Genotyping Technology Effective for Hepatitis B,C

liver411

Wednesday December 19, 3:50 pm Eastern Time

Press Release



SOURCE: Visible Genetics Inc.

Visible Genetics' Trugene Genotyping Technology Effective for Hepatitis B and C



TORONTO, Dec. 19 /PRNewswire/ -- Visible Genetics Inc. (VGI, Nasdaq: VGIN) today presented results of comparative studies using its TRUGENE(TM) Hepatitis B virus (HBV) and Hepatitis C virus (HCV) genotyping tests at the international HEP-DART meeting in Hawaii. The results of one study demonstrated that the TRUGENE HBV Genotyping Kit reveals substantially more about the virus than other tests in common use. The second study confirmed that the TRUGENE HCV 5'NC Genotyping Kit is an accurate and reliable method for determining HCV genotype - a significant predictor of response to interferon therapy.



Visible Genetics' TRUGENE(TM) genotyping tests are performed using the Company's OpenGene(TM) DNA Sequencing System, which was recently cleared for market by the U.S. Food and Drug Administration as part of VGI's TRUGENE HIV-1 Genotyping Test. These results confirm that the sequencing equipment, now in use for HIV resistance testing in hundreds of laboratories the world over, can also be used for Hepatitis B and C.



"Hepatitis is a major global health issue. There are many drugs in development to treat hepatitis but already we are seeing the development of drug resistance for Hepatitis B. These latest results are encouraging in that they indicate that the TRUGENE technology, developed by Visible Genetics for the monitoring of resistance to HIV, has successfully been adapted for hepatitis B and C,'' stated Dr. Dean Winslow, VP Regulatory and Clinical Affairs for Visible Genetics.



This latest HBV study compared the TRUGENE HBV Genotyping Kit with the INNO-LiPA HBV DR test in an analysis of 18 plasma samples from patients with HBV infection. The TRUGENE system detected mutations in the polymerase gene -- the gene that most directly affects susceptibility to the drugs used to treat HBV -- in 14 of the 18 samples. In contrast the INNO-LiPA test only detected mutations in two of the samples.



HCV takes many forms that can be classified into six main genotypes and more than 90 subtypes. The genotype of the virus can dictate whether is will respond to interferon therapy. The HCV study compared the TRUGENE HCV 5'NC Genotyping Kit, which is commercially available as a research tool, with sequencing of the NS5b region of the viral genetic code (using the company's developmental TRUGENE HCV NS5b kit) -- currently considered to be the gold standard for identifying the many HCV subtypes. Fifty HCV-positive samples were analyzed and the results demonstrated 100% concordance for identifying the genotype of the viruses - confirming that the TRUGENE HCV 5'NC kit is an accurate and reliable method of rapidly determining the HCV genotype, information that can be used as the basis for treatment decision-making.



"The data from these latest studies add to the substantial evidence that the TRUGENE system is effective for viral genotyping in the clinical setting,'' said Richard T. Daly, President and CEO, Visible Genetics Inc. "Since the recent FDA market clearance of TRUGENE HIV-1, we are encouraged that these studies confirm the system is useful for HBV and HCV analysis patients as well.''



HBV Genotyping



The TRUGENE HBV Genotyping Test is rapid, single assay sequencing developed by VGI and currently available for research use. It analyzes the nucleic acid sequence of the genes encoding the surface antigen to determine the genotype of the virus and simultaneously detects mutations in the polymerase gene that may confer drug resistance. The genotyping information resulting from the test is used to assist in the selection of treatment regimens for individual patients.



The World Health Organization estimates that there are 400 million chronic HBV carriers worldwide, with approximately 1.25 million chronically infected persons in the U.S. Left untreated HBV can lead to cirrhosis, liver failure, and eventually hepatocellular carcinoma. In fact, approximately 20 percent of individuals with chronic HBV infection will develop cirrhosis. Historically, HBV genotyping has been performed using serological methods and because of advances in sequencing technology, genotypic analysis has become routine and current therapy may consist of antivirals and/or immune modulators. The TRUGENE HBV Genotyping Test combines the rapid method of CLIP(TM) sequencing with the GeneLibrarian HBV software module for simplified HBV sequence analysis.



The HBV test is based on the surface antigen sequence (from codon 100 to codon 200). The Gene Librarian(TM) HBV module contains reference sequences for genotypes A to F while surface antigen mutations in this region can also be detected. The TRUGENE HBV Genotyping Test sequences the pol gene region where most mutations occur.



HCV Genotyping



HCV genotyping is often used as a predictor of long term sustained response to drug therapy, more specifically to determine the duration of combination therapy (alfa-interferon-2b+ribavirin). Several methods for HCV genotyping have been developed and rely mainly on the amplification of viral sequences by the polymerase chain reaction (PCR) followed by detection via DNA sequencing. One of the most frequently used genomic regions for HCV genotyping is the 5'NC, as is used by the TRUGENE test.



Hepatitis C is the most common blood-borne infection in the U.S. and is the most common reason for liver transplantation. Currently, it is estimated that there are 170 million people infected worldwide with HCV and about 4 million people infected in the U.S. HCV genotyping is an FDA-mandated requirement for prescribing drug therapy for HCV in the USA. In most studies, patients with type 2 or 3 HCV have at least a three-fold better response to treatment than those with type 1. In the U.S., HCV genotype 1 predominates while types 2 and 3 have also been identified.



The TRUGENE HCV 5'NC genotyping test sequences a portion of the viral genome. There are six major types and more than 90 subtypes of HCV that have been recognized to date. Research is continuing on the clinical use of this sequencing information in the assessment, and management of HCV infected patients. As specific hepatitis drugs come to market, the role of HCV drug resistance genotyping will become more important in the clinical management and prognosis of HCV infection.



Research continues on the clinical use of this sequencing information in the assessment and management of Hepatitis B and C infected patients.



About the Company



Visible Genetics Inc. is an international leader in the emerging field of pharmacogenomics, which uses genetic information in the identification and analysis of genes to improve patient care and reduce healthcare costs. VGI develops, manufactures and markets high performance automated DNA sequencing systems and complete kits for the analysis of genes linked to disease. The Company's OpenGene system employs patented CLIP technology -- a single-step, bi-directional sequencing method that significantly reduces the time and cost involved in identifying clinically relevant genetic information. Visible Genetics' TRUGENE HIV-1 Genotyping Test and OpenGene DNA Sequencing System were cleared for sale in September 2001 by U.S. Food and Drug Administration (FDA).



Visible Genetics has its corporate headquarters in Toronto, Canada; its main production facility in Atlanta, USA; its European headquarters in High Wycombe, UK, its research base in Cambridge, UK, operating companies in France, Spain, Italy, Germany, Portugal, Switzerland, Israel and Australia, and is represented in 10 additional countries around the world. The company employs approximately 350 people worldwide.



This press release contains forward-looking statements within the meaning of the ``safe harbor'' provisions of the Private Securities Li