EX-10.6




 Exhibit 10.6 

APEXIGEN, INC. 

2022 EMPLOYEE STOCK PURCHASE PLAN 

1. Purpose. The purpose of this Plan is to provide employees of the Company and its Designated Companies with an opportunity to
purchase Common Stock through accumulated Contributions. The Company intends for this Plan to have two components: a component that is intended to qualify as an “employee stock purchase plan” under Code Section 423 (the
“423 Component”) and a component that is not intended to qualify as an “employee stock purchase plan” under Code Section 423 (the “Non-423
Component”). The provisions of the 423 Component, accordingly, will be construed so as to extend and limit Plan participation in a uniform and nondiscriminatory basis consistent with the requirements of Code Section 423. In
addition, this Plan authorizes the grant of an option to purchase shares of Common Stock under the Non-423 Component that does not qualify as an “employee stock purchase plan” under Code
Section 423; an option granted under the Non-423 Component will provide for substantially the same benefits as an option granted under the 423 Component, except that a Non-423 Component option may include features necessary to comply with applicable non-U.S. laws pursuant to rules, procedures or
sub-plans adopted by the Administrator. Except as otherwise provided herein or by the Administrator, the Non-423 Component will operate and be administered in the
same manner as the 423 Component. 
 2. Definitions. 

2.1 “Administrator” means the Board or any Committee designated by the Board to administer this Plan pursuant to
Section 4. 
 2.2 “Applicable Laws” means the legal and regulatory requirements relating to the administration of equity-based awards, including the related issuance of shares of Common Stock, including under U.S. federal and state corporate laws, U.S. federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of any non-U.S. country or jurisdiction where options are, or will be, granted under this Plan. 

2.3 “Board” means the Board of Directors of the Company. 

2.4 “Change in Control” means the occurrence of any of the following events: 

(a) Change in Ownership of the Company. A change in the ownership of the Company which occurs on the date that any one person, or more
than one person acting as a group (“Person”), acquires ownership of the stock of the Company that, together with the stock held by such Person, constitutes more than 50% of the total voting power of the stock of the Company;
provided, however, that for purposes of this subsection (a), the acquisition of additional stock by any one Person, who is considered to own more than 50% of the total voting power of the stock of the Company will not be considered a Change in
Control; provided, further, that any change in the ownership of the stock of the Company as a result of a private financing of the Company that is approved by the Board also will not be considered a Change in Control. Further, if the stockholders of
the Company immediately before such change in ownership continue to retain immediately after the change in ownership, in substantially the same proportions as their ownership of shares of the 











 
Company’s voting stock immediately prior to the change in ownership, direct or indirect beneficial ownership of 50% or more of the total voting power of the stock of the Company or of the
ultimate parent entity of the Company, such event will not be considered a Change in Control under this subsection (a). For this purpose, indirect beneficial ownership will include an interest resulting from ownership of the voting securities
of one or more corporations or other business entities which own the Company, as the case may be, either directly or through one or more subsidiary corporations or other business entities; or 

(b) Change in Effective Control of the Company. If the Company has a class of securities registered pursuant to Section 12 of the
Exchange Act, a change in the effective control of the Company which occurs on the date that a majority of members of the Board is replaced during any 12-month period by Directors whose appointment or election
is not endorsed by a majority of the members of the Board prior to the date of the appointment or election. For purposes of this subsection (b), if any Person is considered to be in effective control of the Company, the acquisition of
additional control of the Company by the same Person will not be considered a Change in Control; or 
 (c) Change in Ownership of a
Substantial Portion of the Company’s Assets. A change in the ownership of a substantial portion of the Company’s assets which occurs on the date that any Person acquires (or has acquired during the 12-month period ending on the date of the most recent acquisition by such Person or Persons) assets from the Company that have a total gross fair market value equal to or more than 50% of the total gross fair market
value of all of the assets of the Company immediately prior to such acquisition or acquisitions; provided, however, that for purposes of this subsection (c), the following will not constitute a change in the ownership of a substantial portion
of the Company’s assets: (i) a transfer to an entity that is controlled by the Company’s stockholders immediately after the transfer, or (ii) a transfer of assets by the Company to: (A) a stockholder of the Company
(immediately before the asset transfer) in exchange for or with respect to the Company’s stock, (B) an entity, 50% or more of the total value or voting power of which is owned, directly or indirectly, by the Company, (C) a Person,
that owns, directly or indirectly, 50% or more of the total value or voting power of all the outstanding stock of the Company, or (D) an entity, at least 50% of the total value or voting power of which is owned, directly or indirectly, by a
Person described in this subsection (c)(ii)(C). For purposes of this subsection (c), gross fair market value means the value of the assets of the Company, or the value of the assets being disposed of, determined without regard to any
liabilities associated with such assets. 
 For purposes of this Section 2.4, persons will be considered to be acting as a group if
they are owners of a corporation that enters into a merger, consolidation, purchase or acquisition of stock, or similar business transaction with the Company. 

Notwithstanding the foregoing, a transaction will not be deemed a Change in Control unless the transaction qualifies as a change in control
event within the meaning of Section 409A. 
 Further and for the avoidance of doubt, a transaction will not constitute a Change in
Control if: (x) its sole purpose is to change the jurisdiction of the Company’s incorporation, or (y) its sole purpose is to create a holding company that will be owned in substantially the same proportions by the persons who held the
Company’s securities immediately before such transaction. 

  
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 2.5 “Closing” means the closing of the merger contemplated by that certain
Business Combination Agreement by and among the Company, Apexigen, Inc., and certain other parties, dated March 17, 2022, as may be amended from time to time. 

2.6 “Code” means the U.S. Internal Revenue Code of 1986, as amended. Reference to a specific section of the Code or
regulation thereunder will include such section or regulation, any valid regulation or other formal guidance of general or direct applicability promulgated under such section, and any comparable provision of any future legislation or regulation
amending, supplementing or superseding such section or regulation. 
 2.7 “Committee” means a committee of the Board
appointed in accordance with Section 4. 
 2.8 “Common Stock” means the common stock of the Company. 

2.9 “Company” means Brookline Capital Acquisition Corp. (which, on or following the Closing, will be named Apexigen, Inc.), a
Delaware corporation, or any successor thereto. 
 2.10 “Compensation” means an Eligible Employee’s base straight time
gross earnings, but exclusive of payments for overtime, shift premium, commissions, incentive compensation, equity compensation, bonuses and other similar compensation. The Administrator, in its discretion, may, on a uniform and nondiscriminatory
basis, establish a different definition of Compensation for a subsequent Offering Period. 
 2.11 “Contributions” means the
payroll deductions and other additional payments that the Company may permit to be made by a Participant to fund the exercise of options granted pursuant to this Plan. 

2.12 “Designated Company” means any Subsidiary that has been designated by the Administrator from time to time in its sole
discretion as eligible to participate in this Plan. For purposes of the 423 Component, only the Company and its Subsidiaries may be Designated Companies, provided, however that at any given time, a Subsidiary that is a Designated Company under
the 423 Component will not be a Designated Company under the Non-423 Component. 
 2.13
“Director” means a member of the Board. 
 2.14 “Effective Date” means the date of the Closing. 

