SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES 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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1. Name and Address of Reporting Person* Avista Capital Partners GP, LLC (Last) (First) (Middle) C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD (Street) NORTH BILLERICA MA 01862 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 06/24/2015	3. Issuer Name and Ticker or Trading Symbol Lantheus Holdings, Inc. [ LNTH ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	17,793,599	I	Affilliated Funds(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Avista Capital Partners GP, LLC (Last) (First) (Middle) C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD (Street) NORTH BILLERICA MA 01862 (City) (State) (Zip)

1. Name and Address of Reporting Person* Avista Capital Partners, L.P. (Last) (First) (Middle) C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD (Street) NORTH BILLERICA MA 01862 (City) (State) (Zip)

1. Name and Address of Reporting Person* Avista Capital Partners (Offshore), L.P. (Last) (First) (Middle) C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD (Street) NORTH BILLERICA MA 01862 (City) (State) (Zip)

1. Name and Address of Reporting Person* ACP-Lantern Co-Invest, LLC (Last) (First) (Middle) C/O LANTHEUS HOLDINGS, INC. 331 TREBLE COVE ROAD (Street) NORTH BILLERICA MA 01862 (City) (State) (Zip)

Explanation of Responses:

1. Avista Capital Partners GP, LLC ultimately exercises voting and dispositive power over the securities held by Avista Capital Partners, L.P., Avista Capital Partners (Offshore), L.P. and ACP-Lantern Co-Invest, LLC. The reporting person disclaims beneficial ownership of these securities except to the extent of its pecuniary interest therein, and the inclusion of shares in this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities so disclaimed for purposes of Section 16 or for any other purpose.

Remarks:

	/s/ David Burgstahler, President and Partner	06/24/2015
	** 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 5 (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).
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