EXHIBIT 99.1 SIGNATURES FOR FORM 3 SANOFI-AVENTIS By: /s/ John Felitti ------------------------------------------ Name: John Felitti Title: Associate Vice President, Corporate Law, Financial & Securities Law Date: 04/06/2011 GC Merger Corp. By: /s/ Gregory Irace ------------------------------------------ Name: Gregory Irace Title: President Date: 04/06/2011