2.15 “Eligible Employee” means any individual who is a common law employee providing services to the Company or a Designated
Company and is customarily employed for at least 20 hours per week and more than 5 months in any calendar year by the Employer, or any lesser number of hours per week or number of months in any calendar year established by the Administrator (if
required under Applicable Laws) for purposes of any separate Offering or for Participants in the Non-423 Component. For purposes of this Plan, the employment relationship will be treated as continuing
intact while the individual is on sick leave or other leave of absence that the Employer approves or is legally protected under Applicable Laws with respect to the Participant’s participation in this Plan. Where the period of leave exceeds 3
months and the individual’s right to 

  
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reemployment is not guaranteed either by statute or by contract, the employment relationship will be deemed to have terminated 3 months and 1 day following the commencement of such leave. The
Administrator, in its discretion, from time to time may, prior to an Enrollment Date for all options to be granted on such Enrollment Date in an Offering, determine (for each Offering under the 423 Component, on a uniform and nondiscriminatory
basis or as otherwise permitted by U.S. Treasury Regulations Section 1.423-2) that the definition of Eligible Employee will or will not include an individual if he or she: (a) has not completed
at least 2 years of service since his or her last hire date (or such lesser period of time as may be determined by the Administrator in its discretion), (b) customarily works not more than 20 hours per week (or such lesser period of time as may
be determined by the Administrator in its discretion), (c) customarily works not more than 5 months per calendar year (or such lesser period of time as may be determined by the Administrator in its discretion), (d) is a highly compensated
employee within the meaning of Code Section 414(q), or (e) is a highly compensated employee within the meaning of Code Section 414(q) with compensation above a certain level or is an officer or subject to the disclosure requirements
of Section 16(a) of the Exchange Act, provided the exclusion is applied with respect to each Offering under the 423 Component in an identical manner to all highly compensated individuals of the Employer whose employees are participating in
that Offering. Each exclusion will be applied with respect to an Offering under the 423 Component in a manner complying with U.S. Treasury Regulations Section 1.423-2(e)(2)(ii). Such exclusions may
be applied with respect to an Offering under the Non-423 Component without regard to the limitations of U.S. Treasury Regulations Section 1.423-2. 

2.16 “Employer” means the employer of the applicable Eligible Employee(s). 

2.17 “Enrollment Date” means the first Trading Day of each Offering Period. 

2.18 “Exchange Act” means the U.S. Securities Exchange Act of 1934, as amended, including the rules and regulations
promulgated thereunder. 
 2.19 “Exercise Date” means the last Trading Day of a Purchase Period. Notwithstanding the
foregoing, in the event that an Offering Period is terminated prior to its expiration pursuant to Section 18, the Administrator, in its sole discretion, may determine that any Purchase Period also terminating under such Offering Period will
terminate without options being exercised on the Exercise Date(s) that otherwise would have occurred on the last Trading Day of such Purchase Period. 

2.20 “Fair Market Value” means, as of any date and unless the Administrator determines otherwise, the value of Common Stock
determined as follows: 
 (a) If the Common Stock is listed on any established stock exchange or a national market system, including the New
York Stock Exchange or the Nasdaq Global Select Market, the Nasdaq Global Market, or the Nasdaq Capital Market of The Nasdaq Stock Market, its Fair Market Value will be the closing sales price for such stock (or, if no closing sales price was
reported on that date, as applicable, on the last Trading Day such closing sales price was reported) as quoted on such exchange or system on the date of determination, as reported in The Wall Street Journal or such other source as the
Administrator deems reliable; 

  
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 (b) If the Common Stock is regularly quoted by a recognized securities dealer but selling
prices are not reported, the Fair Market Value of a share of Common Stock will be the mean between the high bid and low asked prices for the Common Stock on the day of determination (or if no bids and asks were reported on that date, as applicable,
on the last Trading Day such bids and asks were reported), as reported in The Wall Street Journal or such other source as the Administrator deems reliable; or 

(c) In the absence of an established market for the Common Stock, the Fair Market Value will be determined in good faith by the
Administrator. 
 The determination of fair market value for purposes of tax withholding may be made in the Administrator’s discretion
subject to Applicable Laws and is not required to be consistent with the determination of Fair Market Value for other purposes. 
 2.21
“Fiscal Year” means the fiscal year of the Company. 
 2.22 “New Exercise Date” means a new Exercise Date
if the Administrator shortens any Offering Period then in progress. 
 2.23 “Offering” means an offer under this Plan of an
option that may be exercised during an Offering Period as further described in Section 6. For purposes of this Plan, the Administrator may designate separate Offerings under this Plan (the terms of which need not be identical) in which Eligible
Employees of one or more Employers will participate, even if the dates of the applicable Offering Periods of each such Offering are identical and the provisions of this Plan will separately apply to each Offering. To the extent permitted by U.S.
Treasury Regulations Section 1.423-2(a)(1), the terms of each Offering need not be identical provided that the terms of this Plan and an Offering together satisfy U.S. Treasury Regulations Section 1.423-2(a)(2) and (a)(3). 
 2.24 “Offering Period” means a period
beginning on such date as may be determined by the Administrator, in its discretion, and ending on such Exercise Date as may be determined by the Administrator, in its discretion, during which an option granted pursuant to this Plan may be
exercised. The duration and timing of Offering Periods may be changed pursuant to Sections 6 and 18. 
 2.25
“Parent” means a “parent corporation,” whether now or hereafter existing, as defined in Code Section 424(e). 

2.26 “Participant” means an Eligible Employee that participates in this Plan. 

2.27 “Plan” means this Apexigen, Inc. 2022 Employee Stock Purchase Plan. 

2.28 “Purchase Period” means the period during an Offering Period and during which shares of Common Stock may be purchased on
behalf of Participants thereunder in accordance with the terms of this Plan. Purchase Periods will have such duration as determined by the Administrator, commencing after one Exercise Date and ending with the next Exercise Date, except that the
first Purchase Period of any Offering Period will commence on the Enrollment Date and end with the next Exercise Date. Unless the Administrator provides otherwise, a Purchase Period in an Offering Period will have the same duration as, and coincide
with the length of, such Offering Period. 

  
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 2.29 “Purchase Price” means an amount equal to 85% of the Fair Market Value
of a share of Common Stock on the Enrollment Date or on the Exercise Date, whichever is lower; provided however, that the Purchase Price may be determined for any Offering Period by the Administrator subject to compliance with Code Section 423
(or any successor rule or provision or any other Applicable Laws, regulation or stock exchange rule) or pursuant to Section 18. 
 2.30
“Section 409A” means Code Section 409A and the U.S. Treasury Regulations and guidance thereunder, and any applicable state law equivalent, as each may be promulgated, amended or modified from time to time.

 2.31 “Subsidiary” means a “subsidiary corporation,” whether now or hereafter existing, as defined in Code
Section 424(f). 
 2.32 “Trading Day” means a day that the primary stock exchange, national market system, or other
trading platform, as applicable, upon which the Common Stock is listed (or otherwise trades regularly, as determined by the Administrator, in its sole discretion) is open for trading. 

2.33 “U.S. Treasury Regulations” means the Treasury Regulations of the Code. Reference to a specific Treasury Regulation or
Section of the Code will include such Treasury Regulation or Section, any valid regulation promulgated under such Section, and any comparable provision of any future legislation or regulation amending, supplementing or superseding such Section or
regulation. 
 3. Stock. 

