer progression-free survival (0·78, 0·64–0·95; p=0·015) and a greater number of responses (79 [34%] patients vs 27 [12%]; p<0·0001) than did individuals in the irinotecan group. Grade 3 or worse diarrhoea (64 [29%] of 219 patients vs 39 [18%] of 218 patients), skin toxicity (41 [19%] vs none), lethargy (45 [21]% vs 24 [11%]), infection (42 [19%] vs 22 [10%]) and haematological toxicity (48 [22%] vs 27 [12%]) were reported more commonly in the IrPan group than in the irinotecan group. We recorded five treatment-related deaths, two in the IrPan group and three in the irinotecan group.

Interpretation

Adding panitumumab to irinotecan did not improve the overall survival of patients with wild-type KRAS tumours. Further refinement of molecular selection is needed for substantial benefits to be derived from EGFR targeting agents.

Funding

Cancer Research UK, Amgen Inc.