AMBION AND CENIX BIOSCIENCE PARTNER TO OFFER FIRST COMMERCIALLY-AVAILABLE HUMAN GENOME-WIDE siRNA LIBRARY

Austin, TX, and Dresden, Germany - March 24, 2003: Ambion, Inc., an established market leader in the supply of siRNA reagents for RNA-mediated interference (RNAi), and Cenix BioScience GmbH, a recognized pioneer in the high throughput application of RNAi for therapeutic drug discovery and development, today announced they have formed a partnership to co-develop and commercialize the first human genome-wide siRNA library. RNAi is a revolutionary new method of targeted gene silencing that is achieved in mammalian cells through the use of short interfering RNA molecules or siRNAs, and which was voted the top scientific breakthrough of 2002 by Science Magazine. RNAi technology is greatly accelerating the functional characterization of disease-relevant genes for drug discovery and basic research efforts. Genome-wide siRNA libraries represent the most powerful new tool for fulfilling the promise of the Human Genome Project and molecular medicine initiatives in all disease areas, by enabling the efficient and systematic identification of novel therapeutic genes.

The systematic genome-scale application of RNAi was originally pioneered by the founders of Cenix. Applying over four years of industry-leading expertise in this area, which started with lower eukaryotes, Cenix will now use its proprietary algorithms to design fully optimized siRNA reagents that will enable high-throughput (HT) genome-wide screening in human cells. Ambion, an established market leader in the development, production and distribution of RNA based research products, will manufacture these reagents and market them to its extensive international customer base. The two companies are committed to regularly updating the siRNA library in accordance with the evolution of human genome sequence annotations. The first products are expected to be on the market in the middle of 2003.

Dr. Christophe Echeverri, CEO and CSO of Cenix BioScience, commented on the relationship, “We expect the discovery of new drug targets via genome-wide RNAi screening in human cells to drive a very wide and fast-growing range of biomedical research for years to come. In view of Ambion’s robust R&D program, comprehensive line of top quality RNA research products and clear dedication to customer service, we are extremely pleased to have partnered with the industry’s premiere RNA specialist for this crucial project.”

Dr. Matt Winkler, CEO of Ambion said, "We are delighted to have partnered with Cenix on this exciting project. Cenix’s leading expertise in multi-organism genome-wide applications of RNAi offers the perfect synergies to allow Ambion to continue expanding its comprehensive range of quality RNAi products, including siRNA products, in this important direction."

The siRNA product family resulting from this partnership will include comprehensive libraries to cover the entire genome, the “druggable genome”, as well as more focused validated siRNA collections to target specific gene families, and specific genes. These products will therefore represent landmark additions to Ambion’s current industry-leading line of siRNA products.

Cenix BioScience GmbH is a pioneer and industry leader in the application of RNA-mediated interference (RNAi) for the discovery and development of new therapeutics. The genome-scale application of RNAi was originally pioneered by the scientific founders of Cenix (Nature, 2000: vol 408: 331). Cenix’s current in-house research programmes are focused on the development of the novel class of RNAi-based medicines for the treatment of cancer and viral diseases. In addition, Cenix is leveraging its expertise in the RNAi-based discovery and validation of novel drug targets through collaborative research with industry and academic partners.

The Company was founded in 1999 as a spin-out from the European Molecular Biology Laboratory (Heidelberg, Germany) and the Max Planck Institute of Molecular Cell Biology and Genetics (Dresden, Germany). For more information, please visit the company’s web site www.cenix.com.

Ambion, Inc., is a leader in the development and supply of innovative RNA-based life science research and molecular diagnostic products. Ambion has taken a leadership role in developing products for handling, preserving, isolating, detecting and measuring RNA in areas such as molecular biology, cell biology, microbiology, drug discovery and genomics. For more information, please visit the company’s web site www.ambion.com.

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Notes to Editors:

RNAi – A revolutionary gene silencing technology
RNA-mediated interference, or RNAi, is a powerful new approach for achieving targeted gene silencing of pathological genes using complementary double stranded RNA (dsRNA) as the triggering agent. Discovered in 1998, this technology has been shown to work in a wide range of experimental models from plants to human cells and was voted the top scientific breakthrough of 2002 by Science Magazine. RNAi is a naturally occurring defense mechanism against molecular parasites. The pathway mounts a powerful cellular response to the presence of dsRNA molecules, usually rare in organisms and therefore recognized as “foreign”. These molecules, through their sequence, direct the cell’s RNAi machinery to specifically degrade all complementary messenger RNAs in the cell, thereby silencing the expression of the corresponding genes. Thus, by introducing dsRNAs containing desired sequences into cells or organisms, the RNAi pathway can be harnessed to silence or “knock down” essentially any target gene of interest with tightly controlled specificity. When applied in vertebrate systems including human cells, the RNAi pathway is most readily triggered through the use of short interfering dsRNA molecules, or siRNAs. Used as a research tool and potential therapeutic, RNAi offers an unprecedented combination of:

• High potency
• Ideal specificity
• High scalability for large scale applications
• Wide cross species applicability
• Excellent experimental reproducibility

As a result, RNAi has rapidly become the new method of choice for a wide range of biomedical applications, in particular emerging as the best new functional genomics screening method to identify and validate new therapeutic drug targets. In so doing, RNAi is not only replacing conventional antisense and ribozyme-based paradigms for cell-based research, but now also offers the promise of a more time- and cost-efficient alternative to transgenic mouse knock-out strategies.