Optimal maintenance strategy following FOLFOX plus anti-EGFR induction therapy in patients with RAS wild type metastatic colorectal cancer: An individual patient data pooled analysis of randomised clinical trials

BACKGROUND

Anti-EGFR antibodies plus doublet chemotherapy is the standard of care in RAS/BRAF wild-type metastatic colorectal cancer (mCRC). No phase-3 level of evidence is available to guide treatment de-escalation after anti-EGFR-based first-line. Several randomised clinical trials investigated de-intensification strategies with 5-fluorouracil/leucovorin (5-FU/LV) and/or anti-EGFR.

METHODS

We performed an individual patient data pooled analysis of Valentino, Panama, MACRO-2, COIN-B trials including RAS wild-type mCRC patients who received first-line therapy with FOLFOX plus panitumumab or cetuximab followed by pre-specified maintenance strategy. Only patients who started maintenance according to the assigned arm were included. Patients were categorised by type of maintenance (i.e. 5-FU/LV, anti-EGFR or 5-FU/LV + anti-EGFR). Progression-free survival (PFS) and overall survival (OS) were calculated from the start of maintenance; toxicity was evaluated for the maintenance treatment period.

RESULTS

A total of 518 patients were included in the pooled analysis. Overall, 123, 185 and 210 patients received maintenance with 5-FU/LV, anti-EGFR, 5-FU/LV + anti-EGFR, respectively. Median PFS was 5.6, 6.0 and 9.0 (P = 0.009) and OS was 25.7, 24.0 and 28.0 months (P = 0.134) in 5-FU/LV, anti-EGFR and 5-FU/LV + anti-EGFR arms, respectively. Monotherapy maintenance (either 5-FU/LV or anti-EGFR) was inferior to combination in terms of PFS (hazard ratios [HR] 1.26, P = 0.016) and non-significantly trending also in OS (HR 1.20, P = 0.111). An increase of overall any grade and grade ≥ 3 AEs and selected AEs was reported in combination compared to either 5-FU/LV or anti-EGFR arms.

CONCLUSIONS

This pooled analysis including four randomised phase II supports the use of 5-FU/LV plus anti-EGFR as the preferred maintenance regimen. Data provide rational for a more individualised maintenance treatment approach based on tumour and patients features.

Adding new experimental arms to randomised clinical trials: Impact on error rates

BACKGROUND

Experimental treatments pass through various stages of development. If a treatment passes through early-phase experiments, the investigators may want to assess it in a late-phase randomised controlled trial. An efficient way to do this is adding it as a new research arm to an ongoing trial while the existing research arms continue, a so-called multi-arm platform trial. The familywise type I error rate is often a key quantity of interest in any multi-arm platform trial. We set out to clarify how it should be calculated when new arms are added to a trial some time after it has started.

METHODS

We show how the familywise type I error rate, any-pair and all-pairs powers can be calculated when a new arm is added to a platform trial. We extend the Dunnett probability and derive analytical formulae for the correlation between the test statistics of the existing pairwise comparison and that of the newly added arm. We also verify our analytical derivation via simulations.

RESULTS

Our results indicate that the familywise type I error rate depends on the shared control arm information (i.e. individuals in continuous and binary outcomes and primary outcome events in time-to-event outcomes) from the common control arm patients and the allocation ratio. The familywise type I error rate is driven more by the number of pairwise comparisons and the corresponding (pairwise) type I error rates than by the timing of the addition of the new arms. The familywise type I error rate can be estimated using Šidák's correction if the correlation between the test statistics of pairwise comparisons is less than 0.30.

CONCLUSIONS

The findings we present in this article can be used to design trials with pre-planned deferred arms or to add new pairwise comparisons within an ongoing platform trial where control of the pairwise error rate or familywise type I error rate (for a subset of pairwise comparisons) is required.

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.

Pharmacogenetic analyses of 2183 patients with advanced colorectal cancer; potential role for common dihydropyrimidine dehydrogenase variants in toxicity to chemotherapy

BACKGROUND

Inherited genetic variants may influence response to, and side-effects from, chemotherapy. We sought to generate a comprehensive inherited pharmacogenetic profile for oxaliplatin and 5FU/capecitabine therapy in advanced colorectal cancer (aCRC).

METHODS

We analysed more than 200 potentially functional, common, inherited variants in genes within the 5FU, capecitabine, oxaliplatin and DNA repair pathways, together with four rare dihydropyrimidine dehydrogenase (DPYD) variants, in 2183 aCRC patients treated with oxaliplatin-fluoropyrimidine chemotherapy with, or without, cetuximab (from MRC COIN and COIN-B trials). Primary end-points were response, any toxicity and peripheral neuropathy. We had >85% power to detect odds ratios (ORs) = 1.3 for variants with minor allele frequencies >20%.

RESULTS

Variants in DNA repair genes (Asn279Ser in EXO1 and Arg399Gln in XRCC1) were most associated with response (OR 1.9, 95% confidence interval [CI] 1.2-2.9, P = 0.004, and OR 0.7, 95% CI 0.5-0.9, P = 0.003, respectively). Common variants in DPYD (Cys29Arg and Val732Ile) were most associated with toxicity (OR 0.8, 95% CI 0.7-1.0, P = 0.008, and OR 1.6, 95% CI 1.1-2.1, P = 0.006, respectively). Two rare DPYD variants were associated with increased toxicity (Asp949Val with neutropenia, nausea and vomiting, diarrhoea and infection; IVS14+1G>A with lethargy, diarrhoea, stomatitis, hand-foot syndrome and infection; all ORs > 3). Asp317His in DCLRE1A was most associated with peripheral neuropathy (OR 1.3, 95% CI 1.1-1.6, P = 0.003). No common variant associations remained significant after Bonferroni correction.

CONCLUSIONS

DNA repair genes may play a significant role in the pharmacogenetics of aCRC. Our data suggest that both common and rare DPYD variants may be associated with toxicity to fluoropyrimidine-based chemotherapy.

Comprehensive pharmacogenetic profiling of the epidermal growth factor receptor pathway for biomarkers of response to, and toxicity from, cetuximab

BACKGROUND

Somatic mutations in the epidermal growth factor receptor (EGFR) intracellular signalling pathways predict non-response to cetuximab in the treatment of advanced colorectal cancer (aCRC). We hypothesised that common germline variants within these pathways may also play similar roles.

