Document:

2011 Equity Incentive Plan and Form of Stock Option Agreement

 Exhibit 10.3 
 CEMPRA, INC. 
 2011 EQUITY INCENTIVE PLAN 

Approved by the Board: October 11, 2011 
 Approved by the Stockholders:                     , 2011 

Termination Date:
                    , 2021 
  

	1.	GENERAL.

 (a)
Establishment. Cempra, Inc., a Delaware corporation, hereby establishes the Cempra, Inc. 2011 Equity Incentive Plan (as may be amended from time to time, the “Plan”) effective as
of                     , 2011, the date of its approval by the stockholders of the Company (the “Effective
Date”). 
 (b) Successor to Prior Plan. This Plan is intended as the
successor to the Company’s Sixth Amended and Restated 2006 Stock Plan (the “Prior Plan”). Following the Effective Date, no additional stock awards shall be granted under the Prior Plan. Any shares remaining available for
issuance pursuant to the exercise of options or settlement of stock awards under the Prior Plan shall become available for issuance pursuant to Stock Awards granted hereunder, as provided in Section 3(a) hereof. Any shares subject to
outstanding stock awards granted under the Prior Plan that expire or terminate for any reason prior to exercise or settlement shall become available for issuance pursuant to Stock Awards granted hereunder, as provided in Section 3(b) hereof.
All outstanding stock awards granted under the Prior Plan shall remain subject to the terms of the Prior Plan with respect to which they were originally granted. 
 (c) Eligible Award Recipients. The persons eligible to receive Stock Awards are Employees, Directors and Consultants. 
 (d) Available Awards. The Plan provides for the grant of the following Stock Awards: (i) Incentive Stock Options, (ii) Nonstatutory Stock Options, (iii) Restricted Stock Awards,
(iv) Restricted Stock Unit Awards, (v) Stock Appreciation Rights, (vi) Performance Stock Awards and (vii) Other Stock Awards. 
 (e) Purpose. The purpose of the Plan is to advance the interests of the Company and its stockholders by providing an incentive to attract, retain and reward persons eligible to receive Stock
Awards as set forth in Section 1(c), and by motivating such persons to contribute to the growth and profitability of the Company. 
  

	2.	ADMINISTRATION.

 (a)
Administration by Board. The Board shall administer the Plan unless and until the Board delegates administration of the Plan to a Committee or Committees, as provided in Section 2(c). 

(b) Powers of Board. The Board shall have the power, subject to, and within the limitations of, the express provisions of the
Plan: 
 (i) To determine from time to time (A) which of the persons eligible under the Plan shall be
granted Stock Awards; (B) when and how each Stock Award shall be granted; (C) what type or combination of types of Stock Awards shall be granted; (D) the provisions of each Stock Award granted (which need not be identical), including
the time or times when a person shall be permitted to receive cash or Common Stock pursuant to a Stock Award; and (E) the number of shares of Common Stock with 

 
respect to which a Stock Award shall be granted to each such person. 
 (ii) To determine the provisions of each Stock Award granted (which need not be identical), including without limitation, (A) the exercise or purchase price of shares of Common Stock purchased
pursuant to any Stock Award, (B) the method of payment for shares of Common Stock purchased pursuant to any Stock Award, (C) the method for satisfaction of any tax withholding obligation arising in connection with Stock Award, including by
the withholding or delivery of shares of Common Stock, (D) the timing, terms and conditions of the exercisability or vesting of any Stock Award or any shares acquired pursuant thereto, (E) the Performance Criteria necessary to satisfy
Performance Goals applicable to any Stock Award and the extent to which such Performance Goals have been attained, (F) the time of the expiration of any Stock Award, (G) the effect of the Participant’s termination of Continuous
Service on any of the foregoing, and (H) all other terms, conditions and restrictions applicable to any Stock Award or shares acquired pursuant thereto not inconsistent with the terms of the Plan. 

(iii) To construe and interpret the Plan and Stock Awards granted under it, and to establish, amend and revoke
rules and regulations for its administration. The Board, in the exercise of this power, may correct any defect, omission or inconsistency in the Plan or in any Stock Award Agreement, in a manner and to the extent it shall deem necessary or expedient
to make the Plan or Stock Award fully effective. 
 (iv) To settle all controversies regarding the Plan
and Stock Awards granted under it. 
 (v) To accelerate, continue, extend or defer the time at which a
Stock Award may first be exercised or the time during which a Stock Award or any part thereof will vest in accordance with the Plan, notwithstanding the provisions in the Stock Award stating the time at which it may first be exercised or the time
during which it will vest. 
 (vi) To suspend or terminate the Plan at any time. Suspension or termination
of the Plan shall not impair rights and obligations under any Stock Award granted while the Plan is in effect except with the written consent of the affected Participant. 

(vii) To amend the Plan in any respect the Board deems necessary or advisable, including, without limitation,
relating to Incentive Stock Options and certain nonqualified deferred compensation under Section 409A of the Code and/or to bring the Plan or Stock Awards granted under the Plan into compliance therewith, subject to the limitations, if any, of
applicable law. However, except as provided in Section 9(a) relating to Capitalization Adjustments, stockholder approval shall be required for any amendment of the Plan that either (A) materially increases the number of shares of Common
Stock available for issuance under the Plan, (B) materially expands the class of individuals eligible to receive Stock Awards under the Plan, (C) materially increases the benefits accruing to Participants under the Plan or materially
reduces the price at which shares of Common Stock may be issued or purchased under the Plan, (D) materially extends the term of the Plan, or (E) expands the types of Stock Awards available for issuance under the Plan, but in each of
(A) through (E) only to the extent required by applicable law or listing requirements. Except as provided above, rights under any Stock Award granted before amendment of the Plan shall not be impaired by any amendment of the Plan unless
(1) the Company requests the consent of the affected Participant, and (2) such Participant consents in writing. 
 (viii) To submit any amendment to the Plan for stockholder approval, including, but not limited to, amendments to the Plan intended to satisfy the requirements of (A) Section 162(m) of
the Code and the regulations thereunder regarding the exclusion of performance-based compensation from the limit on corporate deductibility of compensation paid to Covered Employees, (B) Section 422 of the Code regarding Incentive Stock
Options, or (C) Rule 16b-3. 

  
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 (ix) To approve forms of Stock Award Agreements for use under the
Plan and to amend the terms of any one or more Stock Awards, including, but not limited to, amendments to provide terms more favorable than previously provided in the Stock Award Agreement, subject to any specified limits in the Plan that are not
subject to Board discretion; provided however, that a Participant’s rights under any Stock Award shall not be impaired by any such amendment unless (A) the Company requests the consent of the affected Participant, and (B) such
Participant consents in writing. Notwithstanding the foregoing, subject to the limitations of applicable law, if any, the Board may amend the terms of any one or more Stock Awards without the affected Participant’s consent if necessary to
maintain the qualified status of the Stock Award as an Incentive Stock Option or to bring the Stock Award into compliance with Section 409A of the Code and the related guidance thereunder. 

(x) Generally, to exercise such powers and to perform such acts as the Board deems necessary or expedient to
promote the best interests of the Company and that are not in conflict with the provisions of the Plan or Stock Awards. 
 (xi) To adopt such procedures and sub-plans as are necessary or appropriate to permit participation in the Plan by Employees, Directors or Consultants who are foreign nationals or employed outside
the United States. 
 (xii) To effect, at any time and from time to time, with the consent of any
adversely affected Participant, (A) the reduction of the exercise price (or strike price) of any outstanding Option or Stock Appreciation Right under the Plan; (B) the cancellation of any outstanding Option or Stock Appreciation Right
under the Plan and the grant in substitution therefor of (1) a new Option or Stock Appreciation Right under the Plan or another equity plan of the Company covering the same or a different number of shares of Common Stock, (2) a Restricted
Stock Award, (3) a Restricted Stock Unit Award, (4) an Other Stock Award, (5) cash and/or (6) other valuable consideration (as determined by the Board, in its sole discretion); or (C) any other action that is treated as a
repricing under generally accepted accounting principles. 
 (c) Delegation to Committee.

(i) General. The Board may delegate some or all of the administration of the Plan to a Committee or
Committees. If administration is delegated to a Committee, the Committee shall have, in connection with the administration of the Plan, the powers theretofore possessed by the Board that have been delegated to the Committee, including the power to
delegate to a subcommittee of the Committee any of the administrative powers the Committee is authorized to exercise (and references in the Plan to the Board shall thereafter be to the Committee or subcommittee), subject, however, to such
resolutions, not inconsistent with the provisions of the Plan, as may be adopted from time to time by the Board. The Board may retain the authority to concurrently administer the Plan with the Committee and may, at any time, revest in the Board some
or all of the powers previously delegated. 
 (ii) Section 162(m) and Rule 16b-3
Compliance. In the sole discretion of the Board, the Committee may consist solely of two or more Outside Directors, in accordance with Section 162(m) of the Code, or solely of two or more Non-Employee Directors, in accordance with
Rule 16b-3. In addition, the Board or the Committee, in its sole discretion, may (A) delegate to a Committee who need not be Outside Directors the authority to grant Stock Awards to eligible persons who are either (I) not then Covered
Employees and are not expected to be Covered Employees at the time of recognition of income resulting from such Stock Award, or (II) not persons with respect to whom the Company wishes to comply with Section 162(m) of the Code, or
(B) delegate to a Committee who need not be Non-Employee Directors the authority to grant Stock Awards to eligible persons who are not then 

  
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subject to Section 16 of the Exchange Act. 
 (d) Delegation to
Officers. The Board may delegate to one or more Officers the authority to do one or both of the following (i) designate Employees of the Company or any of its Subsidiaries to be recipients of Options (and, to the extent permitted by
Delaware law, other Stock Awards) and the terms thereof, and (ii) determine the number of shares of Common Stock to be subject to such Stock Awards granted to such Employees; provided, however, that the Board resolutions regarding such
delegation shall specify the total number of shares of Common Stock that may be subject to the Stock Awards granted by such Officer and that such Officer may not grant a Stock Award to himself or herself. Notwithstanding anything to the contrary in
this Section 2(d), the Board may not delegate to an Officer authority to determine the Fair Market Value of the Common Stock pursuant to Section 12(u)(ii) below. 

(e) Repricing. The Board shall not approve a program providing for either (a) the cancellation of outstanding Stock Awards
and the grant in substitution therefor of new Stock Awards having a lower exercise or purchase price or (b) the amendment of outstanding Stock Awards to reduce the exercise price thereof, unless the stockholders of the Company have approved
such an action within twelve (12) months prior to such an event. This paragraph shall not be construed to apply to “issuing or assuming a stock option in a transaction to which section 424(a) applies,” within the meaning of
Section 424 of the Code.
 (f) Effect of Board’s Decision. All determinations, interpretations and
constructions made by the Board in good faith shall not be subject to review by any person and shall be final, binding and conclusive on all persons. 
 (g) Indemnification. In addition to such other rights of indemnification as they may have as members of the Board or the Committee or as officers or employees of the Company, members of the Board
or the Committee and any officers or employees of the Company to whom authority to act for the Board, the Committee or the Company is delegated shall be indemnified by the Company against all reasonable expenses, including attorneys’ fees,
actually and necessarily incurred in connection with the defense of any action, suit or proceeding, or in connection with any appeal therein, to which they or any of them may be a party by reason of any action taken or failure to act under or in
connection with the Plan, or any right granted hereunder, and against all amounts paid by them in settlement thereof (provided such settlement is approved by independent legal counsel selected by the Company) or paid by them in satisfaction of a
judgment in any such action, suit or proceeding, except in relation to matters as to which it shall be adjudged in such action, suit or proceeding that such person is liable for gross negligence, bad faith or intentional misconduct in duties;
provided, however, that within sixty (60) days after the institution of such action, suit or proceeding, such person shall offer to the Company, in writing, the opportunity at its own expense to handle and defend the same. 

 

	3.	SHARES SUBJECT TO THE PLAN.

(a) Share Reserve. Subject to the provisions of Section 9(a) relating to Capitalization Adjustments, the aggregate number
of shares of Common Stock that may be issued pursuant to Stock Awards under the Plan is equal to fourteen million five hundred thousand (14,500,000) shares (the “Share Reserve”). In addition, the number of shares of
Common Stock available for issuance under the Plan shall automatically increase on January 1st of each year for a period of nine (9) years commencing on January 1, 2013 and ending on (and including) January 1, 2021, in an amount
equal to the lesser of (i) four percent (4%) of the total number of shares of Common Stock outstanding on December 31st of the preceding calendar year, or (ii) one million 

  
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(1,000,000) shares. Notwithstanding the foregoing, the Board may act prior to the first day of any calendar year, to provide that there shall be no increase in the share reserve for such calendar
year or that the increase in the share reserve for such calendar year shall be a lesser number of shares of Common Stock than would otherwise occur pursuant to the preceding sentence. For clarity, the limitation in this Section 3(a) is a
limitation in the number of shares of Common Stock that may be issued pursuant to the Plan. Accordingly, this Section 3(a) does not limit the granting of Stock Awards except as provided in Section 7(a). Shares may be issued in connection
with a merger or acquisition as permitted by, as applicable, NASDAQ Marketplace Rule 4350(i)(1)(A)(iii), NYSE Listed Company Manual Section 303A.08, AMEX Company Guide Section 711 or other applicable stock exchange rules, and such issuance
shall not reduce the number of shares available for issuance under the Plan. If an outstanding Stock Award for any reason expires or is terminated or canceled without having been exercised or settled in full, or if shares of Common Stock acquired
pursuant to a Stock Award subject to forfeiture or repurchase are forfeited or repurchased by the Company at the Participant’s purchase price to effect a forfeiture of unvested shares upon termination of Continuous Service, the shares of Common
Stock allocable to the terminated portion of such Stock Award or such forfeited or repurchased shares of Common Stock shall be added back to the Share Reserve and again be available for issuance under the Plan. Shares of Common Stock shall not be
deemed to have been issued pursuant to the Plan with respect to any portion of a Stock Award (other than a Stock Appreciation Right that may be settled in shares of Common Stock and/or cash) that is settled in cash. Shares withheld in satisfaction
of tax withholding obligations pursuant to Section 8(g) shall not again become available for issuance under the Plan. Upon exercise of a Stock Appreciation Right, whether in cash or shares of Common Stock, the number of shares available for
issuance under the Plan shall be reduced by the gross number of shares for which the Stock Appreciation Right is exercised. If the exercise price of an Option is paid by “net exercise” (as described in Section 5(c)(iv)) or tender to
the Company, or attestation to the ownership, of shares of Common Stock owned by the Participant, the number of shares available for issuance under the Plan shall be reduced by the gross number of shares for which the Option is exercised.

 (b) Additions to the Share Reserve. The Share Reserve also shall be increased from time to time by a number of
shares equal to the number of shares of Common Stock that (i) are issuable pursuant to awards outstanding under the Prior Plan as of the Effective Date and (ii) but for the termination of the Prior Plan as of the Effective Date, would
otherwise have reverted to the share reserve of the Prior Plan pursuant to the provisions thereof. 
 (c) Incentive Stock
Option Limit. Notwithstanding anything to the contrary in this Section 3(c), subject to the provisions of Section 9(a) relating to Capitalization Adjustments, the aggregate maximum number of shares of Common Stock that may be
issued pursuant to the exercise of Incentive Stock Options shall be fourteen million five hundred thousand (14,500,000) shares of Common Stock. 
 (d) Source of Shares. The stock issuable under the Plan shall be shares of authorized but unissued or reacquired Common Stock, including shares repurchased by the Company on the open market.

  

	4.	ELIGIBILITY.

 (a)
Eligibility for Specific Stock Awards. Incentive Stock Options may be granted only to Employees. Stock Awards other than Incentive Stock Options may be granted to Employees, Directors and Consultants. 

(b) Ten Percent Stockholders. A Ten Percent Stockholder shall not be granted an Incentive

  
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Stock Option unless the exercise price of such Option is at least one hundred ten percent (110%) of the Fair Market Value of the Common Stock on the date of grant and the Option is not
exercisable after the expiration of five (5) years from the date of grant. 
 (c) Section 162(m)
Limitation. Subject to the provisions of Section 9(a) relating to Capitalization Adjustments, at such time as the Company may be subject to the applicable provisions of Section 162(m) of the Code, no Employee shall be eligible to
be granted during any calendar year Stock Awards whose value is determined by reference to an increase over an exercise or strike price of at least one hundred percent (100%) of the Fair Market Value of the Common Stock on the date the Stock
Award is granted covering more than seven million two hundred fifty thousand (7,250,000) shares of Common Stock. 
 (d)
Consultants. A Consultant shall be eligible for the grant of a Stock Award only if, at the time of grant, a Form S-8 Registration Statement under the Securities Act (“Form S-8” ) is available to
register either the offer or the sale of the Company’s securities to such Consultant. 
  

	5.	OPTION PROVISIONS.

 Each
Option shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. All Options shall be separately designated Incentive Stock Options or Nonstatutory Stock Options at the time of grant, and, if certificates
are issued, a separate certificate or certificates shall be issued for shares of Common Stock purchased on exercise of each type of Option. If an Option is not specifically designated as an Incentive Stock Option, then the Option shall be a
Nonstatutory Stock Option. The provisions of separate Options need not be identical; provided, however, that each Option Agreement shall conform to (through incorporation of provisions hereof by reference in the Option Agreement or otherwise)
the substance of each of the following provisions: 
 (a) Term. Subject to the provisions of Section 4(b)
regarding Ten Percent Stockholders, no Option shall be exercisable after the expiration of ten (10) years from the date of its grant or such shorter period specified in the Option Agreement. 

(b) Exercise Price. Subject to the provisions of Section 4(b) regarding Ten Percent Stockholders, the exercise price of
each Option shall be not less than one hundred percent (100%) of the Fair Market Value of the Common Stock subject to the Option on the date the Option is granted. Notwithstanding the foregoing, an Option may be granted with an exercise price
lower than one hundred percent (100%) of the Fair Market Value of the Common Stock subject to the Option if such Option is granted pursuant to an assumption or substitution for another option in a manner consistent with the provisions of
Section 409A and Section 424(a) of the Code (whether or not such options are Incentive Stock Options). 
 (c)
Consideration. The purchase price of Common Stock acquired pursuant to the exercise of an Option shall be paid, to the extent permitted by applicable law and as determined by the Board in its sole discretion, by any combination of the
methods of payment set forth below. The Board shall have the authority to grant Options that do not permit all of the following methods of payment (or otherwise restrict the ability to use certain methods) and to grant Options that require the
consent of the Company to utilize a particular method of payment. The methods of payment permitted by this Section 5(c) are: 
 (i) by cash, check, bank draft or money order payable to the Company; 
 (ii) pursuant to a program developed under Regulation T as promulgated by the Federal Reserve Board that, prior to the issuance of the stock subject to the Option, results in either the
receipt of cash (or check) by the Company or the receipt of irrevocable instructions to pay the aggregate 

  
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exercise price to the Company from the sales proceeds; 

(iii) by delivery to the Company (either by actual delivery or attestation) of shares of Common Stock; 

(iv) by a “net exercise” arrangement pursuant to which the Company will reduce the number of shares of
Common Stock issuable upon exercise by the largest whole number of shares with a Fair Market Value that does not exceed the aggregate exercise price; provided, however, that the Company shall accept a cash or other payment from the
Participant to the extent of any remaining balance of the aggregate exercise price not satisfied by such reduction in the number of whole shares to be issued; provided, further, that shares of Common Stock will no longer be subject to an
Option and will not be exercisable thereafter to the extent that (A) shares issuable upon exercise are reduced to pay the exercise price pursuant to the “net exercise,” (B) shares are delivered to the Participant as a result of
such exercise, and (C) shares are withheld to satisfy tax withholding obligations; or 
 (v) in any
other form of legal consideration that may be acceptable to the Board in its sole discretion and permissible under applicable law. 
 (d) Transferability of Options. The Board may, in its sole discretion, impose such limitations on the transferability of Options as the Board shall determine. In the absence of such a
determination by the Board to the contrary, the following restrictions on the transferability of Options shall apply: 
 (i) Restrictions on Transfer. An Option shall not be transferable except by will or by the laws of descent and distribution and shall be exercisable during the lifetime of the Optionholder only by
the Optionholder; provided, however, that the Board may, in its sole discretion, permit transfer of the Option in a manner that is not prohibited by applicable tax and securities laws upon the Optionholder’s request. 

(ii) Domestic Relations Orders. Notwithstanding the foregoing, an Option may be transferred pursuant to a domestic
relations order, provided, however, that if an Option is an Incentive Stock Option, such Option may be deemed to be a Nonstatutory Stock Option as a result of such transfer. 

(iii) Beneficiary Designation. Notwithstanding the foregoing, the Optionholder may, by delivering written notice to
the Company, in a form provided by or otherwise satisfactory to the Company and any broker designated by the Company to effect Option exercises, designate a third party who, in the event of the death of the Optionholder, shall thereafter be entitled
to exercise the Option. In the absence of such a designation, the executor or administrator of the Optionholder’s estate shall be entitled to exercise the Option. 
 (e) Vesting of Options Generally. The total number of shares of Common Stock subject to an Option may vest and therefore become exercisable in periodic installments that may or may not be
equal. The Option may be subject to such other terms and conditions on the time or times when it may or may not be exercised (which may be based on the satisfaction of Performance Goals or other criteria) as the Board may deem appropriate. The
vesting provisions of individual Options may vary. The provisions of this Section 5(e) are subject to any Option provisions governing the minimum number of shares of Common Stock as to which an Option may be exercised. 

(f) Termination of Continuous Service. In the event that an Optionholder’s Continuous Service terminates (other than for
Cause or upon the Optionholder’s death or Disability), the Optionholder may exercise his or her Option (to the extent that the Optionholder was entitled to exercise such Option as 

  
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of the date of termination of Continuous Service) but only within such period of time ending on the earlier of (i) the date three (3) months following the termination of the
Optionholder’s Continuous Service (or such longer or shorter period specified in the Option Agreement), or (ii) the expiration of the term of the Option as set forth in the Option Agreement. If, after termination of Continuous Service, the
Optionholder does not exercise his or her Option within the time specified herein or in the Option Agreement (as applicable), the Option shall terminate. 
 (g) Extension of Termination Date. An Optionholder’s Option Agreement may provide that if the exercise of the Option following the termination of the Optionholder’s Continuous
Service (other than for Cause or upon the Optionholder’s death or Disability) would be prohibited at any time solely because the issuance of shares of Common Stock would violate the registration requirements under the Securities Act, then the
Option shall terminate on the earlier of (i) the expiration of a period of three (3) months after the termination of the Optionholder’s Continuous Service during which the exercise of the Option would not be in violation of such
registration requirements, or (ii) the expiration of the term of the Option as set forth in the Option Agreement. In addition, unless otherwise provided in an Optionholder’s Option Agreement, if the sale of the Common Stock received upon
exercise of an Option following the termination of the Optionholder’s Continuous Service (other than for Cause) would violate the Company’s Insider Trading Policy, then the Option shall terminate on the earlier of (i) the expiration
of a period equal to the post-termination exercise period described in Section 5(f) above or Sections 5(h) or 5(i) below after the termination of the Optionholder’s Continuous Service during which the exercise of the Option would not
be in violation of the Company’s Insider Trading Policy; or (ii) the expiration of the term of the Option as set forth in the Option Agreement. 
 (h) Disability of Optionholder. In the event that an Optionholder’s Continuous Service terminates as a result of the Optionholder’s Disability, the Optionholder may exercise his or
her Option (to the extent that the Optionholder was entitled to exercise such Option as of the date of termination of Continuous Service), but only within such period of time ending on the earlier of (i) the date twelve (12) months
following such termination of Continuous Service (or such longer or shorter period specified in the Option Agreement), or (ii) the expiration of the term of the Option as set forth in the Option Agreement. If, after termination of Continuous
Service, the Optionholder does not exercise his or her Option within the time specified herein or in the Option Agreement (as applicable), the Option shall terminate. 
 (i) Death of Optionholder. In the event that (i) an Optionholder’s Continuous Service terminates as a result of the Optionholder’s death, or (ii) the Optionholder dies
within the period (if any) specified in the Option Agreement after the termination of the Optionholder’s Continuous Service for a reason other than death, then the Option may be exercised (to the extent the Optionholder was entitled to exercise
such Option as of the date of death) by the Optionholder’s estate, by a person who acquired the right to exercise the Option by bequest or inheritance or by a person designated to exercise the option upon the Optionholder’s death, but only
within the period ending on the earlier of (A) the date twelve (12) months following the date of death (or such longer or shorter period specified in the Option Agreement), or (B) the expiration of the term of such Option as set forth
in the Option Agreement. If, after the Optionholder’s death, the Option is not exercised within the time specified herein or in the Option Agreement (as applicable), the Option shall terminate. 

(j) Termination for Cause. Except as explicitly provided otherwise in an Optionholder’s Option Agreement, in the event
that an Optionholder’s Continuous Service is terminated for Cause, the Option shall terminate upon the termination date of such Optionholder’s Continuous Service, and the Optionholder shall be prohibited from exercising his or her Option
from and after the time of such termination of Continuous Service. 

  
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 (k) Non-Exempt Employees. No Option granted to an Employee who is a non-exempt
employee for purposes of the Fair Labor Standards Act shall be first exercisable for any shares of Common Stock until at least six months following the date of grant of the Option. The foregoing provision is intended to operate so that any income
derived by a non-exempt employee in connection with the exercise or vesting of an Option will be exempt from his or her regular rate of pay. 
  

	6.	PROVISIONS OF STOCK AWARDS OTHER THAN OPTIONS.

 (a) Restricted Stock Awards. Each Restricted Stock Award Agreement shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. To the extent
consistent with the Company’s Bylaws, at the Board’s election, shares of Common Stock may be (x) held in book entry form subject to the Company’s instructions until any restrictions relating to the Restricted Stock Award lapse;
or (y) evidenced by a certificate, which certificate shall be held in such form and manner as determined by the Board. The terms and conditions of Restricted Stock Award Agreements may change from time to time, and the terms and conditions of
separate Restricted Stock Award Agreements need not be identical, provided, however, that each Restricted Stock Award Agreement shall conform to (through incorporation of the provisions hereof by reference in the agreement or otherwise) the
substance of each of the following provisions: 
 (i) Consideration. A Restricted Stock Award may be
awarded in consideration for (A) cash, check, bank draft or money order payable to the Company; (B) past or future services actually or to be rendered to the Company or an Affiliate; or (C) any other form of legal consideration that
may be acceptable to the Board in its sole discretion and permissible under applicable law. 
 (ii)
Vesting. Shares of Common Stock awarded under a Restricted Stock Award Agreement may be subject to forfeiture to the Company in accordance with a vesting schedule to be determined by the Board. 

(iii) Termination of Participant’s Continuous Service. In the event a Participant’s Continuous
Service terminates, the Company may receive via a forfeiture condition or a repurchase right, any or all of the shares of Common Stock held by the Participant which have not vested as of the date of termination of Continuous Service under the terms
of the Restricted Stock Award Agreement. 
 (iv) Transferability. Rights to acquire shares of Common
Stock under the Restricted Stock Award Agreement shall be transferable by the Participant only upon such terms and conditions as are set forth in the Restricted Stock Award Agreement, as the Board shall determine in its sole discretion, so long as
Common Stock awarded under the Restricted Stock Award Agreement remains subject to the terms of the Restricted Stock Award Agreement. 
 (b) Restricted Stock Unit Awards. Each Restricted Stock Unit Award Agreement shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. The terms
and conditions of Restricted Stock Unit Award Agreements may change from time to time, and the terms and conditions of separate Restricted Stock Unit Award Agreements need not be identical, provided, however, that each Restricted Stock Unit
Award Agreement shall conform to (through incorporation of the provisions hereof by reference in the agreement or otherwise) the substance of each of the following provisions: 

(i) Consideration. At the time of grant of a Restricted Stock Unit Award, the Board will determine the
consideration, if any, to be paid by the Participant upon delivery of each share of Common Stock subject to the Restricted Stock Unit Award. The consideration to be paid (if any) by the Participant for each share of Common Stock subject to a
Restricted Stock Unit Award may be paid in any 

  
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form of legal consideration that may be acceptable to the Board in its sole discretion and permissible under applicable law. 

(ii) Vesting. At the time of the grant of a Restricted Stock Unit Award, the Board may impose such
restrictions or conditions to the vesting of the Restricted Stock Unit Award as it, in its sole discretion, deems appropriate. 
 (iii) Payment. A Restricted Stock Unit Award may be settled by the delivery of shares of Common Stock, their cash equivalent, any combination thereof or in any other form of consideration, as
determined by the Board and contained in the Restricted Stock Unit Award Agreement. 
 (iv) Additional
Restrictions. At the time of the grant of a Restricted Stock Unit Award, the Board, as it deems appropriate, may impose such restrictions or conditions that delay the delivery of the shares of Common Stock (or their cash equivalent) subject
to a Restricted Stock Unit Award to a time after the vesting of such Restricted Stock Unit Award. 
 (v)
Dividend Equivalents. Dividend equivalents may be credited in respect of shares of Common Stock covered by a Restricted Stock Unit Award, as determined by the Board and contained in the Restricted Stock Unit Award Agreement. At the sole
discretion of the Board, such dividend equivalents may be converted into additional shares of Common Stock covered by the Restricted Stock Unit Award in such manner as determined by the Board. Any additional shares covered by the Restricted Stock
Unit Award credited by reason of such dividend equivalents will be subject to all the terms and conditions of the underlying Restricted Stock Unit Award Agreement to which they relate. 

(vi) Termination of Participant’s Continuous Service. Except as otherwise provided in the applicable
Restricted Stock Unit Award Agreement, such portion of the Restricted Stock Unit Award that has not vested will be forfeited upon the Participant’s termination of Continuous Service. 

(vii) Compliance with Section 409A of the Code. Notwithstanding anything to the contrary set forth
herein, any Restricted Stock Unit Award granted under the Plan that is not exempt from the requirements of Section 409A of the Code shall incorporate terms and conditions necessary to avoid the consequences of Section 409A(a)(1) of the
Code. Such restrictions, if any, shall be determined by the Board and contained in the Restricted Stock Unit Award Agreement evidencing such Restricted Stock Unit Award. 
 (c) Stock Appreciation Rights. Each Stock Appreciation Right Agreement shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. Stock Appreciation
Rights may be granted as stand-alone Stock Awards or in tandem with other Stock Awards. The terms and conditions of Stock Appreciation Right Agreements may change from time to time, and the terms and conditions of separate Stock Appreciation Right
Agreements need not be identical; provided, however, that each Stock Appreciation Right Agreement shall conform to (through incorporation of the provisions hereof by reference in the agreement or otherwise) the substance of each of the
following provisions: 
 (i) Term. No Stock Appreciation Right shall be exercisable after the
expiration of ten (10) years from the date of its grant or such shorter period specified in the Stock Appreciation Right Agreement. 
 (ii) Strike Price. Each Stock Appreciation Right will be denominated in shares of Common Stock equivalents. The strike price of each Stock Appreciation Right shall not be less than one hundred
percent (100%) of the Fair Market Value of the Common Stock equivalents subject to the Stock 

  
 10 

 
Appreciation Right on the date of grant. 
 (iii)
Calculation of Appreciation. The appreciation distribution payable on the exercise of a Stock Appreciation Right will be not greater than an amount equal to the excess of (A) the aggregate Fair Market Value (on the date of the exercise
of the Stock Appreciation Right) of a number of shares of Common Stock equal to the number of shares of Common Stock equivalents in which the Participant is vested under such Stock Appreciation Right, and with respect to which the Participant is
exercising the Stock Appreciation Right on such date, over (B) the strike price. 
 (iv)
Vesting. At the time of the grant of a Stock Appreciation Right, the Board may impose such restrictions or conditions to the vesting of such Stock Appreciation Right as it, in its sole discretion, deems appropriate. 

