EX-10.3



 EXHIBIT 10.3 

AMBIT BIOSCIENCES CORPORATION 

RESTATED EMPLOYMENT AGREEMENT 

This RESTATED EMPLOYMENT AGREEMENT (this
“Agreement”) is effective as of January 8, 2014 (the “Effective Date”) by and among AMBIT BIOSCIENCES CORPORATION (the
“Company”) and Athena Countouriotis (the “Executive”). The Company and Executive are hereinafter collectively referred to as the “Parties”, and individually referred to as a
“Party”. 
 RECITALS 

A. The Parties previously entered into that certain offer letter, dated January 20, 2012 (as amended, the “Prior
Agreement”), and desire to restate and supersede such Prior Agreement with the terms and conditions set forth in this Agreement. 
 B.
The Company desires assurance of the association and services of Executive in order to retain Executive’s experience, skills, abilities, background and knowledge, and is willing to continue the engagement of Executive’s services on the
terms and conditions set forth in this Agreement. 
 C. Executive desires to continue to be in the employ of the Company, and is willing to accept
such continued employment on the terms and conditions set forth in this Agreement. 
 AGREEMENT 

In consideration of the foregoing Recitals and the mutual promises and covenants herein contained, and for other good and valuable
consideration, the Parties, intending to be legally bound, agree as follows: 
  

	 	1.	EMPLOYMENT. 

 1.1 Title. Executive’s position shall be Chief
Medical Officer of the Company, subject to the terms and conditions set forth in this Agreement. 
 1.2 Term. The term of this
Agreement shall begin on the Effective Date and shall continue until it is terminated pursuant to Section 4 herein (the “Term”). 

1.3 Duties. Executive shall do and perform all services, acts or things necessary or advisable to manage and conduct the business of
the Company and that are normally associated with the position of Chief Medical Officer. Executive shall report to the Chief Executive Officer of the Company. 

1.4 Policies and Practices. The employment relationship between the Parties shall be governed by this Agreement and by the policies and
practices established by the Company and/or the Company’s Board of Directors (the “Board”), or any designated committee thereof. In the event that the terms of this Agreement differ from or are in conflict with the
Company’s policies or practices or the Company’s Employee Handbook, this Agreement shall control. 







 1.5 Location. Unless the Parties otherwise agree in writing, during the Term
Executive shall perform the services Executive is required to perform pursuant to this Agreement at the Company’s offices in San Diego, California, provided, however, that the Company may from time to time require Executive to
travel temporarily to other locations in connection with the Company’s business. 
  

	 	2.	LOYALTY; NONCOMPETITION; NONSOLICITATION. 


2.1 Loyalty. During Executive’s employment with the Company, Executive shall devote Executive’s full business energies,
interest, abilities and productive time to the proper and efficient performance of Executive’s duties under this Agreement; provided, however, that Executive shall be entitled to serve on the board of directors of such other companies as may be
approved in advance by the Board, in each case so long as Executive remains in compliance with Section 2.2 and such service does not interfere with Executive’s duties under this Agreement. 

2.2 Agreement not to Participate in Company’s Competitors. During Executive’s employment with the Company, Executive agrees
not to acquire, assume or participate in, directly or indirectly, any position, investment or interest known by Executive to be adverse or antagonistic to the Company, its business, or prospects, financial or otherwise, or in any company, person, or
entity that is, directly or indirectly, in competition with the business of the Company or any of its Affiliates (as defined below). Ownership by Executive, in professionally managed funds over which the Executive does not have control or discretion
in investment decisions, or as a passive investment, of less than two percent (2%) of the outstanding shares of capital stock of any corporation with one or more classes of its capital stock listed on a national securities exchange or publicly
traded on a national securities exchange or in the over-the-counter market shall not constitute a breach of this Section. For purposes of this Agreement, “Affiliate,” means, with respect to any specific entity, any other
entity that, directly or indirectly, through one or more intermediaries, controls, is controlled by or is under common control with such specified entity. 

2.3 Covenant not to Compete. During Executive’s employment with the Company, the Executive shall not engage in competition with
the Company and/or any of its Affiliates, either directly or indirectly, in any manner or capacity, as adviser, principal, agent, affiliate, promoter, partner, officer, director, employee, stockholder, owner, co-owner, consultant, or member of any
association or otherwise, in any phase of the business of developing, manufacturing and marketing of products or services that are in the same field of use or which otherwise compete with the products or services of the Company, except with the
prior written consent of the Board. 
  

	 	3.	COMPENSATION OF THE EXECUTIVE. 


3.1 Base Salary. Effective as of January 1, 2014, the Company shall pay Executive a base salary at the annualized rate of $376,000
(the “Base Salary”), less payroll deductions and all required withholdings, payable in regular periodic installments in accordance with the Company’s normal payroll practices. The Base Salary shall be prorated for any
partial year of employment on the basis of a 365-day fiscal year. 

