Cabaletta Bio, Inc. — Major Shareholding Notification 2024

Feb 14, 2024

SC 13G/A 1 formsc13ga.htm

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Cabaletta Bio, Inc.

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(Name of Issuer)

Common Stock, par value $0.00001 per share

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(Title of Class of Securities)

12674W109

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(CUSIP Number)

December 31, 2023

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(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 SCHEDULE 13G

| 1 | NAME
OF REPORTING PERSONS Commodore
Capital LP |
| --- | --- |
| 2 | CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b)
☐ |
| 3 | SEC
USE ONLY |
| 4 | CITIZENSHIP
OR PLACE OF ORGANIZATION Delaware,
USA |

| NUMBER
OF SHARES BENEFICIALLY OWNED
BY EACH REPORTING PERSON WITH | SOLE
VOTING POWER 0 |
| --- | --- |
| 6 | SHARED
VOTING POWER 1,900,000 |
| 7 | SOLE
DISPOSITIVE POWER 0 |
| 8 | SHARED
DISPOSITIVE POWER 1,900,000 |

| 9 | AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,900,000 | |
| --- | --- | --- |
| 10 | CHECK
IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ☐ |
| 11 | PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 4.4% | |
| 12 | TYPE
OF REPORTING PERSON IA | |

*See Item 4 for additional information.

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CUSIP No. 12674W109 SCHEDULE 13G

| 1 | NAME
OF REPORTING PERSONS Commodore
Capital Master LP |
| --- | --- |
| 2 | CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b)
☐ |
| 3 | SEC
USE ONLY |
| 4 | CITIZENSHIP
OR PLACE OF ORGANIZATION Cayman
Islands |

| NUMBER
OF SHARES BENEFICIALLY OWNED
BY EACH REPORTING PERSON WITH | SOLE
VOTING POWER 0 |
| --- | --- |
| 6 | SHARED
VOTING POWER 1,900,000 |
| 7 | SOLE
DISPOSITIVE POWER 0 |
| 8 | SHARED
DISPOSITIVE POWER 1,900,000 |

| 9 | AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,900,000 | |
| --- | --- | --- |
| 10 | CHECK
IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES | ☐ |
| 11 | PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 4.4% | |
| 12 | TYPE
OF REPORTING PERSON OO | |

*See Item 4 for additional information.

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CUSIP No. 12674W109 SCHEDULE 13G

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, Pennsylvania 19104

| Item
2. |
| --- |
| This
report on Schedule 13G is being filed by Commodore Capital LP, a Delaware limited partnership (the “Firm”) and Commodore
Capital Master LP, a Cayman Islands exempted limited partnership (“Commodore Master”). The address for the Firm and Commodore
Master is: 444 Madison Avenue, Floor 35, New York, New York 10022. |

ITEM 2. (d) Title of Class of Securities

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

ITEM 2. (e) CUSIP No.:

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:

N/A

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CUSIP No. 12674W109 SCHEDULE 13G

ITEM 4. Ownership

As reported in the cover pages to this report, the ownership information with respect to the Firm is as follows:

(a) Amount Beneficially Owned: 1,900,000*

(b) Percent of Class: 4.4%*

(c) Number of Shares as to which such person has:

(i) Sole power to vote or to direct the vote: 0

(ii) Shared power to vote or to direct the vote: 1,900,000*

(iii) Sole power to dispose or to direct the disposition of: 0

(iv) Shared power to dispose or to direct the disposition of: 1,900,000*

As reported in the cover pages to this report, the ownership information with respect to Commodore Master is as follows:

(a) Amount Beneficially Owned: 1,900,000*

(b) Percent of Class: 4.4%*

(c) Number of Shares as to which such person has:

(i) Sole power to vote or to direct the vote: 0

(ii) Shared power to vote or to direct the vote: 1,900,000*

(iii) Sole power to dispose or to direct the disposition of: 0

(iv) Shared power to dispose or to direct the disposition of: 1,900,000*

*The Firm is the investment manager to Commodore Master. As of December 31, 2023, the Firm may be deemed to beneficially own an aggregate of 1,900,000 shares of Common Stock of the Issuer. The Firm, as the investment manager to Commodore Master, may be deemed to beneficially own these securities. Michael Kramarz and Robert Egen Atkinson are the managing partners of the Firm and exercise investment discretion with respect to these securities. Ownership percentages are based on 42,849,412 shares of Common Stock reported as issued and outstanding as of November 3, 2023 in the Issuer’s Form 10-Q, filed with the Securities and Exchange Commission on November 9, 2023.

| Item
5. |
| --- |
| If
this statement is being filed to report the fact that as of the date hereof the reporting
person has ceased to be the beneficial owner of more than five percent of the class of securities,
check the following [X]. |

ITEM 6. Ownership of More Than Five Percent on Behalf of Another Person

Not Applicable.

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.

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CUSIP No. 12674W109 SCHEDULE 13G

ITEM 8. Identification and Classification of Members of the Group

Not Applicable.

ITEM 9. Notice of Dissolution of Group

Not Applicable.

| Item
10. |
| --- |
| 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. |

Exhibit Index

1. Joint Filing Agreement dated as of January 13, 2023, by and between Commodore Capital LP and Commodore Capital Master LP (incorporated by reference to Exhibit 1 to the Schedule 13G filed with the Securities and Exchange Commission on January 13, 2023).

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CUSIP No. 12674W109 SCHEDULE 13G

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.

Dated: February 14, 2024

| Commodore
Capital LP | |
| --- | --- |
| By: | /s/
Michael Kramarz |
| Michael
Kramarz, Managing Partner | |
| Commodore
Capital Master LP | |
| By: | /s/
Michael Kramarz |
| Michael
Kramarz, Authorized Signatory | |

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