As filed with the Securities and Exchange Commission on September 23, 2026

Registration No. 333-   

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

CalciMedica, Inc.

(Exact name of registrant as specified in its charter)

2023 Equity Incentive Plan

2023 Employee Stock Purchase Plan

(Full titles of the plans)

A. Rachel Leheny, Ph.D.

Chief Executive Officer

505 Coast Boulevard South, Suite 300-9

La Jolla, California 92037

(858) 952-5500

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

Copies to:

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. ☐

REGISTRATION OF ADDITIONAL SHARES PURSUANT TO GENERAL INSTRUCTION E

This Registration Statement on Form S-8 is being filed by CalciMedica, Inc. (the “Registrant”) with the Securities and Exchange Commission (the “SEC”) for the purpose of increasing the number of securities of the same class as other securities for which a Registration Statement on Form S-8 relating to the same employee benefit plans is effective. The Registrant previously registered its shares of common stock, par value $0.0001 per share, for issuance under (i) the Registrant’s 2023 Employee Stock Purchase Plan under the Registrant’s Registration Statements on Form S-8 filed with the SEC on May 12, 2023 (File No. 333-271898), March 28, 2024 (File No. 333-278336) and June  24, 2025, as amended June 27, 2025 (File No. 333-288287) (collectively, the “Registration Statements”) and (ii) the Registrant’s Amended 2023 Equity Incentive Plan under the Registration Statements and the Registrant’s Registration Statement on Form S-8 filed with the SEC on August 27, 2024 (File No. 333-281800) (together with the Registration Statements, the “Prior Registration Statements”). On August 27, 2026 the Company effected a reverse stock split of its outstanding shares of Common Stock at a ratio of 1-for-5 (the “Reverse Stock Split”). The number of shares of Common Stock registered hereby gives effect to the Reverse Stock Split and the shares of Common Stock registered by the Prior Registration Statements have been automatically adjusted to give effect to the Reverse Stock Split; however such Prior Registration Statements and any documents incorporated by reference herein and therein, except as otherwise stated, have not been amended to reflect such automatic adjustment or the Reverse Stock Split. Pursuant to General Instruction E to Form S-8, this Registration Statement hereby incorporates by reference the contents of the Prior Registration Statements.

ITEM 8. EXHIBITS.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of La Jolla, State of California, on September 23, 2026.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints A. Rachel Leheny, Ph.D. and Stephen Bardin, and each of them, as true and lawful attorneys-in-fact and agents, with full powers of substitution and resubstitution, for them and in their name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, and generally to do all such things in their names and behalf in their capacities as officers and directors to enable CalciMedica, Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he might or could do in person, ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his substitutes or substitute, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement on Form S-8 has been signed by the following persons in the capacities and on the dates indicated.

Exhibit 5.1

Carlos Ramirez

T: +1 858 550 6157

cramirez@cooley.com

September 23, 2026

CalciMedica, Inc.

505 Coast Boulevard South, Suite 300-9

La Jolla, CA 92037

Ladies and Gentlemen:

We have acted as counsel to CalciMedica, Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a registration statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission (the “Commission”), covering the offering of up to 1,685,248 shares of the Company’s Common Stock, $0.0001 par value per share (the “Shares”), consisting of (i) 1,654,374 shares issuable pursuant to the Company’s 2023 Equity Incentive Plan, as amended (the “2023 Plan”), and (ii) 30,874 shares issuable pursuant to the Company’s 2023 Employee Stock Purchase Plan (together with the 2023 Plan, the “Plans”).

In connection with this opinion, we have examined and relied upon (i) the Registration Statement and related prospectuses, (ii) the Company’s certificate of incorporation and bylaws, each as currently in effect, (iii) the Plans, and (iv) such other records, documents, certificates, memoranda and instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures; the authenticity of all documents submitted to us as originals; the conformity to originals of all documents submitted to us as copies; the accuracy, completeness and authenticity of certificates of public officials; and the due authorization, execution and delivery of all documents by all persons other than by the Company. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans, the Registration Statement and related prospectuses, will be validly issued, fully paid and nonassessable (except as to Shares issued pursuant to deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

This opinion is limited to the matters expressly set forth in this letter, and no opinion has been or should be implied, or may be inferred, beyond the matters expressly stated. This opinion speaks only as to law and facts in effect or existing as of the date hereof, and we have no obligation or responsibility to update or supplement this opinion to reflect any facts or circumstances that may hereafter come to our attention or any changes in law that may hereafter occur.

We consent to the filing of this opinion as an exhibit to the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Commission thereunder.

Cooley LLP 10265 Science Center Drive San Diego, CA 92121

t: (858) 550-6000 f: (858) 550-6420 cooley.com

Page Two

Sincerely,

Cooley LLP

Cooley LLP 10265 Science Center Drive San Diego, CA 92121

t: (858) 550-6000 f: (858) 550-6420 cooley.com

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in this Registration Statement on Form S-8 of CalciMedica, Inc. (the “Company”) of our report dated March 3, 2026, relating to the consolidated financial statements of the Company (which report expresses an unqualified opinion and includes an explanatory paragraph relating to a going concern uncertainty), appearing in the Annual Report on Form 10-K of the Company for the year ended December 31, 2025, filed with the Securities and Exchange Commission.

/s/ Baker Tilly US, LLP

San Diego, California

September 23, 2026