  
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 3.2 Discretionary Bonus. At the sole discretion of the Board, following each calendar year
of employment Executive shall be eligible to receive a discretionary cash bonus with a target amount of up to thirty percent (30%) of Executive’s then-current base salary (the “Bonus”), based on Executive’s
achievement relative to certain performance goals (“Performance Goals”) to be established by the Board. The determination of whether Executive has met the Performance Goals for any given year, and if so, the amount of any
Bonus that will be paid for such year (if any), shall be determined by the Board in its sole and absolute discretion. In order to be eligible to earn or receive any Bonus, except as provided in Sections 4.5.3 and 4.5.4, Executive must remain
employed by the Company through and including the end of the year with respect to which such Bonus is earned. Any earned Bonus will be paid no later than March 15th of the calendar year
immediately following the year with respect to which the Bonus was earned. 
 3.3 Expense Reimbursements. The Company will reimburse
Executive for all reasonable business expenses Executive incurs in conducting her duties hereunder, pursuant to the Company’s usual expense reimbursement policies; provided that Executive supplies the appropriate substantiation for such
expenses no later than the end of the calendar month following the month in which such expenses were incurred by Executive. For the avoidance of doubt, to the extent that any expense reimbursements payable to Executive are taxable income and subject
to the provisions of Section 409A of the Internal Revenue Code of 1986, as amended (the “Code”) and the regulations and other guidance thereunder and any state law of similar effect (collectively “Section
409A”): (i) to be eligible to obtain reimbursement for such expenses Executive must supply the appropriate documentation substantiating such expenses no later than the end of the calendar month following the month in which such
expenses were incurred by Executive, (ii) any such reimbursements will be paid by the Company as soon as administratively practicable after submission of such documentation, but in no event later than December 31 of the year following the
year in which the expense was incurred, (iii) the amount of expenses reimbursed in one year will not affect the amount eligible for reimbursement in any subsequent year, and (iv) the right to expense reimbursement under this Agreement will
not be subject to liquidation or exchange for another benefit. 
 3.4 Changes to Compensation. Executive’s compensation will be
reviewed annually and may be increased from time to time in the Company’s sole discretion. 
 3.5 Employment Taxes. All
of Executive’s compensation shall be subject to customary withholding taxes and any other employment taxes as are commonly required to be collected or withheld by the Company. 

3.6 Benefits. Executive shall, in accordance with Company policy and the terms of the applicable plan documents, be eligible to
participate in benefits under any benefit plan or arrangement that may be in effect from time to time and made available to the Company’s senior management employees. 

3.7 Holidays and Vacation. Executive shall be eligible to accrue four (4) weeks of paid vacation per year and will receive paid
Company holidays in accordance with Company policy. 

  
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	 	4.	TERMINATION. 

 4.1 Termination by the Company.
Executive’s employment with the Company is at will and may be terminated by the Company at any time and for any reason, or for no reason, including, but not limited to, under the following conditions: 

4.1.1 Termination by the Company for Cause. The Company may terminate Executive’s employment under this Agreement for
“Cause” (as defined below) by delivery of written notice to Executive. Any notice of termination given pursuant to this section shall effect termination as of the date of the notice, or as of such other date specified in the notice. 

4.1.2 Termination by the Company without Cause. The Company may terminate Executive’s employment under this Agreement
without Cause at any time and for any reason, or for no reason. Such termination shall be effective on the date Executive is so informed by the Company. 

4.2 Termination By Executive. Executive may terminate her employment with the Company at any time and for any reason, or for no reason,
upon thirty (30) days written notice to the Company. 
 4.3 Termination for Death or Complete Disability.
Executive’s employment with the Company shall automatically terminate effective upon the date of Executive’s death or Complete Disability (as defined below). 

4.4 Termination by Mutual Agreement of the Parties. Executive’s employment with the Company may be terminated at any time
upon a mutual agreement in writing of the Parties. Any such termination of employment shall have the consequences specified in such agreement. 

4.5 Compensation Upon Termination. 

4.5.1 Death or Complete Disability. If Executive’s employment is terminated by death or due to Complete Disability, the
Company shall pay to Executive, or to Executive’s heirs, Executive’s base salary and accrued and unused vacation benefits earned through the date of termination at the rate in effect at the time of termination, less standard deductions and
withholdings. The Company shall thereafter have no further obligations to Executive and/or Executive’s heirs under this Agreement, except as otherwise provided by law (and except as provided otherwise in Executive’s stock option agreements
with the Company). 
 4.5.2 Termination For Cause If the Company terminates Executive’s employment for Cause, then the Company
shall pay Executive’s base salary and accrued and unused vacation benefits earned through the date of termination, at the rate in effect at the time of termination, less standard deductions and withholdings. The Company shall thereafter have no
further obligations to Executive under this Agreement, except as otherwise provided by law (and except as provided otherwise in Executive’s stock option agreements with the Company). 

