Cabaletta Bio, Inc.

Our named executive officers for the year ended December 31, 2024 are:

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Steven Nichtberger, M.D., our President and Chief Executive Officer;

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Gwendolyn Binder, Ph.D., our President, Science and Technology; and

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David J. Chang, M.D., M.P.H., our Chief Medical Officer.

2024 Summary Compensation Table

The following table presents the compensation awarded to, earned by or paid to each of our named executive officers for the years indicated. Dr. Nichtberger also serves as a member of our board of directors but does not receive any additional compensation for his service as a director.

(1) Amounts reflect the grant date fair value of option awards granted in 2024 and 2023 in accordance with the Financial Accounting Standards Board’s Accounting Standards Codification Topic 718, or ASC 718. Such grant date fair value does not take into account any estimated forfeitures related to service-vesting conditions. For information regarding assumptions underlying the valuation of equity awards, see Note 10 to our financial statements for the year ended December 31, 2024. These amounts do not correspond to the actual value that may be recognized by the named executive officers upon vesting of applicable awards.

(2) The amounts represent bonuses earned in 2024 and 2023 and paid in 2025 and 2024, respectively, pursuant to the Company’s cash incentive plan based on the factors described under “Non-Equity Incentive Plan Compensation” below.

(3) Amount includes reimbursements for life insurance premiums.

Narrative to 2024 Summary Compensation Table

Our board of directors and compensation committee review compensation annually for our chief executive officer and his direct reports. In setting executive base salaries and bonuses, and granting equity incentive awards, our board of directors considers compensation for comparable positions in the market, the historical compensation levels of our executives, individual performance as compared to our expectations and objectives, our desire to motivate our employees to achieve short-and long-term results that are in the best interests of our stockholders, and a long-term commitment to our company. We target a general competitive position, based on independent third-party benchmark analytics to inform the mix of compensation of base salary, bonus or long-term incentives.

Our board of directors has historically determined our executives’ compensation. Our compensation committee typically reviews and discusses management’s proposed compensation with the chief executive officer for all of his direct reports. Based on those discussions and its discretion, taking into account the factors noted above, the compensation committee determines the compensation for each executive officer other than the chief executive officer. Our board of directors discusses the compensation committee’s recommendations and ultimately approves the compensation of our chief executive officer without the chief executive officer and chief financial officer present. In 2024, the compensation committee continued to retain the services of Radford, an AON Hewitt company, as its external compensation consultant and the board of directors and the compensation committee considered Radford’s input on certain compensation matters as they deemed appropriate.

Annual base salary

Each named executive officer’s base salary is a fixed component of annual compensation for performing specific duties and functions, and has been established by our board of directors taking into account each individual’s role, responsibilities, skills, and experience. Base salaries for our named executive officers are reviewed annually by our compensation committee, typically in connection with our annual performance review process, and adjusted from time to time, based on the recommendation of the compensation committee, to realign salaries with market levels after taking into account individual responsibilities, performance, and experience. The base salary of each named executive officer in 2024 is noted below:

Non-Equity Incentive Plan Compensation

Annual cash awards are determined based on company performance, which is assessed based on predetermined annual objectives, and on individual performance. When determining the individual component of our annual incentive awards, the compensation committee considers each executive’s contributions to the company’s strategic achievements and financial and operational performance. In addition, the compensation committee considers how each executive demonstrates Cabaletta behaviors.

Each of our named executive officers was eligible to receive a bonus with respect to 2024 as a percentage of base salary listed below, modified by company and individual performance.

Company performance was assessed as achievement of 2024 company objectives, including certain clinical development, business development and financial and operational goals and development of a strong team culture. As a result, the compensation committee recommended and our board of directors approved 2024 company achievement at 108%.

The compensation committee recommended (and/or approved) and the board of directors approved (as applicable, in the instance of the chief executive officer), a further adjustment of bonuses based on the individual achievement of each of the named executive officers, as noted below:

Long-term equity incentives

Our equity grant program is intended to align the interests of our named executive officers with those of our stockholders and to motivate them to make important contributions to our performance. In 2024, we granted stock options to each of our named executive officers, as reflected in the “Outstanding Equity Awards at 2024 Fiscal Year End Table” below.

