Reuters Health Information (2008-11-04): New protease inhibitor doubles treatment response rates in HCV infection
New protease inhibitor doubles treatment response rates in HCV infection
Last Updated: 2008-11-04 13:42:23 -0400 (Reuters Health)
SAN FRANCISCO (Reuters Health) - In patients with treatment-naive chronic hepatitis C virus (HCV) genotype 1 infection, the investigational protease inhibitor boceprevir (Schering-Plough) produces sustained viral response rates that are nearly twice that seen with the standard of care.
"The high response rates seen with boceprevir in this study are very exciting, especially given that genotype 1 is the most common and hardest to treat form of hepatitis C," said principal investigator Dr. Paul Kwo of Indiana University in Indianapolis. He announced results of the HCV SPRINT-1 (HCV Serine Protease Inhibitor Therapy-1) study at the annual meeting of the American Association of the Study for Liver Diseases, which is being held here this week.
HCV SPRINT-1 study is a five-arm trial of boceprevir 800 mg plus the standard of care with pegylated interferon alfa 2b (1.5 mcg/kg once a week) plus ribavirin, 800-1400 mg daily, involving 595 patients with HCV-1.
The five treatment regimens were:
- a four-week lead-in with interferon and ribavirin followed by 24 weeks of triple therapy with boceprevir, and 44 weeks of follow-up;
- four weeks of interferon and ribavirin, followed by 44 weeks of triple therapy and 24 weeks of follow-up;
- 28 weeks of triple therapy and 44 weeks of follow-up;
- 48 weeks of triple therapy and 24 weeks of follow-up; and
- a control arm of 48 weeks of the standard of care with interferon and ribavirin and 24 weeks of follow-up.
Sustained viral response (SVR) rates after follow-up were 38% in control patients, 55% with 28 weeks of triple therapy, 56% with 24 weeks of triple therapy and four weeks of interferon and ribavirin, 66% with 48 weeks of triple therapy and 74% with 44 weeks of triple therapy following 4 weeks of interferon and ribavirin.
"The best results were with a four-week run-in phase...then adding boceprevir for 44 weeks. There is a rapid virologic response and a sustained viral response. The response rates are almost double those with the standard of care," Dr. Kwo pointed out.
The rapid viral response makes patients want to continue with treatment, Dr. Kwo told Reuters Health, "and we can begin using the word 'cure' in these patients."
"Achieving a rapid response is important. Patients are motivated to continue with therapy, to adhere to treatment, if they know they can be cured within 48 weeks. This is important in achieving a sustained viral response."
"HCV doesn't have a latent phase, like HIV or Herpes zoster, so if we can get a sustained virologic response, we can start using the word 'cure'," he said.
"We might even be able to change the outcome (of HCV infection) with successful treatment. We've seen a dramatic reversal of fibrosis and in some case a reversal of cirrhosis with sustained virologic response."
Dr. Kwo said the rates of adverse events with triple therapy "are not different" from ribavirin and interferon alone. He noted that interferon is the drug that causes the most significant side effects, "but if patients see that treatment is working and there is an end in sight, they are more likely to adhere to treatment."