  
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 4.5.3 Termination Without Cause Not In Connection with a Covered Transaction. If the
Company terminates Executive’s employment without Cause and not due to the Executive’s Complete Disability at any time other than within the period commencing three (3) months immediately prior to and ending twelve (12) months
immediately following the effective date of a Covered Transaction, the Company shall pay Executive’s base salary and accrued and unused vacation benefits earned through the date of termination, at the rate in effect at the time of termination,
less standard deductions and withholdings. In addition, if Executive furnishes to the Company an executed waiver and release of claims in the form attached hereto as Exhibit A (the “Release”) within the time
period specified therein, but in no event later than forty-five (45) days following Executive’s termination, and if Executive allows such Release to become effective in accordance with its terms, then Executive shall be entitled to receive
the following severance benefits: 
 4.5.3.1 cash payments in the form of continuation of Executive’s base salary at the rate
in effect at the time of termination for a period of twelve (12) months following the termination date, and 
 4.5.3.2 provided
that Executive is eligible for and timely elects continued group health plan coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985 (“COBRA”) following the Executive’s termination date, the Company
shall pay directly to the insurance provider the premium for COBRA continuation coverage for the Executive and the Executive’s family for a period that will expire upon the earliest of (i) twelve (12) months following the termination
date (the “COBRA Payment Period”), (ii) the effective date that Executive becomes eligible for new healthcare coverage eligibility available through new employment, or (iii) the date Executive is no longer eligible
for COBRA coverage, whichever comes first. 
 4.5.3.3 the vesting of any unvested portion of options to purchase shares of the
Company’s stock then outstanding and held by Executive (“Options”) shall accelerate such that the number shares subject to the Options that would have been vested had Executive continued to provide services to the
Company until the date that is the one-year anniversary of the date of Executive’s termination date shall be vested on the effective date of the Release. 

4.5.4 Termination Without Cause or Resignation for Good Reason In Connection with a Covered Transaction. If the Company terminates
Executive’s employment without Cause and not due to the Executive’s Complete Disability or if the Executive terminates her employment for Good Reason, in each case within the period commencing three (3) months immediately prior to and
ending twelve (12) months immediately following the effective date of a Covered Transaction, the Company shall pay Executive’s base salary and accrued and unused vacation benefits earned through the date of termination, at the rate in
effect at the time of termination, less standard deductions and withholdings. In addition, if Executive furnishes to the Company an executed Release within the time period specified therein, but in no event later than forty-five (45) days
following Executive’s termination, and if Executive allows such Release to become effective in accordance with its terms, then (i) Executive shall be entitled to receive the following severance benefits: 

4.5.4.1 cash payments in the form of continuation of Executive’s base salary, at the rate in effect at the time of termination
but without giving effect to any reduction in base salary that would give rise to Executive’s right to resign for Good Reason, for a period of twelve (12) months following the termination date, 

  
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 4.5.4.2 a lump sum payment equal to the target Bonus in effect for the year in which the
Executive’s termination occurs, payable in a single lump sum during the first payroll period following the effective date of the Release, 

4.5.4.3 provided that Executive is eligible for and timely elects continued group health plan coverage under COBRA following the
Executive’s termination date, the Company shall pay directly to the insurance provider the premium for COBRA continuation coverage for the Executive and the Executive’s family for a period that will expire upon the earlier of
(i) twelve (12) months following the termination date (the “COBRA Severance Period”), (ii) the effective date that Executive becomes eligible for new healthcare coverage eligibility available through new
employment, or (iii) the date Executive is no longer eligible for COBRA coverage, whichever comes first, and 
 4.5.4.4 the
vesting of any unvested portion of Options shall accelerate such that Executive shall become vested in one hundred percent (100%) of the shares subject to such Options on the effective date of the Release. In order to give effect to the intent
of the foregoing provision, in no event will Executive’s outstanding unvested stock options terminate and be forfeited any earlier than three (3) months following the date of Executive’s termination without Cause or resignation for
Good Reason that precedes a Covered Transaction. 
 4.5.5 General Severance Benefit Terms. 

4.5.5.1 The provisions in this Section 4.5.5.1 shall control and supersede anything to the contrary set forth in this Agreement.
For all purposes of this Agreement, references to COBRA premiums shall not include any amounts payable by Executive under a Section 125 health care reimbursement plan under the Code. If at any time the Company determines, in its sole
discretion, that it cannot pay the COBRA premiums without potentially incurring financial costs or penalties under applicable law (including, without limitation, Section 2716 of the Public Health Service Act), then regardless of whether
Executive elects continued health coverage under COBRA, and in lieu of providing the COBRA premiums, the Company will instead pay Executive on the last day of each remaining month of the COBRA Payment Period or COBRA Severance Period, as applicable,
a fully taxable cash payment equal to the COBRA premiums for that month, subject to applicable tax withholdings, which payments shall continue until the earlier of expiration of the COBRA Payment Period or COBRA Severance Period, as applicable, or
the date when Executive becomes eligible for health insurance coverage in connection with new employment. If Executive becomes eligible for coverage under another employer’s group health plan, Executive must immediately notify the Company of
such event, and all COBRA severance benefit payments and obligations under this Agreement shall cease effective as of such date of the Executive’s eligibility. 

