Document:

EX-10.3

 Exhibit 10.3 

SPONSOR SUPPORT AGREEMENT 

This SPONSOR SUPPORT AGREEMENT (this “Agreement”), dated as of March 17, 2022, is entered into by and among Brookline
Capital Holdings, LLC, a Delaware limited liability company (the “Sponsor”), Brookline Capital Acquisition Corp., a Delaware corporation (“BCAC”), and Apexigen, Inc., a Delaware corporation (the
“Company”). 
 RECITALS 

WHEREAS, concurrently herewith, the Company, Project Barolo Merger Sub, LLC, a Delaware limited liability company (“Merger
Sub”), and BCAC are entering into a Business Combination Agreement (as amended, supplemented, restated or otherwise modified from time to time, the “BCA”), pursuant to which (and subject to the terms and conditions set
forth therein) Merger Sub will merge with and into the Company (the “Merger”), with the Company surviving the Merger as a wholly owned subsidiary of BCAC; 

WHEREAS, capitalized terms used but not otherwise defined in this Agreement shall have the meanings ascribed to them in the BCA; and

 WHEREAS, as a condition and inducement to the willingness of BCAC and the Company to enter into the BCA, BCAC, the Company and the
Sponsor are entering into this Agreement. 
 AGREEMENT 

NOW, THEREFORE, in consideration of the foregoing and the mutual covenants and agreements set forth herein, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound hereby, the Sponsor, BCAC and the Company hereby agree as follows: 

1. Voting Agreement. The Sponsor hereby unconditionally and irrevocably agrees that during the period from the date hereof through the
Termination Date as determined in accordance with Section 24, at the BCAC Stockholders’ Meeting or at any other meeting of the stockholders of BCAC (whether annual or special and whether or not an adjourned or
postponed meeting, however called and including any adjournment or postponement thereof) and in connection with any action by written consent of the stockholders of BCAC requested by the BCAC Board or undertaken as contemplated by the Transactions,
the Sponsor shall: 
 (a) when such meeting is held, appear at such meeting or otherwise cause all shares of BCAC Common Stock or any other
voting securities of BCAC which it holds, owns or is entitled to vote, whether as shares or as a constituent part of a unit of securities and whether owned as of the date of or later acquired (the “Sponsor Shares”), to be counted as
present thereat for the purpose of establishing a quorum; 

 (b) vote (or execute and return an action by written consent), or cause to be voted at such
meeting (or validly execute and return and cause such consent to be granted with respect to), all of the Sponsor Shares in favor of (i) the approval and adoption of the BCA and approval of the Merger and all other transactions contemplated by
the BCA and (ii) against any action, agreement or transaction or proposal that would result in a breach of any covenant, representation or warranty or any other obligation or agreement of BCAC under the BCA or that would reasonably be expected
to result in the failure of the Merger from being consummated and (iii) each of the proposals and any other matters necessary or reasonably requested by BCAC for consummation of the Merger and the other transactions contemplated by the BCA; and

 (c) vote (or execute and return an action by written consent), or cause to be voted at such meeting (or validly execute and return and
cause such consent to be granted with respect to), all of the Sponsor Shares against (i) any Business Combination Proposal other than with the Company and (ii) any other action that would reasonably be expected to (x) materially
impede, interfere with, delay, postpone or adversely affect the Merger or any of the other transactions contemplated by the BCA, or (y) result in a breach of any covenant, representation or warranty or other obligation or agreement of the
Sponsor contained in this Agreement. 
 2. Sponsor Promote Adjustment. In connection with the consummation of the Transactions,
Sponsor agrees that, subject to the satisfaction or waiver of each of the conditions to Closing set forth in Sections 8.01, 8.02 and 8.03 of the BCA, immediately prior to the Effective Time, in the event the BCAC Related Funds
Amount at Closing that are available to the Company are less than $20,000,000, that number of Sponsor Shares (the “Surrendered Shares”) equal to (x) one (1) minus the quotient of the BCAC Related Funds Amount divided by
$20,000,000, multiplied by (y) one-third (1/3) of the total number of Sponsor Shares, shall be deemed automatically forfeited and cancelled without any further actions by the Sponsor or any other Person,
and such Surrendered Shares will be recorded as cancelled by the Company. 
 3. Transfer of Shares. Except as otherwise contemplated
by the BCA or this Agreement, the Sponsor agrees that prior to the Termination Date it shall not, without the consent of the Company, directly or indirectly, (a) offer for sale, sell, assign, transfer (including by operation of law), create any
lien or pledge, dispose of or otherwise encumber any of the Sponsor Shares (any of the forgoing, a “Transfer”) or otherwise agree to do any of the foregoing, (b) deposit any Sponsor Shares into a voting trust or enter into a voting
agreement or arrangement or grant any proxy or power of attorney with respect thereto that is inconsistent with this Agreement or (c) enter into any contract, option or other arrangement or undertaking requiring the Transfer of any Sponsor
Shares. The Sponsor expressly agrees to continue to comply with the restrictions on transfer of the Sponsor Shares set forth in Section 7 of that certain side letter between the Sponsor and BCAC dated January 28, 2021, and neither the
Company nor BCAC shall agree to any waiver, amendment or modification of such provisions without the prior written consent of the Company. Notwithstanding the foregoing, this Section 3 shall also not prohibit a Transfer of Sponsor Shares by
Sponsor to an affiliate of Sponsor; provided, that such Transfer shall be permitted only if, prior to or in connection with such Transfer, the transferee agrees in writing, reasonably satisfactory in form and substance to the Company, to assume all
of the obligations of Sponsor hereunder and to be bound by the terms of this Agreement. 
 4. No Solicitation of Transactions. The
Sponsor agrees prior to the Termination Date not to directly or indirectly, through any of its affiliates or Representatives, (a) solicit, initiate or knowingly encourage (including by furnishing information) the submission of, or participate
in any discussions or negotiations with, any Person (other than the Company or its affiliates or 

  
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Representatives), concerning, relating to or which is intended or is reasonably likely to give rise to or result in, a Business Combination Proposal in respect of BCAC other than with the
Company. Sponsor shall, and shall cause its affiliates and Representatives to, immediately cease any and all existing discussions or negotiations with any Person (other than with the Company, its stockholders and their respective affiliates and
Representatives) conducted prior to the date hereof with respect to, or which is reasonably likely to give rise to or result in, a Business Combination Proposal in respect of BCAC. If the Sponsor or any of its affiliates or Representatives receives
any inquiry or proposal with respect to a Business Combination Proposal in respect of BCAC, then Sponsor shall promptly (and in no event later than twenty-four (24) hours after the Sponsor becomes aware of such inquiry or proposal) notify such
Person in writing that BCAC is subject to an exclusivity agreement with respect to the Merger that prohibits Sponsor from considering such inquiry or proposal and, in such event, Sponsor shall also promptly notify the Company of such facts and
circumstances (provided that Sponsor shall not be obligated to provide such notice in violation of any obligation of confidentiality owed to any third party or any Law). 

5. Representations and Warranties of the Sponsor. The Sponsor hereby represents and warrants to BCAC and the Company as follows: 

(a) The Sponsor is the only record and a beneficial owner (within the meaning of Rule 13d-3 under the
Exchange Act) of, and has good, valid and marketable title to, the Sponsor Shares (which, as of the date hereof, consists of 1,428,250 shares of BCAC Common Stock), free and clear of Liens other than as created by this Agreement or Sponsor’s
organizational documents or the organizational documents of BCAC (including, without limitation, for the purposes hereof, any agreement between or among stockholders of BCAC). 

(b) The Sponsor (i) has full voting power, full power of disposition and full power to issue instructions with respect to the matters set
forth herein, in each case, with respect to the Sponsor Shares, (ii) has not entered into any voting agreement or voting trust with respect to any of the Sponsor Shares that is inconsistent with the Sponsor’s obligations pursuant to this
Agreement, (iii) has not granted a proxy or power of attorney with respect to any of the Sponsor Shares that is inconsistent with the Sponsor’s obligations pursuant to this Agreement and (iv) has not entered into any agreement or
undertaking that is otherwise inconsistent with, or would interfere with, or prohibit or prevent it from satisfying, its obligations pursuant to this Agreement. 

(c) The Sponsor (i) is a legal entity duly organized, validly existing and, to the extent such concept is applicable, in good standing
under the Laws of the jurisdiction of its organization and (ii) has all requisite limited liability company or other power and authority and has taken all limited liability company or other action necessary in order to, execute, deliver and
perform its obligations under this Agreement and to consummate the transactions contemplated hereby. This Agreement has been duly executed and delivered by the Sponsor and constitutes a valid and binding agreement of the Sponsor enforceable against
the Sponsor in accordance with its terms, subject to applicable bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and similar Laws affecting creditors’ rights generally and subject, as to enforceability, to general
principles of equity. 

