New York, NY and Canton, MA, Avista Healthcare Public Acquisition Corp. (NASDAQ: AHPA) ("AHPAC"), a publicly traded special purpose acquisition company, and Organogenesis Inc. ("Organogenesis" or the "Company"), a leading regenerative medicine company focused on the development, manufacture and commercialization of product solutions for the Advanced Wound Care, Surgical and Sports Medicine markets, today announced that they have entered into a definitive merger agreement, under which Organogenesis will become a wholly owned subsidiary of AHPAC. Affiliates of Avista Capital Partners ("Avista"), a leading private equity firm, have agreed to invest $92 million in the combined company in conjunction with the transaction. Following the closing of the transaction, Organogenesis will be listed on the Nasdaq Stock Exchange under the ticker symbol "ORGO." The combined company will have an anticipated initial enterprise value of approximately $673 million. Organogenesis' mission is to provide integrated healing solutions that substantially improve medical outcomes and the lives of patients, while lowering the overall cost of care. Organogenesis' versatile product portfolio is designed to treat a variety of patients with repair and regenerative needs across the continuum of care. Today, Organogenesis has over 600 employees worldwide and is led by a management team of talented individuals with more than 75 years of collective regenerative medicine experience. "We are delighted to be partnering with Organogenesis, as the Company is well-positioned to benefit from secular tailwinds driving growth in the Advanced Wound Care, Surgical and Sports Medicine sectors," said Thompson Dean, Executive Chairman of AHPAC. "Organogenesis represents an ideal partner for AHPAC given its leading position in the large and attractive regenerative medicine sector, numerous growth opportunities and demonstrated ability to execute on product development and commercialization capabilities." Gary S. Gillheeney, Sr., President and Chief Executive Officer of Organogenesis, said "This is an important day in the history of Organogenesis. We look forward to working with Tom Dean, AHPAC and Avista Capital Partners to continue building a successful enterprise. This transaction will provide Organogenesis with capital that we will use to accelerate our growth plan for both our existing product portfolio and R&D pipeline."

Additional Transaction Terms and Conditions

This transaction will be funded through a combination of cash, stock, and rollover debt financing. Organogenesis? key existing shareholders will remain committed long-term partners by rolling over their equity into the combined company. The boards of directors of AHPAC and the Company have unanimously approved the proposed transaction and shareholders of the Company representing approximately 89% of the outstanding stock of the Company have agreed to support approval of the proposed transaction in any consent solicitation or shareholders? meeting in connection with the transaction. Completion of the proposed transaction, which is expected before the end of the year, is subject to customary and other closing conditions, including regulatory approvals and receipt of approvals from AHPAC?s shareholders. Credit Suisse Securities (USA) LLC is acting as financial advisor to AHPAC. Weil, Gotshal & Manges LLP is acting as legal advisor to AHPAC. Foley Hoag LLP is acting as legal advisor to Organogenesis.

Investor Presentation Information

AHPAC and Organogenesis are simultaneously releasing a slide presentation with information on the proposed transaction; this presentation will be filed with the Securities and Exchange Commission (SEC) as an exhibit to AHPAC?s Form 8-K, which will be filed to report its entry into the merger agreement, and can be viewed on the SEC website at www.sec.gov. Investors are encouraged to review these materials.

About Organogenesis Inc.

Organogenesis Inc. is a leading regenerative medicine company offering a portfolio of bioactive and acellular biomaterials products in advanced wound care and surgical biologics, including orthopaedics and spine. Organogenesis's comprehensive portfolio is designed to treat a variety of patients with repair and regenerative needs. For more information, visit?www.organogenesis.com.

About Avista Healthcare Public Acquisition Corp.

AHPAC is a special purpose acquisition company that completed its initial public offering in October 2016. AHPAC was formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization, or business combination with one or more businesses. AHPAC is sponsored by Avista Acquisition Corp., which was formed for the express purpose of acting as the sponsor for AHPAC. Avista Acquisition Corp. is an affiliate of Avista Capital Holdings, L.P. For more information, visit .?www.avistapac.com/ahpac.

About Avista Capital Partners

Founded in 2005, Avista is a leading New York-based private equity firm with over $6 billion invested in more than 30 growth-oriented healthcare businesses. Avista targets businesses with strong management teams, stable cash flows and robust growth prospects and utilizes a proactive, hands-on approach to create value in our portfolio companies. Avista?s Operating Executives and Advisors are an integral part of the team, providing strategic insight, operational oversight and senior counsel, that help drive growth and performance to create long-term value and sustainable businesses. For more information, visit?www.avistacap.com.

Contacts:

Kekst (for AHPAC and Avista Capital Partners) Daniel Yunger 212-521-4800 daniel.yunger@kekst.com Angelyn Lowe 781-774-9364 alowe@organo.com posed business combination when it becomes available.