ACHN 2018 Proxy Statement

Dr. Verwiel has served as a director of Avexis, Inc., a publicly traded, clinical-stage gene therapy company. In August 2015, Dr. Verwiel was appointed as an observer of the Board of Directors of Bavarian Nordic A/S, a publicly traded biopharmaceutical vaccine company and was appointed as a Director on April 20, 2016. Dr. Verwiel is also Chairman of the Board of ObsEva SA, a publicly traded company developing drugs addressing conditions relating to women’s reproductive health, where he became a director in January 2016. In July 2017, Dr. Verwiel was appointed to the Board of Intellia Inc., a publicly traded gene editing company. From March 2012 to September 2014, Dr. Verwiel was a director of InterMune, Inc., a publicly traded biotechnology company that was acquired by Roche in 2014. Dr. Verwiel was also a member of the Board of Directors of the Biotechnology Industry Organisation (BIO) from February 2013 to April 2014. Dr. Verwiel holds an M.D. from Erasmus University, Rotterdam in The Netherlands and an M.B.A. from INSEAD, Fontainebleau in France. Board Committees: Audit; Compensation (Chair); Strategy Skills and Qualifications: We believe that Dr. Verwiel’s expertise in healthcare, marketing, strategy development and financial operations, as well as his experience as a chief executive officer of a biopharmaceutical company, and his board service for a number of publicly traded biopharmaceutical companies, positions him to make valuable contributions to our Board of Directors and provide a valuable source of experience for our management team. Directors Whose Terms Expire in 2020 (Class II Directors) Michael D. Kishbauch, age 69 . Mr. Kishbauch has served as a director of Achillion since July 2004. Mr. Kishbauch was President and Chief Executive Officer of Achillion from July 2004 until May 2013. In September 2013, he retired from Achillion. From September 1996 to July 2004, Mr. Kishbauch founded and served as President and Chief Executive Officer of OraPharma, Inc., a publicly traded, commercial-stage pharmaceutical company focused on oral health care, which was acquired by Johnson & Johnson in 2003. Prior to OraPharma, Inc., Mr. Kishbauch held senior management positions with MedImmune, Inc., a biotechnology company. Since September 2013, Mr. Kishbauch has served on the Board of Directors of Progenics Pharmaceuticals, Inc., a publicly traded oncology company, and has served on the Board of Directors of Catabasis Pharmaceuticals, Inc., a publicly traded rare disease biopharmaceutical company since April 2016. From September 2014 until December 2016, Mr. Kishbauch served on the Board of Directors of TetraLogic Pharmaceuticals, Inc., a publicly traded biopharmaceutical company. Mr. Kishbauch holds an M.B.A. from the Wharton School of the University of Pennsylvania and a B.A. in biology from Wesleyan University. Mr. Kishbauch has held senior management positions in the life sciences industry for over 28 years. Board Committees: Compliance Skills and Qualifications: Our Board of Directors believes that Mr. Kishbauch’s extensive operational, strategic, product launch and sales and marketing experience, coupled with his previous service as our Chief Executive Officer and his board experience with several other life sciences companies, including rare disease companies qualify him to serve on the Board of Directors and adds significant value to our Board of Directors. Robert L. Van Nostrand, age 61. Mr. Van Nostrand has served as a director of Achillion since April 2007. Mr. Van Nostrand is currently on the Board of Directors of SELLAS Life Sciences Group, Inc. (since January 2018), a publicly traded biopharmaceutical company focused on the development of novel cancer immunotherapies, Intra-Cellular Therapies (since January 2014), a publicly traded biopharmaceutical company developing therapies for CNS disease, Yield10 Bioscience, Inc., formerly Metabolix, Inc. (since October 2006), a publicly traded bio agricultural company, and Enumeral Biomedical Holdings, Inc. (since December 2014), a publicly traded biotechnology company developing novel antibody immunotherapies relevant to cancer, infectious diseases and inflammatory diseases. Mr. Van Nostrand was Executive Vice President and Chief Financial Officer of Aureon Laboratories, Inc., a pathology life science company, from January 2010 to July 2010. Prior to joining Aureon 12