4.5.5.2 All severance payments made under this Agreement will be subject to standard payroll deductions and withholdings and will be
made on the Company’s 

  
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regular payroll cycle, provided, however, that any severance payments otherwise scheduled to be made prior to the effective date of the Release shall instead accrue and be paid in the first
payroll period that follows such effective date. Following provision of any severance benefits to which the Executive may be entitled under Section 4.5.3 or 4.5.4, the Company shall thereafter have no further obligations to Executive under this
Agreement, except as otherwise provided by law (and except as provided otherwise in Executive’s stock option agreements with the Company). 

4.5.6 No Duplication of Severance Benefits. For the avoidance of doubt, in no event will Executive be entitled to severance benefits
under both Section 4.5.3 and Section 4.5.4. 
 4.6 Additional Definitions. For purposes of this Agreement, the following
terms shall have the following meanings: 
 4.6.1 “Complete Disability” shall mean the inability of
Executive to perform Executive’s duties under this Agreement, whether with or without reasonable accommodation, because Executive has become permanently disabled within the meaning of any policy of disability income insurance covering employees
of the Company then in force. In the event the Company has no policy of disability income insurance covering employees of the Company in force when Executive becomes disabled, the term “Complete Disability” shall mean the
inability of Executive to perform Executive’s duties under this Agreement, whether with or without reasonable accommodation, by reason of any incapacity, physical or mental, which the Board, based upon medical advice or an opinion provided by a
licensed physician acceptable to the Board, determines to have incapacitated Executive from satisfactorily performing all of Executive’s usual services for the Company, with or without reasonable accommodation, for a period of at least one
hundred twenty (120) days during any twelve (12) month period (whether or not consecutive). Based upon such medical advice or opinion, the determination of the Board shall be final and binding and the date such determination is made shall
be the date of such Complete Disability for purposes of this Agreement. 
 4.6.2 “Cause” shall mean the
occurrence of any of the following: (i) Executive’s conviction of any felony or any crime involving fraud or dishonesty that has a material adverse effect on the Company; (ii) Executive’s active participation (whether by
affirmative act or material omission) in a fraud, act of dishonesty or other act of misconduct against the Company and/or its affiliates; (iii) conduct by Executive which, based upon a good faith and reasonable factual investigation by the
Board, demonstrates Executive’s gross unfitness to serve; (iv) Executive’s material violation of any statutory or fiduciary duty, or duty of loyalty, owed to the Company; (v) Executive’s breach of any material term of any
material contract between such Executive and the Company and the failure to cure such breach within 30 days of written notice; and (vi) Executive’s repeated violation of any material Company policy. An occurrence of “cause” as
set forth in the preceding sentence shall be based upon a good faith determination by the Board. Executive’s Complete Disability shall not constitute Cause as set forth herein. The determination that a termination is for Cause shall be by the
Board in its sole and exclusive judgment and discretion. 
 4.6.3 “Covered Transaction” means the
occurrence, in a single transaction or in a series of related transactions of the first to occur of the following events that 

  
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also constitutes a change in the ownership or effective control of the Company, or a change in the ownership of a substantial portion of the Company’s assets, as described in Treasury
Regulations Section 1.409A-3(i)(5): (1) a merger or consolidation of the Company in which the Company’s stockholders immediately prior to such transaction do not immediately following such transaction own at least a majority of the
surviving corporation’s voting shares; (2) a sale of all or substantially all of the Company’s assets or (3) a sale or other transfer of shares of the Company’s capital stock as a result of which the Company’s
stockholders immediately prior to such transaction do not immediately following such transaction own at least a majority of the surviving corporation’s voting shares, other than a transaction involving the issuance of shares by the Company
primarily for the purpose of raising capital for the Company. 
 4.6.4 “Good Reason” shall mean: (i) a
material reduction of Executive’s base compensation, unless such reduction is consistent with and generally applicable to all the Company’s executive officers and is agreed to in writing by Executive; (ii) a material reduction of the
Executive’s authority, responsibilities or duties with the Company; or (iii) the Executive being required to relocate the Executive’s principal place of employment with the Company as of the Effective Date to a principal place of
employment more than fifty (50) miles from San Diego, California, in each case without the Executive’s prior consent; provided, however, that Executive’s termination shall only be for Good Reason if: (i) Executive gives
the Board written notice of the intent to terminate for Good Reason within sixty (60) days following the first occurrence of the condition(s) that the Executive believes constitutes Good Reason, which notice shall describe such condition(s),
and (ii) the Board has a period of not less than thirty (30) days to cure the Good Reason resignation triggering condition following its receipt of such notice (the “Cure Period”), (iii) the Good Reason
resignation triggering condition is not cured prior to expiration of the Cure Period, and (iv) Executive resigns within the thirty (30) day period following the expiration of the Cure Period. 

