August 2017 Abstracts

Cetuximab in treatment of metastatic colorectal cancer: final survival analyses and extended RAS data from the NORDIC-VII study.

Guren TK, Thomsen M, Kure EH, Sorbye H, Glimelius B, Pfeiffer P, Österlund P, Sigurdsson F, Lothe IMB, Dalsgaard AM, Skovlund E, Christoffersen T, Tveit KM.
Br J Cancer. 2017 May 9;116(10):1271-1278. doi: 10.1038/bjc.2017.93. Epub 2017 Apr 11.

Background:

The NORDIC-VII study is a randomised phase III trial of cetuximab plus continuous or intermittent fluorouracil, folinic acid, and oxaliplatin (Nordic FLOX) vs FLOX alone in first-line treatment of metastatic colorectal cancer. The present report presents an updated and final survival analysis with BRAF and extended RAS mutational status, 5 years after the primary analysis.

Methods:

A total of 566 patients were included in the intention-to-treat (ITT) population of the NORDIC-VII study. Updated survival status was obtained from 176 patients who were alive in the primary survival analyses. Samples from 223 tumours previously found to be KRAS (exon 2) and BRAF (V600E) wild-type, were re-analysed for KRAS (exons 3 and 4) and NRAS (exons 2-4) mutations.

Results:

Including the extended RAS analyses, RAS and BRAF mutational status was available from 457 patients (81% of the ITT population). RAS was mutated in 46% and BRAF in 12% of the tumours. RAS and BRAF, if mutated, were negative prognostic factors. The updated analyses confirmed the finding of the primary report that cetuximab did not provide any additional benefit when added to FLOX in patients with RAS/BRAF wild-type tumours, neither on progression-free nor overall survival. However, the outcomes in a subset of patients, which, after the first eight treatment cycles, received cetuximab alone, suggested a beneficial effect of cetuximab monotherapy.

Conclusion:

Adding cetuximab to Nordic FLOX did not provide any clinical benefit, but the data suggested an effect of cetuximab monotherapy in patients with RAS/BRAF wild-type tumours in the NORDIC-VII cohort. The data were compatible with a negative interaction between cetuximab and the Nordic FLOX chemotherapy backbone.

The difference in association between aspirin use and other thrombocyte aggregation inhibitors and survival in patients with colorectal cancer.

Frouws MA, Rademaker E, Bastiaannet E, van Herk-Sukel MPP, Lemmens VE, Van de Velde CJH, Portielje JEA, Liefers GJ.
Eur J Cancer. 2017 May;77:24-30. doi: 10.1016/j.ejca.2017.02.025. Epub 2017 Mar 26.

Background:

Several studies have suggested that the association between aspirin and improved cancer survival is mediated through the mechanism of aspirin as thrombocyte aggregation inhibitors (TAI). The aim of this study was to provide epidemiological evidence for this mechanism assessing the association between overall survival and the use of aspirin and non-aspirin TAI in patients with colorectal cancer.

Methods:

In this observational study, data from the Netherlands Comprehensive Cancer Organisation were linked to PHARMO Database Network. Patients using aspirin or aspirin in combination with non-aspirin TAI (dual users) were selected and compared with non-users. The association between overall survival and the use of (non-)aspirin TAI was analysed using Cox regression models with the use of (non-)aspirin TAI as a time-varying covariate.

Results:

In total, 9196 patients were identified with colorectal cancer and 1766 patients used TAI after diagnosis. Non-aspirin TAI were mostly clopidogrel and dipyridamole. Aspirin use was associated with a significant increased overall survival and hazard ratio (HR) 0.41 (95% confidence interval [CI] 0.37-0.47), and the use of non-aspirin TAI was not associated with survival of HR 0.92 (95% CI 0.70-1.22). Dual users did not have an improved overall survival when compared with patients using solely aspirin.