3.1 Stock Subject to this Plan. Subject to adjustment upon changes in capitalization of the Company as provided in Section 17 and
the automatic increase set forth in Section 3.2, the maximum number of shares of Common Stock that will be made available for sale under this Plan will be 257,341 shares of Common Stock. The shares of Common Stock may be authorized, but
unissued, or reacquired Common Stock. 
 3.2 Automatic Share Reserve Increase. Subject to adjustment upon changes in capitalization
of the Company as provided in Section 17, the number of shares of Common Stock available for issuance under this Plan will be increased on the first day of each Fiscal Year beginning with the 2023 Fiscal Year, in an amount equal to the least of
(a) 536,126 shares of Common Stock, (b) a number of shares of Common Stock equal to 1% of the total number of shares of all classes of common stock of the Company on the last day of the immediately preceding Fiscal Year, or (c) such
number of Shares determined by the Administrator no later than the last day of the immediately preceding Fiscal Year. 

  
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 4. Administration. This Plan will be administered by the Board or a Committee
appointed by the Board, which Committee will be constituted to comply with Applicable Laws. The Administrator will have full and exclusive discretionary authority to 

(a) construe, interpret and apply the terms of this Plan, 

(b) delegate ministerial duties to any of the Company’s employees, 

(c) designate separate Offerings under this Plan, 

(d) designate Subsidiaries as participating in the 423 Component or Non-423 Component, 

(e) determine eligibility, 
 (f)
adjudicate all disputed claims filed under this Plan, and 
 (g) establish such procedures that it deems necessary or advisable for the
administration of this Plan (including to adopt such procedures, sub-plans, and appendices to the enrollment agreement as are necessary or appropriate to permit the participation in this Plan by employees who
are foreign nationals or employed outside the U.S., the terms of which sub-plans and appendices may take precedence over other provisions of this Plan, with the exception of Section 3, but unless
otherwise superseded by the terms of such sub-plan or appendix, the provisions of this Plan will govern the operation of such sub-plan or appendix). Unless otherwise
determined by the Administrator, the Eligible Employees eligible to participate in each sub-plan will participate in a separate Offering under the 423 Component, or if the terms would not qualify under
the 423 Component, in the Non-423 Component, in either case unless such designation would cause the 423 Component to violate the requirements of Code Section 423. 

Without limiting the generality of the foregoing, the Administrator is specifically authorized to adopt rules and procedures regarding
eligibility to participate, the definition of Compensation, handling of Contributions, making of Contributions to this Plan (including in forms other than payroll deductions), establishment of bank or trust accounts to hold Contributions, payment of
interest, conversion of local currency, obligations to pay payroll tax, determination of beneficiary designation requirements, withholding procedures and handling of stock certificates that vary with applicable local requirements. The Administrator
also is authorized to determine that, to the extent permitted by U.S. Treasury Regulations Section 1.423-2(f), the terms of an option granted under this Plan or an Offering to citizens or residents of a non-U.S. jurisdiction will be less favorable than the terms of options granted under this Plan or the same Offering to employees resident solely in the U.S. Every finding, decision and determination made by the
Administrator will, to the full extent permitted by law, be final and binding upon all parties. 
 5. Eligibility. 

5.1 Offering Periods. Any Eligible Employee on a given Enrollment Date will be eligible to participate in this Plan, subject to the
requirements of Section 7. 
 5.2 Non-U.S. Employees. Eligible Employees who are
citizens or residents of a non-U.S. jurisdiction (without regard to whether they also are citizens or residents of the United States or resident aliens (within the meaning of Code Section 7701(b)(1)(A)))
may be excluded from participation in this Plan or an Offering if the participation of such Eligible Employees is prohibited under the laws of the applicable jurisdiction or if complying with the laws of the applicable jurisdiction would cause this
Plan or an Offering to violate Code Section 423. In the case of the Non-423 Component, an Eligible Employee may be excluded from participation in this Plan or an Offering if the Administrator has
determined that participation of such Eligible Employee is not advisable or practicable. 

  
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 5.3 Limitations. Any provisions of this Plan to the contrary notwithstanding, no
Eligible Employee will be granted an option under this Plan (a) to the extent that, immediately after the grant, such Eligible Employee (or any other person whose stock would be attributed to such Eligible Employee pursuant to Code
Section 424(d)) would own capital stock of the Company or any Parent or Subsidiary of the Company or hold outstanding options to purchase such stock possessing 5% or more of the total combined voting power or value of all classes of the capital
stock of the Company or of any Parent or Subsidiary of the Company, or (b) to the extent that his or her rights to purchase stock under all employee stock purchase plans (as defined in Code Section 423) of the Company or any Parent or
Subsidiary of the Company accrues at a rate, which exceeds $25,000 worth of stock (determined at the Fair Market Value of the stock at the time such option is granted) for each calendar year in which such option is outstanding at any time, as
determined in accordance with Code Section 423 and the regulations thereunder. 
 6. Offering Periods. This Plan will be
implemented by Offering Periods as established by the Administrator from time to time. Offering Periods will expire on the earliest to occur of (a) the completion of the purchase of shares on the last Exercise Date occurring within 27 months of
the applicable Enrollment Date on which the option to purchase shares was granted under this Plan, or (b) such shorter period established prior to the Enrollment Date of the Offering Period by the Administrator, from time to time, in its
discretion, on a uniform and nondiscriminatory basis, for all options to be granted on such Enrollment Date. The Administrator will have the power to change the duration of Offering Periods (including the commencement dates thereof) with respect to
future Offerings without stockholder approval if such change is announced prior to the scheduled beginning of the first Offering Period to be affected thereafter; provided, however, that no Offering Period may last more than 27 months. 

7. Participation. An Eligible Employee may participate in this Plan pursuant to Section 5.1 by (a) submitting to the
Company’s stock administration office (or its designee), a properly completed subscription agreement authorizing Contributions in the form provided by the Administrator for such purpose (which may be similar to the form attached hereto as
Exhibit A), or (b) following an electronic or other enrollment procedure determined by the Administrator, in either case, on or before a date determined by the Administrator prior to an applicable
Enrollment Date. 
 8. Contributions. 

8.1 Contribution Amounts. At the time a Participant enrolls in this Plan pursuant to Section 7, he or she will elect to have
Contributions (in the form of payroll deductions or otherwise, to the extent permitted by the Administrator) made on each pay day during the Offering Period in an amount not exceeding 15% of the Compensation, which he or she receives on each pay day
during the Offering Period; provided, however, that unless and until determined otherwise by the Administrator, should a pay day occur on an Exercise Date, a Participant will have any Contributions made on such day applied to his or her account
under the then-current Purchase Period or Offering Period (i.e., for which the Exercise Date occurs on such day). 

  
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 8.2 Contribution Methods. The Administrator, in its sole discretion, may permit all
Participants in a specified Offering to contribute amounts to this Plan through payment by cash, check or other means set forth in the subscription agreement prior to each Exercise Date of each Offering Period. A Participant’s subscription
agreement will remain in effect for successive Offering Periods unless terminated as provided in Section 12 (or Participant’s participation is terminated as provided in Section 13). 

(a) In the event Contributions are made in the form of payroll deductions, such payroll deductions for a Participant will commence on the
first pay day following the Enrollment Date and will end on the last pay day on or prior to the last Exercise Date of such Offering Period to which such authorization is applicable, unless sooner terminated by the Participant as provided in
Section 12 (or Participant’s participation is terminated as provided in Section 13). 
 (b) All Contributions made for a
Participant will be credited to his or her account under this Plan and Contributions will be made in whole percentages of his or her Compensation only. A Participant may not make any additional payments into such account. 