METHODS

We analysed 54 potentially functional, common, inherited EGFR pathway variants in 815 patients with aCRC treated with oxaliplatin-fluoropyrimidine chemotherapy plus cetuximab. Primary endpoints were response and skin rash (SR). We had >85% power to detect ORs=1.6 for variants with minor allele frequencies >20%.

RESULTS

We identified five potential biomarkers for response and four for SR, although none remained significant after correction for multiple testing. Our initial data supported a role for Ser313Pro in PIK3R2 in modulating response to cetuximab-in patients with KRAS wild-type CRCs, 36.4% with one allele encoding proline responded, as compared with 71.2% homozygous for allele encoding serine (OR 0.23, 95% CI 0.09 to 0.56, p=0.0014), and this association was predictive for cetuximab (pinteraction=0.017); however, independent replication failed to validate this association. No previously proposed predictive biomarkers were validated.

CONCLUSIONS

Our study highlights the need to validate potential pharmacogenetic biomarkers. We did not find strong evidence for common germline biomarkers of cetuximab response and toxicity.

Randomized controlled pilot trial of naloxone-on-release to prevent post-prison opioid overdose deaths

BACKGROUND AND AIMS

Naloxone is an opioid antagonist used for emergency resuscitation following opioid overdose. Prisoners with a history of heroin injection have a high risk of drug-related death soon after release from prison. The NALoxone InVEstigation (N-ALIVE) pilot trial (ISRCTN34044390) tested feasibility measures for randomized provision of naloxone-on-release (NOR) to eligible prisoners in England.

DESIGN

Parallel-group randomized controlled pilot trial.

SETTING

English prisons.

PARTICIPANTS

A total of 1685 adult heroin injectors, incarcerated for at least 7 days pre-randomization, release due within 3 months and more than 6 months since previous N-ALIVE release.

INTERVENTION

Using 1 : 1 minimization, prisoners were randomized to receive on release a pack containing either a single 'rescue' injection of naloxone or a control pack with no syringe.

MEASUREMENTS

Key feasibility outcomes were tested against prior expectations: on participation (14 English prisons; 2800 prisoners), consent (75% for randomization), returned prisoner self-questionnaires (RPSQs: 207), NOR-carriage (75% in first 4 weeks) and overdose presence (80%).

FINDINGS

Prisons (16) and prisoners (1685) were willing to participate [consent rate, 95% confidence interval (CI) = 70-74%]; 218 RPSQs were received; NOR-carriage (95% CI = 63-79%) and overdose presence (95% CI = 75-84%) were as expected. We randomized 842 to NOR and 843 to control during 30 months but stopped early, because only one-third of NOR administrations were to the ex-prisoner. Nine deaths within 12 weeks of release were registered for 1557 randomized participants released before 9 December 2014.

CONCLUSIONS

Large randomized trials are feasible with prison populations. Provision of take-home emergency naloxone prior to prison release may be a life-saving interim measure to prevent heroin overdose deaths among ex-prisoners and the wider population.

External data required timely response by the Trial Steering-Data Monitoring Committee for the NALoxone InVEstigation (N-ALIVE) pilot trial

The prison-based N-ALIVE pilot trial had undertaken to notify the Research Ethics Committee and participants if we had reason to believe that the N-ALIVE pilot trial would not proceed to the main trial. In this paper, we describe how external data for the third year of before/after evaluation from Scotland's National Naloxone Programme, a related public health policy, were anticipated by eliciting prior opinion about the Scottish results in the month prior to their release as official statistics. We summarise how deliberations by the N-ALIVE Trial Steering-Data Monitoring Committee (TS-DMC) on N-ALIVE's own interim data, together with those on naloxone-on-release (NOR) from Scotland, led to the decision to cease randomization in the N-ALIVE pilot trial and recommend to local Principal Investigators that NOR be offered to already-randomized prisoners who had not yet been released.

Patients' preferences for adjuvant sorafenib after resection of intermediate or high-risk renal cell carcinoma in the SORCE trial: What makes it worthwhile?

415

Background: SORCE is an international, double-blind, placebo-controlled, phase 3 trial comparing adjuvant sorafenib for 1 year, for 3 years, or observation after resection of intermediate or high risk (as per the Leibovich score), localised renal cell carcinoma (RCC). We determined the survival benefits that SORCE participants judged necessary to make adjuvant sorafenib worthwhile 3 months after starting study treatment. Methods: Participants recruited to SORCE from Australia and selected UK sites completed a validated, self-administered questionnaire 3 months after starting study treatment to determine the minimum survival benefits they judged necessary to make adjuvant sorafenib worthwhile. Scenarios used baseline survival times (without adjuvant sorafenib) of 5 and 15 years; and baseline survival rates (without adjuvant sorafenib) of 65% and 85% at 5 years. Preferences were determined for 1 year of adjuvant sorafenib (versus none) and for 3 years of adjuvant sorafenib (versus 1 year). All tests were 2-sided and non-parametric. This substudy of SORCE was conducted by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP). Results: The 179 participants were mostly male (72%) with a median age of 57 years (range 29 to 78). Participants allocated sorafenib judged larger benefits necessary to make 1 year of adjuvant sorafenib worthwhile than those allocated placebo: median benefit of an extra 1 year versus an extra 1 month for baselines of 5 years (p=0.004) and 15 years (p=0.02); median benefit of an extra 5% versus an extra 1% for baseline of 65% (p=0.03), and an extra 3% versus an extra 1% for a baseline of 85% (p=0.07). Larger survival benefits were judged necessary to make 3 years of adjuvant sorafenib worthwhile (versus 1 year) regardless of treatment allocation: median benefit of an extra 2 months to 1 year for baselines of 5 years (p=0.02) and 15 years (0.02). Conclusions: Experienced toxicity and duration of treatment are important determinants of patients’ preferences for adjuvant sorafenib in RCC.

Intermittent chemotherapy plus either intermittent or continuous cetuximab for first-line treatment of patients with KRAS wild-type advanced colorectal cancer (COIN-B): a randomised phase 2 trial

BACKGROUND

Advanced colorectal cancer is treated with a combination of cytotoxic drugs and targeted treatments. However, how best to minimise the time spent taking cytotoxic drugs and whether molecular selection can refine this further is unknown. The primary aim of this study was to establish how cetuximab might be safely and effectively added to intermittent chemotherapy.

METHODS

COIN-B was an open-label, multicentre, randomised, exploratory phase 2 trial done at 30 hospitals in the UK and one in Cyprus. We enrolled patients with advanced colorectal cancer who had received no previous chemotherapy for metastases. Randomisation was done centrally (by telephone) by the Medical Research Council Clinical Trials Unit using minimisation with a random element. Treatment allocation was not masked. Patients were assigned (1:1) to intermittent chemotherapy plus intermittent cetuximab or to intermittent chemotherapy plus continuous cetuximab. Chemotherapy was FOLFOX (folinic acid and oxaliplatin followed by bolus and infused fluorouracil). Patients in both groups received FOLFOX and weekly cetuximab for 12 weeks, then either had a planned interruption (those taking intermittent cetuximab) or planned maintenance by continuing on weekly cetuximab (continuous cetuximab). On RECIST progression, FOLFOX plus cetuximab or FOLFOX was recommenced for 12 weeks followed by further interruption or maintenance cetuximab, respectively. The primary outcome was failure-free survival at 10 months. The primary analysis population consisted of patients who completed 12 weeks of treatment without progression, death, or leaving the trial. We tested BRAF and NRAS status retrospectively. The trial was registered, ISRCTN38375681.

FINDINGS

We registered 401 patients, 226 of whom were enrolled. Results for 169 with KRAS wild-type are reported here, 78 (46%) assigned to intermittent cetuximab and 91 (54%) to continuous cetuximab. 64 patients assigned to intermittent cetuximab and 66 of those assigned to continuous cetuximab were included in the primary analysis. 10-month failure-free survival was 50% (lower bound of 95% CI 39) in the intermittent group versus 52% (lower bound of 95% CI 41) in the continuous group; median failure-free survival was 12.2 months (95% CI 8.8-15.6) and 14.3 months (10.7-20.4), respectively. The most common grade 3-4 adverse events were skin rash (21 [27%] of 77 patients vs 20 [22%] of 92 patients), neutropenia (22 [29%] vs 30 [33%]), diarrhoea (14 [18%] vs 23 [25%]), and lethargy (20 [26%] vs 19 [21%]).

INTERPRETATION

Cetuximab was safely incorporated in two first-line intermittent chemotherapy strategies. Maintenance of biological monotherapy, with less cytotoxic chemotherapy within the first 6 months, in molecularly selected patients is promising and should be validated in phase 3 trials.

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.

MRC SORCE trial: Analysis of patients' presenting characteristics, tumor staging, and surgical approach

496

Background: SORCE is a randomised double blind trial of sorafenib, given for one or three years, versus placebo for patients at moderate or high risk of disease recurrence after surgical excision of primary renal cell carcinoma (RCC). Methods: Between July 2007 and April 2013, 1,711 patients were recruited from the UK (78%), Australia, France, Belgium, Denmark, The Netherlands and Spain. We describe the presenting characteristics, staging and surgical details of the randomised population. The surgical approach was at the surgeon’s discretion. Results: Baseline information is available for 1,681 patients (98%). Median age was 59 years (range 19 to 86): 1,195 (71%) were male. Histology was conventional/clear cell in 86%. T category was pT1a (<1%), pT1b (11%), pT2 (23%), pT3a-4 (65%). 47% were at high risk of recurrence with Leibovich scores of ≥6. Surgical data are available for 1,528 patients (89%). Total (radical) nephrectomy was performed for 97% of patients with 44% having laparoscopic surgery, of which 60% had a transperitoneal approach and 10% required conversion to open surgery. Some form of lymph node dissection was performed in 25% of patients (33% of open procedures and 15% of lap. procedures). The ipsi-lateral adrenal was removed in 47% and 11% had simultaneous resection of other structures/organs. Excision of venous extension was required in 19%. Laparoscopic procedures were performed for 58% of patients with maximum tumour diameter (MTD) <10cm and 17% of those with MTD ≥ 10 cm. Intra-operative complications were reported in 6% and post-operative complications reported in 12%. Hospital stay was median (IQR) 4 days (3-5) for patients having laparoscopic procedures and 7 days (5-8) for open surgery. Hospital stay was median (IQR) 8 days (6-11) for those having post-operative complications compared to 5 days (4-7) for uncomplicated recovery. Conclusions: These data reveal the varied surgical approaches to excision of primary RCC and will inform future adjuvant trials. The use of lymph node dissection appears arbitrary and evidence of benefit from randomised controlled trials is required. Analysis of the effect of sorafenib on disease free survival is likely to be performed in 2016. Clinical trial information: ISRCTN38934710.

Comprehensive pharmacogenetic profiling of advanced colorectal cancer

3509

Background: Inherited genetic factors may influence a patient’s response to, and side effects from, chemotherapy and biological therapies. Here, we sought to generate a comprehensive inherited pharmacogenetic profile for advanced colorectal cancer (aCRC). Methods: We analysed 260 potentially functional coding region and promoter variants in genes within the 5-FU, capecitabine, oxaliplatin, EGFR and DNA repair pathways in 2183 patients with aCRC treated with oxaliplatin-fluoropyrimidine chemotherapy ± cetuximab (from the MRC COIN and COIN-B trials). Primary outcomes assessed were 12-week response, skin rash (SR) (for those receiving cetuximab), dose-reduction or delay in treatment due to any toxicity and peripheral neuropathy (PN). Results: For variants with minor allele frequencies >20%, we had >85% power to detect an effect on response / toxicity with an OR of 1.3. In patients treated with chemotherapy + cetuximab, 5 and 4 coding region variants in the EGFR pathway were associated with response and SR, respectively. The most significant associations were with variants in members of phosphatidylinositol 3-kinase regulatory subunit. In patients treated with chemotherapy ± cetuximab, 8 coding region variants in the 5-FU, capecitabine, oxaliplatin or DNA repair pathways were associated with response, 8 with any toxicity and 5 with PN. The most significant associations for response were with variants in DNA repair genes and, for any toxicity, with common variants in DPYD. Conclusions: Our study highlights the difficulty in identifying inherited biomarkers for the treatment of aCRC - despite using samples from the largest reported randomised trial for aCRC, with considerable power to detect alleles of small effects, none of the associations remained significant after rigorous correction for multiple testing.

