Press Release: Vion Pharmaceuticals Extends Agreement With SAFC Pharma Partnership for Cloretazine API Manufacturing

Vion Pharmaceuticals Extends Agreement With SAFC Pharma Partnership for Cloretazine API Manufacturing ST. LOUIS, March 21 -- SAFC, a member of the Sigma-Aldrich Group, continues its appointment as a high-potency active pharmaceutical ingredient (API) manufacturing partner for Vion Pharmaceuticals' Cloretazine® anti-cancer drug, presently in a Phase III clinical trial in combination with Ara-C for relapsed acute myelogenous leukemia (AML), and a Phase II pivotal trial for elderly de novo poor-risk AML. The amended contract extends the original 2003 supply agreement to 2009. Production for Vion's lead anticancer agent Cloretazine® (VNP40101M) API will continue to be provided by SAFC Pharma's flagship high-potency manufacturing facility in Madison, Wisconsin. Vion Pharmaceuticals, Inc. is committed to extending the lives and improving the quality of life of cancer patients worldwide by developing and commercializing innovative cancer therapeutics. The company has two small molecule products under evaluation in clinical trials -- Cloretazine® (VNP40101M), a novel alkylating agent, and Triapine®, a ribonucleotide reductase inhibitor. Vion also has the hypoxia-selective anti-cancer agent VNP40541 in late stage pre-clinical development. SAFC President Frank Wicks commented, "Vion Pharmaceuticals' decision to extend its involvement with SAFC Pharma for Cloretazine® API is a tribute to the consistency of high performance manufacturing at our Madison facility. The continuation of this appointment highlights our strengths as a premiere provider of process development and the production of complex, multi-step synthesis for highly potent and cytotoxic APIs." Driven by an increased demand for high potency compound manufacturing services, SAFC Madison recently marked the completion of its $12 million, 38,000 sq. ft. expansion. Its new on-site solid state chemistry research laboratory is expected to become operational in the spring of 2007. About SAFC: SAFC is the custom manufacturing group within the Sigma-Aldrich Group that focuses on both biochemical production and the manufacturing of complex, multi-step organic synthesis of APIs and key intermediates. SAFC has manufacturing facilities around the world dedicated to providing manufacturing services for companies requiring a reliable partner to produce their custom manufactured materials. SAFC has four operating segments -- SAFC Pharma, SAFC Supply Solutions, SAFC Biosciences, and SAFC Hitech -- and had annual sales of nearly $500 million in 2006. SAFC is one of the world's 10 largest fine chemical businesses. About Sigma-Aldrich: Sigma-Aldrich is a leading Life Science and High Technology company. Its biochemical and organic chemical products and kits are used in scientific and genomic research, biotechnology, pharmaceutical development, the diagnosis of disease and as key components in pharmaceutical and other high technology manufacturing. The Company has customers in life science companies, university and government institutions, hospitals, and in industry. Over one million scientists and technologists use its products. Sigma-Aldrich operates in 36 countries and has 7,500 employees providing excellent service worldwide. Sigma-Aldrich is committed to Accelerating Customer Success through Leadership in Life Science, High Technology and Service. For more information about Sigma-Aldrich, please visit its award-winning Web site at Cautionary Statement: This release contains forward-looking statements relating to future performance, goals, strategic actions and initiatives and similar intentions and beliefs and other statements regarding the Company's expectations, goals, beliefs, intentions and the like, which involve assumptions regarding the Company's operations and conditions in the markets the Company serves. The Company does not undertake any obligation to update these forward-looking statements.