8.3 Participant Changes to Contributions. A Participant may discontinue his or her participation in this Plan as provided under
Section 12. Until and unless determined otherwise by the Administrator, in its sole discretion, during any Offering Period, a Participant may not increase the rate of his or her Contributions and may decrease the rate of his or her
Contributions only one time, provided that such decrease is to a Contribution rate of 0%. In addition, until and unless determined otherwise by the Administrator, in its sole discretion, during any Offering Period, a Participant may increase or
decrease the rate of his or her Contributions (as a whole percent to a rate between 0% and the maximum percentage specified in Section 8.1), which Contribution rate adjustment will become effective upon the commencement of the next Offering
Period and remain in effect for subsequent Offering Periods and, except as set forth in the immediately preceding sentence, any such adjustment will not affect the Contribution rate for any ongoing Offering Period. 

(a) A Participant may make a Contribution rate adjustment pursuant to this Section 8.3 by (A) properly completing and submitting to
the Company’s stock administration office (or its designee), a new subscription agreement authorizing the change in Contribution rate in the form provided by the Administrator for such purpose, or (B) following an electronic or other
procedure prescribed by the Administrator, in either case, on or before a date determined by the Administrator prior to (x) the scheduled beginning of the first Offering Period to be affected or (y) an applicable Exercise Date, as
applicable. If a Participant has not followed such procedures to change the rate of Contributions, the rate of his or her Contributions will continue at the originally elected rate throughout the Offering Period and future Offering Periods (unless
the Participant’s participation is terminated as provided in Sections 12 or 13). 
 (b) The Administrator may, in its sole
discretion, limit or amend the nature or number of Contribution rate changes (including to permit, prohibit or limit increases or decreases to rate changes) that may be made by Participants during any Purchase Period or Offering Period, and may
establish such other conditions or limitations as it deems appropriate for Plan administration. 

  
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 (c) Except as provided by this Section 8.3, any change in Contribution rate made
pursuant to this Section 8.3 will be effective as of the first full payroll period following 5 business days after the date on which the change is made by the Participant (unless the Administrator, in its sole discretion, elects to process
a given change in Contribution rate earlier). 
 8.4 Other Contribution Changes. Notwithstanding the foregoing, to the extent
necessary to comply with Code Section 423(b)(8) and Section 5.3 (which generally limit participation in an Offering Period pursuant to certain Applicable Laws), a Participant’s Contributions may be decreased to 0% by the Administrator
at any time during an Offering Period (or a Purchase Period, as applicable). Subject to Code Section 423(b)(8) and Section 5.3, Contributions will recommence at the rate originally elected by the Participant effective as of the beginning
of the first Offering Period (or Purchase Period, as applicable) scheduled to end in the following calendar year, unless the Participant’s participation has terminated as provided in Sections 12 or 13. 

8.5 Cash Contributions. Notwithstanding any provisions to the contrary in this Plan, the Administrator may allow Participants to
participate in this Plan via cash contributions instead of payroll deductions if (a) payroll deductions are not permitted or advisable under Applicable Laws, (b) the Administrator determines that cash contributions are permissible for
Participants participating in the 423 Component or (c) the Participants are participating in the Non-423 Component. 

8.6 Tax Withholdings. At the time the option is exercised, in whole or in part, or at the time some or all of the Common Stock issued
under this Plan is disposed of (or at any other time that a taxable event related to this Plan occurs), the Participant must make adequate provision for the Company’s or Employer’s federal, state, local or any other tax liability payable
to any authority including taxes imposed by jurisdictions outside of the U.S., national insurance, social security or other tax withholding or payment on account obligations, if any, which arise upon the exercise of the option or the disposition of
the Common Stock (or any other time that a taxable event related to this Plan occurs). At any time, the Company or the Employer may, but will not be obligated to, withhold from the Participant’s compensation the amount necessary for the Company
or the Employer to meet applicable withholding obligations, including any withholding required to make available to the Company or the Employer any tax deductions or benefits attributable to the sale or early disposition of Common Stock by the
Eligible Employee. In addition, the Company or the Employer may, but will not be obligated to, withhold from the proceeds of the sale of Common Stock or use any other method of withholding the Company or the Employer deems appropriate to the extent
permitted by U.S. Treasury Regulations Section 1.423-2(f). 
 8.7 Use of Funds. The
Company may use all Contributions received or held by it under this Plan for any corporate purpose, and the Company will not be obligated to segregate such Contributions except under Offerings or for Participants in the Non-423 Component for which Applicable Laws require that Contributions to this Plan by Participants be segregated from the Company’s general corporate funds or deposited with an independent third party,
provided that, if such segregation or deposit with an independent third party is required by Applicable Laws, it will apply to all Participants in the relevant Offering under the 423 Component, except to the extent otherwise permitted by U.S.
Treasury Regulations Section 1.423-2(f). Until shares of Common Stock are issued, Participants will have only the rights of an unsecured creditor with respect to such shares. 

  
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 9. Grant of Option. On the Enrollment Date of each Offering Period, each Eligible
Employee participating in such Offering Period will be granted an option to purchase on each Exercise Date during such Offering Period (at the applicable Purchase Price) up to a number of shares of Common Stock determined by dividing such Eligible
Employee’s Contributions accumulated prior to such Exercise Date and retained in the Eligible Employee’s account as of the Exercise Date by the applicable Purchase Price. 

9.1 Certain Option Limits. In no event will an Eligible Employee be permitted to purchase during each Offering Period more than 8,500
shares of Common Stock (subject to any adjustment pursuant to Section 17), and provided further that such purchase will be subject to the limitations set forth in Sections 3 and 5.3 and in the subscription agreement. The Administrator, in
its absolute discretion, may increase or decrease the maximum number of shares of Common Stock that an Eligible Employee may purchase during each Purchase Period or Offering Period, as applicable. 

9.2 Option Receipt. The Eligible Employee may accept the grant of an option under this Plan by electing to participate in this Plan in
accordance with the requirements of Section 7. 
 9.3 Option Term. Exercise of the option will occur as provided in
Section 10, unless the Participant’s participation has terminated pursuant to Sections 12 or 13. The option will expire on the last day of the Offering Period. 

10. Exercise of Option. 

10.1 Automatic Exercise. Unless a Participant’s participation in this Plan has terminated as provided in Sections 12 and 13,
his or her option for the purchase of shares of Common Stock will be exercised automatically on the Exercise Date, and the maximum number of full shares of Common Stock subject to the option will be purchased for such Participant at the applicable
Purchase Price with the accumulated Contributions from his or her account. No fractional shares of Common Stock will be purchased; any Contributions accumulated in a Participant’s account, which are not sufficient to purchase a full share will
be retained in the Participant’s account for the subsequent Purchase Period or Offering Period, as applicable, subject to earlier termination of the Participant’s participation in this Plan as provided in Sections 12 or 13. Any other
funds left over in a Participant’s account after the Exercise Date will be returned to the Participant. During a Participant’s lifetime, a Participant’s option to purchase shares of Common Stock under this Plan is exercisable only by
him or her. 
 10.2 Pro Rata Allocations. If the Administrator determines that, on a given Exercise Date, the number of shares of
Common Stock with respect to which options are to be exercised may exceed (a) the number of shares of Common Stock that were available for sale under this Plan on the Enrollment Date of the applicable Offering Period, or (b) the number of
shares of Common Stock available for sale under this Plan on such Exercise Date, the Administrator may in its sole discretion (x) provide that the Company will make a pro rata allocation of the shares of


  
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Common Stock available for purchase on such Enrollment Date or Exercise Date, as applicable, in as uniform a manner as will be practicable and as it will determine in its sole discretion to be
equitable among all Participants exercising options to purchase Common Stock on such Exercise Date, and continue all Offering Periods then in effect or (y) provide that the Company will make a pro rata allocation of the shares of Common Stock
available for purchase on such Enrollment Date or Exercise Date, as applicable, in as uniform a manner as will be practicable and as it will determine in its sole discretion to be equitable among all participants exercising options to purchase
Common Stock on such Exercise Date, and terminate any or all Offering Periods then in effect pursuant to Section 18. The Company may make a pro rata allocation of the shares of Common Stock available on the Enrollment Date of any applicable
Offering Period pursuant to the preceding sentence, notwithstanding any authorization of additional shares of Common Stock for issuance under this Plan by the Company’s stockholders subsequent to such Enrollment Date. 