Fatal case of sorafenib-associated idiosyncratic hepatotoxicity in the adjuvant treatment of a patient with renal cell carcinoma

Background

Sorafenib is an orally available kinase inhibitor with activity at Raf, PDGFβ and VEGF receptors that is licensed for the treatment of advanced renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). Current evidence-based post-nephrectomy management of individuals with localized RCC consists of surveillance-based follow up. The SORCE trial is designed to investigate whether treatment with adjuvant sorafenib can reduce recurrence rates in this cohort.

Case presentation

Here we report an idiosyncratic reaction to sorafenib resulting in fatal hepatotoxicity and associated renal failure in a 62 year-old man treated with sorafenib within the SORCE trial.

Conclusion

This is the first reported case of sorafenib exposure associated fatal toxicity in the adjuvant setting and highlights the unpredictable adverse effects of novel adjuvant therapies.

Use of epiregulin (EREG) and amphiregulin (AREG) gene expression to predict response to cetuximab (cet) in combination with oxaliplatin (Ox) and 5FU in the first-line treatment of advanced colorectal cancer (aCRC)

32

Background: Previous data suggests the EGF ligands EREG/AREG may predict outcome of KRAS wt patients (pts) treated with cet in the chemo-refractory setting but this finding has not been previously reported from first line randomised trials. Methods: FFPE samples from primary tumours of pts in Arms A&B of the COIN trial of Ox fluoropyrimidine (Fp) +/- cet were analysed for EGFR IHC, KRAS/NRAS/BRAF mutation and EREG/AREG expression by RT-PCR. Ligand levels were assessed against baseline data, prognostic markers as uni/multivariate analyses and as predictive markers in wild type (wt) and mutant (mt) cohorts and separately by Fp backbone [capecitabine (CapOx) or 5FU (FOLFOX)]. Tests for interaction were performed with EREG/AREG continuous, using Flexible Parametric survival analysis. Results: 952/1630 (57%) of pts were evaluable for all parameters. High EREG/AREG levels were associated with KRAS wt (p<0.005), BRAF wt, absence of MSI and with primary tumour in left colon/rectum, presence of liver metastases, post randomisation radical surgery, high CEA (p<0.05) and ALKP. In the control arm, high EREG/AREG conferred a better prognosis among KRAS wt pts in a multivariate analysis. High EREG predicted for OS benefit from cet. treatment in KRAS wt pts, (n=525, p=0.017) and, separately, in pts treated with FOLFOX (n=310, p=0.021), with greatest effect in the “combined” subgroup (KRAS wt + FOLFOX, n=176, p=0.0042). Conversely a trend towards disbenefit was observed in KRAS wt pts treated with XELOX (n=349, p=0.14). Conclusions: The data suggest a prognostic effect of EREG/AREG in aCRC. The original hypothesis, that KRAS wt patients with high EREG expression have improved outcome with cet, is limited to patients treated with FOLFOX in the first-line setting. This data further suggests that capecitabine in combination with oxaliplatin and cetuximab produces a sub-optimal outcome.

Oxaliplatin/capecitabine vs oxaliplatin/infusional 5-FU in advanced colorectal cancer: the MRC COIN trial

Background:

COIN compared first-line continuous chemotherapy with the same chemotherapy given intermittently or with cetuximab in advanced colorectal cancer (aCRC).

Methods:

Choice between oxaliplatin/capecitabine (OxCap) and oxaliplatin/leucovorin (LV)/infusional 5-FU (OxFU) was by physician and patient choice and switching regimen was allowed. We compared OxCap with OxFU and OxCap+cetuximab with OxFU+cetuximab retrospectively in patients and examined efficacy, toxicity profiles and the effect of mild renal impairment.

Results:

In total, 64% of 2397 patients received OxCap(±cetuximab). Overall survival, progression free survival and overall response rate were similar between OxCap and OxFU but rate of radical surgeries was higher for OxFU. Progression free survival was longer for OxFU+cetuximab compared with OxCap+cetuximab but other efficacy measures were similar. Oxaliplatin/LV/infusional 5-FU (±cetuximab) was associated with more mucositis and infection whereas OxCap(±cetuximab) caused more gastrointestinal toxicities and palmar-plantar erythema. In total, 118 patients switched regimen, mainly due to toxicity; only 16% came off their second regimen due to intolerance. Patients with creatinine clearance (CrCl) 50–80 ml min⁻¹ on OxCap(±cetuximab) or OxFU+cetuximab had more dose modifications than those with better renal function.

Conclusions:

Overall, OxFU and OxCap are equally effective in treating aCRC. However, the toxicity profiles differ and switching from one regimen to the other for poor tolerance is a reasonable option. Patients with CrCl 50–80 ml min⁻¹ on both regimens require close toxicity monitoring.

Epiregulin (EREG) and amphiregulin (AREG) gene expression to predict response to cetuximab therapy in combination with oxaliplatin (Ox) and 5FU in first-line treatment of advanced colorectal cancer (aCRC)

