Article

Bokemeyer C, Bondarenko I, Hartmann JT, et al. Efficacy according to biomarker status of cetuximab plus FOLFOX-4 as first-line treatment for metastatic colorectal cancer: the OPUS study

Department of Oncology, Hematology, BMT with Section Pneumology, University Hospital, Hamburg-Eppendorf, Germany.
Annals of Oncology (Impact Factor: 7.04). 06/2011; 22(7):1535-46. DOI: 10.1093/annonc/mdq632
Source: PubMed

ABSTRACT

The randomized phase II OPUS (Oxaliplatin and Cetuximab in First-Line Treatment of Metastatic Colorectal Cancer) study showed that tumor KRAS mutation status was predictive for outcome in patients receiving cetuximab plus FOLFOX-4 (oxaliplatin/5-fluorouracil/folinic acid) as first-line therapy for metastatic colorectal cancer (mCRC).
The biomarker analysis was extended through the use of additional DNA samples extracted from stained tissue sections. KRAS and BRAF tumor mutation status was determined for new (and for BRAF, existing) samples using a PCR technique. Clinical outcome was reassessed according to mutation status. Overall survival data are presented.
Of 315 KRAS evaluable patient samples (93%), 179 tumors (57%) were KRAS wild type. Eleven of 309 (4%) KRAS/BRAF evaluable tumors (all KRAS wild type) carried BRAF mutations. The addition of cetuximab to FOLFOX-4 significantly improved progression-free survival (hazard ratio 0.567, P = 0.0064) and response (odds ratio 2.551, P = 0.0027) in patients with KRAS wild-type tumors. A favorable effect on survival was also observed.
These results confirm the efficacy of cetuximab plus FOLFOX-4 in the first-line treatment of patients with KRAS wild-type mCRC and confirm KRAS mutation status as an effective predictive biomarker. The small number of tumors with BRAF mutations precluded the drawing of definitive conclusions concerning the predictive or prognostic utility of this biomarker.

