SEC Form 4 
FORM 4	UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940 	  
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	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).			
1. Name and Address of Reporting Person*
DUFFY MICHAEL P	

(Last)	(First)	(Middle)	
C/O LANTHEUS HOLDINGS, INC.	
331 TREBLE COVE ROAD	

(Street) 
NORTH BILLERICA	MA	01862	

(City)	(State)	(Zip)	
	2. Issuer Name and Ticker or Trading Symbol 
Lantheus Holdings, Inc. [ LNTH ] 	5. Relationship of Reporting Person(s) to Issuer 
(Check all applicable) 
	Director		10% Owner	
X	Officer (give title below)		Other (specify below)	
See Remarks	
		
	3. Date of Earliest Transaction (Month/Day/Year)
04/03/2018 		
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) 
X	Form filed by One Reporting Person	
	Form filed by More than One Reporting Person	
	
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned	
1. Title of Security (Instr. 3) 	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8) 	4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 	5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 	7. Nature of Indirect Beneficial Ownership (Instr. 4) 	
			Code	V	Amount	(A) or (D)	Price				
Common Stock	04/03/2018		M(1) 		27,313	A	$5.62 	191,472	D		
Common Stock	04/03/2018		S(1) 		27,313	D	$15.3003(2) 	164,159	D		
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities) 	
1. Title of Derivative Security (Instr. 3) 	2. Conversion or Exercise Price of Derivative Security 	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8) 	5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 	6. Date Exercisable and Expiration Date (Month/Day/Year)	7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 	8. Price of Derivative Security (Instr. 5) 	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 	11. Nature of Indirect Beneficial Ownership (Instr. 4) 	
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares					
Stock Option (right to buy)	$5.62 	04/03/2018		M(1) 			27,313	(3) 	04/04/2018	Common Stock	27,313	$0.00 	0	D		
Explanation of Responses:	
1. The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 12, 2017.	
2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.05 to $15.65, 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 ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.	
3. These options were originally granted on April 4, 2008, and originally provided for vesting based on the level of LNTH's satisfaction of certain performance criteria for each of fiscal years 2009, 2010, 2011 and 2012. As previously reported on a Form 4 filed with the SEC on June 25, 2015, these options were amended in connection with LNTH's initial public offering on June 25, 2015 to provide for additional vesting on the third anniversary of the amendment date (or the day before any earlier expiration) of any options that remain unvested at that time. As a result, these options became exercisable on April 3, 2018, one day prior to their expiration on April 4, 2018.	
Remarks:	
SVP, General Counsel and Secretary	
	/s/ Daniel Niedzwiecki, attorney-in-fact	04/05/2018	
	** Signature of Reporting Person	Date	
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.	
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).	
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).	
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.	
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.