Source: University of British Columbia
UBC Discovery Reverses Thinking About Hep C Treatment for Drug Users
November 8, 2006
Contrary to current practice, treating injection drug users (IDUs) for Hepatitis C virus (HCV) may reduce suffering and health-care costs, according to University of British Columbia researchers.
HCV treatment is regularly denied to IDUs because of concerns over adherence to treatment and re-infection due to recurrent risk behaviours, such as shared needles.
The researchers demonstrated that IDUs who spontaneously recover from HCV infection have a lower risk of re-infection despite continued exposure to the virus.
The study, published in the November issue of Hepatology, is the first Canadian research to offer evidence that previously infected IDUs whose virus cleared without treatment, may be at lower risk -- four times less likely -- of HCV re-infection than previously expected. The study involved a greater number of participants than any previous U.S. study, according to the investigators.
In a related study, the researchers also explored if protection against re-infection extends to IDUs who are treated for the virus. The findings suggest the same protective effect exists, offering important implications for future therapies, say the researchers.
The study of 40 current and former IDUs at the Pender Community Health Centre in Vancouver and the Cool Aid Community Health Centre in Victoria, indicated that IDUs treated within a multi-disciplinary care program can achieve cure rates similar to those seen in large, randomized controlled trials, despite continued drug use. Findings were presented at the 17th International Conference on Reduction of Drug Related Harm, held in Vancouver in April 2006.
"Findings from both studies reverse existing thinking and hold real promise for treating this population that is contracting HCV at almost epidemic rates in many urban centres, including Vancouver," says Jason Grebely, UBC PhD candidate in the Dept. of Anesthesiology, Pharmacology and Therapeutics.
HCV affects an estimated 123 million people worldwide with more than half of existing cases and more than 90 per cent of new cases occurring in IDUs. About 20 per cent of patients spontaneously clear the infection. Many people do not have symptoms until their liver has been seriously damaged. Symptoms include jaundice, abdominal pain, fatigue and nausea. Treatment involves a rigorous six-month to one-year treatment regimen that results in a cure in about half of patients treated.
Untreated HCV can cost an estimated $24,000 annually per patient to manage complications of chronic infection, such as liver disease (cirrhosis) and liver cancer.
In the study published in Hepatology, Grebely and his supervisor, Assoc. Prof. Brian Conway, of UBCís Dept. of Anesthesiology, Pharmacology and Therapeutics, along with Assoc. Prof. Mark Tyndall of UBCís Dept. of Medicine and the British Columbia Centre for Excellence in HIV/AIDS, led an analysis of more than 1,400 individuals in Vancouverís Downtown Eastside.
"We were surprised to find that previous exposure to HCV may have some protective effect, despite repeated exposure to the virus," says Conway. "The discovery paves the way for a systematic and comprehensive approach to treatment and control of this epidemic."
The researchers compared the rate of re-infection in individuals with spontaneous clearance of the virus between 1992 and 2005, to the rate of infection among those infected for the first time.
Results showed that those with previous HCV infection and spontaneous viral clearance were four times less likely to become re-infected than those infected for the first time, even when they continued to expose themselves to the virus through injection drug use.
Health data for this study has been supplied by Tyndall, through the Community Health and Safety Evaluation (CHASE) project, funded by Vancouver Coastal Health. Research support was also provided by Dr. Mel Krajden at the B.C. Centre for Disease Control (BCCDC).
UBC Faculty of Medicine researchers attracted more than $203.7 million in funding in 2005/2006 for more than 2,600 projects.
Vancouver Coastal Health is responsible for the delivery of $2.1 billion in community, hospital and residential care to more than one million people in communities from Richmond to Bella Coola.
An agency of the Provincial Health Services Authority, BCCDC is B.C.ís Centre of Excellence for the prevention, detection and control of communicable disease, and a provider of specialty health support and resource services.
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