Exhibit 10.1

EMPLOYMENT AGREEMENT

THIS EMPLOYMENT AGREEMENT (the “Agreement”), made this 1st day of March 2007, is entered into by Sepracor Inc., a Delaware corporation with its principal place of business at 84 Waterford Drive, Marlborough, Massachusetts 01752-7231(the “Company”), and Adrian Adams, residing at                                         (the “Executive”).

The Company desires to employ the Executive and the Executive desires to be employed by the Company.  In consideration of the mutual covenants and promises contained herein, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by the parties hereto, the parties agree as follows:

1.                                        Term of Employment .  The Company hereby agrees to employ the Executive and the Executive hereby accepts employment with the Company, upon the terms set forth in this Agreement, for the period commencing on March 1, 2007 (the “Commencement Date”) and ending on March 1, 2012 (the “Term”) .  Notwithstanding the foregoing, the Term shall be extended automatically without further action by either party by one (1) additional year (added to the end of the Term) on each succeeding anniversary of March 1, 2012, unless either party shall have served written notice upon the other party at least sixty (60) days preceding the date upon which such Term would end (such period, as it may be extended, the “Employment Period”), unless sooner terminated in accordance with the provisions of Section 4.

2.                                        Title and Capacity .  The Executive shall initially serve as President and Chief Operating Officer of the Company and in that capacity Executive shall report directly to the Chief Executive Officer of the Company and shall, except as permitted

hereby, devote all of his business time and services to the business and affairs of the Company.  The Company acknowledges that it is the present expectation of the Board and the parties hereto that Executive will be elected to the position of Chief Executive Officer within six months of the Commencement Date.  At such time as the Executive is elected to the position of Chief Executive Officer, he shall report directly to the Board and shall assume the duties and responsibilities inherent in such position and such other duties and responsibilities as the Board shall from time to time reasonably assign to him.

Executive shall also perform such other duties consistent with his position at such time as may be reasonably assigned by the Chief Executive Officer (if Executive does not then hold such position) and/or the Board of Directors of the Company (the “Board”) from time to time.  Executive shall serve on the Board and may also serve as a director or officer of any of the Company’s operating subsidiaries if the Executive shall be elected to such position, for no additional compensation or benefits.  The Executive hereby accepts such service and agrees to undertake the duties and responsibilities inherent in such positions.  The Executive agrees to abide by the rules, regulations, instructions, personnel practices and policies of the Company and any changes therein that may be adopted from time to time by the Company.

Notwithstanding anything herein to the contrary, Executive shall be entitled to engage in (a) service on the board of directors of a no more than three other companies, businesses or trade organizations, provided , that , the Executive shall provide the Company prior written notice of his intention to join any such board and provided further that he shall not serve on the board of any entity that competes with the Company, (b) service on the board of directors of not-for-profit or charitable organizations, (c) other

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charitable activities and community affairs and (d) managing his personal investments and affairs, in each case to the extent such activities do not materially interfere with the performance of his duties and responsibilities to the Company.

3.                                        Compensation and Benefits .

3.1                                  Salary .  During the term of this Agreement, the Company agrees to pay to the Executive a base salary at the annualized rate of $800,000 (“Base Salary”) commencing on the Commencement Date.  The Base Salary shall be subject to annual review by the Board but shall not be reduced below $800,000 per annum.  Such salary shall be payable to Executive in bi-weekly installments and in accordance with the Company’s normal payroll procedures.

3.2                                  Bonus .  The Executive shall be eligible for a performance-based annual bonus for each fiscal year of the Term (the “Annual Bonus”).  The Annual Bonus shall be based upon annual quantitative and qualitative performance targets as established by the Board in its sole discretion in accordance with the Company’s bonus plan; provided , that the Executive’s annual bonus level target shall be set at one hundred percent (100%) of Base Salary.  For fiscal year 2007, the Executive shall be entitled to a pro rata guaranteed bonus based on an Annual Bonus of one hundred percent (100%) of his Base Salary.   The Annual Bonus is not earned until the close of business on the last business day of the Company’s fiscal year.  Any Annual Bonus payable hereunder shall be payable, if at all, after the date of the delivery of the audited financial statements for the applicable fiscal year.

3.3                                  Stock and Option Grant .  At the first meeting of the Compensation Committee of the Board of Directors following the Executive’s first day of employment,

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the Company shall grant to the Executive, under the Company’s 2000 Stock Incentive Plan (the “Stock Plan”), 125,000 shares of restricted stock and an option to purchase 500,000 shares of Company stock (the “Initial Grant”).  The terms and conditions of the Initial Grant (other than the exercise price per share, which shall be equal to the closing price of the Company’s stock on the grant date) shall be set forth in the award agreements attached hereto as Schedules A and B.  The stock option portion of the Initial Grant shall vest in five equal installments on each of the first five anniversaries of the grant date, and the restricted stock award portion of the Initial Grant shall vest in three equal installments on each of the first three anniversaries of the grant date.  The Board, in its sole discretion, may grant further incentive compensation awards to the Executive from time to time.  The Company represents and warrants to Executive that the Company has full power and authority, subject to Compensation Committee approval, and shares available under the Stock Plan to make the Initial Grant.

3.4                                  Benefits .  The Executive shall be entitled to participate in all bonus and benefit programs that the Company establishes and makes available to its employees, to the extent that the Executive is eligible under (and subject to the provisions of) the plan documents governing those programs.  The Executive shall be entitled to four (4) weeks paid vacation per year, accruing at a rate of 1.67 days per month during the Employment Period and to be taken at such times as may be reasonably determined by Executive consistent with his duties.

3.5                                  Reimbursement of Expenses .  The Company shall reimburse the Executive for all reasonable travel (which shall be deemed to include first class airfare or reimbursement or equivalent to a first class airfare ticket in the event Executive uses his

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personal time-share aircraft), entertainment and other expenses incurred or paid by the Executive in connection with, or related to, the performance of his duties, responsibilities or services under this Agreement or in connection with Executive’s commuting to and from his personal residence in the Philadelphia area and the Company’s offices, upon presentation by the Executive of documentation, expense statements, vouchers and/or such other supporting information as the Company may request.

3.6                                  Housing Expenses .  The Company understands that the Executive intends to maintain his primary residence outside the Massachusetts area.  The Company agrees to provide the Executive with a housing allowance for reasonable housing and living expenses of $5,600 per month, related to the rental or purchase of a home, within suitable distance to the Company’s headquarters, which payment shall be made on a fully tax grossed-up basis.  The Company also will reimburse the Executive for (i) reasonable travel, meals and lodging expenses incurred by him for up to two trips for the purpose of securing such house or apartment within a suitable distance to the Company’s headquarters and (ii) reasonable moving expenses in relocating his belongings from his residence in Florida to such house or apartment.

3.7                                  Executive’s Legal Fees.   The Company agrees to pay the Executive’s reasonable legal costs and expenses in connection with negotiating and drafting this Agreement up to a maximum of $15,000.

3.8                                  Automobile.   The Company agrees to provide the Executive with an automobile allowance or a leased automobile with a retail value of up to $75,000, which payments shall be made on a fully tax grossed-up basis.  In addition, the Company

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agrees to pay all insurance, maintenance, fuel and other customary costs associated with operating the automobile.

3.9                                  Withholding .  All salary, bonus and other compensation payable to the Executive shall be subject to applicable withholding taxes.

4.                                        Employment Termination .  This Agreement and the employment of the Executive under this Agreement shall terminate upon the occurrence of any of the following:

4.1                                  At the election of the Executive if the Company fails to name him Chief Executive Officer of the Company within six (6) months from the Commencement Date, on the date of such election.