3516

Background: Previous data suggest the EGF ligands EREG/AREG may predict outcome of KRAS wt patients (pts) in the chemo-refractory setting but has not been previously reported from first line randomised trials. Methods: FFPE samples from primary tumors of pts in Arms A&B of the COIN trial of Ox fluoropyrimidine (Fp) +/- cet were analysed for EGFR IHC, KRAS/NRAS/BRAF mutation and EREG/AREG expression by RT-PCR. Ligand levels were assessed against baseline data, prognostic markers as uni/multivariate analyses and as predictive markers in wild type (wt) and mutant (mt) cohorts and separately by Fp backbone [capecitabine (CapOx) or 5FU (FOLFOX)]. Tests for interaction were performed with EREG/AREG continuous, using Flexible Parametric survival analysis. Optimal cutoffs for predictive effects were defined using point at which 95% CI first excluded zero. Results: 952/1630 (57%) of pts were evaluable for all parameters. EREG/AREG were highly correlated Pearson’s rho (ρ) = 0.74; p<0.0001. High EREG/AREG levels were associated with KRAS wt (p<0.005) and with primary tumor in left colon/rectum, presence of liver metastases and high CEA (p<0.05). In the control arm, high EREG/AREG conferred a better prognosis among KRAS wt pts in multivariate. EREG superseded AREG in a combined model. High EREG predicted for OS benefit in KRAS wt pts treated with FOLFOX +cet, with optimal cut-off 80th centile. OS HR for ±cet ≥80th centile =0.33, 95% CI 0.14-0.78, p=0.011; <80% centile HR=0.99, 95% CI 0.67-1.47, p=0.96; interaction p=0.059; ≥50th centile HR=0.66, 95% CI 0.40-1.09, p=0.11; <50% centile HR=1.09, 95% CI 0.66-1.81, p=0.73; interaction p=0.17. Similar results were seen for PFS, with optimal cut-off 50th centile. There was no predictive effect for pts treated with CapOx. Conclusions: The data suggest a prognostic effect of EREG/AREG in aCRC. The original hypothesis, that KRAS wt patients with high EREG expression have improved outcome with cet, seems to be limited to patients treated with FOLFOX in the first-line setting.

Intermittent chemotherapy (CT) plus continuous or intermittent cetuximab (C) in the first-line treatment of advanced colorectal cancer (aCRC): Results of the two-arm phase II randomized MRC COIN-B trial

536^

Background: COIN-B is a trial of intermittent chemotherapy (ICT) plus intermittent cetuximab (C) vs ICT plus continuous C in the first-line treatment of aCRC. It complements the COIN trial by investigating how C might safely and effectively be added to an ICT strategy.

Methods: Patients (pts) had measurable aCRC; no prior CT for metastases; WHO PS 0-2 and good organ function. Randomisation was: Arm D - continuous OxFU + weekly C for 12 wks then a planned break from all therapy; Arm E - OxFU + weekly C for 12 wks then weekly C. Upon RECIST progression on either arm, OxFU (or FU) plus C was restarted and continued until progression on maximal tolerated therapy. Prospective KRAS testing was introduced in May 2008. Primary outcome measure is Failure-Free Survival (FFS) at 10 months (mo) in KRAS-wt pts who had not progressed, died or failed the treatment strategy within 3 mo of randomisation. The trial was powered to differentiate between a desired 10-mo FFS rate of 50% and a minimum of 35%, in 136 pts (168 allowing for drop-outs). Secondary outcome measures included safety, overall survival (OS) and toxicity.

Results: 169 KRAS-wt pts were randomised 07/07 to 06/10, 77 arm D / 92 arm E. Median age 64 years (IQR 55-70); 92% PS 0-1. In Arms D and E respectively, 65 (84%) and 67 (73%) pts were eligible for the primary analysis; 10-mo FFS rates were 48% vs 54% (one-sided 95% confidence limit 37% and 43% respectively). Median FFS was 12.0 vs 13.7 mo respectively (IQR 6.1-20.3 and 8.6-23.2). Median OS was 20.1 vs 18.4 mo. First CFI length was 3.7 mo vs 5.1 mo (IQR 2.5-6.2 and 2.5-8.9). In pre-planned exploratory analysis, median time to progression/death after chemo break was 3.1 mo (IQR 2.1-8.1) in Arm D and 6.0 mo (IQR 2.9-10.9) in Arm E. Toxicity was similar and only 1 arm D pt had G 3 hypersensitivity following C reintroduction. Analyses by BRAF & NRAS (tested retrospectively) will be presented.

Conclusions: C was safely incorporated in 2 ICT strategies. Continuous C as maintenance was associated with a longer CFI and longer time to progression/death. This encouraging strategy of incorporating biological maintenance therapy needs validation in phase III trials.

FOCUS 3: A study to determine the feasibility of molecular selection of therapy using K-RAS, B-RAF, and topo-1 in patients with advanced colorectal cancer (ACRC)

563

Background: Molecular characteristics of cancer vary between individuals. In future increasing numbers of trials will require assessment of biomarkers in order to allocate patients into enriched populations in which targeted therapies are more likely to be effective. The FOCUS 3 trial is a feasibility study to assess whether tumour samples could be collected from referring hospitals’ pathology departments, sent to designated reference laboratories for biomarker evaluation, and results provided to oncologists within 10 working days.

Methods: Patients with ACRC, fit for chemotherapy, were registered from 24 centres between 02.10 and 04.11. Following consent, paraffin embedded tumour samples were sent to Cardiff or Leeds for analysis of topoisomerase 1 (topo-1) by immunohistochemistry and of KRAS and BRAF mutation status, and results were forwarded to the MRC CTU. Patients were classified into 1 of 4 molecular strata, which determined the set of 2 hypothesis driven experimental therapies they could be randomised to in addition to control chemotherapy (irinotecan + 5FU). At this stage eligibility was reconfirmed and consent for randomisation obtained.

Results: 332 patients were registered to participate in FOCUS 3. Biomarker results were provided to oncologists within 10 working days (wd) in 71%, within 15 wd in 91% and within 20 wd in 99% patients. A 4 stage suite of patient information sheets (PIS) was designed and implemented to avoid patient overload; separate information sheets were provided to patients at stages during the consent process and patient understanding was assessed. 93% of eligible patients gave consent to randomisation. KRAS mutation was detected in 88 (36%), BRAF in 15 (6%), 2 patients had both mutations and 133 were double wildtype. 77% of patients were high (2-3), 19% low (0-1) and 4% inconclusive for topo-1. Tumour response and toxicity results for the 244 randomised patients will be presented.

Conclusions: Patient samples can be collected and analysed at designated reference laboratories within acceptable timeframes. Multi-arm designs can be made acceptable to patients through good PIS, ensured by patient and carer input into their design.

Does anti-EGFR therapy improve outcome in advanced colorectal cancer? A systematic review and meta-analysis

BACKGROUND

Randomised controlled trials (RCTs) of anti-EGFR monoclonal antibodies (MAb) in patients with advanced colorectal cancer (aCRC) have reported conflicting results.

METHODS

A systematic review of RCTs comparing standard treatments±anti-EGFR MAbs was conducted. Hazard ratios (HR) for progression-free (PFS) and overall survival (OS) were derived for patients with wild-type (WT) and mutant KRAS. Prespecified analyses were conducted for line of treatment, MAb used, chemotherapy regimen, and choice of fluouropyrimidine. Trials using bevacizumab on both arms were included in a sensitivity analysis.

