Dataset Information

Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study.

ABSTRACT:

Background

RAS (KRAS and NRAS) testing is required to predict anti-epidermal growth factor receptor (EGFR) treatment efficacy in metastatic colorectal cancer (CRC). Although direct sequencing (DS) with manual microdissection (MMD) is widely used, a diagnostic kit providing rapid detections of RAS mutations would be clinically beneficial. We evaluated the MEBGEN(TM) RASKET KIT (RASKET KIT), a multiplex assay using PCR-reverse sequence specific oligonucleotide and xMAP(®) technology to concurrently detect exon 2, 3, and 4 RAS mutations in a short turnaround time (4.5 h/96-specimens).

Methods

Formalin-fixed paraffin-embedded (FFPE) tissues were obtained from 308 consenting patients with histologically-confirmed CRC at six hospitals in Japan. For the RASKET KIT, we used only 50-100 ng DNA from each FFPE specimen not processed by MMD. The primary endpoint was the concordance rate between RAS mutations identified with the RASKET KIT and two reference assays (DS with MMD and TheraScreen(®) K-RAS Mutation Kit). As the secondary endpoints, we evaluated the concordance rate between DS and the RASKET KIT for RAS mutations in the wild-type KRAS exon 2 population and the genotyping performance of the RASKET KIT compared with DS.

Findings

Among 307 analyzable specimens, the reference assays detected 140 (45.6%, 140/307) RAS mutations: 111 KRAS exon 2 and 29 other (minor) RAS mutations. The RASKET KIT detected 143 (46.6%, 143/307) mutations: 114 KRAS exon 2 and 29 minor RAS mutations. The between-method concordance rate was 96.7% (297/307) (95% CI: 94.1-98.4%). Minor RAS mutations were detected in 15.7% (30/191) of the wild-type KRAS exon 2 population (n = 191); the concordance rate was 98.4% (188/191) (95% CI: 95.5-99.7%). The concordance rate of RAS genotyping was 100% (139/139) (95% CI: 97-100%).

Interpretation

The RASKET KIT provides rapid and precise detections of RAS mutations and consequently, quicker and more effective anti-EGFR therapy for CRC (Study ID: UMIN000011784).

Funding

Medical & Biological Laboratories Co., Ltd. (MBL). MBL had roles in study design, data collection, data analysis, and writing of the report for the study.

SUBMITTER: Yoshino T

PROVIDER: S-EPMC4486202 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Publications

Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study.

Yoshino Takayuki T Muro Kei K Yamaguchi Kensei K Nishina Tomohiro T Denda Tadamichi T Kudo Toshihiro T Okamoto Wataru W Taniguchi Hiroya H Akagi Kiwamu K Kajiwara Takeshi T Hironaka Shuichi S Satoh Taroh T

EBioMedicine 20150214 4

<h4>Background</h4>RAS (KRAS and NRAS) testing is required to predict anti-epidermal growth factor receptor (EGFR) treatment efficacy in metastatic colorectal cancer (CRC). Although direct sequencing (DS) with manual microdissection (MMD) is widely used, a diagnostic kit providing rapid detections of RAS mutations would be clinically beneficial. We evaluated the MEBGEN(TM) RASKET KIT (RASKET KIT), a multiplex assay using PCR-reverse sequence specific oligonucleotide and xMAP(®) technology to con ...[more]

PMID: 26137573

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Project description:BackgroundThe OPUS study demonstrated that addition of cetuximab to 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX4) significantly improved objective response and progression-free survival (PFS) in the first-line treatment of patients with KRAS exon 2 wild-type metastatic colorectal cancer (mCRC). In patients with KRAS exon 2 mutations, a detrimental effect was seen upon addition of cetuximab to FOLFOX4. The current study reports outcomes in subgroups defined by extended RAS testing.Patients and methodsSamples from OPUS study KRAS exon 2 wild-type tumours were reanalysed for other RAS mutations in four additional KRAS codons (exons 3-4) and six NRAS codons (exons 2-4) using BEAMing. A cutoff of ⩾5% mutant/wild-type sequences was selected to define RAS status; we also report an analysis using a cutoff based on the technical lower limit for mutation identification (0.1%).ResultsOther RAS mutations were detected in 31/118 (26%) evaluable patients. In the extended analysis of RAS wild-type tumours (n=87), objective response was significantly improved by addition of cetuximab to FOLFOX4 (58% versus 29%; odds ratio 3.33 [95% confidence interval 1.36-8.17]; P=0.0084); although limited by population size, there also appeared to be trends favouring the cetuximab arm in terms of PFS and overall survival in the RAS wild-type group compared with the RAS evaluable group. There was no evidence that patients with other RAS mutations benefited from cetuximab, but small numbers precluded precise estimations of treatment effects. In the combined population of patients with any RAS mutation (KRAS exon 2 or other RAS), a clear detrimental effect was associated with addition of cetuximab to FOLFOX4.ConclusionPatients with RAS-mutant mCRC, as defined by mutations in KRAS and NRAS exons 2-4, derive no benefit and may be harmed by the addition of cetuximab to FOLFOX4. Restricting cetuximab administration to patients with RAS wild-type tumours will further tailor therapy to maximise benefit.

Dataset Information

Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study.

Background

Methods

Findings

Interpretation

Funding

Publications

Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study.

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