UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): February 3, 2021

JAZZ PHARMACEUTICALS PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code 011-353-1-634-7800

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

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

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).

On February 3, 2021, Jazz Pharmaceuticals Public Limited Company, an Irish public limited company (“Jazz”), entered into a Transaction Agreement (“Transaction Agreement”) with GW Pharmaceuticals plc, a public limited company incorporated under the laws of England and Wales (“GW”) and Jazz Pharmaceuticals UK Holdings Limited, a private limited company incorporated under the laws of England and Wales and a wholly owned subsidiary of Jazz (“Bidco”), pursuant to which Bidco will acquire the entire issued share capital of GW pursuant to a scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006. A copy of the joint press release by Jazz and GW announcing the Transaction Agreement is attached as Exhibit 99.1 hereto and is incorporated herein by reference. Additional details regarding the terms of the Transaction Agreement will be filed with the Securities and Exchange Commission (the “SEC”) separately.

(d) Exhibits

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Additional Information and Where to Find It

In connection with the proposed transaction, GW Pharmaceuticals intends to file a proxy statement with the SEC. Each of Jazz Pharmaceuticals and GW Pharmaceuticals may also file other relevant documents with the SEC regarding the proposed transaction. The definitive proxy statement (if and when available) will be mailed to shareholders of GW Pharmaceuticals. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE PROXY STATEMENT (WHICH WILL INCLUDE AN EXPLANATORY STATEMENT IN RESPECT OF THE SCHEME OF ARRANGEMENT OF GW PHARMACEUTICALS, IN ACCORDANCE WITH THE REQUIREMENTS OF THE U.K. COMPANIES ACT 2006) AND ANY OTHER RELEVANT DOCUMENTS THAT MAY BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

Investors and security holders will be able to obtain free copies of the proxy statement (if and when available) and other documents containing important information about Jazz Pharmaceuticals, GW Pharmaceuticals and the proposed transaction, once such documents are filed with the SEC through the website maintained by the SEC at http://www.sec.gov. Copies of the documents filed with the SEC by Jazz Pharmaceuticals will be available free of charge on Jazz Pharmaceuticals’ website at https://www.jazzpharma.com. Copies of the documents filed with the SEC by GW Pharmaceuticals will be available free of charge on GW Pharmaceuticals’ website at https://www.gwpharm.com.

Participants in the Solicitation

Jazz Pharmaceuticals, GW Pharmaceuticals, their respective directors and certain of their executive officers and other employees may be deemed to be participants in the solicitation of proxies from GW Pharmaceuticals’ security holders in connection with the proposed transaction. Information about GW Pharmaceuticals’ directors and executive officers is set forth in GW Pharmaceuticals’ proxy statement on Schedule 14A for its 2020 Annual General Meeting, which was filed with the SEC on April 7, 2020, and its Current Report on Form 8-K filed with the SEC on September 10, 2020 and subsequent statements of beneficial ownership on file with the SEC. Information about Jazz

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Pharmaceuticals’ directors and executive officers is set forth in Jazz Pharmaceuticals’ proxy statement on Schedule 14A for its 2020 Annual General Meeting, which was filed with the SEC on June 12, 2020 and subsequent statements of beneficial ownership on file with the SEC. Additional information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of GW Pharmaceuticals security holders in connection with the proposed transaction, including a description of their direct or indirect interests, by security holdings or otherwise, will be set forth in the proxy statement when it is filed with the SEC.

No Offer or Solicitation

This communication is not intended to and shall not constitute an offer to buy or sell or the solicitation of an offer to buy or sell any securities, or a solicitation of any vote or approval, nor shall there be any offer, solicitation or sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made in the United States absent registration under the U.S. Securities Act of 1933, as amended (Securities Act), or pursuant to an exemption from, or in a transaction not subject to, such registration requirements. The Jazz Pharmaceuticals securities issued in the proposed transaction are anticipated to be issued in reliance upon an available exemption from such registration requirements pursuant to Section 3(a)(10) of the Securities Act.

Forward Looking Statements

This communication contains forward-looking statements regarding Jazz Pharmaceuticals and GW Pharmaceuticals, including, but not limited to, statements related to the proposed acquisition of GW Pharmaceuticals and the anticipated timing, results and benefits thereof, including the potential for Jazz Pharmaceuticals to accelerate its growth and neuroscience leadership, and for the acquisition to provide long-term growth opportunities to create shareholder value; Jazz Pharmaceuticals’ expected financing for the transaction; and other statements that are not historical facts. You can generally identify forward-looking statements by the use of forward-looking terminology such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “explore,” “evaluate,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” or “will,” or the negative thereof or other variations thereon or comparable terminology. These forward-looking statements are based on each of the companies’ current plans, objectives, estimates, expectations and intentions and inherently involve significant risks and uncertainties, many of which are beyond Jazz Pharmaceuticals’ or GW Pharmaceuticals’ control. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks and uncertainties associated with: Jazz Pharmaceuticals’ and GW Pharmaceuticals’ ability to complete the acquisition on the proposed terms or on the anticipated timeline, or at all, including risks and uncertainties related to securing the necessary regulatory and shareholder approvals, the sanction of the High Court of Justice of England and Wales and satisfaction of other closing conditions to consummate the acquisition; the occurrence of any event, change or other circumstance that could give rise to the termination of the definitive transaction agreement relating to the proposed transaction; risks related to diverting the attention of GW Pharmaceuticals and Jazz Pharmaceuticals management from ongoing business operations; failure to realize the expected benefits of the acquisition; significant transaction costs and/or unknown or inestimable liabilities; the risk of shareholder litigation in connection with the proposed transaction, including resulting expense or delay; the risk that GW Pharmaceuticals’ business will not be integrated successfully or that such integration may be more difficult, time-consuming or costly than expected; Jazz Pharmaceuticals’ ability to obtain the expected financing to consummate the acquisition; risks related to future opportunities and plans for the combined company, including the uncertainty of expected future regulatory filings, financial performance and results of the combined company following completion of the acquisition; GW Pharmaceuticals’ dependence on the successful commercialization of Epidiolex/Epidyolex and the uncertain market potential of Epidiolex; pharmaceutical product development and the uncertainty of clinical success; the regulatory approval process, including the risks that GW Pharmaceuticals may be unable to submit anticipated regulatory filings on the timeframe anticipated, or at all, or that GW Pharmaceuticals may be unable to obtain regulatory approvals of any of its product candidates, including nabiximols and Epidiolex for additional indications, in a timely manner or at all; disruption from the proposed acquisition, making it more difficult to conduct business as usual or maintain relationships with customers, employees or suppliers; effects relating to the announcement of the acquisition or any further announcements or the consummation of the acquisition on the market price of Jazz Pharmaceuticals’ ordinary shares or GW Pharmaceuticals’ American depositary shares or ordinary shares; the possibility that, if Jazz Pharmaceuticals does not achieve the perceived benefits of the acquisition as rapidly or to the extent anticipated by financial analysts or

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investors, the market price of Jazz Pharmaceuticals’ ordinary shares could decline; potential litigation associated with the possible acquisition; regulatory initiatives and changes in tax laws; market volatility; and other risks and uncertainties affecting Jazz Pharmaceuticals and GW Pharmaceuticals, including those described from time to time under the caption “Risk Factors” and elsewhere in Jazz Pharmaceuticals’ and GW Pharmaceuticals’ Securities and Exchange Commission (SEC) filings and reports, including Jazz Pharmaceuticals’ Annual Report on Form 10-K for the year ended December 31, 2019 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, GW Pharmaceuticals’ Annual Report on Form 10-K for the year ended December 31, 2019 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, and future filings and reports by either company. In addition, while Jazz Pharmaceuticals and GW Pharmaceuticals expect the COVID-19 pandemic to continue to adversely affect their respective business operations and financial results, the extent of the impact on the combined company’s ability to generate sales of and revenues from its approved products, execute on new product launches, its clinical development and regulatory efforts, its corporate development objectives and the value of and market for its ordinary shares, will depend on future developments that are highly uncertain and cannot be predicted with confidence at this time. Moreover, other risks and uncertainties of which Jazz Pharmaceuticals or GW Pharmaceuticals are not currently aware may also affect each of the companies’ forward-looking statements and may cause actual results and the timing of events to differ materially from those anticipated. Investors are cautioned that forward-looking statements are not guarantees of future performance. The forward-looking statements made in this communication are made only as of the date hereof or as of the dates indicated in the forward-looking statements and reflect the views stated therein with respect to future events as at such dates, even if they are subsequently made available by Jazz Pharmaceuticals or GW Pharmaceuticals on their respective websites or otherwise. Neither Jazz Pharmaceuticals nor GW Pharmaceuticals undertakes any obligation to update or supplement any forward-looking statements to reflect actual results, new information, future events, changes in its expectations or other circumstances that exist after the date as of which the forward-looking statements were made.

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SIGNATURES

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