BARCELONA, April 19, 2012 /PRNewswire/ - Today Merck announced results demonstrating no difference in the rates of viral clearance between two anemia management strategies for patients with chronic hepatitis C virus (HVC) genotype 1 infection treated with VICTRELIS™ (boceprevir) in combination with peginterferon alfa-2b and ribavirin (P/R). Anemia is a common development of P/R therapy for chronic hepatitis C patients. For the patients studied, the anemia was either managed by ribavirin dose reduction or with the addition of erythropoietin (EPO), a drug that stimulates the bone marrow to produce red blood cells.
"The results are good news for treating physicians and patients as they show that reducing the dose of ribavirin is just as effective for the treatment of anemia as adding EPO, meaning there is no need for patients to take an additional drug," said Dr. Samuel Lee, hepatologist, Professor of Medicine at the University of Calgary and Canadian study investigator and author. "The new boceprevir combination therapy is a major advance in our ability to cure hepatitis C. We're pleased to note that our study confirmed that the rates of viral clearance were just above seventy percent."
The rates of sustained virologic response (SVR*) were 71 percent for both those patients whose anemia was managed by ribavirin dose reduction (178/249) and those patients whose anemia was managed by the addition of erythropoietin (EPO) (178/251). The rates of relapse were identical at 10 percent in both groups. These results from a Phase III, open-label study are being presented at The International Liver Congress™/47th European Association for the Study of the Liver (EASL) annual meeting in Barcelona, Spain.
Boceprevir in Canada
Boceprevir was approved for use in Canada in July 2011 for the treatment of chronic hepatitis C genotype 1 infection, in combination with peginterferon alpha and ribavirin, in adult patients (18 years of age and older) with compensated liver disease, including cirrhosis, who are previously untreated or who have failed previous therapy.
Hepatitis C in Canada
An estimated 250,000 individuals in Canada are infected with HCV and there are 3,200 to 5,000 newly infected individuals each year.1 HCV damages the liver and may lead to serious complications, including death, when left untreated.2 It is the leading cause of liver transplants in Canada.3
About the Study
In this study, 687 treatment-naïve adult patients with chronic HCV genotype 1 who had baseline hemoglobin levels of less than or equal to 15 g/dL were enrolled in a multinational, open-label trial and monitored for the development of anemia. Patients were treated with a 4-week lead-in of peginterferon alfa-2b (1.5 mcg/kg/week) and an investigational dose of ribavirin (600-1,400 mg/day), followed by the addition of boceprevir (800 mg three times a day) after week 4 for 24 or 44 weeks based on HCV-RNA levels at treatment week 8. Sixteen (16) percent (111/687) of patients were enrolled in Cohort 1 and assigned a fixed-dose regimen that included the 4-week lead-in of P/R followed by the addition of boceprevir for 44 weeks. A protocol amendment was then added to allow the use of the response-guided therapy (RGT) paradigm, consistent with findings in the pivotal clinical studies for boceprevir, and the rest of the patients were enrolled in Cohort 2.
The results for patients receiving the fixed-dose regimen (Cohort 1) versus the RGT paradigm (Cohort 2) did not differ and have been combined in the presentation of these data. Patients with a less than 2-log10 decline in HCV-RNA at week 12, or a greater than or equal to lower limit of quantification of HCV-RNA at week 24 were considered treatment failures and were discontinued from the studies.
A total of 500 patients developed anemia, defined by having hemoglobin of less than or equal to 10 g/dL (or less than 11 g/dL and were expected to reach less than or equal to 10 g/dL before the next visit).
These patients were randomized to receive either ribavirin dose reduction (by 200 to 400 mg/d) or the addition of EPO (40,000 IU/week). A secondary method of anemia management, such as the addition of EPO, ribavirin dose reduction or transfusion, was later permitted if a patient's hemoglobin reached less than or equal to 8.5 g/dL. Treatment was discontinued if hemoglobin levels reached less than or equal to 7.5 g/dL. If the initial hemoglobin measurement qualifying a patient as anemic was less than or equal to 8.5 g/dL, that patient was not randomized to one of the anemia management strategies.
The primary endpoint of the study was the comparison of SVR in patients who were randomized to receive ribavirin dose reduction or the addition of EPO.
Merck's global commitment to advancing hepatitis therapy
Merck is committed to building on its strong legacy in the field of viral hepatitis by continuing to discover, develop and deliver vaccines and medicines to help prevent and treat viral hepatitis. In hepatitis C, company researchers developed the first approved therapy for chronic HCV in 1991 and the first combination therapy in 1998. In addition to ongoing studies with VICTRELIS, extensive research efforts are underway to develop additional innovative oral therapies for viral hepatitis treatment.
Today's Merck is a global health care leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our medicines, vaccines, biologic therapies, and consumer and animal products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to health care through far-reaching policies, programs and partnerships. For more information about our operations in Canada, visit www.merck.ca.
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*SVR, the protocol specified primary efficacy endpoint of the study, is defined as achievement of undetectable HCV-RNA at 24 weeks after the end of treatment in all randomized patients treated with any study medication. Per protocol, if a patient did not have a 24-week post-treatment assessment, the patient's 12-week post-treatment assessment was utilized.
1 Canadian Institutes of Health Research. About the Hep C Research Initiative. http://www.cihr-irsc.gc.ca/e/38855.html. Accessed April 13, 2012.
2 Public Health Agency of Canada. http://www.phac-aspc.gc.ca/hepc/pubs/multiling-hepc/index-eng.php. Accessed April 13, 2012.
3 Canadian Liver Foundation. http://www.liver.ca/Liver_Disease/. Accessed April 13, 2012.