Synthorx, Inc., a Delaware corporation (“Synthorx” or the “Company”), entered into an Agreement and Plan of Merger with Sanofi, a French société anonyme (“Parent”), and Thunder Acquisition Corp., a Delaware corporation and an indirect wholly owned subsidiary of Parent (“Purchaser”). Following the completion of the Offer, on January 23, 2020, pursuant to the terms of the Merger Agreement and in accordance with Section 251(h) of the General Corporation Law of the State of Delaware (the “DGCL”), Purchaser merged with and into the Company (the “Merger”), with the Company continuing as the surviving corporation (the “Surviving Corporation”) and an indirect wholly owned subsidiary of Parent. Pursuant to the Merger Agreement, effective immediately after the Effective Time, each of (i) Vickie Capps, Jay Lichter, Ph.D., Peter Kolchinsky, Ph.D., Andrew Powell, J.D., Pratik Shah, Ph.D. Laura Shawver, Ph.D. and Peter Thompson, M.D. ceased serving as a member of the board of directors of the Company and each committee thereof and (ii) Laura Shawver, Ph.D., Tighe Reardon, Joseph Leveque M.D. and Marcos Milla, Ph.D. ceased serving as an officer of the Company. Further, pursuant to the Merger Agreement and effective immediately after the Effective Time, John Reed and Marie Debans, the directors of, and President and Treasurer respectively of, Thunder Acquisition Corp., immediately prior to the Effective Time became the directors and officers of the Surviving Corporation, holding the same positions.