RESULTS

Fourteen eligible RCTs were identified, with results by KRAS status available for ten RCTs. For third line treatment, the effect of anti-EGFR MAbs depended on KRAS status (interaction p<0.00001), with a PFS benefit for patients with WT KRAS only (HR=0.43, 95% CI 0.35-0.52, p<0.00001). For first and second line treatment, the effect also appeared to depend on KRAS status (interaction p=0.0003), again with the PFS benefit only for patients with WT KRAS (HR=0.83, 95% CI 0.76-0.90, p<0.0001). Differences between trial results (heterogeneity p=0.02, I(2)=62%) were best explained by the fluouropyrimidine used, with PFS benefits confined to trials combining MAbs alongside 5FU-based chemotherapy (HR=0.77, 95% CI 0.70-0.85, p<0.00001). There was no evidence of a PFS benefit when MAbs were given with bevacizumab.

CONCLUSIONS

For aCRC patients with WT KRAS, there are clear benefits of anti-EGFR MAbs in the third line and in the first and second line, when used alongside infusional 5FU-based regimens. However, there is no benefit for patients with KRAS mutations.

Intermittent versus continuous oxaliplatin and fluoropyrimidine combination chemotherapy for first-line treatment of advanced colorectal cancer: results of the randomised phase 3 MRC COIN trial

BACKGROUND

When cure is impossible, cancer treatment should focus on both length and quality of life. Maximisation of time without toxic effects could be one effective strategy to achieve both of these goals. The COIN trial assessed preplanned treatment holidays in advanced colorectal cancer to achieve this aim.

METHODS

COIN was a randomised controlled trial in patients with previously untreated advanced colorectal cancer. Patients received either continuous oxaliplatin and fluoropyrimidine combination (arm A), continuous chemotherapy plus cetuximab (arm B), or intermittent (arm C) chemotherapy. In arms A and B, treatment continued until development of progressive disease, cumulative toxic effects, or the patient chose to stop. In arm C, patients who had not progressed at their 12-week scan started a chemotherapy-free interval until evidence of disease progression, when the same treatment was restarted. Randomisation was done centrally (via telephone) by the MRC Clinical Trials Unit using minimisation. Treatment allocation was not masked. The comparison of arms A and B is described in a companion paper. Here, we compare arms A and C, with the primary objective of establishing whether overall survival on intermittent therapy was non-inferior to that on continuous therapy, with a predefined non-inferiority boundary of 1.162. Intention-to-treat (ITT) and per-protocol analyses were done. This trial is registered, ISRCTN27286448.

FINDINGS

1630 patients were randomly assigned to treatment groups (815 to continuous and 815 to intermittent therapy). Median survival in the ITT population (n=815 in both groups) was 15.8 months (IQR 9.4-26.1) in arm A and 14.4 months (8.0-24.7) in arm C (hazard ratio [HR] 1.084, 80% CI 1.008-1.165). In the per-protocol population (arm A, n=467; arm C, n=511), median survival was 19.6 months (13.0-28.1) in arm A and 18.0 months (12.1-29.3) in arm C (HR 1.087, 0.986-1.198). The upper limits of CIs for HRs in both analyses were greater than the predefined non-inferiority boundary. Preplanned subgroup analyses in the per-protocol population showed that a raised baseline platelet count, defined as 400,000 per μL or higher (271 [28%] of 978 patients), was associated with poor survival with intermittent chemotherapy: the HR for comparison of arm C and arm A in patients with a normal platelet count was 0.96 (95% CI 0.80-1.15, p=0.66), versus 1.54 (1.17-2.03, p=0.0018) in patients with a raised platelet count (p=0.0027 for interaction). In the per-protocol population, more patients on continuous than on intermittent treatment had grade 3 or worse haematological toxic effects (72 [15%] vs 60 [12%]), whereas nausea and vomiting were more common on intermittent treatment (11 [2%] vs 43 [8%]). Grade 3 or worse peripheral neuropathy (126 [27%] vs 25 [5%]) and hand-foot syndrome (21 [4%] vs 15 [3%]) were more frequent on continuous than on intermittent treatment.

INTERPRETATION

Although this trial did not show non-inferiority of intermittent compared with continuous chemotherapy for advanced colorectal cancer in terms of overall survival, chemotherapy-free intervals remain a treatment option for some patients with advanced colorectal cancer, offering reduced time on chemotherapy, reduced cumulative toxic effects, and improved quality of life. Subgroup analyses suggest that patients with normal baseline platelet counts could gain the benefits of intermittent chemotherapy without detriment in survival, whereas those with raised baseline platelet counts have impaired survival and quality of life with intermittent chemotherapy and should not receive a treatment break.

FUNDING

Cancer Research UK.

Addition of cetuximab to oxaliplatin-based first-line combination chemotherapy for treatment of advanced colorectal cancer: results of the randomised phase 3 MRC COIN trial

BACKGROUND

In the Medical Research Council (MRC) COIN trial, the epidermal growth factor receptor (EGFR)-targeted antibody cetuximab was added to standard chemotherapy in first-line treatment of advanced colorectal cancer with the aim of assessing effect on overall survival.

METHODS

In this randomised controlled trial, patients who were fit for but had not received previous chemotherapy for advanced colorectal cancer were randomly assigned to oxaliplatin and fluoropyrimidine chemotherapy (arm A), the same combination plus cetuximab (arm B), or intermittent chemotherapy (arm C). The choice of fluoropyrimidine therapy (capecitabine or infused fluouroracil plus leucovorin) was decided before randomisation. Randomisation was done centrally (via telephone) by the MRC Clinical Trials Unit using minimisation. Treatment allocation was not masked. The comparison of arms A and C is described in a companion paper. Here, we present the comparison of arm A and B, for which the primary outcome was overall survival in patients with KRAS wild-type tumours. Analysis was by intention to treat. Further analyses with respect to NRAS, BRAF, and EGFR status were done. The trial is registered, ISRCTN27286448.

FINDINGS

1630 patients were randomly assigned to treatment groups (815 to standard therapy and 815 to addition of cetuximab). Tumour samples from 1316 (81%) patients were used for somatic molecular analyses; 565 (43%) had KRAS mutations. In patients with KRAS wild-type tumours (arm A, n=367; arm B, n=362), overall survival did not differ between treatment groups (median survival 17·9 months [IQR 10·3-29·2] in the control group vs 17·0 months [9·4-30·1] in the cetuximab group; HR 1·04, 95% CI 0·87-1·23, p=0·67). Similarly, there was no effect on progression-free survival (8·6 months [IQR 5·0-12·5] in the control group vs 8·6 months [5·1-13·8] in the cetuximab group; HR 0·96, 0·82-1·12, p=0·60). Overall response rate increased from 57% (n=209) with chemotherapy alone to 64% (n=232) with addition of cetuximab (p=0·049). Grade 3 and higher skin and gastrointestinal toxic effects were increased with cetuximab (14 vs 114 and 67 vs 97 patients in the control group vs the cetuximab group with KRAS wild-type tumours, respectively). Overall survival differs by somatic mutation status irrespective of treatment received: BRAF mutant, 8·8 months (IQR 4·5-27·4); KRAS mutant, 14·4 months (8·5-24·0); all wild-type, 20·1 months (11·5-31·7).

INTERPRETATION

This trial has not confirmed a benefit of addition of cetuximab to oxaliplatin-based chemotherapy in first-line treatment of patients with advanced colorectal cancer. Cetuximab increases response rate, with no evidence of benefit in progression-free or overall survival in KRAS wild-type patients or even in patients selected by additional mutational analysis of their tumours. The use of cetuximab in combination with oxaliplatin and capecitabine in first-line chemotherapy in patients with widespread metastases cannot be recommended.

FUNDING

Cancer Research UK, Cancer Research Wales, UK Medical Research Council, Merck KGgA.

KRAS and BRAF mutations in advanced colorectal cancer are associated with poor prognosis but do not preclude benefit from oxaliplatin or irinotecan: results from the MRC FOCUS trial

PURPOSE

Activating mutation of the KRAS oncogene is an established predictive biomarker for resistance to anti-epidermal growth factor receptor (anti-EGFR) therapies in advanced colorectal cancer (aCRC). We wanted to determine whether KRAS and/or BRAF mutation is also a predictive biomarker for other aCRC therapies.

PATIENTS AND METHODS

The Medical Research Council Fluorouracil, Oxaliplatin and Irinotecan: Use and Sequencing (MRC FOCUS) trial compared treatment sequences including first-line fluorouracil (FU), FU/irinotecan or FU/oxaliplatin in aCRC. Tumor blocks were obtained from 711 consenting patients. DNA was extracted and KRAS codons 12, 13, and 61 and BRAF codon 600 were assessed by pyrosequencing. Mutation (mut) status was assessed first as a prognostic factor and then as a predictive biomarker for the benefit of adding irinotecan or oxaliplatin to FU. The association of BRAF-mut with loss of MLH1 was assessed by immunohistochemistry.

RESULTS

Three hundred eight (43.3%) of 711 patients had KRAS-mut and 56 (7.9%) of 711 had BRAF-mut. Mutation of KRAS, BRAF, or both was present in 360 (50.6%) of 711 patients. Mutation in either KRAS or BRAF was a poor prognostic factor for overall survival (OS; hazard ratio [HR], 1.40; 95% CI, 1.20 to 1.65; P < .0001) but had minimal impact on progression-free survival (PFS; HR, 1.16; 95% CI, 1.00 to 1.36; P = .05). Mutation status did not affect the impact of irinotecan or oxaliplatin on PFS or OS. BRAF-mut was weakly associated with loss of MLH1 staining (P = .012).

CONCLUSION

KRAS/BRAF mutation is associated with poor prognosis but is not a predictive biomarker for irinotecan or oxaliplatin. There is no evidence that patients with KRAS/BRAF mutated tumors are less likely to benefit from these standard chemotherapy agents.

Association of molecular markers with toxicity outcomes in a randomized trial of chemotherapy for advanced colorectal cancer: the FOCUS trial

PURPOSE

Predicting efficacy and toxicity could potentially allow individualization of cancer therapy. We investigated putative pharmacogenetic markers of chemotherapy toxicity in a large randomized trial.

PATIENTS, MATERIALS, AND METHODS

Patients were randomly assigned to different sequences of chemotherapy for advanced colorectal cancer. First-line therapy was fluorouracil (FU), irinotecan/FU (IrFU) or oxaliplatin/FU (OxFU). Patients allocated first-line FU had planned second-line irinotecan alone, IrFU, or OxFU. The primary toxicity outcome measure was toxicity-induced delay or dose reduction; the secondary outcome was Common Terminology Criteria of Adverse Events grade >or= 3 toxicity. DNA was analyzed in 1,188 patients; 1,036 were assessable for the primary outcome, including 688 treated with FU, 270 with IrFU (first or second line), 280 with OxFU (first or second line), 184 with irinotecan alone, and 454 with any irinotecan-containing regimen. Ten polymorphisms were assessed: thymidylate synthase-enhancer region (TYMS-ER), thymidylate synthase 1494 (TYMS-1494), dihydropyrimidine dehydrogenase (DPYD), methylenetetrahydrofolate reductase (MTHFR), mutL homolog 1 (MLH1), UDP glucuronyltransferase (UGT1A1), ATP-binding cassette group B gene 1 (ABCB1), x-ray cross-complementing group 1 (XRCC1), glutathione-S-transferase P1 (GSTP1), and excision repair cross-complementing gene 2 (ERCC2). Results Using the primary outcome measure, no polymorphism was significantly associated (P < .01) with the toxicity of any regimen or with the difference in toxicity of IrFU or OxFU versus FU alone. Trends (of doubtful significance) were seen for associations of XRCC1, ERCC2, and GSTP1 with toxicity during irinotecan regimens: XRCC1, primary end point, any irinotecan-containing regimen (P = .045); ERCC2, secondary end point, irinotecan alone (P = .003); GSTP1, secondary end point; IrFU (P = .039); and irinotecan alone (P = .05). There was no evidence of association of UGT1A1*28 with irinotecan toxicity.