(v) Exercise. To exercise any outstanding Stock Appreciation Right, the Participant must provide written
notice of exercise to the Company in compliance with the provisions of the Stock Appreciation Right Agreement evidencing such Stock Appreciation Right. 
 (vi) Payment. The appreciation distribution in respect of a Stock Appreciation Right may be paid in Common Stock, in cash, in any combination of the two or in any other form of consideration,
as determined by the Board and set forth in the Stock Appreciation Right Agreement evidencing such Stock Appreciation Right. 
 (vii) Termination of Continuous Service. In the event that a Participant’s Continuous Service terminates (other than for Cause), the Participant may exercise his or her Stock Appreciation
Right (to the extent that the Participant was entitled to exercise such Stock Appreciation Right as of the date of termination of Continuous Service) but only within such period of time ending on the earlier of (A) the date three
(3) months following the termination of the Participant’s Continuous Service (or such longer or shorter period specified in the Stock Appreciation Right Agreement), or (B) the expiration of the term of the Stock Appreciation Right as
set forth in the Stock Appreciation Right Agreement. If, after termination of Continuous Service, the Participant does not exercise his or her Stock Appreciation Right within the time specified herein or in the Stock Appreciation Right Agreement (as
applicable), the Stock Appreciation Right shall terminate. 
 (viii) Termination for Cause. Except as
explicitly provided otherwise in an Participant’s Stock Appreciation Right Agreement, in the event that a Participant’s Continuous Service is terminated for Cause, the Stock Appreciation Right shall terminate upon the termination date of
such Participant’s Continuous Service, and the Participant shall be prohibited from exercising his or her Stock Appreciation Right from and after the time of such termination of Continuous Service. 

(ix) Compliance with Section 409A of the Code. Notwithstanding anything to the contrary set forth herein,
any Stock Appreciation Rights granted under the Plan that are not exempt from the requirements of Section 409A of the Code shall incorporate terms and conditions necessary to avoid the consequences described in Section 409A(a)(1) of the
Code. Such restrictions, if any, shall be determined by the Board and contained in the Stock Appreciation Right Agreement evidencing such Stock Appreciation Right. 
 (d) Performance Stock Awards. A Performance Stock Award is either a Restricted Stock Award or Restricted Stock Unit Award that may be granted or may vest based upon the attainment during a
Performance Period of certain Performance Goals. A Performance Stock Award may, but need not, require the completion of a specified period of Continuous Service. The length of any Performance Period, the Performance Goals to be achieved during the
Performance Period, and the measure of whether 

  
 11 

 
and to what degree such Performance Goals have been attained shall be conclusively determined by the Committee in its sole discretion. Subject to the provisions of Section 9(a) relating to
Capitalization Adjustments, the maximum number of shares that may be granted to any Participant in a calendar year attributable to Performance Stock Awards described in this Section 6(d)(i) shall not exceed seven million two hundred fifty
thousand (7,250,000) shares of Common Stock. In addition, to the extent permitted by applicable law and the applicable Stock Award Agreement, the Board may determine that cash may be used in payment of Performance Stock Awards. 

(e) Other Stock Awards. Other forms of Stock Awards valued in whole or in part by reference to, or otherwise based on, Common
Stock may be granted either alone or in addition to Stock Awards provided for under Section 5 and the preceding provisions of this Section 6. Subject to the provisions of the Plan, the Board shall have sole and complete authority to
determine the persons to whom and the time or times at which such Other Stock Awards will be granted, the number of shares of Common Stock (or the cash equivalent thereof) to be granted pursuant to such Other Stock Awards and all other terms and
conditions of such Other Stock Awards. 
  

	7.	COVENANTS OF THE COMPANY.

(a) Availability of Shares. During the terms of the Stock Awards, the Company shall keep available at all times the number of
shares of Common Stock required to satisfy such Stock Awards. 
 (b) Securities Law Compliance. The Company shall
seek to obtain from each regulatory commission or agency having jurisdiction over the Plan such authority as may be required to grant Stock Awards and to issue and sell shares of Common Stock upon exercise of the Stock Awards; provided,
however, that this undertaking shall not require the Company to register under the Securities Act the Plan, any Stock Award or any Common Stock issued or issuable pursuant to any such Stock Award. If, after reasonable efforts, the Company is
unable to obtain from any such regulatory commission or agency the authority that counsel for the Company deems necessary for the lawful issuance and sale of Common Stock under the Plan, the Company shall be relieved from any liability for failure
to issue and sell Common Stock upon exercise of such Stock Awards unless and until such authority is obtained. 
 (c) No
Obligation to Notify. The Company shall have no duty or obligation to any holder of a Stock Award to advise such holder as to the time or manner of exercising such Stock Award. Furthermore, the Company shall have no duty or obligation to
warn or otherwise advise such holder of a pending termination or expiration of a Stock Award or a possible period in which the Stock Award may not be exercised. The Company has no duty or obligation to minimize the tax consequences of a Stock Award
to the holder of such Stock Award. 
  

	8.	MISCELLANEOUS.

 (a) Use
of Proceeds. Proceeds from the sale of shares of Common Stock pursuant to Stock Awards shall constitute general funds of the Company. 
 (b) Corporate Action Constituting Grant of Stock Awards. Corporate action constituting a grant by the Company of a Stock Award to any Participant shall be deemed completed as of the date of
such corporate action, unless otherwise determined by the Board, regardless of when the instrument, certificate, or letter evidencing the Stock Award is communicated to, or actually received or accepted by, the Participant. 

(c) Stockholder Rights. No Participant shall be deemed to be the holder of, or to have any of the rights of a holder with
respect to, any shares of Common Stock subject to such Stock Award unless 

  
 12 

 
and until (i) such Participant has satisfied all requirements for exercise of the Stock Award pursuant to its terms, and (ii) the issuance of the Common Stock pursuant to such exercise
has been entered into the books and records of the Company. 
 (d) No Employment or Other Service Rights. Nothing in
the Plan, any Stock Award Agreement or other instrument executed thereunder or in connection with any Stock Award granted pursuant to the Plan shall confer upon any Participant any right to continue to serve the Company or an Affiliate in the
capacity in effect at the time the Stock Award was granted or shall affect the right of the Company or an Affiliate to terminate (i) the employment of an Employee with or without notice and with or without Cause, (ii) the service of a
Consultant pursuant to the terms of such Consultant’s agreement with the Company or an Affiliate, or (iii) the service of a Director pursuant to the Bylaws of the Company or an Affiliate, and any applicable provisions of the corporate law
of the state in which the Company or the Affiliate is incorporated, as the case may be. 
 (e) Incentive Stock Option
$100,000 Limitation. To the extent that the aggregate Fair Market Value (determined at the time of grant) of Common Stock with respect to which Incentive Stock Options are exercisable for the first time by any Optionholder during any
calendar year (under all plans of the Company and any Affiliates) exceeds one hundred thousand dollars ($100,000), the Options or portions thereof that exceed such limit (according to the order in which they were granted) shall be treated as
Nonstatutory Stock Options, notwithstanding any contrary provision of the applicable Option Agreement(s). 
 (f) Investment
Assurances. The Company may require a Participant, as a condition of exercising or acquiring Common Stock under any Stock Award, (i) to give written assurances satisfactory to the Company as to the Participant’s knowledge and
experience in financial and business matters and/or to employ a purchaser representative reasonably satisfactory to the Company who is knowledgeable and experienced in financial and business matters and that he or she is capable of evaluating, alone
or together with the purchaser representative, the merits and risks of exercising the Stock Award; and (ii) to give written assurances satisfactory to the Company stating that the Participant is acquiring Common Stock subject to the Stock Award
for the Participant’s own account and not with any present intention of selling or otherwise distributing the Common Stock. The foregoing requirements, and any assurances given pursuant to such requirements, shall be inoperative if (x) the
issuance of the shares upon the exercise or acquisition of Common Stock under the Stock Award has been registered under a then currently effective registration statement under the Securities Act, or (y) as to any particular requirement, a
determination is made by counsel for the Company that such requirement need not be met in the circumstances under the then applicable securities laws. The Company may, upon advice of counsel to the Company, place legends on stock certificates issued
under the Plan as such counsel deems necessary or appropriate in order to comply with applicable securities laws, including, but not limited to, legends restricting the transfer of the Common Stock. 

(g) Withholding Obligations. Unless prohibited by the terms of a Stock Award Agreement, the Company may, in its sole
discretion, satisfy any federal, state or local tax withholding obligation relating to a Stock Award by any of the following means (in addition to the Company’s right to withhold from any compensation paid to the Participant by the Company) or
by a combination of such means: (i) causing the Participant to tender a cash payment; (ii) withholding shares of Common Stock from the shares of Common Stock issued or otherwise issuable to the Participant in connection with the Stock
Award; provided, however, that no shares of Common Stock are withheld with a value exceeding the minimum amount of tax required to be withheld by law (or such lower amount as may be necessary to avoid classification of the Stock Award as a
liability for financial accounting purposes); (iii) withholding cash from a Stock Award settled in cash; (iv) withholding payment from any amounts otherwise payable to the Participant; or (v) by such other method as may be set forth
in the Stock Award Agreement. 

  
 13 

 (h) Electronic Delivery. Any reference herein to a “written” agreement
or document shall include any agreement or document delivered electronically or posted on the Company’s intranet. 
 (i)
Deferrals. To the extent permitted by applicable law, the Board, in its sole discretion, may determine that the delivery of Common Stock or the payment of cash, upon the exercise, vesting or settlement of all or a portion of any Stock Award
may be deferred and may establish programs and procedures for deferral elections to be made by Participants. Deferrals by Participants will be made in accordance with Section 409A of the Code. Consistent with Section 409A of the Code, the
Board may provide for distributions while a Participant is still an employee. The Board is authorized to make deferrals of Stock Awards and determine when, and in what annual percentages, Participants may receive payments, including lump sum
payments, following the Participant’s termination of employment or retirement, and implement such other terms and conditions consistent with the provisions of the Plan and in accordance with applicable law. 

(j) Compliance with Section 409A. To the extent that the Board determines that any Stock Award granted under the Plan is
subject to Section 409A of the Code, the Stock Award Agreement evidencing such Stock Award shall incorporate the terms and conditions necessary to avoid the consequences described in Section 409A(a)(1) of the Code. To the extent
applicable, the Plan and Stock Award Agreements shall be interpreted in accordance with Section 409A of the Code and Department of Treasury regulations and other interpretive guidance issued thereunder, including without limitation any such
regulations or other guidance that may be issued or amended after the Effective Date. Notwithstanding any provision of the Plan to the contrary, in the event that following the Effective Date the Board determines that any Stock Award may be subject
to Section 409A of the Code and related Department of Treasury guidance (including such Department of Treasury guidance as may be issued after the Effective Date), the Board may adopt such amendments to the Plan and the applicable Stock Award
Agreement or adopt other policies and procedures (including amendments, policies and procedures with retroactive effect), or take any other actions, that the Board determines are necessary or appropriate to (1) exempt the Stock Award from
Section 409A of the Code and/or preserve the intended tax treatment of the benefits provided with respect to the Stock Award, or (2) comply with the requirements of Section 409A of the Code and related Department of Treasury guidance.

 9. ADJUSTMENTS UPON CHANGES IN COMMON STOCK; OTHER CORPORATE EVENTS.

(a) Capitalization Adjustments. In the event of a Capitalization Adjustment, the Board shall appropriately and proportionately
adjust: (i) the class(es) and maximum number of securities subject to the Plan pursuant to Section 3(a); (ii) the class(es) and maximum number of securities that may be issued pursuant to the exercise of Incentive Stock Options
pursuant to Section 3(d); (iii) the class(es) and maximum number of securities that may be awarded to any person pursuant to Section 4(c) and 6(d); and (iv) the class(es) and number of securities and price per share of stock
subject to outstanding Stock Awards. The Board shall make such adjustments, and its determination shall be final, binding and conclusive. 
 (b) Dissolution or Liquidation. Except as otherwise provided in a Stock Award Agreement, in the event of a dissolution or liquidation of the Company, all outstanding Stock Awards (other than
Stock Awards consisting of vested and outstanding shares of Common Stock not subject to a forfeiture condition or the Company’s right of repurchase) shall terminate immediately prior to the completion of such dissolution or liquidation, and the
shares of Common Stock subject to the Company’s repurchase rights may be repurchased by the Company notwithstanding the fact that the holder of such Stock Award is providing Continuous Service, provided, however, that the Board may, in
its sole discretion, cause 

  
 14 

 
some or all Stock Awards to become fully vested, exercisable and/or no longer subject to repurchase or forfeiture (to the extent such Stock Awards have not previously expired or terminated)
before the dissolution or liquidation is completed but contingent on its completion. 
 (c) Corporate
Transaction. The following provisions shall apply to Stock Awards in the event of a Corporate Transaction unless otherwise provided in the instrument evidencing the Stock Award or any other written agreement between the Company or any
Affiliate and the holder of the Stock Award. 
 (i) Stock Awards May Be Assumed. Except as otherwise
stated in the Stock Award Agreement, in the event of a Corporate Transaction, any surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company) may assume or continue any or all Stock Awards
outstanding under the Plan or may substitute similar stock awards for Stock Awards outstanding under the Plan (including but not limited to, awards to acquire the same consideration paid to the stockholders of the Company pursuant to the Corporate
Transaction), and any reacquisition or repurchase rights held by the Company in respect of Common Stock issued pursuant to Stock Awards may be assigned by the Company to the successor of the Company (or the successor’s parent company, if any),
in connection with such Corporate Transaction. A surviving corporation or acquiring corporation (or its parent) may choose to assume or continue only a portion of a Stock Award or substitute a similar stock award for only a portion of a Stock Award.
The terms of any assumption, continuation or substitution shall be set by the Board in accordance with the provisions of Section 2 hereof. 
 (ii) Stock Awards Held by Current Participants. Except as otherwise stated in the Stock Award Agreement, in the event of a Corporate Transaction in which the surviving corporation or acquiring
corporation (or its parent company) does not assume or continue such outstanding Stock Awards or substitute similar stock awards for such outstanding Stock Awards in accordance with subsection (i) above, then with respect to Stock Awards that
have not been assumed, continued or substituted and that are held by Participants whose Continuous Service has not terminated prior to the effective time of the Corporate Transaction (referred to as the “Current Participants”
), the vesting of such Stock Awards (and, with respect to Options and Stock Appreciation Rights, the time at which such Stock Awards may be exercised) shall (contingent upon the effectiveness of the Corporate Transaction) be accelerated in
full to a date prior to the effective time of such Corporate Transaction as the Board shall determine (or, if the Board shall not determine such a date, to the date that is five (5) days prior to the effective time of the Corporate
Transaction), and such Stock Awards shall terminate if not exercised (if applicable) at or prior to the effective time of the Corporate Transaction, and any reacquisition or repurchase rights held by the Company with respect to such Stock Awards
shall lapse (contingent upon the effectiveness of the Corporate Transaction). 
 (iii) Stock Awards Held by
Persons other than Current Participants. Except as otherwise stated in the Stock Award Agreement, in the event of a Corporate Transaction in which the surviving corporation or acquiring corporation (or its parent company) does not assume or
continue such outstanding Stock Awards or substitute similar stock awards for such outstanding Stock Awards in accordance with subsections (i) or (ii) above, respectively, then with respect to Stock Awards that have not been assumed,
continued or substituted and that are held by persons other than Current Participants, the vesting of such Stock Awards (and, if applicable, the time at which such Stock Award may be exercised) shall not be accelerated and such Stock Awards (other
than a Stock Award consisting of vested and outstanding shares of Common Stock not subject to a forfeiture condition or the Company’s right of repurchase) shall terminate if not exercised (if applicable) prior to the effective time of the
Corporate Transaction; provided, however, that any reacquisition or repurchase rights held by the Company with respect to such Stock Awards shall not terminate and may continue to be exercised notwithstanding the Corporate Transaction.

  
 15 

 (iv) Payment for Stock Awards in Lieu of
Exercise. Notwithstanding the foregoing, in the event a Stock Award will terminate if not exercised prior to the effective time of a Corporate Transaction, the Board may provide, in its sole discretion, that the holder of such Stock Award
may not exercise such Stock Award but will receive a payment, in such form as may be determined by the Board, equal in value to the excess, if any, of (A) the value of the property the holder of the Stock Award would have received upon the
exercise of the Stock Award (including, at the discretion of the Board, any unvested portion of such Stock Award), over (B) any exercise price payable by such holder in connection with such exercise. 

(d) Change in Control. A Stock Award may be subject to additional acceleration of vesting and exercisability upon or after a
Change in Control as may be provided in the Stock Award Agreement for such Stock Award or as may be provided in any other written agreement between the Company or any Affiliate and the Participant. A Stock Award may vest as to all or any portion of
the shares subject to the Stock Award (i) immediately upon the occurrence of a Change in Control, whether or not such Stock Award is assumed, continued, or substituted by a surviving or acquiring entity in the Change in Control, or (ii) in
the event a Participant’s Continuous Service is terminated, actually or constructively, within a designated period before or after the occurrence of a Change in Control. In the absence of such provisions, no such acceleration shall occur.

  

	10.	TERMINATION OR SUSPENSION OF THE PLAN.

 (a) Plan Term. The Board may suspend or terminate the Plan at any time. Unless terminated sooner, the Plan shall terminate on the day before the tenth (10th) anniversary of the earlier of
(i) the date the Plan is adopted by the Board, or (ii) the date the Plan is approved by the stockholders of the Company. No Stock Awards may be granted under the Plan while the Plan is suspended or after it is terminated. 

(b) No Impairment of Rights. Suspension or termination of the Plan shall not impair rights and obligations under any Stock
Award granted while the Plan is in effect except with the written consent of the affected Participant. 
  

	11.	CHOICE OF LAW.

 The law of
the State of Delaware shall govern all questions concerning the construction, validity and interpretation of this Plan, without regard to that state’s conflict of laws rules. 

 

	12.	DEFINITIONS.

 As used in
the Plan, the following definitions shall apply to the capitalized terms indicated below: 
 (a)
“Affiliate” means, at the time of determination, any “parent” or “subsidiary” of the Company as such terms are defined in Rule 405 of the Securities Act. The Board shall have the authority to
determine the time or times at which “parent” or “subsidiary” status is determined within the foregoing definition. 
 (b) “Board” means the Board of Directors of the Company. 
 (c) “Capitalization Adjustment” means any change that is made in, or other events that occur with respect to, the Common Stock subject to the Plan or subject to any Stock
Award after the Effective Date without the receipt of consideration by the Company (through merger, consolidation, reorganization, recapitalization, reincorporation, stock dividend, dividend in property other than cash, stock split,

  
 16 

 
liquidating dividend, combination of shares, exchange of shares, change in corporate structure or other transaction not involving the receipt of consideration by the Company). Notwithstanding the
foregoing, the conversion of any convertible securities of the Company shall not be treated as a transaction “without the receipt of consideration” by the Company. 
 (d) “Cause” means with respect to a Participant, the occurrence of any of the following events: (i) such Participant’s conviction of, or a plea of nolo contendere
to, a felony; (ii) such Participant’s theft or embezzlement, or attempted theft or embezzlement, of money or property or assets of the Company; (iii) such Participant’s violation of the Company’s drug policy; or
(iv) such Participant’s intentional and willful engagement in misconduct which is materially injurious to the Company. 
 (e) “Change in Control” means the occurrence, in a single transaction or in a series of related transactions, of any one or more of the following events: 

(i) any Exchange Act Person becomes the Owner, directly or indirectly, of securities of the Company
representing more than fifty percent (50%) of the combined voting power of the Company’s then outstanding securities other than by virtue of a merger, consolidation or similar transaction. Notwithstanding the foregoing, a Change in Control
shall not be deemed to occur (A) on account of the acquisition of securities of the Company by an investor, any affiliate thereof or any other Exchange Act Person from the Company in a transaction or series of related transactions the primary
purpose of which is to obtain financing for the Company through the issuance of equity securities or (B) solely because the level of Ownership held by any Exchange Act Person (the “Subject Person” ) exceeds the
designated percentage threshold of the outstanding voting securities as a result of a repurchase or other acquisition of voting securities by the Company reducing the number of shares outstanding, provided that if a Change in Control would occur
(but for the operation of this sentence) as a result of the acquisition of voting securities by the Company, and after such share acquisition, the Subject Person becomes the Owner of any additional voting securities that, assuming the repurchase or
other acquisition had not occurred, increases the percentage of the then outstanding voting securities Owned by the Subject Person over the designated percentage threshold, then a Change in Control shall be deemed to occur; 

(ii) there is consummated a merger, consolidation or similar transaction involving (directly or indirectly)
the Company and, immediately after the consummation of such merger, consolidation or similar transaction, the stockholders of the Company immediately prior thereto do not Own, directly or indirectly, either (A) outstanding voting securities
representing more than fifty percent (50%) of the combined outstanding voting power of the surviving Entity in such merger, consolidation or similar transaction or (B) more than fifty percent (50%) of the combined outstanding voting
power of the parent of the surviving Entity in such merger, consolidation or similar transaction, in each case in substantially the same proportions as their Ownership of the outstanding voting securities of the Company immediately prior to such
transaction; 
 (iii) the stockholders of the Company approve or the Board approves a plan of complete
dissolution or liquidation of the Company, or a complete dissolution or liquidation of the Company shall otherwise occur, except for a liquidation into a parent corporation; 

(iv) there is consummated a sale, lease, exclusive license or other disposition of all or substantially all of
the consolidated assets of the Company and its Subsidiaries, other than a sale, lease, license or other disposition of all or substantially all of the consolidated assets of the Company and its Subsidiaries to an Entity, more than fifty percent
(50%) of the combined voting power of the voting securities of which are Owned by stockholders of the Company in substantially the same proportions relative to each other as their Ownership of the outstanding voting securities of the Company
immediately prior to such sale, lease, license or other disposition; or 

  
 17 

 (v) individuals who, on the date the Plan is adopted by the
Board, are members of the Board (the “Incumbent Board”) cease for any reason to constitute at least a majority of the members of the Board; provided, however, that if the appointment or election (or nomination for
election) of any new Board member was approved or recommended by a majority vote of the members of the Incumbent Board then still in office, such new member shall, for purposes of the Plan, be considered as a member of the Incumbent Board.

 For avoidance of doubt, the term Change in Control shall not include a sale of assets, merger or other transaction effected
exclusively for the purpose of changing the domicile of the Company. 
 Notwithstanding the foregoing or any other provision of
the Plan, the definition of Change in Control (or any analogous term) in an individual written agreement between the Company or any Affiliate and the Participant shall supersede the foregoing definition with respect to Stock Awards subject to such
agreement; provided, however, that if no definition of Change in Control or any analogous term is set forth in such an individual written agreement, the foregoing definition shall apply. 

The Board may, in its sole discretion and without a Participant’s consent, amend the definition of “Change in Control” to
conform to the definition of “Change in Control” under Section 409A of the Code, and the regulations thereunder. 

(f) “Code” means the Internal Revenue Code of 1986, as amended. 

(g) “Committee” means a committee of one (1) or more Directors to whom authority has been delegated
by the Board in accordance with Section 2(c). 
 (h) “Common Stock” means the common stock
of the Company. 
 (i) “Company” means Cempra, Inc., a Delaware corporation. 

(j) “Consultant” means any person, including an advisor, who is (i) engaged by the Company or an
Affiliate to render consulting or advisory services and is compensated for such services, or (ii) serving as a member of the board of directors of an Affiliate and is compensated for such services. However, service solely as a Director, or
payment of a fee for such service, shall not cause a Director to be considered a “Consultant” for purposes of the Plan. 
 (k) “Continuous Service” means that the Participant’s service with the Company or an Affiliate, whether as an Employee, Director or Consultant, is not interrupted or
terminated. A change in the capacity in which the Participant renders service to the Company or an Affiliate as an Employee, Consultant or Director or a change in the entity for which the Participant renders such service, provided that there is no
interruption or termination of the Participant’s service with the Company or an Affiliate, shall not terminate a Participant’s Continuous Service; provided, however, if the Entity for which a Participant is rendering services ceases
to qualify as an “Affiliate,” as determined by the Board in its sole discretion, such Participant’s Continuous Service shall be considered to have terminated on the date such Entity ceases to qualify as an Affiliate. To the extent
permitted by law, the Board or the chief executive officer of the Company, in that party’s sole discretion, may determine whether Continuous Service shall be considered interrupted in the case of: (i) any leave of absence approved by the
Board or the chief executive officer of the Company, including sick leave, military leave or any other personal leave; or (ii) transfers between the Company, an Affiliate, or their successors. Notwithstanding the foregoing, a leave of absence
shall be treated as Continuous Service for purposes of vesting in a Stock Award only to such extent as may be provided in the Company’s leave of absence policy, in the written terms of any

  
 18 

 
leave of absence agreement or policy applicable to the Participant, or as otherwise required by law. 
 (l) “Corporate Transaction” means the occurrence, in a single transaction or in a series of related transactions, of any one or more of the following events: 

(i) a sale or other disposition of all or substantially all, as determined by the Board in its sole
discretion, of the consolidated assets of the Company and its Subsidiaries; 
 (ii) a sale or other
disposition of at least ninety percent (90%) of the outstanding securities of the Company; 

(iii) the consummation of a merger, consolidation or similar transaction following which the Company is not
the surviving corporation; or 
 (iv) the consummation of a merger, consolidation or similar
transaction following which the Company is the surviving corporation but the shares of Common Stock outstanding immediately preceding the merger, consolidation or similar transaction are converted or exchanged by virtue of the merger, consolidation
or similar transaction into other property, whether in the form of securities, cash or otherwise. 
 (m)
“Covered Employee” shall have the meaning provided in Section 162(m)(3) of the Code. 
 (n)
“Director” means a member of the Board. 
 (o) “Disability” means,
with respect to a Participant, the inability of such Participant to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or can be expected to last
for a continuous period of not less than 12 months, as provided in Section 22(e)(3) and 409A(a)(2)(c)(i) of the Code. 
 (p) “Effective Date” means the date the Plan is approved by the stockholders of the Company, as set forth in Section 1(a) hereof. 

(q) “Employee” means any person employed by the Company or an Affiliate. However, service solely as a
Director, or payment of a fee for such services, shall not cause a Director to be considered an “Employee” for purposes of the Plan. 
 (r) “Entity” means a corporation, partnership, limited liability company or other entity. 
 (s) “Exchange Act” means the Securities Exchange Act of 1934, as amended. 
 (t) “Exchange Act Person” means any natural person, Entity or “group” (within the meaning of Section 13(d) or 14(d) of the Exchange Act), except that
“Exchange Act Person” shall not include (i) the Company or any Subsidiary of the Company, (ii) any employee benefit plan of the Company or any Subsidiary of the Company or any trustee or other fiduciary holding securities under
an employee benefit plan of the Company or any Subsidiary of the Company, (iii) an underwriter temporarily holding securities pursuant to an offering of such securities, (iv) an Entity Owned, directly or indirectly, by the stockholders of
the Company in substantially the same proportions as their Ownership of stock of the Company; or (v) any natural person, Entity or “group” (within the meaning of Section 13(d) or 14(d) of the Exchange Act) that, as of the
Effective Date, is the Owner, directly or indirectly, of securities of the Company representing more than fifty percent (50%) of the combined voting power of the Company’s then outstanding securities. 

  
 19 

 (u) “Fair Market Value” means, as of any date, the value of
the Common Stock determined as follows: 
 (i) If the Common Stock is listed on any established stock
exchange or traded on the Nasdaq Global Select Market or the Nasdaq Global Market, the Fair Market Value of a share of Common Stock shall be the closing sales price for such stock as quoted on such exchange (or the exchange or market with the
greatest volume of trading in the Common Stock) on the date of determination, as reported in The Wall Street Journal or such other source as the Board deems reliable. 

(ii) In the absence of such markets for the Common Stock, the Fair Market Value shall be determined by the
Board in good faith and in a manner that complies with Section 409A of the Code. 
 (v) “Incentive Stock
Option” means an Option which qualifies as an “incentive stock option” within the meaning of Section 422 of the Code and the regulations promulgated thereunder. 

(w) “Non-Employee Director” means a Director who either (i) is not a current employee or officer of
the Company or an Affiliate, does not receive compensation, either directly or indirectly, from the Company or an Affiliate for services rendered as a consultant or in any capacity other than as a Director (except for an amount as to which
disclosure would not be required under Item 404(a) of Regulation S-K promulgated pursuant to the Securities Act (“Regulation S-K”)), does not possess an interest in any other transaction for which disclosure
would be required under Item 404(a) of Regulation S-K, and is not engaged in a business relationship for which disclosure would be required pursuant to Item 404(b) of Regulation S-K; or (ii) is otherwise considered a
“non-employee director” for purposes of Rule 16b-3. 
 (x) “Nonstatutory Stock
Option” means an Option that does not qualify as an Incentive Stock Option. 
 (y)
“Officer” means a person who is an officer of the Company within the meaning of Section 16 of the Exchange Act and the rules and regulations promulgated thereunder. 

(z) “Option” means an Incentive Stock Option or a Nonstatutory Stock Option to purchase shares of Common
Stock granted pursuant to the Plan. 
 (aa) “Option Agreement” means a written agreement between
the Company and an Optionholder evidencing the terms and conditions of an Option grant. Each Option Agreement shall be subject to the terms and conditions of the Plan. 
 (bb) “Optionholder” means a person to whom an Option is granted pursuant to the Plan or, if applicable, such other person who holds an outstanding Option. 

(cc) “Other Stock Award” means an award based in whole or in part by reference to the Common Stock which
is granted pursuant to the terms and conditions of Section 6(e). 
 (dd) “Outside Director”
means a Director who either (i) is not a current employee of the Company or an “affiliated corporation” (within the meaning of Treasury Regulations promulgated under Section 162(m) of the Code), is not a former employee of the
Company or an “affiliated corporation” who receives compensation for prior services (other than benefits under a tax-qualified retirement plan) during the taxable year, has not been an officer of the Company or an “affiliated
corporation,” and does not receive remuneration from the Company or an “affiliated corporation,” either directly or indirectly, in any 

  
 20 

 
capacity other than as a Director, or (ii) is otherwise considered an “outside director” for purposes of Section 162(m) of the Code. 

(ee) “Own,” “Owned,” “Owner,”
“Ownership” A person or Entity shall be deemed to “Own,” to have “Owned,” to be the “Owner” of, or to have acquired “Ownership” of securities if such person or Entity, directly or
indirectly, through any contract, arrangement, understanding, relationship or otherwise, has or shares voting power, which includes the power to vote or to direct the voting, with respect to such securities. 

