Lantheus Holdings, Inc. 5,200,000 Shares Common Stock ($0.01 par value) Underwriting Agreement

Exhibit 1.1

Lantheus Holdings, Inc.

5,200,000 Shares

Common Stock

($0.01 par value)

Underwriting Agreement

New York, New York

September 8, 2016

Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, New York 10010

Jefferies LLC

520 Madison Avenue

New York, New York 10022

Ladies and Gentlemen:

Lantheus Holdings, Inc., a corporation organized under the laws of the State of Delaware (the “Company”), proposes to sell to the several underwriters named in Schedule I hereto (the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof, and to the extent there is only a single underwriter, the term “Underwriters” shall be deemed to refer to the single Underwriter, mutatis mutandis), 5,200,000 shares of common stock, $0.01 par value (“Common Stock”) of the Company (said shares to be issued and sold by the Company being hereinafter called the “Securities”). Any reference herein to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 which were filed under the Exchange Act on or before the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Prospectus, as the case may be; and any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the filing of any document under the Exchange Act after the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Prospectus, as the case may be, deemed to be incorporated therein by reference. Certain terms used herein are defined in Section 20 hereof.

1. Representations and Warranties. The Company represents and warrants to, and agrees with, each Underwriter as set forth below in this Section 1.

(a) The Company meets the requirements for use of Form S-3 under the Act and has prepared and filed with the Commission a registration statement (file

number 333-212940) on Form S-3, including a related Base Prospectus, for registration under the Act of the offering and sale of the Securities. Such Registration Statement, including any amendments thereto filed prior to the Execution Time, has become effective. The Company may have filed with the Commission, as part of an amendment to the Registration Statement or pursuant to Rule 424(b), one or more preliminary prospectus supplements relating to the Securities, each of which has previously been furnished to you. The Company will file with the Commission a final prospectus supplement relating to the Securities in accordance with Rule 424(b). As filed, such final prospectus supplement shall contain all information required by the Act and the rules thereunder and, except to the extent the Underwriters shall agree in writing to a modification, shall be in all substantive respects in the form furnished to you prior to the Execution Time or, to the extent not completed at the Execution Time, except as determined to be otherwise required by law, shall contain only such specific additional information and other changes (beyond that contained in the Base Prospectus and any Preliminary Prospectus) as the Company has advised you, prior to the Execution Time, will be included or made therein. The Registration Statement, at the Execution Time, meets the requirements set forth in Rule 415(a)(1)(x). The initial Effective Date of the Registration Statement was not earlier than the date three years before the Execution Time.

(b) On each Effective Date, the Registration Statement did, and on the date when the Prospectus is first filed in accordance with Rule 424(b) and on the Closing Date (as defined herein), the Prospectus (and any supplement thereto) will, comply in all material respects with the applicable requirements of the Act and the Exchange Act and the respective rules thereunder; on each Effective Date, at the Execution Time and on the Closing Date, the Registration Statement did not and will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading; and on the date of any filing pursuant to Rule 424(b) and on the Closing Date, the Prospectus (together with any supplement thereto) will not include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the Company makes no representations or warranties as to the information contained in or omitted from the Registration Statement, or the Prospectus (or any supplement thereto) in reliance upon and in conformity with information furnished in writing to the Company by the Underwriters specifically for inclusion in the Registration Statement or the Prospectus (or any supplement thereto), it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8 hereof.

(c) (i) The Disclosure Package, (ii) each electronic road show, when taken together as a whole with the Disclosure Package, and (iii) any individual Written Testing-the-Waters Communication, when taken together as a whole with the Disclosure Package, does not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based upon and

in conformity with written information furnished to the Company by the Underwriters specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8 hereof.

(d) (i) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Securities and (ii) as of the Execution Time (with such date being used as the determination date for purposes of this clause (ii)), the Company was not and is not an Ineligible Issuer (as defined in Rule 405), without taking account of any determination by the Commission pursuant to Rule 405 that it is not necessary that the Company be considered an Ineligible Issuer.

(e) From the time of initial filing of the Registration Statement with the Commission (or, if earlier, the first date on which the Company engaged directly or through any Person authorized to act on its behalf in any Testing-the-Waters Communication) through the Execution Time, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the Securities Act (an “Emerging Growth Company”). “Testing-the-Waters Communication” means any oral or written communication with potential investors undertaken in reliance on Section 5(d) of the Securities Act.

(f) The Company (i) has not alone engaged in any Testing-the-Waters Communication other than Testing-the-Waters Communications with the consent of the Underwriters with entities that are qualified institutional buyers within the meaning of Rule 144A under the Securities Act or institutions that are accredited investors within the meaning of Rule 501 under the Securities Act and (ii) has not authorized anyone other than the Underwriters to engage in Testing-the-Waters Communications. The Company reconfirms that the Underwriters have been authorized to act on its behalf in undertaking Testing-the-Waters Communications. The Company has not distributed any Written Testing-the-Waters Communications other than those listed on Schedule III hereto. “Written Testing-the-Waters Communication” means any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 under the Securities Act.

(g) Each Issuer Free Writing Prospectus does not include any information that conflicts with the information contained in the Registration Statement on file with the SEC at the time of issuance of such Issuer Free Writing Prospectus, including any document incorporated therein by reference and any prospectus supplement deemed to be part thereof that has not been superseded or modified. The foregoing sentence does not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by any Underwriter specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8 hereof.

(h) The interactive data in the eXtensible Business Reporting Language (“XBRL”) incorporated by reference in the Registration Statement fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(i) The Company and each of its subsidiaries (i) has been duly organized or formed, as the case may be, is validly existing and is in good standing under the laws of its jurisdiction of organization, (ii) has all requisite power and authority to own its properties and conduct its business as described in the Disclosure Package and the Prospectus and (iii) is duly qualified or licensed to do business and is in good standing as a foreign corporation, limited liability company, partnership or other entity as the case may be, authorized to do business in each jurisdiction in which the nature of such businesses or the ownership or leasing of such properties requires such qualification, except where the failure to be so qualified would not, individually or in the aggregate, reasonably be expected to have a material adverse effect on (A) the properties, business, financial condition, prospects or results of operations of the Company and its subsidiaries, taken as a whole, (B) the ability of the Company to perform its obligations in all material respects under this Agreement, or (C) the consummation of any of the transactions contemplated hereby (each, a “Material Adverse Effect”).