4.7 Survival of Certain Sections. Sections 2, 3.4, 4 through 13, 16, and 18 of this Agreement will survive the termination of this
Agreement. 
 4.8 Parachute Payment. If any payment or benefit the Executive would receive pursuant to this Agreement
(“Payment”) would (i) constitute a “Parachute Payment” within the meaning of Section 280G of the Code, and (ii) but for this sentence, be subject to the excise tax imposed by
Section 4999 of the Code (the “Excise Tax”), then such Payment shall be equal to the Reduced Amount. The “Reduced Amount” shall be either (x) the largest portion of the Payment that would
result in no portion of the Payment being subject to the Excise Tax or (y) the largest portion, up to and including the total of the Payment, whichever amount, after taking into account all applicable federal, state and local employment taxes,
income taxes, and the Excise Tax (all computed at the highest applicable marginal rate), results in the Executive’s receipt, on an after-tax basis, of the greatest economic benefit notwithstanding that all or some portion of the Payment may be
subject to the Excise Tax. If a reduction in payments or benefits constituting Parachute Payments is necessary so that the Payment equals the Reduced Amount, reduction shall occur in the manner that results in the greatest economic benefit for the
Executive. If more than one method of reduction will result in the same economic benefit, the items so reduced will be reduced pro rata. 

  
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 In the event it is subsequently determined by the Internal Revenue Service that some portion of
the Reduced Amount (as determined pursuant to clause (x) in the preceding paragraph) is subject to the Excise Tax, Executive agrees to promptly return to the Company a sufficient amount of the Payment so that no portion of the Reduced Amount is
subject to the Excise Tax. For the avoidance of doubt, if the Reduced Amount is determined in accordance with clause (y) in the preceding paragraph, Executive will have no obligation to return any portion of the Payment pursuant to the
preceding sentence. 
 Unless Executive and the Company agree on an alternative accounting or law firm, the accounting firm then engaged by
the Company for general tax compliance purposes shall perform the foregoing calculations. If the accounting firm so engaged by the Company is serving as accountant or auditor for the individual, entity or group effecting the Change in Control, the
Company shall appoint a nationally recognized accounting, law or consulting firm to make the determinations required hereunder. The Company shall bear all expenses with respect to the determinations by such accounting, law or consulting firm
required to be made hereunder. 
 The Company shall use commercially reasonable efforts such that the accounting, law or consulting firm
engaged to make the determinations hereunder shall provide its calculations, together with detailed supporting documentation, to Executive and the Company within fifteen (15) calendar days after the date on which Executive’s right to a
Payment is triggered (if requested at that time by the Executive or the Company) or such other time as requested by the Executive or the Company. 

In the event the payment of any amounts pursuant to this letter agreement would result in Executive being subject to an Excise Tax (without
giving effect to any reduction in such payments to the Reduced Amount), at Executive’s request in Executive’s sole discretion, the Company will use its commercially reasonable best efforts to obtain a vote of the stockholders of the
Company approving such payments in the manner set forth in Section 280G(b)(5)(B) of the Code and the Treasury Regulations issued thereunder such that the payments would not be subject to the Excise Tax if the required stockholder approval is
obtained. In the event Executive so requests that such a vote be taken, Executive agrees to execute a waiver and enter into such additional agreements as may be reasonably requested by the Company in relation thereto, including, without limitation,
agreeing that the portion of such payments that would otherwise, if made, result in Executive becoming liable for the Excise Tax will not be made if the required stockholder approval is not obtained. 

4.9 Application of Internal Revenue Code Section 409A. Notwithstanding anything to the contrary set forth herein, any payments and
benefits provided under this Agreement (the “Severance Benefits”) that constitute “deferred compensation” within the meaning of Section 409A shall not commence in connection with Executive’s termination of
employment unless and until Executive has also incurred a “separation from service” (as such term is defined in Treasury Regulation Section 1.409A-1(h) (“Separation From Service”), unless the Company reasonably
determines that such amounts may be provided to Executive without causing Executive to incur the additional 20% tax under Section 409A. 

It is intended that each installment of the Severance Benefits payments provided for in this Agreement is a separate “payment” for
purposes of Treasury Regulation Section 1.409A-2(b)(2)(i). 