11. Delivery. As soon as reasonably practicable after each Exercise Date on which a purchase of shares of Common Stock occurs, the
Company will arrange the delivery to each Participant of the shares of Common Stock purchased upon exercise of his or her option in a form determined by the Administrator (in its sole discretion) and pursuant to rules established by the
Administrator. The Company may permit or require that shares of Common Stock be deposited directly with a broker designated by the Company or with a trustee or designated agent of the Company, and the Company may utilize electronic or automated
methods of share transfer. The Company may require that shares of Common Stock be retained with such broker, trustee or agent for a designated period of time or may establish other procedures to permit tracking of disqualifying dispositions or other
dispositions of such shares. No Participant will have any voting, dividend, or other stockholder rights with respect to shares of Common Stock subject to any option granted under this Plan until such shares have been purchased and delivered to the
Participant as provided in this Section 11. 
 12. Withdrawal. 

12.1 Withdrawal Procedures. A Participant may withdraw all but not less than all the Contributions credited to his or her account and
not yet used to exercise his or her option under this Plan at any time by (a) submitting to the Company’s stock administration office (or its designee) a written notice of withdrawal in the form determined by the Administrator for such
purpose (which may be similar to the form attached hereto as Exhibit B), or (b) following an electronic or other withdrawal procedure determined by the Administrator. The Administrator may set
forth a deadline of when a withdrawal must occur to be effective prior to a given Exercise Date in accordance with policies it may approve from time to time. All of the Participant’s Contributions credited to his or her account will be paid to
such Participant as soon as administratively practicable after receipt of notice of withdrawal and such Participant’s option for the Offering Period will be automatically terminated, and no further Contributions for the purchase of shares of
Common Stock will be made for such Offering Period. If a Participant withdraws from an Offering Period, Contributions will not resume at the beginning of the succeeding Offering Period, unless the Participant
re-enrolls in this Plan in accordance with the provisions of Section 7. 

  
 -12- 












 12.2 No Effect on Future Participation. A Participant’s withdrawal from an
Offering Period will not have any effect upon his or her eligibility to participate in any similar plan that may hereafter be adopted by the Company or in succeeding Offering Periods that commence after the termination of the Offering Period from
which the Participant withdraws. 
 13. Termination of Employment. Upon a Participant’s ceasing to be an Eligible Employee, for
any reason, he or she will be deemed to have elected to withdraw from this Plan and the Contributions credited to such Participant’s account during the Offering Period but not yet used to purchase shares of Common Stock under this Plan will be
returned to such Participant, or, in the case of his or her death, to the person or persons entitled thereto, and such Participant’s option will be automatically terminated. Unless determined otherwise by the Administrator in a manner that,
with respect to an Offering under the 423 Component, is permitted by, and compliant with, Code Section 423, a Participant whose employment transfers between entities through a termination with an immediate rehire (with no break in service)
by the Company or a Designated Company will not be treated as terminated under this Plan; however, if a Participant transfers from an Offering under the 423 Component to the Non-423 Component, the
exercise of the option will be qualified under the 423 Component only to the extent it complies with Code Section 423; further, no Participant will be deemed to switch from an Offering under the
Non-423 Component to an Offering under the 423 Component or vice versa unless (and then only to the extent) such switch would not cause the 423 Component or any option thereunder to fail to
comply with Code Section 423. 
 14. Section 409A. This Plan is intended to be exempt from the application of
Section 409A, and, to the extent not exempt, is intended to comply with Section 409A and any ambiguities herein will be interpreted to so be exempt from, or comply with, Section 409A. In furtherance of the foregoing and
notwithstanding any provision in this Plan to the contrary, if the Administrator determines that an option granted under this Plan may be subject to Section 409A or that any provision in this Plan would cause an option under this Plan to be
subject to Section 409A, the Administrator may amend the terms of this Plan or of an outstanding option granted under this Plan, or take such other action the Administrator determines is necessary or appropriate, in each case, without the
Participant’s consent, to exempt any outstanding option or future option that may be granted under this Plan from or to allow any such options to comply with Section 409A, but only to the extent any such amendments or action by the
Administrator would not violate Section 409A. Notwithstanding the foregoing, the Company and any of its Parent or Subsidiaries will have no liability, obligation or responsibility to reimburse, indemnify, or hold harmless a Participant or any
other party if the option to purchase Common Stock under this Plan that is intended to be exempt from or compliant with Section 409A is not so exempt or compliant or for any action taken by the Administrator with respect thereto. The Company
makes no representation that the option to purchase Common Stock under this Plan is compliant with Section 409A. 
 15. Rights as
Stockholder. Until the shares of Common Stock are issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), a Participant will have only the rights of an unsecured creditor
with respect to such shares, and no right to vote or receive dividends or any other rights as a stockholder will exist with respect to such shares. Shares of Common Stock to be delivered to a Participant under this Plan will be registered in the
name of the Participant or, if so required under Applicable Laws, in the name of the Participant and his or her spouse. 

  
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 16. Transferability. Neither Contributions credited to a Participant’s account
nor any rights with regard to the exercise of an option or to receive shares of Common Stock under this Plan may be assigned, transferred, pledged or otherwise disposed of in any way (other than by will or the laws of descent and distribution) by
the Participant. Any such attempt at assignment, transfer, pledge or other disposition will be without effect, except that the Company may treat such act as an election to withdraw funds from an Offering Period in accordance with Section 12.

 17. Adjustments, Dissolution, Liquidation, Merger or Change in Control. 

17.1 Adjustments. In the event that any dividend or other distribution (whether in the form of cash, Common Stock, other securities, or
other property), recapitalization, stock split, reverse stock split, reorganization, merger, consolidation, split-up, spin-off, combination, reclassification,
repurchase, or exchange of Common Stock or other securities of the Company, or other change in the corporate structure of the Company affecting the Common Stock occurs (other than any ordinary dividends or other ordinary distributions), the
Administrator, in order to prevent diminution or enlargement of the benefits or potential benefits intended to be made available under this Plan, will adjust the number and class of common stock that may be delivered under this Plan, the Purchase
Price per share, the class and the number of shares of common stock covered by each option under this Plan that has not yet been exercised, and the numerical share limits of Sections 3 and 9.1. 

