Women in the Republic infected with the hepatitis C virus through contaminated blood products have a greater prognosis than hepatitis C patients in other countries, according to two US experts on the disease.
Dr Jay Hoofnagle, director of liver disease research at the National Institute of Health, Maryland, told the international conference on hepatitis C that the virus is an insidious invader of the human body, both because of the damage it can do but also because its presence is not recognised early enough in many patients who develop chronic liver disease. "Hepatitis C virus replicates in liver cells and persistent infections, appears to rely upon rapid production of virus and continuous cell-to-cell transmission of virus," he said.
Emphasising there were no accurate studies of the numbers of people who went on to develop chronic hepatitis, Dr Hoofnagle said estimates put the figure at 75-85 per cent of patients who develop acute hepatitis C. "Patients over 40 years of age with chronic hepatitis C have a 10 per cent chance of developing liver cirrhosis per decade, a figure which drops to 2-5 per cent per decade in the under-40s." He pointed out that cancer of the liver, which develops in 25 per cent of hepatitis C patients, is one of the few cancers in the world on the increase.
Dr John McHutchinson, director of hepatology research at Duke Clinical Research Institute, North Carolina, told the meeting that current therapies against hepatitis C are effective in over half of all treated patients. "But existing treatments can cause significant side effects, are unsuitable for many patients and can be costly."
Pointing out that the ideal treatment is one that could be taken orally, be safe and effective and not associated with disease resistance, Dr McHutchinson said interferon-based treatments, using peginterferon and ribavirin, are likely to remain the mainstay for the next decade. "Testing drug response early during therapy at week 12 is an important recent improvement as a way to accurately predict who is likely to achieve a sustained response to treatment," he said, adding that it can be difficult to decide who should get treatment because of the wide range of individual responses.
"Current treatments prevent liver cancer and improve quality of life but we are unsure if it prevents cirrhoses or reduces the need for liver transplant," he said; 20 per cent of patients cannot tolerate interferon-based treatment and up to 50 per cent of people need to have the dose reduced because of side effects.
Turning to future therapies for hepatitis C, he said researchers are looking to develop a vaccine. "Another approach is the development of HCV specific viral enzyme inhibitors that knock out enzymes essential for viral replication and there have been some early encouraging results associated with this." New combined therapies should significantly increase the response rates and diminish the level of side effects.
At a parallel patient session, Dr Graham Foster, consultant hepatologist at the Royal London Hospital, delivered a well-received lecture: "Viral infections and the immune response: friends or foes." He said: "Patients with hepatitis C virus with mild disease feel just as bad as patients with severe disease. We need to work together - clinicians, scientists and patients - to find out why this is."