Companies also announce Phase 1/2 clinical trial evaluating SB-525 in adults with severe hemophilia A is now open for enrollment

Sangamo Therapeutics, Inc. (NASDAQ: SGMO) and Pfizer Inc. (NYSE: PFE) announced today that the European Medicines Agency (EMA) has granted orphan medicinal product designation (OMPD) to SB-525, a clinical stage cDNA gene therapy candidate for hemophilia A. The EMA’s OMPD is granted to medicines intended for the treatment, prevention or diagnosis of life-threatening or chronically debilitating conditions that are rare and affect less than five in 10,000 persons in the European Union (EU). The designation provides incentives to advance the development and commercialization of orphan medicines, which include access to the EU centralized authorization procedure and potential for market exclusivity for a period of up to ten years.

SB-525 uses a recombinant adeno-associated virus (rAAV) to deliver a human Factor VIII cDNA construct and proprietary, synthetic liver-specific promoter to the nucleus of liver cells with a single infusion. The therapy is being investigated as a single-treatment strategy intended to provide continuous, therapeutic expression of Factor VIII protein.

In May 2017, Sangamo and Pfizer entered into an exclusive, global collaboration and license agreement to develop and commercialize gene therapy programs for hemophilia A, including SB525. The U.S. Food and Drug Administration (FDA) has already granted Orphan Drug and Fast Track designation to SB-525 for the treatment of hemophilia A. The FDA has also cleared an Investigational New Drug application for this program, and a Phase 1/2 clinical trial evaluating SB525 in adults with hemophilia A is now open and screening subjects for enrollment. Initial data from this study are expected in late 2017 or early 2018. Under the collaboration and license agreement between the two companies, Pfizer will be responsible for any subsequent clinical trials and the commercialization of SB-525.

About Hemophilia A

Hemophilia A is a monogenic, rare bleeding disorder in which the blood does not clot normally. It is caused by mutations in the F8 gene which encodes Factor VIII clotting protein that helps the blood clot and stop bleeding when blood vessels are injured. Individuals with this mutation experience bleeding episodes after injuries and spontaneous bleeding episodes that often lead to joint disease such as arthritis. According to the Centers for Disease Control and Prevention, hemophilia occurs in about one of every 5,000 male births, with an estimated 20,000 males in the U.S. living with the disorder.

About Sangamo Therapeutics

Sangamo Therapeutics, Inc. is focused on translating ground-breaking science into genomic therapies that transform patients' lives using the company's industry leading platform technologies in genome editing, gene therapy, gene regulation and cell therapy. The Company is conducting Phase 1/2 clinical trials in Hemophilia A and Hemophilia B, and lysosomal storage disorders MPS I and MPS II. Sangamo has an exclusive, global collaboration and license agreement with Pfizer Inc. for gene therapy programs for Hemophilia A, with Bioverativ Inc. for hemoglobinopathies, including beta thalassemia and sickle cell disease, and with Shire International GmbH to develop therapeutics for Huntington's disease. In addition, it has established strategic partnerships with companies in non-therapeutic applications of its technology, including Sigma-Aldrich Corporation and Dow AgroSciences. For more information about Sangamo, visit the Company's website at www.sangamo.com.

Forward Looking Statements This press release may contain forward-looking statements based on Sangamo's current expectations. These forward-looking statements include, without limitation references relating to the benefit of orphan medicinal product designation, including accelerated regulatory approval of SB-525 and potential market exclusivity in the EU, the potential of SB-525 to treat hemophilia, and the expected timing of releasing clinical trial data from SB-525 studies. Actual results may differ materially from these forward-looking statements due to a number of factors, including uncertainties relating to substantial dependence on the clinical success of lead therapeutic programs, the initiation and completion of stages of our clinical trials, whether the clinical trials will validate and support the tolerability and efficacy of ZFNs, technological challenges, Sangamo's ability to develop commercially viable products and technological developments by our competitors. For a more detailed discussion of these and other risks, please see Sangamo's SEC filings, including the risk factors described in its Annual Report on Form 10-K and its most recent Quarterly Report on Form 10-Q. Sangamo Therapeutics, Inc. assumes no obligation to update the forward-looking information contained in this press release.

Pfizer and Rare Disease

Rare disease includes some of the most serious of all illnesses and impacts millions of patients worldwide,i representing an opportunity to apply our knowledge and expertise to help make a significant impact on addressing unmet medical needs. The Pfizer focus on rare disease builds on more than two decades of experience, a dedicated research unit focusing on rare disease, and a global portfolio of multiple medicines within a number of disease areas of focus, including hematology, neuroscience, and inherited metabolic disorders.ii

Pfizer Rare Disease combines pioneering science and deep understanding of how diseases work with insights from innovative strategic collaborations with academic researchers, patients, and other companies to deliver transformative treatments and solutions. We innovate every day leveraging our global footprint to accelerate the development and delivery of groundbreaking medicines and the hope of cures.

Click here to learn more about our Rare Disease portfolio and how we empower patients, engage communities in our clinical development programs, and support programs that heighten disease awareness and meet the needs of patient families.

Pfizer Inc: Working together for a healthier world®

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products. Our global portfolio includes medicines and vaccines as well as many of the world's best-known consumer health care products. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 150 years, Pfizer has worked to make a difference for all who rely on us. For more information, please visit us at www.pfizer.com. In addition, to learn more, follow us on Twitter at @Pfizer and @Pfizer_News, LinkedIn, YouTube and like us on Facebook at Facebook.com/Pfizer.

Pfizer Disclosure Notice:

The information contained in this release is as of June 7, 2017. Pfizer assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.

This release contains forward-looking information about an investigational hemophilia A agent, SB-525, including its potential benefits, that involves substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Risks and uncertainties include, among other things, the uncertainties inherent in research and development, including the ability to meet anticipated clinical study commencement and completion dates as well as the possibility of unfavorable study results, including unfavorable new clinical data and additional analyses of existing clinical data; risks associated with initial data, including the risk that the final results of the Phase I/2 study for SB-525 and/or additional clinical trials may be different from (including less favorable than) the initial data results and may not support further clinical development; whether and when any applications may be filed with regulatory authorities for SB-525; whether and when regulatory authorities may approve any such applications, which will depend on the assessment by such regulatory authorities of the benefit-risk profile suggested by the totality of the efficacy and safety information submitted; decisions by regulatory authorities regarding labeling and other matters that could affect the availability or commercial potential of SB-525; and competitive developments.

A further description of risks and uncertainties can be found in Pfizer's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned "Risk Factors" and "Forward-Looking Information and Factors That May Affect Future Results", as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

Contact
Sangamo Therapeutics, Inc. 
McDavid Stilwell 
510-970-6000, x219 
[email protected]

Varant Shirvanian 
510-970-6000 x205 
[email protected]