SciClone Pharmaceuticals, Inc. Presents New Preclinical Data Highlighting Potential Role of SCV-07 in Cancer Treatment at 2011 American Society of Clinical Oncology Annual Meeting

FOSTER CITY, CA--(Marketwire - June 04, 2011) - SciClone Pharmaceuticals, Inc. (NASDAQ: SCLN) ("Company") today announced new data from preclinical studies of SCV-07, the Company's lead development product candidate, which showed that the compound successfully inhibited the growth of a variety of tumor cell lines in mice. These results suggest that the use of SCV-07 as a treatment for oral mucositis (OM) in patients with a variety of cancers should not interfere with the antitumor effects of primary cancer therapy, but may in fact enhance the tumor response of conventional therapy. Additionally, SciClone researchers have identified potential molecular and cellular mechanisms by which SCV-07 may be able to inhibit both mucositis and tumor progression. These data are being presented today in two poster presentations at the 2011 American Society of Clinical Oncology ("ASCO") Annual Meeting in Chicago.

In one study, researchers inoculated nude mice with various tumor cell lines and once tumors were established, randomized the mice to receive various doses of SCV-07 or the study's control vehicle. Tumors were then measured every two days and tumor volume and tumor growth were calculated using standard measurement tools. Study results showed that tumors in SCV-07-treated animals grew more slowly than those in the control group, with the reduction being generally dose dependent and statistically significant at higher doses. The tumor cell lines examined in this study included human head and neck cancer, human acute promyelocytic leukemia, human acute lymphoblastic leukemia, human melanoma, and murine T cell lymphoma. Results from these studies were presented today at the ASCO meeting in a poster titled "Anti-tumor activity of the immunomodulatory peptide gamma-D-glutamyl-L-tryptophan in leukemia, lymphoma, and head and neck cancer xenograft models."

"As we are currently developing SCV-07 as prevention for OM in patients with head and neck cancer, it is important that we establish that the compound will not interfere with the effectiveness of patients' primary cancer treatment. These study results suggest that SCV-07 may not negatively impact patient response to primary cancer treatment, and also suggest that SCV-07 may in fact enhance antitumor activity," said Cynthia Tuthill, PhD, Vice President and Chief Scientific Officer of SciClone. "These findings provide further support for SCV-07 as a potential treatment for OM and we look forward to continuing to make progress with our ongoing Phase 2b study of SCV-07 in this indication."

In a second study, researchers explored the molecular and cellular activities associated with SCV-07 treatment in various tumor cell lines, in order to understand more about the mechanism by which the compound triggers inhibition of OM and tumor progression. Findings showed that treatment with SCV-07 set in motion a series of molecular processes including activation of the protein tyrosine phosphatase SHP-2, inhibition of phosphorylation of STAT3, and changes in cytokine production. These molecular processes led to important shifts in key immune system components such as macrophages and T cells which ultimately produced the immune responses that may be responsible for inhibiting both OM and tumor progression. These findings offer important insight into the potential mechanisms of action for SCV-07 and support further investigation in this area. Results from this study were presented today at the ASCO meeting in a poster titled "Identification of signaling pathways involved in the mechanism of action of the immunomodulatory peptide gamma-D-glutamyl-L-tryptophan."

About Oral Mucositis
OM is a common, painful, debilitating complication of cancer treatment, and SciClone estimates that total medical costs reached around $4.2 billion in the U.S. and $10 billion worldwide in 2010. OM is a condition in which the sensitive cells lining the mouth and throat are damaged by cancer treatments such as chemotherapy (with or without radiation) and become painful mouth sores. Severe OM has been reported to occur in about 50% of patients who receive chemoradiation for the prevention of cancers of head and neck (Sonis, Core Evidence, 2009). Importantly, radiation to the head and neck, especially when it includes the tissues of the mouth, pharynx and hypopharynx, results in significant ulcerative OM in greater than 90% of patients (Manas et al, Clinical Translational Oncology, 2009) and can compromise the patient's ability or willingness to accept a complete course of therapy. Symptoms can include painful ulcers in the mouth and throat, redness and swelling of the gums, dryness and overall soreness in the mouth, and difficulty eating, swallowing, talking and drinking. In addition to the symptoms of OM and its impact on quality of life and continued therapy, mucositis can cause adverse effects on a variety of other health and economic outcomes, such as a risk of serious infection, the need for parenteral nutrition and narcotic analgesia, and increased hospitalization and feeding-tube placement. The National Cancer Institute estimates that 450,000 patients per year in the U.S. suffer from OM during cancer therapy.

About SCV-07
SCV-07 (gamma-D-glutamyl-L-tryptophan) is a small molecule that appears to stimulate the immune system through inhibition of STAT3 signaling and the resulting effects on T-helper 1 cells. SCV-07 has been shown to be efficacious in animal models of immune-sensitive diseases, including prevention of oral mucositis, treatment of cancer and viral infections, and enhancement of response to vaccines.

SCV-07 is protected by composition of matter patents as well as multiple method of treatment patents. SciClone has exclusive worldwide rights to SCV-07 outside of Russia, where the molecule has been approved for stimulation of depressed immune systems.

About SciClone's Phase 2b OM Study
SciClone initiated in January 2011 its phase 2b clinical trial of SCV-07 for the prevention of oral mucositis. The study is examining three doses of SCV-07, including two higher doses than those used in the company's phase 2a study, to assess the drug's impact on modifying the course of OM in patients with head and neck cancer. In addition, the trial is further evaluating SCV-07's safety and tolerability in this patient population, as well as the role played by specific genetic profiles on patient response to the treatment.

About SciClone
SciClone Pharmaceuticals is a revenue-generating, China-centric specialty pharmaceutical company with a substantial business and a product portfolio of novel therapies for cancer, infectious diseases and cardiovascular, urology and central nervous system disorders, and respiratory conditions. SciClone's ZADAXIN® (thymalfasin) is approved in over 30 countries for the treatment of hepatitis B (HBV), as a vaccine adjuvant, for the treatment of hepatitis C (HCV), and certain cancers. SciClone markets nearly 20 products in China besides ZADAXIN, including Depakine®, the most widely prescribed broad-spectrum anti-convulsant in China; Tritace, an ACE inhibitor for the treatment of hypertension; Stilnox®, a fast-acting hypnotic for the short-term treatment of insomnia (marketed as Ambien® in the US); and Aggrastat®, a recently-launched intervention[al] cardiology product. The Company also has a pipeline of China-focused assets awaiting regulatory approval in that country. On the global development side, SciClone is evaluating SCV-07 in a phase 2b trial to modify the course of oral mucositis in patients with head and neck cancer. SciClone is headquartered in Foster City, California. For additional information, please visit www.sciclone.com.

Forward-Looking Statements
The information in this press release contains forward-looking statements, including our expectations and beliefs regarding the timing potential benefit of SCV-07 based upon pre-clinical data. 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 the fact that experimental data, and pre-clinical results derived from studies with animals or a limited group of patients, 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 or 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.

Ambien, Depakine and Stilnox are registered trademarks of Sanofi-Aventis.

Aggrastat is a registered trademark of Merck & Co., Inc.