Dianthus director exercises options, sells 599 shares

Dianthus Therapeutics director Paula Soteropoulos exercised stock options and sold the resulting shares.

Accepted by SEC EDGAR 04/01/2026 - 05:26 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Dianthus Therapeutics director Paula Soteropoulos exercised stock options and sold the resulting shares. On March 31, 2026, she exercised options for 599 shares of common stock at $8.44 per share and immediately sold all 599 shares at $80.11 per share in an open-market transaction.

The transaction was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on December 23, 2025. Following the sale, the filing shows 0 common shares held directly from this transaction.

Insider Trade Summary 10b5-1

Exercise and Sale: 599 shares ($43K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Soteropoulos Paula

Role Director

Sold 599 shs ($48K)

Approx. gross sale proceeds $48K

Approx. exercise cost $5K

Approx. pre-tax spread $43K

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy)	599	$0.00	$0.00
Exercise	Common Stock	599	$8.44	$5K
Sale	Common Stock	599	$80.11	$48K

Holdings After Transaction: Stock Option (Right to Buy) — 599 contracts (Direct); Common Stock — 0 shares (Direct)

Footnotes (2)

1. F1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 23, 2025.
2. F2. The shares of common stock underlying this stock option award vested as to 25% of the shares on April 6, 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.

Key Figures

Shares exercised: 599 shares Exercise price: $8.44 per share Shares sold: 599 shares +4 more

7 metrics

Shares exercised 599 shares Options exercised into common stock on March 31, 2026

Exercise price $8.44 per share Stock Option (Right to Buy) into common stock

Shares sold 599 shares Open-market sale on March 31, 2026

Sale price $80.11 per share Common stock sale following option exercise

Rule 10b5-1 plan adoption date December 23, 2025 Pre-arranged trading plan governing the reported transaction

Option expiration date June 6, 2032 Expiration for the exercised stock option

Net shares change -599 shares Net of exercise and sale in transaction summary

Key Terms

Stock Option (Right to Buy), Rule 10b5-1 trading plan, open-market sale, derivative exercise/conversion, +1 more

5 terms

Stock Option (Right to Buy) financial

"security_title: "Stock Option (Right to Buy)" for 599 underlying shares"

Rule 10b5-1 trading plan regulatory

"reported transaction was effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

open-market sale financial

"transaction_action: "open-market sale" at $80.11 per share"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

derivative exercise/conversion financial

"transaction_action: "derivative exercise/conversion" for the stock option"

vesting financial

"shares of common stock underlying this stock option award vested as to 25% of the shares"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did DNTH director Paula Soteropoulos report?

Paula Soteropoulos reported exercising stock options for 599 shares of Dianthus Therapeutics common stock and selling all 599 shares on March 31, 2026. The sale followed the option exercise and reflects a single exercise-and-sell sequence disclosed in this Form 4.

At what prices did the DNTH director exercise and sell her shares?

She exercised stock options at $8.44 per share and sold the resulting 599 common shares at $80.11 per share. These transactions occurred on March 31, 2026, with the option exercise immediately followed by an open-market sale of the same number of shares.

How many Dianthus Therapeutics (DNTH) shares were sold in this Form 4?

The Form 4 shows an open-market sale of 599 shares of Dianthus Therapeutics common stock. Those 599 shares came directly from the same-day exercise of stock options for 599 underlying shares, so the entire exercised amount was sold in this reported transaction.

Was the DNTH insider transaction made under a Rule 10b5-1 trading plan?

Yes. A footnote states the reported transaction was executed under a Rule 10b5-1 trading plan adopted by the reporting person on December 23, 2025. Such plans pre-schedule trades, indicating the timing was established in advance rather than decided on the trade date.

What type of derivative security did the DNTH director exercise?

She exercised a “Stock Option (Right to Buy)” covering 599 shares of Dianthus Therapeutics common stock at an exercise price of $8.44 per share. The option carried an expiration date of June 6, 2032, and the exercise converted it into common stock before sale.

What are the post-transaction holdings reported in this DNTH Form 4?

For the 599 common shares involved in this sequence, the filing reports total shares following the sale as 0. This reflects that all shares acquired through the option exercise on March 31, 2026, were sold in the same reportable event.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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^*

Soteropoulos Paula

(Last) (First) (Middle)

C/O DIANTHUS THERAPEUTICS, INC.

7 TIMES SQUARE, 43RD FLOOR

(Street)

NEW YORK NEW YORK 10036

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/31/2026

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

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

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

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	03/31/2026		M(1)		599	A	$8.44	599	D
Common Stock	03/31/2026		S(1)		599	D	$80.11	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	03/31/2026		M(1)			599	(2)	06/06/2032	Common Stock	599	$0	599	D

Explanation of Responses:

1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 23, 2025.

2. The shares of common stock underlying this stock option award vested as to 25% of the shares on April 6, 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 Paula Soteropoulos	04/01/2026
	** 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 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.
* Form 4: SEC 1474 (03-26)