AVISTA HEALTHCARE PUBLIC ACQUISITION CORP. (NASDAQ:AHPA) Files An 8-K Entry into a Material Definitive Agreement
Item 1.01 Entry into a Material Definitive Agreement.

As previously disclosed, on August21, 2017, Avista Healthcare Public Acquisition Corp., a Cayman Islands exempted company (“AHPAC”), Avista Healthcare Merger Sub,Inc., a Delaware corporation and a direct wholly-owned subsidiary of AHPAC (“Merger Sub”), Avista Healthcare NewCo, LLC, a Delaware limited liability company and a direct wholly-owned subsidiary of AHPAC (“NewCo”), Envigo International Holdings,Inc., a Delaware corporation (“Envigo”) and Jermyn Street Associates, LLC, solely in its capacity as Shareholder Representative (as defined therein), entered into a Transaction Agreement (the “Transaction Agreement”).

On November22, 2017, to Section8.13 of the Transaction Agreement, AHPAC, Merger Sub, NewCo, the Shareholder Representative and Envigo entered into an amendment to the Transaction Agreement (the “Amendment”). The Amendment, among other things, amends the Termination Date (as defined in the Transaction Agreement) from January31, 2018 to March31, 2018. In addition, the Amendment provides that any notice of non-compliance received from NASDAQ by AHPAC, to the extent related to AHPAC’s failure to hold an annual meeting in 2017, shall not result in a failure of AHPAC to satisfy the conditions to Envigo’s consummation of the Business Combination (as defined in the Transaction Agreement).

Other than as modified to the Amendment, the Transaction Agreement remains in full force and effect. The foregoing descriptions of the Amendment and the Transaction Agreement do not purport to be complete and are qualified in their entirety by reference to the full text of the Amendment, a copy of which is filed as Exhibit2.1 hereto and the terms of which are incorporated herein by reference, and of the Transaction Agreement, a copy of which was filed as Exhibit2.1 to the Current Report on Form8-K filed with the U.S. Securities and Exchange Commission (the “SEC”) by AHPAC on August22, 2017, and is incorporated herein by reference.

Disclaimer

This Current Report shall neither constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which the offer, solicitation, or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction. This Current Report relates to a proposed Business Combination between AHPAC and Envigo.

Additional Information About the Business Combination

In connection with the proposed Business Combination between Envigo and AHPAC, AHPAC filed with the SEC a preliminary proxy statement and will file with the SEC and mail a definitive proxy statement and other relevant documentation to AHPAC’s shareholders. AHPAC’s shareholders and other interested persons are advised to read the preliminary proxy statement and the amendments thereto and the definitive proxy statement and documents incorporated by reference therein as these materials will contain important information about AHPAC, Envigo and the Business Combination. The definitive proxy statement will be mailed to AHPAC’s shareholders as of a record date to be established for voting on the proposed Business Combination when it becomes available. Shareholders may obtain a copy of the preliminary proxy, and will also be able to obtain a copy of the definitive proxy statement once it is available, without charge, at the SEC’s website at http://www.sec.gov or by directing a request to: Avista Healthcare Public Acquisition Corp., 65 East 55th Street, 18th Floor, New York, NY 10022.

Participants in the Solicitation

AHPAC and its directors, executive officers and other members of its management and employees may be deemed to be participants in the solicitation of proxies from AHPAC’s shareholders in connection with the proposed Business Combination. Shareholders are urged to carefully read the preliminary proxy statement filed with the SEC, and the definitive proxy statement regarding the proposed Business Combination when it becomes available, which contain important information. Information regarding the persons who may, under the rulesof the SEC, be deemed participants in the solicitation of AHPAC’s shareholders in connection with the proposed Business Combination are included in the preliminary proxy statement, and will be set forth in the definitive proxy statement when it is filed with the SEC. Information about AHPAC’s executive officers and directors also are included in the preliminary proxy statement and will be set forth in the definitive proxy statement relating to the proposed Business Combination when it becomes available.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits