[8-K] Cabaletta Bio, Inc. Reports Material Event

Rhea-AI Filing Summary

Cabaletta Bio reported an administrative update. The company filed an 8-K stating it posted an updated corporate presentation on October 29, 2025, available on the Investors & Media section of its website. The presentation is attached as Exhibit 99.1 and incorporated by reference. The filing is presented under Item 8.01 (Other Events) with related exhibits listed under Item 9.01(d).

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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 29, 2025

CABALETTA BIO, INC.

(Exact name of Registrant as Specified in Its Charter)

Delaware			001-39103	82-1685768
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
2929 Arch Street Suite 600
Philadelphia, Pennsylvania				19104
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: (267) 759-3100

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:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐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, par value $0.00001 per share		CABA		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 ☐

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. ☐

Item 8.01 Other Events.

On October 29, 2025, Cabaletta Bio, Inc. (the “Company”) posted to the “Investors & Media” section of the Company’s website at www.cabalettabio.coman updated corporate presentation (the “Corporate Presentation”). A copy of the Corporate Presentation is attached hereto as Exhibit 99.1 and is incorporated by reference into this Item 8.01 of this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

99.1		Cabaletta Bio, Inc. Corporate Presentation, dated October 2025.
104		Cover Page Interactive Data File (embedded within the Inline XBRL Document).

SIGNATURE

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.

		CABALETTA BIO, INC.
Date: October 29, 2025		By:	/s/ Steven Nichtberger
			Steven Nichtberger
			Chief Executive Officer and President (Principal Executive Officer)

FAQ

What did Cabaletta Bio (CABA) announce in this 8-K?

The company posted an updated corporate presentation and furnished it as Exhibit 99.1.

Where can investors access Cabaletta Bio’s updated presentation?

It is posted on the company’s website in the Investors & Media section and attached as Exhibit 99.1.

When was the presentation posted or dated?

The update was posted on October 29, 2025, and the presentation is dated October 2025.

Which items are covered in the 8-K?

The update is under Item 8.01 (Other Events), with exhibits listed under Item 9.01(d).

What exhibit contains the corporate presentation for Cabaletta Bio (CABA)?

The corporate presentation is attached as Exhibit 99.1.

What is Cabaletta Bio’s trading symbol and exchange?

The trading symbol is CABA on The Nasdaq Global Select Market.