Science/Medicine : Interferon and Hepatitis: Separating Hype From Hope
In recent months, encouraging reports about the use of interferon to treat patients with chronic viral hepatitis have been widely publicized. But many specialists in liver disease remain uncertain of the significance of the findings and caution that claims of a “cure” are exaggerated.
The case of interferon is only the latest illustration of a recurrent problem for physicians and the press--how to present news of medical advances with accuracy, not hype. The situation arises most frequently with developments in the fights against AIDS and cancer. It is also a factor with other serious diseases.
Words like breakthrough or cure too often adorn press accounts about medical progress. In reality, the accomplishments often are significant, but far less dramatic.
Many patients view interferon “like penicillin for pneumonia,” said Dr. John Lake, the medical director of the liver transplant program at the UC San Francisco Medical Center. “People don’t understand that less than half of the patients respond and that there are significant side effects.”
A close reading of the interferon studies and interviews with liver specialists reveal many caveats.
The patients who have improved will have to be followed for years before the long-term benefits of interferon can be determined. The best dosage and duration of treatment are not known. Information about the types of patients most likely to benefit is incomplete. Some responders relapse after the treatments are stopped.
The experimental treatments consist of repeated injections of recombinant alpha interferon, a naturally occurring human protein that is produced in large quantities through genetic engineering techniques. Patients are taught how to administer the injections themselves. A typical course of treatment costs thousands of dollars.
More than half of patients treated with interferon have flu-like symptoms, such as fevers, headaches and muscle aches. These symptoms often improve with non-prescription pain medicines and diminish as treatment continues. Some patients must stop treatment because they develop low white blood cell or platelet counts.
Although the U.S. Food and Drug Administration has not approved interferon treatments for chronic viral hepatitis, physicians are free to prescribe them. This is because alpha interferon is already marketed in the United States for the treatment of a rare leukemia, genital warts and AIDS-related Kaposi’s sarcoma.
Interferons can both boost the body’s immune system and interfere with the ability of viruses to reproduce. In chronic viral hepatitis, laboratory measures of abnormal liver function can improve or return to normal. Symptoms, such as fatigue, may improve. Many patients, however, have no symptoms.
Interferon has beneficial effects against both hepatitis B and hepatitis C, the two most common forms of chronic viral hepatitis.
Chronic hepatitis B infection is the chief cause of liver cancer and cirrhosis, or liver scarring, in the world. About 10% of individuals infected with the hepatitis B virus develop chronic infections, said Dr. Gary Gitnick of the UCLA Medical Center.
Hepatitis C infection is the chief cause of hepatitis after blood transfusions in the United States and a frequent cause of sporadic hepatitis cases. Between 40% and 70% of those infected with hepatitis C through blood transfusions develop chronic infections, Gitnick said. Many progress to cirrhosis.
Significantly lower doses of medication appear to be effective against hepatitis C than with hepatitis B. Thus, interferon side effects are less frequent in hepatitis C patients, Lake said.
A study in the New England Journal of Medicine, published in August, included some of the most favorable results to date. About one-third of the 126 hepatitis B patients treated with interferon went into remission. In 11 of the 38 responders, the researchers were unable to find any evidence of hepatitis B virus DNA.
This implies--but does not prove--that the viral infection had been eliminated from their bodies. In comparable studies, there is no such evidence for the elimination of hepatitis C virus.
But the long-term significance of these findings is unclear. This is why liver specialists urge caution in interpreting the results.
One possibility is that the hepatitis B virus remains in the body of patients at very low levels, said Dr. Alexandra Read of the UC San Francisco Medical Center. If this is the case, the virus might eventually begin to multiply and cause health problems.
Another concern, cited by Gitnick, is that even if the hepatitis B virus has been eliminated, patients may already have developed self-sustaining liver damage, which can progress to cirrhosis and liver cancer.
So while the results, indeed, are encouraging, a cure for chronic viral hepatitis is by no means at hand. It is a delicate balance--providing hope to chronically ill patients without creating false expectations.