  
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 For the avoidance of doubt, it is intended that payments of the Severance Benefits set forth in this Agreement
satisfy, to the greatest extent possible, the exemptions from the application of Section 409A provided under Treasury Regulation Sections 1.409A-1(b)(4), 1.409A-1(b)(5) and 1.409A-1(b)(9). However, if the Company (or, if applicable, the
successor entity thereto) determines that the Severance Benefits constitute “deferred compensation” under Section 409A and Executive is, on the termination of service, a “specified employee” of the Company or any successor
entity thereto, as such term is defined in Section 409A(a)(2)(B)(i) of the Code, then, solely to the extent necessary to avoid the incurrence of the adverse personal tax consequences under Section 409A, the timing of the Severance Benefit
payments shall be delayed until the earlier to occur of: (i) the date that is six months and one day after Executive’s Separation From Service, or (ii) the date of Executive’s death (such applicable date, the
“Specified Employee Initial Payment Date”), the Company (or the successor entity thereto, as applicable) shall (A) pay to Executive a lump sum amount equal to the sum of the Severance Benefit payments that Executive
would otherwise have received through the Specified Employee Initial Payment Date if the commencement of the payment of the Severance Benefits had not been so delayed pursuant to this Section and (B) commence paying the balance of the Severance
Benefits in accordance with the applicable payment schedules set forth in this Agreement. 
 Notwithstanding anything to the contrary set
forth herein, Executive shall receive the Severance Benefits described above, if and only if Executive duly executes and returns to the Company within the applicable time period set forth therein, but in no event more than forty-five days following
Separation From Service, the Release and permits the Release to become effective in accordance with its terms. Notwithstanding any other payment schedule set forth in this Agreement, none of the Severance Benefits will be paid or otherwise delivered
prior to the effective date of the Release. Except to the extent that payments may be delayed until the Specified Employee Initial Payment Date pursuant to the preceding paragraph, on the first regular payroll pay day following the effective date of
the Release, the Company will pay Executive the Severance Benefits Executive would otherwise have received under the Agreement on or prior to such date but for the delay in payment related to the effectiveness of the Release, with the balance of the
Severance Benefits being paid as originally scheduled. All amounts payable under the Agreement will be subject to standard payroll taxes and deductions. 

The severance benefits are intended to qualify for an exemption from application of Section 409A or comply with its requirements to the
extent necessary to avoid adverse personal tax consequences under Section 409A, and any ambiguities herein shall be interpreted accordingly. 
  

	 	5.	CONFIDENTIAL AND PROPRIETARY INFORMATION. 


As a condition of continued employment, Executive agrees to continue to abide by the Company’s standard form of Proprietary Information
and Inventions Agreement which was signed in connection with the Prior Agreement (“PIIA”). 
  

	 	6.	ASSIGNMENT AND BINDING EFFECT. 


This Agreement shall be binding upon and inure to the benefit of Executive and Executive’s heirs, executors, personal representatives,
assigns, administrators and legal 

  
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representatives. Because of the unique and personal nature of Executive’s duties under this Agreement, neither this Agreement nor any rights or obligations under this Agreement shall be
assignable by Executive. This Agreement shall be binding upon and inure to the benefit of the Company and its successors, assigns and legal representatives. Any such successor of the Company will be deemed substituted for the Company under the terms
of this Agreement for all purposes. For this purpose, “successor” means any person, firm, corporation or other business entity which at any tie, whether by purchase, merger or otherwise, directly or indirectly acquires all or substantially
all of the assets or business of the Company. 
  

	 	7.	Notices. 

 All notices or demands of any kind required or permitted to be given by the
Company or Executive under this Agreement shall be given in writing and shall be personally delivered (and receipted for) or faxed during normal business hours or mailed by certified mail, return receipt requested, postage prepaid, addressed as
follows: 
 If to the Company: 

Ambit Biosciences Corporation 

11080 Roselle St. 
 San Diego, CA
92121 
 Attention: Chairman of the Board 

If to Executive: 
 Athena
Countouriotis 
 2295 Galena Ave. 

Carlsbad, CA 92009 
 Any such written notice
shall be deemed given on the earlier of the date on which such notice is personally delivered or three (3) days after its deposit in the United States mail as specified above. Either Party may change its address for notices by giving notice to
the other Party in the manner specified in this Section. 
  

	 	8.	CHOICE OF LAW. 

 This Agreement shall be
construed and interpreted in accordance with the internal laws of the State of California without regard to its conflict of laws principles. 
  

	 	9.	INTEGRATION. 

 This Agreement, including Exhibit A and the PIIA, contains
the complete, final and exclusive agreement of the Parties relating to the terms and conditions of Executive’s employment and the termination of Executive’s employment, and supersedes any and all prior and/or contemporaneous oral and
written employment agreements or arrangements between the Parties regarding Executive’s service with the Company, including, without limitation, the Prior Agreement. 

  
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	 	10.	AMENDMENT. 

 This Agreement cannot be amended or modified except by a
written agreement signed by Executive and the Company. 
  

