Form 4 Filing for Spero Therapeutics, Inc. - Kathleen Tregoning Stock Transactions

On June 23, 2026, Kathleen Tregoning, a director at Spero Therapeutics, Inc., acquired 10,000 shares of common stock and was granted 20,000 stock options. The common stock acquisition, valued at $0.00 per share, is associated with restricted stock units (RSUs) that vest on June 23, 2027. The stock options, also granted at $0.00 per share, have an exercise price of $2.15 and will vest on June 23, 2027. Following these transactions, Tregoning holds 85,000 shares of common stock and 20,000 stock options. These transactions were reported on a Form 4 filing dated June 25, 2026.