  
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 (d) Other than the filings, notices and reports pursuant to, in compliance with or required
to be made under the Exchange Act, no filings, notices, reports, consents, registrations, approvals, permits, waivers, expirations of waiting periods or authorizations are required to be obtained by the Sponsor from, or to be given by the Sponsor
to, or be made by the Sponsor with, any Governmental Authority in connection with the execution, delivery and performance by the Sponsor of this Agreement, the consummation of the transactions contemplated hereby or the Merger and the other
transactions contemplated by the BCA. 
 (e) The execution, delivery and performance of this Agreement by the Sponsor does not, and the
consummation of the transactions contemplated hereby or the Merger and the other transactions contemplated by the BCA will not, constitute or result in (i) a breach or violation of, or a default under, the limited liability company agreement or
similar governing documents of the Sponsor, (ii) with or without notice, lapse of time or both, a breach or violation of, a termination (or right of termination) of or a default under, the loss of any benefit under, the creation, modification
or acceleration of any obligations under or the creation of a Lien on any of the properties, rights or assets of the Sponsor pursuant to any contract binding upon the Sponsor or (iii) any change in the rights or obligations of any party under
any contract legally binding upon the Sponsor, except, in the case of clause (ii) or (iii) directly above, for any such breach, violation, termination, default, creation, acceleration or change that would not, individually or in the aggregate,
reasonably be expected to prevent or materially delay or impair the Sponsor’s ability to perform its obligations hereunder or to consummate the transactions contemplated hereby, the consummation of the Merger or the other transactions
contemplated by the BCA. 
 (f) As of the date of this Agreement, there is no action, proceeding or investigation pending against the
Sponsor or, to the knowledge of the Sponsor, threatened against the Sponsor that questions the beneficial or record ownership of the Sponsor Shares, the validity of this Agreement or the performance by the Sponsor of its obligations under this
Agreement. 
 (g) The Sponsor understands and acknowledges that each of BCAC and the Company is entering into the BCA in reliance upon the
Sponsor’s execution and delivery of this Agreement and the representations, warranties, covenants and other agreements of the Sponsor contained herein 

6. Further Assurances. From time to time, at either BCAC’s or the Company’s request and without further consideration, the
Sponsor shall execute and deliver such additional documents and take all such further action as may be reasonably necessary or reasonably requested to effect the actions and consummate the transactions contemplated by this Agreement. 

7. Amendment and Modification. This Agreement may not be amended, modified or supplemented in any manner, whether by course of conduct
or otherwise, except by an instrument in writing signed by the Sponsor, BCAC and the Company. 
 8. Waiver. No failure or delay by
any party hereto exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or
privilege. The rights and remedies of the parties hereto hereunder are cumulative and are not exclusive of any rights or remedies which they would otherwise have hereunder. Any agreement on the part of a party hereto to any such waiver shall be
valid only if set forth in a written instrument executed and delivered by such party. 

  
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 9. Notices. All notices and other communications hereunder shall be in writing and
shall be deemed given if delivered personally, by email (with confirmation of receipt) or sent by a nationally recognized overnight courier service to the parties hereto at the following addresses (or at such other address for a party as shall be
specified by like notice made pursuant to this Section 9): 
 if to Sponsor, BCAC or Merger Sub:

 Brookline Capital Acquisition Corp. 

280 Park Avenue, Suite 43W 

New York, NY 10017 

Attention: Samuel P. Wertheimer, Chairman and CEO 

Email: *** 

with a copy to: 

DLA Piper LLP (US) 

1251 Avenue of the Americas 

New York, NY 10020 

Attention: James Kelly; Peter Ekberg 

Email: james.kelly@us.dlapiper.com; peter.ekberg@us.dlapiper.com 

and 

DLA Piper LLP (US) 

555 Mission Street 

Suite 2400 

San Francisco, CA 94105 

Attention: Jeffrey Selman 

Email: jeffrey.selman@us.dlapiper.com 

if to the Company: 

Apexigen, Inc. 

75 Shoreway Road 

Suite C 

San Carlos, CA 94070 

Attention: Xiaodong Yang, MD, PhD, President and CEO; 

                Amy Wong, Senior Vice
President, Finance and Operations 
 Email: *** 

  
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 with a copy to: 

Wilson Sonsini 

650 Mill Page Road 

Palo Alto, CA 94304 

Attention: Kenneth A. Clark; Michael E. Coke; Lance E. Brady 

Email: kclark@wsgr.com; mcoke@wsgr.com; lbrady@wsgr.com 

and with a copy to: 

Wilson Sonsini 

One Market Plaza, Spear Tower, Suite 3300 

San Francisco, CA 94105 

Attention: Robert T. Ishii 

Email: rishii@wsgr.com 

10. Entire Agreement. This Agreement, the BCA and the Transaction Documents constitute the entire agreement and supersede all prior
agreements and understandings, both written and oral, among the parties hereto with respect to the subject matter hereof and thereof. 
 11.
No Third-Party Beneficiaries. The Sponsor hereby agrees that its representations, warranties and covenants set forth herein are solely for the benefit of BCAC and the Company in accordance with and subject to the terms of this Agreement, and
this Agreement is not intended to, and does not, confer upon any person other than the parties hereto any rights or remedies hereunder, including, without limitation, the right to rely upon the representations and warranties set forth herein, and
the parties hereto hereby further agree that this Agreement may only be enforced against, and any action that may be based upon, arise out of or relate to this Agreement, or the negotiation, execution or performance of this Agreement may only be
made against, the persons expressly named as parties hereto. 
 12. Governing Law and Venue. This Agreement shall be governed by,
interpreted under, and construed in accordance with the internal laws of the State of Delaware applicable to agreements made and to be performed within the State of Delaware, without giving effect to any choice-of-law provisions thereof that would compel the application of the substantive laws of any other jurisdiction 

13. Assignment; Successors. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any
of the parties hereto in whole or in part (whether by operation of Law or otherwise) without the prior written consent of the other party, and any such assignment without such consent shall be null and void. This Agreement shall be binding upon,
inure to the benefit of and be enforceable by the parties hereto and their respective successors and permitted assigns. 

  
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 14. No Recourse. Notwithstanding anything to the contrary contained herein or
otherwise, but without limiting any provision in the BCA or any other Transaction Document, this Agreement may only be enforced against, and any claims or causes of action that may be based upon, arise out of or relate to this Agreement, or the
negotiation, execution or performance of this Agreement or the transactions contemplated hereby, may only be made against the entities and Persons that are expressly identified as parties to this Agreement in their capacities as such and no former,
current or future shareholders or stockholders, equity holders, controlling persons, directors, officers, employees, general or limited partners, members, managers, agents or affiliates of any party hereto, or any former, current or future direct or
indirect shareholder or stockholder, equity holder, controlling person, director, officer, employee, general or limited partner, member, manager, agent or affiliate of any of the foregoing (each, a
“Non-Recourse Party”) shall have any liability for any obligations or liabilities of the parties to this Agreement or for any claim (whether in tort, contract or otherwise) based on, in
respect of, or by reason of, the transactions contemplated hereby or in respect of any oral representations made or alleged to be made in connection herewith. Without limiting the rights of any party against the other parties hereto, in no event
shall any party or any of its affiliates seek to enforce this Agreement against, make any claims for breach of this Agreement against, or seek to recover monetary damages from, any Non-Recourse Party. 

15. Specific Performance. Each party acknowledges and agrees that the other parties hereto would be irreparably harmed and would not
have any adequate remedy at law in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached. Accordingly, each party agrees that the other parties hereto shall be
entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement, this being in addition to any other remedy to which such parties are entitled at law or in equity.

 16. Severability. In the event that any provision of this Agreement or the application thereof becomes or is declared by a court
of competent jurisdiction to be illegal, void or unenforceable, the remainder of this Agreement will continue in full force and effect and the application of such provision to other persons or circumstances will be interpreted so as reasonably to
effect the intent of the parties hereto. 
 17. Counterparts. This Agreement may be executed in one or more counterparts, all of
which shall be considered one and the same agreement, it being understood that each party need not sign the same counterpart. This Agreement shall become effective when each party shall have received a counterpart hereof signed by all of the other
parties. Signatures delivered electronically or by facsimile shall be deemed to be original signatures. 
 18. Survival of
Representations and Warranties. None of the representations and warranties made by the parties hereto in this Agreement shall survive the Closing. 

19. Headings and Captions. The headings and captions of the various subdivisions of this Agreement are for convenience of reference
only and shall in no way modify or affect the meaning or construction of any of the terms or provisions hereof. 
 20. Construction.
The words “include,” “includes,” and “including” will be deemed to be followed by “without limitation.” Pronouns in masculine, feminine, and neuter genders will be construed to include any other gender, and
words in the singular form will be construed to include the plural and vice versa, unless the context otherwise requires. The words “this Agreement,” 

  
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“herein,” “hereof,” “hereby,” “hereunder,” and words of similar import refer to this Agreement as a whole and not to any particular subdivision unless
expressly so limited. The word “or” shall be disjunctive but not exclusive. The parties hereto intend that each representation, warranty, and covenant contained herein will have independent significance. If any party hereto has breached
any representation, warranty, or covenant contained herein in any respect, the fact that there exists another representation, warranty or covenant relating to the same subject matter (regardless of the relative levels of specificity) which such
party has not breached will not detract from or mitigate the fact that such party is in breach of the first representation, warranty, or covenant. 

21. Mutual Drafting. This Agreement is the joint product of the parties hereto and each provision hereof has been subject to the mutual
consultation, negotiation and agreement of the parties hereto and shall not be construed for or against any party. 
 22. No Ownership
Interest. Nothing contained in this Agreement shall be deemed to vest in the Company, or any of its affiliates or Representatives, any direct or indirect ownership or incidence of ownership of or with respect to any Sponsor Shares. 

23. No Partnership, Agency or Joint Venture. This Agreement is intended to create a contractual relationship among Sponsor and the Company,
and is not intended to create, and does not create, any agency, partnership, joint venture or any like relationship between or among the parties. 