4.2                                  On the expiration date of the Employment Period.

4.3                                  At the election of the Company, for Cause (as defined below), immediately upon written notice by the Company to the Executive, which notice shall identify the Cause upon which termination is based.  For the purposes of this Section 4.3, Cause for termination shall mean:  (a) the Executive’s willful and continued failure to substantially perform his reasonable assigned duties (other than any such failure resulting from incapacity due to physical or mental illness or any failure after the Executive gives notice of termination for Good Reason and Good Reason exists), which failure is not cured within 30 days after a written demand for substantial performance is received by the Executive from the Board of Directors of the Company which specifically identifies the manner in which the Board of Directors believes the Executive has not substantially performed the Executive’s duties; (b) the Executive’s willful engagement in illegal conduct or gross misconduct which is materially and demonstrably injurious to the

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Company; or (c) a material breach of Section 6 or 7 this Agreement by the Executive.  For purposes of this Section 4.3, no act or failure to act by the Executive shall be considered “willful” unless it is done, or omitted to be done, in bad faith and without reasonable belief that the Executive’s action or omission was in the best interests of the Company.

4.4                                  Upon the death or disability of the Executive.  As used in this Agreement, the term “disability” shall mean the Executive’s absence from the full-time performance of the Executive’s duties with the Company for one hundred eighty (180) consecutive calendar days as a result of incapacity due to mental or physical illness which is determined to be total and permanent by a physician selected by the Company or its insurers and acceptable to the Executive or the Executive’s legal representative.

4.5                                  At the election of the Executive for Good Reason as defined herein.  The Executive may terminate his employment for Good Reason at any time, following 30-days prior written notice of such termination to the Company.  Such notice shall provide factual details of the basis behind such termination and the Company shall have a thirty (30) day period thereafter to cure such matter.  As used herein, the term “Good Reason” shall mean:  (a) a material breach by the Company of the terms of this Agreement, including the failure to pay Base Salary or any Annual Bonus when due; or (b) any material adverse change by the Company in Executive’s titles, authorities, duties, responsibilities or lines of reporting inconsistent with the terms hereof or the assignment to Executive by the Company of titles, authorities, duties, responsibilities or lines of reporting inconsistent with the terms hereof, or (c) a relocation of the principal offices of

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the Company to an area more than forty (40) miles from the location of such offices as of the date hereof.

4.6                                  At the election of the Executive without Good Reason, upon not less than sixty (60) calendar days prior written notice of termination by the Executive to the Company; provided , however , that the Company may, in its sole discretion, determine that the termination of the Executive shall become effective immediately and in which case the termination shall still be considered at the election of the Executive without Good Reason.

4.7                                  At the election of the Company, without Cause, upon not less than sixty (60) days written notice to Executive.

4.8                                  At the election of the Company or the Executive in connection with a Change in Control of the Company as set forth in the Executive Retention Agreement between the Company and the Executive (the “ERA”), dated as of the date hereof.  For purposes of this Agreement, “Change in Control” shall have the meaning set forth in the ERA.

5.                                        Effect of Termination .

5.1                                  Termination For Failing To Name Executive CEO .  In the event the Company fails to name Executive to the position of Chief Executive Officer of the Company within six (6) months from the Commencement Date, and he elects to terminate his employment, provided the Executive executes and does not revoke a Separation Agreement and Release of Claims for the benefit of the Company substantially in the form set forth on Schedule C hereto (the “Separation Agreement”), the Company shall pay or cause to be paid to Executive, within thirty (30) days of the

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date of his termination: (1) a lump-sum payment of two million dollars ($2,000,000); and (2) the amount of any accrued but unpaid Base Salary, unused vacation and unreimbursed business, housing and automobile expenses and the Company thereafter shall have no further obligation to Executive under this Agreement, other than for payment of any other amounts or benefits accrued and vested under any applicable benefit plan or otherwise in accordance with applicable law.

5.2                                  Non-Renewal, Termination Without Good Reason By the Executive or Termination For Cause By the Company .  In the event the Executive’s employment is terminated by non-renewal pursuant to Section 4.2, for Cause by the Company pursuant to Section 4.3, or at the election of the Executive pursuant to Section 4.6, the Company shall pay to the Executive the compensation and benefits otherwise payable to him under Section 3 through the last calendar day of his actual employment by the Company.