CONCLUSION

These results do not support the routine clinical use of the evaluated polymorphisms, including UGT1A1*28. Further investigation of XRCC1, ERCC2, and GSTP1 as potential predictors of irinotecan toxicity is warranted.

Toxicity associated with combination oxaliplatin plus fluoropyrimidine with or without cetuximab in the MRC COIN trial experience

We present the preliminary toxicity data from the MRC COIN trial, a phase III randomised controlled trial of first-line therapy in advanced colorectal cancer, with particular reference to the addition of cetuximab to an oxaliplatin-fluoropyrimidine combination. A total of 804 patients were randomised between March 2005 and July 2006 from 78 centres throughout the United Kingdom. Patients were allocated to oxaliplatin plus fluoropyrimidine chemotherapy with or without the addition of weekly cetuximab. The choice of fluoropyrimidine (either 5-fluorouracil (5FU) or capecitabine) was decided by the treating physician and patient before randomisation. Toxicity data were collected from all patients. Two hundred and three patients received 5FU plus oxaliplatin (OxMdG, 25%), 333 oxaliplatin+capecitabine (Xelox, 41%), 102 received OxMdG+cetuximab (OxMdG+C, 13%) and 166 Xelox+cetuximab (21%). Percent grade 3/4 toxicities included diarrhoea 6, 15, 13 and 25%, nausea/vomiting 3, 7, 7 and 14% for OxMdG, Xelox, OxMdG+C and Xelox+C, respectively. Sixty-day all-cause mortality was 6, 5, 5 and 7%. Statistically significant differences were evident for patients receiving Xelox+cetuximab vs Xelox alone: diarrhoea relative risk (RR) 1.69 (1.17, 2.43, P=0.005) and nausea/vomiting RR 2.01 (1.16, 3.47, P=0.012). The excess toxicity observed in the oxaliplatin-, capecitabine-, cetuximab-treated patients led the trial management group to conclude that a capecitabine dose adjustment was required to maintain safety levels when using this regimen.

Predictive biomarkers of chemotherapy efficacy in colorectal cancer: results from the UK MRC FOCUS trial

PURPOSE

Candidate predictive biomarkers for irinotecan and oxaliplatin were assessed in 1,628 patients in Fluorouracil, Oxaliplatin, CPT-11: Use and Sequencing (FOCUS), a large randomized trial of fluorouracil alone compared with fluorouracil and irinotecan and compared with fluorouracil and oxaliplatin in advanced colorectal cancer.

METHODS

The candidate biomarkers were: tumor immunohistochemistry for MLH1/MSH2, p53, topoisomerase-1 (Topo1), excision repair cross-complementing gene 1 (ERCC1), O-6-methylguanine-DNA-methyltranserase (MGMT), and cyclooxygenase 2 (COX2); germline DNA polymorphisms in GSTP1, ABCB1, XRCC1, ERCC2, and UGT1A1. These were screened in more than 750 patients for interaction with benefit from irinotecan or oxaliplatin; two markers (Topo1 and MLH1/MSH2) met criteria to be taken forward for analysis in the full population. Primary end points were progression-free survival (PFS) and overall survival.

RESULTS

One thousand three hundred thirteen patients (81%) were assessable for Topo1 immunohistochemistry (low, < 10%; moderate, 10% to 50%; or high, > 50% tumor nuclei). In patients with low Topo1, PFS was not improved by the addition of either irinotecan (hazard ratio [HR], 0.98; 95% CI, 0.78 to 1.22) or oxaliplatin (HR, 0.85; 95% CI, 0.68 to 1.07); conversely, patients with moderate/high Topo1 benefited from the addition of either drug (HR, 0.48 to 0.70 in all categories; interaction P = .005; overall, P = .001 for irinotecan; P = .05 for oxaliplatin). High Topo1 was associated with a major overall survival benefit with first-line combination chemotherapy (HR, 0.60; median benefit, 5.3 months); patients with moderate or low Topo1 did not benefit (HR, 0.92 and 1.09, respectively; interaction P = .005). MLH1/MSH2 did not show significant interaction with treatment, although the low rate of loss (4.4%) limits the power of the study for this biomarker.

CONCLUSION

Topo1 immunohistochemistry identified subpopulations that did or did not benefit from irinotecan, and possibly also from oxaliplatin. If verified independently, this information will contribute to the individualization of treatment for colorectal cancer.

Different strategies of sequential and combination chemotherapy for patients with poor prognosis advanced colorectal cancer (MRC FOCUS): a randomised controlled trial

BACKGROUND

In the non-curative setting, the sequence in which anticancer agents are used, singly or in combination, may be important if patients are to receive the maximum period of disease control with the minimum of adverse effects. We compared sequential and combination chemotherapy strategies in patients with unpretreated advanced or metastatic colorectal cancer, who were regarded as not potentially curable irrespective of response.

METHODS

We studied patients with advanced colorectal cancer, starting treatment with non-curative intent. 2135 unpretreated patients were randomly assigned to three treatment strategies in the ratio 1:1:1. Strategy A (control group) was single-agent fluorouracil (given with levofolinate over 48 h every 2 weeks) until failure, then single-agent irinotecan. Strategy B was fluorouracil until failure, then combination chemotherapy. Strategy C was combination chemotherapy from the outset. Within strategies B and C, patients were randomly assigned to receive, as the combination regimen, fluorouracil plus irinotecan (groups B-ir and C-ir) or fluorouracil plus oxaliplatin (groups B-ox and C-ox). The primary endpoint was overall survival, analysed by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN 79877428.

RESULTS

Median survival of patients allocated to control strategy A was 13.9 months. Median survival of each of the other groups was longer (B-ir 15.0, B-ox 15.2, C-ir 16.7, and C-ox 15.4 months). However, log-rank comparison of each group against control showed that only C-ir--the first-line combination strategy including irinotecan--satisfied the statistical test for superiority (p=0.01). Overall comparison of strategy B with strategy C was within the predetermined non-inferiority boundary of HR=1.18 or less (HR=1.06, 90% CI 0.97-1.17).

INTERPRETATION

Our data challenge the assumption that, in this non-curative setting, maximum tolerable treatment must necessarily be used first-line. The staged approach of initial single-agent treatment upgraded to combination when required is not worse than first-line combination, and is an alternative option for discussion with patients.