UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 Commission file number: 000-28508 AVADEL PHARMACEUTICALS PLC (Exact name of registrant as specified in its charter) Ireland 98-1341933 State or other jurisdiction of incorporation or organization (I.R.S. Employer Identification No.) 10 Earlsfort Terrace Dublin 2, Ireland D02 T380 Not Applicable (Ad ...