Executive Officer Compensation, Bonuses and Equity Grants

On December 18, 2012, the Compensation Committee of the Board of Directors (the "Compensation Committee") of Achillion Pharmaceuticals, Inc. (the "Company") authorized the payment of annual bonus awards to the Company's principal executive officer, principal financial officer and other Named Executive Officers (as defined in Item 402(a)(3) of Regulation S-K) for work performed by each such officer during the year ended December 31, 2012 (the "2012 Bonus Award") and approved annual base salaries to be effective as of January 1, 2013. Bonus awards for each officer are based on the Company's overall performance in the fiscal year, as well as each officer's individual performance as measured against pre-determined corporate and personal objectives. The target bonus amounts previously established by the Company's Board of Directors are 35% of the base salary for each senior vice president or executive vice president, 40% of the base salary for the president of research and development and 60% of the base salary for the Company's chief executive officer. In addition, in consideration of particularly positive achievements during 2012 by our president of research and development and our chief financial officer, the Compensation Committee, in their discretion, granted additional awards as shown below.

In addition to receiving bonus awards, each executive officer was granted an incentive stock option to purchase shares of the Company's common stock at a purchase price equal to $8.64 per share, representing the closing price of the Company's common stock on the Nasdaq Global Select Stock Market on the date of grant. Such options are subject to the provisions of the Company's 2006 Stock Incentive Plan, as amended (the "Plan"), vest over a period of four years, and have a term of ten years. The following table sets forth the 2012 Bonus Awards and equity option awards and the 2013 annual base salary amounts for each such officer:

                                                                                Total
                                                                                 2012
                                                                                Bonus           No. Shares
                                                                                Award           Subject to
                                                                2012             and               2012                            Target
                                            2012 Bonus       Additional       Additional       Performance       2013 Base         Bonus
Name of Executive Officer                     Award            Award            Awards         Equity Grant        Salary        Percentage
Michael D. Kishbauch                       $    292,338                      $    292,338            350,000     $  496,200               60 %
Milind S. Deshpande, Ph.D.                 $    161,272     $     40,000     $    201,272            145,000     $  387,400               40 %
Gautam Shah, Ph.D.                         $    117,282                      $    117,282            145,000     $  334,400               35 %
Mary Kay Fenton                            $    113,176     $     25,000     $    138,176            145,000     $  326,400               35 %
Joseph Truitt                              $    109,558                      $    109,558            145,000     $  313,300               35 %