Ambit Biosciences and Astellas Announce Upcoming Presentation of AC220 Data at the 16th Annual Congress of the European Hematology Association

San Diego and Tokyo (ots/PRNewswire) -

Ambit Biosciences Corporation and Astellas Pharma Inc. today
announced that the first presentation of interim data from a global
multi-center Phase 2 study evaluating the investigational drug AC220,
a potent and selective FLT3 inhibitor. The data will be presented in
an oral session at the upcoming European Hematology Association (EHA)
meeting in London. The abstract (#1019) can be accessed at the EHA
Congress website at http://eha.eurocongres.com/16th/. Details of the
presentation are as follows:

Title: "A Phase II Open-Label, AC220 Monotherapy Efficacy (ACE)
Study in Patients with Acute Myeloid Leukemia (AML) With FLT3-ITD
Activating Mutations: Interim Results"

Date & Time: Sunday, June 12, 2011, from 9:00am to 9:15am GMT
(London)

Session Title: Acute Myeloid Leukemia - Clinical 2

Location: Hall S4, ExCeL London

Presenter: Mark Levis, MD, PhD, Associate Professor, Oncology and
Medicine, Division of Hematologic Malignancies, Johns Hopkins
(Baltimore, Maryland, USA)

About AC220

AC220 is being developed in collaboration between Ambit
Biosciences and Astellas Pharma Inc., and is a novel, potent, highly
selective, orally bioavailable FMS-like tyrosine kinase-3 (FLT3)
inhibitor. AC220 is currently under evaluation in a Phase 2 clinical
trial as mono-therapy treatment for adult and elderly patients with
relapsed/refractory AML that have an internal tandem duplication
(ITD) mutation in the FLT3 gene. AML is one of the most common types
of blood cancers in adults, with ITD mutations in the FLT3 gene
occurring in 25-30 percent of AML patients. FLT3 ITD mutations confer
poor prognosis, with early relapse and lower survival following
treatment with existing therapies, including chemotherapy and
hematopoietic stem cell transplant.

About AML

Acute myeloid leukemia is a form of blood cancer. According to
the American Cancer Society, approximately 13,000 adults were newly
diagnosed with AML in 2009 in the United States with approximately
9,000 expected to die of the disease in that year. AML is generally a
disease of older people and is uncommon before the age of 40. The
average age of a patient with AML is 67 and median survival for these
patients is less than six months. The five-year survival rate for all
AML patients is less than 15 percent. According to a report from
Decision Resources, the U.S. AML market is expected to more than
double by 2015.

About the Ambit/Astellas Collaboration

In December 2009, Ambit and Astellas entered into a global
strategic partnership agreement to jointly research, develop and
commercialize FLT3 kinase inhibitors in multiple indications,
including the lead investigational compound, AC220. The companies are
presently evaluating AC220 in a Phase 2 clinical trial in relapsed
and refractory AML patients that have the internal tandem duplication
(ITD) mutation in the FLT3 gene. The companies are also collaborating
on a comprehensive development program to explore the utility of
AC220 in other AML patient subpopulations. Additionally, the
companies are collaborating on a research and development program for
additional FLT3 inhibitors for a variety of oncology and non-oncology
indications. The companies share equal responsibility and expenses
for the development of products in the US and Europe, while Astellas
has sole responsibility in the rest of the world. Astellas will be
responsible for implementation of commercialization activities
worldwide. Ambit received a $40 million up-front payment upon
entering into the collaboration agreement, and is eligible to receive
up to $350 million in development milestone payments, undisclosed
sales milestones, and tiered, double-digit royalties on global
revenues. Ambit also has an option to co-promote products in the U.S.
where Astellas and Ambit share equally all profits and losses
generated from U.S. sales.

About Ambit Biosciences

Ambit Biosciences is a privately-held biopharmaceutical company
engaged in the discovery and development of small molecule kinase
inhibitors for the treatment of cancer, inflammatory disease, and
other indications. Ambit's lead compound, AC220, is a novel, potent,
highly selective, orally bioavailable FMS-like tyrosine kinase-3
(FLT3) inhibitor, and is currently under clinical investigation in
patients with relapsed or refractory AML. Ambit is developing AC220
in collaboration with Astellas Pharma Inc. as part of a worldwide
agreement to jointly develop and commercialize FLT3 kinase inhibitors
in oncology and non-oncology indications. In addition to AC220,
Ambit's clinical pipeline includes AC480, an oral pan-HER inhibitor,
and AC430, an oral JAK2 inhibitor. Ambit also has a pipeline of
preclinical candidates which includes CEP-32496, a BRAF inhibitor
licensed to Cephalon.

About Astellas

Astellas Pharma Inc., located in Tokyo, Japan, is a
pharmaceutical company dedicated to improving the health of people
around the world through provision of innovative and reliable
pharmaceuticals. Astellas has approximately 16,000 employees
worldwide. The organization is committed to becoming a global
category leader in Urology, Immunology & Infectious Diseases,
Oncology, Neuroscience, and DM complications & Metabolic Diseases.
For more information on Astellas Pharma Inc., please visit our
website at http://www.astellas.com/en.

ots Originaltext: Astellas Pharma
Im Internet recherchierbar: http://www.presseportal.de

Contact:
Contacts: Ambit Biosciences: Alan Fuhrman, Chief FinancialOfficer,
+1-858-334-2133; Doug Sherk/Jenifer Kirtland, EVC Group,+1-415-896-68
Media: Janine McCargo, EVC Group, +1-646-528-4034. AstellasPharma
Inc: Corporate Communications, +81-3-3244-3201 .