24. Termination. This Agreement shall terminate upon the earliest of (i) the termination of the BCA in accordance with its terms,
and (ii) the time this Agreement is terminated upon the mutual written agreement of BCAC, the Company and the Sponsor (the earliest such date under clause (i) and (ii) being referred to herein as the “Termination Date”);
provided, that the provisions set forth in Sections 1, 3 and 4 shall no longer be effective from and after the Closing of the Merger; provided further, that the provisions set forth in Sections
9 through 24 shall survive the Termination Date. 
 [Signature Pages Follow] 

  
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 IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed (where
applicable, by their respective officers or other authorized persons thereunto duly authorized) as of the date first written above. 
  

	
	 BCAC:
 BROOKLINE CAPITAL ACQUISTION
CORP.

	
	 /s/ Dr. Samuel P. Wertheimer

	Name: Dr. Samuel P. Wertheimer
	Title: Chief Executive Officer and Chairman
	
	SPONSOR:
	BROOKLINE CAPITAL HOLDINGS, LLC
	
	 /s/ William B. Buchanan, Jr.

	Name: William B. Buchanan, Jr.
	Title: Managing Partner
	
	 THE COMPANY:
 APEXIGEN,
INC.

	
	 /s/ Xiaodong Yang

	Name: Xiaodong Yang
	Title: Chief Executive Officer

 [Signature Page to Sponsor Support Agreement]EX-10.4

 Exhibit 10.4 

SUBSCRIPTION AGREEMENT 

This SUBSCRIPTION AGREEMENT (this “Subscription Agreement”) is entered into on March 17, 2022, by and between Brookline
Capital Acquisition Corp., a Delaware corporation (the “Company”), and the undersigned [•] (the “Subscriber”). Defined terms used but not otherwise defined herein shall have the respective meanings ascribed
thereto in the Business Combination Agreement (as defined below). 
 WHEREAS, substantially concurrently with the execution and delivery of
this Subscription Agreement, the Company is entering into that certain Business Combination Agreement, dated as of the date of this Subscription Agreement (as may be amended, supplemented or otherwise modified from time to time, the
“Business Combination Agreement”, and the transactions contemplated by the Business Combination Agreement, the “Transaction”), among the Company, Apexigen, Inc., a Delaware corporation (“Apexigen”),
and Project Barolo Merger Sub, Inc., a Delaware corporation (“Merger Sub”), providing for Merger Sub merging with and into Apexigen, with Apexigen being the surviving entity of the Transaction and being a wholly owned subsidiary of
the Company, and the Company will change its name to “Apexigen, Inc.” on the terms and subject to the conditions in the Business Combination Agreement; 

WHEREAS, in connection with the Transaction, Subscriber desires to subscribe for and purchase from the Company, immediately prior to or
concurrently with, and contingent upon, the consummation of the Transaction, (i) that number of shares of the Company’s common stock, par value $0.0001 per share (“Common Stock”), set forth on the signature page hereto
(the “Subscribed Shares”), and (ii) one-half of one private Post-IPO Warrant, as contemplated by that certain Warrant Agreement dated
January 28, 2021, which will be amended and restated immediately prior to the issuance of the Post-IPO Warrants to provide for such Post-IPO Warrants (the
“Warrant Agreement”), by and between the Company and Continental Stock Transfer & Trust Company, a New York corporation, as warrant agent (each, a “Warrant”) (each Subscribed Share and one-half of one Warrant, collectively, a “Subscribed Unit”) for a purchase price of $10.00 per Subscribed Share and one-half of one Warrant (the “Per
Unit Price” and the aggregate of such Per Unit Price for all Subscribed Units being referred to herein as the “Purchase Price”), and the Company desires to issue and sell to Subscriber the Subscribed Units in consideration
of the payment of the Purchase Price by or on behalf of Subscriber to the Company. The total number of shares of Common Stock issuable upon exercise of all of the Warrants purchased by Subscriber pursuant to this Subscription Agreement is referred
to herein as the “Warrant Shares.” Each whole Warrant entitles Subscriber to purchase one Warrant Share at an exercise price of $11.50 per share during the period commencing 30 days after the closing of the Transaction and
terminating on the five (5) year anniversary of the closing of the Transaction; and 
 WHEREAS, substantially concurrently with the
execution of this Subscription Agreement, or prior to the closing date of the Transaction (the “Closing Date”), the Company will enter into subscription agreements (the “Other Subscription Agreements” and together
with this Subscription Agreement, the “Subscription Agreements”) with certain other institutional accredited investors (the “Other Subscribers” and together with Subscriber, the “Subscribers”),
which are on substantially the same terms as the terms of this Subscription Agreement (other than the amount of the shares of Common Stock and the number of Warrants to be subscribed for and purchased by the Other Subscribers), pursuant to which
such investors shall agree to purchase on the Closing Date, inclusive of the Subscribed Units, at least $15,000,000 in aggregate purchase price of the shares of Common Stock and Warrants to be purchased by the Other Subscribers (the “Other
Subscribed Units” and together with the Subscribed Units, the “Aggregate Subscribed Units”). 
 NOW, THEREFORE, in
consideration of the foregoing and the mutual representations, warranties and covenants, and subject to the conditions, herein contained, and intending to be legally bound hereby, the parties hereto hereby agree as follows: 

 Subscription; Warrants. 

a. Subscription. Subject to the terms and conditions hereof, at the Closing (as defined below), Subscriber hereby agrees
to subscribe for and purchase, and the Company hereby agrees to issue and sell to Subscriber, upon the payment of the Purchase Price, the Subscribed Units (such subscription and issuance, the “Subscription”). The Company hereby
expressly covenants and agrees that the Purchase Price shall be used exclusively for the Transaction or after the consummation thereof by Apexigen for working capital and other corporate purposes. 

b. No Fractional Warrants; Redemption of Warrants. No fractional Warrants shall be issued by the Company other than as
part of a Subscribed Unit. If, upon the detachment of the Warrants from the Subscribed Units, or otherwise, Subscriber would be entitled to receive a fractional Warrant, the Company shall round down to the nearest whole number of Warrants to be
issued to Subscriber. The Company has the right to redeem each Warrant in accordance with the terms of the Warrant Agreement upon not less than thirty (30) days written notice at a price of $0.01 per Warrant at any time after the Warrant
becomes exercisable; so long as the last sales price of the Common Stock has been at least $18.00 per share for any twenty (20) trading days within a thirty (30) trading day period commencing after the Warrants become exercisable and
ending on the third (3rd) Business Day prior to the day on which notice is given. 
 2. Closing. 

a. The consummation of the Subscription contemplated hereby (the “Closing”) shall be contingent upon, and
occur on the Closing Date immediately prior to or concurrently with the consummation of the Transaction. 
 b. At least seven
Business Days before the anticipated Closing Date, the Company shall deliver written notice to Subscriber (the “Closing Notice”) specifying (i) the anticipated Closing Date and (ii) the wire instructions for delivery of
the Purchase Price to the Company. No later than two Business Days after receiving the Closing Notice, Subscriber shall deliver to the Company such information as is reasonably requested in the Closing Notice in order for the Company to issue the
Subscribed Shares and Warrants to Subscriber. No later than two Business Days after receiving the Closing Notice, Subscriber shall also deliver to the Company the Purchase Price, by wire transfer in immediately available funds, to the account
specified in the Closing Notice against delivery following the Closing by the Company to Subscriber of the Subscribed Shares in book entry form, free and clear of any liens or other restrictions (other than those arising under this Subscription
Agreement or state or federal securities laws), in the name of Subscriber (or its nominee in accordance with its delivery instructions) or to a custodian designated by Subscriber, as applicable, and evidence from the transfer agent of the issuance
of the Warrants, registered in the name of Subscriber (or its nominee in accordance with its delivery instructions). In the event that the consummation of the Transaction does not occur within two Business Days after the anticipated Closing Date
specified in the Closing Notice, the Company shall promptly (but in no event later than three Business Days after the anticipated Closing Date specified in the Closing Notice) return the funds so delivered by Subscriber to the Company by wire
transfer in immediately available funds to the account specified by Subscriber (and any book-entries for the Subscribed Shares shall be deemed repurchased and cancelled); provided that, unless this Subscription Agreement has been validly terminated
pursuant to Section 6 hereof, neither the failure of the Closing to 

  
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occur on the Closing Date specified in the Closing Notice nor such return of funds shall (x) terminate this Subscription Agreement, (y) be deemed to be a failure of any of the
conditions to Closing set forth in Section 2(c) hereof, or (z) otherwise relieve any party of any of its obligations hereunder, including Subscriber’s obligation to redeliver the Purchase Price and purchase the
Subscribed Shares and the Warrants at the Closing in the event the Company delivers a subsequent Closing Notice. For the purposes of this Subscription Agreement, “Business Day” means any day other than a Saturday, Sunday or a day on
which the Federal Reserve Bank of New York is closed. 
 c. The Closing shall be subject to the satisfaction or valid waiver
(to the extent a valid waiver is capable of being issued) by the Company, on the one hand, or the Subscriber, on the other, of the conditions that, on the Closing Date: 

(i) no suspension of the qualification of the Subscribed Shares or the Warrants for offering or sale or trading in any
jurisdiction, or, to the Company’s knowledge, initiation or threatening of any proceedings for any of such purposes, shall have occurred; 

(ii) all conditions precedent to the closing of the Transaction set forth in the Business Combination Agreement, including,
without limitation, the approval of the Company’s stockholders, shall have been satisfied (as determined by the parties to the Business Combination Agreement, and other than those conditions which, by their nature, are to be satisfied at the
closing of the Transaction, including to the extent that any such condition is dependent upon the consummation of the purchase and sale of the Aggregate Subscribed Units pursuant to the Subscription Agreements) or waived in writing by the party
entitled to the benefit thereof under the Business Combination Agreement, and the closing of the Transaction shall be scheduled to occur concurrently with or immediately following the Closing; and 