17.2 Dissolution or Liquidation. In the event of the proposed dissolution or liquidation of the Company, any Offering Period then in
progress will be shortened by setting a New Exercise Date, and will terminate immediately prior to the consummation of such proposed dissolution or liquidation, unless provided otherwise by the Administrator. The New Exercise Date will be before the
date of the Company’s proposed dissolution or liquidation. The Administrator will notify each Participant in writing or electronically, prior to the New Exercise Date, that the Exercise Date for the Participant’s option has been changed to
the New Exercise Date and that the Participant’s option will be exercised automatically on the New Exercise Date, unless prior to such date the Participant has withdrawn from the Offering Period as provided in Section 12 (or, prior to such
New Exercise Date, Participant’s participation has terminated as provided in Section 13). 
 17.3 Merger or Change in
Control. In the event of a merger of the Company with or into another corporation or other entity or Change in Control, each outstanding option will be assumed or an equivalent option substituted by the successor corporation or a Parent or
Subsidiary of the successor corporation. In the event that the successor corporation refuses to assume or substitute for the option, the Offering Period with respect to which such option relates will be shortened by setting a New Exercise Date on
which such Offering Period will end. The New Exercise Date will occur before the date of the Company’s proposed merger or Change in Control. The Administrator will notify each Participant in writing or electronically prior to the New Exercise
Date, that the Exercise Date for the Participant’s option has been changed to the New Exercise Date and that the Participant’s option will be exercised automatically on the New Exercise Date, unless prior to such date the Participant has
withdrawn from the Offering Period as provided in Section 12 (or, prior to such New Exercise Date, Participant’s participation has terminated as provided in Section 13). 

  
 -14- 












 18. Amendment or Termination. 

18.1 Amendment, Suspension, Termination. The Administrator, in its sole discretion, may amend, alter, suspend, or terminate this Plan,
or any part thereof, at any time and for any reason. If this Plan is terminated, the Administrator, in its discretion, may elect to terminate all outstanding Offering Periods either immediately or upon completion of the purchase of shares of Common
Stock on the next Exercise Date (which may be sooner than originally scheduled, if determined by the Administrator in its discretion), or may elect to permit Offering Periods to expire in accordance with their terms (and subject to any adjustment
pursuant to Section 17). If the Offering Periods are terminated prior to expiration, all amounts then credited to Participants’ accounts that have not been used to purchase shares of Common Stock will be returned to the Participants
(without interest thereon, except as otherwise required under Applicable Laws, as further set forth in Section 22) as soon as administratively practicable. 

18.2 Certain Administrator Changes. Without stockholder consent and without limiting Section 18.1, the Administrator will be
entitled to change the Offering Periods and any Purchase Periods, designate separate Offerings, limit the frequency or number of changes in the amount withheld during an Offering Period, establish the exchange rate applicable to amounts withheld in
a currency other than U.S. dollars, permit Contributions in excess of the amount designated by a Participant in order to adjust for delays or mistakes in the Company’s processing of properly completed Contribution elections, establish
reasonable waiting and adjustment periods or accounting and crediting procedures to ensure that amounts applied toward the purchase of Common Stock for each Participant properly correspond with Contribution amounts, and establish such other
limitations or procedures as the Administrator determines in its sole discretion advisable that are consistent with this Plan. 
 18.3
Changes Due to Accounting Consequences. In the event the Administrator determines that the ongoing operation of this Plan may result in unfavorable financial accounting consequences, the Administrator may, in its discretion and, to the extent
necessary or desirable, modify, amend or terminate this Plan to reduce or eliminate such accounting consequence including: 
 (a) amending
this Plan to conform with the safe harbor definition under the Financial Accounting Standards Board Accounting Standards Codification Topic 718 (or any successor thereto), including with respect to an Offering Period underway at the time; 

(b) altering the Purchase Price for any Purchase Period or Offering Period including a Purchase Period or Offering Period underway at the
time of the change in Purchase Price; 
 (c) shortening any Purchase Period or Offering Period by setting a New Exercise Date, including a
Purchase Period or Offering Period underway at the time of the Administrator action; 
 (d) reducing the maximum percentage of Compensation
a Participant may elect to set aside as Contributions; and 
 (e) reducing the maximum number of shares of Common Stock a Participant may
purchase during any Purchase Period or Offering Period. 
 Such modifications or amendments will not require stockholder approval or the
consent of any Plan Participants. 

  
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 19. Conditions Upon Issuance of Shares. 

19.1 Legal Compliance. Shares of Common Stock will not be issued with respect to an option unless the exercise of such option and the
issuance and delivery of such shares pursuant thereto will comply with Applicable Laws and will be further subject to the approval of counsel for the Company with respect to such compliance. 

19.2 Investment Representations. As a condition to the exercise of an option, the Company may require the person exercising such option
to represent and warrant at the time of any such exercise that the shares are being purchased only for investment and without any present intention to sell or distribute such shares if, in the opinion of counsel for the Company, such a
representation is required. 
 20. Term of Plan. This Plan will become effective upon the latest to occur of (a) its adoption by
the Board, (b) its approval by the Company’s stockholders, or (c) the time as of immediately prior to the Closing. This Plan will continue in effect for a term of 20 years, unless sooner terminated under Section 18. 

21. Stockholder Approval. This Plan will be subject to approval by the stockholders of the Company within 12 months after the date this
Plan is adopted by the Board. Such stockholder approval will be obtained in the manner and to the degree required under Applicable Laws. 

22. Interest. No interest will accrue on the Contributions of a participant in this Plan, except as may be required by Applicable Laws,
as determined by the Company, and if so required by the laws of a particular jurisdiction, will apply, with respect to Offerings under the 423 Component, to all Participants in the relevant Offering, except to the extent otherwise permitted by
U.S. Treasury Regulations Section 1.423-2(f). 
 23. No Effect on Employment. Neither
this Plan nor any option under this Plan will confer upon any Participant any right with respect to continuing the Participant’s employment with the Company or its Subsidiaries or Parents, as applicable, nor will they interfere in any way with
the Participant’s right or the right of the Company and its Subsidiaries or Parents, as applicable, to terminate such employment relationship at any time, free from any liability or any claim under this Plan. 

24. Reports. Individual accounts will be maintained for each Participant in this Plan. Statements of account will be given to
participating Eligible Employees at least annually, which statements will set forth the amounts of Contributions, the Purchase Price, the number of shares of Common Stock purchased and the remaining cash balance, if any. 

25. Notices. All notices or other communications by a Participant to the Company under or in connection with this Plan will be deemed
to have been duly given when received in the form and manner specified by the Company at the location, or by the person, designated by the Company for the receipt thereof. 

  
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 26. Legal Construction. 

26.1 Severability. If any provision of this Plan is or becomes or is deemed to be invalid, illegal, or unenforceable for any reason in
any jurisdiction or as to any Participant, such invalidity, illegality, or unenforceability will not affect the remaining parts of this Plan, and this Plan will be construed and enforced as to such jurisdiction or Participant as if the invalid,
illegal, or unenforceable provision had not been included. 
 26.2 Governing Law. This Plan will be governed by, and construed in
accordance with, the laws of the State of California, but without regard to its conflict of law provisions. 
 26.3 Headings.
Headings are provided herein for convenience only, and will not serve as a basis for interpretation of this Plan. 
 27. Compliance with
Applicable Laws. The terms of this Plan are intended to comply with all Applicable Laws and will be construed accordingly. 
 28.
Automatic Transfer to Low Price Offering Period. Unless determined otherwise by the Administrator, this Section 28 applies to an Offering Period to the extent such Offering Period provides for more than one Exercise Date within such
Offering Period. To the extent permitted by Applicable Laws, if the Fair Market Value of a share of Common Stock on any Exercise Date in an Offering Period is less than the Fair Market Value of a share of Common Stock on the Enrollment Date of such
Offering Period, then all Participants in such Offering Period will be withdrawn automatically from such Offering Period immediately after the exercise of their option on such Exercise Date and automatically
re-enrolled in the immediately following Offering Period as of the first day thereof. 
 29.
Construction; Interpretation. The titles of the Sections of this Plan are for convenience only and are not to be considered in construing this Plan. In this Plan, unless otherwise specified: (a) “includes” and “including”
shall mean respectively includes and including without limitation; (b) the word “or” shall not be deemed to be used in the exclusive sense and shall instead be used in the inclusive sense to mean “or”; (c) words denoting any
gender shall include all genders; and (d) except as otherwise indicated, all references in this Plan to a “Section” are intended to refer to a Section of this Plan. 

