Latham & Watkins Advises Boundless Bio on Merger With Serapha Bio

Boundless Bio, Inc. (Nasdaq: BOLD) and Serapha Bio, Inc., a privately held biotechnology company developing an investigational in vivo base editing therapy for Alpha‑1 Antitrypsin Deficiency (AATD), announced that they have entered into a definitive merger agreement pursuant to which Serapha will combine with Boundless Bio in an all‑stock merger. Prior to the closing, Boundless Bio expects to declare a cash dividend to pre‑merger Boundless stockholders. Upon completion of the transaction, the combined company plans to operate under the name Serapha Bio, Inc. and is expected to trade on Nasdaq under the ticker symbol AATD. In support of the proposed merger, Serapha has secured commitments for pre‑closing private investments of approximately US$230 million from a syndicate of investors co‑led by RA Capital Management and RTW Investments and including participation by Janus Henderson Investors, Decheng Capital, Vivo Capital, Casdin Capital, LifeSci Venture Partners, Logos Capital, Balyasny Asset Management, and Eventide Asset Management, of which approximately US$138 million has already been funded in a Series A financing. The additional US$92 million in funding is expected to close substantially concurrently with the merger, subject to customary closing conditions. The transaction has received unanimous approval by the Board of Directors of both companies and is expected to close in the fourth quarter of 2026, subject to certain closing conditions.

Latham & Watkins LLP represents Boundless Bio in the transaction with a corporate deal team led by partners Daniel Rees, Cheston Larson, Matt Bush, and Shannon Cheng, with associates Dylan Towns, Amy Lutfi, Ashley Campfield, Joanna Yam, and Emily Okabe. Advice was also provided on capital markets matters by associates Nadia Patiño, Shelby Harrison, and Sterling Swift; on FDA and healthcare regulatory matters by partner Betty Pang and counsel Chad Jennings, with associate Evan Miller; on intellectual property matters by partner Steven Chinowsky and counsel Robert Yeh, with associate Patrick Chew; on tax matters by partner Eric Cho, with associate Chris Zhao; on benefits and executive compensation matters by partners Holly Bauer and James Robinson, with associates Julie Voorhes and Genie Yae; on antitrust matters by partners Patrick English and Kyra Bromley, with associate Suhansi Perera; and on data privacy and cybersecurity matters by partner Heather Deixler, with associate Zac Alpert.