(iii) no governmental authority shall have enacted, issued, promulgated, enforced or entered any judgment, order, law, rule or
regulation (whether temporary, preliminary or permanent) which is then in effect and has the effect of making consummation of the transactions contemplated hereby illegal or otherwise restraining, prohibiting or enjoining consummation of the
transactions contemplated hereby (except in the case of a governmental authority located outside the United States where such judgment, order, law, rule or regulation would not be reasonably expected to have a Company Material Adverse Effect (as
defined below)); and no such governmental authority shall have instituted or threatened in writing a proceeding seeking to impose any such restraint or prohibition (except in the case of a governmental authority located outside the United States
where such restraint or prohibition would not be reasonably expected to have a Company Material Adverse Effect). 
 d. The
obligation of the Company to consummate the Closing shall be subject to the satisfaction or valid waiver by the Company of the additional conditions that, on the Closing Date: 

  
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 (i) all representations and warranties of Subscriber contained in this
Subscription Agreement are true and correct in all material respects (other than (x) representations and warranties that are qualified as to materiality or Subscriber Material Adverse Effect (as defined below), which representations and
warranties shall be true in all respects or (y) representations and warranties that speak as of a specified earlier date, which representations and warranties shall be true and correct in all material respects as of such specified date) at and
as of the Closing Date, and consummation of the Closing shall constitute a reaffirmation by Subscriber of each of the representations and warranties of Subscriber contained in this Subscription Agreement as of the Closing; and 

(ii) Subscriber shall have performed, satisfied and complied in all material respects with all covenants, agreements and
conditions required by this Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing, except where the failure of such performance, satisfaction or compliance would not or would not reasonably be expected
to prevent, materially delay, or materially impair the ability of the Company to consummate the Closing. 
 e. The obligation
of Subscriber to consummate the Closing shall be subject to the satisfaction or valid waiver by Subscriber of the additional conditions that, on the Closing Date: 

(i) all representations and warranties of the Company contained in this Subscription Agreement are true and correct in all
material respects (other than (A) representations and warranties that are qualified as to materiality or Company Material Adverse Effect (as defined below), which representations and warranties shall be true in all respects or
(B) representations and warranties that speak as of a specified earlier date, which representations and warranties shall be true and correct in all material respects as of such specified date) at and as of the Closing Date, and consummation of
the Closing shall constitute a reaffirmation by the Company of each of the representations and warranties of the Company contained in this Subscription Agreement as of the Closing; 

(ii) the Company shall have performed, satisfied and complied in all material respects with all covenants, agreements and
conditions required by this Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing, except where the failure of such performance, satisfaction or compliance would not or would not reasonably be expected
to prevent, materially delay, or materially impair the ability of the Company to consummate the Closing; and 
 (iii) there
shall have been no amendment or modification to the Business Combination Agreement that materially and adversely affects the Company or the Subscriber’s investment in the Company, other than amendments, waivers or modifications as expressly
contemplated by and included in the terms of the Business Combination Agreement as of the date of its execution. 
 f. Prior
to or at the Closing, Subscriber shall deliver to the Company a duly completed and executed Internal Revenue Service Form W-9 or appropriate Form W-8. 

  
 4 

 3. Company Representations and Warranties. For purposes of this
Section 3, the term “Company” shall refer to (i) the Company as of the date hereof, and (ii) for purposes of the representations contained in subsections (f), (j), (l), (o), and (q) of this
Section 3 and to the extent such representations and warranties are made as of the Closing Date, the combined company after giving effect to the Transaction as of the Closing Date. The Company represents and warrants
to Subscriber that as of the date hereof: 
 a. The Company (i) is duly organized, validly existing and in good standing
under the laws of the State of Delaware, (ii) has the requisite corporate power and authority to own, lease and operate its properties, to carry on its business as it is now being conducted and to enter into and perform its obligations under
this Subscription Agreement, and (iii) is duly licensed or qualified to conduct its business and, if applicable, is in good standing under the laws of each jurisdiction (other than its jurisdiction of incorporation) in which the conduct of its
business or the ownership of its properties or assets requires such license or qualification, except, with respect to the foregoing clause (iii), where the failure to be in good standing would not reasonably be expected to have a Company Material
Adverse Effect. For purposes of this Subscription Agreement, a “Company Material Adverse Effect” means any event, circumstance, change, development, effect or occurrence (collectively “Effect”) that, individually or
in the aggregate with all other Effects, (a) is or would reasonably be expected to be materially adverse to the business, financial condition or results of operations of the Company and its subsidiaries, taken as a whole; or (b) would
prevent, materially delay or materially impede the performance by the Company or its subsidiaries of their respective obligations under this Subscription Agreement, the Business Combination Agreement or the consummation of the Transaction; provided,
however, that, in the case of clause (a), none of the following shall be deemed to constitute, alone or in combination, or be taken into account in the determination of whether, there has been or will be a Company Material Adverse Effect:
(i) any change or proposed change in or change in applicable law or GAAP (including, in each case, the interpretation thereof) after the date of this Subscription Agreement; (ii) events or conditions generally affecting the industries or
geographic areas in which the Company operates; (iii) any downturn in general economic conditions, including changes in the credit, debt, securities, financial or capital markets (including changes in interest or exchange rates, prices of any
security or market index or commodity or any disruption of such markets); (iv) acts of war, sabotage, civil unrest or terrorism, or any escalation or worsening of any such acts of war, sabotage, civil unrest or terrorism, or changes in global,
national, regional, state or local political or social conditions; (v) any hurricane, tornado, flood, earthquake, mudslide, wildfire, natural disaster, epidemic, disease outbreak, pandemic (including, for the avoidance of doubt, the novel
coronavirus, SARS-CoV-2 or COVID-19 and all related strains and sequences) or other acts of God, (vi) any actions taken or
not taken by the Company as required by this Subscription Agreement, the Business Combination Agreement or any other agreement executed and delivered in connection with the Transaction and specifically contemplated by the Business Combination
Agreement or (vii) any Effect attributable to the announcement or execution, pendency, negotiation or consummation of the Transaction, except in the cases of clauses (i) through (iii), to the extent that the Company is materially and
disproportionately affected thereby as compared with other participants in the industry in which the Company operates. 
 b.
As of the Closing Date, the Subscribed Shares will be duly authorized and, when issued and delivered to Subscriber against full payment therefor in accordance with the terms of this Subscription Agreement, will be validly issued, fully paid and non-assessable and will not have been issued in violation of any preemptive rights created under the Company’s organizational documents or the laws of the State of Delaware. As of the Closing Date, the Warrant
Shares will be duly authorized and reserved for issuance and, upon exercise of the Warrants in accordance with their terms, including the payment of any exercise price therefor, will be validly issued, fully paid and
non-assessable and will not have been issued in violation of any preemptive rights created under the Company’s organizational documents or the laws of the State of Delaware. 

  
 5 

 c. The Subscribed Shares are not, and following the Closing, will not be,
subject to any Transfer Restriction. The Warrant Shares, when issued, will not be subject to any Transfer Restriction. The term “Transfer Restriction” means any condition to or restriction on the ability of the undersigned to pledge, sell,
assign or otherwise transfer the Subscribed Shares or the Warrant Shares, as applicable, under any organizational document, policy or agreement of, by or with the Company, but excluding the restrictions on transfer described in Section 4(e) of
this Subscription Agreement with respect to the status of the Subscribed Shares and the Warrant Shares as “restricted securities” pending their registration for resale under the Securities Act of 1933, as amended (the “Securities
Act”) in accordance with the terms of this Subscription Agreement. 
 d. This Subscription Agreement has been duly
authorized, executed and delivered by the Company, and assuming the due authorization, execution and delivery of the same by Subscriber, this Subscription Agreement shall constitute the valid and legally binding obligation of the Company,
enforceable against the Company in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable
remedies. 
 e. The execution and delivery of this Subscription Agreement, the issuance and sale of the Subscribed Shares and
the Warrants and the compliance by the Company with all of the provisions of this Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of the terms or
provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of the Company pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan
agreement, lease, license or other agreement or instrument to which the Company is a party or by which the Company is bound or to which any of the property or assets of the Company is subject; (ii) the organizational documents of the Company;
or (iii) any statute or any judgment, order, rule or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over the Company or any of its properties that, in the case of clauses (i) and (iii),
would reasonably be expected to have a Company Material Adverse Effect. 
 f. Assuming the accuracy of the representations
and warranties of the Subscriber, the Company is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental
authority, self-regulatory organization (including The Nasdaq Stock Market LLC (“Nasdaq”) or other person in connection with the execution, delivery and performance of this Subscription Agreement (including, without limitation, the
issuance of the Subscribed Shares and the Warrants)), other than (i) filings required by applicable state securities laws, (ii) filings with the United States Securities and Exchange Commission (the “Commission”),
including the filing of the Registration Statement pursuant to Section 5 below, (iii) filings required by the Nasdaq, or, in the event the Company becomes listed on the New York Stock Exchange
(“NYSE”), the NYSE, including with respect to obtaining approval of the Company’s stockholders, (iv) filings required to consummate the Transaction as provided under the Business Combination Agreement, (v) any filing
of notification under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, if applicable, (vi) those that will be obtained, made or given, as applicable, on or prior to the Closing, and (vii) consents, waivers, authorizations, orders,
notices or filings, the failure of which to obtain would not be reasonably likely to have a Company Material Adverse Effect. 

