Tibotec presents interim findings for TMC435, investigational hepatitis C treatment

New clinical data show antiviral activity of TMC435, an investigational protease inhibitor (PI) being developed by Tibotec BVBA for the treatment of chronic hepatitis C virus (HCV) infection.

Tibotec will present findings from three TMC435 studies, including a late-breaker poster on the proof-of-principle phase IIa trial, OPERA-1 (TMC435-C201), at the American Association for the Study of Liver Disease's (AASLD) Liver Meeting 2008 in San Francisco.

The current standard of care treatment for HCV infection, pegylated interferon (Peg-IFN) combined with ribavirin (RBV), is effective in 30 to 50 percent of patients infected with chronic genotype 1 HCV infection, the most common type in the United States. The development of new therapies and strategies for treating HCV, particularly the introduction of direct antivirals, may offer patients a new option with shorter treatment duration.

In interim findings from the first 28 days of treatment for the first cohort of fifty (50) treatment naïve HCV+, genotype 1, patients (once daily dose of 25 mg or 75 mg TMC435 versus placebo), both doses showed dose-dependent antiviral activity. TMC435 was administered in combination with PegIFNá-2a/RBV (triple therapy) for 28 days or as monotherapy for seven days and, thereafter, in combination with PegIFNá-2a/RBV (triple therapy) for three weeks. There were neither serious adverse events, nor grade 3 or 4 adverse events, related to TMC435 or any safety-related treatment discontinuations during this 28 day treatment period.

The most common adverse events associated with TMC435 were nausea, diarrhea, and headache. There were no clinically relevant changes in laboratory parameters, ECGs, or vital signs. Steady-state plasma trough levels of TMC435 25 mg and 75 mg represented ~10 and >30-fold excess above the HCV replicon EC50 value, respectively.

Mean reductions of HCV RNA from baseline to day seven with TMC435 alone and in triple therapy were 2.63 and 3.47 log10 IU/mL, respectively, in the 25 mg arm, and 3.43 and 4.55 log10 IU/mL in the 75 mg arm. In the 75 mg four-week triple therapy arm, no viral breakthrough was observed; 9/9 patients achieved HCV RNA below lower limit of quantification (<25 IU/mL) and 8/9 patients achieved undetectable HCV RNA (<10 IU/mL) at day 28 (RVR=89 percent).

"These data provide important information about an emerging new approach to treating HCV," said Professor and Chairman Michael Manns, Hannover Medical School, Germany. "The discovery and development of new treatments is critical to improving the standard of care for the millions of people living with this disease."

As a global virology leader committed to patient care, Tibotec uses innovative science and expertise to research, develop, and manufacture, drugs for medical conditions with an unmet need. The company has successfully launched two antiviral medications for the treatment of HIV and is now building a portfolio of novel antiviral therapies for HCV with the goal of becoming a prominent leader in the treatment of this infectious disease.

TMC435 was discovered through a drug discovery collaboration between Medivir and Tibotec. Tibotec has the right to develop and commercialize the compound throughout the world, excluding the Nordic countries. In addition to TMC435, Tibotec has another PI in phase III development for the treatment of chronic HCV infection.

"Tibotec is committed to evaluating the safety and efficacy of TMC435 in clinical studies to determine its potential use in people with HCV," said Roger Pomerantz, M.D., president of Tibotec Research and Development. "This is an important step in our mission of addressing treatment challenges of infectious diseases, including HCV, HIV and tuberculosis."

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