(j) All of the issued and outstanding shares of capital stock of the Company and each of its subsidiaries have been duly authorized and validly issued, are fully paid and nonassessable and were not issued in violation of any preemptive or similar rights. The table under the caption “Capitalization” in the Disclosure Package and the Prospectus (including the footnotes thereto) sets forth, as of its date, the actual capitalization of the Company and its subsidiaries on a consolidated basis and the pro forma capitalization of the Company and its subsidiaries on a consolidated basis, after giving effect to the offer and sale of the Securities and the application of the net proceeds therefrom as described in the Disclosure Package, in all material respects. Except as described in the Disclosure Package, all of the outstanding shares of capital stock or other equity interests of each of its subsidiaries are owned, directly or indirectly, by the Company, free and clear of all liens, security interests, mortgages, pledges, charges, equities, claims or restrictions on transferability or encumbrances of any kind (collectively, “Liens”), other than those imposed by the Securities Act and the securities or “Blue Sky” laws of certain U.S. state or non-U.S. jurisdictions. Except as disclosed in the Disclosure Package and the Prospectus, there are no outstanding (A) options, warrants or other rights to purchase from the Company or any of its subsidiaries, (B) agreements, contracts, arrangements or other obligations of the Company or any of its subsidiaries to issue or (C) other rights to convert any obligation into or exchange any securities for, in the case of each of clauses (A) through (C), shares of capital stock of or other ownership or equity interests in the Company or any of its subsidiaries.

(k) There is no franchise, contract or other document of a character required to be described in the Registration Statement or Prospectus, or to be filed as an exhibit thereto, which is not described or filed as required (and the Preliminary Prospectus contains in all material respects the same description of the foregoing matters contained in the Prospectus); and the statements in the Preliminary Prospectus and the Prospectus

under the headings “Description of Capital Stock” and “Description of Material Indebtedness” insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair summaries of such legal matters, agreements, documents or proceedings.

(l) This Agreement has been duly authorized, executed and delivered by the Company.

(m) The Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Disclosure Package and the Prospectus, will not be an “investment company” as defined in the Investment Company Act of 1940, as amended.

(n) No consent, approval, authorization, filing with or order of any court or governmental agency or body is required in connection with the transactions contemplated herein, except such as have been obtained under the Act and such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters in the manner contemplated herein and in the Disclosure Package and the Prospectus.

(o) No holders of securities of the Company have rights to the registration of such securities under the Registration Statement.

(p) The consolidated historical financial statements and schedules of the Company and its consolidated subsidiaries included or incorporated by reference in the Preliminary Prospectus, the Prospectus and the Registration Statement present fairly in all material respects the financial condition, results of operations and cash flows of the Company as of the dates and for the periods indicated, comply in all material respects as to form with the applicable accounting requirements of the Act, the rules of Nasdaq Global Market and the rules of FINRA and have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved (except as otherwise noted therein). The selected financial data set forth under the caption “Selected Consolidated Financial Data” in the Preliminary Prospectus, the Prospectus and Registration Statement fairly present in all material respects, on the basis stated in the Preliminary Prospectus, the Prospectus and the Registration Statement, the information included therein.

(q) There is no action, claim, suit, demand, hearing, notice of violation or deficiency, or proceeding pending or, to the knowledge of the Company or any of its subsidiaries, threatened by Governmental Authorities or threatened by others (collectively, “Proceedings”) that would restrain, enjoin, prevent or interfere with the performance of this Agreement or the consummation of any of the transactions contemplated hereby or would, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(r) Each of the Company and each of its subsidiaries owns or leases all such properties as are necessary to the conduct of its operations as presently conducted.

(s) Neither the Company nor any of its subsidiaries are (i) in violation of its certificate of incorporation, by-laws or other organizational documents (the “Charter Documents”); (ii) in violation of any U.S. or non-U.S. federal, state or local statute, law (including, without limitation, common law) or ordinance, or any judgment, decree, rule, regulation, order or injunction (collectively, “Applicable Law”) of any U.S. or non-U.S. federal, state, local or other governmental or regulatory authority, governmental or regulatory agency or body, court, arbitrator or self-regulatory organization (each, a “Governmental Authority”), applicable to any of them or any of their respective properties; or (iii) in breach of or default under any bond, debenture, note, loan or other evidence of indebtedness, indenture, mortgage, deed of trust, lease or any other agreement or instrument to which any of them is a party or by which any of them or their respective property is bound (collectively, the “Applicable Agreements”), except, in the case of clauses (ii) and (iii) for such violations, breaches or defaults that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(t) Neither the issue and sale of the Securities nor the consummation of any other of the transactions herein contemplated nor the fulfillment of the terms hereof will conflict with, violate, constitute a breach of or a default (with the passage of time or otherwise) or result in the imposition of a lien on any assets of the Company or any of its subsidiaries, pursuant to (i) the Charter Documents, (ii) any Applicable Agreement, or (iii) any Applicable Law, except with respect to clauses (ii) and (iii), for any conflict, violation, breach or default that would not individually or in the aggregate reasonably be expected to result in a Material Adverse Effect.

(u) Deloitte & Touche LLP, who have certified certain financial statements of the Company and its consolidated subsidiaries and delivered their report with respect to the audited consolidated financial statements and schedules included or incorporated by reference in the Disclosure Package and the Prospectus, are independent public accountants with respect to the Company within the meaning of the Act and the applicable published rules and regulations thereunder.

(v) All Tax (as hereinafter defined) returns required to be filed by the Company and each of its subsidiaries have been filed, subject to permitted extensions (except where the failure to so file would not reasonably be expected to result in a Material Adverse Effect). All material Taxes that are due and payable from the Company and its subsidiaries have been paid other than those (i) currently payable without penalty or interest, (ii) being contested in good faith and by appropriate proceedings, (iii) for which adequate accruals have been established in accordance with generally accepted accounting principles of the United States, applied on a consistent basis throughout the periods involved (“GAAP”) or (iv) as would not reasonably be expected to result in a Material Adverse Effect. For purposes of this Agreement, the term “Tax” and “Taxes” shall mean all U.S. and non-U.S. federal, state and local taxes, and other assessments of a similar nature (whether imposed directly or through withholding), including any interest, additions to tax or penalties applicable thereto.

(w) Except as otherwise disclosed in the Disclosure Package and the Prospectus, (i) neither the Company nor any of its subsidiaries is party to or bound by any collective bargaining agreement with any labor organization; (ii) to the knowledge of the Company, no union organizing or decertification efforts are underway or threatened against the Company or its subsidiaries; (iii) no labor strike, work stoppage, slowdown or other material labor dispute is pending against the Company or its subsidiaries, or, to the Company’s knowledge, threatened against the Company or its subsidiaries; (iv) there is no worker’s compensation liability, experience or matter that could be reasonably expected to have a Material Adverse Effect; (v) to the knowledge of the Company, there is no threatened or pending liability against the Company or its subsidiaries pursuant to the Worker Adjustment Retraining and Notification Act of 1988, as amended (“WARN”), or any similar state or local law that could reasonably be expected to have a Material Adverse Effect; and (vi) there is no employment-related charge, complaint, grievance, investigation, unfair labor practice claim or inquiry of any kind, pending against the Company or its subsidiaries that could, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(x) Each of the Company and its subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which they are engaged. All policies of insurance insuring the Company or any of its subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect.

