NEW YORK--Aggressive new interferon (IFN) treatment strategies aimed at combating chronic hepatitis C virus (HCV) infection are roughly twice as effective as the standard thrice-weekly, six-month IFN regimen.
"A 12-month to 18-month course of Intron A [IFN alfa-2b] nearly doubles the sustained response among HCV patients," Robert G. Gish, MD, said during a press briefing funded by an educational grant from Schering Oncology Biotech.
Dr. Gish is medical director of the Liver Transplant Program at the California Pacific Medical Center, San Francisco.
Left untreated, HCV infection can result in cirrhosis, and once cirrhosis has begun, current treatment regimens are unlikely to clear the virus, he said. However, recent data suggest that treating HCV-infected cirrhotic patients with IFN may decrease their risk of developing liver cancer and delay the time to death or transplantation. Thus, he suggests aggressive IFN therapy for patients with early cirrhosis.
"Among cirrhotic patients with liver cancer, the five-year survival rate is only about 5% to 20%," Dr. Gish said. However, patients with this lethal disease combination have approximately an 80% survival rate if liver transplant is performed. Unfortunately, many of these patients are not candidates for transplant because their liver tumors exceed 10 cm.
Overall, he said, the management of HCV infection is promising given IFN's proven efficacy and new combination treatments. Slow-release polyethylene glycol (PEG)-bound IFN formulations under development may prove useful, since they offer a convenient once- or twice-weekly dosing schedule.
Combination HCV Therapies Emerging
Ribavirin (Virazole), a guanine nucleoside analog approved in the US for use as a pediatric aerosol treatment for respiratory syncytial virus, is now being evaluated in combination with interferon alfa-2b(Drug information on interferon alfa-2b) (Intron A) for HCV treatment.
Although the mechanism for the favorable synergistic effect is not yet understood, there appears to be an immunomodulatory action that maintains or stimulates cell-mediated immune function.
Approximately 40 US trials of the combination are underway in HCV patients who failed conventional IFN therapy. One study of 50 IFN-naïve HCV patients, presented at the press conference by Douglas Dietrich, MD, of New York University, showed that combination therapy doubled the response rate, compared with IFN alone.
After six months of treatment, 52% of patients in both groups had no detectable HCV. After another six months of follow-up, 36% of those receiving combination therapy remained without detectable viral levels versus 18% of the mono-therapy patients.
Said Dr. Gish: "HCV therapy must be started early in the disease process, be aggressive, and continue for the long-term. It is important for all physicians to realize that this approach will improve survival, and even cure the disease in many cases."