SEC 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

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1. Name and Address of Reporting Person* Meng Lei (Last) (First) (Middle) C/O DIANTHUS THERAPEUTICS, INC. 7 TIMES SQUARE, 43RD FLOOR (Street) NEW YORK NY 10036 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 09/11/2023	3. Issuer Name and Ticker or Trading Symbol Dianthus Therapeutics, Inc. /DE/ [ DNTH ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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)
Common Stock	1,217,554(1)(2)	I	See footnote(3)(4)

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)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Meng Lei (Last) (First) (Middle) C/O DIANTHUS THERAPEUTICS, INC. 7 TIMES SQUARE, 43RD FLOOR (Street) NEW YORK NY 10036 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Avidity Partners Management LP (Last) (First) (Middle) 2828 N HARWOOD STREET, SUITE 1220 (Street) DALLAS TX 75201 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Effective as of September 11, 2023 (the "Effective Time"), a wholly-owned subsidiary of Magenta Therapeutics, Inc. ("Magenta"), merged (the "Merger") with and into Dianthus Therapeutics, Inc. ("Dianthus") resulting in, among other things, Dianthus becoming a wholly owned subsidiary of Magenta. At the Effective Time, Magenta effected a name change to "Dianthus Therapeutics, Inc." (hereinafter, the "Issuer").

2. Represents the number of shares of common stock of the Issuer received by the Reporting Person in the Merger in exchange for the shares of Dianthus held by the Reporting Person prior to the Merger. Each share of Dianthus common stock held at the Effective Time was exchanged for 0.2181 shares of the Issuer's common stock, which gives effect to the reverse stock split of common stock effected by the Issuer and the Merger exchange ratio.

3. The reported shares are held by clients of Avidity Partners Management LP and may be deemed to beneficially owned by (i) Avidity Partners Management LP, (ii) Avidity Partners Management (GP) LLC, the general partner of Avidity Partners Management LP and (iii) each of David Witzke and Michael Gregory, the managing members of Avidity Partners Management (GP) LLC. Lei Meng, an employee of Avidity Partners Management LP, is a director of the Issuer. Avidity Partners Management LP, Avidity Partners Management (GP) LLC, Mr. Witzke and Mr. Gregory may be considered directors by deputization due to their affiliation with Ms. Meng. Each Reporting Person disclaims beneficial ownership of these shares except to the extent of its, his or her pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

4. As of the date hereof, Avidity Partners Management (GP) LLC, David Witzke and Michael Gregory have not yet received the applicable EDGAR codes required to make filings with the Securities and Exchange Commission; however, such Reporting Persons have applied for the applicable codes and will supplement this Form 3 once such codes are available.

Remarks:

Exhibit 24 - Power of Attorney

	MENG LEI /s/ Adam Veness, as attorney-in-fact for Lei Meng	09/13/2023
	AVIDITY PARTNERS MANAGEMENT LP By: Avidity Partners Management (GP) LLC, its general partner /s/ David Witzke Managing Member /s/ Michael Gregory Managing Member	09/13/2023
	AVIDITY PARTNERS MANAGEMENT (GP) LLC /s/ David Witzke Managing Member /s/ Michael Gregory Managing Member	09/13/2023
	DAVID WITZKE /s/ David Witzke	09/13/2023
	MICHAEL GREGORY /s/ Michael Gregory	09/13/2023
	** Signature of Reporting Person	Date
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