	 	11.	WAIVER. 

 No term, covenant or condition of this Agreement or any breach
thereof shall be deemed waived, except with the written consent of the Party against whom the wavier is claimed, and any waiver or any such term, covenant, condition or breach shall not be deemed to be a waiver of any preceding or succeeding breach
of the same or any other term, covenant, condition or breach. 
  

	 	12.	SEVERABILITY. 

 The finding by a court of competent jurisdiction of the
unenforceability, invalidity or illegality of any provision of this Agreement shall not render any other provision of this Agreement unenforceable, invalid or illegal. Such court shall have the authority to modify or replace the invalid or
unenforceable term or provision with a valid and enforceable term or provision, which most accurately represents the Parties’ intention with respect to the invalid or unenforceable term, or provision. 

 

	 	13.	INTERPRETATION; CONSTRUCTION. 

 The headings set forth in
this Agreement are for convenience of reference only and shall not be used in interpreting this Agreement. This Agreement has been drafted by legal counsel representing the Company, but the Executive has been encouraged to consult with, and has
consulted with, Executive’s own independent counsel and tax advisors with respect to the terms of this Agreement. The Parties acknowledge that each Party and its counsel has reviewed and revised, or had an opportunity to review and revise, this
Agreement, and any rule of construction to the effect that any ambiguities are to be resolved against the drafting party shall not be employed in the interpretation of this Agreement. 

 

	 	14.	REPRESENTATIONS AND WARRANTIES. 

 Executive
represents and warrants that Executive is not restricted or prohibited, contractually or otherwise, from entering into and performing each of the terms and covenants contained in this Agreement, and that Executive’s execution and performance of
this Agreement will not violate or breach any other agreements between the Executive and any other person or entity. 
  

	 	15.	COUNTERPARTS. 

 This Agreement may be executed in two counterparts, each
of which shall be deemed an original, all of which together shall contribute one and the same instrument. 

  
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	 	16.	ARBITRATION. 

 To ensure the rapid and economical resolution of disputes
that may arise in connection with the Executive’s employment with the Company, Executive and the Company agree that any and all disputes, claims, or causes of action, in law or equity, arising from or relating to Executive’s employment, or
the termination of that employment, will be resolved, to the fullest extent permitted by law, by final, binding and confidential arbitration pursuant to both the substantive and procedural provisions of the Federal Arbitration Act in San Diego,
California conducted by the Judicial Arbitration and Mediation Services/Endispute, Inc. (“JAMS”), or its successors, under the then current rules of JAMS for employment disputes; provided that the arbitrator shall:
(a) have the authority to compel adequate discovery for the resolution of the dispute and to award such relief as would otherwise be permitted by law; and (b) issue a written arbitration decision including the arbitrator’s essential
findings and conclusions and a statement of the award. Accordingly, Executive and the Company hereby waive any right to a jury trial. Both Executive and the Company shall be entitled to all rights and remedies that either Executive or the Company
would be entitled to pursue in a court of law. The Company shall pay any JAMS filing fee and shall pay the arbitrator’s fee. Nothing in this Agreement is intended to prevent either Executive or the Company from obtaining injunctive relief in
court to prevent irreparable harm pending the conclusion of any such arbitration. Notwithstanding the foregoing, Executive and the Company each have the right to resolve any issue or dispute involving confidential, proprietary or trade secret
information, or intellectual property rights, by Court action instead of arbitration. 
  

	 	17.	TRADE SECRETS OF OTHERS. 

 It
is the understanding of both the Company and Executive that Executive shall not divulge to the Company and/or its subsidiaries any confidential information or trade secrets belonging to others, including Executive’s former employers, nor shall
the Company and/or its Affiliates seek to elicit from Executive any such information. Consistent with the foregoing, Executive shall not provide to the Company and/or its Affiliates, and the Company and/or its Affiliates shall not request, any
documents or copies of documents containing such information. 
  

	 	18.	ADVERTISING WAIVER. 

 Executive agrees to permit the
Company, and persons or other organizations authorized by the Company, to use, publish and distribute advertising or sales promotional literature concerning the products and/or services of the Company, or the machinery and equipment used in the
provision thereof, in which Executive’s name and/or pictures of Executive taken in the course of Executive’s provision of services to the Company appear. Executive hereby waives and releases any claim or right Executive may otherwise have
arising out of such use, publication or distribution. 
 [REMAINDER OF THIS PAGE
INTENTIONALLY LEFT BLANK] 

  
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 IN WITNESS WHEREOF, the
Parties have executed this Agreement effective as of the date first above written. 
  