Employment arrangements with our named executive officers

In October 2019, we entered into amended and restated employment agreements with each of our named executive officers. Each of our named executive officers is employed at will.

Steven Nichtberger, M.D.

Under his amended and restated employment agreement, Dr. Nichtberger is entitled to an annual base salary, which is subject to review and redetermination by our board of directors or our compensation committee, and he is eligible to receive an annual bonus determined by our board of directors or the compensation committee (subject to the terms of any applicable incentive compensation plan that may be in effect from time to time), with a target amount calculated as a percentage of his annual base salary. Dr.

Nichtberger is also eligible to participate in the employee benefit plans available to our employees, subject to the terms of those plans, and is reimbursed for his existing, personal life insurance policy premiums.

Dr. Nichtberger’s employment agreement provides that, in the event that his employment is terminated by us without “cause” or by him for “good reason,” then subject to the execution and effectiveness of a separation agreement and release and compliance with his continuing obligations, he will be entitled to receive (i) an amount equal to (x) 12 months of base salary payable on our normal payroll cycle if such termination occurs outside of the period commencing 60 days before and ending 12 months after the occurrence of the first event constituting a “change in control”, or the Change in Control Period, or (y) 1.5 times the sum of his base salary plus his target bonus for the then-current year payable on our or our successor’s normal payroll cycle over 18 months if such termination occurs within Change in Control Period; (ii) payment of the monthly employer COBRA premium for the same level of group health coverage as in effect for Dr. Nichtberger on the date of termination for up to (x) 12 months if such termination occurs outside of the Change in Control Period, and (y) 18 months if such termination occurs within the Change in Control Period; and (iii) full acceleration of all stock options and other stock-based awards held by Dr. Nichtberger if such termination occurs within the Change in Control Period. In addition to standard good reason triggers, Dr. Nichtberger may elect to resign for good reason if within six months following the appointment of a chairperson of the board of directors, Dr. Nichtberger provides written notice of his reasonable dissatisfaction with such chairperson and the board fails to designate a new chairperson within 30 days of such notice. In the event of such a resignation for good reason outside of the Change in Control Period, subject to the execution and effectiveness of a separation agreement and release and compliance with his continuing obligations, in addition to the severance benefits described above, all stock options and other stock-based awards held by Dr. Nichtberger will accelerate and become fully exercisable or nonforfeitable.

The payments and benefits provided to Dr. Nichtberger under his employment agreement in connection with a sale event may not be eligible for a federal income tax deduction for the company pursuant to Section 280G of the Code. These payments and benefits also may be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Nichtberger in connection with a sale event would be subject to the excise tax on golden parachutes imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after tax benefit to Dr. Nichtberger.

In addition, Dr. Nichtberger has entered into a non-competition, non-solicitation, confidentiality and assignment agreement with us that contains, among other things, non-competition and non-solicitation provisions that apply during the term of Dr. Nichtberger’s employment and for 12 months thereafter.

Gwendolyn K. Binder, Ph.D.

Under her amended and restated employment agreement, Dr. Binder is entitled to an annual base salary, which is subject to review and redetermination by our board of directors or our compensation committee, and she is eligible to earn an annual bonus with a target amount calculated as a percentage of her base salary. Dr. Binder is also eligible to participate in the employee benefit plans available to our employees, subject to the terms of those plans.

