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HIV Drug Resistance Test More Descriptive Than Ever - Virco Launches New HIV Resistance Report

Posted on: Monday, 1 August 2005, 12:01 CDT

RARITAN, N.J., Aug. 1 /PRNewswire/ -- Addressing the need for a more complete assessment upon which to base HIV treatment decisions, Virco BVBA, a leader in drug-resistance testing, is rolling out the virco(R)TYPE HIV-1 resistance analysis with clinical cutoffs. Described as a report card that includes a grade point average with comprehensive teacher notes instead of a pass/fail grade, the virco(R)TYPE HIV-1 analysis integrates genotypic and phenotypic findings along with expert clinical knowledge - all in one cohesive, easy-to-interpret report.

"The virco(R)TYPE HIV-1 shows how resistant a virus is along a continuum that includes lower and upper clinical cutoffs. Ultimately, this enables doctors to discover treatment options that might otherwise have been unidentified by conventional resistance tests," said virologist Lee Bacheler, PhD, of Virco, who helped present key scientific information on virco(R)TYPE HIV-1 during the recent International AIDS Society Conference in Rio de Janeiro.

For the nearly half million Americans with HIV taking highly active antiretroviral therapy (HAART), which is usually comprised of a combination of 3 or more drugs, resistance to HIV drugs is very much a reality - a reality that cannot be reversed once it develops. Worse yet, resistance to one drug may render an entire class of HIV drugs powerless against the virus, a condition known as cross-resistance.

When resistance develops - as it has in 25%-50% of the patients on HAART - switching to another combination of drugs is necessary to once again suppress viral replication and, ultimately, to prevent HIV from progressing to AIDS. Before the advent of resistance testing, determining which combination of drugs to switch to was based solely on a patient's history. Currently, "genotypic" testing is available to identify particular resistance-causing mutations in a virus's genome. Doctors can also order a "phenotypic" test for a direct measure of resistance, which is obtained by exposing viral isolates to increasing concentrations of individual drugs in the laboratory - an expensive and time-consuming process. Both tests have limitations. Genotypic assays measure resistance indirectly. Phenotypic tests are considerably more expensive and have only recently started including relevant breakpoints that reflect how the drugs work in patients treated in the clinic. Consequently, the information each test provides is useful, albeit incomplete. Even with both tests, it can be a challenge to identify drugs that are likely to work in patients with a high level of multi-drug resistance, an ever-increasing phenomenon.

The virco(R)TYPE HIV-1 also standardizes the measure of how each drug's therapeutic value is compromised by viral resistance when used in HAART. According to Bacheler, the reference clinical cutoff values for all of the drugs were derived from a large database combining treatment history, resistance and treatment response information using a common methodology. "For this reason, our reference values are applicable to a broad range of patients and relevant to the way doctors practice medicine," Bacheler concludes.

In contrast, conventional phenotypic results are based on either biological cutoffs established by determining how the HIV virus responds in the laboratory or by clinical cutoffs established by different laboratories using different methodologies within small, select patient populations. Edwin DeJesus, MD, Medical Director of the Orlando Immunology Center, says, "Several studies have demonstrated the value of clinical cutoffs in evaluating HIV drug resistance. In clinical practice, these clinical cutoffs represent a more reliable approach to interpreting resistance information."

According to Dr. DeJesus, "As multi-drug resistance becomes increasingly common, virco(R)TYPE-HIV-1 represents a very useful and unique tool that provides consistent, clinically relevant information and, most importantly, has a higher degree of correlation with clinical outcomes. Because this analysis takes into account the effects of drugs used in combination therapy, the results obtained are closely related to actual treatment practices. The therapeutic decisions made based on this analysis are more likely to positively influence the medical management given to our patients."

Providing real-time reporting for quicker access to information, the analysis is usually completed and available to the lab or hospital within 10 to 30 minutes after a genotype has been done and for a fraction of the cost of a phenotype.

Virco BVBA is a world leader in the field of HIV resistance testing services for clinical practice and clinical studies, advancing research that correlates laboratory testing with clinical management, while offering a wide range of HIV resistance diagnostics. The company applies the latest technologies in molecular biology, medical virology and bio-informatics to develop advanced diagnostic tools that are based on pharmacogenomic principles of individualized patient care. A pioneer in HIV resistance testing, Virco has one of the world's largest repositories of HIV clinical isolates, a database of more than 68,000 phenotypes and more than 203,000 genotypes, and cutting- edge bio-informatics capabilities.

Contact: Amy Maggio ANM Healthcare Solutions phone: 312 840 9291 amy.maggio@mccann.com Philippe Alen, PhD Virco BVBA phone: +32 15 293 150 palen@vrcbe.jnj.com

This release was issued through eReleases(TM). For more information, visit http://www.ereleases.com/.

Virco BVBA

CONTACT: Amy Maggio of ANM Healthcare Solutions, +1-312-840-9291,amy.maggio@mccann.com, or Philippe Alen, PhD of Virco BVBA, +32 15 293 150,palen@vrcbe.jnj.com

Source: PRNewswire

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