(y) No subsidiary of the Company is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s property or assets to the Company or any other subsidiary of the Company, except as described in or contemplated by the Disclosure Package and the Prospectus (exclusive of any supplement thereto).

(z) Except as otherwise disclosed in the Disclosure Package and the Prospectus, each of the Company and its subsidiaries possess all licenses, permits, certificates, consents, orders, approvals and other authorizations from, and has made all declarations and filings with, all Governmental Authorities, presently required or necessary to own or lease, as the case may be, and to operate its properties and to carry on its businesses as now or proposed to be conducted as described in the Disclosure Package and the Prospectus (“Permits”), except where the failure to possess such Permits would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; and none of the Company or its subsidiaries has received any written notice of any proceeding relating to revocation or modification of any such Permit, except where such revocation or modification would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(aa) The Company and each of its subsidiaries maintain a consolidated system of internal accounting controls sufficient to provide reasonable assurance that (i) material transactions are executed in accordance with management’s general or

specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. The Company and its subsidiaries’ internal controls over financial reporting are effective and the Company and its subsidiaries are not aware of any material weaknesses in their internal controls over financial reporting.

(bb) The Company and its subsidiaries maintain consolidated “disclosure controls and procedures” (as such term is defined in Rule 13a-15(e) under the Exchange Act); such disclosure controls and procedures are effective.

(cc) The Company has not taken, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(dd) Except in each case as would not reasonably be expected, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, the Company and its subsidiaries are (i) in compliance with any and all applicable U.S. or non-U.S. federal, state and local laws and regulations relating to health and safety, or the pollution or the protection of the environment or hazardous or toxic substances of wastes, pollutants or contaminants (“Environmental Laws”), (ii) has received and is in compliance with all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct its respective businesses and (iii) has not received written notice of any actual or potential liability for damages to natural resources or the investigation or remediation of any disposal, release or existence of hazardous or toxic substances or wastes, pollutants or contaminants, in each case except where such non-compliance with Environmental Laws, failure to receive and comply with required permits, licenses or other approvals, or liability would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. Neither the Company nor any of its subsidiaries has been named in writing as a “potentially responsible party” under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended, or any similar U.S. or non-U.S. state or local Environmental Laws or regulation requiring the Company or any of its subsidiaries to investigate or remediate any pollutants or contaminants, except where such requirements would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, whether or not arising from transactions in the ordinary course of business.

(ee) To the knowledge of the Company and its subsidiaries, (i) each of the Company and its subsidiaries are in compliance with applicable health care laws, including without limitation, the federal Anti-kickback Statute (42 U.S.C. § 1320a-7b(b)), the Anti-Inducement Law (42 U.S.C. § 1320a-7a(a)(5)), the civil False Claims Act (31 U.S.C. §§ 3729 et seq.), the administrative False Claims Law (42 U.S.C. § 1320a-7b(a)), the Health Insurance Portability and Accountability Act of 1996 (42 U.S.C.

§ 1320d et seq.), the Health Information Technology for Economic and Clinical Health Act of 2009 (the “HITECH Act”), the exclusion laws (42 U.S.C. § 1320a-7), the Food Drug and Cosmetic Act (21 U.S.C. §§ 301 et seq.), the Medicare Program (Title XVIII of the Social Security Act), the Medicaid Program (Title XIX of the Social Security Act), the Controlled Substances Act (21 U.S.C. §§ 801 et seq.), and any comparable state or local Laws, and the regulations promulgated pursuant to such Laws, each as amended from time to time (each, a “Health Care Law”), and (ii) neither the Company nor its subsidiaries have received written notice of any pending or threatened claim, suit, proceeding, hearing, enforcement, audit, investigation, arbitration or other action from the FDA, DEA or any other applicable Governmental Authority, alleging that any operation or activity of the Company or its subsidiaries is in violation of any applicable Health Care Law, and neither the Company nor its subsidiaries is a party to any corporate integrity agreements, monitoring agreements, consent decrees, settlement orders, or similar agreements with or imposed by any Governmental Authority, except, in the case of both clauses (i) and (ii), for such non-compliance, violation, claim, suit, proceeding or other action as would not individually or in the aggregate reasonably be expected to have a Material Adverse Effect.

(ff) Each of the Company and its subsidiaries owns, or is licensed under, and has the right to use, all patents, patent rights, licenses, inventions, copyrights, know-how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), trademarks, service marks, domain names and trade names (collectively, “Intellectual Property”) necessary for the conduct of its businesses. To the knowledge of the Company, no claims or notices of any potential claim have been asserted by any person challenging the use of any such Intellectual Property by the Company or any of its subsidiaries or questioning the validity or effectiveness of any Intellectual Property or any license or agreement related thereto, other than any claims that, if successful, would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(gg) Neither the Company nor any of its subsidiaries have a “pension plan” (as defined in Section 3(2) of the United States Employee Retirement Income Security Act of 1974, as amended (“ERISA”)) or any other employee benefit plan that is subject to ERISA.

(hh) There is and has been no failure on the part of the Company and any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the Sarbanes-Oxley Act of 2002, as amended, and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”), including Section 402 relating to loans and Sections 302 and 906 relating to certifications, in each case solely to the extent applicable to the Company.

(ii) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries is aware of or has taken any action, directly or indirectly, that would result in a violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation,

making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Company, its subsidiaries and, to the knowledge of the Company, its affiliates have conducted their businesses in compliance with the FCPA and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

(jj) The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements and the money laundering statutes and the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

(kk) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries (i) is currently subject to any sanctions administered or imposed by the United States (including any administered or enforced by the Office of Foreign Assets Control of the U.S. Treasury Department, the U.S. Department of State, or the Bureau of Industry and Security of the U.S. Department of Commerce), the United Nations Security Council, the European Union, or the United Kingdom (including sanctions administered or controlled by Her Majesty’s Treasury) (collectively, “Sanctions” and such persons, “Sanction Persons”) or (ii) will, directly or indirectly, use the proceeds of this offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person in any manner that will result in a violation of any economic Sanctions by, or could result in the imposition of Sanctions against, any person (including any person participating in the offering, whether as underwriter, advisor, investor or otherwise).

(ll) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries, is a person that is, or is 50% or more owned or otherwise controlled by a person that is: (i) the subject of any Sanctions; or (ii) located, organized or resident in a country or territory that is, or whose government is, the subject of Sanctions that broadly prohibit dealings with that country or territory (currently, Cuba, Iran, North Korea, Sudan, and Syria) (collectively, “Sanctioned Countries” and each, a “Sanctioned Country”).