(ff) “Participant” means a person to whom a Stock Award is granted pursuant to the Plan or, if applicable,
such other person who holds an outstanding Stock Award. 
 (gg) “Performance Criteria” means the
one or more criteria that the Board shall select for purposes of establishing the Performance Goals for a Performance Period. The Performance Criteria that shall be used to establish such Performance Goals may be based on any one of, or combination
of, the following: (i) earnings per share; (ii) earnings before interest, taxes and depreciation; (iii) earnings before interest, taxes, depreciation and amortization (EBITDA); (iv) total stockholder return; (v) return on
equity; (vi) return on assets, investment, or capital employed; (vii) operating margin; (viii) gross margin; (ix) operating income; (x) net income (before or after taxes); (xi) net operating income; (xii) net
operating income after tax; (xiii) pre- and after-tax income; (xiv) pre-tax profit; (xv) operating cash flow; (xvi) sales or revenue targets; (xvii) orders and revenue; (xviii) increases in revenue or product revenue;
(xix) expenses and cost reduction goals; (xx) improvement in or attainment of expense levels; (xxi) improvement in or attainment of working capital levels; (xxii) economic value added (or an equivalent metric);
(xxiii) market share; (xxiv) cash flow; (xxv) cash flow per share; (xxvi) share price performance; (xxvii) debt reduction; (xxviii) implementation or completion of projects or processes; (xxix) achievement of
product development or commercialization milestones; (xxx) stockholders’ equity; (xxxi) quality measures; and (xxxii) to the extent that a Stock Award is not intended to comply with Section 162(m) of the Code, other measures
of performance selected by the Board. Partial achievement of the specified criteria may result in the payment or vesting corresponding to the degree of achievement as specified in the Stock Award Agreement. The Board shall, in its sole discretion,
define the manner of calculating the Performance Criteria it selects to use for such Performance Period. 
 (hh)
“Performance Goals” means, for a Performance Period, the one or more goals established by the Board for the Performance Period based upon the satisfaction of the Performance Criteria. Performance Goals may be based on a
Company-wide basis, with respect to one or more business units, divisions, Affiliates, or business segments, and in either absolute terms or relative to the performance of one or more comparable companies or the performance of one or more relevant
indices. At the time of the grant of any Stock Awards, the Board is authorized to determine whether, when calculating the attainment of Performance Goals for a Performance Period: (i) to exclude restructuring and/or other nonrecurring charges;
(ii) to exclude exchange rate effects, as applicable, for non-U.S. dollar denominated net sales and operating earnings; (iii) to exclude the effects of changes to generally accepted accounting standards required by the Financial Accounting
Standards Board; (iv) to exclude the effects of any statutory adjustments to corporate tax rates; and (v) to exclude the effects of any “extraordinary items” as determined under generally accepted accounting principles. In
addition, the Board retains the discretion to reduce or eliminate the compensation or economic benefit due upon attainment of Performance Goals. 
 (ii) “Performance Period” means one or more periods of time, which may be of varying and overlapping duration, as the Committee may select, over which the attainment of one
or more Performance Goals will be measured for the purpose of determining a Participant’s right to and the payment of a Performance Stock Award. 

  
 21 

 (jj) “Performance Stock Award” means an award of shares of
Common Stock which is granted pursuant to the terms and conditions of Section 6(d). 
 (kk)
“Plan” means this Cempra, Inc. 2011 Equity Incentive Plan. 
 (ll) “Prior
Plan” means the Company’s 2004 Stock Plan, as in effect immediately prior to the Effective Date. 
 (mm)
“Restricted Stock Award” means an award of shares of Common Stock which is granted pursuant to the terms and conditions of Section 6(a). 
 (nn) “Restricted Stock Award Agreement” means a written agreement between the Company and a holder of a Restricted Stock Award evidencing the terms and conditions of a
Restricted Stock Award grant. Each Restricted Stock Award Agreement shall be subject to the terms and conditions of the Plan. 

(oo) “Restricted Stock Unit Award” means a right to receive shares of Common Stock which is granted
pursuant to the terms and conditions of Section 6(b). 
 (pp) “Restricted Stock Unit Award
Agreement” means a written agreement between the Company and a holder of a Restricted Stock Unit Award evidencing the terms and conditions of a Restricted Stock Unit Award grant. Each Restricted Stock Unit Award Agreement shall be
subject to the terms and conditions of the Plan. 
 (qq) “Rule 16b-3” means Rule 16b-3
promulgated under the Exchange Act or any successor to Rule 16b-3, as in effect from time to time. 
 (rr)
“Securities Act” means the Securities Act of 1933, as amended. 
 (ss) “Stock
Appreciation Right” means a right to receive the appreciation on Common Stock that is granted pursuant to the terms and conditions of Section 6(c). 
 (tt) “Stock Appreciation Right Agreement” means a written agreement between the Company and a holder of a Stock Appreciation Right evidencing the terms and conditions of a
Stock Appreciation Right grant. Each Stock Appreciation Right Agreement shall be subject to the terms and conditions of the Plan. 
 (uu) “Stock Award” means any Option, Restricted Stock Award, Restricted Stock Unit Award, Stock Appreciation Right, Performance Stock Award, or any Other Stock Award granted
under the Plan. 
 (vv) “Stock Award Agreement” means a written agreement between the Company and
a Participant evidencing the terms and conditions of a Stock Award grant. Each Stock Award Agreement shall be subject to the terms and conditions of the Plan. 
 (ww) “Subsidiary” means, with respect to the Company, (i) any corporation of which more than fifty percent (50%) of the outstanding capital stock having ordinary
voting power to elect a majority of the board of directors of such corporation (irrespective of whether, at the time, stock of any other class or classes of such corporation shall have or might have voting power by reason of the happening of any
contingency) is at the time, directly or indirectly, Owned by the Company, and (ii) any partnership, 

  
 22 

 
limited liability company or other entity in which the Company has a direct or indirect interest (whether in the form of voting or participation in profits or capital contribution) of more than
fifty percent (50%). 
 (xx) “Ten Percent Stockholder” means a person who Owns (or is deemed to
Own pursuant to Section 424(d) of the Code) stock possessing more than ten percent (10%) of the total combined voting power of all classes of stock of the Company or any Affiliate. 

  
 23 

 CEMPRA, INC. 
 2011 EQUITY INCENTIVE PLAN 
 NOTICE OF STOCK OPTION GRANT 

Cempra, Inc. (the “Company”), pursuant to its 2011 Equity Incentive Plan (the “Plan”),
hereby grants to Optionholder an option to purchase the number of shares of the Company’s Common Stock set forth below. This option is subject to all of the terms and conditions as set forth herein and in the Option Agreement, the Plan,
and the Notice of Exercise, all of which are attached hereto and incorporated herein in their entirety. 
  

			
	Optionholder:	  	_____________________________
	Date of Grant	  	__________________
	Grant Number:	  	__________________
	Vesting Commencement Date	  	__________________
	Exercise Price per Share	  	__________________
	Total Number of Shares Granted	  	__________________
	Total Exercise Price	  	__________________
		
	Type of Option:	  	 ̈    Incentive Stock Option
		  	 ̈    Nonstatutory Stock Option
		
	Term/Expiration Date:	  	10 Years/________
		
	Vesting Schedule: 	  	[Insert applicable vesting schedule].
		
	Termination Period:	  	Option may be exercised for up to three (3) months after termination of Continuous Service, except as set out in Section 7 of the Option Agreement (but in no event
later than the Expiration Date); provided that a termination for “Cause” is governed by Section 9 of the Plan, which provides for immediate termination of the Option upon such termination for “Cause.”

 Additional Terms/Acknowledgements: The undersigned Optionholder acknowledges receipt of, and understands and
agrees to, this Option Grant Notice, the Option Agreement, and the Plan. Optionholder also acknowledges receipt of the Cempra, Inc. 2011 Equity Incentive Plan Prospectus. Optionholder further acknowledges that as of the Date of Grant, this
Option Grant Notice, the Option Agreement, and the Plan set forth the entire understanding between Optionholder and the Company regarding the acquisition of stock in the Company and supersede all prior oral and written agreements on that subject
with the exception of options previously granted and delivered to Optionholder. 
  

							
	OPTIONHOLDER:	 		 	CEMPRA, INC.
				
	 	 		 	By:	 	 
	 	 		 	Name:	 	 
	Print Name	 		 	Title:	 	 

 Appendix A 

CEMPRA, INC. 
 2011 EQUITY INCENTIVE PLAN 
 OPTION AGREEMENT 

(INCENTIVE STOCK OPTION OR NONSTATUTORY STOCK OPTION) 
 Pursuant to your Option Grant Notice (“Grant Notice”) and this Option Agreement, Cempra, Inc. (the “Company”) has granted you an option under its 2011
Equity Incentive Plan (the “Plan”) to purchase the number of shares of the Company’s Common Stock indicated in your Grant Notice at the exercise price indicated in your Grant Notice. Defined terms not explicitly
defined in this Option Agreement but defined in the Plan shall have the same definitions as in the Plan. 
 The details of your
option are as follows: 
 1. VESTING. Subject to the limitations contained herein, your option will vest as provided
in your Grant Notice, provided that vesting will cease upon the termination of your Continuous Service. 
 2. NUMBER OF
SHARES AND EXERCISE PRICE. The number of shares of Common Stock subject to your option and your exercise price per share referenced in your Grant Notice may be adjusted from time to time for Capitalization Adjustments. 

3. EXERCISE RESTRICTION FOR NON-EXEMPT EMPLOYEES. In the event that you are an Employee eligible for overtime compensation
under the Fair Labor Standards Act of 1938, as amended (i.e., a “Non-Exempt Employee”), you may not exercise your option until you have completed at least six (6) months of Continuous Service measured from
the Date of Grant specified in your Grant Notice, notwithstanding any other provision of your option. 
 4. METHOD OF
PAYMENT. Payment of the exercise price is due in full upon exercise of all or any part of your option. You may elect to make payment of the exercise price in cash or by check or in one or more of the following manners: 

(a) Provided that at the time of exercise the Common Stock is publicly traded and quoted regularly in The Wall
Street Journal, pursuant to a program developed under Regulation T as promulgated by the Federal Reserve Board that, prior to the issuance of Common Stock, results in either the receipt of cash (or check) by the Company or the receipt of
irrevocable instructions to pay the aggregate exercise price to the Company from the sales proceeds. 
 (b)
Provided that at the time of exercise the Common Stock is publicly traded and quoted regularly in The Wall Street Journal, by delivery to the Company (either by actual delivery or attestation) of already-owned shares of Common Stock that
are owned free and clear of any liens, claims, encumbrances or security interests, and that are valued at Fair Market Value on the date of exercise. “Delivery” for these purposes, in the sole discretion of the Company at the time you
exercise your option, shall include delivery to the Company of your attestation of ownership of such shares of Common Stock in a form approved by the Company. Notwithstanding the foregoing, you may not exercise your option by tender to the Company
of Common Stock to the extent such tender would violate the provisions of any law, regulation or agreement restricting the redemption of the Company’s stock. 

  
 A-1

 (c) Provided that at the time of exercise the Common Stock is
publicly traded and quoted regularly in The Wall Street Journal, and subject to the consent of the Company at the time of exercise, by a “net exercise” arrangement pursuant to which the Company will reduce the number of shares of
Common Stock issued upon exercise of your option by the largest whole number of shares with a Fair Market Value that does not exceed the aggregate exercise price; provided, however, that the Company shall accept a cash or other payment from you to
the extent of any remaining balance of the aggregate exercise price not satisfied by such reduction in the number of whole shares to be issued; provided further, however, that shares of Common Stock will no longer be outstanding under your option
and will not be exercisable thereafter to the extent that (1) shares are used to pay the exercise price pursuant to the “net exercise,” (2) shares are delivered to you as a result of such exercise, and (3) shares are
withheld to satisfy tax withholding obligations. 
 5. WHOLE SHARES. You may exercise your option only for whole
shares of Common Stock. 
 6. SECURITIES LAW COMPLIANCE. Notwithstanding anything to the contrary contained herein,
you may not exercise your option unless the shares of Common Stock issuable upon such exercise are then registered under the Securities Act or, if such shares of Common Stock are not then so registered, the Company has determined that such exercise
and issuance would be exempt from the registration requirements of the Securities Act. The exercise of your option also must comply with other applicable laws and regulations governing your option, and you may not exercise your option if the Company
determines that such exercise would not be in material compliance with such laws and regulations. 
 7. TERM. You
may not exercise your option before the commencement or after the expiration of its term. The term of your option commences on the Date of Grant and expires upon the earliest of the following: 

(a) immediately upon the termination of your Continuous Service for Cause; 

(b) three (3) months after the termination of your Continuous Service for any reason other than Cause, your
Disability or death; provided, however, that (i) if during any part of such three (3) month period your option is not exercisable solely because of the condition set forth in Section 6, your option shall not expire until the
earlier of the Expiration Date or until it shall have been exercisable for an aggregate period of three (3) months after the termination of your Continuous Service and (ii) if (x) you are a Non-Exempt Employee, (y) you terminate
your Continuous Service within six (6) months after the Date of Grant specified in your Grant Notice, and (z) you have vested in a portion of your option at the time of your termination of Continuous Service, your option shall not expire
until the earlier of (A) the later of the date that is seven (7) months after the Date of Grant specified in your Grant Notice or the date that is three (3) months after the termination of your Continuous Service, or (B) the
Expiration Date; 
 (c) twelve (12) months after the termination of your Continuous Service due to
your Disability; 
 (d) twelve (12) months after your death if you die either during your Continuous
Service or within three (3) months after your Continuous Service terminates for any reason other than Cause; 
 (e) the Expiration Date indicated in your Grant Notice; or 

(f) the day before the tenth (10th) anniversary of the Date of Grant. 

  
 A-2

 If your option is an Incentive Stock Option, note that to obtain the federal income tax
advantages associated with an Incentive Stock Option, the Code requires that at all times beginning on the date of grant of your option and ending on the day three (3) months before the date of your option’s exercise, you must be an
employee of the Company or an Affiliate, except in the event of your death or Disability. The Company has provided for extended exercisability of your option under certain circumstances for your benefit but cannot guarantee that your option will
necessarily be treated as an Incentive Stock Option if you continue to provide services to the Company or an Affiliate as a Consultant or Director after your employment terminates or if you otherwise exercise your option more than three
(3) months after the date your employment with the Company or an Affiliate terminates. 
 8. EXERCISE.

(a) You may exercise the vested portion of your option during its term by delivering a Notice of Exercise (in a
form designated by the Company) together with the exercise price to the Secretary of the Company, or to such other person as the Company may designate, during regular business hours, together with such additional documents as the Company may then
require. 
 (b) By exercising your option you agree that, as a condition to any exercise of your option,
the Company may require you to enter into an arrangement providing for the payment by you to the Company of any tax withholding obligation of the Company arising by reason of (i) the exercise of your option, or (ii) the disposition of
shares of Common Stock acquired upon such exercise. 
 (c) If your option is an Incentive Stock Option, by
exercising your option you agree that you will notify the Company in writing within fifteen (15) days after the date of any disposition of any of the shares of the Common Stock issued upon exercise of your option that occurs within two
(2) years after the date of your option grant or within one (1) year after such shares of Common Stock are transferred upon exercise of your option. 
 9. TRANSFERABILITY. Your option is not transferable, except by will or by the laws of descent and distribution, and is exercisable during your life only by you. Notwithstanding the foregoing,
by delivering written notice to the Company, in a form satisfactory to the Company, you may designate a third party who, in the event of your death, shall thereafter be entitled to exercise your option. In addition, you may transfer your option to a
trust if you are considered to be the sole beneficial owner (determined under Section 671 of the Code and applicable state law) while the option is held in the trust, provided that you and the trustee enter into transfer and other agreements
required by the Company. 
 10. OPTION NOT A SERVICE CONTRACT. Your option is not an employment or service contract,
and nothing in your option shall be deemed to create in any way whatsoever any obligation on your part to continue in the employ of the Company or an Affiliate, or of the Company or an Affiliate to continue your employment. In addition, nothing in
your option shall obligate the Company or an Affiliate, their respective stockholders, Boards of Directors, Officers or Employees to continue any relationship that you might have as a Director or Consultant for the Company or an Affiliate.

 11. WITHHOLDING OBLIGATIONS.
 (a) At the time you exercise your option, in whole or in part, or at any time thereafter as requested by the Company, you hereby authorize withholding from payroll and any other amounts payable to
you, and otherwise agree to make adequate provision for (including by means of a “cashless exercise” pursuant to a program developed under Regulation T as promulgated by the Federal Reserve Board to the extent permitted by the
Company), any sums required to satisfy the federal, state, local and 

  
 A-3

 
foreign tax withholding obligations of the Company or an Affiliate, if any, which arise in connection with the exercise of your option. 

(b) Upon your request and subject to approval by the Company, in its sole discretion, and compliance with any
applicable legal conditions or restrictions, the Company may withhold from fully vested shares of Common Stock otherwise issuable to you upon the exercise of your option a number of whole shares of Common Stock having a Fair Market Value, determined
by the Company as of the date of exercise, not in excess of the minimum amount required to be withheld by law (or such lower amount as may be necessary to avoid classification of your option as a liability for financial accounting purposes). Any
adverse consequences to you arising in connection with such share withholding procedure shall be your sole responsibility. 
 (c) You may not exercise your option unless the tax withholding obligations of the Company and/or any Affiliate are satisfied. Accordingly, you may not be able to exercise your option when desired
even though your option is vested, and the Company shall have no obligation to issue a certificate for such shares of Common Stock or release such shares of Common Stock from any escrow provided for herein unless such obligations are satisfied.

 12. NOTICES. Any notices provided for in your option or the Plan shall be given in writing and shall be deemed
effectively given upon receipt or, in the case of notices delivered by mail by the Company to you, five (5) days after deposit in the United States mail, postage prepaid, addressed to you at the last address you provided to the Company.

 13. HEADINGS. The headings of the Sections in this Agreement are inserted for convenience only and shall not
be deemed to constitute a part of this Agreement or to affect the meaning of this Agreement. 
 14. MISCELLANEOUS.

 (a) The rights and obligations of the Company under your option shall be transferable by the
Company to any one or more persons or entities, and all covenants and agreements hereunder shall inure to the benefit of, and be enforceable by, the Company’s successors and assigns. Your rights and obligations under your option may only be
assigned with the prior written consent of the Company. 
 (b) You agree upon request to execute any
further documents or instruments necessary or desirable in the sole determination of the Company to carry out the purposes or intent of your option. 
 (c) You acknowledge and agree that you have reviewed your option in its entirety, have had an opportunity to obtain the advice of counsel prior to executing and accepting your option and fully
understand all provisions of your option. 
 (d) This Agreement shall be subject to all applicable
laws, rules, and regulations, and to such approvals by any governmental agencies or national securities exchanges as may be required. 
 (e) All obligations of the Company under the Plan and this Agreement shall be binding on any successor to the Company, whether the existence of such successor is the result of a direct or
indirect purchase, merger, consolidation, or otherwise, of all or substantially all of the business and/or assets of the Company. 

  
 A-4

 15. GOVERNING PLAN DOCUMENT. Your option is subject to all the provisions
of the Plan, the provisions of which are hereby made a part of your option, and is further subject to all interpretations, amendments, rules and regulations which may from time to time be promulgated and adopted pursuant to the Plan. In
the event of any conflict between the provisions of your option and those of the Plan, the provisions of the Plan shall control. 
 16. CHOICE OF LAW. The interpretation, performance and enforcement of this Agreement shall be governed by the law of the state of Delaware without regard to such state’s conflicts of
laws rules. 
 17. SEVERABILITY. If all or any part of this Agreement or the Plan is declared by any court or
governmental authority to be unlawful or invalid, such unlawfulness or invalidity shall not invalidate any portion of this Agreement or the Plan not declared to be unlawful or invalid. Any Section of this Agreement (or part of such a Section)
so declared to be unlawful or invalid shall, if possible, be construed in a manner which will give effect to the terms of such Section or part of a Section to the fullest extent possible while remaining lawful and valid. 

18. OTHER DOCUMENTS. You hereby acknowledge receipt or the right to receive a document providing the information
required by Rule 428(b)(1) promulgated under the Securities Act.
 19. APPLICATION OF
SECTION 409A. This option is intended to be exempt from the application of Section 409A of the Code (“Section 409A”) pursuant to Treasury Regulation 1.409A-1(b)(6). Notwithstanding the
foregoing or any other provision of this Agreement to the contrary, to the extent that (a) one or more of the payments or benefits received or to be received by you pursuant to this Agreement would constitute deferred compensation subject to
the requirements of Section 409A, and (b) you are a “specified employee” within the meaning of Section 409A, then such payment or benefit (or portion thereof) will be delayed until the earliest date following your
“separation from service” with the Company within the meaning of Section 409A on which the Company can provide such payment or benefit to you without your incurrence of any additional tax or interest pursuant to Section 409A,
with all payments or benefits due thereafter occurring in accordance with the original schedule. 

  
 A-5

 Appendix B 

CEMPRA, INC. 
 2011 EQUITY INCENTIVE PLAN 
 2011 Equity Incentive Plan in the form filed
with this Registration Statement 

 Appendix C 

CEMPRA, INC. 
 2011 EQUITY INCENTIVE PLAN 
 NOTICE OF EXERCISE 

Cempra, Inc.
 Date of Exercise:
                                         
        
 Ladies and Gentlemen: 
 This constitutes notice under my stock option that I elect to purchase the number of shares for the price set forth below. 
  

			
	 Type of option (check one):
	  	 ̈ Incentive                  ̈ Nonstatutory
	 Stock option dated:
	  	___________
	 Number of shares as to which option is exercised:
	  	___________
	 Shares to be issued in name of:
	  	______________________
	 Total exercise price:
	  	$ ___________
	 Cash payment delivered herewith:
	  	$ ___________
	 Value of                  shares of
Cempra, Inc. Common Stock delivered herewith
(1):
	  	$ ___________

 By this exercise, I agree (i) to provide such additional documents as you may require pursuant to
the terms of the Cempra, Inc. 2011 Equity Incentive Plan, (ii) to provide for the payment by me to you (in the manner designated by you) of your withholding obligation, if any, relating to the exercise of this option, and (iii) if this
exercise relates to an incentive stock option, to notify you in writing within fifteen (15) days after the date of any disposition of any of the shares of Common Stock issued upon exercise of this option that occurs within two (2) years
after the date of grant of this option or within one (1) year after such shares of Common Stock are issued upon exercise of this option. 
  

	
	Very truly yours,
	
	  
	 Name:

  
  

	(1)	Shares must meet the public trading requirements set forth in the option. Shares must be valued on the date of exercise in accordance with the terms of the Plan
and the option being exercised, and must be owned free and clear of any liens, claims, encumbrances or security interests. Certificates must be endorsed or accompanied by an executed assignment separate from certificate.Collaborative Research and Development and License Agreement

 Exhibit 10.4 

Portions of this exhibit marked [*] are requested to be treated confidentially. 

COLLABORATIVE RESEARCH AND 
 DEVELOPMENT AND LICENSE AGREEMENT 
 THIS COLLABORATIVE RESEARCH AND
DEVELOPMENT AND LICENSE AGREEMENT (the “Agreement”) is entered into as of March 31, 2006 (the “Effective Date”) by and between OPTIMER PHARMACEUTICALS INC., a Delaware corporation with its
offices located at 10110 Sorrento Valley Road, Suite C, San Diego, California 92121 (“Optimer”), and CEMPRA PHARMACEUTICALS, INC., a Delaware corporation with its offices located at 170 Southport Drive,
Suite 500, Morrisville, NC 27560. Optimer and Cempra may be referred to herein individually as a “Party” or collectively, as the “Parties.” 

RECITALS 

WHEREAS, Optimer is a biopharmaceutical company engaged in the discovery and development of pharmaceutical products using its
proprietary carbohydrate synthesis technology; 
 WHEREAS, Cempra is a biopharmaceutical company engaged in the discovery
and development of novel pharmaceutical products; 
 WHEREAS, Cempra and Optimer desire to enter into a relationship to
identify, develop and commercialize pharmaceutical products comprising novel Macrolide Antibiotics to treat infectious diseases; 
 WHEREAS, Cempra and Optimer entered into a letter agreement dated November 10, 2005 wherein Optimer and Cempra agreed to execute a detailed agreement regarding the synthesis by Optimer of
Macrolide Antibiotics for Cempra; and 
 WHEREAS, Optimer is willing to synthesize Macrolide Antibiotics using its
proprietary carbohydrate synthesis technology, assist Cempra in the development thereof, and is prepared to grant Cempra a license under such technology to allow Cempra to develop and commercialize pharmaceutical products arising from this
relationship; 
 NOW, THEREFORE, in consideration of the foregoing and the covenants and promises contained in this
Agreement, the Parties agree as follows: 
 1. DEFINITIONS 
 1.1 “Affiliate” means a person, corporation, partnership, or other entity that controls, is controlled by or is under common control with a Party. For the purposes of this
Section 1.1, the word “control” (including, with correlative meaning, the terms “controlled by” or “under the common control with”) means the actual power, either directly or indirectly through one or more
intermediaries, to direct the management and policies of such entity, whether by the ownership of at least fifty percent (50%) of the voting stock of such entity, or by contract or otherwise. 

1.2 “ASEAN Countries” means all member nations of the Association of Southeast Asian Nations as of the
Effective Date. 

 1.3 “Cempra Know-How” means any Know-How which is developed or acquired and
Controlled by Cempra or its Affiliates during the term of this Agreement that is necessary and useful for the research, development, manufacture, importation, use, or sale of Cempra Products. 

1.4 “Cempra Patents” means any Patents, other than Optimer Patents, which are Controlled by Cempra or its Affiliates
during the term of this Agreement and that claim the manufacture, importation, use or sale of Macrolide Antibiotics or Cempra Products. 
 1.5 “Cempra Product” means a pharmaceutical product (including but not limited to Combination Products or those comprised of one or more Test Products, Macrolide Antibiotics, or any
analogs or derivatives of either of the foregoing) for which the use, sale, or manufacture thereof would, but for the licenses granted Cempra hereunder, infringe the Optimer Patents in the country in which such product is sold by Cempra, an
Affiliate thereof, or a Third Party sublicensee of either of the foregoing. 
 1.6 “Collaboration” means
all activities performed by or on behalf of Optimer or Cempra in the course of the Research Program with respect to the Development and Commercialization of Test Products and Cempra Products. 

1.7 “Combination Product” means a pharmaceutical product (i) containing (x) in the case of Cempra, an active
pharmaceutical ingredient for which, if included in a pharmaceutical product as the sole active pharmaceutical ingredient the use, sale, or manufacture thereof would, but for the licenses granted Cempra hereunder, infringe the Optimer Patents in the
country in which such product is sold by Cempra, an Affiliate thereof, or a Third Party sublicensee of either of the foregoing, or (y) in the case of Optimer, an active pharmaceutical ingredient which (I) contains a Macrolide Antibiotic,
Test Product, or derivative or analog of either of the foregoing, (II) is a Cempra Product, or (III) whose manufacture, sale, or use is covered in any ASEAN Country by a Valid Claim of any Cempra Patent, Joint Invention Patent, or foreign
counterpart of any Optimer Patent; and (ii) one or more other pharmaceutically active ingredients for which rights are not included in the license granted to (x) Cempra under this Agreement, with respect to Cempra Products, or
(y) Optimer, with respect to Optimer Products. 
 1.8 “Commence” or “Commencement”, when
used to describe a Phase 1 Trial, Phase 2 Trial, Phase 3 Trial, or Phase 4 Trial, means the first dosing of the first patient for such trial. 
 1.9 “Commercialization” means all activities that are undertaken after Regulatory Approval of an NDA for a particular Product and that relate to the commercial marketing and sale of such
Product including advertising, marketing, promotion, distribution, and Phase 4 Trials. 
 1.10 “Confidential
Information” means all Information, and other information and materials, received by either Party from the other Party pursuant to this Agreement that: (i) is designated as confidential at the time of disclosure or promptly thereafter;
(ii) under the circumstances surrounding disclosure should be treated as confidential by the receiving Party, or (iii) by reason of its nature would be treated as confidential by a reasonable receiving party, which would include, without
limitation, trade secrets. 
 1.11 “Control” means, with respect to any intellectual property right, that
a Party owns or has a license to such item or right, and has the ability to grant a license or sublicense in or to such right as set forth herein without violating the terms of any agreement or other arrangement with any Third Party.

 1.12 “Develop” or “Development” means, with respect to a Test Product or Product, engaging in
preclinical and clinical drug development activities, which may include but is not limited to research, pre-clinical, clinical and regulatory activities directed towards obtaining Regulatory Approval of

  
 2 

 
a Product, including but not limited to the performance by Optimer of its obligations and Cempra of its responsibilities under the Research Program. 

1.13 “Development Plan” has the meaning set forth in Section 4.1. 

1.14 “Diligent Efforts” means the carrying out of obligations or tasks in a manner consistent with the efforts a Party
devotes to research, development or marketing of a pharmaceutical product or products of similar market potential, profit potential or strategic value resulting from its own research efforts, taking into account technical and regulatory factors,
target product profiles, product labeling, past performance, costs, economic return, the regulatory environment and competitive market conditions in the therapeutic area, all based on conditions then prevailing, and subject to and in consideration
of, in each case, the resources available to such Party and within such Party’s organization for such efforts. Diligent Efforts requires that a Party, at a minimum, assign responsibility for such obligations to specific employees, sets and
seeks to achieve specific and meaningful objectives for carrying out such obligations, and consistently makes and implements decisions designed and allocates resources reasonably sufficient to advance progress with respect to such objectives.

 1.15 “Fair Market Value” means the fair market value of Cempra capital stock on the date the relevant
milestone is achieved under Section 6.2(a) or (b), as applicable, which shall be determined as follows: 

(a) if the Cempra capital stock to be issued under Section 6.2(a) or (b) is traded on a public securities
exchange or through the Nasdaq National Market, the fair market value thereof shall be deemed to be the average of the closing prices of such security on such exchange over the 30-day period ending three (3) business days prior to the date such
security was received; 
 (b) if the Cempra capital stock to be issued under
Section 6.2(a) or (b) is actively traded over-the-counter, the fair market value thereof shall be deemed to be the average of the closing bid or sale prices (whichever is applicable) over the 30-day period ending three
(3) business days prior to the date such security was received; or 
 (c) If there is no active public market
for any Cempra capital stock issued under Section 6.2(a) or (b), the fair market value thereof shall be as determined in good faith by Cempra’s Board of Directors based on a reasonable consideration of all relevant factors.

 1.16 “FDA” means the United States Food and Drug Administration, or any successor federal
agency thereto. 
 1.17 “Field” means all human and animal diagnostic and therapeutic uses. 

1.18 “First Commercial Sale” means the first sale of commercial quantities of any Product sold to a Third Party by a
Party, its Affiliate, or a sublicensee of either of the foregoing in any country after, if and as reasonably necessary or applicable, receipt of Regulatory Approval for such Product in such country. Sales for test marketing, sampling and promotional
uses or clinical trial or research purposes or compassionate uses will not be considered to constitute a First Commercial Sale 
 1.19 “FTE” means the equivalent of one person working full time for one 12-month period in a research, development, commercialization, regulatory or other relevant capacity, approximating
1800 hours per year. In the interests of clarity, though, a single individual who works more than 1800 hours in a single year shall be treated as one FTE regardless of the number of hours worked. 

  
 3 

 1.20 “Good Clinical Practices” or “GCP” means current Good
Clinical Practices as specified in the United States Code of Federal Regulations, at the time of testing, and all FDA and ICH guidelines, including the ICH Consolidated Guidelines on Good Clinical Practices. 

