EX-4.5





 Exhibit 4.5 

FIRST SUPPLEMENTAL INDENTURE 

FIRST SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of
November 19, 2019, between HZNP FINANCE LIMITED (the “Guaranteeing Entity”), a subsidiary of Horizon Therapeutics USA, Inc. (formerly known as Horizon Pharma USA, Inc.), a Delaware corporation (the “Issuer”),
and U.S. Bank National Association, as trustee under the Indenture referred to below (the “Trustee”). 
 W I T N E S S E T H

 WHEREAS, the Issuer has heretofore executed and delivered to the Trustee an indenture (the “Indenture”), dated as of
July 16, 2019 providing for the issuance of 5.500% Senior Notes due 2027 (the “Notes”); 
 WHEREAS, the Indenture
provides that under certain circumstances the Guaranteeing Entity shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Entity shall unconditionally guarantee all of the Issuer’s Obligations under
the Notes and the Indenture on the terms and conditions set forth herein (the “Note Guarantee”); and 
 WHEREAS, pursuant
to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture. 
 NOW, THEREFORE, in
consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Entity and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the
Notes as follows: 
 1.    CAPITALIZED TERMS. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture. 
 2.    AGREEMENT
TO GUARANTEE. The Guaranteeing Entity hereby agrees to provide an unconditional Guarantee on the terms and subject to the conditions set forth in the Note Guarantee and in the Indenture including but not limited to
Article 10 thereof. 
 3.    NO RECOURSE AGAINST OTHERS. No
director, officer, employee, incorporator or stockholder of the Issuer or any Guarantor, as such, will have any liability for any obligations of the Issuer or the Guarantors under the Notes, this Indenture, the Note Guarantees or for any claim based
on, in respect of, or by reason of, such obligations or their creation. Each Holder of Notes by accepting a Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes. The waiver may
not be effective to waive liabilities under the federal securities laws. 
 4.    NEW YORK LAW TO GOVERN; WAIVER OF JURY
TRIAL. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK. THE ISSUER AND THE GUARANTORS CONSENTS AND IRREVOCABLY SUBMITS TO THE JURISDICTION OF ANY NEW YORK STATE OR U.S. FEDERAL
COURT LOCATED IN THE BOROUGH OF MANHATTAN, CITY OF NEW YORK, COUNTY OF NEW YORK, STATE OF NEW YORK IN RELATION TO ANY LEGAL ACTION OR PROCEEDING (I) ARISING OUT OF, RELATING TO OR IN CONNECTION WITH THIS INDENTURE, AS SUPPLEMENTED, THE NOTES,
THE GUARANTEES AND ANY RELATED DOCUMENTS AND/OR (II) ARISING UNDER 












 
ANY U.S. FEDERAL OR U.S. STATE SECURITIES LAWS IN RESPECT OF THE NOTES, THE GUARANTEES AND ANY SECURITIES ISSUED PURSUANT TO THE TERMS OF THE INDENTURE, AS SUPPLEMENTED. THE ISSUER AND THE
GUARANTORS WAIVES ANY OBJECTION TO PROCEEDINGS IN ANY SUCH COURTS, WHETHER ON THE GROUND OF VENUE OR ON THE GROUND THAT THE PROCEEDINGS HAVE BEEN BROUGHT IN AN INCONVENIENT FORUM. THE ISSUER AND THE GUARANTORS, TO THE EXTENT ORGANIZED OUTSIDE OF THE
UNITED STATES, SHALL APPOINT HORIZON PHARMA USA, INC. (HORIZON PHARMA USA, INC., 150 S SAUNDERS ROAD, LAKE FOREST, IL 60045), AS ITS AGENT FOR SERVICE OF PROCESS IN ANY SUCH SUIT, ACTION OR PROCEEDING AND AGREES THAT SERVICE OF PROCESS UPON SAID
AUTHORIZED AGENT SHALL BE DEEMED IN EVERY RESPECT EFFECTIVE SERVICE OF PROCESS UPON IT IN ANY SUCH SUIT, ACTION OR PROCEEDING. THE ISSUER AND THE GUARANTORS AGREES TO DELIVER, UPON THE EXECUTION AND DELIVERY OF THIS SUPPLEMENTAL INDENTURE, A WRITTEN
ACCEPTANCE BY SUCH AGENT OF ITS APPOINTMENT AS SUCH AGENT. THE ISSUER AND THE GUARANTORS, TO THE EXTENT ORGANIZED OUTSIDE OF THE UNITED STATES, FURTHER AGREES TO TAKE ANY AND ALL ACTION, INCLUDING THE FILING OF ANY AND ALL SUCH DOCUMENTS AND
INSTRUMENTS, AS MAY BE REASONABLY NECESSARY TO CONTINUE SUCH DESIGNATION AND APPOINTMENT OF CT CORPORATION SYSTEM IN FULL FORCE AND EFFECT FOR SO LONG AS THE INDENTURE, AS SUPPLEMENTED, REMAINS IN FORCE. THE ISSUER, THE TRUSTEE AND EACH OF THE
GUARANTORS HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS SUPPLEMENTAL INDENTURE OR THE TRANSACTIONS CONTEMPLATED HEREBY.

 5.    COUNTERPARTS. The parties may sign any number of copies of this Supplemental Indenture. Each
signed copy (which may be provided via facsimile or other electronic transmission) shall be an original, but all of them together represent the same agreement. 

6.    EFFECT OF HEADINGS. The Section headings herein are for convenience
only and shall not affect the construction hereof. 
 7.    THE TRUSTEE. The Trustee shall
not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Entity and
the Issuer. 
 8.    RATIFICATION OF INDENTURE; SUPPLEMENTAL
INDENTURE PART OF INDENTURE. Except as expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in
full force and effect. This Supplemental Indenture shall form a part of the Indenture for all purposes. 












 IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly
executed and attested, all as of the date first above written. 
  

			
	HZNP FINANCE LIMITED
		
	By:	 	/s/ Kevin Insley
		 	 Name: Kevin Insley
 Title:
Director



  

			
	 U.S. BANK NATIONAL ASSOCIATION,

  as Trustee

		
	By:	 	/s/ Richard Prokosch
		 	 Name: Richard Prokosch

Title:   Vice President



  
 [Signature Page – Horizon
Supplemental Indenture]