X0306 4 2020-02-27 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 2020-02-27 4 S 0 1546 15.787 D 51882 D Common Stock 2020-02-28 4 S 0 889 15.445 D 50993 D 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 transactions reported in this Form 4 were 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. The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 13, 2019. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.120 to $15.710, inclusive. The reporting person undertakes to provide to Lantheus Holdings, Inc. (LNTH), any security holder of LNTH or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (3) to this Form 4. /s/ Michael P. Duffy, attorney-in-fact 2020-03-02