Alkermes plc Announces Increased Offer to Acquire Avadel Pharmaceuticals plc NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A

Alkermes plc Announces Increased Offer to Acquire

Avadel Pharmaceuticals plc

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN

WHOLE OR IN PART, IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS

OF SUCH JURISDICTION

DUBLIN, November 19,

2025 - Alkermes plc (Nasdaq: ALKS) ("Alkermes") and Avadel Pharmaceuticals plc (Nasdaq: AVDL) ("Avadel")

today announced that the companies have reached agreement on the terms of an increased recommended offer under which Alkermes will acquire

Avadel (the "Acquisition") for total transaction consideration of up to $22.50 per share, consisting of $21.00 in cash

and one (1) non-transferable contingent value right ("CVR") entitling holders to a potential additional cash payment

of $1.50 per share, contingent upon final U.S. Food and Drug Administration ("FDA") LUMRYZ Approval

(as defined in the form of CVR agreement to be entered into by Alkermes and the rights agent) for the treatment of idiopathic hypersomnia

in adults by the end of 2028 (the "Increased Offer"). In connection with the Increased Offer, Alkermes and Avadel

have entered into an amendment, dated November 18, 2025 (the "Amendment"), to the definitive transaction agreement

between the parties (the "Transaction Agreement" and, as amended, the "Amended Agreement") previously entered

into and announced on October 22, 2025 (the "October 2.7 Announcement").

The Increased Offer values Avadel at up to approximately

$2.37 billion, assuming the Milestone Payment (as defined in the revised offer announcement set out below) is made. The transaction, as

revised by the Increased Offer and the Amendment, has been approved by the boards of directors of Alkermes and Avadel and, subject to

the satisfaction of the Conditions (including the extended End Date as described in the revised offer announcement set out below), it

continues to be expected to close in the first quarter of 2026.

2025, Avadel announced that it had received an unsolicited proposal from H. Lundbeck A/S ("Lundbeck" and the "Lundbeck

Proposal") to acquire Avadel and that the Lundbeck Proposal was reasonably expected

to constitute a Company Superior Proposal (as such term is defined in the Transaction Agreement). On November 17, 2025, Avadel

further announced that the board of directors of Avadel had determined in good faith, after consultation with its financial and legal

advisors, that the Lundbeck Proposal constituted a "Company Superior Proposal" for the purposes of the Transaction Agreement.

Following this determination, Alkermes submitted the terms of its proposed Increased Offer to Avadel

on November 18, 2025.

assessing both the Lundbeck Proposal and Alkermes' Increased Offer and revised terms with

its outside legal counsel and financial advisors, the board of directors of Avadel has determined that the Lundbeck Proposal no

longer constitutes a "Company Superior Proposal" for the purposes of the Transaction Agreement. In

making this determination, the board of directors of Avadel determined that while the upfront cash consideration of $21.00 per

share in Alkermes' Increased Offer is identical to the cash consideration proposed in the Lundbeck Proposal, the terms of the CVR

in Alkermes' Increased Offer are superior to the terms of the CVR included in the Lundbeck Proposal, which was determined to be

unlikely to be achieved.

Alkermes and Avadel encourage their respective

shareholders to read the full text of the Amendment to be included with each company's current report on Form 8-K, which will

be filed with the United States Securities and Exchange Commission ("SEC") in due course and will be made available at https://www.alkermes.com/acquisition.

Further, Avadel intends to file a definitive proxy statement with the SEC related to the Acquisition. Shareholders are urged to read the

definitive proxy statement and such other relevant materials for more information. This summary should be read in conjunction with, and

is subject to, the full text of the revised offer announcement set out below, the Amendment, the Amended Agreement and the definitive

proxy statement (once filed). The Acquisition is subject to the conditions set out in Appendix III to the October 2.7 Announcement

(except that the End Date is extended as described in the revised offer announcement set out below) and the further terms set out in the

J.P. Morgan is acting as exclusive financial advisor

to Alkermes, and Paul, Weiss, Rifkind, Wharton & Garrison LLP and McCann FitzGerald LLP are acting as legal counsel to Alkermes

for the transaction. J.P. Morgan has provided fully committed financing to Alkermes in support of the transaction. Cleary Gottlieb Steen &

Hamilton LLP is acting as legal counsel to Alkermes for the financing. Morgan Stanley and Goldman Sachs are acting as financial advisors

to Avadel, and Goodwin Procter LLP and Arthur Cox LLP are acting as legal counsel to Avadel.

