On March 27, 2023, Milestone Pharmaceuticals Inc. entered into a Purchase and Sale Agreement with RTW Investments, LP and certain of its affiliates (collectively, “RTW”). Pursuant to the Royalty Purchase Agreement, RTW agreed to purchase, following U.S. Food and Drug Administration (“FDA”) approval of etripamil (subject to certain conditions), in exchange for a purchase price of $75.0 million, the right to receive a tiered quarterly royalty payments (the “royalty interest”) on the annual net product sales of etripamil in the United States in an amount equal to: (i) 7% (the “Initial Tier Royalty”) of annual net sales up to $500 million, (ii) 4% of annual net sales greater than $500 million and less than or equal to $800 million, and (iii) 1% of annual net sales greater than $800 million. If certain revenue thresholds for aggregate annual net sales in the United States are not met, the Initial Tier Royalty will increase to 9.5% beginning on January 1 of the following calendar year until a subsequent sales threshold is attained, at which time the Initial Tier Royalty would revert back to 7%.

The Royalty Purchase Agreement contains various representations and warranties, covenants, indemnification obligations and other provisions customary for transactions of this nature, including the grant of a back-up security interests in the purchased royalties and certain assets related to etripamil and restrictions on the incurrence of additional indebtedness.