(mm) Except as has been disclosed to the Underwriters or is not material to the analysis under any Sanctions, neither the Company nor any of its subsidiaries has engaged in any dealings or transactions with or for the benefit of a Sanctioned Person, or

with or in a Sanctioned Country, in the preceding 3 years, nor does the Company or any of its subsidiaries have any plans to increase its dealings or transactions with Sanctioned Persons, or with or in Sanctioned Countries.

Any written certificate signed by any officer of the Company and delivered to the Underwriters or counsel for the Underwriters in connection with the offering of the Securities shall be deemed a representation and warranty by the Company, as to matters covered thereby and as of the date thereof, to each Underwriter. Notwithstanding anything to the contrary in this Agreement, the representations and warranties set forth in this Section 1 are made only as of the date hereof and the Closing Date.

2. Purchase and Sale. (a) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company, at a purchase price of $7.76 per share, the amount of the Securities set forth opposite such Underwriter’s name in Schedule I hereto.

3. Delivery and Payment. Delivery of and payment for the Securities shall be made at 10:00 AM, New York City time, on September 14, 2016, or at such time on such later date not more than three Business Days after the foregoing date as the Underwriters shall designate, which date and time may be postponed by agreement between the Underwriters and the Company or as provided in Section 9 hereof (such date and time of delivery and payment for the Securities being herein called the “Closing Date”). Delivery of the Securities shall be made to the Underwriters for the respective accounts of the several Underwriters against payment by the several Underwriters through the Underwriters of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to an account specified by the Company. Delivery of the Securities shall be made through the facilities of DTC unless the Underwriters shall otherwise instruct.

4. Offering by Underwriters. It is understood that the several Underwriters propose to offer the Securities for sale to the public as set forth in the Prospectus.

5. Agreements.

The Company agrees with the several Underwriters that:

(a) Prior to the termination of the offering of the Securities, the Company will not file any amendment of the Registration Statement or supplement (including the Prospectus or any Preliminary Prospectus) to the Base Prospectus or any Rule 462(b) Registration Statement unless the Company has furnished you a copy for your review prior to filing and will not file any such proposed amendment or supplement to which you reasonably object. The Company will cause the Prospectus, properly completed, and any supplement thereto to be filed in a form approved by the Underwriters with the Commission pursuant to the applicable paragraph of Rule 424(b) within the time period prescribed and will provide evidence satisfactory to the Underwriters of such timely filing. The Company will promptly advise the Underwriters (i) when the Prospectus, and

any supplement thereto, shall have been filed (if required) with the Commission pursuant to Rule 424(b) or when any Rule 462(b) Registration Statement shall have been filed with the Commission, (ii) when, prior to termination of the offering of the Securities, any amendment to the Registration Statement shall have been filed or become effective, (iii) of any request by the Commission or its staff for any amendment of the Registration Statement, or any Rule 462(b) Registration Statement, or for any supplement to the Prospectus or for any additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any notice objecting to its use or the institution or threatening of any proceeding for that purpose and (v) of the receipt by the Company of any notification with respect to the suspension of the qualification of the Securities for sale in any jurisdiction or the institution or threatening of any proceeding for such purpose. The Company will use its commercially reasonable efforts to prevent the issuance of any such stop order or the occurrence of any such suspension or objection to the use of the Registration Statement and, upon such issuance, occurrence or notice of objection, to obtain as soon as possible the withdrawal of such stop order or relief from such occurrence or objection, including, if necessary, by filing an amendment to the Registration Statement or a new registration statement and using its commercially reasonable efforts to have such amendment or new registration statement declared effective as soon as practicable.

(b) If, at any time prior to the filing of the Prospectus pursuant to Rule 424(b), any event occurs as a result of which the Disclosure Package would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made at such time not misleading, the Company will (i) notify promptly the Underwriters so that any use of the Disclosure Package may cease until it is amended or supplemented; (ii) amend or supplement the Disclosure Package to correct such statement or omission; and (iii) supply any amendment or supplement to you in such quantities as you may reasonably request.

(c) If, at any time when a prospectus relating to the Securities is required to be delivered under the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), any event occurs as a result of which the Prospectus as then supplemented would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made or the circumstances then prevailing not misleading, or if it shall be necessary to amend the Registration Statement, file a new registration statement or supplement the Prospectus to comply with the Act or the Exchange Act or the respective rules thereunder, including in connection with the use or delivery of the Prospectus, the Company promptly will (i) notify the Underwriters of any such event; (ii) prepare and file with the Commission, subject to the second sentence of paragraph (a) of this Section 5, an amendment or supplement or new registration statement which will correct such statement or omission or effect such compliance; (iii) use its best efforts to have any amendment to the Registration Statement or new registration statement declared effective as soon as practicable in order to avoid any disruption in use of the Prospectus and (iv) supply any supplemented Prospectus to you in such quantities as you may reasonably request.

(d) As soon as practicable, the Company will make generally available to its security holders and to the Underwriters an earnings statement or statements of the Company and its subsidiaries which will satisfy the provisions of Section 11(a) of the Act and Rule 158.

(e) The Company will furnish to the Underwriters and counsel for the Underwriters, without charge, signed copies of the Registration Statement (including exhibits thereto) and to each other Underwriter a copy of the Registration Statement (without exhibits thereto) and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), as many copies of each Preliminary Prospectus, the Prospectus and each Issuer Free Writing Prospectus and any supplement thereto as the Underwriters may reasonably request. The Company will pay the expenses of printing or other production of all documents relating to the offering.

(f) The Company will arrange, if necessary, for the qualification of the Securities for sale under the laws of such jurisdictions as the Underwriters may reasonably designate after consultation with the Company and will use its commercially reasonable efforts to maintain such qualifications in effect so long as required for the distribution of the Securities; provided that in no event shall the Company be obligated to qualify to do business in any jurisdiction where it is not now so qualified or to take any action that would subject it to service of process in suits, other than those arising out of the offering or sale of the Securities, or subject it to taxation, in each case in any jurisdiction where it is not now so subject.

