C4 Therapeutics posts Phase 1 data; terminates ATM prospectus

Rhea-AI Filing Summary

C4 Therapeutics, Inc. (CCCC) announced two updates. The company posted a presentation with data from its Phase 1 trial of cemsidomide plus dexamethasone in relapsed/refractory multiple myeloma, available on its investor relations site and filed as Exhibit 99.1.

The company also ended its current ATM prospectus. Effective October 16, 2025, the sales agreement prospectus dated November 13, 2024 was terminated. The underlying Sales Agreement with TD Securities (USA) LLC (TD Cowen) remains in effect, and no further common stock sales will be made under that prospectus unless a new prospectus supplement or a new registration statement with sales agreement prospectus is filed. As of June 30, 2025, the company had sold 3,769,483 shares under the Sales Agreement for gross proceeds of approximately $9.6 million before commissions.

Insights

Capital markets analyst

Administrative ATM reset; no ongoing share sales under old prospectus.

C4 Therapeutics terminated the dated ATM prospectus while keeping the Sales Agreement in place. This pauses additional sales under that document until a new prospectus supplement or registration statement is filed and used.

Previously, the company raised gross proceeds of $9.6M from 3,769,483 shares as of June 30, 2025. The update clarifies that further issuances under the prior prospectus will not occur.

The clinical data presentation for cemsidomide plus dexamethasone is made available via Exhibit 99.1. Actual impact will depend on future disclosures and any new prospectus or registration statement filed.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

_________________________________________________________________

FORM 8-K

_________________________________________________________________

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 16, 2025

_________________________________________________________________

C4 THERAPEUTICS, INC.

(Exact name of Registrant as Specified in Its Charter)

_________________________________________________________________

Delaware			001-39567			47-5617627
(State or Other Jurisdiction of Incorporation)			(Commission File Number)			(IRS Employer Identification No.)
490 Arsenal Way,   Suite 120 Watertown,  MA						02472
(Address of Principal Executive Offices)						(Zip Code)

Registrant’s Telephone Number, Including Area Code: (617) 231-0700

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

_________________________________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o			Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
o			Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
o			Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
o			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, $0.0001 par value per share

CCCC

The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company o

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 13(a) of the Exchange Act. o

Item 8.01 Other Events.

On October 16, 2025, C4 Therapeutics, Inc. (the “Company”) posted a presentation with data from its Phase 1 clinical trial of cemsidomide in combination with dexamethasone for the treatment of relapsed/refractory multiple myeloma. The presentation has been published to the “Events & Presentations” page of the investor relations section of the Company’s website and is for use in meetings with investors, analysts and others. The presentation is filed as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference.

Sales Agreement with TD Securities (USA) LLC

Effective October 16, 2025, the Company terminated the sales agreement prospectus, dated November 13, 2024, related to the sale of shares of the Company’s common stock, par value $0.001 per share (“Common Stock”), from time to time pursuant to the Sales Agreement, dated October 31, 2024, by and between TD Securities (USA) LLC (“TD Cowen”) and the Company (the “Sales Agreement”). As a result, the Company will not make any sales of Common Stock pursuant to the Sales Agreement, unless and until a new sales agreement prospectus supplement or a new registration statement with sales agreement prospectus is filed. The Sales Agreement remains in full force and effect. As of June 30, 2025, the Company had issued and sold 3,769,483 shares of its Common Stock under the Sales Agreement with TD Cowen for gross proceeds of approximately $9.6 million, before deducting commissions to TD Cowen.

A copy of the Sales Agreement was filed as Exhibit 1.2 to the Company’s Registration Statement on Form S-3 (File No. 333-282933), which was originally filed with the SEC on October 31, 2024, and declared effective on November 13, 2024.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits. The exhibits shall be deemed to be filed or furnished, depending on the relevant item requiring such exhibit, in accordance with the provisions of Item 601 of Regulation S-K (17 CFR 229.601) and Instruction B.2 to this form.

Exhibit Number						Description
99.1						Data presentation dated October 16, 2025
104						Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

			C4 Therapeutics, Inc.
Date: October 16, 2025			By:			/s/ Jolie M. Siegel
						Jolie M. Siegel
						Chief Legal Officer and Secretary

FAQ

What did C4 Therapeutics (CCCC) disclose in this update?

The company posted a Phase 1 data presentation (Exhibit 99.1) for cemsidomide plus dexamethasone and terminated its November 13, 2024 ATM prospectus.

Is the Sales Agreement with TD Securities (USA) LLC still active for CCCC?

Yes. The Sales Agreement remains in full force and effect, but no sales will occur under the terminated prospectus unless a new prospectus or registration is filed.

How much has C4 Therapeutics raised under the Sales Agreement to date?

As of June 30, 2025, it issued and sold 3,769,483 shares for gross proceeds of approximately $9.6 million before commissions.

What clinical program was highlighted in the new presentation?

Phase 1 data of cemsidomide in combination with dexamethasone for relapsed/refractory multiple myeloma.

Can CCCC sell more shares under its previous ATM prospectus?

No. The company will not make sales under that prospectus unless a new sales agreement prospectus supplement or a new registration statement is filed.