Dec. 6, 2000 -- A newly-developed form of interferon -- the gold standard for treating hepatitis C infection -- may offer hope for the nearly three million U.S. patients suffering from the chronic, potentially liver-destroying disease.
Researchers have found that by attaching a specialized molecule to the basic form of interferon, they can create a longer-lasting drug that patients need less of, less often. And peginterferon, as it's called, produces equally good, or even better, results.
The new findings and an accompanying editorial appear in the Dec. 7, 2000 issue of The New England Journal of Medicine.
This is a way of manipulating a drug to make a current treatment better, editorialist Daniel F. Schafer, MD, tells WebMD. "Although it may seem like a small thing in hepatitis C, it will make things easier and better for patients. The side effects are similar to existing therapies, and they only have to take a shot once a week instead of three times per week or even every day. And," he adds, "it works better." Schafer is associate professor of medicine and an expert in adult liver disease and transplant at the University of Nebraska Medical Center, in Omaha.
In the first of the two studies, Stefan Zeuzem, MD, and colleagues randomly assigned nearly 550 chronic hepatitis C patients to weekly injections of the new drug or to standard interferon injections three times a week, for 48 weeks. The therapy was deemed successful if tests could not detect hepatitis C virus in a patient's blood after 72 weeks.
About 10% of patients in both groups withdrew from the study due to similar side effects -- mainly fatigue, depression, and blood disorders. But overall, compared to those given the standard interferon treatment, significantly more patients who'd taken peginterferon had undetectable amounts of the virus in their blood.
In the second study, E. Jenny Heathcote, MD, and colleagues randomly assigned nearly 300 hepatitis C patients who had already developed liver disease called cirrhosis to either standard treatment, or to low or high doses of peginterferon, again for 48 weeks.
As in the first study, these researchers were hoping to find undetectable amounts of virus in the blood. In this study, they also looked at several patients' liver cells. All treatments were equally well tolerated.
Again, more patients taking peginterferon than taking standard interferon had reduced virus counts in their blood. What's more, their liver cells also looked significantly better.
Schafer and co-editorialist Michael F. Sorrell, MD, call the results of both studies "encouraging," noting that even patients with no decrease in the amount of virus in the blood may still have less liver damage with either interferon or peginterferon.
Another significant benefit of these drugs, Schafer tells WebMD, is that "even if you don't respond, there's evidence that it decreases your chances of getting a certain type of liver cancer -- hepatocellular carcinoma -- that is believed to be a long-term effect of hepatitis C infection."
They caution, however, that peginterferon may not benefit all patients. Even this improved formulation may be insufficient against the highly-interferon resistant genotype 1 hepatitis C strain carried by about 75% of infected patients in the U.S. In both studies, the response rate was much lower for those with this resistant strain than it was for those with other strains of the virus.
Also, Schafer tells WebMD, more research is needed to determine whether black patients, who were underrepresented in these studies despite comprising a large proportion of those with hepatitis C, will have a similar rate of response as other racial and ethnic groups.
Peginterferon is not yet on the market, but FDA approval is pending.