Exhibit 5.1
[Goodwin Procter LLP Letterhead]
December 12, 2022
Cabaletta Bio, Inc.
2929 Arch Street, Suite 600
Philadelphia, PA 19104
| | Re: | Securities Registered under Registration Statement on Form S-3 |
We have acted as counsel to you in connection with your filing of a Registration Statement on Form S-3 (File No. 333-250006) (as amended or supplemented, the “Registration Statement”) filed on November 10, 2020 with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration of the offer by Cabaletta Bio, Inc., a Delaware corporation (the “Company”) of up to $250,000,000 of any combination of securities of the types specified therein. The Registration Statement was declared effective by the Commission on November 18, 2020. Reference is made to our opinion letter dated November 10, 2020 and included as Exhibit 5.1 to the Registration Statement. We are delivering this supplemental opinion letter in connection with the prospectus supplement (the “Prospectus Supplement”) filed on December 8, 2022 by the Company with the Commission pursuant to Rule 424 under the Securities Act. The Prospectus Supplement relates to the offering by the Company of up to 6,340,591 shares of the Company’s Common Stock, par value $0.00001 per share (the “Common Stock”), consisting of (i) 126,815 shares of Common Stock (the “Shares”), and (ii) up to 6,213,776 shares of Common Stock issuable upon the exercise of pre-funded warrants (the “Pre-Funded Warrants” and the shares issuable upon exercise of the Pre-Funded Warrants, the “Pre-Funded Warrants Shares”), in each case covered by the Registration Statement. The Shares and the Pre-Funded Warrants are being sold to the several underwriters named in, and pursuant to, an underwriting agreement among the Company and such underwriters (the “Underwriting Agreement”).
We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinions set forth below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinions set forth below, on certificates of officers of the Company. For purposes of the opinion set forth in numbered paragraph 3, we have assumed that before the Pre-Funded Warrants Shares are issued, the Company does not issue shares of Common Stock or reduce the total number of shares of Common Stock that the Company is authorized to issue under its certificate of incorporation such that the number of unissued shares of Common Stock authorized under the Company’s certificate of incorporation is less than the number of Pre-Funded Warrants Shares.
The opinions set forth below are limited to the Delaware General Corporation Law.