  
 6 

 g. Other than where the failure to timely file would not reasonably be
expected to have a Company Material Adverse Effect, as of their respective dates, all reports required to be filed by the Company with the Commission (the “SEC Reports”) complied in all material respects with the applicable
requirements in existence as of such dates of the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations of the Commission promulgated thereunder, and none of the SEC
Reports, when filed, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, as of such dates, in the light of the circumstances under
which they were made, not misleading. The financial statements of the Company included in the SEC Reports comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission with respect thereto as
in effect at the time of filing and fairly present in all material respects the financial position of the Company as of and for the dates thereof and the results of operations and cash flows for the periods then ended, subject, in the case of
unaudited statements, to normal, year-end audit adjustments. There are no material outstanding or unresolved comments in comment letters received by the Company from the staff of the Division of Corporation
Finance of the SEC with respect to any of the SEC Reports as of the date hereof. 
 h. As of the date hereof, and immediately
prior to the Closing when the Company’s certificate of incorporation shall be amended and restated to effect the Transaction, the entire authorized share capital stock of the Company consists of 25,000,000 shares of common stock (“Common
Stock”) and 1,000,000 shares of preferred stock, par value $0.0001 per share (“Preferred Shares”). As of the Closing Date (and immediately after the consummation of the Transaction), the entire authorized capital stock of the
Company will consist of 1,000,000,000 shares of Common Stock and 20,000,000 Preferred Shares. 
 i There are no stockholder
agreements, voting trusts or other agreements or understandings to which the Company is a party or by which it is bound relating to the voting securities of the Company, other than (1) as set forth in the SEC Reports and (2) as
contemplated by the Business Combination Agreement. 
 j. Except for such matters as have not had and would not be reasonably
likely to have a Company Material Adverse Effect, as of the date hereof, there is no (i) suit, action, proceeding or arbitration before a governmental authority or arbitrator pending, or, to the knowledge of the Company, threatened in writing
against the Company or (ii) judgment, decree, injunction, ruling or order of any governmental authority or arbitrator outstanding against the Company. 

k. As of the date hereof, the issued and outstanding shares of Common Stock are registered pursuant to Section 12(b) of
the Exchange Act, and are listed for trading on the Nasdaq under the symbol “BCAC” (it being understood that the trading symbol will be changed in connection with the Transaction). There is no suit, action, proceeding or investigation
pending or, to the knowledge of the Company, threatened against the Company by the Nasdaq or the Commission with respect to any intention by such entity to deregister the shares of Common Stock or prohibit or terminate the listing of the shares of
Common Stock on the Nasdaq, excluding, for the purposes of clarity, the customary ongoing review by the Nasdaq. The Company has taken no action that is designed to terminate the registration of the shares of Common Stock under the Exchange Act. 

  
 7 

 l. Assuming the accuracy of all of Subscriber’s representations and
warranties set forth in Section 4 of this Subscription Agreement, no registration under the Securities Act is required for the offer and sale of the Subscribed Shares and the Warrants by the Company to Subscriber and the
Subscribed Shares and the Warrants are not being offered in a manner involving a public offering under, or in a distribution in violation of, the Securities Act or any state securities law. 

m. Neither the Company nor any person acting on its behalf has engaged or will engage in any form of general solicitation or
general advertising (within the meaning of Regulation D) in violation of the Securities Act in connection with any offer or sale of the Subscribed Shares and the Warrants. 

n. No broker or finder is entitled to any brokerage or finder’s fee or commission from the Company solely in connection
with the sale of the Subscribed Shares and the Warrants to Subscriber. 
 o. Except for such matters as have not had and
would not be reasonably likely to have a Company Material Adverse Effect, the Company is in compliance with all state and federal laws applicable to the conduct of its business. The Company has not received any written, or to its knowledge, other
communication from a governmental entity that alleges that the Company is not in compliance with or is in default or violation of any applicable law, except where such non-compliance, default or violation
would not be reasonably likely to have, individually or in the aggregate, a Company Material Adverse Effect. 
 p. The Other
Subscription Agreements reflect the same Per Share Subscription Price and other terms with respect to the purchase of the Shares that are not materially more favorable to the Other Subscribers thereunder than the terms of this Subscription
Agreement, other than representations, warranties and terms particular to the regulatory requirements of such Other Subscriber or its affiliates or related funds. The Other Subscription Agreements have not been amended in any material respect
following the date of this Subscription Agreement. 
 q. The Company is not, and immediately after receipt of payment for the
Shares will not be, an “investment company” within the meaning of the Investment Company Act of 1940, as amended. 
 4.
Subscriber Representations and Warranties. Subscriber represents and warrants to the Company that as the date hereof: 

a. Subscriber (i) is duly organized, validly existing and in good standing under the laws of its jurisdiction of
incorporation, and (ii) has the requisite power and authority to enter into and perform its obligations under this Subscription Agreement. 

  
 8 

 b. This Subscription Agreement has been duly executed and delivered by
Subscriber, and assuming the due authorization, execution and delivery of the same by the Company, this Subscription Agreement shall constitute the valid and legally binding obligation of Subscriber, enforceable against Subscriber in accordance with
its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 

c. The execution and delivery of this Subscription Agreement, the purchase of the Subscribed Shares and the Warrants and the
compliance by Subscriber with all of the provisions of this Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of the terms or provisions of, or
constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of Subscriber pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease,
license or other agreement or instrument to which Subscriber is a party or by which Subscriber is bound or to which any of the property or assets of Subscriber is subject; (ii) the organizational documents of Subscriber; or (iii) any
statute or any judgment, order, rule or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over Subscriber or any of its properties that, in the case of clauses (i) and (iii), would reasonably be
expected to have a Subscriber Material Adverse Effect. For purposes of this Subscription Agreement, a “Subscriber Material Adverse Effect” means an event, change, development, occurrence, condition or effect with respect to
Subscriber that would reasonably be expected to have a material adverse effect on Subscriber’s ability to consummate the transactions contemplated hereby, including the purchase of the Subscribed Shares and the Warrants. 

d. Subscriber (i) is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act) or an
institutional “accredited investor” (within the meaning of Rule 501(a)(1), (2), (3), (7), (9) or (12) under the Securities Act), in either case satisfying the applicable requirements set forth on Annex A hereto and an
“institutional account” as defined in FINRA Rule 4512(c), (ii) is acquiring the Subscribed Shares and the Warrants only for its own account and not for the account of others, or if Subscriber is subscribing for the Subscribed Shares and
the Warrants as a fiduciary or agent for one or more investor accounts, each owner of such account is a qualified institutional buyer or an institutional accredited investor and Subscriber has full investment discretion with respect to each such
account, and the full power and authority to make the acknowledgements, representations and agreements herein on behalf of each owner of each such account, and (iii) is not acquiring the Subscribed Shares and the Warrants with a view to, or for
offer or sale in connection with, any distribution thereof in violation of the Securities Act (and has provided the Company with the requested information on Annex A). Subscriber is not an entity formed for the specific purpose of acquiring the
Subscribed Shares and the Warrants and is a sophisticated institutional investor, experienced in investing in private equity transactions and capable of evaluating investment risks independently, both in general and with regard to all transactions
and investment strategies involving a security or securities, including its participation in the Subscription, and has exercised independent judgment in evaluating its participation in the Subscription. 

e. Subscriber understands that the Subscribed Shares and the Warrants are being offered in a transaction not involving any
public offering within the meaning of the Securities Act and that neither the Subscribed Shares nor the Warrant Shares issuable upon exercise of the Warrants have been registered under the Securities Act. Subscriber understands that no disclosure or
offering document has been prepared in connection with 

  
 9 

 
the offer and sale of the Subscribed Shares and the Warrants. Subscriber understands that the Subscribed Shares and the Warrants may not be offered, resold, transferred, pledged (other than in
connection with ordinary course prime brokerage relationships) or otherwise disposed of by Subscriber absent an effective registration statement under the Securities Act, except (i) to the Company or a subsidiary thereof, (ii) to non-U.S. persons pursuant to offers and sales that occur outside the United States within the meaning of Regulation S under the Securities Act or (iii) pursuant to another applicable exemption from the
registration requirements of the Securities Act, and, in each of cases (ii) and (iii), in accordance with any applicable securities laws of the states and other jurisdictions of the United States, and that the Warrants and any book-entry
positions or certificates representing the Subscribed Shares or the Warrant Shares, as applicable, shall contain a legend substantially similar to the legend set forth in this Section 4(e). Subscriber understands and agrees
that the Subscribed Shares and the Warrants (and the Warrant Shares issuable upon exercise of the Warrants) will be subject to transfer restrictions under applicable securities laws and, as a result of these transfer restrictions, Subscriber may not
be able to readily offer, resell, transfer, pledge (other than in connection with ordinary course prime brokerage relationships) or otherwise dispose of the Subscribed Shares or the Warrants (or the Warrant Shares issuable upon exercise of the
Warrants) and may be required to bear the financial risk of an investment in the Subscribed Shares and the Warrants (and the Warrant Shares issuable upon exercise of the Warrant) for an indefinite period of time. Subscriber understands that it has
been advised to consult legal counsel and tax and accounting advisors prior to making any offer, resale, pledge, transfer or disposition of any of the Subscribed Shares or the Warrants (or the Warrant Shares issuable upon exercise of the Warrant).

