Hepatitis B Viral Load Measurement Improves
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Infecting about two billion people worldwide each year, the Hepatitis B virus (HBV) is one of the most serious types of viral hepatitis. Over the past decade, a variety of medications have been developed and approved to help those with HBV – however, the drugs rarely provide a cure. To determine if their treatment is working and how severe their illness is, physicians continually monitor their patients’ viral load. In September of 2008, the U.S. Food and Drug Administration (FDA) approved a new, more sensitive test to determine HBV viral load in an effort to improve the HBV monitoring process.
Hepatitis B Treatment
Although they usually do not eliminate the virus, the FDA has approved seven drugs for treating chronic HBV. In order for a treatment to be considered a cure, the affected individual must have a loss of Hepatitis B virus from their body and must have developed protective antibodies against it. Despite the lack of totality, these drugs have been shown to significantly decrease the risk of liver damage from HBV by slowing down or stopping the virus from reproducing. Aside from the interferons, most of the medications must be taken for at least a year. The approved Hepatitis B drugs include:
- Interferon Alpha – approved in 1991
- Pegylated Interferon – approved in 2005
- Lamivudine – approved in 1998
- Adefovir Dipivoxil – approved in 2002
- Entecavir – approved in 2005
- Telbivudine – approved in 2006
- Tenofovir – approved in 2008
When progressing with one of the above HBV treatments, doctors test their patients’ viral load:
- to establish a baseline level of infection
- during treatment as an aid in assessing the person’s response to therapy.
Viral Load Test
Because the goal of Hepatitis B therapy is to treat until the virus is undetectable, it is critical for viral load monitoring tests to be able to quantify very low levels of virus. Similarly, it is important for the test to quantify very high levels of virus (higher than 100 million IU/mL), an indicator of the need for more or less aggressive treatment.
A collective analysis of tests is used to determine a person’s HBV viral load. Joining the existing biochemical and serological viral load tests, Roche’s COBAS Taqman HBV Test has just been approved as the first nucleic acid HBV test. The first assay for quantifying HBV DNA in the U.S, the COBAS Taqman test uses real time PCR technology to determine the amount of Hepatitis B virus DNA present. By providing a significantly broader range of detection, this new technology fosters a more exact calculation of the amount of Hepatitis B virus in a person’s body.
Daniel G. Schultz, M.D., director of the FDA’s Center for Devices and Radiological Health says, “Measuring a patient’s HBV viral load is an important aspect of managing chronic Hepatitis B infections. The COBAS TaqMan test gives health care providers a new and sensitive tool for this process.”
Roche’s nucleic acid assay will help physicians fine tune HBV treatment. Knowing more specifically how much HBV is in a person’s body can better guide the therapeutic process. Although improving HBV monitoring may not seem like a big deal, it brings the likelihood of an HBV cure closer within modern medicine’s reach.
References:
http://www.biospectrumasia.com/content/050908OTH7019.asp, Roche gets FDA approval for its Hepatitis B viral load test, Retrieved September 12, 2008, BioSpectrum, September 2008.
http://www.fda.gov/bbs/topics/NEWS/2008/NEW01880.html, FDA Approves DNA Test to Measure Hepatitis B Virus Levels, Retrieved September 12, 2008, US Food and Drug Administration, September 4, 2008.
http://www.hepb.org/patients/hepatitis_b_treatment.htm, Approved Drugs for Adults, Retrieved September 14, 2008, Hepatitis B Foundation, 2008.
http://www.hivandhepatitis.com/hep_b/news/2008/090908_a.html, FDA Approves First Hepatitis B Viral Load Test, Retrieved September 12, 2008, Roche press release, hivandhepatitis.com, September 2008.
http://www.hospitalbuyer.com/medical-specialties/hematology-oncology
/hep-b-viral-load-test-cleared-2827/, Hep B Viral Load Test Cleared, Retrieved September 12, 2008, Watershed Publishing, LLC, 2008.
http://www.news-medical.net/print_article.asp?id=41212, FDA approves DNA test to measure hepatitis B viral load, Retrieved September 14, 2008, News-medical.net, September 2008.
