X0306 4 2023-03-02 0 0001521036 Lantheus Holdings, Inc. LNTH 0001861113 Niedzwiecki Daniel C/O LANTHEUS HOLDINGS, INC. 201 BURLINGTON ROAD, SOUTH BLDG BEDFORD MA 01730 0 1 0 0 See Remarks Common Stock 2022-03-02 4 A 0 12346 0.00 A 77489 D Common Stock 2023-03-03 4 A 0 7515 0.00 A 85004 D Stock Option (right to buy) 73.35 2023-03-02 4 A 0 7196 0.00 A 2033-03-02 Common Stock 7196 7196 D Consists of 4,115 restricted stock units that vest in equal installments over a three-year period and 8,231 Total Shareholder Return performance-based restricted stock units ("PSUs") that cliff vest following a three-year performance period. The amount of PSUs included in this Report reflects the target award, however the ultimate award size can range from 0% to 200% of the target based on the actual performance achieved at the end of the performance period. 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 PSUs that were previously granted and included in the Form 3 filed upon the reporting person becoming a Section 16 officer. The number of shares reported in the Form 3 reflected 100% of the target number of shares underlying the PSUs. The number of shares that actually vested under the PSUs equaled 200% 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 included in the Form 3. The option vests in three equal annual installments beginning on March 2, 2024. Senior Vice President, General Counsel and Corporate Secretary /s/ Eric M. Green, attorney-in-fact 2023-03-06