(g) The Company will not, without the prior written consent of Credit Suisse Securities (USA) LLC, offer, sell, contract to sell, pledge, or otherwise dispose of, (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash settlement or otherwise) by the Company or any affiliate of the Company or any person in privity with the Company or any affiliate of the Company) directly or indirectly, including the filing (or participation in the filing) of a registration statement with the Commission in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Exchange Act, any other shares of Common Stock or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock (“Lock-up Securities”), or publicly announce an intention to effect any such transaction, in each case, for a period of 60 days after the date of the Underwriting Agreement, provided, however, that (i) the Company may issue and sell Common Stock or any securities convertible into, or exercisable for, shares of Common Stock pursuant to any employee stock option plan, incurrence plan, stock ownership plan or dividend reinvestment plan of the Company in effect at the Execution Time, (ii) the Company may issue Common Stock issuable upon the conversion of securities or the exercise of warrants outstanding at the Execution Time and (iii) issue and sell the securities to be sold hereunder, (iv) the Company may file one or more registration statements on Form S-8 with respect to an employee stock plan described in the Disclosure Package, (v) the Company may pledge any shares of the capital stock of any of the subsidiaries of the Company in connection with the incurrence

of any new or refinanced indebtedness and (vi) the Company may offer, issue or sell Lock-up Securities as consideration or partial consideration for an acquisition or in connection with a strategic investment (including a joint venture or partnership), provided that (x) the aggregate number of shares of Common Stock represented by the Lock-up Securities offered, issued or sold pursuant to this clause (vi) does not exceed 10% of the number of shares of Common Stock outstanding immediately after the issuance and sale of the Securities pursuant to this Agreement (assuming full conversion, exercise and exchange of such Lock-up Securities) and (y) each recipient of any Lock-up Securities issued or sold pursuant to either clauses (v) or (vi) above executes and delivers to Credit Suisse Securities (USA) LLC prior to such issuance or sale (as the case may be) an agreement having substantially the same terms as the lock-up letters described in Section 6(j) of this Agreement.

(h) [Reserved.]

(i) The Company will not take, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(j) The Company agrees to pay the costs and expenses relating to the following matters: (i) the preparation, printing or reproduction and filing with the Commission of the Registration Statement (including financial statements and exhibits thereto), each Preliminary Prospectus, the Prospectus and each Issuer Free Writing Prospectus, and each amendment or supplement to any of them; (ii) the printing (or reproduction) and delivery (including postage, air freight charges and charges for counting and packaging) of such copies of the Registration Statement, each Preliminary Prospectus, the Prospectus and each Issuer Free Writing Prospectus, and all amendments or supplements to any of them, as may, in each case, be reasonably requested for use in connection with the offering and sale of the Securities; (iii) the preparation, printing, authentication, issuance and delivery of certificates for the Securities, including any stamp or transfer taxes in connection with the original issuance and sale of the Securities; (iv) the printing (or reproduction) and delivery of this Agreement, any blue sky memorandum and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Securities; (v) the registration of the Securities under the Exchange Act and the listing of the Securities on the Nasdaq Global Market; (vi) any registration or qualification of the Securities for offer and sale under the securities or blue sky laws of the several states (including filing fees and the reasonable fees and expenses of counsel for the Underwriters relating to such registration and qualification); (vii) any filings required to be made with the Financial Industry Regulatory Authority, Inc. (“FINRA”) (including filing fees and the reasonable fees and expenses of counsel for the Underwriters relating to such filings); provided, that the reasonable fees of counsel for the Underwriters relating to subclauses (vi) and (vii) of this Section 5(j) shall not exceed $27,500 in the aggregate; (viii) the travel, transportation and other expenses incurred by or on behalf of Company representatives in connection with presentations to prospective purchasers of the Securities; provided that Underwriters will pay all costs of air and ground transportation of the Underwriters’ representatives in

connection with the presentations to prospective purchasers of the Securities and the cost of any aircraft chartered for the road show shall be borne 50% by the Underwriters; (ix) the fees and expenses of the Company’s accountants and the fees and expenses of counsel (including local and special counsel) for the Company; and (x) all other costs and expenses incident to the performance by the Company of its obligations hereunder.

(k) The Company agrees that, unless it has or shall have obtained the prior written consent of the Underwriters, and each Underwriter, severally and not jointly, agrees with the Company that, unless it has or shall have obtained, as the case may be, the prior written consent of the Company, it has not made and will not make any offer relating to the Securities that would constitute an Issuer Free Writing Prospectus or that would otherwise constitute a “free writing prospectus” (as defined in Rule 405) required to be filed by the Company with the Commission or retained by the Company under Rule 433; provided that the prior written consent of the parties hereto shall be deemed to have been given in respect of the Free Writing Prospectuses included in Schedule II hereto and any electronic road show. Any such free writing prospectus consented to by the Underwriters or the Company is hereinafter referred to as a “Permitted Free Writing Prospectus.” The Company agrees that (x) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus and (y) it has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

(l) The Company will notify promptly the Underwriters if the Company ceases to be an Emerging Growth Company at any time prior to the later of (a) completion of the distribution of the Securities within the meaning of the Securities Act and (b) completion of the 60-day restricted period referred to in Section 5(g) hereof.

(m) If at any time following the distribution of any Written Testing-the-Waters Communication, any event occurs as a result of which such Written Testing-the-Waters Communication would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made at such time not misleading, the Company will (i) notify promptly the Underwriters so that use of the Written Testing-the-Waters Communication may cease until it is amended or supplemented; (ii) amend or supplement the Written Testing-the-Waters Communication to correct such statement or omission; and (iii) supply any amendment or supplement to the Underwriters in such quantities as may be reasonably requested.

6. Conditions to the Obligations of the Underwriters. The obligations of the Underwriters to purchase the Securities shall be subject to the condition that all representations and warranties on the part of the Company contained herein as of the Execution Time and the Closing Date pursuant to Section 3 hereof, if applicable, and any statements of the Company made in any certificates pursuant to the provisions hereof, are true and correct in all material respects (except to the extent already qualified by materiality or Material Adverse Effect, in which case, such representations and warranties shall be true and correct in all respects), the condition that the Company shall have performed, in all material respects, all of its obligations hereunder and to the following additional conditions:

(a) The Prospectus, and any supplement thereto, have been filed in the manner and within the time period required by Rule 424(b); any material required to be filed by the Company pursuant to Rule 433(d) under the Act shall have been filed with the Commission within the applicable time periods prescribed for such filings by Rule 433; and no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use shall have been issued and no proceedings for that purpose shall have been instituted or threatened.

(b) The Company shall have requested and caused Ropes & Gray LLP, counsel for the Company, to have furnished to the Underwriters their opinion and negative assurance letter, dated the Closing Date and addressed to the Underwriters, substantially in the forms reasonably satisfactory to the Underwriters.

