[STOCK PURCHASE AGREEMENT “Agreement” Selling Stockholder Mr. Lam Buyer PRC STOCK PURCHASE AGREEMENT (the WHEREAS: Company 1. Common Shares 2. NOW THEREFORE, in consideration of the foregoing, of the mutual promises herein set forth, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows: 1. PURCHASE AND] []

[JOINT FILING AGREEMENT Dated: May 15, 2013 WP X Biologics LLC Scott A. Arenare Attorney-in-Fact* WARBURG PINCUS PRIVATE EQUITY X, L.P.] [REGISTRATION RIGHTS AGREEMENT Agreement Company Purchaser This Registration Rights Agreement (this “ RECITALS Selling Stockholder Purchase Agreement Shares Common Stock The Company and the Purchaser hereby agree as follows: Definitions 1. 2009 Holders “ 2010 Holders “ Advice “ Affiliate “ Agreement “ Business Day “ Company “ Commission “ Common Stock “ Effectiveness Date “ Effectiveness Period “ Exchange] [ESCROW AGREEMENT WP X Biologics LLC Ms. Lin Ling Li WHEREAS, NOW THEREFORE 1. Appointment The Parties hereby appoint the Escrow Agent as their escrow agent for the purposes set forth herein, and the Escrow Agent hereby accepts such appointment under the terms and conditions set forth herein. 2. Escrow Document 2.1 Party B agrees to deposit with the Escrow] [AGREEMENT Agreement WP X Ms. Li Mr. Lin Parties Party This AGREEMENT (this “ WHEREAS Share Purchase Agreement WHEREAS Escrow Agreement Escrow Agent WHEREAS NOW, THEREFORE 1. Definitions 2. Delivery of Release Notice (a) HK Lawsuit Resolution Plaintiffs (b) Within ten (10) Business Days of the HK Lawsuit Resolution, the Parties shall deliver the Release Notice to the Escrow Agent] [CUSIP No. 16938C106 2 1. Names of reporting persons.]