SEC FORM 3

SEC FORM 3SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Leoni Matthew James

(Last)

(First)

(Middle)

C/O KORSANA BIOSCIENCES, INC.

203 CRESCENT STREET, SUITE 503

(Street)

WALTHAM

MASSACHUSETTS

02453

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
09/08/2026

3. Issuer Name and Ticker or Trading Symbol
Korsana Biosciences, Inc. [ KRSA ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Chief Medical Officer

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock Option (Right to Buy)	⁽¹⁾⁽²⁾	06/07/2036	Common Stock	253,415	$7.48	D
Stock Option (Right to Buy)	⁽¹⁾⁽³⁾	06/29/2036	Common Stock	394,314	$8.06	D

Explanation of Responses:

1. Effective as of September 8, 2026 (the "Effective Time"), (i) Cariboos Merger Sub Corp., a wholly owned subsidiary of Cyclerion Therapeutics, Inc. ("Cyclerion"), merged with and into Korsana Biosciences, Inc. ("Pre-Merger Korsana"), with Pre-Merger Korsana continuing as a wholly owned subsidiary of Cyclerion and the surviving corporation of the merger (the "First Merger"), and (ii) immediately thereafter, Pre-Merger Korsana merged with and into Cariboos Merger Sub II, LLC, a second wholly owned subsidiary of Cyclerion ("Second Merger Sub"), with Second Merger Sub being the surviving entity of the merger under the name Korsana Biosciences Operating Company, LLC (the "Second Merger" and, together with the First Merger, the "Merger"). At the Effective Time, Cyclerion changed its name to "Korsana Biosciences, Inc." (hereinafter, the "Issuer").

2. Represents options to purchase shares of the Issuer's common stock received by the Reporting Person in the Merger in exchange for options of Pre-Merger Korsana held by the Reporting Person prior to the Merger. This option will vest as to 25% on June 8, 2027 and in equal monthly installments thereafter through June 8, 2030, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

3. Represents options to purchase shares of the Issuer's common stock received by the Reporting Person in the Merger in exchange for options of Pre-Merger Korsana held by the Reporting Person prior to the Merger. This option will vest as to 25% on June 18, 2027 and in equal monthly installments thereafter through June 18, 2030, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Mark Vignola, as attorney-in-fact for Matthew Leoni	09/10/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)