SciClone Pharmaceuticals, Inc announced promising results from its proof-of-concept phase-2 clinical trial using its proprietary, immunomodulatory compound SCV-07 as a sole agent administered to patients chronically infected with the hepatitis C virus (HCV).

The trial was designed to evaluate the effect of SCV-07 on hepatitis C viral load, as well as on other measures of immune response. SCV-07 demonstrated activity in some treated patients in the higher dosage groups, and the decrease in viral load in these patients was accompanied by an increase in an immunological biomarker which is usually correlated with response against HCV. Additionally, SCV-07 was shown to be generally safe and well-tolerated with no dose limiting toxicities or serious adverse events reported. "In this study, SCV-07 demonstrated encouraging antiviral activity in patients who were previous relapses to treatment," said Friedhelm Blobel, president and chief executive officer of SciClone.

"This is particularly exciting as patients were treated with only seven days of monotherapy. Based on the promising outcome of this trial, SciClone plans to investigate further SCV-07's potential to prime the human immune system against HCV and plans to discuss with the FDA the initiation of a follow-up phase 2B trial. The follow-up trial may also be used to determine whether SCV-07 is capable of replacing or improving the response to current standard of care treatment. We are also pleased by the lack of side effects seen during treatment with SCV-07."

This randomized, placebo-controlled trial enrolled 34 patients infected with the difficult to treat genotype 1 strain of HCV, who had previously responded to treatment with interferon alpha and ribavirin but subsequently relapsed. Patients were randomized into three cohorts of escalating doses, and received daily subcutaneous injections of SCV-07 or placebo. After completing seven days of therapy, all patients were monitored for a further seven days and patients in the highest dosage group were monitored for 30 days following end of treatment.

The primary objective of the trial was to assess the antiviral effect of SCV-07 on hepatitis C viral load and the pharmacodynamic effect as assessed by various biomarkers. In chronically infected patients, without treatment, variations in the amount of circulating HCV typically do not vary by more than 0.3 log. In this trial, reductions of greater than 0.6 log were seen in more than 10 per cent of treated patients.

"SCV-07 has been shown to bind to macrophages and inhibit STAT-3 dependent responses, leading to stimulation of the Th1 immune response," said Israel Rios, senior vice president and chief medical officer of SciClone. "A Th1 immune response is typically correlated with improved response in HCV patients. Additionally, neopterin levels are usually increased in connection with the stimulation of the Th1 immune response. In this trial, we have seen increased neopterin levels accompanying reduction in viral loads."

SciClone's proprietary drug candidate SCV-07 (gamma-D-glutamyl-L-tryptophan) is a synthetic peptide with proven immune stimulating effects. SCV-07 has shown efficacy in treating various viral and bacterial infections.

SciClone Pharmaceuticals is a biopharmaceutical company engaged in the development of therapeutics to treat life-threatening diseases.