Form 4 Filing for Jonathan Violin

This filing details a Form 4 submission by Jonathan Violin, an officer and director of Korsana Biosciences, Inc. (formerly Cyclerion Therapeutics, Inc.). The filing follows a merger effective September 8, 2026, where Cyclerion Therapeutics, Inc. acquired Korsana Biosciences, Inc. (Pre-Merger Korsana). Jonathan Violin received shares and stock options in the new entity, Korsana Biosciences, Inc., in exchange for his holdings in Pre-Merger Korsana. Some of the shares received are subject to forfeiture and vest over time through June 1, 2029. Stock options also have specific vesting schedules tied to continued service. The filing also includes a Power of Attorney document, granting Mark Vignola and others the authority to execute and file necessary SEC forms on behalf of Mr. Violin.