On December 5, 2018, Mereo BioPharma Group plc, Mereo US Holdings Inc., Mereo MergerCo One Inc, and OncoMed Pharmaceuticals, Inc. entered into an Agreement and Plan of Merger and Reorganization, pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set in the Merger Agreement, Merger Sub will merge with and into the Company, with the Company surviving the merger as a wholly owned subsidiary of HoldCo, and an indirect wholly-owned subsidiary of Mereo. The respective boards of directors of the Company and Mereo have each unanimously approved the Merger Agreement. In connection with the merger the Company terminated the employment of: (i) John A. Lewicki, Ph.D., who was serving as the Company's President and Chief Executive Officer, effective immediately prior to the closing of the Merger; (ii) Austin Gurney, Ph.D., who was serving as the Company's Chief Scientific Officer and Senior Vice President, Research, effective as of December 21, 2018; (iii) Alicia J. Hager, Ph.D., who was serving as the Company's Senior Vice President and General Counsel, effective immediately prior to the closing of the Merger; and (iv) Yvonne Li, who was serving as the Company's Vice President, Finance, Controller and Administration, effective immediately prior to the closing of the Merger.