Conclusions:

Aspirin use after diagnosis of colorectal cancer was associated with significantly lower mortality rates and this effect remained significant after adjusting for potential confounders. No additional survival benefit was observed in patients using both aspirin and another TAI.

FOLFOXIRI Plus Bevacizumab as Conversion Therapy for Patients With Initially Unresectable Metastatic Colorectal Cancer: A Systematic Review and Pooled Analysis.

Tomasello G, Petrelli F, Ghidini M1, Russo A, Passalacqua R1, Barni S.
JAMA Oncol. 2017 Jul 13;3(7):e170278. doi: 10.1001/jamaoncol.2017.0278. Epub 2017 Jul 13.

Importance:

The combination of fluorouracil, oxaliplatin, and irinotecan plus bevacizumab (FOLFOXIRI-Bev) is an established and effective first-line chemotherapy regimen for metastatic colorectal cancer. However, resection rates of metastases and overall survival with this schedule have never been systematically evaluated in published studies including, but not limited to, the TRIBE (TRIplet plus BEvacizumab) trial.

Objectives:

To assess the clinical efficacy of FOLFOXIRI-Bev, including outcomes and rates of surgical conversions.

Data Sources:

A systematic review was conducted in October 2016 in concordance with the PRISMA guidelines of PubMed, the Cochrane Central Register of Controlled Trials, SCOPUS, Web of Science, Google Scholar, CINAHL, Ovid, and EMBASE using the terms FOLFOXIRI and bevacizumab and (colorectal cancer).

Study Selection:

Clinical trials, retrospective case series, and prospective case series that used FOLFOXIRI-Bev for the treatment of initially unresectable metastatic colorectal cancer in humans were included. Individual case reports and retrospective case series with fewer than 10 patients were excluded.

Data Extraction and Synthesis

Data were extracted independently by 2 reviewers on a predesigned, standardized form. Ultimately, data were aggregated to obtain the pooled effect size of efficacy, according to the random-effects model and weighted for the number of patients included in each trial.

Main Outcomes and Measures:

Median overall survival and progression-free survival, overall response rates, and rates of R0 surgical conversions and overall surgical conversions.

Results:

Eleven FOLFOXIRI-Bev studies published between 2010 and 2016 met the inclusion criteria and were pooled for analysis. The studies included 889 patients, with 877 patients clinically evaluable for overall response rates. The objective response rate to FOLFOXIRI-Bev was 69% (95% CI, 65%-72%; I2 = 25%). The rate of overall surgical conversions was 39.1% (95% CI, 26.9%-52.8%), and the rate of R0 surgical conversions was 28.1% (95% CI, 18.1%-40.8%). Median pooled overall survival was 30.2 months (95% CI, 26.5-33.7 months) in 6 trials with data available, and progression-free survival was 12.4 months (95% CI, 10.0-14.3 months) in 9 trials with data available. In meta-regression analysis, variables significantly associated with conversion surgery were disease limited to the liver and a higher median number of cycles (close to 12).

Conclusions and Relevance:

For patients with surgically unresectable metastatic colorectal cancer, FOLFOXIRI-Bev is associated with a significant overall response rate. Such an effective regimen leads to a probability of surgical conversion of distant metastases approaching 40%, with more than one-fourth of patients having an R0 resection.

Trastuzumab emtansine versus taxane use for previously treated HER2-positive locally advanced or metastatic gastric or gastro-oesophageal junction adenocarcinoma (GATSBY): an international randomised, open-label, adaptive, phase 2/3 study.

Lancet Oncol. 2017 May;18(5):640-653. doi: 10.1016/S1470-2045(17)30111-0. Epub 2017 Mar 23.
Thuss-Patience PC, Shah MA, Ohtsu A, Van Cutsem E, Ajani JA, Castro H, Mansoor W, Chung HC, Bodoky G, Shitara K, Phillips GDL, van der Horst T, Harle-Yge ML, Althaus BL, Kang YK.

