X4 Pharmaceuticals, Inc

19. Gain on Sale of Nonfinancial Asset

In May 2024, the Company entered into contractual arrangement with a third party that transferred the rights to a Priority Review Voucher (“PRV”) awarded to the Company as a result of the FDA’s approval of XOLREMDI. During the year ended December 31, 2024, the PRV was accounted for as an intangible asset with no accounting cost basis. The third party purchased the PRV for $105.0 million. There were no fees associated with the sale and the Company has no continuing obligations with respect to the PRV. The Company concluded that the third party is “non-customer” as the underlying PRV is not an output of the Company’s ordinary commercial activities. Accordingly, the Company accounted for this transaction under ASC Topic 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets (“ASC 610-20”). As a result of the transfer of control of the PRV to the third party, the Company derecognized the associated intangible asset and recorded a gain through “gain on sale of non-financial assets.” There was no such arrangement for year ended December 31, 2025.