 Each book entry for the Subscribed Shares, the Warrants and the Warrant Shares, as applicable, shall contain a notation, and each
certificate (if any) evidencing the Subscribed Shares, the Warrants or the Warrant Shares, as applicable, shall be stamped or otherwise imprinted with a legend, in substantially the following form: 

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND
MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE (NOTWITHSTANDING THE FOREGOING, THE SECURITIES REPRESENTED HEREBY MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN
OR FINANCING ARRANGEMENT SECURED BY THE SECURITIES). BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER AGREES FOR THE BENEFIT OF APEXIGEN, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE
TRANSFER THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE ISSUE DATE HEREOF OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION
THERETO AND (Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW, EXCEPT: 
 (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF,
OR 

  
 10 

 (B) PURSUANT TO A REGISTRATION STATEMENT THAT HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT
AND IS EFFECTIVE AT THE TIME OF SUCH TRANSFER, OR 
 (C) PURSUANT TO OFFERS AND SALES TO NON-U.S.
PERSONS THAT OCCUR OUTSIDE THE UNITED STATES WITHIN THE MEANING OF REGULATION S UNDER THE SECURITIES ACT, OR 
 (D) PURSUANT TO AN EXEMPTION
FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. 

PRIOR TO THE REGISTRATION OF ANY PERMITTED TRANSFER IN ACCORDANCE WITH THE ABOVE, THE COMPANY RESERVES THE RIGHT TO REQUIRE THE DELIVERY OF
SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS MADE
AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. 
 f. Subscriber
understands and agrees that Subscriber is purchasing the Subscribed Shares and the Warrants directly from the Company. Subscriber further acknowledges that there have not been, and Subscriber hereby expressly and irrevocably acknowledges and agrees
that it is not relying on, any representations, warranties, covenants or, agreements or statements made to Subscriber by or on behalf of the Company, Apexigen or the Company or Apexigen’s respective affiliates or any of the respective
subsidiaries, control persons, officers, directors, employees, partners, agents or representatives, or any other party to the Transaction or any other person or entity, expressly or by implication, (including by omission), other than those
representations, warranties, covenants, agreements and statements of the Company expressly set forth in this Subscription Agreement, and any other purported representations, warranties, covenants, agreements or statements (including by omission) are
hereby disclaimed by Subscriber. Subscriber acknowledges that certain information provided by the Company was based on projections, and such projections were prepared based on assumptions and estimates that are inherently uncertain and are subject
to a wide variety of significant business, economic and competitive risks and uncertainties that could cause actual results to differ materially from those contained in the projections. The Subscriber undertook this investment freely and after
obtaining independent legal advice. 
 g. In making its decision to purchase the Subscribed Shares and the Warrants,
Subscriber has relied solely upon independent investigation made by Subscriber and upon the representations, warranties and covenants of the Company expressly set forth herein (and no other representations and warranties). Subscriber acknowledges
and agrees that Subscriber has received such information as Subscriber deems necessary in order to make an investment decision with respect to the Subscribed Shares and the Warrants, including with respect to the Company and the Transaction
(including Apexigen and its respective subsidiaries (collectively, the “Acquired Companies”)). Without limiting the generality of the foregoing, Subscriber acknowledges that Subscriber has reviewed the SEC Reports.

  
 11 

 
Subscriber represents and agrees that Subscriber and Subscriber’s professional advisor(s), if any, have had the full opportunity to ask such questions, receive such answers and obtain such
information as Subscriber and such undersigned’s professional advisor(s), if any, have deemed necessary to make an investment decision with respect to the Subscribed Shares and the Warrants. 

h. Subscriber became aware of this offering of the Subscribed Shares and the Warrants solely by means of direct contact between
Subscriber and the Company, Apexigen or its subsidiaries and/or their respective advisors (including, without limitation, attorneys, accountants, bankers, consultants and financial advisors), agents, control persons, representatives, affiliates,
directors, officers, managers, members, and/or employees, and/or the representatives of such persons (such parties referred to collectively as “Representatives”). The Subscribed Shares and the Warrants were offered to Subscriber
solely by direct contact between Subscriber and the Company, Apexigen or its subsidiaries and/or their respective Representatives. Subscriber did not become aware of this offering of the Subscribed Shares and the Warrants, nor were the Subscribed
Shares and the Warrants offered to Subscriber, by any other means, and none of the Company, Apexigen or its subsidiaries or their respective Representatives acted as investment advisor, broker or dealer to Subscriber. Subscriber acknowledges that
the Company represents and warrants that the Subscribed Shares and the Warrants (i) were not offered by any form of general solicitation or general advertising, including methods described in Section 502(c) of Regulation D under the
Securities Act, and (ii) are not being offered in a manner involving a public offering under, or in a distribution in violation of, the Securities Act, or any state securities laws. 

i. Subscriber acknowledges that it is aware that there are substantial risks incident to the purchase and ownership of the
Subscribed Shares and the Warrants (and the Warrant Shares issuable upon exercise of the Warrants). Subscriber has such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of an investment
in the Subscribed Shares and the Warrants, and Subscriber has had an opportunity to seek, and has sought, such accounting, legal, business and tax advice as Subscriber has considered necessary to make an informed investment decision. Subscriber
acknowledges that it (i) is a sophisticated investor, experienced in investing in business and financial transactions and capable of evaluating investment risks independently, both in general and with regard to all transactions and investment
strategies involving a security or securities, and (ii) has exercised independent judgment in evaluating its purchase of the Subscribed Shares and the Warrants. Subscriber understands that the purchase and sale of the Subscribed Shares and the
Warrants hereunder meets (i) the exemptions from filing under FINRA Rule 5123(b)(1)(A) and (ii) the institutional customer exemption under FINRA Rule 2111(b) , (iii) the qualified institutional buyers exemption from filing under FINRA Rule
5123(b)(1)(C) and (iii) the accredited investors exemption from filing under FINRA Rule 5123(b)(1)(J). 
 j. Alone, or
together with any professional advisor(s), Subscriber represents and acknowledges that Subscriber has adequately analyzed and fully considered the risks of an investment in the Subscribed Shares and the Warrants and determined that the Subscribed
Shares and the Warrants are a suitable investment for Subscriber and that Subscriber is able at this time and in the foreseeable future to bear the economic risk of a total loss of Subscriber’s investment in the Company. Subscriber acknowledges
specifically that a possibility of total loss exists. 

  
 12 

 k. Subscriber understands and agrees that no federal or state agency has
passed upon or endorsed the merits of the offering of the Subscribed Shares and the Warrants or made any findings or determination as to the fairness of this investment. 

l. Subscriber is not (i) a person or entity named on the List of Specially Designated Nationals and Blocked Persons
administered by the U.S. Treasury Department’s Office of Foreign Assets Control (“OFAC”) or in any Executive Order issued by the President of the United States and administered by OFAC, or any other list of prohibited or
restricted parties promulgated by OFAC, the Department of Commerce, or the Department of State (“Consolidated Sanctions Lists”), or a person or entity prohibited or restricted by any OFAC sanctions program, or a person or entity
whose property and interests in property subject to U.S. jurisdiction are otherwise blocked under any U.S. laws, Executive Orders or regulations, (ii) a person or entity listed on the Sectoral Sanctions Identifications (“SSI”)
List maintained by OFAC or otherwise determined by OFAC to be subject to one or more of the Directives issued under Executive Order 13662 of March 20, 2014, or on any other of the Consolidated Sanctions Lists, (iii) an entity owned,
directly or indirectly, individually or in the aggregate, 50 percent or more by, acting on behalf of, or controlled by, one or more persons described in subsections (i) or (ii), (iv) organized, incorporated, established, located, resident
or born in, or a citizen, national or the government, including any political subdivision, agency or instrumentality thereof, of, Cuba, Iran, North Korea, Myanmar, Venezuela, Syria, the Crimea region of Ukraine or any other country or territory
embargoed or subject to substantial trade restrictions by the United States, (v) a person or entity named on the U.S. Department of Commerce, Bureau of Industry and Security (“BIS”) Denied Persons List, Entity List, or
Unverified List (“BIS Lists”), (vi) a Designated National as defined in the Cuban Assets Control Regulations, 31 C.F.R. Part 515, or (vii) a non-U.S. shell bank or providing banking
services indirectly to a non-U.S. shell bank. (collectively, (i) through (vii), a “Restricted Person”). Subscriber agrees to provide law enforcement agencies, if requested thereby, such
records as required by applicable law, provided that Subscriber is permitted to do so under applicable law. Subscriber represents that if it is a financial institution subject to the Bank Secrecy Act (31 U.S.C. Section 5311 et seq.), as
amended by the USA PATRIOT Act of 2001 and its implementing regulations (collectively, the “BSA/PATRIOT Act”), that Subscriber maintains policies and procedures reasonably designed to comply with applicable obligations under the
BSA/PATRIOT Act. Subscriber also represents that, to the extent required, it maintains policies and procedures reasonably designed for the screening of its investors against the OFAC and BIS sanctions programs, including for Restricted Persons, and
otherwise to ensure compliance with all applicable sanctions and embargo laws, statutes, and regulations. Subscriber further represents and warrants that, to the extent required, it maintains policies and procedures reasonably designed to ensure
that the funds held by Subscriber and used to purchase the Subscribed Shares and the Warrants were legally and were not obtained, directly or indirectly, from a Restricted Person. Subscriber is not a “foreign person,” “foreign
government,” or a “foreign entity,” in each case, as defined in Section 721 of the Defense Production Act of 1950, as amended, including, without limitation, all implementing regulations thereof (the “DPA”).
Subscriber is not controlled, in whole or in part, by a “foreign person,” as defined in the DPA. 
 m. Subscriber
does not have, as of the date hereof, and during the 30-day period immediately prior to the date hereof Subscriber has not entered into, any “put equivalent position” as such term is defined in Rule 16a-1 under the Exchange Act or short sale positions with respect to the securities of the Company. Notwithstanding the foregoing, in the case of a Subscriber that is a multi-managed investment vehicle whereby

