December 7, 2018 Jack A. Khattar President and Chief Executive Officer Supernus Pharmaceuticals, Inc. 1550 East Gude Drive Rockville, MD 20850 Re: Supernus Pharmaceuticals, Inc. Form 10-K for the Fiscal Year Ended December 31, 2017 Filed March 1, 2018 File No. 001-35518 Dear Mr. Khattar: We have completed our review of your filing. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sincerely, Division of Corporation Finance Office of Healthcare & Insurance