5.3                                  Termination for Death or Disability .  In the event the Executive’s employment is terminated by death or because of disability pursuant to Section 4.4, the Company shall pay to the estate of the Executive or to the Executive, as the case may be, (A) within thirty (30) days of the date of the Executive’s death or determination of disability, the compensation which would otherwise be payable to the Executive up to the end of the month in which the termination of his employment because of death or disability occurs; and (B) an annual bonus in an amount equal to the total bonus he would be paid for such year, if any, multiplied by a fraction, the numerator of which is the number of days in the year that have elapsed since January 1 and the denominator of which is 365, payable when bonuses are paid for that year (a “Pro Rata Bonus”).  In

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addition, the Company shall permit Executive or Executive’s estate or representative to exercise the vested stock option portion of the Initial Grant for a period of no less than one year after any such termination of employment.

5.4                                  Termination By the Executive With Good Reason or By the Company Without “Cause” .  In the event the Executive’s employment is terminated by the Executive with Good Reason pursuant to Section 4.5 or by the Company without Cause pursuant to Section 4.7, the Company shall pay to the Executive the compensation and benefits otherwise payable to him under Section 3 through the last calendar day of his actual employment by the Company.  In addition, provided the Executive executes and does not revoke the Separation Agreement, the Company shall: (1) continue to pay the Executive the Base Salary for twenty-four (24) months in accordance with the Company’s regular payroll practices; (2) pay the Executive a Pro Rata Bonus; (3) pay the Executive, in bi-weekly installments, over a twenty-four month period, an amount equal in the aggregate to two (2) times the average Annual Bonus earned for the two years prior to the date of his termination (in the event Executive has not been employed for a sufficient period to earn two such bonuses, such calculation shall be made assuming Executive earned a bonus for any such year at a target level of performance (taking into account any minimum bonus amount)); (4) provide to the Executive for two (2) years following the date of his termination, payment of COBRA premiums for medical, dental, and vision benefits pursuant to plans maintained by the Company under which Executive and/or Executive’s family is eligible to receive benefits; provided, however, that, notwithstanding the foregoing, the benefits described in this subsection may be discontinued prior the end of the period, but only to the extent, that Executive receives

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substantially similar benefits from a subsequent employer; and (5) permit Executive to exercise the stock option portion of the Initial Grant for a period of no less than six months after the date of termination.

5.5                                  Termination Following a Change in Control .  In the event the Executive’s employment is terminated pursuant to Section 4.8 by the Company or by the Executive within 24 months following the Change in Control Date, as defined in the ERA, the Executive will be entitled to the benefits set forth in the ERA in accordance with the terms of the ERA. 

5.6                                  Six Month Delay .  If any payment, compensation or other benefit provided to the Executive in connection with his employment termination is determined, in whole or in part, to constitute “nonqualified deferred compensation” within the meaning of Section 409A and the Executive is a specified employee as defined in Section 409A(a)(2)(B)(i), no part of such payments shall be paid before the day that is six (6) months plus one (1) day after the date of his termination (the “New Payment Date”).  In the case of welfare benefit continuation, the Company shall use its best efforts to enable Executive to obtain such benefits at Executive’s expense prior to the New Payment Date.  The aggregate of any payments that otherwise would have been paid to the Executive (or on Executive’s behalf) during the period between the date of his termination and the New Payment Date shall be paid to the Executive in a lump sum on such New Payment Date.  Thereafter, any payments that remain outstanding as of the day immediately following the New Payment Date shall be paid without delay over the time period originally scheduled, in accordance with the terms of this Agreement.

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6.                                        Non-Competition and Non-Solicitation .

(a)                                   While the Executive is employed by the Company and for a period of twelve (12) months following the Executive’s termination or cessation of such employment for any reason, the Executive will not directly or indirectly:

(i)                                      Engage in any business or enterprise (whether as an owner, partner, officer, employee, director, investor, lender, consultant, independent contractor or otherwise, except as the holder of not more than 5% of the combined voting power of the outstanding stock of a publicly held company) that (A) is competitive with the Company’s business and (B) develops, designs, produces, markets, sells or renders any product or service competitive with any product or service developed, produced, marketed, sold or rendered by the Company while the Executive was employed by the Company;

(ii)                                   Either alone or in association with others, recruit or solicit any person who was employed by the Company at any time during the period of the Executive’s employment with the Company, except for an individual whose employment with the Company has been terminated for a period of six months or longer; and

(iii)                                Either alone or in association with others, solicit, divert or take away, or attempt to divert or take away, the business or patronage of any of the clients, customers or accounts, or prospective clients, customers or accounts, of the Company which were contacted, solicited or served by the Executive while he was employed by the Company.

