RANDHAWA SIMRAT (EVP, Head of R&D) sold 86.9% of their position (26.53K shares) of DIANTHUS THERAPEUTICS, INC. /DE/ on the open market

Open‑market sale worth $2.40M — a major position exit. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 3 sales

RANDHAWA SIMRAT

Filed: 6/2/2026ACC: 0001992260-26-000006

InsiderRANDHAWA SIMRATCIK 1992260

→

IssuerDIANTHUS THERAPEUTICS, INC. /DE/CIK 1690585

Officer· EVP, Head of R&D

Since Mar 2026

-26.53K

Net shares

Net seller

$2.40M

Total sold

Open market trades

0B · 3S

Total transactions

26.53K acquired · 53.06K disposed

Non-Derivative Transactions7

Common Stock

Direct

M · Option Exercise

+4K

Price / share

$8.44

Trade value

$33.74K

% of position

100.0%

6/1/2026

4K→8K

Common Stock

Direct

M · Option Exercise

+6.91K

Price / share

$17.88

Trade value

$123.52K

% of position

86.4%

6/1/2026

8K→14.91K

Common Stock

Direct

M · Option Exercise

+6.25K

Price / share

$21.77

Trade value

$136.04K

% of position

41.9%

6/1/2026

14.91K→21.16K

Common Stock

Direct

M · Option Exercise

+9.38K

Price / share

$22.07

Trade value

$206.91K

% of position

44.3%

6/1/2026

21.16K→30.53K

Common Stock

Direct

S · Sale

−5.43K

Price / share

$89.72

Trade value

$487K

% of position

17.8%

6/1/2026

30.53K→25.10K

Common Stock

Direct

S · Sale

−16.94K

Price / share

$90.72

Trade value

$1.54M

% of position

67.5%

6/1/2026

25.10K→8.16K

Common Stock

Direct

S · Sale

−4.16K

Price / share

$91.37

Trade value

$380.01K

% of position

51.0%

6/1/2026

8.16K→4K

Total

Net shares

+0.00

Net value

-$1.90M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	6/1/2026	M · Option Exercise	+4K	$8.44	$33.74K	100.0%	4K	8K
Common Stock Direct	6/1/2026	M · Option Exercise	+6.91K	$17.88	$123.52K	86.4%	8K	14.91K
Common Stock Direct	6/1/2026	M · Option Exercise	+6.25K	$21.77	$136.04K	41.9%	14.91K	21.16K
Common Stock Direct	6/1/2026	M · Option Exercise	+9.38K	$22.07	$206.91K	44.3%	21.16K	30.53K
Common Stock Direct	6/1/2026	S · Sale	−5.43K	$89.72	$487K	17.8%	30.53K	25.10K
Common Stock Direct	6/1/2026	S · Sale	−16.94K	$90.72	$1.54M	67.5%	25.10K	8.16K
Common Stock Direct	6/1/2026	S · Sale	−4.16K	$91.37	$380.01K	51.0%	8.16K	4K
Total			+0.00		-$1.90M

Derivative Transactions4

Stock Option (Right to Buy)

Direct

M · Option Exercise

Converts to

Common Stock

4K shares

−4K

Strike price

8.44

Held after

0.00

Exercisable

—

6/1/2026

Stock Option (Right to Buy)

Direct

M · Option Exercise

Converts to

Common Stock

6.91K shares

−6.91K

Strike price

17.88

Held after

64.28K

Exercisable

—

6/1/2026

Stock Option (Right to Buy)

Direct

M · Option Exercise

Converts to

Common Stock

6.25K shares

−6.25K

Strike price

21.77

Held after

47.92K

Exercisable

—

6/1/2026

Stock Option (Right to Buy)

Direct

M · Option Exercise

Converts to

Common Stock

9.38K shares

−9.38K

Strike price

22.07

Held after

96.88K

Exercisable

—

6/1/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Stock Option (Right to Buy) Direct	Common Stock4K shares	6/1/2026	M · Option Exercise	−4K	8.44	—	0.00
Stock Option (Right to Buy) Direct	Common Stock6.91K shares	6/1/2026	M · Option Exercise	−6.91K	17.88	—	64.28K
Stock Option (Right to Buy) Direct	Common Stock6.25K shares	6/1/2026	M · Option Exercise	−6.25K	21.77	—	47.92K
Stock Option (Right to Buy) Direct	Common Stock9.38K shares	6/1/2026	M · Option Exercise	−9.38K	22.07	—	96.88K