Background:

Although trastuzumab plus chemotherapy is the standard of care for first-line treatment of HER2-positive advanced gastric cancer, there is no established therapy in the second-line setting. In GATSBY, we examined the efficacy and tolerability of trastuzumab emtansine in patients previously treated for HER2-positive advanced gastric cancer (unresectable, locally advanced, or metastatic gastric cancer, including adenocarcinoma of the gastro-oesophageal junction).

Methods:

This is the final analysis from GATSBY, a randomised, open-label, adaptive, phase 2/3 study, done at 107 centres (28 countries worldwide). Eligible patients had HER2-positive advanced gastric cancer and progressed during or after first-line therapy. In stage one of the trial, patients were randomly assigned to treatment groups (2:2:1) to receive intravenous trastuzumab emtansine (3·6 mg/kg every 3 weeks or 2·4 mg/kg weekly) or physician’s choice of a taxane (intravenous docetaxel 75 mg/m2 every 3 weeks or intravenous paclitaxel 80 mg/m2 weekly). In stage two, patients were randomly assigned to treatment groups (2:1) to receive the independent data monitoring committee (IDMC)-selected dose of trastuzumab emtansine (2·4 mg/kg weekly) or a taxane (same regimen as above). We used permuted block randomisation, stratified by world region, previous HER2-targeted therapy, and previous gastrectomy. The primary endpoint (overall survival) was assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01641939.

Findings:

Between Sept 3, 2012, and Oct 14, 2013, 70 patients were assigned to receive trastuzumab emtansine 3·6 mg/kg every 3 weeks, 75 to receive trastuzumab emtansine 2·4 mg/kg weekly, and 37 to receive a taxane in the stage 1 part of the trial. At the pre-planned interim analysis (Oct 14, 2013), the IDMC selected trastuzumab emtansine 2·4 mg/kg weekly as the dose to proceed to stage 2. By Feb 9, 2015, a further 153 patients had been randomly assigned to receive trastuzumab emtansine 2·4 mg/kg weekly and a further 80 to receive a taxane. At data cutoff, median follow-up was 17·5 months (IQR 12·1-23·0) for the trastuzumab emtansine 2·4 mg/kg weekly group and 15·4 months (9·2-18·1) in the taxane group. Median overall survival was 7·9 months (95% CI 6·7-9·5) with trastuzumab emtansine 2·4 mg/kg weekly and 8·6 months (7·1-11·2) with taxane treatment (hazard ratio 1·15, 95% CI 0·87-1·51, one-sided p=0·86). The trastuzumab emtansine 2·4 mg/kg group had lower incidences of grade 3 or more adverse events (134 [60%] of 224 patients treated with trastuzumab emtansine vs 78 [70%] of 111 patients treated with a taxane), and similar incidences of adverse events leading to death (eight [4%] vs four [4%]), serious adverse events (65 [29%] vs 31 [28%]), and adverse events leading to treatment discontinuation (31 [14%] vs 15 [14%]) than did taxane treatment. The most common grade 3 or more adverse events in the trastuzumab emtansine 2·4 mg/kg weekly group were anaemia (59 [26%]) and thrombocytopenia (25 [11%]) compared with neutropenia (43 [39%]), and anaemia (20 [18%]), in the taxane group. The most common serious adverse events were anaemia (eight [4%]), upper gastrointestinal haemorrhage (eight [4%]), pneumonia (seven [3%]), gastric haemorrhage (six [3%]), and gastrointestinal haemorrhage (five [2%]) in the trastuzumab emtansine 2·4 mg/kg weekly group compared with pneumonia (four [4%]), febrile neutropenia (four [4%]), anaemia (three [3%]), and neutropenia (three [3%]) in the taxane group.

Interpretation:

Trastuzumab emtansine was not superior to taxane in patients with previously treated, HER2-positive advanced gastric cancer. There is still an unmet need in this patient group and therapeutic options remain limited.