FDA’s Oncologic Drugs Advisory Committee (ODAC) Votes To Not Support Benefit/Risk Profile Of DACOGEN® (decitabine) In Acute Myeloid Leukemia

Astex Pharmaceuticals, Inc. (NASDAQ:ASTX) today announced that the U.S. Food and Drug Administration’s (FDA’s) Oncologic Drugs Advisory Committee (ODAC) voted 10 to 3 with one person abstaining that data in our partner Eisai’s supplemental new Drug Application (sNDA) for DACOGEN® (decitabine) for Injection did not support a favorable benefit-risk profile for the treatment of acute myeloid leukemia (AML) in adults 65 years of age or older who are not considered candidates for induction therapy.

The FDA has the option of seeking the advice of its advisory committees when it is reviewing a new drug application, although it is not obliged to follow the committee’s recommendation. The PDUFA date is March 6, 2012.

The advisory committee reviewed data from Eisai’s supplemental New Drug Application (sNDA) which was accepted for FDA review in July 2011. The application is based on the open-label Phase III clinical trial (DACO-016) data presented at the 2011 Annual Meeting of the American Society of Clinical Oncology (ASCO).

About DACOGEN

Dacogen is currently approved for the treatment of MDS in about 30 countries. Dacogen is licensed to Eisai Co., Ltd and Eisai has licensed rights outside of North America to Janssen-Cilag International NV and other affiliates of Cilag GmbH International. Astex receives royalties on global sales of Dacogen.

DACOGEN is approved, in the United States, for treatment of patients with myelodysplastic syndromes (MDS), including previously treated and untreated, de novo and secondary MDS of all French-American-British (FAB) subtypes (refractory anemia, refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, chronic myelomonocytic leukemia), and Intermediate-1, Intermediate-2 and High-Risk International Prognostic Scoring System (IPSS) groups.

Important Safety Information

Treatment with DACOGEN is associated with neutropenia and thrombocytopenia. Complete blood and platelet counts should be performed as needed to monitor response and toxicity but at a minimum prior to each dosing cycle. After administration of the recommended dosage for the first cycle, treatment for subsequent cycles should be adjusted if indicated by dose adjustment guidelines. Clinicians should consider the need for early institution of growth factors and/or antimicrobial agents for the prevention or treatment of infections in patients with MDS.