1.21 “Good Laboratory Practices” or “GLP” means current Good Laboratory Practices as specified in the
United States Code of Federal Regulations at 21 CFR § 58 at the time of testing and all applicable ICH guidelines. 
 1.22 “Good Manufacturing Practices” or “GMP” means current Good Manufacturing Practices and standards as provided for (and as amended from time to time) in European
Community Directive 91/356/EEC (Principles and Guidelines of Good Manufacturing Practice for Medicinal Products) and in the Current Good Manufacturing Practice Regulations of the United States Code of Federal Regulations Title 21 (21 CFR
§§ 210-211) in relation to the production of pharmaceutical intermediates and active pharmaceutical ingredients, as interpreted by ICH Harmonized Tripartite Guideline, Good Manufacturing Practice Guide for Active Pharmaceutical
Ingredients, and subject to any arrangements, additions or clarifications agreed from time to time between the Parties. 

1.23 “Governmental Authority” means any court, agency, department or other instrumentality of any foreign, federal,
state, county, city or other political subdivision. 
 1.24 “Human Clinical Trial” means any Phase 1
Trial, Phase 2 Trial, Phase 3 Trial or Phase 4 Trial the subject of which includes a Test Product or Product. 
 1.25 “IND” means an Investigational New Drug Application filed with the FDA or the equivalent application or filing filed with any equivalent agency or government authority outside
of the United States (including any supra-national agency such as in the European Union) necessary to Commence human clinical trials in such jurisdiction, and including all regulations at 21 CFR § 312 et. esq., and equivalent
foreign regulations. 
 1.26 “Information” means information, results and data of any type whatsoever,
including without limitation, databases, inventions, practices, methods, techniques, specifications, formulations, formulae, knowledge, know-how, skill, experience, test data including pharmacological, biological, chemical, biochemical,
toxicological and clinical test data, analytical and quality control data, stability data, studies and procedures, and patent and other legal information or descriptions. 
 1.27 “Invention” means any discovery, invention, improvement, concept or idea, whether or not patentable, conceived or reduced to in the course of the activities conducted pursuant to
this Agreement, together with all intellectual property rights relating thereto. Inventions may include, but not be limited to, processes, compounds, compositions, or methods. 

1.28 “Know-How” means any non-public, proprietary Information and other data, instructions, processes, methods,
formulae, techniques, compositions, materials, expert opinions and information, including without limitation, biological, chemical, pharmacological, toxicological, pharmaceutical, physical and analytical, clinical, safety, manufacturing and quality
control data and information. Know-How does not include any rights under Patents. 
 1.29 “Letter
Agreement” means the letter agreement between Optimer and Cempra dated November 11, 2005. 

  
 4 

 1.30 “Macrolide Antibiotics” means any macrolide or ketolide, including but
not limited to any (i) [*] compound that incorporates, is based on, or is described in, or the synthesis of which is in whole or part based on or described in, the Optimer Technology, including but not limited to those synthesized by
Optimer under this Agreement or the Letter Agreement, (ii) [*] (including but not limited to [*]), and (iii) any derivatives or analogs of any of the foregoing. For avoidance of doubt, the parties expressly agree that Macrolide Antibiotics
shall not mean any 18-membered-lactone-ring-based compound (e.g., Optimer’s OPT-80). 
 1.31 “NDA”
means a New Drug Application filed with the FDA or the equivalent application or filing filed with any equivalent Governmental Authority outside of the United States necessary for approval of a drug in such jurisdiction. 

1.32 “Net Sales” means 
 (a) with respect to a Product (subject to subsections (b) and (c) below), the amount received by a Party or its Affiliate or a Third Party sublicensee for sales of such Product
to Third Parties, excluding reasonable sales returns, allowances and rebates actually paid, granted or accrued, including, without limitation, trade, quantity and cash discounts and any other reasonable adjustments actually allowed, including, but
not limited to, those granted on account of price adjustments (including retroactive price adjustments), billing errors, rejected goods, damaged or defective goods, recalls, returns, rebates, chargeback rebates, reimbursements or similar payments
granted or given to wholesalers or other distributors, buying groups, health care insurance carriers or other institutions, pharmacy benefit management companies, health maintenance organizations or other health care organizations, or any
governmental or regulatory authority or agency (including their purchasers and/or reimbursers), adjustments arising from consumer discount programs, customs or excise duties, tariffs, sales tax, consumption tax, value added tax, and other taxes
(except income taxes) or duties relating to sales, and similar payments respect to the United States government, any state government, any local government, or any foreign government, or to any governmental or regulatory authority in respect of
sales, and freight, handling, and insurance; and 
 (b) in the case of Combination Products, 

(i) if a Party and/or its Affiliate and/or any Third Party sublicensee of either of the foregoing separately sells in such country
during such year when it sells such Combination Product both (1) one or more Products containing solely one particular active pharmaceutical ingredient and (2) products containing other pharmaceutically active ingredient(s) that are
also contained in such Combination Product, the Net Sales attributable to such Combination Product during such year shall be calculated by multiplying actual Net Sales of such Combination Product by the fraction A/(A+B) where: A is such Party’s
(or its Affiliate’s or Third Party sublicensee’s, as applicable) average Net Sales price per daily dose during such year for each Product(s) in such Combination Product in such country and B is the sum of the average of such
Party’s (or its Affiliate’s or Third Party sublicensee’s, as applicable) net sales price per daily dose during such year in such country, for each product(s) containing the other pharmaceutically active ingredient(s) in such
Combination Product (other than the Product); 
 (ii) if a Party and/or its Affiliate and/or any Third Party sublicensee of
either of the foregoing separately sells, in such country during such year when it sells such Combination Product, one or more Products containing solely one particular active pharmaceutical ingredient entity but do not separately sell, in such
country, other products containing the other active ingredient(s) that are also contained in such Combination Product, the Net Sales attributable to such Combination Product 

 
  

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
 5 

 during such year shall be calculated by multiplying the Net Sales of such Combination Product by the
fraction A/C where: A is the applicable Party’s (or its Affiliate’s or Third Party sublicensee’s, as applicable) average Net Sales price per daily dose during such year for each Product in such Combination Product in such country, and
C is such Party’s (or its Affiliate’s or Third Party sublicensee’s, as applicable) average Net Sales price per daily dose during such year for the Combination Product in such country; and 

(iii) if a Party and/or its Affiliates and/or their Third Party sublicensees do not separately in such country during such year sell
products containing each active pharmaceutical ingredient in the Combination Product, then the Net Sales attributable to such Combination Product may, following mutual agreement of the Parties concerning the applicable fair market values, be
determined by multiplying the Net Sales of such Combination Product by the fraction D/(D+E) where D is the fair market value of the portion of the Combination Product that contains the Product with a single active pharmaceutical ingredient and E is
the fair market value of the portion of the Combination Product containing the other pharmaceutically active ingredient(s) and the delivery device included in such Combination Product, as such fair market values are reasonably determined by
mutual agreement of the Parties in good faith. In the event that the Parties are unable to mutually agree upon appropriate fair market values for D and E as set forth herein, such matter may be referred to arbitration as set forth in
Section 12.3 below. 
 (c) In the case of discounts on “bundles” of separate products or services which
include Products, a Party may with notice to the other Party discount the bona fide list price of a Product by the average percentage discount of all products of such Party (the “Selling Party”) and/or its Affiliates or Third Party
sublicensees in a particular “bundle”, calculated as follows: 
  

							
	 Average percentage
	  				  	
	 discount on a
	  	 	=	  	  	1 -(X/Y) × 100
	 particular “bundle”
	  				  	

 where X equals the total discounted price of a particular “bundle” of products, and Y equals the sum of the
undiscounted bona fide list prices of each unit of every product in such “bundle”. The Selling Party shall provide the other Party documentation reasonably supporting such average discount with respect to each “bundle.” If a
Product in a “bundle” is not sold separately, and no bona fide list price exists for such Product, the parties shall negotiate in good faith a reasonable imputed list price for such Product and Net Sales with respect thereto shall be based
on such imputed list price; provided, however, that in the event that the Parties are unable to mutually agree upon appropriate imputed list price as set forth herein, then such matter may be referred to arbitration as set forth in Section 12.3
below. 
 1.33 “Optimer Improvements” means any Other Sole Inventions of Optimer and, to the extent owned by
Optimer, Other Joint Inventions that, in either case, constitute improvements, enhancements, or modifications of any Macrolide Antibiotics, Cempra Products, or other technology claimed in the Optimer Patents listed on Schedule 1.30, or
which would be useful or necessary in the manufacture, use, or sale of Cempra Products. 
 1.34 “Optimer
Know-How” means all Know-How Controlled by Optimer or its Affiliates as of the Effective Date, or which is developed or acquired by and Controlled by Optimer or its Affiliates during the term of this Agreement, including but not limited to
any Know-How related to Optimer Improvements, that is necessary or useful for the research, development, manufacture, importation, use or sale of the Macrolide Antibiotics, Test Products or Cempra Products. 

  
 6 

 1.35 “Optimer Patents” means any Patents Controlled by Optimer or its
Affiliates as of the Effective Date or which are developed and Controlled, or licensed to and Controlled, by Optimer or its Affiliates during the term of this Agreement, that are necessary or useful for the research, development, manufacture,
importation, use or sale of Macrolide Antibiotics, Test Products, or Cempra Products, including without limitation, the Patents listed on Schedule 1.35 and any Patents (or, with respect to Patents jointly owned by the Parties,
Optimer’s rights to any such Patents) claiming any Optimer Improvements. 
 1.36 “Optimer Product” means
any product (including but not limited to Combination Products) developed and/or commercialized by Optimer in any ASEAN Country that (i) contains a Macrolide Antibiotic, Test Product, or derivative or analog of either of the foregoing,
(ii) is a Cempra Product, or (iii) whose manufacture, sale, or use is covered in any ASEAN Country by a Valid Claim of any Cempra Patent, Joint Invention Patent, or foreign counterpart of any Optimer Patent. For avoidance of doubt, the
parties expressly agree that, for purposes of this Agreement (including, but not limited to, Optimer’s royalty payment obligation set forth in Article 6), Optimer Products shall not include any product which incorporates an
18-membered-lactone-ring-based compound as an active pharmaceutical ingredient (e.g., Optimer’s OPT-80) unless such product incorporates an additional active pharmaceutical ingredient which itself (or the mechanism of action of which)
independently renders such product an Optimer Product pursuant to the foregoing definition. 
 1.37 “Optimer
Technology” means Optimer Patents and Optimer Know-How. 
 1.38 “Patent” means: (a) an issued
unexpired United States or foreign patent (including inventor’s certificate) that has not been held invalid or unenforceable by a court of competent jurisdiction from which no appeal can be taken or has been taken within the required time
period, including without limitation any substitution, extension, registration, confirmation, reissue, re-examination, renewal or any like filing thereof; or (b) any pending United States or foreign patent application, including without
limitation any continuation, division or continuation-in-part thereof and any provisional application. 
 1.39
“Phase 1 Trial” means a clinical trial that generally provides for the first introduction into humans of a Product with the primary purpose of determining safety, metabolism and pharmacokinetic properties and clinical pharmacology
of the Product, and generally consistent with 21 CFR § 312.21(a). 
 1.40 “Phase 2 Trial”
means a clinical trial of a Product on patients, including possibly pharmacokinetic studies, the principal purpose of which is to make a preliminary determination that such Product is safe for its intended use and to obtain sufficient information
about such Product’s efficacy to permit the design of further clinical trials, and generally consistent with 21 CFR § 312.21(b). 
 1.41 “Phase 3 Trial” means a clinical trial that provides for a pivotal human clinical trial of a Product, which trial is designed to: (a) establish that a Product is safe and
efficacious for its intended use; (b) define warnings, precautions and adverse reactions that are associated with the Product in the dosage range to be prescribed; (c) support Regulatory Approval of such Product; and (d) generally
consistent with 21 CFR § 312.21(c). 
 1.42 “Phase 4 Trial” means clinical trial of a
Product Commenced in a particular country after Regulatory Approval for such Product in such country in order to support commercialization of the Product. 
 1.43 “Product” means an Optimer Product or Cempra Product, as appropriate. 

  
 7 

 1.44 “Regulatory Approval” means any and all approvals (including
supplements, amendments, pre- and post-approvals, pricing and reimbursement approvals), licenses, registrations or authorizations of any national, supra-national (e.g., the European Commission or the Council of the European Union), regional,
state or local regulatory agency, department, bureau, commission, council or other governmental entity, that are necessary for the manufacture, distribution, use or, in the Commercializing Party’s reasonable judgment, sale of a Product in a
regulatory jurisdiction. 
 1.45 “Regulatory Authority” means any Governmental Authority with responsibility
for granting any licenses or approvals necessary for the marketing and sale of pharmaceutical products including, without limitation, the FDA and any drug regulatory authority of countries of the European Union, and Japan, and where applicable any
ethics committee or any equivalent review board. 
 1.46 “Regulatory Filing” means the NDA, biologic
license application (“BLA”), IND, or any foreign counterparts thereof and any other filings required by regulatory authorities relating to the study, manufacture or commercialization of any Product. 

1.47 “Research Program” means the activities conducted by Optimer and Cempra pursuant to the obligations and
responsibilities set forth in a Work Plan and Budget established by the Parties pursuant to this Agreement. 
 1.48
“Research Term” means the period commencing on the Effective Date and continuing until the earlier of (i) completion by Optimer of the tasks assigned to Optimer in the Work Plan and Budget or (ii) the second anniversary of
the Effective Date, subject to any extensions thereof agreed to by the Parties in writing. 
 1.49 “Royalty
Term” means, on a country-by-country and Product-by-Product basis: 
 (a) For Cempra Products, the period
commencing on the First Commercial Sale thereof in a particular country and continuing until the later of (a) the last to expire Valid Claim of an Optimer Patent covering the manufacture, use or sale of such Cempra Product in such country or
(b) ten (10) years following the First Commercial Sale of such Cempra Product in such country; and 
 (b)
For Optimer Products, the period commencing on the First Commercial Sale thereof in a particular country and continuing until the later of (a) the last to expire Valid Claim of a Cempra Patent covering the manufacture, use or sale of such
Optimer Product in such country or (b) ten (10) years following the First Commercial Sale of such Optimer Product in such country. 
 1.50 “Sublicensing Revenue” means net revenue received from Third Party sublicensees, other than royalties or other payments calculated on the basis of sales of Cempra Products, directly
and solely as consideration for Cempra’s or its Affiliates’ sublicensing to Third Parties (other than Cempra Affiliates) of the rights to Optimer Patents licensed to Cempra and its Affiliates under this Agreement, including but not limited
to upfront and milestone payments, but excluding (i) [*]. 
 1.51 “Term” has the meaning assigned
to it in Section 9.1. 
 1.52 “Territory” means worldwide, excluding ASEAN Countries. 

1.53 “Test Product” means a Macrolide Antibiotic or derivative or analog thereof that has been designated by Cempra to
be the subject of Development pursuant to Section 3.4. 
  

 

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
 8 

 1.54 “Third Party” means any entity other than (a) Optimer,
(b) Cempra or (c) an Affiliate of either of them. 
 1.55 “Valid Claim” means a claim of any
pending patent application or any issued, unexpired United States or granted foreign patent within any Patent that has not been dedicated to the public, disclaimed, abandoned or held invalid or unenforceable by a court or other body of
competent jurisdiction from which no further appeal can be taken, and that has not been explicitly disclaimed, or admitted by the Party Controlling such Patent in writing to be invalid or unenforceable or of a scope not covering Products through
reissue, disclaimer or otherwise. 
 1.56 “Work Plan and Budget” has the meaning set forth in
Section 3.1. 
 1A. JOINT STEERING COMMITTEE 
 1A.1 Joint Steering Committee. Promptly after the Effective Date, the Parties shall establish a “Joint Steering Committee” as described in this Section 1A. The Joint Steering
Committee shall exist during the Research Term. The Joint Steering Committee shall, subject to applicable provisions of this Agreement concerning the Research Program, Work Plan, and Budget, (i) develop, review, approve, and establish all
aspects of the Work Plan and Budget and, once the initial Work Plan and Budget have been established, (ii) monitor and oversee the Parties’ progress thereunder, advise the Parties with respect thereto, and develop, review, and approve any
changes or amendments to the Work Plan and Budget, such changes and amendments to be effective upon approval thereof by the Joint Steering Committee and agreement by (i) Optimer with respect to obligations of Optimer (such agreement not to be
unreasonably withheld) or (ii) Cempra with respect to responsibilities of Cempra, provided that, notwithstanding the foregoing, the Joint Steering Committee shall have no authority to amend the body of this Agreement. Each party shall indicate
in writing within five (5) business days of approval by the Joint Steering Committee whether or not it agrees to its proposed obligations or responsibilities, and, if not agreeing to its proposed obligations or responsibilities, provide its
reasonable objections thereto. In the absence of such written notice within such five (5) business day period, a party shall be deemed to have rejected its proposed obligations or responsibilities, and, in the event Optimer rejects its proposed
obligations or responsibilities (whether by written notice or the absence thereof), Cempra shall be free to pursue alternative solutions therefor. Notwithstanding anything to the contrary in this Agreement, the Joint Steering Committee shall have no
rights or responsibilities, and Cempra shall have no obligations with respect to the Joint Steering Committee, following the Research Term. 
 1A.2 Membership. The Joint Steering Committee will be comprised of an equal number of representatives from each Party. The exact number of such representatives shall be as agreed upon by the
Parties, but no event shall such number be less than two (2) nor more than five (5) for each Party. Each Party shall provide the other with a list of its initial members of the Joint Steering Committee promptly after the Effective Date.
Each Party may replace any or all of its representatives on the Joint Steering Committee at any time upon written notice to the other Party. Any member of the Joint Steering Committee may designate a substitute to attend and perform the functions of
that member at any meeting of the Joint Steering Committee. Each Party may, in its reasonable discretion, invite non-member representatives of such Party to attend meetings of the Joint Steering Committee. 

1A.3 Meetings. During the Research Term, the Joint Steering Committee shall meet at least twice per calendar year, or more
frequently as the Parties deem appropriate, on such dates, and at such places and times, as provided herein or as the Parties shall agree, provided, however, that (i) the first meeting shall be held within 30 days of the Effective Date and
(ii) the Joint Steering Committee and the Parties shall use best efforts to draft, review, and approve the initial Work Plan and Budget as soon as reasonably practicable following the Effective Date. Meetings of the Joint Steering Committee
shall 

  
 9 

 
alternate between the offices of the Parties or their respective Affiliates, or such other place as the Parties may agree. The members of the Joint Steering Committee also may convene or be
polled or consulted from time to time by means of telecommunications, video conferences, electronic mail or correspondence, as deemed necessary or appropriate, provided that the Parties hold at least one face-to-face meeting each year. Each Party
shall bear all costs and expenses relating to its members’ attendance at meetings of the Joint Steering Committee. 

1A.4 Decision-Making. The Joint Steering Committee shall use good faith efforts to operate and make decisions by consensus,
provided that in the event the Joint Steering Committee is unable to reach consensus regarding any matter before the Joint Steering Committee within a reasonable period of time not to exceed ten (10) business days, Cempra shall have the
tie-breaking vote to resolve such deadlock and determine the Joint Steering Committee’s final decision regarding such matter, including but not limited to approval of any Work Plan and Budget, or any changes thereto, consistent with the
parameters described below, provided that no Work Plan or Budget shall be effective without the written agreement of (i) Optimer with respect to any obligations of Optimer thereunder (such agreement not to be unreasonably withheld) and
(ii) Cempra with respect to any responsibilities of Cempra thereunder (such agreement not to be unreasonably withheld). Each party shall indicate in writing within five (5) business days of approval by the Joint Steering Committee whether
or not it agrees to its proposed obligations or responsibilities, and, if not agreeing to its proposed obligations or responsibilities, provide its reasonable objections thereto. In the absence of such written notice within such five
(5) business day period, a party shall be deemed to have rejected its proposed obligations or responsibilities, and, in the event Optimer rejects its proposed obligations or responsibilities (whether by written notice or the absence thereof),
Cempra shall be free to pursue alternative solutions therefor. 
 2. MANAGEMENT OF THE RESEARCH PROGRAM 

2.1 General. The general purpose of the Collaboration described in Sections 2 and 3 of this Agreement is to
synthesize, develop and commercialize Macrolide Antibiotics for sale as Cempra Products. If and as determined by the Joint Steering Committee, Optimer shall synthesize Macrolide Antibiotics and conduct preliminary research and biological testing on
such Macrolide Antibiotics according to a Work Plan and Budget that has been developed and approved by the Joint Steering Committee and agreed upon by Optimer and Cempra (such agreement not to be unreasonably withheld). Each party shall indicate in
writing within five (5) business days of approval by the Joint Steering Committee whether or not it agrees to the Work Plan or Budget approved by the Joint Steering Committee and, if not agreeing thereto, provide its reasonable objections
thereto. In the absence of such written notice within such five (5) business day period, a party shall be deemed to have agreed to such Work Plan and Budget. Cempra shall, as determined by the Joint Steering Committee, conduct (or have
conducted by Third Parties) preclinical and animal testing on such Macrolide Antibiotics synthesized by Optimer. Based on the results of such research, the Joint Steering Committee may designate certain Macrolide Antibiotics as Test Products for
preclinical testing and further development by Cempra. Cempra shall be solely responsible, at its expense, for animal testing, preclinical and clinical development of such Test Products, including as may be provided for in a Work Plan and Budget
approved by the Joint Steering Committee and agreed upon (i) by Optimer with respect to Optimer’s obligations thereunder (such agreement not to be unreasonably withheld) and (ii) Cempra with respect to Cempra responsibilities
thereunder. Each party shall indicate in writing within five (5) business days of approval by the Joint Steering Committee whether or not it agrees to its proposed obligations or responsibilities, and, if not agreeing to such obligations or
responsibilities, provide its reasonable objections thereto. In the absence of such written notice within such five (5) business day period, a party shall be deemed to have rejected its proposed obligations or responsibilities, and in the event
Optimer rejects its proposed obligations or responsibilities (whether by written notice or the absence thereof), Cempra shall be free to pursue alternative solutions therefor. For so long as Cempra retains its license hereunder, and except as
provided 

  
 10 

 
for performance by Optimer under any Work Plan and Budget, Cempra shall be responsible for the research, Development, manufacturing, marketing and Commercialization of Cempra Products, subject
only to the terms and conditions of this Agreement, including without limitation the payments owed to Optimer for such Cempra Products as set forth in Article 6. 
 2.2 Information Exchange. During the Research Term, Optimer and Cempra shall keep the Joint Steering Committee fully and regularly informed of their activities (and the activities of
their Affiliates and/or sublicensees) in connection with their conduct of the Research Program and the Development and Commercialization of Test Products and Cempra Products, and shall diligently respond to any other reasonable requests by the Joint
Steering Committee or the other Party for information. Each Party will provide the Joint Steering Committee (during the Research Term) and the other Party (during the entire term of this Agreement) with formal written progress reports of its
activities under this Agreement, no less than twice per year. 
 2.3 Independence. Subject to the terms of this
Agreement and any applicable Work Order and Budget, the activities and resources of each Party shall be managed by such Party, acting independently and in its individual capacity. The relationship between Optimer and Cempra is that of independent
contractors and neither Party shall have the power to bind or obligate the other Party in any manner, other than as is expressly set forth in this Agreement. 
 3. CONDUCT OF THE RESEARCH PROGRAM 
 3.1 Work Plan and
Budget. The Research Program shall be carried out by Optimer and Cempra according to a written work plan setting forth the obligations of Optimer and responsibilities of Cempra (the “Work Plan”) and budget providing for
Cempra’s funding of Optimer’s obligations thereunder (the “Budget”). The Work Plan shall set forth in reasonable detail the obligations of Optimer and responsibilities of Cempra with respect to the Research Program,
including the identity and number of Macrolide Antibiotics that Optimer shall endeavor to synthesize and formulate for animal testing, and shall include the desired quantities of such Macrolide Antibiotics, timeframe for delivery, technical
specifications (the “Specifications”), and the Budget shall set forth the budget for such synthesis and formulation work by Optimer. The Joint Steering Committee shall develop an initial Work Plan and Budget and shall submit such
plan to Optimer and Cempra for review and approval, such approval not to be unreasonably withheld, within thirty (30) days following the execution of this Agreement. In the absence of a party’s written approval of or reasonable objection
to the Work Plan and Budget within five (5) business days of its submission to the parties by the Joint Steering Committee, a party shall be deemed to have agreed to such Work Plan and Budget. The Work Plan and Budget may be amended from time
to time by the Joint Steering Committee during the Research Term, based upon the data obtained in the Research Program or from Cempra’s independent activities, provided such amendments do not violate or contradict any provision of this
Agreement. In the event of an inconsistency or disagreement between the Work Plan and Budget and this Agreement, the terms of this Agreement shall prevail. 
 3.2 Work Performed to Date. The Parties acknowledge that initial research and Macrolide Antibiotics synthesis activities have been conducted by the Parties pursuant to the Letter Agreement
(the “Initial Research”). All Initial Research, including any Macrolide Antibiotics, Information, inventions, know-how, data, information, or other intellectual property rights created pursuant to the Initial Research, is deemed
included within the scope of this Agreement. No amounts shall be due Optimer by Cempra for the conduct of the Initial Research. 

3.3 Synthesis of Macrolide Antibiotics and Biological Testing. The Joint Steering Committee shall, during the Research Term,
determine the Macrolide Antibiotics designated for synthesis and Development under this Agreement, and Optimer shall provide its advice and comment with respect 

  
 11 

 
thereto. The Joint Steering Committee shall determine which Macrolide Antibiotics will be the subject of synthesis and Development as part of Optimer’s performance under the Research
Program, and Optimer shall provide its advice and comment with respect thereto, provided that Optimer shall have no obligation to perform such synthesis and Development without its consent (such consent not to be unreasonably withheld). Optimer
shall indicate in writing within five (5) business days of approval by the Joint Steering Committee whether or not it consents, and, if not consenting, provide its reasonable objections to such obligations. In the absence of such written
consent or reasonable objection within such five (5) business day period, Optimer shall be deemed to have rejected such obligations and Cempra shall be free to seek alternative solutions therefor. The Joint Steering Committee shall, during the
Research Term, designate the initial number of Macrolide Antibiotics for synthesis under this Agreement, provided Optimer shall provide its advice and comment with respect thereto. Optimer shall, if and as included in the Work Plan and Budget, use
Diligent Efforts to synthesize Macrolide Antibiotics that have been designated by the Joint Steering Committee for synthesis, to conduct biological testing on such Macrolide Antibiotics, and to provide such Macrolide Antibiotics in reasonable
quantities to Cempra as determined by the Joint Steering Committee. If and as included in the Work Plan and Budget, Optimer shall use Diligent Efforts to synthesize and conduct biological testing with respect to each Macrolide Antibiotic according
to applicable Specifications for such Macrolide Antibiotics, and to produce and provide to Cempra a sufficient quantity of each Macrolide Antibiotic to allow Cempra to conduct further Development of such Macrolide Antibiotics. Optimer shall use
Diligent Efforts to provide additional quantities of each Macrolide Antibiotics to Cempra at Cempra’s reasonable request on an as needed basis. The reasonable, documented direct expense of manufacturing additional quantities of Macrolide
Antibiotics will be paid for by Cempra as set forth in the Work Plan and Budget. 
 3.4 Preclinical Testing and Human
Clinical Testing. Cempra may perform, in its sole discretion and at its own expense, after, during the Research Term, providing reasonable opportunity for advice and comment by the Joint Steering Committee, preclinical testing on Macrolide
Antibiotics that have been synthesized by Optimer or any other Cempra Products of Cempra’s choosing. Based on the results of any such preclinical testing, the Joint Steering Committee may, subject to the advice and comment of Cempra and
Optimer, determine whether additional Macrolide Antibiotics should be synthesized or developed by Optimer for preclinical testing, or whether any existing Macrolide Antibiotics should be reformulated by Optimer (or a Third Party) for further
testing. The Joint Steering Committee may, subject to Optimer’s and Cempra’s approval (such approval not to be unreasonably withheld), amend or revise the applicable Work Plan and Budget accordingly to allow for such additional synthesis
or reformulation activities. Each party shall indicate in writing within five (5) business days of approval by the Joint Steering Committee whether or not it approves of such amendment or revision, as applicable, and, if not approving thereof,
provide its reasonable objections thereto. In the absence of such a written response from a particular party within such five (5) business day period, a party shall be deemed to have rejected such amendment or revision to the extent it proposes
additional obligations or responsibilities for the objecting party, and, in the event Optimer rejects its proposed obligations or responsibilities (whether by written notice or the absence thereof), Cempra shall be free to pursue independent
solutions with respect to the subject matter of the rejected amendment or revision. Cempra shall, after, during the Research Term, providing reasonable opportunity for advice and comment by the Joint Steering Committee, have the right to designate
one or more of such Macrolide Antibiotics as Test Products for human clinical testing. In the event that Cempra enrolls a patient for human clinical testing of any Macrolide Antibiotics prior to formal designation of such Macrolide Antibiotics as a
Test Product, such Macrolide Antibiotics shall be deemed to have been designated as a Test Product upon enrollment of the first such patient. If a Test Product does not achieve desirable results during Phase 1 Trials, then, if and as requested
by the Joint Steering Committee, subject to Optimer’s consent (such consent not to be unreasonably withheld), Optimer shall use Diligent Efforts to reformulate such Test Product according to specifications established by the Joint Steering
Committee. Any such reformulation activities shall be reflected in a revised Work Plan and Budget to be developed and approved by the Joint Steering 

  
 12 

 
Committee, negotiated in good faith, and agreed upon by the Parties (such agreement not to be unreasonably withheld), and the reasonable, documented, direct costs incurred by Optimer for such
reformulation and related additional testing of a Test Product by Optimer shall be borne by Cempra pursuant to such Budget. Each party shall indicate in writing within five (5) business days of approval by the Joint Steering Committee whether
or not it agrees to such revised Work Plan and Budget, and, if not agreeing to its proposed additional obligations or responsibilities contained therein, provide its reasonable objections thereto. In the absence of providing such written notice
within such five (5) business day period, a party shall be deemed to have rejected its proposed obligations or responsibilities, and, in the event Optimer rejects its proposed obligations or responsibilities (whether by written notice or the
absence thereof), Cempra shall be free to seek alternative solutions therefor. In the event that Cempra enrolls a patient in a Phase 2 Trial or in a Phase 3 Trial, or obtains Regulatory Approval, for any Macrolide Antibiotics or Test
Product prior to formal designation of such Macrolide Antibiotics or Test Product as a Cempra Product, such Macrolide Antibiotics or Test Product shall be deemed to have been designated as a Cempra Product upon the first such event to occur with
respect to such Macrolide Antibiotics or Test Product. 
 3.5 Pre-Clinical and Clinical Supply. As may be
provided in any Work Plan and Budget established by the Joint Steering Committee and agreed upon by Optimer, Optimer shall use Diligent Efforts in accordance with such Work Plan and Budget to produce, or have produced, a sufficient quantity of each
Test Product to enable Cempra to conduct preclinical testing of such Test Products, and to cooperate with Cempra in preparing formulations, conducting feasibility studies, and facilitating such testing. Optimer shall not have any obligation or
responsibility for providing clinical supplies of Test Products or Cempra Products. 
 3.6 Research and Supply
Costs. Cempra shall reimburse Optimer for Optimer’s reasonable, documented internal costs associated with Optimer’s work under the Work Plan and Budget, which shall equal the pro-rated cost of full-time equivalent employees to the
extent used by Optimer in performing its portion of the Research Program. Such cost shall (1) be commercially reasonable based on the applicable employees’ role in performing Optimer’s portion of the Research Program, job title and
responsibilities with Optimer, training, education, and expertise, which shall, in each case, be reasonably appropriate for the tasks performed thereby, and (2) not exceed US$[*] on an annual basis in any event. Cempra shall reimburse
Optimer for the purchasing of key intermediates from Third Parties at Optimer’s cost, which cost shall be commercially reasonable and included in the Budget. Cempra shall also reimburse Optimer for commercially reasonable and documented
external out-of-pocket expenses consistent with the Work Plan and Budget that Optimer incurs for performing such work, including without limitation commercially reasonable and documented payments to any Third Party manufacturer for production of
Macrolide Antibiotics, Test Products and/or Cempra Products. At the end of each calendar quarter, Optimer shall submit to Cempra an invoice that sets forth in reasonable detail the internal costs and external expenses Optimer has incurred in
performing its obligations under the Work Plan and Budget. Cempra shall remit payment to Optimer within thirty (30) days following Cempra’s receipt of such invoice. Any disputes arising between the Parties related to the amounts invoiced
under this Section 3.6 shall be resolved in accordance with Article 12. Notwithstanding anything to the contrary, (i) Cempra shall not be obligated to pay Optimer any amounts with respect to Optimer’s performance of its
obligations under the Research Program except as specifically described in any Budgets established by the Joint Steering Committee, (ii) Optimer shall not incur any Third Party costs in performing under the Research Program, and Cempra shall
not be responsible for the reimbursement of any such Third Party costs, except as approved in advance by the Joint Steering Committee, and (iii) Cempra shall not be obligated to reimburse any costs of Optimer incurred in performing its

  
  

	[*]	Confidential treatment requested; certain information omitted and filed separately with SEC. 