(c) The Underwriters shall have received from Latham & Watkins LLP, counsel for the Underwriters, an opinion or opinions, dated the Closing Date and addressed to the Underwriters, with respect to the issuance and sale of the Securities, the Registration Statement, the Disclosure Package, the Prospectus (together with any supplement thereto) and other related matters as the Underwriters may reasonably require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(d) The Company shall have furnished to the Underwriters a certificate of the Company, signed by the Chief Executive Officer and the President, and the principal financial or accounting officer of the Company, dated the Closing Date, to the effect that the signers of such certificate have carefully examined the Registration Statement, the Disclosure Package, the Prospectus and any amendment or supplement thereto, as well as each electronic road show used in connection with the offering of the Securities, and this Agreement and that:

(e) The Company shall have requested and caused Deloitte & Touche LLP to have furnished to the Underwriters, at the Execution Time and at the Closing Date, letters, dated respectively as of the Execution Time and as of the Closing Date, in form and substance reasonably satisfactory to the Underwriters containing statements and information of the type ordinarily included in accountants “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Preliminary Prospectus and the Prospectus.

(f) Subsequent to the Execution Time or, if earlier, the dates as of which information is given in the Registration Statement (exclusive of any amendment thereof) and the Prospectus (exclusive of any amendment or supplement thereto), there shall not have been (i) any change or decrease specified in the letter or letters referred to in paragraph (e) of this Section 6 or (ii) any change, or any development involving a prospective change, in or affecting the condition (financial or otherwise), earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Disclosure Package and the Prospectus (exclusive of any amendment or supplement thereto) the effect of which, in any case referred to in clause (i) or (ii) above, is, in the sole judgment of the Underwriters, so material and adverse as to make it impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated by the Registration Statement (exclusive of any amendment thereof), the Disclosure Package and the Prospectus (exclusive of any amendment or supplement thereto).

(g) Prior to the Closing Date, the Company shall have furnished to the Underwriters such further customary information, certificates and documents as the Underwriters may reasonably request.

(h) The Securities shall have been listed and admitted and authorized for trading on the Nasdaq Global Market, and satisfactory evidence of such actions shall have been provided to the Underwriters.

(i) At the Execution Time, the Company shall have furnished to the Underwriters a letter substantially in the form of Exhibit A hereto from each officer and director of the Company and the stockholders in each case listed on Schedule IV hereto addressed to the Underwriters.

If any of the conditions specified in this Section 6 shall not have been fulfilled when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be reasonably satisfactory in form and substance to the Underwriters and counsel for the Underwriters, this Agreement and all obligations of the Underwriters hereunder may be canceled at, or at any time prior to, the Closing Date by the Underwriters. Notice of such cancellation shall be given to the Company in writing or by telephone or facsimile confirmed in writing.

The documents required to be delivered by this Section 6 shall be delivered at the office of Latham & Watkins, counsel for the Underwriters, at 805 Third Ave., New York, New York 10022, on the Closing Date.

7. Reimbursement of Underwriters’ Expenses. If the sale of the Securities provided for herein is not consummated because any condition to the obligations of the Underwriters set forth in Section 6 hereof is not satisfied, because of any termination pursuant to Section 10 hereof or because of any refusal, inability or failure on the part of the Company to perform any agreement herein or comply with any provision hereof other than by reason of a default by any of the Underwriters, the Company will reimburse the Underwriters severally through the Underwriters on demand for all reasonable and documented out-of-pocket expenses (including reasonable fees and disbursements of counsel) that shall have been reasonably incurred by them in connection with the proposed purchase and sale of the Securities.

8. Indemnification and Contribution. (a) The Company agrees to indemnify and hold harmless each Underwriter, the directors, officers, employees and agents of each Underwriter and each person who controls any Underwriter within the meaning of either the Act or the Exchange Act against any and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other Federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the registration statement for the registration of the Securities as originally filed or in any amendment thereof, or in the Base Prospectus, any Preliminary Prospectus, or any other preliminary prospectus supplement relating to the Securities, the Prospectus, any Issuer Free Writing Prospectus, or any Written Testing the Waters Communication or in any amendment thereof or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary in order to make the statements therein not misleading, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made therein in reliance upon and in conformity with written information furnished to the Company by the Underwriters, specifically for inclusion therein. This indemnity agreement will be in addition to any liability which the Company may otherwise have.

(b) Each Underwriter severally and not jointly agrees to indemnify and hold harmless the Company, each of its directors, each of its officers who signs the Registration

Statement, and each person who controls the Company within the meaning of either the Act or the Exchange Act, to the same extent as the foregoing indemnity from the Company to each Underwriter, but only with reference to written information relating to such Underwriter furnished to the Company by or on behalf of such Underwriter through the Underwriters specifically for inclusion in the documents referred to in the foregoing indemnity. This indemnity agreement will be in addition to any liability which any Underwriter may otherwise have. The Company acknowledges that the statements set forth (i) in the last paragraph of the cover page regarding delivery of the Securities and, under the heading “Underwriting” or “Plan of Distribution”, (ii) the list of Underwriters and their respective participation in the sale of the Securities, (iii) the sentences related to concessions and reallowances and (iv) the paragraph related to stabilization, syndicate covering transactions and penalty bids in the Preliminary Prospectus and the Prospectus constitute the only information furnished in writing by or on behalf of the several Underwriters for inclusion in the Preliminary Prospectus, the Prospectus or any Issuer Free Writing Prospectus.

(c) Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above. The indemnifying party shall be entitled to appoint counsel of the indemnifying party’s choice at the indemnifying party’s expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be reasonably satisfactory to the indemnified party. Notwithstanding the indemnifying party’s election to appoint counsel to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel (which, if the Company is the indemnifying party, shall be limited to one such separate counsel for all indemnified parties, and to the extent applicable, one local counsel per jurisdiction for all indemnified parties) if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest, (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, (iii) the indemnifying party shall not have employed counsel reasonably satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action or (iv) the indemnifying party shall authorize the indemnified party to employ separate counsel at the expense of the indemnifying party. An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder

(whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding.

(d) In the event that the indemnity provided in paragraph (a), (b) or (c) of this Section 8 is unavailable to or insufficient to hold harmless an indemnified party for any reason, the Company and the Underwriters severally agree to contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending the same) (collectively “Losses”) to which the Company and one or more of the Underwriters may be subject in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and by the Underwriters on the other from the offering of the Securities; provided, however, that in no case shall any Underwriter (except as may be provided in any agreement among underwriters relating to the offering of the Securities) be responsible for any amount in excess of the underwriting discount or commission applicable to the Securities purchased by such Underwriter hereunder. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the Company and the Underwriters severally shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such Losses as well as any other relevant equitable considerations. Benefits received by the Company shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by it and benefits received by the Underwriters shall be deemed to be equal to the total underwriting discounts and commissions, in each case as set forth on the cover page of the Final Prospectus. Relative fault shall be determined by reference to, among other things, whether any untrue or any alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the Company on the one hand or the Underwriters on the other, the intent of the parties and their relative knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The Company and the Underwriters agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation which does not take account of the equitable considerations referred to above. Notwithstanding the provisions of this paragraph (e), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 8, each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, officer, employee, and agent of an Underwriter shall have the same rights to contribution as such Underwriter, and each person who controls the Company within the meaning of either the Act or the Exchange Act, each officer of the Company who shall have signed the Registration Statement and each director of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (e).

