SciClone Presents New Preclinical Data Highlighting Potential Role of SCV-07 in Cancer Treatment at 2011 ASCO Annual

FOSTER CITY, CA, Jun 04 (MARKET WIRE) --
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(R)
(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(R), the most widely prescribed
broad-spectrum anti-convulsant in China; Tritace, an ACE inhibitor for
the treatment of hypertension; Stilnox(R), a fast-acting hypnotic for the
short-term treatment of insomnia (marketed as Ambien(R) in the US); and
Aggrastat(R), 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.

Corporate Contacts

Gary Titus
Chief Financial Officer
650.358.3456
gtitus@sciclone.com

Ana Kapor
Investors/Media
650.350.4825
akapor@sciclone.com

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