>>BOSTON, Oct. 29 /PRNewswire-FirstCall/ -- InterMune, Inc. (Nasdaq: ITMN - News) announced the presentation of positive clinical data from an investigator sponsored trial using Infergen® (interferon alfacon-1), the company's bio-optimized type 1 interferon alpha, in combination with ribavirin for the treatment of patients suffering from hepatitis C who have failed to respond to other interferon and ribavirin combination treatments (nonresponders). In addition, in vitro data were presented that showed potent synergistic antiviral effects of using Infergen and Actimmune® (interferon gamma-1b) in an in vitro model predictive of antiviral activity against hepatitis C virus (HCV).
Stephan Kaiser M.D., Head of the Liver Outpatient Department and Lecturer in Hepatology at the University of Tuebingen, Germany, presented the clinical study entitled: "Retreatment of standard interferon/ribavirin nonresponder patients with chronic hepatitis C with daily consensus interferon and ribavirin yields high sustained response rates." The study evaluated the efficacy of two induction dosing regimens of Infergen therapy followed by Infergen plus ribavirin combination therapy in 120 hepatitis C patients who had not responded to standard interferon plus ribavirin combination therapy. At time of enrollment, all patients had detectable levels of hepatitis C virus in their blood and the majority was infected with genotype 1, the most refractory form of the virus. Additionally, all patients showed biochemical evidence of liver damage and chronic liver inflammation. This was confirmed through liver biopsy and pathological examination.
"Approximately 50 percent of patients treated for hepatitis C virus do not respond to currently available treatments. This represents a significant and rapidly growing unmet medical need," said James E. Pennington, M.D., Executive Vice President of Medical and Scientific Affairs at InterMune. "Numerous published studies have shown that retreating hepatitis C nonresponders with pegylated interferon alpha plus ribavirin achieves very low sustained viral response rates in the 6 percent to 12 percent range. Dr Kaiser's presentation provides evidence for an approximately 3-fold higher sustained response rate measured 24 weeks after the end of treatment in the difficult to treat nonresponder population. Based on the data for daily use of Infergen plus ribavirin for HCV nonresponders, we plan to initiate a registration trial investigating the use of this combination therapy for the treatment of these patients."
This randomized, open-label, single center, parallel-group trial led by Dr. Kaiser evaluated patients treated with either 18 micrograms of Infergen for 4 weeks, followed by 9 micrograms for 8 weeks (18/9 microgram arm) or 27 micrograms of Infergen for 4 weeks, followed by 18 micrograms for 8 weeks (27/18 microgram arm). Thereafter, treatment was continued with 9 micrograms of Infergen in all treatment groups with ribavirin added at 10 - 15 milligrams per kilogram per day for the remaining 36 weeks. In the intent to treat analysis, those patients reaching end-of-treatment and 24-week follow-up showed sustained viral response rates of 43% and 37% for the 27/18 micrograms and 18/9 microgram arms, respectively. Viral levels were measured using a polymerase chain-reaction based assay. Due to adverse events, the Infergen dose had to be reduced in 16 percent of patients and discontinued in 7 percent of patients. The most common cause of adverse events was a reduction in white blood cell and platelet counts, especially in the 27 microgram Infergen dose group. These discontinuation rates and rates of serious adverse events are consistent with standard combination therapy.
Infergen and Actimmune In Vitro Evaluation
In another session, Lawrence Blatt, Ph.D., Vice President, Applied Research at InterMune, presented a study entitled: "Synergistic Effects of Type 1 (Infergen) and Type 2 (Actimmune) Interferons in preclinical models of HCV: Demonstration of potential efficacy." Scientists at InterMune and collaborators at Utah State University and Indiana University conducted this study. The researchers evaluated the antiviral effect of a combination of consensus interferon (Infergen) and interferon gamma-1b (Actimmune) in in vitro models of hepatitis C infection. This study was recognized as an AASLD Presidential Poster of Distinction.
The clinical success of combination therapy using interferon-alpha plus ribavirin is believed to be due, in part, to the direct effect of the interferon-alpha combined with the ability of ribavirin to induce an immune cell response mediated by the release of molecules such as interferon gamma. Based upon this hypothesis, InterMune scientists and their collaborators employed in vitro models of HCV replication to analyze the possible synergistic antiviral properties of Infergen in combination with InterMune's proprietary recombinant form of interferon gamma-1b (Actimmune).
Studies of the direct antiviral effects of Infergen and Actimmune in these in vitro models of HCV replication, such as an infectious flavivirus system (West Nile Virus), demonstrated very strong synergistic effects for a range of varying doses of combination therapy versus Infergen monotherapy. Analysis of gene expression showed that several genes involved in critical cellular processes that were not significantly upregulated by either drug alone were upregulated by the combination of Infergen and Actimmune. In addition, several known interferon stimulated genes were more significantly activated by the combination therapy versus Infergen monotherapy.
"There is a strong scientific rationale for the use of Infergen and Actimmune in combination for the treatment of hepatitis C," said Dr. Blatt. "These results provide intriguing evidence for a potentially synergistic antiviral effect and based upon this encouraging data, we are now evaluating a clinical program of this combination in HCV nonresponders."
About Chronic Hepatitis C
Over four million individuals in the United States have been exposed to the hepatitis C virus. The prevalence of chronic hepatitis C, a serious disease, is increasing. More than 200,000 patients in the United States are treated annually for hepatitis C infection.
About Infergen® (interferon alfacon-1)
Infergen® is a bio-optimized type 1 interferon alpha indicated for treatment of adult patients with chronic HCV infections. Infergen® is the only interferon alpha with data in the label regarding use in patients following relapse or non-response to treatment with certain previous treatments. The most common side effects are flu-like symptoms (i.e., headache, fatigue, fever, myalgia and rigors). Physicians and patients can obtain additional prescribing information regarding Infergen®, including the product's safety profile, which includes the black box warning for all interferon alphas regarding psychiatric, autoimmune, ischemic and infectious disorders, by visiting www.infergen.com.
About Actimmune® (interferon gamma-1b)
Interferon gamma is a naturally occurring protein that stimulates the immune system. InterMune markets Actimmune® for the treatment of two life-threatening congenital diseases: chronic granulomatous disease and severe, malignant osteopetrosis. The most commons side effects are flu-like symptoms, including fever, headache and chills. InterMune is currently initiating a pivotal Phase III trial to evaluate the safety and efficacy of interferon gamma-1b in patients with mild to moderate idiopathic pulmonary fibrosis (IPF). In addition the company is conducting a Phase III study of interferon gamma-1b in ovarian cancer and a Phase II study of interferon gamma-1b for the treatment of severe liver fibrosis, or cirrhosis, caused by hepatitis C virus (HCV). Physicians and patients can obtain additional prescribing information regarding Actimmune, including the product's safety profile, by visiting www.actimmune.com.<<
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