The Proposed Acquisition Would Combine Sangamo’s Ex Vivo Gene Editing Capabilities and TxCell’s Treg Expertise and Would Position Sangamo as a Leader in CAR-Treg Development

Initiation of First CAR-Treg Clinical Trial Expected in 2019

RICHMOND, CA, USA and VALBONNE, France I July 23, 2018 I Sangamo Therapeutics, Inc. (Nasdaq: SGMO) and TxCell S.A. (ENXTPA: TXCL) announced today that they have entered into a definitive agreement on July 20, 2018 pursuant to which Sangamo will, following the completion of the contemplated acquisition of a majority stake of TxCell, file a simplified cash tender offer for the purchase of all then outstanding ordinary shares of TxCell, at a price of €2.58 per share in cash, or approximately €72 million, on a debt-free and cash-free basis. Subject to satisfaction of closing conditions (including in particular those relating to regulations governing foreign investments in France), Sangamo expects to complete the transaction in the fourth quarter of 2018.

With its highly skilled and experienced team, TxCell is a leader in the emerging field of regulatory T cell (Treg) development for immunological diseases, one of Sangamo’s stated therapeutic areas of focus for its proprietary product candidate pipeline. Tregs are a naturally occurring subset of T cells and are critical for maintaining immune homeostasis within the body by induction and maintenance of tolerance to self-antigens.

Sangamo intends to evaluate the potential of CAR-Treg (Tregs genetically modified with a chimeric antigen receptor, or CAR) therapies to prevent graft rejection in solid organ transplant and for the treatment of autoimmune diseases such as Crohn’s disease and multiple sclerosis. Preclinical research provides proof of concept that antigen specific CAR-Tregs can deliver potent immunosuppression locally to targeted tissues. By contrast, currently available anti-TNF alpha small molecule and monoclonal antibody drugs are associated with global, non-specific immune suppression.

Sangamo expects that the proposed acquisition of TxCell would accelerate the Company’s entry into the clinic with a CAR-Treg therapy. In 2019, Sangamo expects to submit a clinical trial authorization application in Europe for TxCell’s first CAR-Treg investigational product candidate for solid organ transplant, and to initiate a Phase 1/2 clinical trial later in the year. In addition, Sangamo intends to use its zinc finger nuclease (ZFN) gene editing technology to develop next-generation autologous and allogeneic CAR-Treg cell therapies for use in treating autoimmune diseases.

We are thrilled to announce this proposed acquisition which would combine TxCell’s Treg expertise with our ex vivo gene editing capabilities, positioning Sangamo as a leader in the emerging field of CAR-Treg cell therapy,” said Sandy Macrae, CEO of Sangamo. “We believe CAR-Treg therapies will prove to be as exciting for immunology as CAR-T has been for oncology.

We are excited to combine with Sangamo for their experience and technical expertise in gene-edited cell therapy, and we believe Sangamo’s ZFN editing technology will facilitate the precise genetic modifications needed to create a new class of Treg-based antigen and tissue specific immunosuppressive medicines,” said Stephane Boissel, CEO of TxCell. “Progressing such CAR-Treg products in clinical development and towards commercialization would require expertise and financial resources that were impossible for us to get as a stand-alone business at a reasonable cost.

About the Transaction

The filing of the cash simplified tender offer is subject to the completion of the purchase by Sangamo of TxCell ordinary shares (at a price of €2.58 per share in cash) representing approximately 53% of share capital and voting rights of TxCell in accordance with the stock purchase agreement Sangamo entered into on July 20, 2018 with certain shareholders of TxCell (i.e., Mr. Stéphane Boissel who has committed to sell his shares representing less than 1% of the share capital and voting rights, FCPR Auriga Ventures II who has committed to sell its shares representing 16% of the share capital and voting rights, FCPR BIOAM who has committed to sell its shares representing 1% of the share capital and voting rights, FCPR BIOAM 1B who has committed to sell its shares representing less than 1% of the share capital and voting rights, Large Venture who has committed to sell its shares representing 10% of the share capital and voting rights, FCPR Innobio who has committed to sell its shares representing 15% of the share capital and voting rights, François Meyer who has committed to sell his shares representing less than 2% of the share capital and voting rights, Belsize who has committed to sell its shares representing less than 1% of the share capital and voting rights and YA II PN, Ltd who has committed to sell its shares representing 8% of the share capital and voting rights), it being specified that the completion of the sale of this majority stake is subject to conditions precedent, including in particular, those relating to regulations governing foreign investments in France and the delivery of a favorable report from HAF Audit & Conseil (represented by Mr. Olivier Grivillers), appointed as independent appraiser by TxCell’s board of directors on July 20, 2018, in compliance with sections 261-1-I and II of the General Regulation of the AMF (the French Financial Markets Authority). It is specified that the terms and conditions of the offer and the price of €2.58 per share proposed in the simplified tender offer will be subject to the independent expert’s conclusion on the terms and conditions of the offer and in particular the fairness of the proposed share price and the AMF’s compliance decision on the proposed offer.

The warrants issued by TxCell (which are not admitted for trading) will not be targeted by the cash tender offer because they will either be waived in the case of out of the money warrants, or, in the case of in the money warrants, exercised prior to the closing of the offer and the resulting shares will be either sold to Sangamo under the stock purchase agreement or tendered to the offer.

Subject to obtaining at least 95% of the share capital and voting rights of TxCell upon completion of the simplified tender offer, Sangamo would launch a squeeze-out procedure.  TxCell will be a subsidiary of Sangamo operating under the name Sangamo Therapeutics SA. Following the completion of the squeeze-out procedure, Sangamo intends to delist TxCell. TxCell’s operations will remain based in Valbonne, France.

Conference Call Information

Sangamo will host a conference call on Monday, July 23, 2018, at 8:00 a.m. ET, which will be open to the public. The call will also be webcast live and can be accessed via a link on the Sangamo Therapeutics website in the Investors and Media section under Events and Presentations.

The conference call dial-in numbers are (877) 377-7553 for domestic callers and (678) 894-3968 for international callers. The conference ID number for the call is 9184627. For those unable to listen in at the designated time, a conference call replay will be available for one week following the conference call, from approximately 11:00 a.m. ET on July 23, 2018 to 11:00 a.m. ET on July 30, 2018. The conference call replay numbers for domestic and international callers are (855) 859-2056 and (404) 537-3406, respectively. The conference ID number for the replay is 9184627.

About Sangamo Therapeutics, Inc.

Sangamo Therapeutics, Inc. is focused on translating ground-breaking science into genomic therapies that transform patients’ lives using Sangamo’s platform technologies in genome editing, gene therapy, gene regulation and cell therapy.

For more information about Sangamo, visit Sangamo’s website at www.sangamo.com.

About TxCell S.A.

TxCell S.A. is a biotechnology company that develops platforms for innovative, personalized T cell immunotherapies for the treatment of severe inflammatory and autoimmune diseases with high unmet medical need. TxCell is targeting transplantation as well as a range of autoimmune diseases (both T-cell and B-cell-mediated), such as multiple sclerosis, rheumatoid arthritis, inflammatory bowel diseases or inflammatory skin diseases.

SOURCE: Sangamo Therapeutics