Cabaletta Bio, Inc.

For the period ended Jun 9, 2026. Filed Apr 28, 2026.

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What shareholders are asked to vote on at a company's meeting. It is where to find what directors and top executives are paid, and who owns the most shares.

Jun 9, 2026 · Filed Apr 28, 2026

CABA$1.30+1.6%Stored close · as of Nov 6, 2026

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.)

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐	Preliminary Proxy Statement

☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒	Definitive Proxy Statement

☐	Definitive Additional Materials

☐	Soliciting Material Pursuant to §240.14a-12

(Name of registrant as specified in its charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☒	No fee required.

☐	Fee paid previously with preliminary materials.

☐	Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

NOTICE OF 2026 ANNUAL MEETING OF STOCKHOLDERS

To be held June 9, 2026

Notice is hereby given that the 2026 Annual Meeting of Stockholders, or Annual Meeting, of Cabaletta Bio, Inc., will be held online on June 9, 2026 at 9:00 a.m. Eastern Time. This year’s Annual Meeting will be a virtual meeting, which will be conducted via live webcast. You may attend the meeting virtually via the Internet by registering at www.proxydocs.com/CABA, where you will be able to vote electronically and submit questions. You will need the control number included with the Notice of Internet Availability of Proxy Materials being mailed to you separately in order to attend the Annual Meeting. The purpose of the Annual Meeting is the following:

1.	To elect two class I directors to our board of directors, to serve until the 2029 annual meeting of stockholders and until their successor has been duly elected and qualified, or until their earlier death, resignation or removal;

2.	To ratify the appointment of Ernst & Young LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026;

3.	To approve Amendment No. 2 to the Cabaletta Bio, Inc. 2019 Stock Option and Incentive Plan (the “Plan Amendment Proposal”);

4.	To approve an amendment to our Third Amended and Restated Certificate of Incorporation to increase the number of authorized shares of common stock from 300,000,000 to 600,000,000 (the “Charter Amendment Proposal”);

5.	To approve, on a non-binding, advisory basis, the compensation of our named executive officers;

To approve a proposal to adjourn the Annual Meeting to a later date or dates, if necessary or appropriate, to permit further solicitation and vote of proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the Charter Amendment Proposal or the Plan Amendment Proposal (the “Adjournment Proposal”); and

7.	To transact any other business properly brought before the Annual Meeting or any adjournment or postponement of the Annual Meeting.

The proposal for the election of directors relates solely to the election of two class I directors nominated by the board of directors.

Only Cabaletta Bio, Inc. stockholders of record at the close of business on April 20, 2026, will be entitled to vote at the Annual Meeting and any adjournment or postponement thereof.

Cabaletta Bio, Inc. is following the Securities and Exchange Commission’s “Notice and Access” rule that allows companies to furnish their proxy materials by posting them on the Internet. As a result, we are mailing to our stockholders a Notice of Internet Availability of Proxy Materials, or the Notice, instead of a paper copy of the accompanying proxy statement and our Annual Report for the fiscal year ended December 31, 2025, or 2025 Annual Report. We plan to mail the Notice on or about April 28, 2026, and it contains instructions on how to access both the 2025 Annual Report and accompanying proxy statement over the Internet. This method provides our stockholders with expedited access to proxy materials and not only lowers the cost of printing and distribution but also reduces the environmental impact of the Annual Meeting. If you would like to receive a print version of the proxy materials, free of charge, please follow the instructions on the Notice.

To be admitted to the Annual Meeting and vote your shares, you must register in advance at www.proxydocs.com/CABA prior to the meeting and provide the control number as provided in the Notice, or proxy card, or voting instruction form at www.proxydocs.com/CABA. Upon completing your registration, you will receive further instructions via email, including unique links to access the Annual Meeting and to submit questions in advance of the Annual Meeting. Please see the “General Information” section of the proxy statement that accompanies this notice for more details regarding the logistics of the virtual Annual Meeting, including the ability of stockholders to submit questions during the Annual Meeting, and technical details and support related to accessing the virtual platform.

Your vote is important. Whether or not you expect to attend the virtual meeting, it is important that your shares be represented. To ensure that your vote is recorded promptly, please vote as soon as possible, even if you plan to attend the meeting, by submitting your proxy via the Internet at the address listed on the proxy card or by signing, dating and returning the proxy card. Even if you have voted by proxy, you may still vote at the virtual meeting.

Please note, however, that if your shares are held through a broker, bank or other nominee and you wish to vote at the meeting, you must obtain a proxy issued in your name from that record holder.

By order of the Board of Directors,

/s/ Steven Nichtberger

Steven Nichtberger, M.D.

President and Chief Executive Officer

Philadelphia, Pennsylvania

April 28, 2026

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The text of this filing, as the company filed it with the SEC, without its images or exhibits. This is not investment advice.