  
 13 

 obligations under the Research Program to the extent such costs are covered by any grant funding provided to
Optimer (including but not limited to any SBIR or other government grants). 
 3.7 Conduct of Research. The Parties
shall use Diligent Efforts to conduct their tasks and responsibilities under the Work Plan and Budget throughout the Research Program. In addition, the Parties shall conduct their tasks and responsibilities under the Research Program in compliance
in all material respects with the requirements of applicable laws, rules and regulations and all applicable GLP to attempt to achieve their objectives consistent with industry standards. Optimer shall use commercially reasonable efforts to
(i) perform in accordance with, maintain, and obtain any awarded, active, or future grants (including but not limited to any SBIR or other government grants) concerning research or development related to the research and development of
Macrolide Antibiotics, Test Products, and/or Cempra Products (collectively, such grants, “Subject Grants”), (ii) ensure payment and receipt of all funds to be provided to Optimer under Subject Grants to the extent covering any of
Optimer’s costs of performing of Optimer’s portion of the Research Program, and (iii) ensure that (a) all Optimer Improvements, Optimer Know-How, and results generated, in each case, under the Subject Grants, and all intellectual
property rights appurtenant to the foregoing (including but not limited to Optimer Patents) shall be owned by Optimer and included in the licenses granted to Cempra hereunder, subject to any nonexclusive rights the United States government may
have in any of the foregoing, by operation of law pursuant to the terms of such Subject Grants. 
 3.8
Acceptance. If, as set forth in the Work Plan, Cempra has responsibility for performing quality control and/or quality assurance testing on Macrolide Antibiotics and/or Test Products supplied by Optimer, Cempra shall have thirty
(30) business days following its receipt of a shipment to confirm that such shipment meets the applicable Specifications. If, as set forth in the Work Plan, Optimer has responsibility for performing quality control and/or quality assurance
testing on Macrolide Antibiotics and/or Test Products supplied by Optimer, Cempra shall be deemed to have accepted any delivery of Macrolide Antibiotics and/or Test Products supplied by Optimer unless Cempra gives Optimer written notice of its
rejection within fifteen (15) business days of delivery, unless any defect in the Macrolide Antibiotics and/or Test Products could not have been identified by reasonable visual examination, in which event Cempra shall not be deemed to have
accepted such Macrolide Antibiotics and/or Test Products until fifteen (15) business days after the date when such defect could first have been reasonably identified by Cempra. If Cempra reasonably rejects in whole or in part any nonconforming
shipment at any time following its receipt thereof, Cempra shall provide Optimer written notice of such rejection within the applicable time period described above. If nonconforming Macrolide Antibiotics or Test Products are delivered to Cempra by
Optimer in the course of the Research Program, Optimer shall, if and as elected by Cempra in its sole discretion (i) use commercially reasonable efforts to replace in a timely manner the nonconforming Macrolide Antibiotics or Test Products at
no additional cost to Cempra or (ii) refund to Cempra any amounts paid to Optimer with respect to the manufacture or supply of such Macrolide Antibiotics or Test Products. 
 4. DEVELOPMENT AND COMMERCIALIZATION 
 4.1 Development Plan;
Reports. The Development of Cempra Products shall be governed by a development plan developed by Cempra, in consultation with the Joint Steering Committee, subject to amendment at any time by Cempra, that describes the proposed overall
program of Development (the “Development Plan”). Cempra shall engage, at its sole expense, a Scientific Advisory Board, which shall, during the Research Term, include one representative of Optimer, initially to be Yoshi Ichikawa,
Ph.D., to review and comment on the Development Plan. During the Research Term, Optimer and the Joint Steering Committee shall have the right to comment and make suggestions with respect to the Development Plan; provided, however, that Cempra shall
have the sole right and responsibility for determining the Development Plan for Cempra Products. Each Party shall conduct its Development of 

  
 14 

 
Products in compliance in all material aspects with the requirements under all applicable laws, rules and regulations, including without limitation applicable GLP, GCP and GMP. Each Party
shall keep the other Party and, during the Research Term, the Joint Steering Committee regularly informed on a semiannual basis via summary updates with respect to its material Development and Commercialization activities and those of its Affiliates
and Third Party sublicensees. Such reports shall be the Confidential Information of a Party and subject to applicable provisions set forth in Article 8. 
 4.2 Regulatory Matters. Cempra shall have control of and be responsible for all regulatory applications, filings and communications with regulatory authorities regarding Cempra Products,
including obtaining Regulatory Approval of Cempra Products, in any jurisdiction in the Territory. Cempra shall keep Optimer regularly informed of its efforts and progress with respect to regulatory matters and approvals on a semiannual basis. Cempra
shall own all the Regulatory Filings it makes and Regulatory Approvals it obtains. Optimer shall have the right of access to such regulatory documents and material for its use in obtaining Regulatory Approval in ASEAN Countries (subject to any
payment obligations under Sections 6.6 and 6.7). Optimer shall cooperate with Cempra in all such regulatory efforts as reasonably requested by Cempra and provide all reasonable assistance to Cempra. If and as requested by Cempra, Optimer
shall be responsible, at the expense of Cempra, which expense shall be reasonable, documented, and agreed upon in advance by the parties, for preparing and providing to Cempra in a timely manner all documents and submissions that relate directly to
the manufacturing of Cempra Product, as reasonably required for Regulatory Filings and Regulatory Approval of the Cempra Product in the Territory, including the CMC of any IND or NDA in electronic format, for filing by Cempra. 

4.3 Manufacture and Supply. With respect to the Territory, and except as may otherwise be specified in the Work Plan and
Budget, Section 3.5, or any separate clinical supply agreement entered into by the Parties, Cempra shall, as between the Parties, be responsible for the manufacture of clinical materials for each Cempra Product, and for the commercial supply of
each Cempra Product, and for all costs associated therewith. Cempra shall use Diligent Efforts to make necessary Regulatory Filings to obtain, or cause a Third Party manufacturer to obtain, Regulatory Approval in the Territory for the manufacture of
Cempra Products. 
 4.4 Development and Commercialization Costs. Cempra shall be responsible for all costs
associated with its Development and Commercialization of the Cempra Products, including the manufacture, marketing and commercialization of such Cempra Products in the Field and in the Territory, provided that, notwithstanding the foregoing,
Cempra’s only obligations to Optimer with respect to any such costs shall solely be as provided for in Section 3 and 4.2, or as otherwise agreed to by the parties in writing. 

4.5 Third Party Commercialization. Subject to the terms and conditions set forth in Section 5.2, Cempra may utilize, at
its discretion, Third Party contractors, distributors, marketing organizations, agents or sublicensees to research, develop, manufacture, supply, promote, market, distribute, and/or sell Cempra Products in one or more countries or jurisdictions in
the Territory. 
 4.6 Pricing. Cempra shall be solely responsible for pricing and other terms of sale for
Cempra Products. 
 4.7 Diligent Efforts; Decision Not to Develop. 

(a) Cempra shall, itself and/or through its Affiliates and Third Party sublicensees, use Diligent Efforts to Develop and
Commercialize Cempra Products in the Territory. In the event that Cempra makes a determination not to Develop and Commercialize at least one Cempra Product 

  
 15 

 
hereunder, Cempra shall promptly notify Optimer in writing of such determination in writing. If Cempra (itself or through its Affiliates or Third Party sublicensees) does not use Diligent Efforts
as set forth in this Section 4.7(a), or if Cempra makes a determination not to further Develop and Commercialize at least one Cempra Product hereunder, then Optimer may terminate this Agreement in accordance with Section 9.3(a) below;
provided, however, that if Cempra has notified Optimer in writing of a determination not to Develop and Commercialize at least one Cempra Product, then the cure period set forth in Section 9.3(a) shall not apply. 

(b) Optimer shall, itself and/or through its Affiliates and Third Party sublicensees, use Diligent Efforts to develop and
commercialize Products in ASEAN Countries. In the event that Optimer makes a determination not to Develop and Commercialize at least one Product hereunder in ASEAN Countries, Optimer shall promptly notify Cempra in writing of such determination in
writing. If Optimer (itself or through its Affiliates or Third Party sublicensees) does not use Diligent Efforts as set forth in this Section 4.7(b), or if Optimer makes a determination not to further Develop and Commercialize at least one
Product in ASEAN Countries hereunder, then Cempra may terminate this Agreement in accordance with Section 9.3(a) below; provided, however, that if Optimer has notified Cempra in writing of a determination not to Develop and Commercialize
at least one Product in ASEAN Countries, then the cure period set forth in Section 9.3(a) shall not apply. 
 5. LICENSES AND
RELATED RIGHTS 
 5.1 License to Cempra. Optimer hereby grants to Cempra and its Affiliates an exclusive license,
with the right to sublicense as set forth in Section 5.2, under the Optimer Technology and the Optimer Improvements to make, have made, use, sell, offer for sale and import Macrolide Antibiotics, Test Products, and Cempra Products in the Field
in the Territory. It is understood and agreed that Optimer retains the right under the Optimer Technology to conduct activities allocated to Optimer in the Research Program. 
 5.2 Cempra Sublicensing. Cempra and its Affiliates shall have the right to sublicense their rights under Section 5.1 to one or more Third Parties. Cempra shall promptly provide
Optimer a written copy of each such sublicense (and each amendment thereto, if any), and in no event more than ten (10) days following its execution, provided that Cempra may redact any portions of such sublicenses (or amendments)
disclosing sublicensees’ proprietary information, technology, or research and development plans as reasonably necessary to comply with any confidentiality provisions of such sublicense. Each sublicense shall be consistent with the terms and
conditions of this Agreement. For purposes of this Agreement, a Third Party to whom Cempra or its Affiliate grants exclusive rights to market one or more Cempra Products in a given territory shall be deemed a “sublicensee” of Cempra
hereunder for such territory. 
 5.3 [*]Intellectual Property. If Optimer licenses any rights to any Macrolide
Antibiotics from [*] or any affiliate thereof during the term of this Agreement, it shall provide prompt written notice thereof to Cempra, identifying such licensed intellectual property, and, if and as elected by Cempra in writing its sole
discretion, (i) Patents to which Optimer obtains rights under such a license shall be deemed included in Optimer Patents for purposes of this Agreement and (ii) Know-How to which Optimer obtains rights under such a license shall be deemed
include in Optimer Know-How. 
 5.4 Optimer Rights in ASEAN Countries. Cempra hereby grants to Optimer and its
Affiliates an exclusive license, with the right to sublicense as set forth in Section 5.5, in the Field under Cempra Patents and Cempra Know-How to make, have made, use, sell, offer for sale and import Optimer 

 
  

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
 16 

 Products in ASEAN Countries, which license shall include a right of reference to all Regulatory Filings,
Regulatory Approvals, and supporting data and documentation of Cempra with respect to Cempra Products. 
 5.5 Optimer
Sublicensing. Optimer and its Affiliates shall have the right to sublicense their rights under Section 5.4 to one or more Third Parties. Optimer shall promptly provide Cempra a written copy of each such sublicense (and each
amendment thereto, if any), and in no event more than ten (10) days following its execution, provided that Optimer may redact any portions of such sublicenses (or amendments) disclosing sublicensees’ proprietary information,
technology, or research and development plans as reasonably necessary to comply with any confidentiality provisions of such sublicense. Each sublicense shall be consistent with the terms and conditions of this Agreement. For purposes of this
Agreement, a Third Party to whom Optimer or its Affiliate grants exclusive rights to market one or more Optimer Products in a given territory shall be deemed a “sublicensee” of Optimer hereunder for such territory 

5.6 Bankruptcy. All rights and licenses granted under or pursuant to any section of this Agreement are, and shall otherwise
be deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy Code, licenses of rights to “intellectual property” as defined under Section 101(35A) of the U.S. Bankruptcy Code. The Parties shall retain and
may fully exercise all of their respective rights and elections under the U.S. Bankruptcy Code. The Parties agree that a Party that is a licensee of such rights under this Agreement shall retain and may fully exercise all of its rights and
elections under the U.S. Bankruptcy Code, and that upon commencement of a bankruptcy proceeding by or against the licensing Party (such Party, the “Involved Party”) under the U.S. Bankruptcy Code, the other Party (such
Party, the “Noninvolved Party”) shall be entitled to a complete duplicate of or complete access to (as such Noninvolved Party deems appropriate), any such intellectual property and all embodiments of such intellectual property,
provided the Noninvolved Party continues to fulfill its payment or royalty obligations as specified herein in full. Such intellectual property and all embodiments thereof shall be promptly delivered to the Noninvolved Party (a) upon any such
commencement of a bankruptcy proceeding upon written request therefore by the Noninvolved Party, unless the Involved Party elects to continue to perform all of its obligations under this Agreement or (b) if not delivered under (a) above,
upon the rejection of this Agreement by or on behalf of the Involved Party upon written request therefor by the Noninvolved Party. The foregoing is without prejudice to any rights the Noninvolved Party may have arising under the U.S. Bankruptcy
Code or other applicable law. 
 5.7 Disclosure of Information. Upon execution of this Agreement and thereafter
during the term hereof, each party shall disclose to the other party, in confidence under the terms of Article 8 hereof, (a) all relevant Information as shall become available to it relating to the Macrolide Antibiotics, Test Products and
Cempra Products, and (b) all relevant Information as shall become available to it relating to the safety and efficacy of each Macrolide Antibiotic, Test Product, and Cempra Product to the extent necessary or useful to develop or manufacture a
Cempra Product. Optimer will use reasonable efforts to disclose to Cempra or, if and as requested by Cempra, to the FDA all relevant Information in its possession required for Cempra to register for sale or obtain approval for sale of each
Cempra Product. 
 5.8 No Implied Licenses. Other than those rights and licenses expressly granted herein, no
other rights or licenses are granted or shall be deemed granted under this Agreement by either Party. 

  
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 6. FINANCIAL TERMS 
 6.1 Upfront Payment. Cempra shall issue Optimer one hundred four thousand one hundred sixty-six (104,166) shares of Cempra common stock ([*]% of total number of outstanding shares as
determined on a fully-diluted basis as of the Effective Date), within thirty (30) after the Effective Date of this Agreement. The Cempra common stock issued to Optimer pursuant to this Section 6.1 shall not be subject to dilution until
after Cempra closes on an Equity Investment (as defined below). Upon closing of an Equity Investment, Cempra shall issue Optimer additional shares of Cempra common stock sufficient to ensure that the total number of shares of Cempra common
stock held by Optimer immediately following such Equity Investment equals the percentage of Cempra’s total number of outstanding shares (as calculated on a fully-diluted basis immediately following the Equity Investment) noted below:

  

			
	 Gross Proceeds to Cempra

in Equity Financing
	  	Percentage of Cempra 
Common
Stock to be Held by Optimer
		
	 $[*] to $[*]
	  	[*]%
		
	 $[*] to $[*]
	  	[*]%
		
	 $[*] to $[*]
	  	[*]%
		
	 $[*] to $[*]
	  	[*]%
		
	 $[*] or more
	  	[*]%

 Following the first such issuance of additional shares, all shares issued to Optimer will be subject to dilution on a
pari passu basis with the Cempra common stock held by other holders of Cempra common stock and Optimer shall not be entitled to any further shares of stock under this Section 6.1. For purposes of this Agreement, an “Equity
Investment” shall mean Cempra’s issuance and sale of equity securities to venture capital, institutional, corporate, or private investors resulting in aggregate gross proceeds to Cempra of at least [*] [*]. The issuances of stock to
Optimer under this Section 6.1 shall be done pursuant to separate Subscription Agreements, a form of which is attached hereto as Schedule 6.1(1), and the Cempra common stock held by Optimer shall be subject to a shareholders
agreement, which shall initially be in the form of set forth at Schedule 6.1(2). Optimer agrees to enter into reasonable or customary agreements required by any future equity investors regarding subjecting Optimer’s shares of Cempra
common stock to rights of first refusal and co-sale, such rights to terminate on an initial public offering of Cempra stock pursuant to a registration statement filed pursuant to the Securities Act of 1933, as amended. 

6.2 Milestone Payments to Optimer. 
 (a) Cempra shall pay to Optimer a milestone payment (the “Phase 1 Milestone Payment”) in the amount of $500,000 upon Cempra’s, its Affiliate’s, or their
sublicensee’s completion of the first Phase 1 Trial of a Cempra Product resulting in data reasonably sufficient to support the conduct of a Phase 2 Trial with respect to such Cempra Product (the “Phase 1 Milestone”), and the
Phase 1 Milestone Payment shall be payable in cash or Cempra capital stock, as further described below. Cempra shall notify Optimer within thirty (30) days of its determination that a Phase 1 Milestone has occurred. Optimer shall indicate in
writing, within ten (10) business days of such notice from Cempra, whether it 
  

 

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
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 elects the Phase 1 Milestone Payment to be paid in cash or shares of Cempra capital stock having a Fair
Market Value, as calculated as of the date the Phase 1 Milestone is achieved, equal to the Phase 1 Milestone Payment; in the absence of such election within such ten (10) business day period, Cempra shall be entitled to make such election in
its sole discretion. The Phase 1 Milestone Payment shall be paid (or, if to be paid in Cempra capital stock, such stock shall be issued) no later than twenty (20) days after the earlier of (i) the date on which Optimer provides its written
election, as described above, or (ii) the expiration of the ten (10) business day period referenced above. Only one Phase 1 Milestone Payment shall be payable by Cempra under this Agreement, regardless of the number of Cempra Products or
indications therefor developed by Cempra, its Affiliates, or their sublicensees under this Agreement. 
 (b) Cempra shall
pay to Optimer a milestone payment (each, a “Phase 2 Milestone Payment”) in the amount of $1,000,000 upon Cempra’s, its Affiliate’s, or their sublicensee’s completion of the first Phase 2 Trial of each Cempra Product
resulting in data reasonably sufficient to support the conduct of a Phase 3 Trial with respect to such Cempra Product (the “Phase 2 Milestone”), and the initial Phase 2 Milestone Payment shall be payable in cash or Cempra
capital stock, as further described below. Cempra shall notify Optimer within thirty (30) days of its determination that a Phase 2 Milestone has occurred. Optimer shall indicate in writing, within ten (10) business days of the initial such
notice from Cempra, whether it elects the initial Phase 2 Milestone Payment to be paid in cash or shares of Cempra capital stock having a Fair Market Value, as calculated as of the date the initial Phase 2 Milestone is achieved, equal to the Phase 2
Milestone Payment; in the absence of such election within such ten (10) business day period, Cempra shall be entitled to make such election in its sole discretion. The initial Phase 2 Milestone Payment shall be paid (or, if to be paid in Cempra
capital stock, such stock shall be issued) no later than twenty (20) days after the earlier of (i) the date on which Optimer provides its written election, as described above, or (ii) the expiration of the ten (10) business day
period referenced above; all other Phase 2 Milestone Payments shall be paid in immediately available funds, pursuant to Section 6.9 below, no later than thirty (30) days following the achievement of such Phase 2 Milestone. Only one Phase 2
Milestone Payment shall be payable by Cempra under this Agreement with respect to each Cempra Product, regardless of the number of indications therefor developed by Cempra, its Affiliates, or their sublicensees under this Agreement. 

(c) In addition to the Phase 2 Milestone Payments, in the event that (i) Cempra or an Affiliate thereof sublicenses
rights for Development and Commercialization of a Cempra Product to a Third Party sublicensee and (ii) Cempra, an Affiliate, or such sublicensee completes a Phase 3 Trial of such Cempra Product resulting in data sufficient to support
Regulatory Approval of such Cempra Product (the date upon which both of the foregoing have been achieved, the “Sublicensee Milestone”), then Cempra shall pay to Optimer (a) the following amounts with respect to each of the
first two (2) Cempra Products to achieve the Sublicensee Milestone: (1) $[*] within thirty (30) days after each such Cempra Product achieves the Sublicensee Milestone (the “Initial Sublicensee Milestone Payments”) and
(2) [*] percent ([*]%) of all Sublicensing Revenue, if any, received in excess of $[*] with respect to each such Cempra Product from the Third Party sublicensee(s) for such Cempra Product (to be paid to Optimer within thirty
(30) days of Cempra’s receipt of each applicable payment of Sublicensing Revenue from such sublicensee(s)) (“Trailing Sublicensee Milestone Payments”) and, with respect to each of the subsequent two Cempra Products to
achieve the Sublicensee Milestone, (b) $[*] within thirty (30) days after the date upon which such subsequent Cempra Product achieves the Sublicensee Milestone (“Subsequent Sublicensee Milestone Payments”; collectively,
with all of the foregoing payments described in this subsection (c), the “Sublicensee Milestone Payments”). Cempra shall notify Optimer within thirty (30) days of each of the first four occurrences of the Sublicensee
Milestone. 
  
  

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
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 Notwithstanding anything to the contrary, (i) the Initial Sublicensee Milestone Payment
shall only be payable by Cempra [*] under this Agreement, (ii) an Initial Sublicensee Milestone Payment shall not be due or payable under this Agreement with respect to a particular Cempra Product if the Initial Cempra Milestone Payment
(as defined in Section 6.2(d) below) becomes due for such Cempra Product prior to the date upon which the applicable Initial Sublicensee Milestone Payment becomes due for such Cempra Product, (iii) the aggregate, combined, total
number of Subsequent Sublicensee Milestone Payments and Subsequent Cempra Milestone Payments due under this Agreement shall be [*] (regardless of the number of Cempra Products or indications therefor), and (iv) a Subsequent Sublicensee
Milestone Payment shall not be due or payable under this Agreement with respect to a particular Cempra Product if the Subsequent Cempra Milestone Payment (as defined in Section 6.2(d) below) becomes due with respect to such Cempra
Product prior to the date upon which the Subsequent Sublicensee Milestone Payment becomes due with respect thereto. Except with respect to Trailing Sublicensee Milestone Payments, and notwithstanding anything to the contrary in this Agreement, the
total possible combined aggregate amount due Optimer under this Section 6.2(c) and Section 6.2(d) below shall not exceed, and Cempra shall not be obligated to pay Optimer any amounts in excess of, $[*]. 

(d) In addition to the Phase 2 Milestone Payments, if, prior to the occurrence of a Sublicensee Milestone with respect to a Cempra
Product, an [*] is obtained (the “Cempra Milestone”), Cempra shall pay Optimer (i) $[*] with respect to each of the first [*] Cempra Products to achieve the Cempra Milestone (the “Initial Cempra Milestone
Payments”) and (ii) $[*] with respect to each of the subsequent two Cempra Products to achieve the Cempra Milestone (the “Subsequent Cempra Milestone Payments”; collectively, with the Initial Cempra Milestone Payment,
the “Cempra Milestone Payments”) within, in each case, thirty (30) days of the first anniversary of such Cempra Product’s achievement of the Cempra Milestone. 

Notwithstanding anything to the contrary, each Cempra Milestone Payment (i) shall only be payable by Cempra once under this
Agreement with respect to a particular Cempra Product, regardless of the number of indications therefor, (ii) an Initial Cempra Milestone Payment shall not be due or payable under this Agreement with respect to a particular Cempra Product if an
Initial Sublicensee Milestone Payment (as defined in Section 6.2(c) above) becomes due with respect to such Cempra Product prior to the date upon which the Initial Cempra Milestone Payment becomes due with respect to such Cempra
Product, (iii) the aggregate, combined, total number of Subsequent Sublicensee Milestone Payments and Subsequent Cempra Milestone Payments due under this Agreement shall be [*] (regardless of the number of Cempra Products or indications
therefor), and (iv) a Subsequent Cempra Milestone Payment shall not be due or payable under this Agreement with respect to a particular Cempra Product if the Subsequent Sublicensee Milestone Payment (as defined in
Section 6.2(c) above) becomes due with respect to such Cempra Product prior to the date upon which the Subsequent Cempra Milestone Payment becomes due with respect thereto. 

(e) As a condition to the issuance(s) of Cempra capital stock to Optimer pursuant to
Sections 6.2(a) and/or 6.2(b), as applicable, Optimer shall enter into reasonable or customary agreements (including but not limited to subscription or purchase agreements) substantially consistent with those entered into by other
holders of such shares of stock, including but not limited to investors, as applicable, and which may concern the issuance of such stock, voting provisions, and/or rights of first refusal and co-sale with respect to such shares. 

6.3 Royalty Payments to Optimer. For the duration of the applicable Royalty Term for each Cempra Product, Cempra shall pay to
Optimer the following royalty payments, subject to adjustment 
  

 

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 as described in Sections 6.4 and 6.5, based on Net Sales of Cempra Products sold in the Territory
by Cempra, its Affiliates, and their Third Party sublicensees: 
 (i) [*] percent ([*]%) of Net Sales for the first $[*] of
aggregate worldwide Net Sales of Cempra Products sold by Cempra, its Affiliates, and their Third Party sublicensees in a particular calendar year; and 
 (ii) [*] percent ([*]%) of Net Sales for the portion, if any, of aggregate worldwide Net Sales of Cempra Products sold by Cempra, its Affiliates, and their Third Party sublicensees exceeding $[*] in a
particular calendar year. 
 As an example of the royalty calculation contemplated above, if aggregate worldwide Net Sales of Cempra
Products by Cempra, its Affiliates, and their Third Party sublicensees in a particular calendar year total $[*], Cempra shall owe Optimer $[*] under this Section 6.3 ([*]% × $[*] = $[*]; [*]% of $[*] = $[*];
$[*] + $[*] = $[*]). 
 6.4 Third Party Royalties on Cempra Products. In the event that:

 (a) a Cempra Product is deemed by a final, unappealable decision of a court of competent jurisdiction to infringe a
claim of a patent(s) owned or controlled by a Third Party in any given country of the Territory, and Cempra, an Affiliate thereof, or any sublicensee thereof licenses such patent(s) in settlement of such claims (“Cempra
Infringement License”), 
 (b) Cempra, an Affiliate thereof, or any sublicensee of either of the foregoing
determines that it is commercially, reasonably necessary or advisable to pay royalties to a Third Party to obtain a license to practice any Third Party’s rights in order to manufacture, use, Commercialize or Develop a Cempra Product in any
given country of the Territory (“Cempra Necessary License”), or 
 (c) it would be useful to obtain
a license to practice any Third Party’s rights that could improve, enhance, or modify a Cempra Product in any given country of the Territory (“Cempra Improvement License”), as determined reasonably and in good faith by Cempra,
an Affiliate thereof, or any sublicense of either of the foregoing, then Cempra may deduct any fees, milestones or royalties paid for Cempra Infringement Licenses, Cempra Necessary Licenses and Cempra Improvement Licenses due to such Third
Parties (or such amounts paid by Cempra, its Affiliate, or any sublicensee of either of the foregoing in settlement of such infringement action) (collectively, all of the foregoing, “Third Party Royalties”) from the royalties
otherwise due to Optimer with respect to Net Sales; provided, however, that, notwithstanding the foregoing, the total amount due to Optimer under this Agreement with respect to Net Sales for Cempra Products sold by Cempra and its Affiliates any
particular calendar quarter shall not be reduced by more than [*] percent ([*]%) as a result of any such deduction, and any amounts not deducted in a calendar quarter shall be carried forward for deduction in the subsequent calendar quarter(s),
subject to such [*] percent ([*]%) limitation in each case. 
 6.5 Cempra Compulsory Licenses. Should a
compulsory license be granted, or be the subject of a possible grant, to a Third Party under the applicable laws of any country in the Territory under the Optimer Patents and/or Optimer Know-How, or to any Cempra Product, the Party receiving notice
thereof or otherwise becoming aware thereof shall promptly notify the other Party thereof, including any material information concerning such compulsory license, and the applicable royalty rate payable hereunder for sales of Cempra Products in such
country will be adjusted to match any lower 
  
  

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 royalty rate granted to such Third Party for such country with respect to the sales of such Cempra Products,
subject to any adjustments pursuant to Section 6.4 above. 
 6.6 Milestone Payments to Cempra. For each of
the first two Optimer Products to achieve the Optimer Milestone (as defined below), Optimer shall, within two (2) years of the earlier of (i) the First Commercial Sale of an Optimer Product in any ASEAN Country by Optimer, an
Affiliate thereof, or any sublicensee of either of the foregoing or (ii) Regulatory Approval of an Optimer Product in any ASEAN Country, pay Cempra $1,000,000 with respect to such Optimer Product (the first to occur of the foregoing with
respect to an Optimer Product, the “Optimer Milestone”). Such payment shall be due with respect solely to each of the first two (2) Optimer Products to achieve the Optimer Milestone. Optimer shall notify Cempra in writing
within thirty days of each occurrence of the Optimer Milestone. 
 6.7 Royalties to Cempra. For the duration of the
applicable Royalty Term for each Optimer Product, Optimer shall pay to Cempra the following royalty payments based on Net Sales of Optimer Products in ASEAN Countries by Optimer, its Affiliates, and their Third Party sublicensees: 

(i) [*] percent ([*]%) of Net Sales for the first $[*] of aggregate worldwide Net Sales of Optimer Products by Optimer, its Affiliates,
and their Third Party sublicensees in a particular calendar year; and 
 (ii) [*] percent ([*]%) of Net Sales for the
portion, if any, of aggregate worldwide Net Sales of Optimer Products by Optimer, its Affiliates, and their Third Party sublicensees exceeding $[*] million in a particular calendar year. 

