Sanofi-aventis and Dyax Corp. announced today that they have entered into agreements in which sanofi-aventis has been granted an exclusive worldwide license for the development and commercialization of its fully human monoclonal antibody DX-2240

PARIS, France | February 12, 2008 | Sanofi-aventis (EURONEXT: SAN; NYSE: SNY) and Dyax Corp. (Nasdaq: DYAX) announced today that they have entered into agreements in which sanofi-aventis has been granted an exclusive worldwide license for the development and commercialization of its fully human monoclonal antibody DX-2240, aswell as a worldwide non exclusive license to Dyax’s proprietary antibody phage display technology.

Under the terms of the two agreements, Dyax could receive up to $500 million in license fees andmilestone payments, in the case of full commercial success of the first 5 antibody candidates, including DX-2240 for which $25 million are due in 2008. In addition, Dyax will receive royalties on net sales on antibodycandidates.

For all eligible future antibody product candidates, including DX-2240, sanofi-aventis will be responsible forthe development, registration, and commercialization and will book the sales worldwide. For certainantibody product candidates discovered by sanofi-aventis, Dyax will retain co-development and profitsharing rights, while sanofi-aventis will maintain the leadership in development, marketing and theconsolidation of sales.

DX-2240 is a fully human monoclonal antibody that targets the Tie-1 receptor on tumor blood vessels andhas therapeutic potential in numerous oncology indications. In preclinical animal models, DX-2240 has demonstrated activity against a broad range of solid tumor types. The antibody works by altering tumor vascular morphology, thereby increasing hypoxia and necrosis. In addition, DX-2240 in vivo increases theanti-tumor activity of other cancer therapies such as VEGF pathway inhibitors and other chemotherapeutic agents when used in combination.

Moreover, Dyax’s state-of-the-art antibody, peptide, and protein proprietary phage display libraries will givesanofi-aventis the opportunity to identify novel, high quality antibody products candidates with the potential to be moved rapidly into development.

About Dyax

Dyax is focused on advancing novel biotherapeutics for unmet medical needs, with an emphasis ononcology and inflammatory indications. Dyax utilizes its proprietary drug discovery technology to identifyantibody, small protein and peptide compounds for clinical development.Dyax is headquartered in Cambridge, Massachusetts, and has antibody discovery facilities in Liege,Belgium.

About Sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company, discovers, develops and distributes therapeutic solutions to improve the lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

SOURCE: SANOFI-AVENTIS