Richmond, California and Cranbury, New Jersey -- January 21, 2003 -- Sangamo BioSciences, Inc. (Nasdaq: SGMO) and Purdue Pharma L.P. announced today that the companies have signed an agreement that provides Purdue Pharma with Sangamo’s proprietary zinc finger DNA binding protein transcription factors (ZFP TFs) for use in its research and drug discovery program. The financial terms of the agreement were not disclosed. “We are pleased to be able to provide Purdue Pharma, a company known for its research on chronic pain, with ZFP TFs for their drug discovery and development work,” said Edward Lanphier, Sangamo’s president and chief executive officer. “It is gratifying to be able to count one of the world's fastest growing pharmaceutical companies among those utilizing Sangamo’s ZFP technology. “We believe that Sangamo’s ZFP TF technology will enable us to specifically regulate the expression of therapeutically relevant gene targets that are important in our research and drug discovery efforts,” said Tage Honor, Vice President, Discovery Research at Purdue Pharma. “The proven advantages of regulating the endogenous gene, as Sangamo’s ZFP TFs do, will help us to further accelerate our efforts in the very competitive field of pain therapy." Proteins known as transcription factors are critical components for the expression of genes in all organisms. A transcription factor regulates gene expression by recognizing and binding to a specific DNA sequence associated with a particular gene and causing that gene to be activated or repressed. By using its ZFP TF technology to activate or repress a gene believed to be at the root of a disease, Sangamo provides researchers with a tool that enables them to more efficiently discover new drugs that are effective against the proteins encoded by such genes.

About Sangamo

Sangamo BioSciences, Inc., of Richmond, CA, is focused on the research and development of novel transcription factors for the regulation of gene expression. The company’s most advanced therapeutic development program involves the use of transcription factors for the treatment of peripheral and cardiovascular disease. Other therapeutics development programs are focused on cancer, ophthalmic and infectious diseases. Sangamo’s proprietary technology enables the engineering of transcription factors known as zinc finger DNA-binding proteins, or ZFPs. By engineering ZFPs so that they can recognize a specific gene, Sangamo has created ZFP transcription factors (ZFP TFs) that can control gene expression and, consequently, cell function. The company is developing ZFP TFs as a fundamentally enabling technology for commercial applications in human therapeutics, pharmaceutical discovery, clinical diagnostics, agriculture, and industrial biotechnology. Over twenty leading pharmaceutical and biotechnology companies have utilized ZFP TFs.

About Purdue Pharma L.P.

Purdue Pharma L.P. and its associated U.S. companies are privately held pharmaceutical companies known for pioneering research on persistent pain and associated treatments. Purdue is engaged in the research, development, production, and distribution of both prescription and over-the-counter medications and hospital products. The company has two separate research facilities in the United States. In Ardsley, New York, Purdue researchers are developing innovative formulations for compounds in the pipeline. Scientists in Cranbury, New Jersey are exploring the frontiers of scientific research to discover new weapons against cancer and pain. Additional information about Purdue can be found at www.purduepharma.com.

Investors Please Note

This press release may contain forward-looking statements based on Sangamo’s current expectations. These forward-looking statements include, without limitation, references to the research and development of novel ZFP TFs and applications of Sangamo’s ZFP TF technology platform. Actual results may differ materially from these forward-looking statements due to a number of factors, including technological challenges, Sangamo’s ability to develop commercially viable products and technological developments by our competitors. See the company’s SEC filings, and in particular, the risk factors described in the company’s Annual Report on Form 10-K and its most recent 10-Q. Sangamo and Purdue Pharma assume no obligation to update the forward-looking information contained in this press release.