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(b)                                  If any restriction set forth in this Section 6 is found by any court of competent jurisdiction to be unenforceable because it extends for too long a period of time or over too great a range of activities or in too broad a geographic area, it shall be interpreted to extend only over the maximum period of time, range of activities or geographic area as to which it may be enforceable.

(c)                                   The Executive acknowledges that the restrictions contained in this Agreement are necessary for the protection of the business and goodwill of the Company and are considered by the Executive to be reasonable for such purpose.  The Executive agrees that any material breach of this Agreement will cause the Company substantial and irrevocable damage and therefore, in the event of any such material breach, in addition to such other remedies which may be available, the Company shall have the right to seek specific performance and injunctive relief without posting a bond.

(d)                                  The geographic scope of this Section shall extend to anywhere the Company or any of its subsidiaries is doing business during the Term or has plans, during the Term, to do business.

(e)                                   The Executive agrees to provide a copy of this Agreement to all person and Entities with whom the Executive seeks to be hired or do business before accepting employment or engagement with any of them.

(f)                                     If the Executive violates the provisions of this Section, the Executive shall continue to be held by the restrictions set forth in this Section, until a period equal to the period of restriction has expired without any violation.

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7.                                        Proprietary Information and Developments .

7.1                                  Proprietary Information .

(a)                                   The Executive agrees that all information, whether or not in writing, of a private, secret or confidential nature concerning the Company’s business, business relationships or financial affairs (collectively, “Proprietary Information”) is and shall be the exclusive property of the Company.  By way of illustration, but not limitation, Proprietary Information may include discoveries, inventions, products, product improvements, product enhancements, processes, methods, techniques, formulas, compositions, compounds, negotiation strategies and positions, projects, developments, plans (including business and marketing plans), research data, clinical data, financial data (including sales, costs, profits and pricing methods), personnel data, computer programs (including software used pursuant to a license agreement), customer and supplier lists, and contacts at or knowledge of customers or prospective customers of the Company.  Except as required by applicable law, the Executive will not disclose any Proprietary Information to any person or entity other than employees of the Company or use the same for any purposes (other than in the performance of his duties as an employee of the Company) without prior written approval from the Board of Directors or a designee of the Board of Directors, either during or after his employment with the Company, unless and until such Proprietary Information has become public knowledge without fault by the Executive.

(b)                                  The Executive agrees that all files, documents, letters, memoranda, reports, records, data, sketches, drawings, methods, laboratory notebooks, program listings, computer equipment or devices, computer programs or other written,

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photographic, or other tangible material containing Proprietary Information, whether created by the Executive or others, which shall come into his custody or possession, shall be and are the exclusive property of the Company and are to be used by the Executive only in the performance of his duties for the Company.  All such materials or copies thereof and all tangible property of the Company in the custody or possession of the Executive shall be delivered to the Company upon the earlier of (i) a request by the Company or (ii) termination of his employment.  After such delivery, the Executive shall not retain any such materials or copies thereof or any such tangible property.

(c)                                   The Executive agrees that his obligation not to disclose or to use information and materials of the types set forth in subsections (a) and (b) above, and his obligation to return materials and tangible property set forth in subsection (b) above, also extends to such types of information, materials and tangible property of customers of the Company or suppliers to the Company or other third parties who may have disclosed or entrusted the same to the Company or to the Executive.

7.2                                  Developments.

(a)                                   The Executive will make full and prompt disclosure to the Company of all inventions, creations, improvements, discoveries, trade secrets, secret processes, technology, know-how, copyrightable materials, methods, developments, software, and works of authorship or other creative works, whether patentable or not, which are created, made, conceived or reduced to practice by him or under his direction or jointly with others during his employment by the Company, whether or not during normal working hours or on the premises of the Company (all of which are collectively referred to in this Agreement as “Developments”).

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