  
 13 

 
separate portfolio managers manage separate portions of Subscriber’s assets and the portfolio managers have no direct knowledge of the investment decisions made by the portfolio managers
managing other portions of Subscriber’s assets, the representation set forth above shall only apply with respect to the portion of assets managed by the portfolio manager that made the investment decision to purchase the Subscribed Shares and
the Warrants covered by this Subscription Agreement. 
 n. If Subscriber is an employee benefit plan that is subject to Title
I of ERISA, a plan, an individual retirement account or other arrangement that is subject to Section 4975 of the Code or an employee benefit plan that is a governmental plan (as defined in Section 3(32) of ERISA), a church plan (as defined
in Section 3(33) of ERISA), a non-U.S. plan (as described in Section 4(b)(4) of ERISA) or other plan that is not subject to the foregoing but may be subject to provisions under any other federal,
state, local, non-U.S. or other laws or regulations that are similar to such provisions of ERISA or the Internal Revenue Code of 1986, as amended, or an entity whose underlying assets are considered to include
“plan assets” of any such plan, account or arrangement (each, a “Plan”) subject to the fiduciary or prohibited transaction provisions of ERISA or Section 4975 of the Code, then Subscriber represents and warrants that
neither the Company, nor any of its respective affiliates (the “Transaction Parties”) has acted as the Plan’s fiduciary, or has been relied on for advice, with respect to its decision to acquire and hold the Subscribed Shares
and the Warrants, and none of the Transaction Parties shall at any time be relied upon as the Plan’s fiduciary with respect to any decision to acquire, continue to hold or transfer the Subscribed Shares and the Warrants. 

o. At the Closing, Subscriber will have sufficient funds to pay the Purchase Price pursuant to
Section 2(b) of this Subscription Agreement. 
 p. Subscriber agrees that, notwithstanding
Section 9(i) of this Subscription Agreement, Apexigen may rely upon the representations and warranties made by Subscriber to the Company in this Subscription Agreement. 

s. No broker, finder or other financial consultant has acted on behalf of Subscriber in connection with this Subscription
Agreement or the transactions contemplated hereby in such a way as to create any liability on the Company. 
 t. Except for
the representations and warranties contained in this Section 4, Subscriber makes no express or implied representation or warranty, and Subscriber hereby disclaims any such representation or warranty with respect to the
execution and delivery of this Subscription Agreement and the consummation of the transactions contemplated herein. 
 5. Registration of
Subscribed Shares and Warrant Shares. 
 a. The Company agrees that, within forty five calendar days after the
consummation of the Transaction (the “Filing Deadline”), the Company will file with the Commission (at the Company’s sole cost and expense) a registration statement (the “Registration Statement”) registering
the resale of the Subscribed Shares and the Warrants (the “Registrable Securities”), and the Company shall use its commercially reasonable efforts to have the Registration Statement declared effective as soon as practicable after
the filing thereof, but no later than the 60th calendar day (or 120th calendar day if the Commission notifies the Company that it will
“review” the Registration Statement) 

  
 14 

 
following the Filing Deadline (such date, the “Effectiveness Date”); provided, however, that the Company’s obligations to include the Subscribed Shares and the Warrants in
the Registration Statement are contingent upon the undersigned furnishing in writing to the Company such information regarding the undersigned, the securities of the Company held by the undersigned and the intended method of disposition of the
Subscribed Shares and the Warrants as shall be reasonably requested by the Company to effect the registration of the Subscribed Shares and the Warrants, and shall execute such documents in connection with such registration as the Company may
reasonably request that are customary of a selling stockholder in similar situations. Notwithstanding the foregoing, if the Effectiveness Date falls on a day which is not a Business Day or other day that the Commission is closed for business, the
Effectiveness Date shall be extended to the next Business Day on which the Commission is open for business. Further notwithstanding the foregoing, if the Commission prevents the Company from including any or all of the securities proposed to be
registered under the Registration Statement due to limitations on the use of Rule 415 of the Securities Act for the resale of the Registrable Securities by the applicable shareholders or otherwise, such Registration Statement shall register for
resale such number of Registrable Securities which is equal to the maximum number of Registrable Securities as is permitted by the Commission. In such event, the number of Registrable Securities to be registered for each selling shareholder named in
the Registration Statement shall be reduced pro rata among all such selling shareholders. For purposes of clarification, any failure by the Company to file the Registration Statement by the Filing Deadline or to effect such Registration Statement by
the Effectiveness Date shall not otherwise relieve the Company of its obligations to file or effect the Registration Statement set forth in this Section 5. 

b. In the case of the registration, qualification, exemption or compliance effected by the Company pursuant to this
Subscription Agreement, the Company shall, upon reasonable request, respond to Subscriber as to the status of such registration, qualification, exemption and compliance. At its expense the Company shall: 

(i) except for such times as the Company is permitted hereunder to suspend the use of the prospectus forming part of a
Registration Statement, use its commercially reasonable efforts to maintain the continuous effectiveness of the Registration Statement, and to be supplemented and amended to the extent necessary to ensure that such Registration Statement is
available or, if not available, that another registration statement is available for the resale of the Subscribed Shares and the Warrants, until the earliest of (i) the date on which the Subscribed Shares and the Warrants may be resold without
volume or manner of sale limitations pursuant to Rule 144 promulgated under the Securities Act, (ii) the date on which such Subscribed Shares and the Warrants have actually been sold pursuant to Rule 144 or pursuant to the Registration
Statement, and (iii) the date which is two years after the Closing. 
 (ii) advise Subscriber, as expeditiously as
possible: 
 (1) when a Registration Statement or any amendment thereto has been filed with the Commission; 

(2) after it shall receive notice or obtain knowledge thereof, of the issuance by the Commission of any stop order suspending
the effectiveness of any Registration Statement or the initiation of any proceedings for such purpose; 

  
 15 

 (3) of the receipt by the Company of any notification with respect to the
suspension of the qualification of the Subscribed Shares and the Warrants included therein for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and 

(4) subject to the provisions in this Subscription Agreement, of the occurrence of any event that requires the making of any
changes in any Registration Statement or prospectus so that, as of such date, the statements therein are not misleading and do not omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case
of a prospectus, in the light of the circumstances under which they were made) not misleading. 
 Notwithstanding anything to
the contrary set forth herein, the Company shall not, when so advising Subscriber of such events, provide Subscriber with any material, nonpublic information regarding the Company other than to the extent that providing notice to the Company of the
occurrence of the events listed in (1) through (4) above may constitute material, nonpublic information regarding the Company; 

(iii) use its commercially reasonable efforts to obtain the withdrawal of any order suspending the effectiveness of any
Registration Statement as soon as reasonably practicable; 
 (iv) upon the occurrence of any event contemplated in
Section 5(b)(ii)(4) above, except for such times as the Company is permitted hereunder to suspend, and has suspended, the use of a prospectus forming part of a Registration Statement, the Company shall use its commercially
reasonable efforts to as soon as reasonably practicable prepare a post-effective amendment to such Registration Statement or a supplement to the related prospectus, or file any other required document so that, as thereafter delivered to purchasers
of the Subscribed Shares and the Warrants included therein, such prospectus will not include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under
which they were made, not misleading; 
 (v) cause the Subscribed Shares and the Warrants to be listed on each securities
exchange or market, if any, on which the shares of Common Stock and warrants issued by the Company have been listed; 
 (vi)
use its commercially reasonable efforts to allow Subscriber to review disclosure regarding the Subscriber in the Registration Statement; 

(vii) for as long as Subscriber holds Subscribed Shares or the Warrants, as applicable, use commercially reasonable efforts to
file all reports for so long as the condition in Rule144(c)(1) (or Rule 144(i)(2), if applicable) is required to be satisfied, and provide all customary and reasonable cooperation, necessary to enable the undersigned to resell the Registrable
Securities pursuant to Rule 144 of the Securities Act (in each case, when Rule144 of the Securities Act becomes available to Subscriber); and 

(viii) otherwise, in good faith, cooperate reasonably with, and take such customary actions as may reasonably be requested by
Subscriber, consistent with the terms of this Subscription Agreement, in connection with the registration of the Subscribed Shares and the Warrants. 