  
 -17- 












 EXHIBIT A 

APEXIGEN, INC. 
 2022
EMPLOYEE STOCK PURCHASE PLAN 
 SUBSCRIPTION AGREEMENT 
  

			
	_____ Original Application	  	Offering Date: _________________
		
	_____ Change in Payroll Deduction Rate	  	

 1. ____________________ hereby elects to participate in the Apexigen, Inc. 2022 Employee Stock Purchase
Plan (the “Plan”) and subscribes to purchase shares of the Company’s Common Stock in accordance with this Subscription Agreement and the Plan. Any capitalized terms not specifically defined in this Subscription Agreement will
have the meaning ascribed to them under the Plan. 
 2. I hereby authorize and consent to payroll deductions from each paycheck in the
amount of ____% of my Compensation on each payday (from 0% to 15%) during the Offering Period in accordance with the Plan. (Please note that no fractional percentages are permitted.) I understand that only my first election to decrease the rate of
my payroll deductions to 0% may be applied with respect to an ongoing Offering Period in accordance with the terms of the Plan, and (a) any subsequent election to decrease the rate of my payroll deductions during the same Offering Period or
(b) any election to increase the rate of my payroll deductions during any Offering Period will not be applied to the ongoing Offering Period. 

3. I understand that said payroll deductions will be accumulated for the purchase of shares of Common Stock at the applicable Purchase Price
determined in accordance with the Plan. I understand that if I do not withdraw from an Offering Period, any accumulated payroll deductions will be used to automatically exercise my option and purchase Common Stock under the Plan. I further
understand that if I am outside of the U.S., my payroll deductions will be converted to U.S. dollars at an exchange rate selected by the Company on the purchase date. 

4. I have received a copy of the complete Plan and its accompanying prospectus. I understand that my participation in the Plan is in all
respects subject to the terms of the Plan. 
 5. Shares of Common Stock purchased for me under the Plan should be issued in the name(s) of
_____________ (Eligible Employee or Eligible Employee and spouse only). 
 6. If I am a U.S. taxpayer, I understand that if I dispose of any
shares received by me pursuant to the Plan within 2 years after the Offering Date (the first day of the Offering Period during which I purchased such shares) or 1 year after the Exercise Date, I will be treated for federal income tax purposes as
having received ordinary income at the time of such disposition in an amount equal to the excess of the fair market value of the shares at the time such shares were purchased by me over the price that I paid for the shares. I hereby agree to
notify the Company in writing within 30 days after the date of any disposition of my shares and I will make adequate provision for federal, state or other tax withholding obligations, if any, which arise upon the disposition of the Common
Stock. The Company may, but will not be obligated to, withhold from my compensation the amount necessary to meet any applicable 

  
 -18- 












 
withholding obligation including any withholding necessary to make available to the Company any tax deductions or benefits attributable to sale or early disposition of Common Stock by me. If I
dispose of such shares at any time after the expiration of the 2-year and 1-year holding periods, I understand that I will be treated for federal income tax purposes as
having received income only at the time of such disposition, and that such income will be taxed as ordinary income only to the extent of an amount equal to the lesser of (a) the excess of the fair market value of the shares at the time of such
disposition over the purchase price which I paid for the shares, or (b) 15% of the fair market value of the shares on the first day of the Offering Period. The remainder of the gain, if any, recognized on such disposition will be taxed as
capital gain. 
 7. For employees that may be subject to tax in non U.S. jurisdictions, I acknowledge and agree that, regardless of any
action taken by the Company or any Designated Company with respect to any or all income tax, social security, social insurances, National Insurance Contributions, payroll tax, fringe benefit, or other
tax-related items related to my participation in the Plan and legally applicable to me including in connection with the grant of such options, the purchase or sale of shares of Common Stock acquired under the
Plan or the receipt of any dividends on such shares (“Tax-Related Items”), the ultimate liability for all Tax-Related Items is and remains my
responsibility and may exceed the amount actually withheld by the Company or a Designated Company. Furthermore, I acknowledge that the Company or any Designated Company (a) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the options under the Plan and (b) do not commit to and are under no obligation to structure the terms of the grant of options or any aspect of my
participation in the Plan to reduce or eliminate my liability for Tax-Related Items or achieve any particular tax result. Further, if I have become subject to tax in more than one jurisdiction between the date
of my enrollment and the date of any relevant taxable or tax withholding event, as applicable, I acknowledge that the Company or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction. 
 Prior to the purchase of shares of Common Stock under
the Plan or any other relevant taxable or tax withholding event, as applicable, I agree to make adequate arrangements satisfactory to the Company or the applicable Designated Company to satisfy all Tax-Related
Items. In this regard, I authorize the Company or the applicable Designated Company, or their respective agents, at their discretion, to satisfy any applicable withholding obligations with regard to all
Tax-Related Items by one or a combination of the following: (a) withholding from my wages or Compensation paid to me by the Company or the applicable Designated Company; or (b) withholding from
proceeds of the sale of the shares of Common Stock purchased under the Plan either through a voluntary sale or through a mandatory sale arranged by the Company (on my behalf pursuant to this authorization). Depending on the withholding method, the
Company may withhold or account for Tax-Related Items by considering applicable maximum withholding rates, in which case I will receive a refund of any over-withheld
amount in cash and will have no entitlement to the Common Stock equivalent. 
 Finally, I agree to pay to the Company or the applicable
Designated Company any amount of Tax-Related Items that the Company or the applicable Designated Company may be required to withhold as a result of my participation in the Plan that cannot be satisfied by the
means previously described. The Company may refuse to purchase shares of Common Stock under the Plan on my behalf or refuse to issue or deliver the shares or the proceeds of the sale of shares if I fail to comply with my obligations in connection
with the Tax-Related Items. 

  
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 8. By electing to participate in the Plan, I acknowledge, understand and agree that: 

(a) the Plan is established voluntarily by the Company, it is discretionary in nature and it may be modified, amended, suspended or terminated
by the Company at any time, to the extent provided for in the Plan; 
 (b) all decisions with respect to future grants under the Plan, if
applicable, will be at the sole discretion of the Company; 
 (c) the grant of options under the Plan will not create a right to employment
or be interpreted as forming or amending an employment or service contract with the Company, or any Designated Company, and will not interfere with the ability of the Company or any Designated Company, as applicable, to terminate my employment (if
any); 
 (d) I am voluntarily participating in the Plan; 

(e) the options granted under the Plan and the shares of Common Stock underlying such options, and the income and value of same, are not
intended to replace any pension rights or compensation; 
 (f) the options granted under the Plan and the shares of Common Stock underlying
such options, and the income and value of same, are not part of my normal or expected compensation for any purpose, including calculating any severance, resignation, termination, redundancy, dismissal, end-of-service payments, bonuses, long-service awards, pension or retirement benefits or similar payments; 