As an example of the royalty calculation contemplated above, if aggregate Net Sales of Optimer Products in a particular calendar year total $[*], Optimer
shall owe Cempra $[*] under this Section 6.7 ([*]% × $[*] = $[*]; [*]% of $[*] = $[*]; $[*] + $[*] = $[*]). 
 6.8 Third Party Royalties on Optimer Products. In the event that: 

(a) a Optimer Product is deemed by a final, unappealable decision of a court of competent jurisdiction to infringe a claim of a
patent(s) owned or controlled by a Third Party in any given country of the Territory, and Optimer, an Affiliate thereof, or any sublicensee thereof licenses such patent(s) in settlement of such claims (“Optimer Infringement
License”), 
 (b) Optimer, an Affiliate thereof, or any sublicensee of either of the foregoing determines that
it is commercially, reasonably necessary or advisable to pay royalties to a Third Party to obtain a license to practice any Third Party’s rights in order to manufacture, use, Commercialize or Develop an Optimer Product in any given country of
the Territory (“Optimer Necessary License”), or 
 (c) it would be useful to obtain a license to
practice any Third Party’s rights that could improve, enhance, or modify a Optimer Product in any given country of the Territory (“Optimer Improvement License”), as determined reasonably and in good faith by Optimer, an
Affiliate thereof, or any sublicense of either of the foregoing, then Optimer may deduct any fees, milestones or royalties paid for Optimer Infringement Licenses, Optimer Necessary Licenses and Optimer Improvement Licenses due to such Third
Parties (or such amounts paid by Optimer, its Affiliate, or any sublicensee of either of the foregoing in settlement of such infringement action) (collectively, all of the foregoing, “Third Party Royalties”) from the royalties
otherwise due to Cempra with respect to Net Sales; provided, however, that, notwithstanding the foregoing, the total amount due to Cempra under this Agreement with respect to 

 
  

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 Net Sales for Optimer Products sold by Optimer and its Affiliates any particular calendar quarter shall not
be reduced by more than [*] percent ([*]%) as a result of any such deduction, and any amounts not deducted in a calendar quarter shall be carried forward for deduction in the subsequent calendar quarter(s), subject to such [*] percent ([*]%)
limitation in each case. 
 6.9 Optimer Compulsory Licenses. Should a compulsory license be granted, or be the
subject of a possible grant, to a Third Party under the applicable laws of any country in the Territory under the Cempra Patents and/or Cempra Know-How, or to any Optimer Product, the Party receiving notice thereof or otherwise becoming aware
thereof shall promptly notify the other Party thereof, including any material information concerning such compulsory license, and the applicable royalty rate payable hereunder for sales of Optimer Products in such country will be adjusted to match
any lower royalty rate granted to such Third Party for such country with respect to the sales of such Optimer Products, subject to any adjustments pursuant to Section 6.8 above. 

6.10 Payments and Payment Reports. Except as otherwise provided herein, all royalties and payments due under this
Section 6 shall be paid within ninety (90) days of the end of the relevant calendar quarter for which the applicable Net Sales occur and/or revenues are received, subject, with respect to Net Sales, as applicable, by Third Party
sublicensees, to any longer reporting periods which may be reasonably agreed to by Cempra, Optimer, or their Affiliates with respect to such sublicensees. Each royalty payment shall be accompanied by a statement stating (as applicable) the
number, description, and aggregate Net Sales, by country, of each Product sold during the relevant calendar quarter by Cempra or Optimer, as applicable, and their respective Affiliates and Third Party sublicensees and detailing the calculation of
royalties due for such calendar quarter, as well as, with respect to Cempra’s reporting obligations, an accounting of Sublicense Revenues received in the applicable calendar quarter. 

6.11 Payment Method. Except with respect to any milestone payments due under Sections 6.2 (a) and (b) that are
paid in Cempra stock in accordance therewith, all payments due under this Agreement shall be made by bank wire transfer in immediately available funds to an account designated by the Party owed such payments. All payments hereunder shall be made in
the legal currency of the United States of America. 
 6.12 Taxes. It is understood and agreed between the
Parties that any payments made under Section 6.1, 6.2, or 6.6 of this Agreement are inclusive of any value added or similar tax imposed upon such payments. In addition, in the event any of the payments made by either Party
(the “Paying Party”) pursuant to Article 6 become subject to withholding taxes under the laws of any jurisdiction, such amounts payable or, in the case of stock to be issued to Optimer pursuant to
Sections 6.2(a) or (b), as applicable, shares issuable to the other Party (the “Paid Party”) shall be reduced by the amount of taxes deducted and withheld, and the Paying Party shall pay the amounts of such taxes to the
proper Governmental Authority in a timely manner and promptly transmit to the Paid Party an official tax certificate or other evidence of such tax obligations together with proof of payment from the relevant Governmental Authority of all amounts
deducted and withheld sufficient to enable the Paid Party to claim such payment of taxes. Any such withholding taxes required under applicable law to be paid or withheld shall be an expense of, and borne solely by, the Paid Party. The Paying Party
will provide the Paid Party with reasonable assistance to enable the Paid Party to recover such taxes as permitted by law. 

6.13 Blocked Currency. In each country where the local currency is blocked and cannot be removed from the country under such
country’s applicable law, royalties accrued in that country shall be paid to a Party in the country in local currency by deposit in a local bank designated by such Party, unless the Parties otherwise agree. 

 
  

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 6.14 Sublicenses. For avoidance of doubt, the Parties agree that in the event
that a Party grants licenses or sublicenses to Third Parties to sell Products, the licensing (or sublicensing) Party shall use commercially reasonable efforts to include in such licenses or sublicenses an obligation for the licensee or
sublicense to account for and report its sales of Products on a basis reasonably sufficient to enable payment of royalties hereunder with respect to such sales as if such sales of the licensee or sublicensee were Net Sales of the applicable Party.

 6.15 Foreign Exchange. Conversion of a Party’s Net Sales recorded in local currencies to U.S. dollars
will be performed by such Party in a manner consistent with such Party’s normal practices used to prepare its audited financial statements for external reporting purposes, provided that such practices use a widely accepted source of published
exchange rates. Each Party shall notify the other of the conversion method(s) used by it for such purposes. 
 6.16
Interest. If either Party fails to make any payment when due to the other Party under this Agreement, then interest shall accrue on a daily basis at a rate equal to the thirty (30) day U.S. dollar LIBOR rate effective for the date
that payment was due, as published by The Wall Street Journal. The obligation to pay interest on such late payments set forth herein shall not be construed to limit or restrict a Party’s right to terminate this Agreement in accordance
with the terms and conditions of Section 9.3. 
 6.17 Records; Audits. Each Party shall keep or cause to be
kept such records as are required to determine, in a manner consistent with generally accepted accounting principles in the United States, the sums or credits due under this Agreement, including, but not limited to Net Sales. At the request
(and expense) of either Party, the other Party and its Affiliates and sublicensees shall permit an independent certified public accountant appointed by such Party and reasonably acceptable to the other Party, at reasonable times not more than
once a year and upon reasonable notice, to examine only those records as may be necessary to determine, with respect to any calendar year ending not more than three (3) years prior to such Party’s request, the correctness or completeness
of any royalty report or payment made under this Agreement. The Party requesting the audit shall bear the full cost of the performance of any such audit, unless such audit discloses a variance adverse to the Party requesting the audit of more than
five percent (5%) from the amount of the original invoice, report, royalty or payment calculation, in which case the Party being audited shall bear the reasonable, documented cost of the performance of such audit. Each Party shall promptly pay
to the other Party the amount of any underpayment of royalties revealed by an examination and review. Any overpayment by a Party of royalties or any other amount paid to the other Party revealed by an examination and review shall, in the overpaying
Party’s sole discretion, (i) be fully-creditable against future payments under this Agreement or (ii) refunded to the overpaying Party within sixty (60) business days of its request. 

7. Intellectual Property 

7.1 General Principles. 
 (a) The Optimer Technology existing as of the Effective Date shall, subject to the rights granted under this Agreement, remain the sole property of Optimer and may be licensed by Optimer for any
purpose that is not inconsistent nor in conflict with this Agreement. 
 (b) All right, title, and interest in any
and all Know-How or Inventions generated, conceived or reduced to practice by employees, agents or independent contractors of Optimer or its Affiliates, solely or jointly with employees, agents or independent contractors of Cempra or any Affiliate
thereof, in connection with the performance of Optimer’s obligations under this Agreement, or that relate to Cempra Products in any manner, except any such Know-How or Inventions that are generated using grant monies provided by the
United States government to Optimer and which are, therefore, subject to 

  
 24 

 
the limitations and requirements of such grants with respect to such intellectual property (collectively, all of the foregoing, “Optimer Inventions”), and all right, title, and
interest in all intellectual property rights appurtenant thereto, shall vest in Cempra, subject to the terms of the license grant set forth in Article 5 and Optimer’s ownership of the Optimer Technology and sole or joint ownership
(as applicable) of Optimer Improvements. Optimer shall notify Cempra promptly in writing and in reasonable detail of any Optimer Inventions. Optimer hereby assigns all right, title, and interest to Optimer Inventions and all intellectual
property rights appurtenant thereto to Cempra, and agrees to take all actions and execute all documents, and to cause its Affiliates, employees, agents, and independent contractors to execute all documents and take all actions, requested by Cempra
to effect the purposes of the foregoing. Optimer hereby appoints Cempra as it attorney to effect on its behalf any assignment of the Optimer Inventions which Optimer has failed to make to Cempra within 7 days in accordance with the terms of
this Section with the right but not the obligation to do any and all acts and things reasonably necessary to effect unconditionally such assignment including the right for Cempra to execute all deeds, documents or instruments and swear any
oaths or declarations in the name of and on behalf of Optimer necessary for such purpose. Cempra’s appointment as attorney under this Section is given to secure Cempra’s interest in the Optimer Inventions and intellectual property
rights appurtenant thereto and to secure the performance of Optimer’s obligations to assign the Optimer Inventions and intellectual property rights appurtenant thereto in the event of termination and such appointment shall be perpetual and
irrevocable, notwithstanding Optimer entering into liquidation, being wound-up or dissolved or having a receiver, manager, administrator, administrative receiver or similar person appointed over any of its assets. 

(c) Subject to Section 7.1(d) below, Optimer and Cempra shall each own any inventions conceived solely by its own
employees or agents, other than those inventions that are Optimer Inventions (“Other Sole Inventions”), including but not limited to (i) Know-How, conceived or reduced to practice during the term of this Agreement or
(ii) such inventions generated using grant monies provided by the United States government to Optimer and which are, therefore, subject to the limitations and requirements of such grants with respect to such intellectual property. Subject
to Section 7.1(d) below, Cempra and Optimer shall each own an undivided one-half interest in any inventions conceived jointly by employees or agents of both Cempra and Optimer, other than those inventions that are Optimer Inventions
(“Other Joint Inventions”), including but not limited to (i) Know-How conceived or reduced to practice during the term of this Agreement and (ii) such inventions generated using grant monies provided by the
United States government to Optimer and which are, therefore, subject to the limitations and requirements of such grants with respect to such intellectual property. Subject to Sections 7.1(d), 7.2, and 7.3 below, each Party may use,
protect, license and enforce its own Other Sole Inventions in its discretion. The determinations of inventorship, and each Party’s rights and interests with respect to Other Joint Inventions and jointly created Know-How relating to such Other
Joint Inventions, shall be the same as provided with respect to patents under United States law, and in particular, subject in all cases to the provisions of this Agreement, either Party may exploit or grant licenses under such Other Joint
Inventions and jointly created Know-How without a duty of accounting to the other Party. 
 (d) Notwithstanding
anything to the contrary, the exclusive license granted in Section 5.1 above shall include rights to Optimer Improvements, Optimer’s rights in Other Joint Inventions and Other Sole Inventions, Optimer’s rights in all Patents claiming
any of the foregoing, and Optimer’s rights in all Know-How related to all of the foregoing, subject to any nonexclusive rights the United States government may have in any of the foregoing, by operation of law pursuant to the terms of any
applicable grants. 
 (e) Notwithstanding anything to the contrary, the exclusive license granted in Section 5.4
above shall include rights to Cempra’s rights in Other Joint Inventions and Other Sole Inventions, Cempra’s rights in all Patents claiming any of the foregoing, and Cempra’s rights in all Know-How related to all of the foregoing.

  
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 7.2 Patent Prosecution and Maintenance of Optimer Patents. Optimer shall be
responsible for, and be obligated to the extent it is commercially reasonable to diligently pursue, or to cause Optimer’s licensors to diligently pursue, the preparation, filing, prosecution (including but not limited to, by conducting
interferences, oppositions and reexaminations or other similar proceedings), maintenance (by timely paying all maintenance fees, renewal fees and other applicable fees and costs), and extension of Patents within the Optimer Patents (including
but not limited to those claiming Optimer’s Other Sole Inventions). Optimer will regularly advise Cempra of the status of all pending Optimer Patent applications, including any related hearings or other proceedings, and, at Cempra request, will
provide Cempra with copies of all documentation concerning such applications, including all correspondence to and from any Governmental Authority. Optimer shall consult with and obtain written consent from Cempra prior to abandoning any Optimer
Patent, which consent shall not be unreasonably withheld, delayed, or conditioned. Optimer will solicit Cempra’s advice and review of such applications and important prosecution matters related thereto in reasonably sufficient time prior to
filing thereof, and will take into account Cempra’s reasonable comments related thereto. The costs of prosecution and maintenance of Optimer Patents shall be borne by Optimer. 

7.3 Patent Prosecution and Maintenance of Cempra Patents. Cempra shall be responsible for, and be obligated to the extent it
is commercially reasonable to diligently pursue, or to cause Cempra’s licensors to diligently pursue, the preparation, filing, prosecution (including but not limited to, by conducting interferences, oppositions and reexaminations or other
similar proceedings), maintenance (by timely paying all maintenance fees, renewal fees and other applicable fees and costs), and extension of Patents within the Cempra Patents (including but not limited to those claiming Cempra’s Other
Sole Inventions). Cempra will regularly advise Optimer of the status of all pending Cempra Patent applications, including any related hearings or other proceedings, and, at Optimer’s request, will provide Optimer with copies of all
documentation concerning such applications, including all correspondence to and from any Governmental Authority. Cempra shall consult with and obtain written consent from Optimer prior to abandoning any Cempra Patent, which consent shall not be
unreasonably withheld, delayed, or conditioned. Cempra will solicit Optimer’s advice and review of such applications and important prosecution matters related thereto in reasonably sufficient time prior to filing thereof, and will take into
account Optimer’s reasonable comments related thereto. The costs of prosecution and maintenance of Cempra Patents shall be borne by Cempra. 
 7.4 Patent Prosecution and Maintenance of Patents Claiming Other Joint Inventions. Subject to Sections 7.7 and 7.8, for Patents claiming Other Joint Inventions (“Joint
Invention Patents”), Cempra will have, without prejudice to ownership, the first right to prepare, file and prosecute such Patent applications and maintain any resulting Patents; provided, however, that Cempra may request that Optimer
undertake such responsibilities upon written notice to Optimer, and Optimer may agree to do so, in its sole discretion. If Optimer does not agree to undertake such responsibilities within ten (10) days of such request with respect to any such
Patents, Cempra shall not have any further obligations to prosecute or maintain such Patents. Within nine (9) months after the filing date of a Patent application in respect of an Other Joint Invention, the Party filing such application will
request that the other Party identify those non-priority, non-PCT (“foreign”) countries in which the other Party desires that the filing Party file corresponding Patent applications. Within thirty (30) days after receipt of such
request, the other Party will provide to the filing Party a written list of such foreign countries in which the other Party wishes to effect corresponding foreign patent application filings. The Parties will then attempt to agree on the particular
countries in which such applications will be filed, provided that in the event agreement is not reached, the issue shall be resolved pursuant to Section 12.3 (“Designated Foreign Filings”). Thereafter, the filing Party will
effect all such Designated Foreign Filings in a timely manner. It is presumed unless otherwise agreed in writing by the Parties, that a corresponding PCT application will be filed designating all PCT member countries. Should the Party filing the
priority application not agree to file or cause to be 

  
 26 

 
filed a Designated Foreign Filing, the other Party will have the right to effect such Designated Foreign Filing. 
 Regardless of which Party is responsible for preparation, prosecution and maintenance of a Joint Invention Patent, the Parties shall share equally all reasonable, documented costs and expenses incurred in
connection with procuring Joint Invention Patents (including entering national phase in all agreed countries), including application preparation, filing fees, prosecution, maintenance and all costs associated with reexamination, oppositions and
interference proceedings. The filing Party shall invoice the other Party for such costs and expenses, and the other Party will pay such invoices within thirty (30) days after receipt. 

7.5 Cooperation. The Parties agree to cooperate in the preparation and prosecution of all Joint Invention Patent applications
filed under Section 7.3, including obtaining and executing necessary powers of attorney and assignments by the named inventors, providing relevant technical reports to the filing Party concerning the Other Joint Invention disclosed in such
Joint Invention Patent applications, obtaining execution of such other documents which will be needed in the filing and prosecution of such Joint Invention Patent applications, and, as requested, updating each other regarding the status of such
Joint Invention Patent applications. The Parties will reasonably cooperate to obtain any export licenses that might be required for such activities. 
 7.6 Disclosure. Each party shall make available to the other party in confidence all information in its possession necessary or expedient for the filing of Patents arising out of such
party’s performance under this Agreement in all countries of the world. 
 7.7 Infringement. If in the
opinion of either Party any issued Patent contained in the Optimer Patents has been infringed by a Third Party, such Party shall give to the other Party prompt written notice of such alleged infringement. 

(a) Optimer Patents. With respect to any alleged infringement of any Optimer Patents with respect to the rights granted to
Cempra under this Agreement, Cempra shall have the first and primary right, but not the obligation, to, in its sole discretion, to initiate, prosecute, and control any action or legal proceedings, and/or enter into a settlement, including any
declaratory judgment action, on its behalf or in Optimer’s name, if necessary, with respect to such alleged infringement. 

If, within [*] months of the notice above, Cempra (i) shall have been unsuccessful in persuading the alleged infringer
to desist, (ii) shall not have brought and shall not be diligently prosecuting an infringement action, or (iii) has not entered into settlement discussions with respect to such infringement, or if Cempra notifies Optimer that it has
decided not to undertake any of the foregoing against any such alleged infringer, then Optimer shall then have the right to bring suit to enforce such Optimer Patents at its own expense. In any such litigation brought by Cempra, Cempra shall have
the right to use and sue in Optimer’s name, and Optimer shall cooperate reasonably, as requested by Cempra and at Cempra’s expense (which expense shall be reasonable). 

(b) Cempra Patents. With respect to any alleged infringement of any Cempra Patents with respect to the rights granted to
Optimer under this Agreement, Optimer shall have the first and primary right, but not the obligation, to, in its sole discretion, to initiate, prosecute, and control any action or legal proceedings, and/or enter into a settlement, including any
declaratory judgment action, on its behalf or in Cempra’s name, if necessary, with respect to such alleged infringement. If, within [*] months of the notice above, Optimer (i) shall have been unsuccessful in persuading the alleged

  
  

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 infringer to desist, (ii) shall not have brought and shall not be diligently prosecuting an
infringement action, or (iii) has not entered into settlement discussions with respect to such infringement, or if Optimer notifies Cempra that it has decided not to undertake any of the foregoing against any such alleged infringer, then Cempra
shall then have the right to bring suit to enforce such Cempra Patents at its own expense. In any such litigation brought by Optimer, Optimer shall have the right to use and sue in Cempra’s name, and Cempra shall cooperate reasonably, as
requested by Optimer and at Optimer’s expense (which expense shall be reasonable). 
 (c) Procedure. The
Party pursuing or controlling any action against an alleged infringer pursuant to the foregoing (the “Controlling Party”) shall be free to enter into a settlement, consent judgment, or other voluntary disposition of any such action,
provided, however, that (i) the Controlling Party shall consult with the other Party (the “Secondary Party”) prior to entering into any settlement thereof and (ii) any settlement, consent judgment or other voluntary
disposition of such actions which (1) materially limits the scope, validity, or enforceability of any Optimer Patents (if Optimer is the Secondary Party) or Patents Controlled by Cempra (if Cempra is the Secondary Party),
(2) subjects the Secondary Party to any non-indemnified liability or obligation, or (3) admits fault or wrongdoing on the part of Secondary Party must be approved in writing by Secondary Party, such approval not to be unreasonably
withheld. Secondary Party shall provide the Controlling Party notice of its approval or denial of such approval within ten (10) business days of any request for such approval by the Controlling Party, provided that (i) in the event
Secondary Party wishes to deny such approval, such notice shall include a written description of Secondary Party’s reasonable objections to the proposed settlement, consent judgment, or other voluntary disposition and (ii) Secondary Party
shall be deemed to have approved such proposed settlement, consent judgment, or other voluntary disposition in the event it fails to provide such notice within such ten (10) business day period. Any recovery or damages received by the
Controlling Party with respect to the infringement of a Party’s rights under this Agreement shall be used first to reimburse the Parties for unreimbursed reasonable, documented expenses incurred in connection with such action, and the remainder
shall be split [*] ([*]%) to Controlling Party and [*] percent ([*]%) to Secondary Party. Notwithstanding the foregoing, the Secondary Party, at its expense, shall have the right to be represented by counsel of its choice in any such
proceeding. 
 7.8 Infringement of Third Party Rights. 

(a) If a claim is brought by a Third Party alleging patent infringement by Cempra, Optimer, their Affiliates, or their
sublicensees with respect to the manufacture, use, sale, offer for sale or importation of Macrolide Antibiotics, Test Products, Cempra Products, or Optimer Products or any third party challenges the validity of any claims of any Optimer Patents or
Cempra Patents, each Party will give prompt written notice to the other Party of such claim. 
 (b) As between the
parties to this Agreement, Cempra shall have the first and primary right at its own expense to defend, control the defense of, and/or settle any such claim against Cempra, its Affiliates, or its sublicensees in the Territory, using counsel of its
own choice. Cempra shall be free to enter into a settlement, consent judgment, or other voluntary disposition of such action, provided that any settlement, consent judgment or other voluntary disposition of such actions which (i) materially
limits the scope, validity, or enforceability of patents included in the Optimer Patents, (ii) subjects Optimer to any nonindemnified liability, or (ii) admits fault or wrongdoing on the part of Optimer must be approved in writing by
Cempra, such approval not being unreasonably withheld. Optimer shall provide Cempra notice of such approval or denial of such approval within ten (10) business days of any request for such approval by Cempra, provided that (i) in the event
Optimer wishes to deny such approval, such notice shall include a written description of Optimer’s reasonable objections to the 
  

 

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 28 

 
proposed settlement, consent judgment, or other voluntary disposition and (ii) Optimer shall be deemed to have approved of such proposed settlement, consent judgment, or other voluntary
disposition in the event it fails to provide such notice within such ten (10) business day period. Optimer agrees to cooperate with Cempra in any reasonable manner deemed by Cempra to be necessary in defending any such action. Cempra shall
reimburse Optimer for any out of pocket expenses incurred in providing such assistance. Any recovery or damages received by Cempra in any action or settlement under this Section 7.7(b) with respect to the rights licensed to Cempra under
this Agreement shall be used first to reimburse the Parties for unreimbursed reasonable, documented expenses incurred in connection with such action, and the remainder shall be split [*] percent ([*]%) to Cempra and [*] percent ([*]%) to Optimer.
Notwithstanding the foregoing, either Party, at its expense, shall have the right to be represented by counsel of its choice in any such proceeding controlled by the other Party. 

(c) As between the parties to this Agreement, Optimer shall have the first and primary right at its own expense to defend, control
the defense of, and/or settle any such claim against Optimer, its Affiliates, or its sublicensees in any ASEAN Countries, using counsel of its own choice. Optimer shall be free to enter into a settlement, consent judgment, or other voluntary
disposition of such action with respect to any ASEAN Countries, provided that any settlement, consent judgment or other voluntary disposition of such actions which (i) materially limits the scope, validity, or enforceability of any Patents
owned or Controlled by Cempra, (ii) subjects Cempra to any nonindemnified liability, or (ii) admits fault or wrongdoing on the part of Cempra must be approved in writing by Cempra, such approval not being unreasonably withheld. Cempra
shall provide Optimer notice of such approval or denial of such approval within ten (10) business days of any request for such approval by Optimer, provided that (i) in the event Cempra wishes to deny such approval, such notice shall
include a written description of Cempra’s reasonable objections to the proposed settlement, consent judgment, or other voluntary disposition and (ii) Cempra shall be deemed to have approved of such proposed settlement, consent judgment, or
other voluntary disposition in the event it fails to provide such notice within such ten (10) business day period. Cempra agrees to cooperate with Optimer in any reasonable manner deemed by Optimer to be necessary in defending any such action.
Optimer shall reimburse Cempra for any out of pocket expenses incurred in providing such assistance. Any recovery or damages received by Optimer in any action or settlement under this Section 7.7(c) with respect to the rights licensed to
Optimer under this Agreement shall be used first to reimburse the Parties for unreimbursed reasonable, documented expenses incurred in connection with such action, and the remainder shall be split [*] percent ([*]%) to Optimer and [*] percent
([*]%) to Cempra. Notwithstanding the foregoing, either Party, at its expense, shall have the right to be represented by counsel of its choice in any such proceeding controlled by the other Party. 

7.9 Reimbursement. Each Party shall invoice the other Party for any reasonable, documented costs incurred that are to be
borne by the other Party pursuant to this Article 7. Each Party shall pay the other Party such amounts within thirty (30) days of its receipt of any such invoice. 

7.10 Trademarks. Cempra may, in its sole discretion, select trademarks for Cempra Products and shall own all such trademarks
world-wide. To the extent Cempra pursues trademarks for Cempra Products, as between the parties, Cempra shall have the sole responsibility for the filing, prosecution and maintenance of registrations of product trademarks for Cempra Products, at its
sole expense. Optimer shall not have any rights to any trademarks of Cempra under this Agreement; provided that, if it is commercially reasonable to do so, Cempra shall, at Optimer’s request, license such trademarks under a separate agreement
to Optimer for use in the ASEAN Countries. Optimer may, in its sole discretion, select trademarks for Optimer Products and shall own all such trademarks world-wide. To the extent Optimer pursues trademarks for Optimer Products, as between the
parties, Optimer shall have the sole 
  
  

	[*]	Confidential treatment requested; certain information omitted and filed separately with the SEC. 

  
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 responsibility for the filing, prosecution and maintenance of registrations of product trademarks for
Optimer Products, at its sole expense. Cempra shall not have any rights to any trademarks of Optimer under this Agreement; provided that, if it commercially reasonable to do so, Optimer shall, at Cempra’s request, license such trademarks under
a separate agreement to Cempra for use in the Territory. 
 8. CONFIDENTIALITY 

8.1 Treatment of Confidential Information. The Parties agree that during the Term, and for a period of five (5) years
after the end of the Term, a Party receiving Confidential Information of the other Party will (a) maintain in confidence such Confidential Information to the same extent such Party maintains its own proprietary industrial information of similar
kind and value (but at a minimum each Party shall use commercially reasonable efforts), (b) not disclose such Confidential Information to any Third Party without prior consent of the other Party, and (c) not use such Confidential
Information for any purpose except those permitted by this Agreement. 
 8.2 Exceptions. A Party shall not have
the obligations set forth in Section 8.1 with respect to any portion of such Confidential Information that it can show by adequate documentation: 
 (a) is publicly disclosed by the disclosing Party, either before or after it becomes known to the receiving Party; 
 (b) was known to the receiving Party, without obligation to keep it confidential, prior to when it was received from the disclosing Party, as demonstrated by receiving Party’s written records;

 (c) is subsequently disclosed to the receiving Party without obligation of confidentiality or limitation on use by a
Third Party lawfully in possession thereof without obligation to keep it confidential; 
 (d) has been published by a
Third Party; or 
 (e) has been independently developed by the receiving Party without the aid, application or use of
Confidential Information. 
 8.3 Authorized Disclosure. Notwithstanding Section 8.1, a Party may disclose
Confidential Information belonging to the other Party to the extent such disclosure is necessary in the following instances: 

(a) filing or prosecuting Patents pursuant to Article 7; 

(b) Regulatory Filings; 
 (c) prosecuting or defending litigation relating to Macrolide Antibiotics, Test Products or Products; 
 (d) complying with applicable laws and governmental regulations; and 

(e) disclosure, in connection with the performance of this Agreement or exercise of the licenses or rights conveyed herein, to
Affiliates, licensees, sublicensees, employees, consultants, or agents of either Party, each of whom prior to disclosure must be bound by substantially similar obligations of confidentiality and non-use at least equivalent in scope to those set
forth in this Article 8. 

  
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 8.4 Terms of the Agreement. The Parties acknowledge that the terms of this
Agreement shall be treated as Confidential Information of both Parties. Such terms may be disclosed by a Party to individuals or entities covered by 8.3(e) above, each of whom prior to disclosure must be bound by similar obligations of
confidentiality and non-use at least equivalent in scope to those set forth in this Article 8. Disclosure of the terms of this Agreement (but not other Confidential Information received from the other Party) may also be made, under
obligations of confidentiality and non use at least equivalent in scope to those set forth in this Article 8, to actual or potential bankers, lenders, investors, acquirors, acquisition targets, and strategic partners of either Party.

 8.5 Publicity. The public announcement of the execution of this Agreement is set forth on
Schedule 8.5 hereto. Each Party shall be entitled, in its sole discretion, to make public announcements regarding its Development and Commercialization of Products, subject to the other Party’s opportunity to review and comment with
respect thereto provided below. In addition, either Party may make a public statement, including in analyst meetings, concerning the Agreement or the progress of the Test Products or Products where such statement is required by law, applicable stock
exchange regulation or legal proceedings. In connection with any filing described in the foregoing sentence, such Party shall use commercially reasonable efforts to obtain confidential treatment of economic and trade secret information. In any
event, the Parties agree to take all reasonable action to avoid disclosure of Confidential Information except as permitted hereunder, and shall cooperate with each other with respect to all such disclosures. The Party that is required to or has
otherwise decided to make a public statement pursuant permitted under this Section 8.5 will give the other Party reasonable advance notice of the text of any proposed statement so that the other Party will have the opportunity to comment upon
the statement. Either Party may disclose any matter that has previously been publicly disclosed in accordance with this Section 8.5. Except as described above, neither Party will make any public announcement regarding the terms of or events
related to the Agreement without the prior consent of the other Party. 
 8.6 Publications. Neither Optimer nor
its employees, contractors or investigators shall publish or present any information, including without limitation the results of the Research Program or preclinical or clinical studies, with respect to any Macrolide Antibiotic, Test Product or
Cempra Product without Cempra’s prior consent (which may be withheld in Cempra’s sole and final discretion), except as permitted under Section 8.3(d) or this Section 8.6. Optimer agrees to provide Cempra a copy of any
such proposed publication or presentation at least 60 days prior to its submission for publication, and Cempra shall have 60 days in which to review the proposed publication or presentation for the purposes described below. Cempra may
request in writing, and the Optimer shall agree to, (i) the deletion of any of Cempra’s Confidential Information, (ii) any reasonable changes requested by Cempra, consistent with scientific practice, or (iii) a delay of such
proposed submission for an additional period, not to exceed ninety (90) days, in order to protect the potential patentability of any technology described therein. Cempra, at its election, shall be entitled to receive in any such publication an
acknowledgment of its support of and involvement in the Research Program and its rights to Optimer Technology. 
 9. TERM AND TERMINATION

 9.1 Term. This Agreement shall become effective on the Effective Date and shall continue on a
Product-by-Product (Cempra Product or Optimer Product, as applicable) and country-by-country basis until the earlier of (1) the expiration of the Royalty Term with respect to the applicable Product (Cempra Product or Optimer Product, as
applicable) in the applicable country; or (2) the effective date of termination pursuant to Section 9.2 or 9.3 (the “Term”). Upon expiration of this Agreement pursuant to clause (1) above with respect to a
particular Product in a particular country, the Parties and their Affiliates shall have the perpetual, unrestricted, fully-paid, royalty-free world-wide right, with rights of sublicense, to make, use, sell, offer for sale, and import such Product in
such country. 