9. Default by an Underwriter. If there is more than one Underwriter party to this Agreement and any one or more Underwriters shall fail to purchase and pay for any of the Securities agreed to be purchased by such Underwriter or Underwriters hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Underwriters shall be obligated severally to take up and pay for (in the respective proportions which the amount of Securities set forth opposite their names in

Schedule I hereto bears to the aggregate amount of Securities set forth opposite the names of all the remaining Underwriters) the Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate amount of Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of the aggregate amount of Securities set forth in Schedule I hereto, the remaining Underwriters shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Securities, and if such nondefaulting Underwriters do not purchase all the Securities, this Agreement will terminate without liability to any nondefaulting Underwriter or the Company. In the event of a default by any Underwriter as set forth in this Section 9, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Underwriters shall determine in order that the required changes in the Registration Statement and the Prospectus or in any other documents or arrangements may be effected. Nothing contained in this Agreement shall relieve any defaulting Underwriter of its liability, if any, to the Company and any nondefaulting Underwriter for damages occasioned by its default hereunder. For the avoidance of doubt, to the extent there is only a single Underwriter (as contemplated in the first paragraph of this Agreement), the provisions of this Section 9 shall be deemed to be deleted from this Agreement and shall have no force or effect.

10. Termination. This Agreement shall be subject to termination in the absolute discretion of the Underwriters, by written notice given to the Company prior to delivery of and payment for the Securities, if at any time prior to such delivery and payment (i) (a) trading in the Company’s Common Stock shall have been suspended by the Commission or the Nasdaq Global Market or (b) trading in securities generally on the Nasdaq Global Market shall have been suspended or limited or minimum prices shall have been established on such exchange, (ii) a banking moratorium shall have been declared either by Federal or New York State authorities or (iii) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war, or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Underwriters, impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated by the Preliminary Prospectus or the Prospectus (exclusive of any amendment or supplement thereto).

11. Representations and Indemnities to Survive. The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers and of the Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by any Underwriter or the Company or any of the officers, directors, employees, agents or controlling persons referred to in Section 8 hereof, and will survive delivery of and payment for the Securities. The provisions of Sections 7 and 8 hereof shall survive the termination or cancellation of this Agreement.

12. Notices. All communications hereunder will be in writing and effective only on receipt, and, if sent to the Underwriters, will be mailed, delivered or telefaxed to Credit Suisse Securities (USA) LLC General Counsel (fax no.: (212)  ###-###-####) and confirmed to the General Counsel, Credit Suisse Securities (USA) LLC, at Eleven Madison Avenue, New York, New York 10010, Attention: IBCM-Legal and Jefferies LLC, 520 Madison Avenue, New York, New York 10022, Attention: General Counsel (fax no.: (646)  ###-###-####); or, if sent to the Company, will be mailed, delivered or telefaxed to Lantheus Holdings, Inc., 331 Treble Cove Road, North Billerica, Massachusetts 01862, Attention: Michael P. Duffy, Senior Vice President, General Counsel and Secretary.

13. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers, directors, employees, agents and controlling persons referred to in Section 8 hereof, and no other person will have any right or obligation hereunder.

14. No fiduciary duty. The Company hereby acknowledges that (a) the purchase and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the Underwriters and any affiliate through which it may be acting, on the other, (b) the Underwriters are acting as principal and not as an agent or fiduciary of the Company and (c) the Company’s engagement of the Underwriters in connection with the offering and the process leading up to the offering is as independent contractors and not in any other capacity. Furthermore, the Company agrees that it is solely responsible for making their own judgments in connection with the offering (irrespective of whether any of the Underwriters has advised or is currently advising the Company on related or other matters). The Company agrees that it will not claim that the Underwriters have rendered advisory services of any nature or respect, or owe an agency, fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

15. Integration. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or any of them, with respect to the subject matter hereof.

16. Applicable Law. This Agreement (and all claims, controversies and causes of action relating hereto or arising hereunder or in connection herewith, regardless of whether asserted in contract, tort or otherwise) will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York.

17. Waiver of Jury Trial. The Company and the Underwriters hereby irrevocably waive, 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 Agreement or the transactions contemplated hereby.

18. Counterparts. This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement.

19. Headings. The section headings used herein are for convenience only and shall not affect the construction hereof.

20. Definitions. The terms that follow, when used in this Agreement, shall have the meanings indicated.

“Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Base Prospectus” shall mean the base prospectus referred to in paragraph 1(a) above contained in the Registration Statement at the Execution Time.

“Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in New York City.

“Commission” shall mean the Securities and Exchange Commission.

“Disclosure Package” shall mean (i) the Base Prospectus, (ii) the Preliminary Prospectus used most recently prior to the Execution Time, (iii) the price to the public and the number of Securities, in each case as included on the cover page of the Prospectus, (iv) the Issuer Free Writing Prospectuses, if any, identified in Schedule II hereto, and (v) any other Free Writing Prospectus that the parties hereto shall hereafter expressly agree in writing to treat as part of the Disclosure Package.

“Effective Date” shall mean each date and time that the Registration Statement, any post-effective amendment or amendments thereto and any Rule 462(b) Registration Statement became or becomes effective.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Execution Time” shall mean the date and time that this Agreement is executed and delivered by the parties hereto.

“Free Writing Prospectus” shall mean a free writing prospectus, as defined in Rule 405.

“Issuer Free Writing Prospectus” shall mean an issuer free writing prospectus, as defined in Rule 433.

“Preliminary Prospectus” shall mean any preliminary prospectus supplement to the Base Prospectus referred to in paragraph 1(a) above which is used prior to the filing of the Prospectus, together with the Base Prospectus.

“Prospectus” shall mean the prospectus relating to the Securities that is first filed pursuant to Rule 424(b) after the Execution Time, together with the Base Prospectus.

“Registration Statement” shall mean the registration statement referred to in paragraph 1(a) above, including exhibits and financial statements and any prospectus supplement relating to the Securities that is filed with the Commission pursuant to Rule 424(b) and deemed part of such registration statement pursuant to Rule 430A, as amended on each Effective Date and, in the event any post-effective amendment thereto or any Rule 462(b) Registration Statement becomes effective prior to the Closing Date, shall also mean such registration statement as so amended or such Rule 462(b) Registration Statement, as the case may be.

“Rule 158”, “Rule 163”, “Rule 164”, “Rule 172”, “Rule 405”, “Rule 415”, “Rule 424”, “Rule 430A” and “Rule 433” refer to such rules under the Act.

