PR Newswire -- August 4, 2008
KENILWORTH, N.J., Aug. 4 /PRNewswire-FirstCall/ -- Schering-Plough Corporation (NYSE: SGP) today reported top-line results from a planned interim analysis of a Phase II study of boceprevir, its investigational oral hepatitis C protease inhibitor. The analysis showed a high rate of sustained virologic response (SVR) in patients receiving boceprevir-based combination therapy in this study of 595 treatment-naive patients with chronic hepatitis C virus (HCV) genotype 1.
In a 48-week treatment regimen, the SVR rate at 12 weeks after the end of treatment (SVR 12) was 74 percent (ITT) in patients who received 4 weeks of PEGINTRON(TM) (peginterferon alfa-2b) and REBETOL(R) (ribavirin, USP) prior to the addition of boceprevir (800 mg TID) (P/R lead-in), compared to 38 percent for patients in the control group receiving 48-weeks of PEGINTRON and REBETOL alone.(1-3)
Patients in the study who received 48-weeks of boceprevir in combination with PEGINTRON and REBETOL from the beginning of treatment (no P/R lead-in) achieved 66 percent SVR 12.
In the two 28-week boceprevir arms of the study, SVR at 24 weeks after the end of treatment (SVR 24) was 56 percent and 55 percent for patients in the lead-in and no lead-in arms, respectively.
Importantly, for patients who received the PEGINTRON and REBETOL lead in and had rapid virologic response (RVR), defined as undetectable virus (HCV-RNA) in plasma after 4 weeks of boceprevir treatment, SVR
(ITT) was 82 percent in the 28-week regimen and 92 percent in the 48 week regimen.
"These top-line results with boceprevir are very exciting, especially given that genotype 1 is the most common and hardest to treat form of hepatitis C," said Paul Kwo, M.D., associate professor of medicine and medical director, liver transplantation, Department of Medicine, Division of Gastroenterology/Hepatology, Indiana University School of Medicine, Indianapolis, and lead investigator of the study. "Boceprevir was well tolerated by patients in this study, including those who received 48 weeks of boceprevir in the longer duration treatment arms."
Safety data from the study showed that the most common adverse events reported in the boceprevir arms were fatigue, anemia, nausea and headache. No increase in skin adverse events (rash or pruritus) beyond what was seen in the PEGINTRON and REBETOL control arm was observed.
Treatment discontinuations due to adverse events were between 9 and 19 percent for patients in the boceprevir arms, compared to 8 percent for the control arm.
In the study, known as HCV SPRINT-1 (HCV Serine Protease Inhibitor Therapy-1), boceprevir (800 mg TID) was evaluated in three treatment
regimens: 4 weeks of PEGINTRON (1.5 mcg/kg once weekly) and REBETOL (800-1400 mg daily based on patient weight) therapy followed by the addition of boceprevir to the combination for 24 or 44 weeks (totaling
28 or 48 weeks of treatment); boceprevir in combination with PEGINTRON and REBETOL at the doses described above for 28 or 48 weeks; and boceprevir in combination with PEGINTRON and low-dose REBETOL (400-1000 mg daily) for 48 weeks, compared to a control of PEGINTRON (1.5 mcg/kg once weekly) and REBETOL (800-1400 mg daily based on patient weight) alone for 48 weeks (an approved treatment regimen). The primary endpoint of the study is SVR after 24 weeks of follow up (SVR 24). This is an ongoing study and SVR 24 rates are not yet available for patients in the 48-week boceprevir arms or the 48-week control arm of the study.
Sustained Virologic Response (ITT)*
Treatment Arm All patients
No P/R Lead-in 28 Weeks 55% (59/107)
P/R Lead-in 28 Weeks 56% (58/103)
No P/R Lead-in 48 Weeks 66% (68/103)