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    • "With targeted agents there was hope that better patient selection would follow and this has been the case for anti-EGFR therapy, but it remains elusive for therapy targeting VEGF. The KRAS gene exon 2 mutation is predictive of nonresponse to EGFR-targeted monoclonal antibody (MAb) therapy across all treatment lines, either as a single agent or in combination with irinotecan-or oxaliplatin-based chemotherapy (Amado et al, 2008; Karapetis et al, 2008; Bokemeyer et al, 2011; Van Cutsem et al, 2011). More recent evidence assessing the impact of additional RAS mutations (KRAS exons 3 and 4 and NRAS exons 1–4) has further defined the group of patients who do not respond to anti-EGFR agent. "
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    ABSTRACT: Background: Mutations affecting RAS genes are now established predictive markers of nonresponse to anti-EGFR antibodies in advanced CRC. This analysis assessed the prognostic and predictive impact of extended RAS and PIK3CA gene mutation status in patients receiving capecitabine plus or minus bevacizumab (±mitomycin C) in the randomised phase III MAX study. Methods: DNA was extracted from archival macrodissected formalin-fixed paraffin-embedded tumour tissue. Mutation status was determined using pyrosequencing, confirmed with Sanger sequencing (for equivocal RAS) and correlated with efficacy outcomes. Predictive analyses were undertaken using a test for interaction involving both C vs CB+CBM. Results: Of the available 280 of the 471 (59.4%) patients, mutations in KRAS exons 2, 3 and 4 and NRAS 2, 3 and 4 were as follows: 32%, 2.9%, 2.2%, 1.4%, 0.7% and 0% (total RAS MT 39%). The PIK3CA MT rate was 7.5% exon 9 and 3.6% exon 20. Extended RAS gene mutation status (WT vs MT) had no prognostic impact for PFS (HR 0.91 (0.71-1.17)) or OS (HR 0.95 (0.71-1.25)). The RAS gene mutation status was not predictive of the effectiveness of bevacizumab for PFS (HR 0.56 (0.37-0.85) for RAS MT and HR 0.69 (0.5-0.97) for RAS WT; P for interaction 0.50). The PIK3CA mutation was neither predictive for bevacizumab effect nor prognostic. Conclusion: Of KRAS exon 2 WT patients, 10% had additional RAS mutations. Neither all RAS gene mutation status nor PIK3CA mutation status was prognostic for PFS or OS, or predictive of bevacizumab outcome in patients with advanced CRC.
    No preview · Article · Mar 2015 · British Journal of Cancer
    • "There were no severe adverse events related to the study medications occurred in our patients. The toxicity profile was in line with the reported incidence in those large scale studies: CRYSTAL,[10] OPUS[9] and COIN[12] study, reflecting that this biweekly regimen is safe when used in combination with chemotherapy. "
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    ABSTRACT: Background: The efficacy and safety of using combination chemotherapy with cetuximab as first-line treatment in patients with K-ras wild-type colorectal cancers has been well established. In general, weekly cetuximab was given with biweekly chemotherapy FOLFOX-4 or FOLFIRI, synchronizing them would be appealed to both patients and health care professionals. Materials and Methods: This Phase II, prospective study investigated the efficacy and safety of using biweekly cetuximab 500 mg/m2 with chemotherapy FOLFOX-4 or FOLFIRI as first-line treatment for Chinese patients with K-ras wild-type metastatic colorectal cancer. The study endpoints included overall objective response (OR), progression-free survival (PFS), overall survival (OS) and safety. Results: Total 15 Chinese patients (male: 10 [67%]; median age: 60 [range 41-80]) were enrolled. Patients received median 12 cycles (range 2-12) of chemotherapy + cetuximab (FOLFOX-4 + cetuximab: 9 [60%]; FOLFIRI + cetuximab: 6 [40%]). Six patients (40%) with non-progressive disease after 12 cycles of chemotherapy + cetuximab carried on maintenance cetuximab. Median duration of follow-up (FU) was 23.7 months. The OR was 40% (complete response: 0%; partial response: 40%) for a disease control rate of 87%. Median PFS and OS were 7.8 months and 17.9 months respectively. For maintenance cetuximab phase, median PFS since the start of maintenance cetuximab was 6.8 months and median OS was 17.0 months. The only grade 3-4 toxicities were neutropenia (26.7%) in chemotherapy phase and acneiform rashes (16.7%) in maintenance phase. Conclusions: Biweekly cetuximab with combination chemotherapy was effective and safe as weekly dose. Further studies are warranted for the role of maintenance cetuximab.
    No preview · Article · Jul 2014 · South Asian Journal of Cancer
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    • "Specifically, BRAF is responsible for resistance when patients received anti-EGFR therapy in a second or subsequent round of treatment, as shown in several retrospective studies [10, 25, 27, 28]. In contrast, the predictive value of BRAF mutations in first line treatment has not been fully demonstrated [18, 29, 30]. A recent study conducted by Saridaki et al. showed lower PFS and OS in BRAF V600E mutated patients compared with wild-type (4.2 "
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    ABSTRACT: Targeting epidermal growth factor receptor (EGFR) has been one of the most effective colorectal cancer strategies. Anti-EGFR antibodies function by binding to the extracellular domain of EGFR, preventing its activation, and ultimately providing clinical benefit. KRAS mutations in codons 12 and 13 are recognized prognostic and predictive biomarkers that should be analyzed at the clinic prior to the administration of anti-EGFR therapy. However, still an important fraction of KRAS wild-type patients do not respond to the treatment. The identification of additional genetic determinants of primary or secondary resistance to EGFR targeted therapy for further improving the selection of patients is urgent. Herein, we review the latest published literature highlighting the most important genes that may predict resistance to anti-EGFR monoclonal antibodies in colorectal cancer patients. According to the available findings, the evaluation of BRAF, NRAS, PIK3CA, and PTEN status could be the right strategy to select patients who are likely to respond to anti-EGFR therapies. In the future, the combination of those biomarkers will help establish consensus that can be introduced into clinical practice.
    Full-text · Article · Jun 2014 · BioMed Research International
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