Sanofi began its tender offer to acquire all common shares of immuno-oncology company Synthorx Inc. at $68 each.

The deal is valued at $2.5 billion, and the acquisition is expected to boost French drugmaker Sanofi's oncology and immuno-oncology pipeline with Synthorx's lead asset, THOR-707, which is being studied as a potential treatment for multiple solid tumor types.

Sanofi's offer is expected to expire Jan. 22, 2020.

Morgan Stanley & Co. is acting as financial adviser to Sanofi, with Weil Gotshal & Manges LLP serving as legal counsel. Centerview Partners LLC is the exclusive financial adviser to Synthorx, while Cooley LLP is acting as legal counsel.