Obsidian Therapeutics, Inc.

As filed with the Securities and Exchange Commission on August 28, 2026.

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

Delaware

(State or other jurisdiction of incorporation or organization)

(Primary Standard Industrial Classification Code Number)

42-1977778

(I.R.S. Employer Identification Number)

1030 Massachusetts Avenue

Cambridge,

MA

(

)

806-6245

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Madan Jagasia

Chief Executive Officer

Massachusetts Avenue

Cambridge,

MA

(

)

806-6245

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate Date of Commencement of Proposed Sale to the Public:

From time to time after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a

non-accelerated

filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule

12b-2

of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.☐

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

On August 3, 2026, or the Closing Date, Obsidian Therapeutics, Inc., a Delaware corporation (formerly known as Gazelle Parent, Inc.), or the Parent (also referred to herein as “we” or “us”), completed the previously announced Mergers (as defined below) pursuant to the Agreement and Plan of Merger, dated April 14, 2026, or the Merger Agreement, by and among Parent, Obsidian Therapeutics Sub, Inc., a Delaware corporation, (formerly known as Obsidian Therapeutics, Inc., or Legacy Obsidian), Onyx MergerSub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of Parent, or Obsidian Merger Sub, Galera Therapeutics, Inc., a Delaware corporation, or Legacy Galera, and Gazelle Merger Subsidiary, Inc., a Delaware corporation and a direct, wholly owned subsidiary of Parent, or Galera Merger Sub. On the Closing Date, pursuant to the Merger Agreement and on the terms and conditions set forth therein, each pursuant to the provisions of the General Corporation Law of the State of Delaware, as amended, or the DGCL, (a) Obsidian Merger Sub merged with and into Legacy Obsidian, with Legacy Obsidian as the surviving entity, which transaction is referred to herein as the “Obsidian Merger,” and (b) immediately following the Obsidian Merger, Galera Merger Sub merged with and into Legacy Galera, with Legacy Galera as the surviving entity, which transaction is referred to herein as the “Galera Merger,” and together with the Obsidian Merger, referred to herein as the “Mergers.”

Concurrently with entering into the Merger Agreement, on April 14, 2026, Legacy Obsidian and Legacy Galera entered into a securities purchase agreement, or the Securities Purchase Agreement, with certain qualified institutional buyers and/or accredited investors, or the Investors. Pursuant to the Securities Purchase Agreement, and subject to the terms and conditions therein, the Investors agreed to purchase, and Legacy Galera agreed to issue and sell, immediately prior to the effective time of the Obsidian Merger, or the Obsidian Effective Time, shares of Legacy Galera’s Series CNon-Voting Convertible Preferred Stock, par value $0.001 per share, or Series C Preferred Stock, for an aggregate purchase price of $350.0 million, or the PIPE Financing. On the Closing Date, each outstanding share of Legacy Galera common stock (including those resulting from the conversion of the preferred stock andpre-funded warrants, but excluding dissenting shares and certain excluded shares as described in the prospectus filed by the Parent on July 2, 2026) was converted into the right to receive a number of shares of common stock of Parent, par value $0.0001 per share, or Parent Common Stock, calculated as described in the prospectus filed by the Parent on July 2, 2026.

Our common stock began trading on the Nasdaq Capital Market, or Nasdaq, under the symbol “OBX” on August 4, 2026.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any state or jurisdiction where the offer or sale is not permitted.

Subject to Completion, Dated August 28, 2026

PRELIMINARY PROSPECTUS

29,164,045 Shares of Common Stock

This prospectus relates to the proposed offer and resale or other disposition from time to time by the selling stockholders identified in this prospectus of up to an aggregate of 29,164,045 shares of our common stock, par value $0.0001 per share.

We are registering the resale of the shares of common stock pursuant to the selling stockholders’ registration rights under a registration rights agreement between us and the selling stockholders. Our registration of the resale of the shares of common stock covered by this prospectus does not mean that the selling stockholders will offer or sell all or any of the shares of common stock. The selling stockholders may offer, sell or distribute all or a portion of their shares of common stock from time to time directly or indirectly through one or more underwriters, broker-dealers or agents, and in one or more public or private transactions. The shares of common stock may be sold in one or more transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale or at negotiated prices. These sales may be effected in transactions, which may involve crosses or block transactions. See the section titled “Plan of Distribution” for more information.

We will not receive any proceeds from any sale of common stock by the selling stockholders pursuant to this prospectus. We have agreed to bear the expenses in connection with the registration of the resale of the shares of common stock to be offered by this prospectus by the selling stockholders other than any underwriting discounts and commissions or transfer taxes relating to the sale of common stock, which will be borne by the selling stockholders.

Our common stock is listed on Nasdaq under the symbol “OBX.” On August 27, 2026, the closing price for our common stock, as reported on Nasdaq, was $17.04 per share.

See the section titled “Risk Factors” beginning on page 9 of this prospectus to read about factors you should consider before buying our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is , 2026.