Dianthus (DNTH) CFO exercises options and sells shares under 10b5-1 plan

Rhea-AI Filing Summary

Insider transactions at Dianthus Therapeutics (DNTH): Chief Financial & Business Officer Ryan Savitz executed and sold shares under a Rule 10b5-1 plan on 09/09/2025. He exercised a stock option to buy 20,000 shares at a $8.44 exercise price and simultaneously sold 20,000 shares at $35 per share. After these transactions, the reporting person beneficially owns 104,766 shares of common stock. The option award underlying the exercise vests over time, with 25% vested on 06/02/2023 and the remainder vesting monthly over the following three years. The filing was signed by an attorney-in-fact on 09/11/2025.

Positive

• Transaction executed under a Rule 10b5-1 plan, indicating the sale was pre-planned and provides an affirmative defense for the insider
• Exercise price of $8.44 vs sale price of $35 shows the executive captured a significant spread on vested options

Negative

• Insider sale of 20,000 shares could be viewed negatively by some investors as insider monetization, though it was pre-planned
• No company-wide context provided in the filing to gauge the relative size or timing impact of the transaction on overall insider ownership

Insights

Corporate Governance Expert

TL;DR: Routine option exercise and sale under a pre-established 10b5-1 plan; no indication of new company-specific material information.

This Form 4 reports a pre-planned exercise and contemporaneous sale by an executive using a Rule 10b5-1 trading plan adopted March 31, 2025. Such plans are commonly used to mitigate insider trading concerns and provide an affirmative defense under Rule 10b5-1. The disclosure includes vesting details for the option award, indicating standard time-based vesting that began June 2, 2023. From a governance perspective, the filing is compliant and transparent about the plan and vesting.

Securities Analyst

TL;DR: Executive monetized vested options at a substantially higher market price than the strike; transaction appears routine and non-disruptive.

The reporting person exercised 20,000 option shares at $8.44 and sold 20,000 shares at $35, realizing the spread between exercise price and sale price. Post-transaction beneficial ownership is 104,766 shares, which remains meaningful but requires company-wide context to assess materiality. The use of a 10b5-1 plan reduces timing concerns; absent other disclosures, this is a standard insider liquidity event rather than a signal of material corporate change.

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Savitz Ryan

(Last) (First) (Middle)

C/O DIANTHUS THERAPEUTICS, INC.

7 TIMES SQUARE, 43RD FLOOR

(Street)

NEW YORK NY 10036

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Dianthus Therapeutics, Inc. /DE/ [ DNTH ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CFO & CBO

3. Date of Earliest Transaction (Month/Day/Year)
09/09/2025

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

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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/09/2025		M(1)		20,000	A	$8.44	20,000	D
Common Stock	09/09/2025		S(1)		20,000	D	$35	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$8.44	09/09/2025		M(1)		20,000		(2)	06/06/2032	Common Stock	20,000	$0	104,766	D

Explanation of Responses:

1. The option exercises and sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 31, 2025.

2. The shares of common stock underlying this stock option award vested as to 25% of the shares on June 2, 2023, with the remaining three quarters vesting in equal monthly installments over the following three years, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

	/s/ Adam Veness, as attorney-in-fact for Ryan Savitz	09/11/2025
	** 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 4 (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.

FAQ

What transactions were reported for DNTH on this Form 4?

The Form 4 reports that Ryan Savitz exercised 20,000 option shares at an $8.44 exercise price and sold 20,000 shares at $35 on 09/09/2025 under a 10b5-1 plan.

How many DNTH shares does the reporting person own after the transactions?

After the reported transactions, the reporting person beneficially owns 104,766 shares of Dianthus Therapeutics common stock.

Was the sale spontaneous or pre-planned for DNTH insider trades?

The sale and option exercise were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 31, 2025.

What are the vesting terms for the option exercised by the DNTH executive?

The underlying option vested 25% on 06/02/2023, with the remaining three quarters vesting in equal monthly installments over the following three years, subject to continued service.

Who signed the Form 4 for the reporting person?

The Form 4 was signed by Adam Veness, as attorney-in-fact for Ryan Savitz on 09/11/2025.