(g) the future value of the shares of Common Stock offered under the Plan is unknown, indeterminable and cannot be predicted with certainty;

 (h) the shares of Common Stock that I acquire under the Plan may increase or decrease in value, even below the Purchase Price; 

(i) no claim or entitlement to compensation or damages will arise from the forfeiture of options granted to me under the Plan as a result of
the termination of my status as an Eligible Employee (for any reason whatsoever, and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where I am employed or the terms of my employment agreement, if any)
and, in consideration of the grant of options under the Plan to which I am otherwise not entitled, I irrevocably agree never to institute a claim against the Company, or any Designated Company, waive my ability, if any, to bring such claim, and
release the Company, and any Designated Company from any such claim that may arise; if, notwithstanding the foregoing, any such claim is allowed by a court of competent jurisdiction, I will be deemed irrevocably to have agreed to not to pursue such
claim and agree to execute any and all documents necessary to request dismissal or withdrawal of such claim; and 

  
 -20- 












 (j) in the event of the termination of my status as an Eligible Employee (for any reason
whatsoever, whether or not later found to be invalid or in breach of employment laws in the jurisdiction where I am employed or the terms of my employment agreement, if any), my right to participate in the Plan and any options granted to me under
the Plan, if any, will terminate effective as of the date that I am no longer actively employed by the Company or one of its Designated Companies and, in any event, will not be extended by any notice period mandated under the employment laws in the
jurisdiction in which I am employed or the terms of my employment agreement, if any (e.g., active employment would not include a period of “garden leave” or similar period pursuant to the employment laws in the jurisdiction
in which I am employed or the terms of my employment agreement, if any); the Company will have the exclusive discretion to determine when I am no longer actively employed for purposes of my participation in the Plan (including whether I may still be
considered to be actively employed while on a leave of absence). 
 9. I understand that the Company or any Designated Company may
collect, where permissible under applicable law certain personal information about me, including my name, home address and telephone number, date of birth, social insurance number or other identification number, salary, nationality, job title, any
shares of Common Stock or directorships held in the Company, details of all options granted under the Plan or any other entitlement to shares of Common Stock awarded, canceled, exercised, vested, unvested or outstanding in my favor
(“Data”), for the exclusive purpose of implementing, administering and managing the Plan. I understand that Company may transfer my Data to the United States, which is not considered by the European Commission to have
data protection laws equivalent to the laws in my country. I understand that the Company will transfer my Data to its designated broker, or such other stock plan service provider as may be selected by the Company in the future, which is assisting
the Company with the implementation, administration and management of the Plan. I understand that the recipients of the Data may be located in the United States or elsewhere, and that a recipient’s country of operation (e.g., the United States)
may have different, including less stringent, data privacy laws that the European Commission or my jurisdiction does not consider to be equivalent to the protections in my country. I understand that I may request a list with the names and addresses
of any potential recipients of the Data by contacting my local human resources representative. I authorize the Company, the Company’s designated broker and any other possible recipients which may assist the Company with implementing,
administering and managing the Plan to receive, possess, use, retain and transfer the Data, in electronic or other form, for the sole purpose of implementing, administering and managing my participation in the Plan. I understand that Data will be
held only as long as is necessary to implement, administer and manage my participation in the Plan. I understand that that I may, at any time, view Data, request additional information about the storage and processing of Data, require any necessary
amendments to Data or refuse or withdraw the consents herein, in any case without cost, by contacting in writing my local human resources representative. Further, I understand that I am providing the consents herein on a purely voluntary basis. If I
do not consent, or if I later seek to revoke my consent, my employment status or career with the Company or any Designated Company will not be adversely affected; the only adverse consequence of refusing or withdrawing my consent is that the Company
would not be able to grant me options under the Plan or other equity awards, or administer or maintain such awards. Therefore, I understand that refusing or withdrawing my consent may affect my ability to participate in the Plan. For more
information on the consequences of my refusal to consent or withdrawal of consent, I understand that I may contact my local human resources representative. 

  
 -21- 












 If I am an employee outside the U.S., I understand that in accordance with applicable
law, I have the right to access, and to request a copy of, the Data held about me. I also understand that I have the right to discontinue the collection, processing, or use of my Data, or supplement, correct, or request deletion of my Data. To
exercise my rights, I may contact my local human resources representative. 
 I hereby explicitly and unambiguously consent to the
collection, use and transfer, in electronic or other form, of my personal data as described herein and any other Plan materials by and among, as applicable, the Company and its Subsidiaries for the exclusive purpose of implementing, administering
and managing my participation in the Plan. I understand that my consent will be sought and obtained for any processing or transfer of my data for any purpose other than as described in the enrollment form and any other plan materials. 

10. If I have received the Subscription Agreement or any other document related to the Plan translated into a language other than English and
if the meaning of the translated version is different than the English version, the English version will control, subject to applicable laws. 

11. The provisions of the Subscription Agreement and these appendices are severable and if any one or more provisions are determined to be
illegal or otherwise unenforceable, in whole or in part, the remaining provisions nevertheless will be binding and enforceable. 
 12.
Notwithstanding any provisions in this Subscription Agreement, I understand that if I am working or resident in a country other than the United States, my participation in the Plan also will be subject to the additional terms and conditions set
forth on Appendix A and any special terms and conditions for my country set forth on Appendix A. Moreover, if I relocate to one of the countries included in Appendix A, the special terms and conditions for such country will apply to me to the extent
the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. Appendix A constitutes part of this Subscription Agreement and the provisions of this Subscription Agreement
govern each Appendix (to the extent not superseded or supplemented by the terms and conditions set forth in the applicable Appendix). 
 13.
I hereby agree to be bound by the terms of the Plan. The effectiveness of this Subscription Agreement is dependent upon my eligibility to participate in the Plan. 

[Signature page follows.] 

  
 -22- 













			
	 Employee’s Social
	 	
	 Security Number
	 	
	 (for U.S.-based employees):
	 	 
		
	 Employee’s Address:
	 	 
		
		 	 
		
		 	 

 I UNDERSTAND THAT THIS SUBSCRIPTION AGREEMENT WILL REMAIN IN EFFECT THROUGHOUT SUCCESSIVE OFFERING PERIODS
UNLESS TERMINATED BY ME. 

									
					
	Dated:	 	 	 		 		 	 
		 		 		 		 	 Signature of Employee



  
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 EXHIBIT B 

APEXIGEN, INC. 

2022 EMPLOYEE STOCK PURCHASE PLAN 

NOTICE OF WITHDRAWAL 
 The
undersigned Participant in the Offering Period of the Apexigen, Inc. 2022 Employee Stock Purchase Plan (the “Plan”) that began on ____________, ______ (the “Offering Date”) hereby notifies the Company that he
or she hereby withdraws from the Offering Period. He or she hereby directs the Company to pay to the undersigned as promptly as practicable all the payroll deductions credited to his or her account with respect to such Offering Period. The
undersigned understands and agrees that his or her option for such Offering Period will be terminated automatically. The undersigned understands further that no further payroll deductions will be made for the purchase of shares in the current
Offering Period and the undersigned will be eligible to participate in succeeding Offering Periods only by delivering to the Company a new Subscription Agreement. Capitalized terms not otherwise defined herein will have the meaning ascribed to them
under the Plan. 
  

									
		 		 	Name and Address of Participant:
				
		 		 		 	 
				
		 		 		 	 
				
		 		 		 	 
				
		 		 		 	Signature:
				
		 		 		 	 
					
		 		 		 	Date:	 	 


  
 -24-