AVISTA HEALTHCARE PUBLIC ACQUISITION CORP. (NASDAQ:AHPA) Files An 8-K Regulation FD Disclosure

AVISTA HEALTHCARE PUBLIC ACQUISITION CORP. (NASDAQ:AHPA) Files An 8-K Regulation FD DisclosureItem 9.01 Regulation FD Disclosure.

On August21, 2017, Avista Healthcare Public Acquisition Corp. (“AHPAC”) issued a press release (the “Press Release”) announcing the execution of a Transaction Agreement, by and among AHPAC, Avista Healthcare Merger Sub,Inc., a Delaware corporation and direct wholly-owned subsidiary of AHPAC, Avista Healthcare NewCo, LLC, a Delaware limited liability company and direct wholly-owned subsidiary of AHPAC, Envigo International Holdings,Inc., a Delaware corporation (“Envigo”), and Jermyn Street Associates, LLC, solely in its capacity as Shareholder Representative (as defined therein). The Transaction Agreement provides for the business combination (the “Business Combination”) of AHPAC and Envigo resulting in AHPAC becoming the ultimate parent company to Envigo and Envigo’s direct and indirect subsidiaries.

The Press Release is attached hereto as Exhibit99.1 and incorporated by reference herein.

Attached as Exhibit99.2 and incorporated by reference herein is an investor presentation dated August2017, that will be used by AHPAC with respect to the Business Combination.

The information in this Item 9.01, including Exhibit99.1 and Exhibit99.2, is furnished and shall not be deemed “filed” for purposes of Section18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to liabilities under that section, and shall not be deemed to be incorporated by reference into the filings of AHPAC under the Securities Act or the Exchange Act, regardless of any general incorporation language in such filings. This Current Report will not be deemed an admission as to the materiality of any information of the information in this Item 9.01, including Exhibit99.1 and Exhibit99.2.

Additional Information About the Business Combination

In connection with the proposed Business Combination between Envigo and AHPAC, AHPAC intends to file with the Securities and Exchange Commission (“SEC”) a preliminary and definitive proxy statement and will mail a definitive proxy statement and other relevant documentation to AHPAC’s shareholders. AHPAC’s shareholders and other interested persons are advised to read, when available, 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 will also be able to obtain a copy of the preliminary and definitive proxy statement once it is available, without charge, at the SEC’s website at http://sec.gov or by directing a request to: Avista Healthcare Public Acquisition Corp., 65 East 55th Street, 18th Floor, New York, NY 10022.

AHPAC shareholders will be able to obtain free copies of these documents (if and when available) and other documents containing important information about AHPAC and Envigo, once such documents are filed with the SEC.

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 proxy statement regarding the proposed Business Combination when it becomes available, because it will 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 will be set forth in the proxy statement when it is filed with the SEC. Information about AHPAC’s executive officers and directors also will be set forth in the proxy statement relating to the proposed Business Combination when it becomes available.

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.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits