1. Basis of Presentation

Cabaletta Bio, Inc. (the Company or Cabaletta) was incorporated in April 2017 in the State of Delaware as Tycho Therapeutics, Inc. and, in August 2018, changed its name to Cabaletta Bio, Inc. The Company is headquartered in Pennsylvania. Cabaletta is a clinical-stage biotechnology company focused on the discovery and development of engineered T cell therapies for B cell-mediated autoimmune diseases.

Principal operations commenced in April 2018, when the Company executed two sponsored research agreements with the Trustees of the University of Pennsylvania (Penn).

On October 16, 2019, the Company effected a 1-for-1.5 reverse split of the Company’s issued and outstanding shares of common stock, par value $0.00001 per share (Common Stock). Upon the effectiveness of the reverse stock split: (i) all shares of outstanding Common Stock were adjusted; (ii) the conversion price of the Series A convertible preferred stock (Series A Preferred), Series A-1 convertible preferred stock (Series A-1 Preferred), Series A-2 convertible preferred stock (Series A-2 Preferred) and Series B convertible preferred stock (Series B Preferred; collectively, the Preferred Shares) was adjusted; (iii) the number of shares of Common Stock for which each outstanding option to purchase Common Stock is exercisable was adjusted; and (iv) the exercise price of each outstanding option to purchase Common Stock was adjusted. All of the outstanding Common Stock share numbers (including shares of Common Stock subject to the Company’s options and as converted for the outstanding convertible preferred stock shares), share prices, exercise prices and per share amounts contained in the financial statements have been retroactively adjusted in the financial statements to reflect this reverse stock split for all periods presented. The par value per share and the authorized number of shares of Common Stock and convertible preferred stock were not adjusted as a result of the reverse stock split.

On October 29, 2019, the Company completed its initial public offering (IPO) of 6,800,000 shares of Common Stock at an offering price of $11.00 per share. The Company received net proceeds of $66,156 after deducting underwriting discounts, commissions and estimated offering expenses. In connection with the IPO, the Company’s outstanding shares of convertible preferred stock were automatically converted into 12,904,534 shares of Common Stock. In November 2019, the underwriters partially exercised their option and purchased an additional 475,501 shares of Common Stock resulting in net proceeds to the Company of $4,864, after deducting underwriting discounts and commissions.

Risks and Uncertainties

The Company does not expect to generate revenue from sales of engineered T cell therapies for B cell-mediated autoimmune diseases or any other revenue unless and until the Company completes preclinical and clinical development and obtains regulatory approval for one or more product candidates. If the Company seeks to obtain regulatory approval for any of its product candidates, the Company expects to incur significant commercialization expenses.

The Company has sustained annual operating losses and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities. The Company had cash and cash equivalents of $136,204 as of December 31, 2019. Through December 31, 2019, the Company has incurred an accumulated deficit of $32,959. Management expects to incur additional losses in the future as it continues its research and development and will need to raise additional capital to fully implement its business plan and to fund its operations.

The Company intends to raise such additional capital through a combination of equity offerings, debt financings, government funding arrangements, strategic alliances or other sources. However, if such financing is not available at adequate levels and on a timely basis, or such agreements are not available on favorable terms, or at all, as and when needed, the Company will need to reevaluate its operating plan and may be required to delay or discontinue the development of one or more of its product candidates or operational initiatives. The Company expects that its cash and cash equivalents as of December 31, 2019, will be sufficient to fund its projected operations for at least 12 months following the date of these financial statements.

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. As a result, the Company is unable to predict the timing or amount of increased expenses or when or if the Company will be able to achieve or maintain profitability. Further, the Company is currently dependent on Penn for much of its preclinical research, clinical research and development activities and expects to be dependent upon Penn for initial manufacturing activities (Note 7). Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. Even if the Company is able to generate revenues from the sale of its product candidates, if approved, it may not become profitable. If the Company fails to become profitable or is unable to sustain profitability on a continuing basis, then it may be unable to continue its operations at planned levels and be forced to reduce its operations.