UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

Amendment No. 1

CURRENT REPORT

Pursuant to Section 13 or Section 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 6, 2020 (August 5, 2020)

AVADEL PHARMACEUTICALS PLC

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: +353 1 920 1000

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation to the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

*American Depositary Shares may be evidenced by American Depositary Receipts. Each American Depositary Share represents one (1) Ordinary Share.

** Not for trading, but only in connection with the listing of American Depositary Shares on The Nasdaq Global Market.

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Explanatory Note

The purpose of this Amendment No. 1 to the Current Report on Form 8-K filed by Avadel Pharmaceuticals plc (the “Company”) with the Securities and Exchange Commission on August 6, 2020 (the “Original Form 8-K”) is to disclose the number of votes that were voted “Against” each director nominee at the Company’s 2020 Annual Meeting of Shareholders. The number of votes voted “Against” each director nominee was inadvertently omitted from the Original Form 8-K.

On August 5, 2020, the Avadel Pharmaceuticals plc (the “Company”) held its 2020 Annual Meeting of Shareholders (the “Annual Meeting”). Proxies were solicited pursuant to the Company’s definitive proxy statement filed on April 27, 2020, with the Securities and Exchange Commission under Section 14(a) of the Securities Exchange Act of 1934, as amended. The number of shares of ordinary shares, par value $0.01 per share, of the Company (the “Ordinary Shares”) entitled to vote at the Annual Meeting was 58,129,038. The number of shares of Ordinary Shares present or represented by valid proxy at the Annual Meeting was 58,046,543, thus establishing a quorum for the Annual Meeting. All matters submitted to a vote of the Company’s stockholders at the Annual Meeting were approved and the director nominees were elected. The voting results reported below are final.

The following is a tabulation of the voting on the proposals presented at the Annual Meeting:

Proposal 1: By separate resolutions, to elect Gregory J. Divis, Dr. Eric J. Ende, Geoffrey M. Glass, Linda S. Palczuk, Dr. Mark A. McCamish and Peter Thornton as directors to the Board of Directors (the “Board”), each to serve a one-year term expiring at the conclusion of the next annual general meeting of shareholders.

Proposal 2: To ratify, in a non-binding vote, the appointment of Deloitte & Touche LLP as the Company’s independent registered public auditor and accounting firm for the fiscal year ending December 31, 2020 and to authorize, in a binding vote, the Audit Committee of the Board to set the independent registered public auditor and accounting firm remuneration.

Proposal 3: To approve, on a non-binding advisory basis, the compensation of the named executive officers of the Company.

Proposal 4: To approve the Avadel Pharmaceuticals plc 2020 Omnibus Incentive Compensation Plan.

Based on the foregoing, Gregory J. Divis, Dr. Eric J. Ende, Geoffrey M. Glass, Linda S. Palczuk, Dr. Mark A. McCamish and Peter Thornton were elected as directors, each to serve a one-year term expiring at the conclusion of the 2021 annual general meeting of shareholders and until each such director’s successor shall have been duly elected and qualified or until his or her earlier resignation or removal. Deloitte & Touche LLP was ratified as the Company’s registered public accounting firm for the fiscal year ending December 31, 2020. The compensation of the Company’s named executive officers was approved. The Avadel Pharmaceuticals plc 2020 Omnibus Incentive Compensation Plan was approved.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has caused this report to be signed on its behalf by the undersigned hereunto duly authorized.