SciClone Pharmaceuticals, Inc. Hepatitis C Drug Fails Main Goal
The thymalfasin treatment group did not achieve statistical significance for the primary endpoint of sustained virological response (SVR) as assessed in the primary analysis population, i.e., the intent-to-treat (ITT) population. In the prospectively defined secondary population of patients who completed the full course of 48 weeks of treatment with thymalfasin in addition to peg-IFN-2a and RBV (Completer Population), the primary endpoint achieved statistical significance.
"We are disappointed that the study did not reach its primary efficacy endpoint in the ITT population. Nevertheless, the data seen in the Completer Population suggest a potential benefit of using thymalfasin in patients who completed the full course of treatment," said Friedhelm Blobel, Ph.D., President and Chief Executive Officer of SciClone Pharmaceuticals, Inc. "We plan to analyze the data further in coming weeks and will present the full results at an upcoming clinical conference."
In the ITT population (552 patients), 12.73% of the patients in the thymalfasin treated group achieved an SVR at week 72 of the trial, versus 10.47% in the control group (p=0.407). In the Completer Population (182 patients), the difference in SVR between the thymalfasin treated group and the control group achieved statistical significance (p=0.048).
"These data suggest that the immunomodulatory activity of thymalfasin may play an important role in maintaining the viral response in patients who completed the full prescribed 48 weeks of treatment," said Israel Rios, MD, Chief Medical Officer of SciClone. "Although the safety analyses are still ongoing, thymalfasin appeared to be well tolerated. During the course of the trial the side effects reported were those usually associated with the use of interferon and ribavirin."
About Thymalfasin Triple Therapy for HCV
This phase 3, multi-center, double-blinded, randomized study enrolled 552 predominately genotype 1 HCV patients who had not responded to previous treatment with pegylated interferon alpha and ribavirin. Patients were randomized, in a one-to-one ratio, to receive either thymalfasin or a placebo, and all patients received pegylated interferon alpha-2a and ribavirin. The study was designed to continue the treatment up to 48 weeks only in patients who were HCV RNA negative after 24 weeks of treatment. After completing 48 weeks of treatment, patients were monitored twice during a 24-week observation period at week 60 and week 72.
About Thymalfasin
Thymalfasin, also referred to as thymosin alpha 1, is a synthetic preparation of a thymic peptide which circulates in the blood naturally, and is instrumental in the immune response to certain cancers and viral infections. Published studies have shown that thymalfasin helps stimulate and direct the body's immune response to eradicate infectious diseases like HCV and HBV, as well as certain cancers. Thymalfasin appears to be well tolerated with few reports of significant side effects or toxicities associated with its use. Thymalfasin elicits a variety of immune system responses against viruses.
One such response is an increase in production of certain subsets of white blood cells and their differentiation into CD-4 helper-cells, specifically towards differentiation into the Th1 subset of CD-4 helper cells (Th1 cells secrete cytokines such as interleukin-2 (IL-2) and gamma interferon that can help the immune response). Moreover, as thymalfasin increases differentiation into Th1 cells, it also results in decreased CD-4 cell differentiation into the Th2 subset of CD-4 helper cells that produce cytokines, such as IL-4, which are associated with persistence of viral infection. In addition, thymalfasin stimulates several other components of the immune response that help the body attack and kill virally-infected cells.
ZADAXIN®, SciClone's brand of thymalfasin, is currently approved in more than 30 countries worldwide to treat a variety of indications. In clinical studies, more than 4,000 patients with viral hepatitis B and C, primary immunodeficiency diseases, and numerous cancers have been treated with thymalfasin.
In June 2007, SciClone and Sigma-Tau announced that a phase 2 clinical trial of thymalfasin treating patients with stage IV malignant melanoma had met its primary endpoint, increased tumor response and also showed benefits in extending overall survival as well as progression free survival.
About Hepatitis C Virus
HCV is a blood-borne viral disease which causes inflammation of the liver. The World Health Organization estimates that 170 million people worldwide are infected with HCV, and the Centers for Disease Control estimates that approximately 8 to 10 million people are infected with HCV throughout the U.S. and Europe. Of these patients, approximately 85% are chronically infected, and the persistent liver inflammation in chronically infected patients can develop serious complications including cirrhosis of the liver, liver failure, and hepatocellular carcinoma or liver cancer. Only about half of all naive patients treated with current therapy achieve an SVR, and SciClone estimates nearly 1 million HCV patients in the United States alone have failed or will fail current therapy. The markets for HCV therapeutics in the three major economic regions of the United States, Europe and Japan are estimated to total approximately $3 billion currently and are expected to grow to approximately $10 billion by 2014.
About SciClone
SciClone Pharmaceuticals (NasdaqGM:SCLN - News) is a global biopharmaceutical company dedicated to developing and commercializing promising therapies for life-threatening diseases. SciClone's corporate infrastructure leverages diverse global resources to finance growth in multiple markets and fund development of its advanced pipeline of mid- to late-stage product candidates. SciClone's lead product, ZADAXIN®, is approved for sale in over 30 countries for the treatment of hepatitis B, hepatitis C, and certain immune-sensitive cancers. Sales of ZADAXIN grew by 14% in 2007, reaching $34 million in China alone. SciClone has several products in clinical development, consisting of thymalfasin for stage IV melanoma, RP101 for the treatment of pancreatic cancer, and SCV-07 for the treatment of HCV and oral mucositis; and, awaiting approval in China, DC Bead(TM), for the treatment of liver cancer. For additional information, please visit www.sciclone.com.
The information in this press release contains forward-looking statements including our expectations and beliefs regarding future sales and financial results for 2008 and the timing and results of our clinical trials. You are urged to consider statements that include the words "may," "will," "would," "could," "should," "might," "believes," "estimates," "projects," "potential," "expects," "plans," "anticipates," "intends," "continues," "forecast," "designed," "goal," or the negative of those words or other comparable words to be uncertain and forward-looking. These statements are subject to risks and uncertainties that are difficult to predict and actual outcomes may differ materially. These risks and uncertainties include our forward-looking statements because of the inherent uncertainties, including in the timing of clinical trial events such as including patient enrollment, requirements of, and future actions of, the U.S. Food and Drug Administration, the fact that experimental data, and clinical results derived from studies with animals or a limited group of patients, and as well as comparisons with other clinical trials may not be predictive of the results of larger studies and, therefore, such experimental or clinical data are not necessarily predictive indicative of the efficacy or safety or the results of larger studies and clinical trials. Please also refer to the other risks and uncertainties described in SciClone's filings with the Securities and Exchange Commission. All forward-looking statements are based on information currently available to SciClone, and SciClone assumes no obligation to update any such forward-looking statements.
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Corporate Contact: Ana Kapor SciClone Pharmaceuticals, Inc. 650.358.3437
Source: SciClone Pharmaceuticals, Inc.