The TheraScreen: K-RAS kit detects seven mutations in codons 12 and 13 of the K-RAS oncogene. This kit has been CE-marked for professional diagnostic use.

Background
Mutations in the K-RAS oncogene are frequently found in human cancers. They are common in colorectal cancer, pancreatic cancer, lung adenocarcinoma, gall bladder cancer, bile duct cancer and thyroid cancer. These mutations can indicate prognosis and may be predictive of drug response. In particular, recent publications have shown that the successful treatment of metastatic Colorectal Cancer (mCRC), using monoclonal antibody therapies such as Panitumumab (Amgen) or Cetuximab (Erbitux, Merck), is directly linked to the oncogenic activation of the KRAS signalling pathway. (1-6).

Recently the European Commission has granted a conditional marketing authorization for Vectibix® (panitumumab) as monotherapy for the treatment of patients with non-mutated (wild-type) KRAS genes after failure of standard chemotherapy regimens. In September 2007 Vectibix received a positive opinion from CHMP (European Committee for Medicinal Products for Human Use) based upon the clinical data supporting the utility of K-RAS mutation status as a biomarker for a patient population that has few treatment options available to them. Amgen presented this pivotal data from the “408” study (7) at ECCO 14 (European Cancer Organisation) European Conference in Barcelona in September 2007, which used the TheraScreen: K-RAS Mutation Kit. The study concludes that the efficacy of panitumumab monotherapy in metastatic colorectal cancer seems confined to patients with non-mutated K-RAS.

For further information about Amgen’s Vectibix therapy and the relationship with a patients K-RAS mutation status, please visit the following sites:
www.amgen.com
www.vectibix.com
www.emea.europa.eu/pdfs/human/opinion/40511307en.pdf

The TheraScreen KRAS Kit is highly selective and robust, detecting the 7 key mutations in the K-RAS gene. DxS assays employ a real-time PCR format combining Scorpions® and ARMS® (allele specific PCR) technologies. These assays can detect 1% of mutant in a background of wild type genomic DNA. .

Intended Use
To aid doctors to identify colorectal cancer patients more likely to benefit from anti-EGFR therapies such as panitumumab.
The TheraScreen: K-RAS Kit is not intended for use to screen for or diagnose cancer.  Its use is intended as an adjunct to other prognostic factors currently used to select suitable patients for treatment with anti-EGFR therapies, based on the patient’s mutation status. The patient’s mutation status will be considered by a Clinician, alongside other disease factors to make a therapy decision. No treatment decision for cancer patients should be based on K-RAS mutation status alone.

Technological Principles
DxS has combined ARMS® (allele specific PCR) with the Scorpions® real-time PCR technology to develop sensitive and robust tests for tumour-borne K-RAS mutations.

K-RAS Mutations
The DxS kit detects the following mutations in codons 12 and 13 against a background of wild type genomic DNA in a real time PCR assay:

1. Gly12Asp (GGT>GAT)
2. Gly12Ala (GGT>GCT)
3. Gly12Val (GGT>GTT)
4. Gly12Ser (GGT>AGT)
5. Gly12Arg (GGT>CGT)
6. Gly12Cys (GGT>TGT)
7. Gly13Asp (GGC>GAC)

Protocol
After DNA extraction, real time PCR assays are performed to detect the target molecule.  By comparing control and mutant sample reactions users can detect and estimate low levels of mutation. No further sample processing is necessary and the time to result is <3 hours.

Kit Attributes:

• Maximises patient selection of most likely responders to anti EGFR therapies by accurate identification and exclusion of mutation positive patients, frequently missed by other methods
• Depending on the total amount of DNA present, the kit can detect 1% of mutant in a background of wild type genomic DNA. These sensitivity and detection levels are superior to commonly used methods such as sequencing.
• Simple and easy to follow protocol, with same day results.
• Sample types include DNA from plasma or fresh, frozen or paraffin embedded tissue (PET).
• Kit combines two technologies, ARMS® (allele specific PCR) and Scorpions® to detect mutations in real-time PCR reactions.
• Qualitative assessment of patient mutation status; accurately detects the 7 somatic mutations.
• The kit has been CE-marked and validated for use on the ABI 7500 real-time PCR machine. Other instruments may require additional validation.
  

Regulatory Registrations
DxS’ TheraScreen: K-RAS kit has been CE-marked for professional diagnostic use under the EU registration and the product is CE-marked under the European IVD Directive 98/79/EC. The product is registered in the following countries:

• United Kingdom                                            
• Germany                                                         
• Austria                                                            
• France                                                             
• Spain                                                              
• Italy                                                                
• Sweden                                                          
• Finland                                                           
• Norway                                                          
• Ireland                                                            
• Denmark                                                         
• Switzerland                                                    
• Poland                                                            
• Greece                                                            
• Netherlands                                                    
• Slovenia                                                          
• Czech Republic                                              
• Slovakia                                                          
• Belgium                                                          
• Hungary                                                         
• Lithuania                                                        
• Latvia    

Instructions For Use
To download the TheraScreen: K-RAS Instructions For Use protocol booklet, please register your details in the fields below and then you will be able to select the preferred language for the Instructions For Use.

How to Order
Please quote the product code and kit size when you order:
Product Code: KR-21 20 reaction kit
Product Code: KR-22 80 reaction kit

To place an order please email sales@dxsdiagnostics.com or call +44 161 606 7201

Technical Support / Frequently Asked Questions:
Click here for Knowledge Base & FAQ's Registration

References:

• E. Massarelli, M. Varella-Garcia, X. Tang, A. C. Xavier et al. (2007). KRAS Mutation Is an Important Predictor of Resistance to Therapy with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer. Clin Cancer Res 2007; 13 (10).
  
  
• William Pao, Theresa Y. Wang, Gregory J. Riely, Vincent A. Miller, Qiulu Pan, Marc Ladanyi et al. (2005). KRAS mutations and Primary Resistance of Lung Adenocarcinomas to Gefitinib or Erlotinib.  PloS Medicine 2(1): 57-61.
  
  
• D. A. Eberhard, B. E. Johnson, L.C. Amler, A. D. Goddard et al (2005). Mutations in the EGFR and in K-RAS are predictive and prognostic indicators in patients with NSCLC treated with chemotherapy alone and in combination with erlotinib. J Clin Oncol 23: 5900-5909.
  
  
• L. Toschi & F. Cappuzzo. (2007) Understanding the new genetics of responsiveness to EGFR tyrosine kinase inhibitors. Oncologist 12; 211-220.
  
  
• Sae-Won Han, Tae-You Kim, Yoon Kyung Jeon, Pil Gyu Hwang et al. (2006). Optimization of Patient Selection for Gefitinib in Non-Small Cell Lung Cancer by combined analysis of Epidermal Growth Factor Receptor Mutation, K-RAS Mutation, and AKT Phosphorylation.  Clin Cancer Res 12(8):2538-2544.
  
  
• Newton CR, Graham A, Heptinstall LE, Powell SJ, Summers C et al. (1989). Analysis of any point mutation in DNA. The amplification refractory mutation system (ARMS) Nucleic Acids Res. 17 (7): 2503-16.
  
  
• R.G. Amado et al. (2007) Analysis of K-RAS mutations in patients with metastatic colorectal cancer receiving panitumumab monotherapy. Presented at ECCO 2007.