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Boceprevir Phase II Study Showed High Rate of Sustained Response With 28- and 48-Week Regimens in Genotype 1 Treatment-Naive Hepatitis C Patients

Another article from AASLD...

Boceprevir Phase II Study Showed High Rate of Sustained Response With 28- and 48-Week Regimens in Genotype 1 Treatment-Naive Hepatitis C Patients
Saturday, November 01, 2008 11:00 AM


Interim results of HCV SPRINT-1 study presented at AASLD annual meeting

Pivotal Phase III studies ongoing in treatment naive patients and those who failed prior treatment

SAN FRANCISCO, Nov. 1 /PRNewswire-FirstCall/ -- Schering-Plough Corporation (NYSE: SGP) today reported that a planned interim analysis of a Phase II study showed that boceprevir, its investigational oral hepatitis C protease inhibitor, in combination with peginterferon and ribavirin markedly increased sustained virologic response (SVR) rates with 28 weeks of therapy and nearly doubled SVR with 48 weeks of therapy compared to current standard of care, peginterferon and ribavirin (control group) for 48 weeks. These results from the HCV SPRINT-1 study in 595 treatment-naive patients with chronic hepatitis C virus (HCV) genotype 1 were presented at the 59th American Association for the Study of Liver Diseases (AASLD) Annual Meeting.(1)

In a 48-week boceprevir regimen, the SVR rate was 74 percent at 12 weeks after the end of treatment (SVR 12) 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). In a 28-week boceprevir regimen, the SVR rate was 56 percent at 24 weeks after the end of treatment (SVR 24) in patients who received the P/R lead-in. These results compared to a 38 percent SVR rate (SVR 12) for patients in the control group receiving 48-weeks of PEGINTRON and REBETOL alone (ITT).(2-4)

Importantly, predictability of attaining SVR 12 or 24 based on rapid virologic response (RVR) was greater for boceprevir patients in the lead-in arms compared to the no lead-in arms. In addition, fewer patients in the lead-in arms discontinued treatment due to viral breakthrough. RVR is defined as undetectable virus (HCV-RNA) in plasma on or before week 4 of boceprevir treatment.

'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 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, and the use of the 4-week lead-in prior to the addition of boceprevir appears to reduce the incidence of viral breakthrough regardless of treatment duration and may improve SVR over a 48-week treatment period.'

The rationale for this novel lead-in treatment regimen is based on the fact that both PEGINTRON and REBETOL reach steady-state concentrations by week 4, so patients have the protease inhibitor added at a time when the backbone drug levels have been optimized. In addition, the patient's immune system will have been activated and primed by PEGINTRON at the time that boceprevir is added to the regimen. This approach may minimize the period of time when there is a 'functional monotherapy' with a direct antiviral, potentially reducing the likelihood for the development of resistance.

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) was observed in the boceprevir arms beyond what was seen in the PEGINTRON and REBETOL control arm.

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. Treatment discontinuations for boceprevir patients due to viral breakthrough were fewer in the 28- and 48-week lead-in arms (4 and 5 percent, respectively) compared to the no lead-in arms (7 and 11 percent, respectively).

About the HCV SPRINT-1 Study

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Avatar universal
Continues... Follow link for more.

In this Phase II 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, in Part II of the study, boceprevir in combination with PEGINTRON and low-dose REBETOL (400-1000 mg daily based on patient weight) 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. In addition, SVR rates are not yet available and consequently results are not being reported for the boceprevir arm with low-dose REBETOL (n=59) compared to contemporaneous control (n=16) as described above.

                     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)
          P/R Lead-in 48 Weeks                    74% (76/103)
          P/R Control 48 Weeks                    38% (39/104)

        P/R Lead-in = PEGINTRON and REBETOL for 4 weeks prior to the addition of boceprevir
        P/R Control = PEGINTRON and REBETOL alone for 48 weeks
        * SVR 12 for 48 week arms; SVR 24 for 28 week arms(2-4)

In the study, predictability of attaining SVR (12 or 24) based on rapid virologic response (RVR) following 28 or 48 weeks of the boceprevir regimen was greater for patients in the lead-in arms (82 and 92 percent respectively) compared to the no lead-in arms (74 and 82 percent, respectively).

The HCV SPRINT-1 study was conducted at sites across the United States, Canada and Europe. Overall, 77 percent of the 595 patients in the study were enrolled in the United States. African-Americans represent 16 percent of the patients enrolled and 7 percent of patients in the study are cirrhotic.

Update on Boceprevir Phase III Studies

Schering-Plough is conducting two large ongoing pivotal Phase III studies of boceprevir in patients chronically infected with HCV genotype 1. One study is in treatment-naive patients and the other in patients who failed prior treatment (relapsers and nonresponders). The two randomized, double-blind, placebo-controlled studies evaluate the efficacy of boceprevir in combination with PEGINTRON and REBETOL compared to standard of care with PEGINTRON and REBETOL alone.

The study in treatment-naive patients is known as HCV SPRINT-2 and the study in patients who failed prior treatment is known as HCV RESPOND-2. The two studies are expected to enroll a total of more than 1,400 patients at U.S. and international sites.

408795 tn?1324939275
Good information, especially since I got my start date.  I start in 10 days and I'm totally looking forward to it, right now anyways, and I don't expect that to change. lol  I hope the sx nazi's are good to me.  lol  Are you starting soon?  good luck
Avatar universal
I still like telaprevir because it shows similar results with just 24 weeks of  treatment.
Avatar universal
Thanks for the information.  I'm seriously thinking about the Boceprevir with this lead-in for my next treatment down the road.  Not sure if I want to participate in a trial...., too many things to consider.  Do I really want to go through the additional headaches of a trial?  Will it even be offered at one of the trial sites that I'm already linked up with?  Would I even be accepted into another trial as I am not really a good risk for their stats, you know?  I really couldn't believe that the idea of trying to treat again with the Telaprevir would turn out any differently for me as, I've already been exposed to the Telaprevir and have resistance-probably and there's the bad rash that I had before.  I'm not ruling out trying it again down the road..., but I like the idea of Boceprevir better.  Also, I also had a better response on the Peg-Intron regimens than on the Pegasys.  The Pegasys may have less sides, but it also doesn't work as well in my body.  I'd also be interested in having the opportunity to try something like Infergen along with Riba and one of these inhibitor drugs-either Boceprevir or Telaprevir - but that would not be able to happen without doing it outside of the trial regimens because each company would rather use their own type of interferon.  Now see, if I were to wait until one of them was FDA approved AND-(this is a BIG AND), I'd even have insurance willing to pay for them, then it would be worth looking into it.    I just hope my body can hold out while these drugs are fine tuning all this process!!

Avatar universal
Susan...i wish i was a tough as you.....you talk about this TREATMENT like it dont even fizz on you...my God...i think if i did as much as you did i would be ,well i waont say...LOL...more power to ya my Dear.
Avatar universal
Fret... Don't have a definate start date, but should have one by the end of the week. It will be within the next two to four weeks. I am also looking forward to the start, but with much apprehension. I think it's a given that we will all experience sx's, but how mild or severe is the question, this is where the fear comes in. Good luck to you also. I'm sure we will be keeping each other posted on our progress.
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