SC 13G/A

Name of reporting persons.

Boxer Capital, LLC

Check the appropriate box if a member of a group. (See instructions)

(a) ☐ (b) ☒

SEC use only.

Citizenship or place of organization.

Delaware

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Cabaletta Bio, Inc.

(Name of Issuer)

Common Stock, par value $0.00001

(Title of Class of Securities)

12674W109

(CUSIP Number)

February 13, 2020

(Date of Event which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

*	The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).


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CUSIP No. 12674W109

Based on 17,624,503 shares of voting common stock (“Common Stock”) outstanding and 24,034,022 shares of Common Stock and non-voting common stock (“Non-Voting Common Stock,” together with Common Stock, the “Combined Common Stock”) outstanding as of December 5, 2019, as set forth in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (“SEC”) on December 5, 2019. The Issuer’s final prospectus filed with the SEC on October 25, 2019 sets forth 6,409,519 shares of Non-Voting Common Stock.


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CUSIP No. 12674W109

Based on 17,624,503 shares of Common Stock outstanding and 24,034,022 shares of Combined Common Stock outstanding as of December 5, 2019, as set forth in the Issuer’s Quarterly Report on Form 10-Q filed with the SEC on December 5, 2019. The Issuer’s final prospectus filed with the SEC on October 25, 2019 sets forth 6,409,519 shares of Non-Voting Common Stock.


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CUSIP No. 12674W109

Based on 17,624,503 shares of Common Stock outstanding and 24,034,022 shares of Combined Common Stock outstanding as of December 5, 2019, as set forth in the Issuers Quarterly Report on Form 10-Q filed with the SEC on December 5, 2019. The Issuer’s final prospectus filed with the SEC on October 25, 2019 sets forth 6,409,519 shares of Non-Voting Common Stock.


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CUSIP No. 12674W109


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CUSIP No. 12674W109


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This Amendment No. 1 (“Amendment No. 1”) amends and supplements the statement on Schedule 13G initially filed on November 7, 2019 (the “Original Filing”) by Boxer Capital, LLC (“Boxer Capital”), Boxer Asset Management Inc. (“Boxer Management”), MVA Investors, LLC (“MVA Investors”) and Joe Lewis. This Amendment No. 1 serves as the original filing for Aaron I. Davis (“Aaron Davis” and, together with Boxer Capital, Boxer Management, Joe Lewis and MVA Investors, the “Reporting Persons”). The Original Filing remains in effect except to the extent that it is amended, restated or superseded by information contained in this Amendment No. 1. Capitalized terms used and not defined in this Amendment No. 1 have the meanings set forth in the Original Filing.

Item 1(a).

Name of Issuer:

Cabaletta Bio, Inc. (the “Issuer”)

Item 1(b).

Address of Issuer’s Principal Executive Offices:

2929 Arch Street, Suite 600

Philadelphia, PA 19104

Item 2(a).

Name of Person Filing:

This Schedule 13G is filed by the Reporting Persons. Boxer Management is the managing member and majority owner of Boxer Capital. Joe Lewis is the sole indirect beneficial owner of and controls Boxer Management. MVA Investors is the independent, personal investment vehicle of certain employees of Boxer Capital. Aaron Davis is a member of and has voting and dispositive power over securities held by MVA Investors.

Item 2(b).

Address of Principal Business Office, or, if none, Residence:

The principal business address of Boxer Capital, MVA Investors and Aaron Davis is: 11682 El Camino Real, Suite 320, San Diego, CA 92130. The principal business address of Boxer Management and Joe Lewis is: Cay House, EP Taylor Drive N7776, Lyford Cay, New Providence, Bahamas.

Item 2(c).

Citizenship:

Boxer Capital is a limited liability company organized under the laws of Delaware. Boxer Management is a corporation organized under the laws of the Bahamas. MVA Investors is a limited liability company organized under the laws of Delaware. Aaron Davis is a citizen of the United States. Joe Lewis is a citizen of the United Kingdom.

Item 2(d).

Title of Class of Securities:

Common stock, par value $0.00001 (the “Common Stock”)

Item 2(e).

CUSIP Number:

12674W109

Item 3.

If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), check whether the person filing is a:

Not applicable.


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Item 4.

Ownership.

(a)

Amount beneficially owned:

Boxer Capital, Boxer Management and Joe Lewis beneficially own 1,566,361 shares of Common Stock. MVA Investors and Aaron Davis beneficially own 89,414 shares of Common Stock. The Reporting Persons beneficially own, in the aggregate, 1,655,755 shares of Common Stock.

(b)

Percent of class:

The number of shares of Common Stock beneficially owned by Boxer Capital, Boxer Management and Joe Lewis represent 8.9% of the Issuer’s outstanding Common Stock and 6.5% of the Issuer’s outstanding Combined Common Stock. The number of shares of Common Stock beneficially owned by MVA Investors and Aaron Davis represent 0.5% of the Issuer’s outstanding Common Stock and 0.4% of the Issuer’s outstanding Combined Common Stock. The number of shares of Common Stock beneficially owned by the Reporting Persons represent, in the aggregate, 9.4% of the Issuer’s outstanding Common Stock and 6.9% of the Issuer’s outstanding Combined Common Stock. All percentages are based on 17,624,503 shares of Common Stock outstanding and 24,034,022 shares of Combined Common Stock outstanding as of December 5, 2019.

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or to direct the vote:

None of the Reporting Persons has sole power to vote or to direct the vote of any shares of Common Stock.

(ii)

Shared power to vote or to direct the vote:

Boxer Capital, Boxer Asset Management and Joe Lewis have shared power to vote or to direct the vote of the 1,566,361 shares of Common Stock they beneficially own. MVA Investors and Aaron Davis have shared power to vote or to direct the vote of the 89,414 shares of Common Stock they beneficially own.

(iii)

Sole power to dispose or to direct the disposition of:

None of the Reporting Persons has sole power to dispose or to direct the disposition of any shares of Common Stock.

(iv)

Shared power to dispose or to direct the disposition of:

Boxer Capital, Boxer Asset Management and Joe Lewis have shared power to dispose or to direct the disposition of the 1,566,361 shares of Common Stock they beneficially own. MVA Investors and Aaron Davis have shared power to dispose or to direct the disposition of the 89,414 shares of Common Stock they beneficially own.

Item 5.

Ownership of Five Percent or Less of a Class.

Not applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

Only Boxer Capital has the right to receive dividends and the proceeds from the sale of the shares of Common Stock held by Boxer Capital. Only MVA Investors has the right to receive dividends and the proceeds from the sale of the shares of Common Stock held by MVA Investors.


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Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not applicable.

Item 8.

Identification and Classification of Members of the Group.

Not applicable.

Item 9.

Notice of Dissolution of Group.

Not applicable.

Item 10.

Certification.

(c) By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

Exhibits



1		Joint Filing Agreement, dated February 14, 2020, among the Reporting Persons.


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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

February 14, 2020


BOXER CAPITAL, LLC

By:		/s/ Aaron I. Davis
Name:		Aaron I. Davis
Title:		Chief Executive Officer

BOXER ASSET MANAGEMENT INC.

By:		/s/ Jason Callender
Name:		Jason Callender
Title:		Director



JOSEPH C. LEWIS

/s/ Joseph C. Lewis
Joseph C. Lewis, Individually



MVA INVESTORS, LLC

By:		/s/ Aaron I. Davis
Name:		Aaron I. Davis
Title:		Authorized Signatory



AARON I. DAVIS

/s/ Aaron I. Davis
Aaron I. Davis, Individually