US gene therapy group Sangamo Therapeutics has completed its purchase of French biotech TxCell, which will now operate as a subsidiary of Sangamo and remain in Valbonne.

The Richmond, California-headquartered company has acquired 53% of TxCell’s share capital and was due to file on Oct. 2 a cash tender offer for the remaining shares. Subject to obtaining at least 95% of the share capital, Sangamo will then launch a squeeze-out procedure.  Once the squeeze-out process is completed, Sangamo will delist TxCell.

TxCell’s CEO, Stephane Boissel, has joined Sangamo as executive vice president, corporate strategy, with effect from Oct. 2 and will be based in the US.

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

Sangamo said it 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 has shown that antigen specific CAR-Tregs can deliver potent immunosuppression locally to targeted tissues.

“As we move to complete the final steps of this acquisition, we’re looking ahead and planning to initiate the first CAR-Treg clinical trial in the solid organ transplant rejection setting in 2019,” 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.”

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 treating autoimmune diseases.