			
	AMBIT BIOSCIENCES CORPORATION
		
	By:	 	 /s/ Michael Martino

	Its:	 	 CEO


  

	
	EXECUTIVE:
	
	 /s/ Athena Countouriotis

	ATHENA COUNTOURIOTIS


  
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 EXHIBIT A 

RELEASE AND WAIVER OF CLAIMS 

TO BE SIGNED ON OR FOLLOWING THE SEPARATION DATE ONLY 

In consideration of the payments and other benefits set forth in the Restated Employment Agreement of January 8, 2014, to which this form
is attached (the “Employment Agreement”), I, Athena Countouriotis, hereby furnish Ambit Biosciences Corporation (the “Company”), with the following release and waiver (“Release and
Waiver”). 
 In exchange for the consideration provided to me by the Employment Agreement that I am not otherwise entitled to
receive, I hereby generally and completely release the Company and its current and former directors, officers, employees, stockholders, partners, agents, attorneys, predecessors, successors, parent and subsidiary entities, insurers, affiliates, and
assigns (collectively, the “Released Parties”) from any and all claims, liabilities and obligations, both known and unknown, that arise out of or are in any way related to events, acts, conduct, or omissions occurring prior
to or on the date that I sign this Agreement (collectively, the “Released Claims”). The Released Claims include, but are not limited to: (a) all claims arising out of or in any way related to my employment with the
Company, or the termination of that employment; (b) all claims related to my compensation or benefits from the Company including salary, bonuses, commissions, vacation pay, expense reimbursements, severance pay, fringe benefits, stock, stock
options, or any other ownership interests in the Company; (c) all claims for breach of contract, wrongful termination, and breach of the implied covenant of good faith and fair dealing; (d) all tort claims, including claims for fraud,
defamation, emotional distress, and discharge in violation of public policy; and (e) all federal, state, and local statutory claims, including claims for discrimination, harassment, retaliation, misclassification, attorneys’ fees, or other
claims arising under the federal Civil Rights Act of 1964 (as amended), the federal Americans with Disabilities Act of 1990, the federal Age Discrimination in Employment Act of 1967 (as amended) (the “ADEA”), the California
Labor Code, and the California Fair Employment and Housing Act (as amended). Notwithstanding the foregoing, the following are not included in the Released Claims (the “Excluded Claims”): (a) any rights or claims for
indemnification I may have pursuant to any written indemnification agreement with the Company to which I am a party, the charter, bylaws, or operating agreements of the Company, or under applicable law; (b) any rights or claims to unemployment
compensation, funds accrued in my 401k account, or any vested equity incentives; (c) any rights that are not waivable as a matter of law; or (d) any claims arising from the breach of this Agreement. I hereby represent and warrant that,
other than the Excluded Claims, I am not aware of any claims I have or might have against any of the Released Parties that are not included in the Released Claims. 

I also acknowledge that I have read and understand Section 1542 of the California Civil Code which reads as follows: “A general
release does not extend to claims which the creditor does not know or suspect to exist in his or her favor at the time of executing the release, which if known by him or her must have materially affected his or her settlement with the
debtor.” I hereby expressly waive and relinquish all rights and benefits under that Section and any law of any jurisdiction of similar effect with respect to any claims I may have against the Company. 

  
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 I acknowledge that, among other rights, I am waiving and releasing any rights I may have under
ADEA, that this Release and Waiver is knowing and voluntary, and that the consideration given for this Release and Waiver is in addition to anything of value to which I was already entitled as an executive of the Company. If I am 40 years of age or
older upon execution of this Release and Waiver, I further acknowledge that I have been advised, as required by the Older Workers Benefit Protection Act, that: (a) the release and waiver granted herein does not relate to claims under the ADEA
which may arise after this Release and Waiver is executed; (b) I should consult with an attorney prior to executing this Release and Waiver; and (c) I have twenty-one (21) days from the date of termination of my employment with the
Company in which to consider this Release and Waiver (although I may choose voluntarily to execute this Release and Waiver earlier); (d) I have seven (7) days following the execution of this Release and Waiver to revoke my consent to this
Release and Waiver; and (e) this Release and Waiver shall not be effective until the seven (7) day revocation period has expired without my having previously revoked this Release and Waiver. 

I acknowledge my continuing obligations under my Proprietary Information and Inventions Agreement. Pursuant to the Proprietary Information and
Inventions Agreement I understand that among other things, I must not use or disclose any confidential or proprietary information of the Company and I must immediately return all Company property and documents (including all embodiments of
proprietary information) and all copies thereof in my possession or control. I understand and agree that my right to the severance pay I am receiving in exchange for my agreement to the terms of this Release and Waiver is contingent upon my
continued compliance with my Proprietary Information and Inventions Agreement. 
 This Release and Waiver constitutes the complete, final
and exclusive embodiment of the entire agreement between the Company and me with regard to the subject matter hereof. I am not relying on any promise or representation by the Company that is not expressly stated herein. This Release and Waiver may
only be modified by a writing signed by both me and a duly authorized officer of the Company. 
  

									
	Date:	 	  
	 		 	By:	 	  

		 		 		 		 	Athena Countouriotis


  
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