“Rule 430A Information” shall mean information with respect to the Securities and the offering thereof permitted to be omitted from the Registration Statement when it becomes effective pursuant to Rule 430A.

“Rule 462(b) Registration Statement” shall mean a registration statement and any amendments thereto filed pursuant to Rule 462(b) relating to the offering covered by the registration statement referred to in Section 1(a) hereof

If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this letter and your acceptance shall represent a binding agreement among the Company and the several Underwriters.

SCHEDULE I

SCHEDULE II

Schedule of Free Writing Prospectuses included in the Disclosure Package

None.

SCHEDULE III

Schedule of Written Testing-the-Waters Communication

None.

SCHEDULE IV

List of Lock-Up Parties

Directors

Brian Markison

David Burgstahler

James C. Clemmer

Samuel Leno

Dr. Frederick Robertson

Dr. Derace Schaffer

Sriram Venkataraman

Officers

Mary Anne Heino

Jack Crowley

William Dawes

Michael Duffy

Timothy Healey

Dr. Cesare Orlandi

Stockholders

Avista Capital Partners (Offshore), LP

Avista Capital Partners, LP

ACP-Lantern Co-Invest, LLC

Form of Lock-Up Agreement

Lantheus Holdings, Inc.

Lock-up Agreement for the

Public Offering of Common Stock

                    , 2016

Credit Suisse Securities (USA) LLC

Jefferies LLC

Ladies and Gentlemen:

This letter is being delivered to you in connection with the proposed Underwriting Agreement (the “Underwriting Agreement”), between Lantheus Holdings, Inc., a Delaware corporation (the “Company”), and each of you as representatives of a group of Underwriters named therein, relating to an underwritten public offering of Common Stock, $0.01 par value (the “Common Stock”), of the Company (the “Offering”).

In order to induce you and the other Underwriters to enter into the Underwriting Agreement, the undersigned will not, without the prior written consent of Credit Suisse Securities (USA) LLC, offer, sell, contract to sell, pledge or otherwise dispose of, (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition by the undersigned or any affiliate of the undersigned), directly or indirectly, including the filing (or participation in the filing) of a registration statement with the Securities and Exchange Commission in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations of the Securities and Exchange Commission promulgated thereunder with respect to, any shares of capital stock of the Company or any securities convertible into, or exercisable or exchangeable for such capital stock, or publicly announce an intention to effect any such transaction, for a period from the date hereof until 60 days after the date of the Underwriting Agreement (the “Lock-Up Period”).

If the undersigned is an officer or director of the Company, Credit Suisse Securities (USA) LLC agrees that, at least three business days before the effective date of any release or waiver of the foregoing restrictions in connection with a transfer of shares of Common Stock, Credit Suisse Securities (USA) LLC on behalf of the Underwriters will notify the Company of the impending release or waiver. The provisions of this paragraph will not apply if (a) the release or waiver is effected solely to permit a transfer not for consideration and (b) the transferee has agreed in writing to be bound by the same terms described in this letter agreement that are applicable to the transferor to the extent and for the duration that such terms remain in effect at the time of the transfer.

Notwithstanding the foregoing, the undersigned may transfer any shares of Common Stock or any securities convertible into, or exercisable or exchangeable for such Common Stock:

(i) as a bona fide gift or gifts;

(ii) to any beneficiary of the undersigned pursuant to a will, other testamentary document or intestate succession to the legal representatives, heir, beneficiary or immediate family member of the undersigned;

(iii) to any trust, partnership, limited liability company or other entity for the direct or indirect benefit of the undersigned or the immediate family of the undersigned;

(iv) to any immediate family member or other dependent;

(v) as a distribution to subsidiaries, limited partners, members or stockholders of the undersigned;

(vi) to the undersigned’s affiliates or to any investment fund or other entity controlled or managed by, or under common control or management as, the undersigned;

(vii) to a nominee or custodian of a person or entity to whom a disposition or transfer would be permissible under clauses (i) through (vi) above;

(viii) pursuant to an order of a court or regulatory agency or to comply with any regulations related to the Undersigned’s ownership of the Common Stock; provided that in the case of any transfer or distribution pursuant to this clause, any filing under Section 16(a) of the Exchange Act reporting a reduction in beneficial ownership of shares of Common Stock, shall state that such transfer is pursuant to an order of a court or regulatory agency or to comply with any regulations related to the ownership of the Common Stock unless such a statement would be prohibited by any applicable law, regulation or order of a court or regulatory authority, unless such a statement would be prohibited by any applicable law, regulation or order of a court or regulatory agency;

(ix) to the Company or its affiliates upon death, disability or termination of employment, in each case, of the undersigned;

(x) to the Company or its affiliates (A) deemed to occur upon the cashless exercise of options or (B) for the primary purpose of paying the exercise price of such options or for paying taxes (including estimated taxes) due as a result of the exercise of such options or as a result of the vesting of Common Stock pursuant to employee benefit plans disclosed in the Registration Statement; provided that in the case of any transfer or distribution pursuant to this clause, except as a result of the vesting of such Common Stock, no filing under Section 16(a) of the Exchange Act (other than a filing on Form 5), reporting a reduction in beneficial ownership of shares of Stock, shall be required or shall be voluntarily made during the Stockholder Lock-Up Period;

(xi) in connection with transactions by any person other than the Company relating to Securities acquired in open market transactions after the completion of the Offering; or

(xii) with the prior written consent of Credit Suisse Securities (USA) LLC on behalf of the Underwriters;

provided that, (1) in the case of each transfer or distribution pursuant to clauses (i) through (vii) above, each donee, trustee, distributee or transferee, as the case may be, agrees to be bound in writing by the restrictions set forth herein, (2) in the case of each transfer or distribution pursuant to clauses (v) through (vii) above, shall not involve a disposition for value and (3) in the case of each transfer or distribution

pursuant to clauses (i), (iii) through (vii) and (xi) above, no filing under Section 16(a) of the Exchange Act (other than filing on Form 5 made after the expiration of the Lock-Up Period) reporting a reduction in beneficial ownership of shares of Common Stock, shall be required or shall be voluntarily made during the Lock-Up Period. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

The restrictions described in this Lock-Up Agreement shall not apply to the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act, provided that no transfers occur under such plan during the Lock-Up Period and no public announcement or filing shall be required or voluntarily made by any person in connection therewith until after the expiration of the Lock-Up Period.

This Lock-Up Agreement shall be terminated and the undersigned shall be released from its obligations hereunder upon the earlier of (i) the date the Registration Statement filed with the SEC with respect to the offering is withdrawn, (ii) the date on which for any reason the Underwriting Agreement is terminated (other than the provisions thereof that survive termination) prior to payment for and delivery of the Shares to be sold thereunder or (iii) October 8, 2016, if the Offering is not completed by such date.

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