  
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 9.2 Termination by Cempra or Optimer. Cempra may terminate this Agreement at any
time upon thirty (30) days prior written notice to Optimer. At any time following the end of the Research Term, Optimer may terminate this Agreement upon thirty (30) days prior written notice to Cempra. In either case, the effects of such
termination shall be as further described in Section 9.4 below. 
 9.3 Mutual Termination Rights. Either
Party will have the right to terminate this Agreement upon the following: 
 (a) It believes that the other Party is
in material breach of this Agreement, in which case the non-breaching Party may deliver written notice of such material breach to the other Party, such notice to describe in detail the nature of such breach. The allegedly breaching Party shall have
[*] days from receipt of such notice to cure such breach. Any such termination shall become effective at the end of such [*] period unless the breaching Party has cured any such breach or default prior to the expiration of such [*]
period (or, if such default is capable of being cured but cannot be cured within such [*]-day period, the breaching Party has commenced and diligently continued actions to cure such default provided always that, in such instance, such cure must have
occurred within [*] days after notice thereof was provided to the breaching Party by the non-breaching Party to remedy such default); or 
 (b) the other Party is generally unable to meet its debts when due, or makes a general assignment for the benefit of its creditors, or there shall have been appointed a receiver, trustee or other
custodian for such Party for or a substantial part of its assets, or any case or proceeding shall have been commenced or other action taken by or against such Party in bankruptcy or seeking the reorganization, liquidation, dissolution or winding-up
of such Party or any other relief under any bankruptcy, insolvency, reorganization or other similar act or law, and any such event shall have continued for sixty (60) days undismissed, unstayed, unbonded and undischarged. In such circumstances,
the other Party may, upon notice to such Party, terminate this Agreement, such termination to be effective upon such Party’s receipt of such notice. 
 9.4 Effects of Termination. 
 (a) Except as set forth in
Sections 9.1, 9.4(b), 9.4(c), and 9.4(d), upon any termination of this Agreement, all licenses granted under this Agreement shall terminate, Cempra and its Affiliates shall cease Development and Commercialization of all Macrolide Antibiotics,
Test Products and Cempra Products, and Optimer and its Affiliates shall cease development and/or commercialization of Optimer Products, provided that, notwithstanding the foregoing, each Party and its Affiliates shall have the privilege, subject to
the payment of royalties as required under Section 6, of (i) completing the manufacture of any Products in the process of manufacture as of the effective date of such termination (the “Termination Date”), (ii) selling
such Products and all finished Products in their possession or under their control as of the Termination Date for a period of one year following the Termination Date upon commercially reasonable conditions, and (iii) completing performance of
all contracts entered into with third parties prior to the Termination Date (1) for the marketing, sale, or manufacture of Products or (2) requiring the use of Products or technology claimed in the Optimer Patents or Cempra Patents, as
applicable, for a period of one year following the Termination Date. Notwithstanding any provision herein to the contrary, no termination of this Agreement by either Party shall be construed as a termination of any valid sublicense granted by the
other Party, its Affiliates, or its sublicensees with respect to the rights granted under this Agreement. Upon termination of this Agreement by a Party each sublicense of rights granted to a Third Party by the other Party shall, to the extent not
imposing obligations on the other Party in excess of those contained herein, be automatically assigned to such Party. 
  

 

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 (b) If a Party terminates this Agreement in accordance with Section 9.2, then,
at the other Party’s express election upon notice of termination, all licenses granted by the terminating Party to the non-terminating Party shall survive, in which event, the non-terminating Party’s obligations set forth in Article 4
and in Article 6 (including without limitation the obligation to pay to the terminating Party any milestone and/or royalty payments set forth in Article 6 and provide the reports set forth therein), the non-terminating
Party’s rights under Section 7, and all other provisions of this Agreement applicable to the foregoing, other than Sections 1A, 2, and 3 (which shall terminate), shall survive. It is understood and agreed that following such a
termination, the terminating Party shall retain the right to terminate the other Party’s remaining licenses and rights in accordance with Section 9.3, and the non-terminating Party shall retain the right to subsequently terminate its
remaining licenses and rights under this Agreement pursuant to Section 9.2, in which event the applicable provisions of Section 9.4(a) shall apply. 
 (c) If Cempra terminates this Agreement in accordance with Section 9.3, then at Cempra’s express election upon notice of termination, all licenses and rights granted by Optimer to Cempra
shall survive, in which event Cempra’s obligations set forth in Article 4 and in Article 6 (including without limitation the obligation to pay to Optimer the royalty and milestone payments set forth in Article 6
and provide the reports set forth therein), Cempra’s rights under Section 7, and all other provisions of this Agreement applicable to the foregoing, other than Sections 1A, 2, and 3 (which shall terminate), shall survive. It is
understood and agreed that following such a termination, Optimer shall retain the right to terminate the remaining licenses and rights of Cempra in accordance with Section 9.3, and Cempra shall retain the right to subsequently terminate its
remaining licenses and rights under this Agreement pursuant to Section 9.2, in which event the applicable provisions of Section 9.4(a) shall apply. 
 (d) If Optimer terminates this Agreement in accordance with Section 9.3, then at Optimer’s express election upon notice of termination, all licenses and rights granted by Cempra to
Optimer shall survive, in which event Optimer’s obligations set forth in Article 4 and in Article 6 (including without limitation obligation to pay to Cempra the royalty and milestone payments set forth in Article 6
and provide the reports set forth therein), Optimer’s rights under Article 7, and all other provisions of this Agreement applicable to the foregoing, other than Sections 1A, 2, and 3 (which shall terminate), shall survive. It is
understood and agreed that following such a termination, Cempra shall retain the right to terminate the remaining licenses and rights of Optimer in accordance with Section 9.3, and Optimer shall retain the right to subsequently terminate its
remaining licenses and rights under this Agreement pursuant to Section 9.2, in which event the applicable provisions of Section 9.4(b) shall apply. 
 (e) Termination of this Agreement shall not terminate the obligations of a Party to make any payments then owing through the date of termination or the obligations of confidentiality imposed on
either Party. 
 (f) The remedies set forth in this Article 9 are not exclusive, and shall not limit any other
legal or equitable remedies that are available to the parties. 
 9.5 Survival. The following provisions shall
survive any expiration or termination of this Agreement: Sections 5.6, 6.15, 7, 8, 9, 10, 11, 12 and 13, together with any sections referenced in such surviving provisions or necessary to give them effect. 

10. REPRESENTATIONS AND WARRANTIES 
 10.1 General Representations and Warranties. Each Party represents and warrants to the other that, as of the date hereof: 

  
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 (a) it is duly organized and validly existing under the laws of its state or country
of incorporation, and has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof; 
 (b) it is duly authorized to execute and deliver this Agreement and to perform its obligations hereunder, and the person or persons executing this Agreement on its behalf has been duly authorized
to do so by all requisite corporate action; 
 (c) this Agreement is legally binding upon it and enforceable in
accordance with its terms. The execution, delivery and performance of this Agreement by it does not conflict with any agreement, instrument or understanding, oral or written, to which it is a party or by which it may be bound, nor violate any
material law or regulation of any Governmental Authority having jurisdiction over it; 
 (d) it is aware of no
action, suit or inquiry or investigation instituted by any governmental agency that questions or threatens the validity of this Agreement; 
 (e) all necessary consents, approvals and authorizations of all governmental authorities and other Persons required to be obtained by such Party to enter into, or perform its obligations under,
this Agreement have been obtained (provided, however, that the foregoing shall not be construed as a representation or warranty concerning governmental authorizations and non-infringement of intellectual property rights of Third Parties disclaimed
in Section 10.3 below). 
 (f) it has not granted, and will not grant during the Term of the Agreement, any
right to any Third Party that would conflict with the rights granted to the other Party hereunder. It has (or will have at the time the performance is due) maintained and will maintain and keep in full force and effect all agreements necessary
to perform its obligations hereunder; 
 (g) all products, materials and Information created by the Parties under this
Agreement is current and accurate, is such Party’s original work (except for identified third-party materials), and, to such Party’s knowledge, will not infringe upon, violate or misappropriate any intellectual property right of any third
party; and 
 (h) to the extent any third-party materials are incorporated in the products, such Party has obtained
from such third party rights (if any) reasonably sufficient to enable the such Party to comply with this Agreement. 

10.2 Optimer Representations and Warranties. Optimer represents, warrants, and covenants that: 

(a) Optimer has not, and during the term of the Agreement will not, grant any right to any Third Party relating to Optimer
Technology which conflicts with the rights granted to Cempra hereunder; 
 (b) During the Term, Optimer will not, without
the prior written consent of Cempra, encumber the Optimer Patents or Optimer Know-How, respectively, with liens, mortgages, security interests or another similar interest that would give the holder the right to convert the interest into ownership,
unless the encumbrance is expressly subject to the licenses herein; 
 (c) Optimer has (or will have at the time
performance is due) maintained and will maintain and keep in full force and effect all agreements necessary to perform its obligations hereunder; 

  
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 (d) Optimer does not have any present knowledge from which it would reasonably
conclude that the Optimer Patents are invalid or that their exercise would infringe patent rights of any Third Party; 

(e) The Optimer Patents listed on Schedule 1.30 are, as of the Effective Date, the only patents or patent applications
owned, controlled, or licensed by Optimer claiming Macrolide Antibiotics, Test Products, Cempra Products, Optimer Technology, or the manufacture, use or application of any of the foregoing. 

(f) To the best of Optimer’s knowledge, each item included in the Optimer Patents that is registered, filed or issued under
the authority of an appropriate governmental authority is and at all times has been in compliance with all legal requirements applicable thereto, and all filings, payments, and other actions required to be made or taken to maintain such item of
Optimer Patents in full force and effect have been made by the applicable deadline. Furthermore, (1) no patent application or patent included in the Optimer Patents has been abandoned or allowed to lapse and (2) no provisional patent
application included therein has expired without the filing of a nonprovisional patent application that claims the benefit of such provisional patent application. 
 (g) Optimer has, to the knowledge of Optimer’s executive management, furnished to Cempra all tangible manifestations of the Optimer Technology which Optimer owns or possesses as of the
Effective Date; 
 (h) Optimer has taken commercially reasonable measures, using its good faith business judgment,
to protect the confidentiality of the Optimer Know How; 
 (i) None of the Optimer Patents is the subject of any
pending interference, opposition, cancellation or other protest proceeding; 
 (j) Optimer has no knowledge of any claim
pending, threatened, or previously made alleging infringement or misappropriation of any patent, trade secret, or other intellectual property right of any Third Party relative to the Optimer Patents, the technology claimed therein, Optimer Know How,
Test Products, Macrolide Antibiotics, or Cempra Products; and 
 (k) Optimer is not aware of any third party
activities which would constitute misappropriation or infringement of the Optimer Technology (including but not limited to Optimer Patents); 
 (l) Optimer owns all right, title, and interest to all Optimer Technology, free and clear of any liens, claims, and encumbrances of any party, and none of the Optimer Technology has been obtained
by Optimer pursuant to any license or other agreement with any third party; 
 (m) Optimer does not presently own or
Control any rights to any trademarks, service marks, trade dress, or similar intellectual property rights with respect to Cempra Products or Macrolide Antibiotics. 
 10.3 Cempra Representations and Warranties. Optimer represents, warrants, and covenants that: 
 (a) Cempra has not, and during the term of the Agreement will not, grant any right to any Third Party relating to Cempra Patent, Cempra Product, or Cempra Know-How which conflicts with the rights
granted to Optimer hereunder; 

  
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 (b) During the Term, Cempra will not, without the prior written consent of Optimer,
encumber the Cempra Patents or Cempra Know-How, respectively, with liens, mortgages, security interests or another similar interest that would give the holder the right to convert the interest into ownership, unless the encumbrance is expressly
subject to the licenses herein; and 
 (c) Cempra has (or will have at the time performance is due) maintained
and will maintain and keep in full force and effect all agreements necessary to perform its obligations hereunder. 
 10.4
Disclaimer Concerning Technology. EACH PARTY EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, EXCEPT FOR THOSE SET FORTH IN THIS AGREEMENT, INCLUDING WITHOUT LIMITATION THE WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. NOTWITHSTANDING ANYTHING TO THE CONTRARY IN THIS AGREEMENT, (A) BOTH PARTIES ACKNOWLEDGE AND AGREE THAT THE ACTIVITIES TO BE CONDUCTED UNDER THE RESEARCH PROGRAM ARE INHERENTLY UNCERTAIN AND, PROVIDED THAT EACH
PARTY ENGAGES IN DILIGENT EFFORTS TO PERFORM ITS OBLIGATIONS HEREUNDER, THAT THERE ARE OTHERWISE NO ASSURANCES THAT THE PARTIES WILL SUCCESSFULLY SYNTHESIZE MACROLIDE ANTIBIOTICS MEETING THE SPECIFICATIONS SET FORTH BY CEMPRA AND OPTIMER
JOINTLY OR IDENTIFY A TEST PRODUCT, OR SUCCESSFULLY CONDUCT OTHER ACTIVITIES CONTEMPLATED TO BE PERFORMED IN THE RESEARCH PROGRAM, OR THAT ANY MACROLIDE ANTIBIOTICS OR TEST PRODUCT WILL BE SUCCESSFULLY DEVELOPED AND COMMERCIALIZED BY CEMPRA AS A
LICENSED PRODUCT, OR THAT REQUIRED GOVERNMENTAL APPROVALS IN CONNECTION WITH THE MANUFACTURE, CLINICAL DEVELOPMENT AND/OR COMMERCIALIZATION OF MACROLIDE ANTIBIOTICS, TEST PRODUCTS AND/OR LICENSED PRODUCTS CAN OR WILL BE OBTAINED; AND (B) EACH
PARTY EXPRESSLY DISCLAIMS ANY REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, TO THE CONTRARY. 
 11. INDEMNITIES 

11.1 Mutual Indemnification. Subject to Section 11.2, each Party hereby agrees to indemnify, defend and hold the other
Party, its Affiliates, its licensees, and its and their officers, directors, employees, consultants, contractors, sublicensees and agents (collectively, “Representatives”) harmless from and against any and all damages or other
amounts payable to a Third Party claimant, as well as any reasonable attorneys’ fees and costs of litigation arising out of any such Claim (as defined in this Section 11.1), (collectively, “Damages”) resulting from
claims, suits, proceedings or causes of action (“Claims”) brought by a Third Party against a Party or its Representatives based on: (a) material breach by the indemnifying Party of this Agreement, (b) breach of any
applicable law, rule, or regulation by such indemnifying Party in connection with the performance of its obligations hereunder or the exercise of licenses or rights conveyed hereunder, (c) gross negligence or willful misconduct by such
indemnifying Party, its Affiliates, or their respective employees, contractors or agents, (d) the indemnifying Party’s Development, Commercialization, manufacture, use or sale of Macrolide Antibiotics, Test Products, or Products, except,
in each case, to the extent such Damages are subject to indemnification by the other Party under this Section 11.1. 

11.2 Notification. In the event that any Third Party asserts a claim with respect to any matter for which a Party (the
“Indemnified Party”) is entitled to indemnification hereunder (a “Third Party Claim”), then the Indemnified Party shall promptly notify the Party obligated to indemnify the Indemnified Party (the
“Indemnifying Party”) thereof; provided, however, that no delay on the part of the Indemnified Party in notifying the Indemnifying Party shall relieve the Indemnifying Party from any obligation hereunder unless (and then only
to the extent that) the Indemnifying Party is prejudiced 

  
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thereby. Indemnifying Party may assume the complete control of the defense, compromise or settlement of any Third Party Claim (provided that any settlement of any Third Party Claim that
(i) subjects Indemnified Party to any non-indemnified liability or (ii) admits fault or wrongdoing on the part of Indemnified Party will require the prior written consent of such Indemnified Party, provided such consent will not be
unreasonably withheld), including, at its own expense, employment of legal counsel, and at any time thereafter Indemnifying Party will be entitled to exercise, on behalf of Indemnified Party, any rights which may mitigate the extent or amount of
such Third Party Claim; provided, however, that if Indemnifying Party has exercised its right to assume control of such Third Party Claim, Indemnified Party (i) may, in its sole discretion and at its own expense, employ legal
counsel to represent it (in addition to the legal counsel employed by Indemnifying Party) in any such matter, and in such event legal counsel selected by Indemnified Party will be required to reasonably confer and cooperate with such counsel of
Indemnifying Party in such defense, compromise or settlement for the purpose of informing and sharing information with Indemnifying Party; (ii) will, at Indemnifying Party’s own expense, make available to Indemnifying Party those
employees, officers, contractors, and directors of Indemnified Party whose assistance, testimony or presence is necessary or appropriate to assist Indemnifying Party in evaluating and in defending any such Third Party Claim; provided,
however, that any such access will be conducted in such a manner as not to interfere unreasonably with the operations of the businesses of Indemnified Party; and (iii) will otherwise fully cooperate with Indemnifying Party and its legal
counsel in the investigation and defense of such Third Party Claim. 
 11.3 Exclusion of Damages. IN NO EVENT
SHALL EITHER PARTY OR ITS AFFILIATES BE LIABLE TO THE OTHER PARTY FOR ANY INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE, EXEMPLARY OR CONSEQUENTIAL DAMAGES, WHETHER BASED UPON A CLAIM OR ACTION OF CONTRACT, WARRANTY, NEGLIGENCE, STRICT LIABILITY OR OTHER
TORT, OR OTHERWISE, ARISING OUT OF THIS AGREEMENT, UNLESS SUCH DAMAGES ARE DUE TO THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF THE LIABLE PARTY. NOTWITHSTANDING ANYTHING TO THE CONTRARY, THE FOREGOING SHALL NOT BE CONSTRUED TO LIMIT THE INDEMNITY
OBLIGATIONS SET FORTH IN SECTION 11.1 ABOVE OR EITHER PARTY’S LIABILITY FOR PATENT INFRINGEMENT OR BREACH OF SECTIONS 8 (CONFIDENTIALITY), 7 (INTELLECTUAL PROPERTY), 5.1 (WITH RESPECT TO CEMPRA’S BREACH THEREOF), OR 5.4 (WITH
RESPECT TO OPTIMER’S BREACH THEREOF). 
 12. DISPUTE RESOLUTION 

12.1 Disputes. The Parties recognize that disputes as to certain matters may from time to time arise during the Term that
relate to either Party’s rights and/or obligations hereunder. It is the objective of the Parties to facilitate the resolution of disputes arising under this Agreement in an expedient manner by mutual cooperation and without resort to litigation
or arbitration. To accomplish this objective, the Parties agree that, in the event of any disputes, controversies or differences that may arise between the Parties, out of or in relation to or in connection with this Agreement, or for the breach
thereof, upon the request of either Party, the Parties agree to meet and discuss in good faith a possible resolution thereof. If the matter is not resolved within thirty (30) days following the request for discussions, either Party may refer
the matter to arbitration in accordance with Section 12.3 below. Notwithstanding the foregoing, each Party shall be entitled to seek appropriate injunctive relief in any court of competent jurisdiction (i) to preserve such Party’s
rights pending resolution of arbitration proceedings under this Agreement, (ii) to avoid irreparable damages, or (iii) with respect to any matters concerning intellectual property rights or confidentiality. 

12.2 Governing Law. Resolution of all disputes arising out of or related to this Agreement or the performance, enforcement,
breach or termination of this Agreement and any remedies relating thereto, 

  
 37 

 
shall be governed by and construed under the substantive laws of the State of California, without regard to conflicts of law rules that would provide for application of the law of a
jurisdiction outside California. 
 12.3 Arbitration. Except as otherwise expressly provided herein, the Parties
agree that any dispute not resolved internally by the Parties, within thirty (30) days after meeting pursuant to Section 12.1, shall be finally resolved, upon notice to the other Party by either Party, by binding arbitration in accordance
with the provisions of this Section 12.3. The arbitration shall be conducted by the Judicial Arbitration and Mediation services, Inc. (“JAMS”) under its rules of arbitration then in effect, except as modified in this
Agreement. Each Party shall select one (1) independent, neutral arbitrator experienced in the biotechnology/pharmaceutical industry, and the two (2) arbitrators so selected shall choose a third independent, neutral arbitrator experienced
in the biotechnology/pharmaceutical industry. In the event a Party fails to select its such arbitrator within fifteen (15) business days of its receipt of the notice provided above, the other Party shall be entitled to select such arbitrator.
The arbitrators shall use their best efforts to rule on each disputed issue within sixty (60) calendar days after completion of hearings on the matter(s) in dispute, and the arbitration decision(s) shall be rendered in writing to
the Parties and must specify the basis(es) on which the decision(s) was(were) made. Such decision(s) shall be binding and not be appealable to any court in any jurisdiction. Unless otherwise mutually agreed upon by the Parties, the
arbitration proceedings shall be conducted in New York, New York. One or more of the Parties to any arbitration proceeding commenced under this Agreement shall be entitled, as a part of the arbitration award, to the costs and expenses
(including reasonable attorneys fees and interest on any award) of investigating, preparing and pursuing an arbitration claim to the extent that the arbitrators award such costs and expenses, provided that, notwithstanding the foregoing, the Parties
shall bear the costs and expenses incurred in connection with an arbitration under this section in inverse proportion to the award granted to each of them by the arbitrators. 
 13. MISCELLANEOUS 
 13.1 Entire Agreement; Amendment. This
Agreement, including the exhibits attached hereto, sets forth the complete, final and exclusive agreement and all the covenants, promises, agreements, warranties, representations, conditions and understandings between the Parties hereto and
supersedes and terminates all prior agreements and understandings between the Parties, including the Letter Agreement. There are no covenants, promises, agreements, warranties, representations, conditions or understandings, either oral or written,
between the Parties other than as are set forth herein and therein. No subsequent alteration, amendment, change or addition to this Agreement shall be binding upon the Parties unless reduced to writing and signed by an authorized officer of
each Party. 
 13.2 Force Majeure. Both Parties shall be excused from the performance of their obligations
under this Agreement to the extent that such performance is prevented by force majeure and the nonperforming Party promptly provides notice of the prevention to the other Party. Such excuse shall be continued so long as the condition constituting
force majeure continues and the nonperforming Party takes reasonable efforts to remove the condition. For purposes of this Agreement, force majeure shall include conditions beyond the control of the Parties, including without limitation, an act of
God, voluntary or involuntary compliance with any regulation, law or order of any government, war, civil commotion, labor strike or lock-out, epidemic, failure or default of public utilities or common carriers, destruction of production facilities
or materials by fire, earthquake, storm or like catastrophe; provided, however, the payment of invoices due and owing hereunder shall not be delayed by the payer because of a force majeure affecting the payer, unless such force majeure
specifically precludes the payment process. 
 13.3 Notices. Any notices, approvals, or consents required or
permitted to be given under this Agreement shall be in writing, shall specifically refer to this Agreement and shall be deemed to have been sufficiently given for all purposes if mailed by first class certified or registered mail, postage prepaid,
or 

  
 38 

 
by internationally recognized express delivery service or personally delivered. Unless otherwise specified in writing, the mailing addresses of the Parties shall be as described below:

  

			
	 For Optimer:
	  	 Optimer Pharmaceuticals, Inc.
 10110 Sorrento Valley Rd., Suite C
 San Diego, CA 92121

FEIN: 33-0830300
 Fax:
(858) 909-0737
 Attention: Michael N. Chang, President/CEO

		
	 For Cempra:
	  	 Cempra Pharmaceuticals Inc.
 170 Southport Drive, Suite 500
 Morrisville, NC 27560

Fax: (919) 467-1716
 Attention:
Dr. Prabha Fenandes, President/CEO

 13.4 United States Dollars. References in this Agreement to “Dollars” or
“$” shall mean the legal tender of the United States of America. 
 13.5 No Strict
Construction. This Agreement has been prepared jointly and shall not be strictly construed against either Party. 

13.6 Assignment. Neither Party may assign or transfer this Agreement or any rights or obligations hereunder without the prior
consent of the other; provided, however, that a Party may make such an assignment without the other Party’s consent (a) to an Affiliate or in conjunction with a merger, acquisition, or sale of all or substantially all of the
business or assets of such Party to which this Agreement pertains, or (b) if such Party or its Affiliates is required to, or reasonably believes that it will be required to, divest any Product or a competing product in order to comply with law
or the order of any Governmental Authority as a result of a merger or acquisition. This Agreement shall be binding upon and inure to the benefit of the successors and permitted assigns of the Parties. Any assignment or attempted assignment by either
Party in violation of the terms of this Section 13.6 shall be null and void and of no legal effect. 
 13.7
Counterparts. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. 

13.8 Further Actions. Each Party agrees to execute, acknowledge and deliver such further instruments (including without
limitation patent assignments), and to do all such other acts, as may be necessary or appropriate in order to carry out the purposes and intent of this Agreement. 
 13.9 Severability. If any one or more of the provisions of this Agreement is held to be invalid or unenforceable by any court of competent jurisdiction from which no appeal can be or is taken,
or in arbitration proceedings between the Parties as set forth in Article 12 of this Agreement, the provision shall be considered severed from this Agreement and shall not serve to invalidate any remaining provisions hereof. The Parties shall
make a good faith effort to replace any invalid or unenforceable provision with a valid and enforceable one such that the objectives contemplated by the Parties when entering into this Agreement may be realized. 

13.10 Headings. The headings for each article and section in this Agreement have been inserted for convenience of reference
only and are not intended to limit or expand on the meaning of the language contained in the particular article or section. 

  
 39 

 13.11 No Waiver. Any delay in enforcing a Party’s rights under this
Agreement or any waiver as to a particular default or other matter shall not constitute a waiver of such Party’s rights to the future enforcement of its rights under this Agreement, excepting only as to an express written and signed waiver as
to a particular matter for a particular period of time. 
 REMAINDER OF PAGE INTENTIONALLY LEFT BLANK 

  
 40 

 IN WITNESS WHEREOF, the Parties have executed this Agreement in duplicate originals
by their proper officers as of the date and year first above written. 
  

									
	 CEMPRA PHARMACEUTICALS INC.
	  		  	OPTIMER PHARMACEUTICALS, INC.
					
	 BY:
	  	 /s/ Prabhavathi Fernandes
	  		  	BY:	  	 /s/ Michael N. Chang

	 NAME:
	  	Prabhavathi Fernandes	  		  	NAME:	  	Michael N. Chang
	 TITLE:
	  	President and CEO	  		  	TITLE:	  	CFO

  
 41 

 Schedule 1.35 
 Optimer Patents 
 Macrolide Patent Estate 

 

									
	 “Macrolides and Process for Their Preparation”

8024-006-PR
	  	(3/10/2003)	 	Lapsed	  	Provisional	  	 The application has

converted to PCT
 application, 8024-006-WO.

	 “Novel Antibacterial Agents”, 8024-006-WO
	  	WO2004080381/
23-Sep-04
(3/5/2004)	 	Published	  	PCT	  	The application claims composition of matter comprising 14 membered macrolide triazole compounds and/or 14 membered macrolide compounds with novel suger or sugar mimic moieties
at C5 position. The PCT application was published and has entered national phase in US, Europe and Canada.
		  	  
	 	  
	  	  
	  	
					
	 8024-006-US
	  	(9/9/2005)	 	Pending	  	US	  	Notice of Acceptance and Filing Receipt received on 1/12/06. Projected publication date 5/11/06.
		  	  
	 	  
	  	  
	  	
	 8024-006-CA
	  	(12/19/2005)	 	Pending	  	Canada	  	
		  	  
	 	  
	  	  
	  	
	 8024-006-EP
	  	(1/11/2006)	 	Pending	  	Europe	  	
		  	  
	 	  
	  	  
	  	

 Schedule 6.1(1) 

Subscription Agreement 
  

 THE SECURITIES SUBJECT TO THIS SUBSCRIPTION AGREEMENT ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND
RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “1933 ACT”), AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. INVESTORS SHOULD BE
AWARE THAT THEY WILL BE REQUIRED TO BEAR THE FINANCIAL RISKS OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME. 
 NAME OF
PURCHASER: 
 OPTIMER PHARMACEUTICALS INC. 
 CEMPRA PHARMACEUTICALS, INC. 
 SUBSCRIPTION AGREEMENT

 The undersigned (the “Purchaser”) hereby subscribes to and agrees to purchase shares of Common Stock (the
“Shares”) of Cempra Pharmaceuticals, Inc., a Delaware corporation (the “Corporation”). The purchase price hereunder shall be considered paid in full upon the execution by Purchaser of that certain Collaborative Research and
Development and License Agreement dated March 31, 2006 (the “License Agreement”) between the Corporation and Purchaser, with consideration taking the form of the Purchaser’s agreement to perform certain obligations and grant of
various intellectual property rights to the Corporation pursuant to such License Agreement. 
 NOW, THEREFORE, for and in
consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows: 

Section 1. Stock Subscription. The Purchaser hereby subscribes for shares of Corporation Common Stock. The Shares
are being issued as consideration under the License Agreement. 
 Section 2. Representation and Warranties of the
Purchaser. The Purchaser hereby represents, warrants and agrees as follows: 
 (a) The Purchaser is a
resident of the State of California, is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware, and has all the power and authority to enter into, and perform its obligations under this
Subscription Agreement. 
 (b) That the transfer of securities contemplated hereby is made in reliance upon the
Purchaser’s representation to the Corporation, which by its acceptance hereof the Purchaser hereby confirms, that the Shares to be received by it will be acquired for investment for its own account, not as a nominee or agent, and not with a
view to the sale or distribution of any part thereof, and that it has no present intention of selling, granting participation in, or otherwise distributing the same. By executing this Subscription Agreement, the Purchaser further represents that it
does not have any contract, undertaking, agreement, or arrangement with any person to sell, transfer or grant participations to such person, or to any third person, with respect to any of the Shares. 

 (c) The Purchaser understands that the Shares have not been registered under
the 1933 Act on the grounds that the sale provided for in this Agreement and the issuance of securities hereunder is exempt from registration under the 1933 Act, and that the Corporation’s reliance on such exemption is predicated in part on the
Purchaser’s representations set forth herein. The Purchaser realizes that the basis for the exemption may not be present if, notwithstanding such representations, the Purchaser has in mind merely acquiring the Shares for a fixed or determined
period in the future, or for a market rise, or for sale if the market does not rise. The Purchaser does not have any such intention. 
 (d) The Purchaser represents that it is an “Accredited Investor” as such term is defined in Rule 501 or Regulation D promulgated under the Securities Act of 1933, as amended.

