Sangamo BioSciences, Inc. Presents Preclinical Data From ZFP Therapeutic For Age- Related Macular Degeneration

RICHMOND, Calif., May 2 /PRNewswire-FirstCall/ -- Sangamo BioSciences, Inc. today announced that positive preclinical animal efficacy data from its program to develop a ZFP Therapeutic(TM) for age-related "wet" macular degeneration (AMD) were presented at the Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO), on May 1, 2006, in Fort Lauderdale, Florida. The study demonstrates the efficacy of zinc finger DNA-binding protein transcription factors (ZFP TFTM) in an animal model of macular degeneration and was conducted by researchers at the Wilmer Eye Institute, Johns Hopkins University School of Medicine.

"We have engineered a ZFP TF(TM) designed to regulate a well-established target for AMD, the gene for pigment epithelium-derived factor (PEDF), and our data show that treatment with this ZFP Therapeutic produces a statistically significant reduction in the amount of blood vessel growth in the eye compared to the control treatment," said Dr. Dale Ando, Sangamo's vice president of therapeutic development and chief medical officer. "Anti-angiogenic therapies have demonstrated great promise. However, all require administration via intraocular injection. This means that in addition to efficacy, an important criterion in developing a therapeutic for AMD is a consideration of the frequency of administration of the therapeutic. We are delivering our ZFP Therapeutic in a formulation that we believe will provide long-term expression of PEDF and thus less frequent injections into the eye. We have initiated further animal studies to investigate the durability of effect of the ZFP TF."

A mouse model of AMD was used to test a ZFP TF(TM) designed to "turn on" the gene for PEDF, the eye's key natural regulator of normal blood vessel growth and a neuro-protective agent for the photoreceptors (cells in the eye that respond to light). Mice were treated with the ZFP TF activator of PEDF or a control administered into the vitreous space of the eye and six weeks later a laser was used to induce choroidal neovascularization (CNV), or abnormal blood vessel formation, in the eye. After a further two weeks the size of the laser-induced CNV was measured in both ZFP TF and control-treated eyes and compared. ZFP TF treatment resulted in a statistically significant reduction in CNV compared to control.

"As the population ages, the number of cases of macular degeneration in the U.S. is expected to increase significantly," said Edward Lanphier, Sangamo's president and CEO. "It is estimated that the current $750 million market for drugs to treat AMD will reach approximately $1.8 billion by 2010. We believe that a ZFP Therapeutic(TM) approach may have significant advantages over existing therapies on the market and currently in development as direct regulation of target genes by ZFP TFs may be more efficient than RNAi and antibody approaches that attempt to "mop up" the many copies of the RNA or protein products of these genes. The potential of PEDF to protect the photoreceptors damaged by leaky, abnormal blood vessels characteristic of AMD and its reported ability to inhibit and even cause regression of blood vessel growth make it a key potential target for the treatment of AMD."

AMD is the leading cause of blindness in the United States for those aged 55 and over and affects an estimated 12 million people. The "wet" form of the disease is responsible for most of the severe loss of vision and is caused by growth of abnormal blood vessels under the central part of the retina or macula. These new blood vessels may then bleed and leak fluid causing the macula to bulge or lift up, thus distorting or destroying central vision. The Macular Degeneration Foundation estimates that there are approximately 200,000 new cases of wet macular degeneration in the United States annually. Each year, 1.2 million of the estimated 12 million people in the US with AMD will suffer severe central vision loss.

About Sangamo

Sangamo BioSciences, Inc. is focused on the research and development of novel DNA-binding proteins for therapeutic gene regulation and modification. The most advanced ZFP Therapeutic(TM) development programs are currently in Phase I clinical trials for evaluation of safety in patients with peripheral artery disease and diabetic neuropathy. Other therapeutic development programs are focused on ischemic heart disease, congestive heart failure, neuropathic pain, and infectious and monogenic diseases. Sangamo's core competencies enable the engineering of a class of DNA-binding proteins known as zinc finger DNA-binding proteins (ZFPs). By engineering ZFPs that recognize a specific DNA sequence Sangamo has created ZFP transcription factors (ZFP TF(TM)) that can control gene expression and, consequently, cell function. Sangamo is also developing sequence-specific ZFP Nucleases (ZFN(TM)) for therapeutic gene modification as a treatment for a variety of monogenic diseases, such as sickle cell anemia, and for infectious diseases, such as HIV. For more information about Sangamo, visit the company's web site at

This press release contains forward-looking statements regarding Sangamo's current expectations. These statements are not guarantees of future performance and are subject to certain risks, uncertainties and assumptions that are difficult to predict. Factors that could cause actual results to differ include the early stage of ZFP Therapeutic development, uncertainties related to the timing of initiation and completion of clinical trials, whether clinical trial results will validate and support the safety and efficacy of ZFP Therapeutics and advances and developments with respect to competing technologies. Further, there can be no assurance that the necessary regulatory approvals will be obtained or that Sangamo will be able to develop commercially viable gene based therapeutics. Actual results may differ from those projected in forward-looking statements due to risks and uncertainties that exist in the company's operations and business environments. These risks and uncertainties are described more fully in the company's' Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q as filed with the Securities and Exchange Commission. Forward-looking statements contained in this announcement are made as of this date and will not be updated.

Sangamo BioSciences, Inc.

CONTACT: Elizabeth Wolffe, Ph.D., of Sangamo BioSciences, Inc.,+1-510-970-6000, ext. 271, or; or Justin Jackson(media) of Burns McClellan, Inc., +1-212-213-0006 or,for Sangamo BioSciences, Inc.

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