Dr. Binder’s employment agreement provides that, in the event that her employment is terminated by us without “cause” or by her for “good reason,” then subject to the execution and effectiveness of a separation agreement and release and compliance with her continuing obligations, she will be entitled to receive (i) an amount equal to (x) nine months of base salary payable on our normal payroll cycle if such termination occurs outside of the Change in Control Period or (y) a lump sum in cash in the amount of 1.0 times the sum of her base salary plus her target bonus for the then-current year payable on our or our successor’s normal payroll cycle over 12 months if such termination is occurs within the Change in Control Period; (ii) payment of the monthly employer COBRA premium for the same level of group health coverage as in effect for Dr. Binder on the date of termination up to (x) nine months if such termination occurs outside of the Change in Control Period, and (y) 12 months if such termination occurs within the Change in Control Period; and (iii) full acceleration of all stock options and other stock-based awards subject to time-based vesting held by Dr. Binder if such termination occurs within the Change in Control Period.

The payments and benefits provided to Dr. Binder under her employment agreement in connection with a sale event may not be eligible for a federal income tax deduction for the company pursuant to Section 280G of the Code. These payments and benefits also may be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Binder in connection with a sale event would be subject to the excise tax on golden parachutes imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after-tax benefit to such officer.

In addition, Dr. Binder has entered into a non-competition, non-solicitation, confidentiality and assignment agreement with us that contains, among other things, non-competition and non-solicitation provisions that apply during the term of Dr. Binder’s employment and for 12 months thereafter.

David J. Chang, M.D., M.P.H.

Under his amended and restated employment agreement, Dr. Chang is entitled to an annual base salary, which is subject to review and redetermination by our board of directors or our compensation committee, and he is eligible to earn an annual bonus with a target amount calculated as a percentage of his base salary. Dr. Chang is also eligible to participate in the employee benefit plans available to our employees, subject to the terms of those plans.

Dr. Chang’s employment agreement provides that, in the event that his employment is terminated by us without “cause” or by him for “good reason,” then subject to the execution and effectiveness of a separation agreement and release and compliance with his continuing obligations, he will be entitled to receive (i) an amount equal to (x) nine months of base salary payable on our normal payroll cycle if such termination occurs outside of the Change in Control Period or (y) a lump sum in cash in the amount of 1.0 times the sum of his base salary plus his target bonus for the then-current year payable on our or our successor’s normal payroll cycle over 12 months if such termination occurs within the Change in Control Period; (ii) payment of the monthly employer COBRA premium for the same level of group health coverage as in effect for Dr. Chang on the date of termination up to (x) nine months if such termination occurs outside of the Change in Control Period, and (y) 12 months if such termination occurs outside of the Change in Control Period; and (iii) full acceleration of all stock options and other stock-based awards subject to time-based vesting held by Dr. Chang if such termination occurs within the Change in Control Period.

The payments and benefits provided to Dr. Chang under his employment agreement in connection with a sale event may not be eligible for a federal income tax deduction for the company pursuant to Section 280G of the Code. These payments and benefits also may be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Chang in connection with a sale event would be subject to the excise tax on golden parachutes imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after-tax benefit to such officer.

In addition, Dr. Chang has entered into a non-competition, non-solicitation, confidentiality and assignment agreement with us that contains, among other things, non-competition and non-solicitation provisions that apply during the term of Dr. Chang’s employment and for 12 months thereafter.

Outstanding Equity Awards at 2024 Fiscal Year End Table

The following table presents information regarding all outstanding stock awards and stock options held by each of our named executive officers as of December 31, 2024.

(1) These options vest over four years, with 25% vesting on October 11, 2019, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to a continued service relationship with us.

(2) These options vest over four years, with 25% vesting on October 24, 2020, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(3) These options vest over four years, with 25% vesting on March 1, 2021, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(4) These options vest over four years, with 25% vesting on October 11, 2019 and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(5) These options vest over four years, with 25% vesting on August 22, 2020, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(6) These options vest over four years, with 25% vesting on June 17, 2020, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(7) These options vest over four years, with 25% vesting on March 1, 2022, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(8) These options vest over four years, with 25% vesting on January 18, 2023, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(9) These options vest over four years, with 25% vesting on January 18, 2024, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

(10) These options vest over four years, with 25% vesting on March 1, 2025, and the remaining shares vesting in 12 equal quarterly installments thereafter, subject to a continued service relationship with us.

Additional Narrative Disclosure

401(k) Savings Plan. We participate in a retirement savings plan, or 401(k) plan, that is intended to qualify for favorable tax treatment under Section 401(a) of the Code, and contains a cash or deferred feature that is intended to meet the requirements of Section 401(k) of the Code. U.S. employees who are at least 21 years of age are generally eligible to participate in the 401(k) plan, subject to certain criteria. Participants may make pre-tax and certain after-tax (Roth) salary deferral contributions to the plan from their eligible earnings up to the statutorily prescribed annual limit under the Code. Participants who are 50 years of age or older may contribute additional amounts based on the statutory limits for catch-up contributions. Participant contributions are held in trust as required by law. An employee’s interest in his or her salary deferral contributions is 100% vested when contributed. We have the ability to make discretionary contributions under the plan and all eligible employees will receive a Safe Harbor matching contribution up to 4% of eligible pay for the 2024 plan year.

Health and Welfare Benefits. All of our full-time employees, including our executive officers are eligible to participate in certain medical, disability and life insurance benefit programs offered by us. We pay the premiums for term life insurance and long-term disability for all of our employees, including our executive officers. We also provide all employees, including executive officers, with a flexible spending account plan and paid time off benefits including, vacation, sick time and holidays. We do not sponsor any qualified or non-qualified defined benefit plans for any of our employees or executives.

Compensation Risk Assessment

We believe that although a portion of the compensation provided to our executive officers and other employees is performance-based, our executive compensation program does not encourage excessive or unnecessary risk taking. Our compensation programs are designed to encourage our executive officers and other employees to remain focused on both short-term and long-term strategic goals, in particular in connection with our pay-for-performance compensation philosophy. As a result, we do not believe that our compensation programs are reasonably likely to have a material adverse effect on us.

Policy on Trading, Pledging and Hedging of Company Stock

Certain transactions in our securities (such as purchases and sales of publicly traded put and call options, and short sales) create a heightened compliance risk or could create the appearance of misalignment between management and stockholders. In addition, securities held in a margin account or pledged as collateral may be sold without consent if the owner fails to meet a margin call or defaults on the loan, thus creating the risk that a sale may occur at a time when an officer or director is aware of material, non-public information or otherwise is not permitted to trade in Company securities. Our insider trading policy expressly prohibits short sales and derivative transactions of our stock by our executive officers, directors, employees and certain designated consultants and contractors, including short sales of our securities. Our insider trading policy expressly prohibits, without the advance approval of our audit committee, purchases or sales of puts, calls, or other derivative securities of the company or any derivative securities that provide the economic equivalent of ownership.

Compensation Recovery Policy (Clawback Policy)

On September 12, 2023, we adopted a Compensation Recovery Policy, or the Clawback Policy, in compliance with the requirements of the Dodd-Frank Act, final SEC rules and applicable Nasdaq listing standards (the “final clawback rules”), which covers our current and former executive officers, including all of our named executive officers. Under the Clawback Policy, in the event that we are required to prepare a restatement of our previously issued financial statements due to our material noncompliance with any financial reporting requirement under securities laws, we are required to recover (subject to certain limited exceptions described in the Clawback Policy and permitted under the final clawback rules) any cash or equity incentive-based compensation received by any current or former executive officer after the effective date of the Clawback Policy and in the three years prior to the date we are required to restate our financial statements that is in excess of the amount that would have been received based on the restated financial statements.

Compensation Committee Interlocks and Insider Participation

Each of Richard Henriques, Mark Simon and Shawn Tomasello, served on the compensation committee during fiscal year 2024. No member of the compensation committee has ever been an officer or employee of the Company. None of our executive officers serve, or have served during the last fiscal year, as a member of the board of directors, compensation committee, or other board committee performing equivalent functions of any other entity that has one or more executive officers serving as one of our directors or on our compensation committee.

