Obsidian leverages their cytoDRIVE platform to
develop engineered TIL cell therapies. OBX-115 is currently in a Phase 2 clinical trial for the treatment of advanced melanoma and a Phase 1 clinical trial for the treatment of NSCLC. OBX-115 is designed with regulatable membrane-bound IL15 (mbIL15), which drives TIL persistence, eliminates the need to dose toxic interleukin-2 (IL2), and enables outpatient
administration of low-dose lymphodepletion. Furthermore, OBX-115 can be manufactured using tumor tissue procurement from an outpatient, minimally invasive core needle
biopsy. OBX-115 has been granted Fast Track and Regenerative Medicine Advanced Therapy designations from the U.S. Food and Drug Administration for the treatment of patients with unresectable or metastatic
melanoma that is resistant to immune checkpoint inhibitor therapy.
“We believe this transaction with Obsidian is the best path forward for Galera
and look forward to the combined company’s success,” said J. Mel Sorensen, M.D., Chief Executive Officer of Galera. “Obsidian’s pipeline of novel engineered TIL cell therapies and its promising lead product candidate, OBX-115, offer near-term, value creating milestones for Galera stockholders. In addition, Galera stockholders will retain a contingent value right for 95% of all future milestones for up to 10 years arising out of
its October 2025 Asset Purchase Agreement with Biossil.ai for its dismutase mimetics.”
About the Proposed Transaction
Under the terms of the merger agreement, as of the closing of the proposed transaction, the pre-closing Galera
stockholders (other than those investors participating in the private placement financing) are expected to own approximately 1.8% of the combined company, the pre-closing Obsidian stockholders are expected to
own approximately 53.2% of the combined company, and investors in the private placement financing are expected to own approximately 45.0% of the combined company. The percentage of the combined company that Galera’s stockholders will own as of
the closing of the proposed transaction is subject to adjustment based on the estimated amount of Galera’s net cash immediately prior to the closing date.
The pre-closing Galera stockholders (other than those investors participating in the private placement financing) are
expected to receive one contingent value right for each outstanding share of Galera common stock held by such stockholder, representing the right to receive contingent payments upon the occurrence of certain events (including receipt of milestone
proceeds under the Biossil.ai agreement).
The transaction has received approval by the Board of Directors of both companies and is expected to close by
the third quarter of 2026, subject to certain closing conditions, including, among others, approval by the stockholders of each company, the effectiveness of a registration statement to be filed with the U.S. Securities and Exchange Commission (the
“SEC”) to register the securities to be issued in connection with the proposed acquisitions of Obsidian and Galera and the satisfaction of other customary closing conditions.
The combined company plans to operate under the name Obsidian Therapeutics, Inc. and will be led by Madan Jagasia, M.D., Obsidian’s current Chief
Executive Officer. Obsidian’s Board of Directors will become directors of the combined company, chaired by Maria Fardis, Ph.D., M.B.A., Chief Executive Officer of AirNexis Therapeutics.
Leerink Partners is serving as exclusive financial advisor and Goodwin Procter LLP is serving as legal counsel to Obsidian. Leerink Partners, TD Cowen, Piper
Sandler, William Blair and LifeSci Capital are acting as placement agents in connection with the concurrent private placement financing. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. is serving as legal counsel to the placement agents. Sidley
Austin LLP is serving as legal counsel to Galera. Lucid Capital Markets is providing a fairness opinion to Galera’s Board of Directors.
About
Obsidian Therapeutics
Obsidian Therapeutics, Inc. is a clinical-stage biopharmaceutical company harnessing novel protein-regulation technology to
develop engineered TIL cell therapies for the treatment of patients with solid tumors. Obsidian’s proprietary cytoDRiVE platform is highly versatile and allows us to leverage drug
responsive domains, or DRDs, to control protein function, with our initial focus on TIL cell therapies developed from this platform, or cytoTILs. Obsidian is headquartered in Cambridge, MA.
For more information, please visitwww.obsidiantx.com .
About Galera Therapeutics
Galera Therapeutics, Inc. is a clinical-stage biopharmaceutical company focused on advancing a pan-NOS inhibitor
through clinical development for patients with the hardest-to-treat forms of advanced breast cancer. It was historically focused on developing avasopasem, a small
molecule dismutase mimetic, in combination with chemoradiotherapy, to reduce the toxicities of the conventional regimens in patients with head and neck cancer.
Additional Information and Where to Find It
In
connection with the proposed transactions between Obsidian and Galera, Galera and the newly-formed company will file relevant materials with the SEC. The newly-formed company will file a registration statement on Form
S-4 that will include a proxy statement or information statement and prospectus relating to the proposed transaction, which will constitute a proxy statement or information statement of Galera and a prospectus
of the newly-formed company (the “Prospectus”). Galera and the newly-formed company may also file other documents with the SEC regarding the proposed transaction. This document is not a substitute for the Prospectus or any other document
which Galera or the newly-formed company may file with the SEC or send to stockholders of Galera or Obsidian in connection with the proposed transaction. The Prospectus will be mailed to stockholders of Galera. INVESTORS AND SECURITYHOLDERS OF
GALERA ARE URGED TO READ THE REGISTRATION STATEMENT AND THE PROSPECTUS AND ALL OTHER DOCUMENTS FILED OR THAT WILL BE FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT GALERA, OBSIDIAN AND THE
PROPOSED TRANSACTION. Investors and security holders will be able to obtain free copies of the registration statement and the Prospectus (when available) and other documents filed with the SEC by Galera or the newly-formed company through the
website maintained by the SEC at www.sec.gov. Copies of the documents filed with the SEC by Galera will be available free of charge on Galera’s website at www.galeratx.com.
No Offer or Solicitation
This communication is for
informational purposes only and not intended to and does not constitute an offer to subscribe for, buy or sell, or the solicitation of an offer to subscribe for, buy or sell, or an invitation to subscribe for, buy or sell, any securities of Galera,
Obsidian or the newly-formed company, or the solicitation of any vote or approval in any jurisdiction pursuant to or in connection with the proposed transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any
jurisdiction in contravention of applicable law. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended, and otherwise in accordance with applicable
law.
Participants in the Solicitation
This
communication is not a solicitation of a proxy from any security holder of Galera or Obsidian. However, Galera and Obsidian and each of their respective directors and executive officers may be considered participants in the solicitation of proxies
in connection with the proposed transaction. Information about the directors and executive officers of Galera may be found in its Annual Report on Form 10-K for the year ended December 31, 2025, which was
filed with the SEC on March 19, 2026 and its proxy statement for its 2026 annual meeting of stockholders, which was filed with the SEC on April 10, 2026. Other information regarding the participants in the proxy solicitations and a
description of their direct and indirect interests, by security holdings or otherwise, will be contained in Prospectus and other relevant materials to be filed with the SEC when they become available.