X0306 4 2022-02-28 0 0001521036 Lantheus Holdings, Inc. LNTH 0001754976 Marshall Robert J. Jr. C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD NORTH BILLERICA MA 01862 0 1 0 0 CFO and Treasurer Common Stock 2022-02-28 4 A 0 8776 0.00 A 135783 D Common Stock 2022-03-01 4 S 0 8851 48.037 D 126932 D The transaction reported in this Form 4 reflects additional shares of common stock issued by the Company to the reporting person upon the vesting of relative Total Shareholder Return performance-based restricted stock units ("PSUs") that were previously granted and reported on a Form 4 filed on February 28, 2019. That original Form 4 reflected 100% of the target number of shares underlying the PSUs. The number of shares that actually vested under the PSUs equaled 188% of the target number of shares. Accordingly, the number of shares reported in this Form 4 reflects the difference between the number of shares that actually vested under the PSUs and the target number of shares originally reported. The Company requires certain senior executives to cover tax liabilities resulting from the vesting of their equity awards pursuant to sell-to-cover transactions in compliance with Rule 10b5-1. The transaction reported in this Form 4 was effected in compliance with Rule 10b5-1 to satisfy withholding tax liabilities of the Reporting Person associated with the vesting of restricted stock previously granted and reported on a previously filed Form 4. /s/ Daniel M. Niedzwiecki, attorney-in-fact 2022-03-02