Policy on the Timing of Awards of Options and Other Option-Like Instruments

Our compensation committee has generally granted annual equity awards, including stock option grants to our named executive officers, in the first quarter of each fiscal year, specifically early March. In addition, new hires receive stock option grants at the time of their hiring. Eligible employees, including our named executive officers, may voluntarily enroll in our Employee Stock Purchase Plan and receive an option to purchase shares at a discount using payroll deductions accumulated during the prior six months, with purchase dates occurring in May and November. During 2024, our compensation committee did not take into account any material nonpublic information when determining the timing and terms of equity incentive awards, andwe did not time the disclosure of material nonpublic information for the purpose of affecting the value of executive compensation. During 2024, we did not grant stock options to our named executive officers during any period beginning four business days before and ending one business day after the filing or furnishing of a Form 10-Q, 10-K or 8-K that discloses material nonpublic information.

Please see Item 10 for details regarding corporate governance, including the composition of our compensation committee, as required by Regulation S-K 407(e)(4) and (e)(5).

Director Compensation

The following table presents the total compensation for each person who served as a non-employee member of our board of directors and received compensation for such service during the fiscal year ended December 31, 2024. Other than as set forth in the table and described more fully below, we did not pay any compensation, make any equity awards or non-equity awards to, or pay any other compensation to any of the non-employee members of our board of directors in 2024. We reimburse members of our board of directors for reasonable travel expenses. Dr. Nichtberger, our Chief Executive Officer and President, did not receive any compensation for his service as a member and Chairman of our board of directors in 2024. Dr. Nichtberger’s compensation for service as an employee for fiscal years 2024 and 2023 is presented in “Executive Compensation—2024 Summary Compensation Table.”

(1) Amount shown reflects the grant date fair value of an option award granted during 2024. The grant date fair value was computed in accordance with Financial Accounting Standards Board Accounting Standards Codification Topic 718, Compensation—Stock Compensation, or FASB ASC Topic 718, disregarding the effect of estimated forfeitures related to service-based vesting. See Note 10 to the financial statements in our 2024 Annual Report on Form 10-K regarding assumptions we made in determining the fair value of option awards.

(2) As of December 31, 2024, the aggregate number of shares subject to option awards held by our non-employee directors were: Dr. Bollard: 134,428; Dr. Brun: 110,000; Mr. Henriques: 134,428; Mr. Simon: 134,428 and Ms. Tomasello 66,000. As of December 31, 2024, the aggregate number of unvested shares outstanding held by our non-employee directors were: Dr. Bollard: 22,000; Dr. Brun: 22,000; Mr. Henriques: 22,000; Mr. Simon: 22,000 and Ms. Tomasello 47,667.

Amended and Restated Non-Employee Director Compensation Policy

Under our director compensation policy, we pay our non-employee directors a cash retainer for service on the board of directors and for service on each committee on which the director is a member. The chairman of each committee receives a higher retainer for such service. These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment is prorated for any portion of such quarter that the director is not serving on our board of directors.

The fees paid to non-employee directors for service on the board of directors and for service on each committee of the board of directors on which the director is a member for 2024 are as follows:

In February 2025, we amended our director compensation policy. Accordingly, the fees paid to non-employee directors for service on the board of directors and for service on each committee of the board of directors on which the director is a member for 2025 are as follows:

We also reimburse our non-employee directors for reasonable out-of-pocket expenses incurred in connection with attending our board of director and committee meetings.

In addition, each new non-employee director elected to our board of directors will be granted an initial, one-time award of a stock option to purchase 44,000 shares, which shall vest in equal quarterly installments over a three-year period from the date of vesting commencement, subject to continued service as a director through each such vesting date. In addition, on the date of each annual meeting of stockholders of our company, each non-employee director will receive an annual stock option award of 22,000 shares, which shall vest in full upon the earlier to occur of the first anniversary of the date of grant or the date of the next annual meeting provided, however, that all vesting shall cease if the director resigns from the board of directors or otherwise ceases to serve as a director, unless the board of directors determines that the circumstances warrant continuation of vesting.

This program is intended to provide a total compensation package that enables us to attract and retain qualified and experienced individuals to serve as directors and to align our directors’ interests with those of our stockholders.