 (e) The Purchaser represents that it is experienced in evaluating early-stage companies such as the
Corporation, is able to fend for itself in the transactions contemplated by this Agreement, has such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of its investment, and has the
ability to bear the economic risks of its investment. The Purchaser further represents that it has had access, during the course of the transactions and prior to its acquisition of Shares, to all such information as it deemed necessary or
appropriate (to the extent the Corporation possessed such information or could acquire it without unreasonable effort or expense), and that it has had, during the course of the transactions and prior to its acquisition of Shares, the opportunity to
ask questions of, and receive answers from, the Corporation concerning the terms and conditions of the offering and to obtain additional information (to the extent the Corporation possessed such information or could acquire it without unreasonable
effort or expense) necessary to verify the accuracy of any information furnished to him or to which it had access. 
 (f) The Purchaser understands that the Shares may not be sold, transferred or otherwise disposed of without registration under the 1933 Act or an exemption therefrom, and that in the absence of an
effective registration statement covering the Shares or an available exemption from registration under the 1933 Act, the Shares must be held indefinitely. In particular, the Purchaser is aware that the Shares may not be sold pursuant to
Rule 144 promulgated under the 1933 Act unless all of the conditions of that Rule are met. Among the conditions for use of Rule 144 is the availability of current information to the public about the Corporation. Such information is
not now available and the Corporation has no present plans to make such information available. The Purchaser represents that, in the absence of an effective registration statement covering the Shares it will sell, transfer, or otherwise dispose of
the Shares only in a manner consistent with its representations set forth herein. 
 (g) The Purchaser agrees
that in no event will it make a transfer or disposition of any of the Shares (other than pursuant to an effective registration statement under the 1933 Act or, to the Corporation’s reasonable satisfaction, pursuant to Rule 144), unless and
until (i) the Purchaser shall have notified the Corporation of the proposed disposition and shall have furnished the Corporation with a statement of the circumstances surrounding the disposition, and (ii) if requested by the Corporation,
at the expense of the Purchaser or transferee, it shall have furnished to the Corporation an opinion of counsel, reasonably satisfactory to the Corporation, to the effect that such transfer may be made without registration under the 1933 Act.

 (h) The Purchaser understands that each certificate representing the Shares will be endorsed with a legend
substantially as follows: 

  
 2 

 “THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THESE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO DISTRIBUTION OR RESALE, AND MAY NOT BE SOLD, MORTGAGED, PLEDGED,
HYPOTHECATED OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT FOR SUCH SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND ANY APPLICABLE STATE SECURITIES LAWS, OR THE AVAILABILITY OF AN EXEMPTION FROM THE REGISTRATION
PROVISIONS OF THE SECURITIES ACT OF 1933, AS AMENDED, AND APPLICABLE STATE SECURITIES LAWS.” 
 (i) The
Purchaser understands that no public market now exists for any of the securities issued by the Corporation and that there is no assurance that a public market will ever exist for the Shares. 

Section 3. Indemnity. The Purchaser will indemnify the Corporation, its officers, directors, shareholders,
employees and agents against any losses or damages suffered by any of them as a result of the failure of the above representations and warranties to be true or the failure of the Purchaser to comply with the agreements set forth herein. 

Section 4. Representations and Warranties of the Corporation. The Corporation hereby represents and warrants to the
Purchaser as follows: 
 (a) The Corporation is a corporation duly organized and validly existing under the laws
of the State of Delaware. The Corporation has the requisite corporate power to own and operate its properties and assets, and to carry on its business as currently conducted. 

(b) The Corporation has a requisite legal and corporate power to: (i) execute and deliver this Subscription
Agreement; and (ii) to carry out and perform its obligations under this Subscription Agreement. 
 (c) [The Corporation has no subsidiaries or affiliated companies and does not otherwise own or control, directly or indirectly, any other corporation, association or business entity.](1) 

 

	(1)	This subsection shall be subject to deletion or revision with respect to issuances made following the Effective Date of the License Agreement as necessary to reflect
the facts as they exist as of such date of such issuance. 

 (d) [The
authorized capital stock of the Corporation consists of shares of Common Stock, of which shares are issued and outstanding prior to the sale of the stock contemplated hereunder. Other than as set forth above and except for the transactions
contemplated by this Agreement and the License Agreement, there are no other outstanding options, warrants, rights (including conversion or preemptive rights and rights of first refusal or similar rights) or agreements, orally or in
writing, for the purchase or acquisition from the Corporation of any of the Corporation’s
securities.](2) 

 

	(2)	This subsection shall be subject to revision with respect to issuances made following the Effective Date of the License Agreement as necessary to reflect the facts as
they exist as of such date of such issuances. 

  
 3 

 (e) The outstanding shares of the capital stock of the Corporation are duly
and validly issued, fully paid and non-assessable. The Shares, issuable upon execution of the License Agreement, shall, upon the terms of the License Agreement, be duly and validly issued, fully paid and non-assessable. 

(f) The Corporation is not, and will not be by virtue of entering into, and performing its obligations under, this
Agreement, in violation of any term of the Corporation’s Certificate of Incorporation, Bylaws or contractual undertakings or the provisions of any material agreement, mortgage, indenture, contract, lease agreement, instrument, judgment or
decree to which the Corporation is a party or by which it is bound. 
 (g) There are no actions, suits,
proceedings or investigations pending or, to the knowledge of the Corporation, currently threatened against the Corporation or its properties before any court or governmental body. 

(h) No representation or warranty by the Corporation in this Agreement, or in connection with the execution or performance
of this Agreement, contains or will contain any untrue statement of a material fact or omits or will omit to state a material fact required to be stated herein or necessary to make any statement not misleading. 

Section 5. Lock-Up Agreement. The Purchaser agrees, in connection with the first registration with the United
States Securities and Exchange Commission under the Securities Act of 1933, as amended, of the public sale of the Corporation’s Common Stock upon request of the Corporation or any underwriters managing such offering, not to sell, make any short
sale of, loan, grant any option for the purchase of or otherwise dispose of any such securities of the Corporation (other than those included in the registration) or the economic risk of the ownership thereof without the prior written consent of the
Corporation or such underwriters, as the case may be, for such period of time (not to exceed 180 days) from the effective date of such registration as the Corporation or the underwriters, as the case may be, shall specify; provided each officer
and director of the Corporation and all other holders of at least 5% of the Corporation’s voting securities will agree to the same restriction. Each such recipient agrees that the Corporation may instruct its transfer agent to place
stop-transfer notations in its records to enforce this paragraph. 
 Section 6. Miscellaneous 

6.1 Amendment. This Subscription Agreement may be amended only by written agreement among Purchaser and the Corporation.

 6.2 Survival of Representations, Warranties and Agreements. All representations, warranties and agreements made
in this Subscription Agreement, or any other instrument or document delivered in connection herewith or therewith, shall survive the execution and delivery hereof or thereof. 
 6.3 Further Assurances. All parties agree to execute any additional documents necessary to carry out the purposes of this Subscription Agreement. 

6.4 Notices. All demands, notices, approvals, consents, requests, and other communications hereunder shall be in writing and
shall be deemed to have been given when the writing is delivered, if given or delivered by hand, overnight delivery service or by facsimile (with confirmed receipt), or three (3) days after being mailed, if mailed, by first class, registered or
certified mail, postage prepaid, to the applicable address established under Section 13.3 of the License Agreement. 

  
 4 

 6.5 Governing Law; Successors and Assigns. This Subscription Agreement shall be
governed by the laws of the State of North Carolina. The rights and benefits of this Subscription Agreement shall inure to the benefit of, and be enforceable by, the successors and assigns of the parties. 

[Remainder of page intentionally left blank.] 

  
 5 

 IN WITNESS WHEREOF, the parties have duly executed this Agreement as of this
    day of 200  . 
  

			
	 CORPORATION:

	
	 CEMPRA PHARMACEUTICALS, INC.

		
	 By:
	 	 
	 Name:
	 	 
	 Title:
	 	 
	
	 PURCHASER:

	
	 OPTIMER PHARMACEUTICALS INC.

	
	  

	 Name:
	 	 
	 Title:
	 	 

  
 6 

 Schedule 6.1(2) 

Shareholders Agreement 

 AGREEMENT TO JOIN AS A PARTY TO STOCKHOLDERS AGREEMENT 

OF CEMPRA PHARMACEUTICALS, INC. 
 THIS AGREEMENT (the “Agreement”) dated as of March 31, 2006 is between CEMPRA PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and 

OPTIMER PHARMACEUTICALS, INC. (the “New Stockholder”). 

WITNESSETH: 
 WHEREAS, the Company and certain holders of capital stock of the Company (the “Existing Stockholders”) are parties to Stockholders Agreement, dated as of January 11, 2006, a copy of
which is attached hereto as Exhibit A (the “Stockholders”); 
 WHEREAS, pursuant to that certain
Collaborative Research and Development and License Agreement and Subscription Agreement between the parties, each dated March 31, 2006, New Stockholder has received one hundred four thousand one hundred sixty-six (104,166) shares of the
Company’s Common Stock, $.0001 par value (the “New Shares”); and 
 WHEREAS, Section 5.12 of the
Stockholders Agreement permits any party who acquires shares of the Company’s capital stock to become party to the Stockholders Agreement in the form of a joinder agreement whereby such party agrees to be bound and subject to the terms of the
Stockholders Agreement with respect to such shares held by such Company stockholder; and 
 WHEREAS, the New Stockholder must
join as party to the Shareholders Agreement in connection with their receipt of the New Shares. 
 NOW, THEREFORE, in
consideration of the issuance of New Shares to New Stockholder and for the premises, the covenants of the parties set forth below and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties
hereby agree as follows. 
 1. The undersigned New Stockholder hereby joins as party to and thereby agrees to be bound by the
terms and conditions of the Stockholders Agreement, effective as of the date hereof. 
 2. The Company hereby consents to New
Stockholder joining as party to the Stockholders Agreement. 
 3. For all purposes under the Stockholders Agreement the New
Stockholder shall be deemed a “Stockholder” and the New Shares shall be deemed to be “Shares.” 
 4. This
Agreement shall be governed by and interpreted in accordance with the laws of the State of North Carolina. 
 5. This Agreement
may be executed in one or more counterparts. 
 [The Next Page is the Signature Page] 

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

			
	OPTIMER PHARMACEUTICALS, INC.
		
	By:	 	 
	Name:	 	  

	Title:	 	  

	
	 CEMPRA PHARMACEUTICALS, INC.

		
	By:	 	 
	Name:	 	  

	Title:	 	  

  
 2 

 EXHIBIT A 

Stockholders Agreement 
  

 CEMPRA PHARMACEUTICALS, INC. 

STOCKHOLDERS AGREEMENT 
 This Stockholders Agreement (the “Agreement”) is made as of this 11th day of January, 2006, by and among Cempra Pharmaceuticals, Inc., a Delaware corporation (the
“Company”), and the persons owning shares of the capital stock of the Company listed on the Schedule of Stockholders attached hereto as Exhibit A (and any additional stockholder named in any amendment to
Exhibit A, referred to herein individually as a “Stockholder” and collectively as the “Stockholders”). 
 ARTICLE 1 RECITALS 
 1.1 The Stockholders are collectively the owners of
all the issued and outstanding capital stock of the Company (the “Shares”), as indicated on Exhibit A (which shall be amended from time to time to reflect purchases or transfers of Shares). 

1.2 The Company and the Stockholders realize that, in the event of the death or termination of employment of one of the Stockholders, or
the sale, transfer or encumbrance of his/its stock in the Company during his/its lifetime, should the stock of the Company owned by such Stockholder pass into the ownership or control of a person or entity other than the remaining Stockholders, it
would tend to disrupt the harmonious and successful management and control of the Company. 
 1.3 It is the earnest desire of
the Company and the Stockholders to avoid the happening of any such unfortunate contingencies by assuring to the remaining Stockholders a succession to the ownership and control of the Company through the acquisition of the stock of a Stockholder at
the time of his death, termination of employment or prior to the sale or encumbrance of such Stockholder’s stock. 
 In
consideration of the mutual covenants contained herein, and for other valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows: 

ARTICLE 2 TRANSFER OF SHARES 
 2.1 Prohibited Transfers. No Stockholder shall sell, assign, transfer or dispose of all or any of his/its Shares except in compliance with the terms of this Agreement. Notwithstanding anything
to the contrary contained in this Agreement, any Stockholder may transfer without the necessity of prior approval all or any of his/its Shares by way of gift to his spouse, to any of his lineal descendants or ancestors, or to any trust for the
benefit of any one or more of such Stockholder, his spouse or his lineal descendants or ancestors. The Company shall not be required to transfer on its books any capital stock transferred in violation hereof or to treat any transferee of capital
stock transferred in violation hereof as an owner or Stockholder. 
 2.2 Right of First Refusal on Dispositions.

 (a) If at any time a Stockholder (a “Selling Stockholder”) desires to sell or otherwise transfer all or any
part of his Shares pursuant to a bona fide offer from a third party (the “Proposed Transferee”), the Selling Stockholder shall submit a written offer (the “Offer”), by delivering the Offer to the Company and the
other Stockholders, to sell such Shares (the “Offered Shares”) to the Company on terms and conditions, including price, not less favorable than those on which the Selling Stockholder proposes to sell such Offered Shares to the
Proposed Transferee. The Offer shall disclose the identity of the Proposed Transferee, the number of Offered Shares proposed to be sold, the total number 

 
of Shares owned by the Selling Stockholder, the terms and conditions, including price, of the proposed sale, and any other material facts relating to the proposed sale. 

(b) If the Company does not purchase all of the Offered Shares within 30 days after receipt of notice of an Offer (the
“Option Period”), then the other Stockholders shall have a 30-day right, beginning on the day after the expiration of the Option Period, to purchase all such Offered Shares, on the terms and conditions disclosed in the Offer (the
“Second Option Period”), on a pro-rata basis based on the total Shares owned by all Stockholders electing to purchase the Offered Shares. Upon the expiration of the Second Option Period or the express rejection of the Offer by both
the Company and other Stockholders, whichever occurs earlier, the Selling Stockholder may sell all of the Offered Shares to the Proposed Transferee at any time within 90 days after such time, subject to the provisions of Section 2.3. Any
such sale shall be to the Proposed Transferee, at not less than the price and upon other terms and conditions, if any, not more favorable to the Proposed Transferee than those specified in the Offer. Any remaining Offered Shares not sold within such
90-day period shall again be subject to the requirements of a prior offer pursuant to this Section 2.2. If Offered Shares are sold pursuant to this Section 2.2 to any purchaser who is not a party to this Agreement, the purchaser of such
Offered Shares shall execute a counterpart of this Agreement as a precondition of the purchase of such Offered Shares and any Offered Shares sold to such purchaser shall continue to be subject to the provisions of this Agreement, including, without
limitation, the provisions of Article II. 
 2.3 Right of Participation in Sales. 

(a) If at any time a Stockholder desires to sell any Shares owned by him to a Proposed Transferee, and those Shares to be transferred have
not been purchased by the Company or other Stockholders under Section 2.2, each of the other Stockholders (other than those who have elected to purchase Shares pursuant to Section 2.2) shall have the right to sell to the Proposed
Transferee, as a condition to such sale by the Selling Stockholder, at the same price per share and on the same terms and conditions as involved in such sale by the Selling Stockholder, a pro rata portion of the amount of Shares proposed to
be sold to the Proposed Transferee. The “pro rata portion” of Shares which a Stockholder shall be entitled to sell to the Proposed Transferee shall be that number of Shares as shall equal the number of Offered Shares proposed to be
sold to the Proposed Transferee multiplied by a fraction, the numerator of which is the aggregate of all shares of Common Stock (including shares issuable upon conversion or exercise of Preferred Stock, warrants, options or other convertible
securities held by such person) which are then held by the Participating Stockholder (as defined below), and the denominator of which is the aggregate of all shares of Common Stock (including shares issuable upon conversion or exercise of Preferred
Stock warrants, options or other convertible securities) which are then held by the Selling Stockholder and all Stockholders wishing to participate in any sale under this Section 2.3. 

(b) Each Stockholder who wishes to make a sale to a Proposed Transferee which is subject to this Section 2.3 shall, after complying
with the provisions of Section 2.2, give to each other Stockholder notice of such proposed sale, and stating that all Offered Shares were not purchased pursuant to the Offer as discussed in Section 2.2. Such notice shall be given at least
20 days prior to the date of the proposed sale to the Proposed Transferee. Each other Stockholder wishing to participate in such sale (a “Participating Stockholder”) shall notify the Selling Stockholder in writing of such
intention within 15 days after such Participating Stockholder’s receipt of the notice described in the preceding sentence. 
 (c) The Selling Stockholder and each Participating Stockholder shall sell to the Proposed Transferee all, or at the option of the Proposed Transferee, any part of the Shares proposed to be sold by them at
not less than the price and upon other terms and conditions, if any, not more favorable to the Proposed Transferee than those in the notice provided by the Selling Stockholder under Section 2.3(b) above; provided, however, that any
purchase of less than all of such Shares by the 

  
 2 

 
Proposed Transferee shall be made from the Selling Stockholder and each Participating Stockholder pro rata based upon the relative number of the Shares that the Selling Stockholder and
each Participating Stockholder is otherwise entitled to sell pursuant to Section 2.3(a). 
 (d) If any Shares are sold
pursuant to this Section 2.3 to any purchaser who is not a party to this Agreement, the purchaser of such Shares shall execute a counterpart of this Agreement as a precondition to the purchase of such Shares and such Shares shall continue to be
subject to the provisions of this Agreement. 
 2.4 Transferee Restrictions. Any transferee of capital stock under
this Agreement must become a party to this Agreement by executing any instruments or documents that may be deemed necessary or advisable by counsel to the Company to make such transferee a party to this Agreement, or such transfer shall be deemed
null and void. If and when all the capital stock of the Selling Stockholder shall have been transferred in accordance with the terms and conditions of this Agreement, such person shall cease to be a Stockholder under this Agreement. 

ARTICLE 3 VOTING OF SHARES 
 3.1 Election of Directors. In any and all elections of directors of the Company (whether at a meeting or by written consent in lieu of a meeting), each Stockholder shall vote or cause to be
voted all Shares (as defined in Section 4 below) owned by him or it, or over which he or it has voting control, and to otherwise use his or its best efforts to elect: 
 (a) Four (4) designees of Prabhavathi Fernandes, Ph.D.; and 
 (b) any
additional designee or designees approved by Prabhavathi Fernandes, Ph.D. 
 3.2 Vacancies. Any vacancy in the
office of a director shall be filled by either (a) a unanimous vote of the Board of Directors, or (b) in the manner specified in Section 3.1 hereof. 
 3.3 Definition of Shares. The term “Shares” shall mean and include any and all shares of Common Stock and/or shares of Preferred Stock of the Company by whatever name called,
which carry voting rights (including voting rights which arise by reason of default) and shall include any shares now owned or subsequently acquired by a Stockholder, however acquired, including without limitation by stock splits and stock
dividends. 
 3.4 Size of Board. The Stockholders shall vote or cause to be voted (whether by actual vote or by
written consent), all shares owned by him, her or it, or over which he, she or it has voting control, and to otherwise use his, her or its best efforts to ensure that the size of the Company’s Board of Directors shall be set at four members,
unless otherwise agreed to by Prabhavathi Fernandes, Ph.D.. 
 ARTICLE 4 TERMINATION AND REVOCATION 

4.1 Termination. This Stockholders’ Agreement shall continue in effect as long as at least two of the Stockholders are
living or in existence and own shares of the Company’s capital stock, and shall terminate upon (i) the death of one of the last remaining two Stockholders and the consummation of the transfer to, and payment for, his shares by the last
remaining Stockholder or the Company, as the case may be, (ii) the closing of the Company’s sale of all or substantially all of its assets or the acquisition of the Company by another entity by means of merger or other transaction, or
(iii) the closing of the Company’s initial public offering covering the offer and sale of its Common Stock for the account of the Company. 

  
 3 

 4.2 Revocation. The voting agreements contained herein are coupled with an interest
and may not be revoked, except in accordance with the amendment provisions of Section 5.8 hereof. 
 ARTICLE 5
MISCELLANEOUS 
 5.1 Restrictive Legend. All certificates representing Shares owned or hereafter acquired by the
Stockholders or any permitted transferee of any Stockholder bound by this Agreement shall have affixed thereto a legend substantially in the following form: 
 THE SHARES OF STOCK REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE TERMS AND PROVISIONS OF A STOCKHOLDERS AGREEMENT BY AND AMONG THE COMPANY AND ITS STOCKHOLDERS, AND ARE TRANSFERABLE ONLY IN
ACCORDANCE WITH THE TERMS AND CONDITIONS OF SUCH AGREEMENT. A COPY OF THE STOCKHOLDERS AGREEMENT IS AVAILABLE FOR INSPECTION AT THE OFFICES OF THE SECRETARY OF THE COMPANY. 
 5.2 Action as Director. No party hereto who is or may become a director of the Company either agrees or implies that he will exercise his actions as a director in any manner other than in
accordance with his considered judgment at such time with respect to the best interests of the Company and all of its stockholders. 
 5.3 Transferees; Binding Effect. This Agreement shall be binding upon the Stockholders and their respective heirs, executors, administrators, legal representatives, successors and assigns.

 5.4 Severability. The provisions of this Agreement are severable, so that the invalidity or unenforceability of
any provision of this Agreement shall not affect the validity or enforceability of any other term or provision of this Agreement, which shall remain in full force and effect. 
 5.5 Specific Enforcement. Each Stockholder expressly agrees that other Stockholders and the Company may be irreparably damaged if this Agreement is not specifically enforced. Upon a breach or
threatened breach of the terms, covenants and/or conditions of this Agreement by any Stockholder, the other Stockholders and the Company shall, in addition to all other remedies, each be entitled to apply for a temporary or permanent injunction,
and/or a decree for specific performance, in accordance with the provisions hereof. 
 5.6 Governing Law. This
Agreement shall be governed by, and construed and enforced in accordance with, the laws of the State of North Carolina. 
 5.7
Notices. Any and all notices or elections permitted or required to be made under this Agreement shall be in writing, signed by the party giving such notice or election and shall be delivered personally, or sent by registered or certified
mail, return receipt requested, to the other parties at their respective addresses shown below. 
 5.8 Complete Agreement;
Amendments. This Agreement constitutes the full and complete agreement of the parties hereto with respect to the subject matter hereof. No amendment, modification or termination of any provision of this Agreement shall be valid unless in writing
and signed by each of the parties hereto. 

  
 4 

 5.9 Pronouns. Whenever the content may require, any pronouns used in this
Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice-versa. 
 5.10 Counterparts. This Agreement may be executed in any number of counterparts, each of which shall constitute one Agreement binding on all the parties hereto. 

5.11 Captions. Captions of sections have been added only for convenience and shall not be deemed to be a part of this
Agreement. 
 5.12 Additional Stockholders. Any parties who acquire shares of the Company’s capital stock after
the date hereof who as a condition of such acquisition are required to become party to this Agreement, may do so by executing a form of joinder agreement whereby such party agrees to be bound and subject to the terms of this Agreement with respect
to the Shares held by such Company stockholder. Upon execution of such joinder agreement, Exhibit A shall be amended to reflect the addition of such stockholders and its Shares. 

[THE NEXT PAGE IS THE SIGNATURE PAGE] 

  
 5 

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

			
	THE COMPANY:
	
	CEMPRA PHARMACEUTICALS, INC.
		
	By:	 	 
	Name:	 	 
	Title:	 	 

  

			
	THE STOCKHOLDERS:
		
	  	 	(SEAL)
		
	  	 	(SEAL)
		
	  	 	(SEAL)

  
 6 

 EXHIBIT A 

SCHEDULE OF STOCKHOLDERS 
  

					
	 Founders
	  	Number of Shares
of Common Stock	 
	 Prabhavathi Fernandes, Ph.D.
	  	 	1,200,000	  
	 Cindy Ingram
	  	 	400,000	  
	 Elizabeth Cali Cutrone Downs
	  	 	400,000	  
	 Optimer Pharmaceuticals, Inc.
	  	 	104,166	  
		  	  
	  
	 
	 TOTAL:
	  	 	2,104,166	  
		  	  
	  
	 

 Schedule 8.5 

Press Release 
 [LOGO]

 FOR IMMEDIATE RELEASE 

Cempra Pharmaceuticals, Inc. 

Prabhavathi Fernandes, Ph.D. 
 + 1 919
467 1716 
 CEMPRA PHARMACEUTICALS RECEIVES EXCLUSIVE RIGHTS FROM OPTIMER PHARMACEUTICALS FOR ITS MACROLIDE ANTIBACTERIAL
PROGRAM 
 MORRISVILLE, NC April 4, 2006 Cempra Pharmaceuticals, Inc. announced that Optimer Pharmaceuticals has
granted to Cempra exclusive worldwide rights (except ASEAN countries) to patents and know-how related to its macrolide/ketolide antibacterial program. Cempra has licensed rights to discover, develop and commercialize drugs based on the class of
compounds called macrolides and ketolides. Optimer will receive an equity position in Cempra, as well as royalties and milestone payments from any drugs and drug candidates developed and/or co-developed by Cempra. The license includes joint drug
discovery and development activities at both companies. 
 Included in the license agreement are several pre-clinical compounds
in addition to ground-breaking chemistry technology for creating the next generation of macrolides and ketolides. Pre-clinical candidates derived from this technology have been shown to possess potent activity against multi-drug resistant
Streptococcus pnuemoniae and Streptococcus pyogenes. The most advanced lead, is orally active with potent efficacy in animal models after once-a-day administration. This lead will be initially developed for respiratory tract infections in
adults and children, including sinusitis, pharyngitis, and community acquired mild to moderate pneumonia. 
 “We are
extremely happy that Optimer has chosen to license their macrolide patents and know-how to Cempra Pharmaceuticals to develop and commercialize new macrolides that could be useful in the armamentarium for treating drug resistant bacteria” said
Prabhavathi Fernandes, Ph.D., Cempra’s President and Chief Executive Officer. She added, “This license will be the founding stone of Cempra and will allow us to build a company focused on developing a portfolio of antibacterial
compounds.” 
 Dr. Michael Chang, President and CEO of Optimer said “Optimer is enthusiastic about this
opportunity to move some of our earlier stage programs forward. Cempra has recruited leaders in antibacterial drug discovery and development and by licensing these macrolides to Cempra, we are enhancing the potential to realize value from our
macrolide program as we focus our resources on other later stage products.” 
 About Macrolide Antibiotics

Macrolides such Clarithromycin, Azithromycin and Telithromycin are favored by physicians and pediatricians for use in upper and lower
respiratory tract infections where the primary pathogens could be S. pneumoniae, S. aureus, S. pyogenes, H. influenzae, M. catarrhalis, and Legionella pneumophila. Macrolides are also used to treat Helicobater pylori
gastritis. Many of these pathogens are now resistant to currently available macrolides. 

 About Optimer Pharmaceuticals 

Optimer Pharmaceuticals, Inc. in San Diego, California (www.optimerpharma.com), a privately held biotechnology company and leader in
carbohydrate chemistry, has a strong portfolio of late-stage anti-infective products. Older generation antibiotics were mostly derived from natural products and these antibiotics have key sugar components that contribute to their antibacterial
properties. The sugar components of antibiotics have been generally beyond the reach of medicinal chemistry. Optimer has applied its unique sugar chemistry technology to modify regions of macrolides and ketolides that could not be addressed
previously, discovering new antibiotics that are effective against drug-resistant bacteria. 
 About Cempra Pharmaceuticals 

Cempra Pharmaceuticals, Inc., located in Morrisville, North Carolina, is a newly founded biotechnology company focused on
anti-infectives. The company was founded in 2006 by Prabhavathi Fernandes, Ph.D. who was the leading microbiologist for Clarithromycin development at Abbott. Cempra is committed to the development of best-in-class antibiotics to meet urgent and
unmet needs to treat drug resistant bacteria. 
 This press release contains statements that constitute “forward-looking
statements These statements contain information that is not historical fact and are essentially predictions and are subject to risks and uncertainties, including risks associated with our ability to raise capital, the success of pre-clinical studies
and clinical trials, intellectual property risks, the difficulty of predicting FDA filings and approvals, and market acceptance. 
 # # # 

  
 2 

 December 31, 2008 
 Optimer Pharmaceuticals, Inc. 
 10110 Sorrento Valley Road, Suite C 

San Diego, California 92121 

Attention: John Prunty, Chief Financial Officer 
 Cempra Pharmaceuticals, Inc. (the “Company”) and Optimer Pharmaceuticals, Inc. (“Optimer”) are parties to that certain Collaborative Research and Development and License
Agreement dated March 31, 2006 (the “License Agreement”). Pursuant to Sections 6.2(a) and 6.2(b) of that License Agreement, Optimer may elect, upon written request to the Company, that it be paid certain milestone
payments in shares of Cempra capital stock (“Cempra Capital Stock”) rather than in cash, such Cempra Capital Stock having a Fair Market Value calculated as of the date the respective milestone is achieved equal to the value of the
milestone payments, as the case may be. All capitalized terms not otherwise defined in this Letter Agreement shall have the meanings ascribed to them in the License Agreement. 

As you may be aware, the Company plans to engage in a reorganization whereby the Company will merge with Cempra Merger Corp.
(“MergeCo”), a Delaware corporation and wholly-owned subsidiary of Cempra Holdings, LLC, a Delaware limited liability company (the “Holding Company”). Upon such merger, the separate corporate existence of MergeCo will
terminate, the Company will remain as the surviving entity and the stockholders of the Company will receive units of the Holding Company (“Holding Company Units”) in exchange for their shares of Cempra Capital Stock (the
“Reorganization”). The rights belonging to each respective class or series of Holding Company Units will be essentially the same as those of the corresponding class or series of Cempra Capital Stock. Subsequent to the
Reorganization, the Company will distribute its shares of CEM-102 Pharmaceuticals, Inc., the Company’s wholly-owned subsidiary that holds assets unrelated to the technology licensed under the License Agreement, to the Holding Company (the
“Spin-Off”). 
 As a result of the Reorganization and Spin-Off, it is currently intended that the equity holdings for
the combined company will be held, and the ultimate liquidity for that equity will be realized, at the Holding Company level. Therefore, the parties find it necessary to modify Sections 1.15, 6.2(a), 6.2(b) and 6.2(e) of the License
Agreement, which refer to Cempra Capital Stock in the context of milestone payments described in Sections 6.2(a) and 6.2(b) of the License Agreement, to refer to Holding Company equity. This letter agreement reflects the parties’
mutual intent to modify those Sections so as to use the term “Holding Company Units” in lieu of “Cempra Capital Stock” in each phase where used or referenced. Except as specifically modified herein, the License Agreement
shall remain in full force and effect as originally executed. 
 By their execution below, the parties agree that, upon the
completion of the Reorganization, the references to “Cempra Capital Stock” in Sections 1.15, 6.2(a), 6.2(b) and 6.2(e) of the License Agreement will be modified to become “Holding Company Units” (as defined in this
Letter Agreement). By its execution below, the Holding Company agrees to issue Holding Company Units to Optimer when, if and as required under the terms of the License Agreement, as modified by this Letter Agreement. 

[THE NEXT PAGE IS THE SIGNATURE PAGE] 

									
	CEMPRA PHARMACEUTICALS, INC.	  		  	OPTIMER PHARMACEUTICALS, INC.
					
	By:	  	 /s/ Prabhavathi Fernandes
	  		  	By:	  	 /s/ John Prunty

		  	Prabhavathi Fernandes, Ph.D.	  		  		  	John Prunty
		  	Chief Executive Officer and President	  		  		  	Chief Financial Officer
					
		  	CEMPRA HOLDINGS, LLC	  		  		  	
					
	By:	  	 /s/ Prabhavathi Fernandes
	  		  		  	
		  	Prabhavathi Fernandes, Ph.D.	  		  		  	
		  	Chief Executive Officer and President	  		  		  	

  
 2

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