Korsana Biosciences, Inc.

Recent Developments

The Merger and Pre-Closing Financing

On April 1, 2026, Korsana and Cyclerion entered into an Agreement and Plan of Merger (as subsequently amended on April 17, 2026), subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement. On September 8, 2026, Korsana completed the Merger with Cyclerion in accordance with the terms of the Merger Agreement. The Combined Company will be led by Korsana’s management team and remains focused on discovering and developing novel therapies designed to reduce the burden of neurodegenerative diseases, starting with Alzheimer’s disease.

Immediately prior to the completion of the Merger, and in order to provide Korsana with additional capital for its development programs, Pre-Merger Korsana issued and sold, and certain new and current investors purchased, 140,516,578 shares of common stock of Pre-Merger Korsana and 20,171,961 Pre-Merger Korsanapre-funded warrants, exercisable for 20,171,961 shares of Pre-Merger Korsana common stock, at a purchase price of $2.3648 per share or a purchase price of $2.3647 per warrant, for the aggregate amount of $380.0 million (the“Pre-Closing Financing”, and together with the Merger, the “Transactions”).

In accordance with an exchange ratio determined in accordance with the terms of the Merger Agreement (the “Exchange Ratio”), at the effective time of the First Merger (the “First Effective Time”), (i) each then-outstanding share of Pre-Merger Korsana common stock (including shares of Pre-Merger Korsana common stock issued in connection with the Korsana Pre-Closing Financing) was converted into the right to receive a number of shares of Cyclerion common stock equal to the Exchange Ratio, (ii) each then-outstanding share of Pre-Merger Korsana Preferred Stock was converted into the right to receive a number of shares of Korsana Series Anon-voting convertible preferred stock, par value $0.0001 per share (the “Series A Preferred Stock”), equal to the Exchange Ratio divided by 1,000, (iii) each then-outstanding option to purchase Pre-Merger Korsana common stock was assumed by Cyclerion and was converted into an option to purchase shares of Cyclerion common stock, and (iv) each then-outstanding Pre-Merger Korsana restricted stock unit was assumed by Cyclerion; (v) each then-outstandingpre-funded warrant to purchase shares of Pre-Merger Korsana common stock was converted into apre-funded warrant to purchase shares of Cyclerion common stock.

The Exchange Ratio is calculated as 0.2074 shares of Cyclerion common stock for each share of Pre-Merger Korsana common stock (and 0.0002074 shares of Series A Preferred Stock for each share of Convertible Preferred Stock) on the Closing Date, which gives effect to aone-for-seven reverse stock split of Cyclerion common shares immediately prior to the Merger. After the closing of the Merger, Pre-Merger Korsana stockholders immediately before the First Effective Time, including those that purchased shares andpre-funded warrants in the Korsana Pre-Closing Financing, own approximately 98.9% of the outstanding common stock of the Combined Company and the stockholders of Cyclerion immediately before the First Effective Time own 1.1% of the outstanding common stock of the Combined Company, which give effect to (a) Cyclerion’s Net Cash (as defined in the Merger Agreement) as of the closing being approximately $(2.3) million, (b) the Korsana Pre-Closing Financing for an aggregate purchase price of approximately $380.0 million, (c) a valuation for Cyclerion equal to its Net Cash equal to $7.7 million based on net cash of $(2.3) million at closing, and (d) a valuation for Korsana equal to $268.4 million plus $380.0 million of assumed proceeds in the Korsana Pre-Closing Financing, in each case as further described in the Merger Agreement.

At the Closing of the Merger based on the Exchange Ratio, the Korsana common stock andpre-funded warrants subscribed for were converted into the right to receive 29,143,139 shares of common stock and 4,183,665 pre-funded warrants. Shares of Korsana common stock andpre-funded warrants to purchase shares of Korsana common stock issued pursuant to the Subscription Agreement were converted into shares of Cyclerion common stock andpre-funded warrants to purchase shares of Cyclerion common stock at Closing per the Merger Agreement.