New data from Santaris Pharma miravirsen Phase 2a trial on HCV

Santaris Pharma A/S, a clinical-stage biopharmaceutical company focused on the discovery and development of RNA-targeted therapies, presents new data from the Phase 2a trial showing that miravirsen given as a four-week monotherapy treatment provided robust dose-dependent anti-viral activity with a mean reduction of 2 to 3 logs from baseline in HCV RNA (log10 IU/mL) that was maintained for more than four weeks beyond the end of therapy. These new clinical data as well as the data in the abstract are being presented in a late-breaking oral presentation on November 7 at 4p.m., at The Liver Meeting® 2011, the 62nd annual meeting of the AASLD, in San Francisco, California.

New clinical data from the Phase 2a study demonstrate that four out of nine patients treated at the highest dose (7 mg/kg) with miravirsen became HCV RNA undetectable with just four weeks of dosing. These data provide clinical evidence that miravirsen's unique mechanism-of-action offers high barrier to viral resistance and the potential for cure with monotherapy. Miravirsen was also well tolerated in patients with HCV, signaling a possible advantage over standard of care treatment.

"The miravirsen Phase 2a data is very promising considering that with only four weeks of treatment, miravirsen provided robust antiviral activity and throughout the study there was no sign of viral resistance," said Harry Janssen, M.D. Ph.D., Head of Liver Unit at the Erasmus MC University Hospital Rotterdam, The Netherlands and Lead Clinical Investigator of the study, who is presenting the data at AASLD. "These data, taken together with the observation that four patients became HCV RNA undetectable at the highest dose, show that longer duration of miravirsen monotherapy has the potential to produce sustained virological responses."

Data from the Phase 2a study show that the mean change from baseline in HCV RNA (log10 IU/mL) at 10 weeks after initiation of therapy was -0.57, -2.16, -2.73 in the 3, 5 and 7 mg/kg miravirsen dose groups, respectively vs. -0.01 in the placebo group.

"Due to its unique mechanism of action in targeting miR-122, miravirsen has the potential to change the way Hepatitis C is treated," said Stefan Zeuzem, M.D., Professor of Medicine and Chief of the Department of Medicine at the JW Goethe University Hospital, Frankfurt, Germany and Lead Clinical Investigator of the trial. "Miravirsen has the potential to be used as the central backbone treatment in combination with direct acting anti-viral agents as part of an interferon-free, infrequent dosing regimen."

"We are excited to show that miravirsen, the first microRNA-targeted drug to be given to patients, provides long-lasting suppression of HCV RNA, has a high barrier to viral resistance and a favorable tolerability profile," said Michael R. Hodges, MD, Vice President and Chief Medical Officer at Santaris Pharma A/S. "Miravirsen has a low propensity for drug interactions, and is ideally placed to be used in combination with direct acting anti-viral agents to limit the selection of resistant variants, prevent viral break through, and improve overall cure rates in patients with all types of HCV genotypes."

The randomized, double-blind, placebo-controlled, ascending multiple-dose Phase 2a study assessed the safety and tolerability of miravirsen in treatment-naive patients with chronic HCV genotype 1 infection. Patients with chronic HCV genotype 1 infection were enrolled sequentially to one of three cohorts (9 active: 3 placebo per cohort) at doses of 3, 5 and 7 mg/kg. Miravirsen was given as a total of 5 weekly subcutaneous injections over 29 days.

Developed using Santaris Pharma A/S proprietary Locked Nucleic Acid (LNA) Drug Platform, miravirsen is an inhibitor of miR-122, a liver specific microRNA critical for Hepatitis C virus RNA accumulation in the liver. Miravirsen is designed to recognize and sequester miR-122, making it unavailable to the Hepatitis C virus. As a result, the level of Hepatitis C virus is profoundly reduced.