Alkermes plc (Nasdaq: ALKS), a mid-cap growth

and value equity, is a global biopharmaceutical company that seeks to develop innovative medicines in the field of neuroscience. Alkermes

has a portfolio of proprietary commercial products for the treatment of alcohol dependence, opioid dependence, schizophrenia and bipolar

I disorder, and a pipeline of clinical and preclinical candidates in development for neurological disorders, including narcolepsy and

idiopathic hypersomnia. Headquartered in Ireland, Alkermes also has a corporate office and research and development center in Massachusetts

and a manufacturing facility in Ohio. For more information, please visit Alkermes' website at www.alkermes.com.

About Avadel Pharmaceuticals plc

Avadel Pharmaceuticals plc (Nasdaq: AVDL) is a

biopharmaceutical company focused on transforming medicines to transform lives. Avadel's approach includes applying innovative solutions

to the development of medications that address the challenges patients face with current treatment options. Avadel's commercial

product, LUMRYZ , was approved by the U.S. Food & Drug Administration (FDA) as the first and only once-at-bedtime oxybate

for extended-release oral suspension for the treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years and older

with narcolepsy. For more information, please visit Avadel's website at www.avadel.com.

The release, publication or distribution of this

announcement in or into jurisdictions other than Ireland and the United States may be restricted by Law and therefore any persons who

are subject to the Law of any jurisdiction other than Ireland and the United States should inform themselves about, and observe, any applicable

legal or regulatory requirements. In particular, the ability of persons who are not resident in Ireland or the United States, to vote

their Avadel shares with respect to the Scheme at the Scheme Meeting, or to appoint another person as proxy to vote at the Scheme Meeting

on their behalf, may be affected by the Laws of the relevant jurisdictions in which they are located. Any failure to comply with the applicable

legal or regulatory requirements may constitute a violation of the Laws of any such jurisdiction. To the fullest extent permitted by applicable

Law, the Alkermes and Avadel persons involved in the proposed transaction disclaim any responsibility or liability for the violation of

such restrictions by any person.

This announcement has been prepared for the purpose

of complying with the Laws of Ireland and the Irish Takeover Rules, 2022 (the "Takeover Rules") and the information

disclosed herein may not be the same as that which would have been disclosed if this announcement had been prepared in accordance with

the Laws of jurisdictions outside of Ireland.

Participants in the Solicitation

Avadel and certain of its directors, executive

officers and employees may be deemed to be participants in the solicitation of proxies from Avadel shareholders in connection with the

transaction and any other matters to be voted on at the Scheme Meeting or the EGM. Information about the directors and executive officers

of Avadel, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in Avadel's

preliminary proxy statement on Schedule 14A for the proposed Acquisition, dated and filed with the SEC on November 13, 2025. Other

information regarding the persons who may, under the rules of the SEC, be deemed to be participants in the solicitation of Avadel

shareholders, including a description of their direct or indirect interests, by security holdings or otherwise, will be set forth in the

definitive Proxy Statement (which will contain the Scheme Document) and other relevant materials to be filed with the SEC in connection

with the Acquisition. You may obtain free copies of these documents using the sources indicated above.

No Offer or Solicitation

This announcement is for information purposes

only and is not intended to and does not constitute, or form part of, an offer, invitation or the solicitation of an offer or invitation

to purchase, otherwise acquire, subscribe for, sell or otherwise dispose of any securities, or the solicitation of any vote or approval

in any jurisdiction, pursuant to the transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any

jurisdiction in contravention of applicable Law.

The transaction will be implemented by means of

a High Court of Ireland sanctioned scheme of arrangement on the terms provided for in the scheme document (or, if the transaction is implemented

by way of a takeover offer, the takeover offer document), which will contain the full terms and conditions of the transaction, including

details of how Avadel's shareholders may vote in respect of the transactions contemplated by the Amended Agreement, including the

Acquisition. Any decision in respect of, or other response to, the proposed transaction, should be made only on the basis of the information

contained in the scheme document (or if the transaction is implemented by way of a takeover offer, the takeover offer document).

Important Additional Information

the proposed Acquisition, Avadel filed with the SEC on November 13, 2025 a preliminary Proxy Statement relating to the Scheme Meeting

and the EGM, which includes a draft of the Scheme Document. Avadel intends to file with the SEC a definitive Proxy Statement, which will

be sent to Avadel's shareholders as of the record date(s) to be established for voting at the Scheme Meeting and EGM. This