ACHN 2018 Proxy Statement

Under procedures approved by a majority of the independent directors, communications are forwarded to all directors if they relate to important substantive matters and include suggestions or comments that the Chairman of the Board or Chairman of the Nominating and Corporate Governance Committee, as appropriate, considers to be important for the directors to know. In general, communications relating to corporate governance and corporate strategy are more likely to be forwarded than communications relating to ordinary business affairs, personal grievances and matters as to which we tend to receive repetitive or duplicative communications. Stockholders who wish to send communications on any topic to the Board of Directors should address such communications to Board of Directors, c/o Secretary, Achillion Pharmaceuticals, Inc., 300 George Street, New Haven, Connecticut 06511. Code of Business Conduct and Ethics We have adopted a written Code of Business Conduct and Ethics that applies to our directors, officers and employees. We have posted a copy of the code on our website, www.achillion.com . In addition, we intend to post on our website all disclosures that are required by law or Nasdaq Global Select Market listing standards concerning any amendments to, or waivers of, our code. 33