A Form 4 filed on August 19, 2026 with the U.S. Securities and Exchange Commission discloses that Simon Read, a director of Dianthus Therapeutics, Inc. (NASDAQ:DNTH), exercised stock options and sold common stock on August 19, 2026 pursuant to a Rule 10b5-1 trading plan.

Key Highlights

  • Option exercise: Simon Read exercised stock options covering 2,778 shares of common stock at an exercise price of $18.36 per share on August 19, 2026.
  • Shares sold: 2,778 shares of common stock were disposed of at a weighted average price of $117.55 per share, with individual sales ranging from $117.01 to $117.66.
  • Resulting ownership: Following the transactions, Read directly holds 0 shares of common stock and 19,445 stock options (right to buy).
  • 10b5-1 plan: Both transactions were effected pursuant to a Rule 10b5-1 trading plan adopted on May 8, 2026.
  • Option vesting schedule: The underlying stock option award vests as to one-third of the shares on each of the first, second, and third anniversaries of the date of grant, subject to continued service.

Simon Read's Option Exercise and Share Sale at Dianthus Therapeutics

According to the filing, Simon Read, identified as a director of Dianthus Therapeutics, Inc. /DE/, reported two transactions on August 19, 2026. First, Read exercised stock options (transaction code M) to acquire 2,778 shares of common stock at a conversion or exercise price of $18.36 per share. Immediately following the exercise, those 2,778 shares were sold (transaction code S) at a weighted average price of $117.55 per share.

The filing notes that the shares were sold in multiple transactions at prices ranging from $117.01 to $117.66, inclusive. The filing states that Read "undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range." Both the exercise and the sale were carried out under a Rule 10b5-1 trading plan that Read adopted on May 8, 2026.

After these transactions, the filing reports that Read's direct beneficial ownership of common stock stands at 0 shares. Read retains 19,445 stock options (right to buy) with an expiration date of May 22, 2035. The option vesting terms, as disclosed, provide that one-third of the shares vest on each of the first, second, and third anniversaries of the grant date, subject to continued service. The Form 4 was signed by Adam Veness as attorney-in-fact for Simon Read.

What Was Disclosed

The filing reports the exercise of 2,778 stock options at $18.36 and the same-day sale of 2,778 common shares at a weighted average of $117.55, both under a pre-established 10b5-1 plan, leaving Read with 0 shares and 19,445 remaining options.