  
 16 

 c. Notwithstanding anything to the contrary in this Subscription Agreement,
the Company shall be entitled to delay or postpone the effectiveness of the Registration Statement, and from time to time to require any Subscriber not to sell under the Registration Statement or to suspend the effectiveness thereof, (x) if (i)
it determines that in order for the Registration Statement not to contain a material misstatement or omission, an amendment or supplement thereto would be needed or (ii) the negotiation or consummation of a transaction by the Company or its
subsidiaries is pending or an event has occurred, which negotiation, consummation or event, the Company’s board of directors reasonably believes, upon the advice of legal counsel, would require additional disclosure by the Company in the
Registration Statement of material information that the Company has a bona fide business purpose for keeping confidential and the non-disclosure of which in the Registration Statement would be expected, in the
reasonable determination of the Company’s board of directors, upon the advice of legal counsel, to cause the Registration Statement to fail to comply with applicable disclosure requirements and (y) as may be necessary in connection with
the preparation and filing of a post-effective amendment to the Registration Statement following the filing of the Company’s (including the combined company after giving effect to the Transaction) Annual Report on Form 10-K for its first completed fiscal year following the Closing (each such circumstance, a “Suspension Event”); provided, however, that the Company may not delay or suspend the Registration Statement
on more than two occasions or for more than sixty consecutive calendar days, or more than a total of ninety calendar days, in each case during any twelve-month period. Upon receipt of any written notice from the Company of the happening of any
Suspension Event (which notice shall not contain material non-public information) during the period that the Registration Statement is effective or if as a result of a Suspension Event the Registration
Statement or related prospectus contains any untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made
(in the case of the prospectus) not misleading, Subscriber agrees that (i) it will immediately discontinue offers and sales of the Subscribed Shares and the Warrants under the Registration Statement (excluding, for the avoidance of doubt, sales
conducted pursuant to Rule 144) until Subscriber receives copies of a supplemental or amended prospectus (which the Company agrees to promptly prepare) that corrects the misstatement(s) or omission(s) referred to above and receives notice that any
post-effective amendment has become effective or unless otherwise notified by the Company that it may resume such offers and sales, and (ii) it will maintain the confidentiality of any information included in such written notice delivered by
the Company unless otherwise required by law or subpoena. If so directed by the Company, Subscriber will deliver to the Company or, in Subscriber’s sole discretion destroy, all copies of the prospectus covering the Subscribed Shares and the
Warrants in Subscriber’s possession; provided, however, that this obligation to deliver or destroy all copies of the prospectus covering the Subscribed Shares and the Warrants shall not apply (i) to the extent Subscriber is required to
retain a copy of such prospectus (a) in order to comply with applicable legal, regulatory, self-regulatory or professional requirements or (b) in accordance with a bona fide pre-existing document
retention policy or (ii) to copies stored electronically on archival servers as a result of automatic data back-up. 

d. If the total number of shares of Common Stock that Subscriber and any other person(s) intend to include in an underwritten
offering exceeds the number of shares of Common Stock that can be sold in an underwritten offering without being likely to have an adverse effect on the price, timing or distribution of shares of the Common Stock offered or the market for the shares
of Common Stock as determined by the managing underwriter 

  
 17 

 
of such offering, then the shares of Common Stock to be included in such offering shall include the number of shares of Common Stock that the managing underwriter of the offering advises the
Company can be sold without having such adverse effect, with such number to be allocated (i) first, to the Company or other party or parties requesting or initiating such registration or to any other holder of securities of the Company having
rights of registration pursuant to an existing registration rights agreement and (ii) second, Subscribers, allocated among the Subscribers on the basis of the number of shares of Common Stock proposed to be sold by each applicable member of the
Subscribers in such underwritten offering (based, for each such participant, described in this clause (ii), on the percentage derived by dividing (x) the number of shares of Common Stock proposed to be sold by such participant in such
underwritten offering by (y) the aggregate number of shares of Common Stock proposed to be sold by all such participants) or in such manner as they may agree, and (iii) third, to other holders of shares of Common Stock with registration
rights entitling them to participate in such underwritten offering. 
 e. The Company shall, notwithstanding any termination
of this Subscription Agreement, indemnify, defend and hold harmless Subscriber (to the extent a seller under the Registration Statement), and its officers, directors and agents, and each person who controls Subscriber (within the meaning of
Section 15 of the Securities Act or Section 20 of the Exchange Act) to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable
attorneys’ fees) and expenses (collectively, “Losses”), as incurred, that arise out of or are based upon (i) any untrue or alleged untrue statement of a material fact contained in the Registration Statement, any prospectus
included in the Registration Statement or any form of prospectus or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission to state a material fact required to be
stated therein or necessary to make the statements therein (in the case of any prospectus or form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading, or (ii) any violation or alleged
violation by the Company of the Securities Act, Exchange Act or any state securities law or any rule or regulation thereunder, in connection with the performance of its obligations under this Section 5, except, in each
case, to the extent, but only to the extent, that such untrue statements, alleged untrue statements, omissions or alleged omissions are based upon information regarding Subscriber furnished in writing to the Company by Subscriber expressly for use
therein or such Subscriber has omitted a material fact from such information or otherwise violated the Securities Act, Exchange Act or any state securities law or any rule or regulation thereunder; provided, however, that the indemnification
contained in this Section 5 shall not apply to amounts paid in settlement of any Losses if such settlement is effected by Subscriber without the consent of the Company (which consent shall not be unreasonably withheld,
conditioned or delayed), nor shall the Company be liable for any Losses to the extent they arise out of or are based upon a violation which occurs (A) in reliance upon and in conformity with written information furnished by a Subscriber,
(B) in connection with any failure of Subscriber to deliver or cause to be delivered a prospectus made available to Subscriber by the Company in a timely manner, (C) as a result of offers or sales effected by or on behalf of Subscriber by
means of a free writing prospectus (as defined in Rule 405) that was not authorized by the Company, or (D) in connection with any offers or sales effected by or on behalf of a Subscriber in violation of Section 5(b) of
this Subscription Agreement. The Company shall notify such Subscriber promptly of the institution, threat or assertion of any proceeding arising from or in connection with the transactions contemplated by this Section 5 of
which the Company is aware. The indemnity set forth in this Section 5(d) shall remain in full force and effect regardless of any investigation made by or on behalf of an indemnified party and shall survive the transfer of
the Subscribed Shares and/or the Warrants, as applicable, by Subscriber. 

  
 18 

 f. Subscriber, severally and not jointly with the Other Subscribers, shall
indemnify and hold harmless the Company, its directors, officers, agents, trustees, partners, members, managers, stockholders, affiliates, investment advisors and employees, and each person who controls the Company (within the meaning of
Section 15 of the Securities Act and Section 20 of the Exchange Act), to the fullest extent permitted by applicable law, from and against all Losses, as incurred, arising out of or based upon any untrue or alleged untrue statement of a
material fact contained in the Registration Statement, any prospectus included in the Registration Statement, or any form of prospectus, or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any
omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any prospectus, or any form of prospectus or supplement thereto, in light of the circumstances under which they
were made) not misleading to the extent, but only to the extent, that such untrue statements or omissions are based upon information regarding Subscriber furnished in writing to the Company by Subscriber expressly for use therein; provided, however,
that the indemnification contained in this Section 5(f) shall not apply to amounts paid in settlement of any Losses if such settlement is effected without the consent of Subscriber (which consent shall not be unreasonably
withheld, conditioned or delayed) nor shall Subscriber be liable for any Losses to the extent they arise out of or are based upon a violation which occurs in reliance upon and in conformity with written information furnished by the Company. In no
event shall the liability of any Subscriber be greater in amount than the dollar amount of the net proceeds received by Subscriber upon the sale of the Subscribed Shares and/or the Warrants, as applicable, giving rise to such indemnification
obligation. Subscriber shall notify the Company promptly of the institution, threat or assertion of any proceeding arising from or in connection with the transactions contemplated by this Section 5(f) of which such
Subscriber is aware of which Subscriber shall seek indemnification under this Subscription Agreement; provided that the failure by Subscriber to give such notice shall not relieve the Company of its indemnification obligations hereunder, except to
the extent that the failure to give such notice is materially prejudicial to the company’s ability to defend such claim or litigation. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of
an indemnified party and shall survive the transfer of the Subscribed Shares and/or the Warrants, as applicable, by Subscriber. 

g. Any person or entity entitled to indemnification herein shall (i) give prompt written notice to the indemnifying party
of any claim with respect to which it seeks indemnification (provided that the failure to give prompt notice shall not impair any person’s or entity’s right to indemnification hereunder to the extent such failure has not prejudiced the
indemnifying party) and (ii) unless in such indemnified party’s reasonable judgment a conflict of interest between such indemnified and indemnifying parties may exist with respect to such claim, permit such indemnifying party to assume the
defense of such claim with counsel reasonably satisfactory to the indemnified party. If such defense is assumed, the indemnifying party shall not be subject to any liability for any settlement made by the indemnified party without its consent (but
such consent shall not be unreasonably withheld, conditioned or delayed). An indemnifying party who is not entitled to, or elects not to, assume the defense of a claim shall not be obligated to pay the fees and expenses of more than one counsel for
all parties indemnified by such indemnifying party 

  
 19 

 
with respect to such claims, unless in the reasonable judgment of any indemnified party a conflict of interest may exist between such indemnified party and any other of such indemnified parties
with respect to such claim. No indemnifying party shall, without the consent of the indemnified party, consent to the entry of any judgment or enter into any settlement which cannot be settled in all respects by the payment of money (and such money
is so paid by the indemnifying party pursuant to the terms of such settlement), which settlement shall not include a statement or admission of fault and culpability on the party of such indemnified party, and which settlement shall include as an
unconditional term thereof the giving by the claimant or plaintiff to such indemnified party of a release from all liability in respect to such claim or litigation. 

h. If the indemnification provided under this Section 5 from the indemnifying party is unavailable or
insufficient to hold harmless an indemnified party in respect of any Losses referred to herein, then the indemnifying party, in lieu of indemnifying the indemnified party, shall contribute to the amount paid or payable by the indemnified party as a
result of such Losses in such proportion as is appropriate to reflect the relative fault of the indemnifying party and the indemnified party, as well as any other relevant equitable considerations; provided, however, that the liability of the
Subscriber shall be limited to the net proceeds received by Subscriber from the sale of Subscribed Shares and/or the Warrants, applicable, giving rise to such indemnification obligation. The relative fault of the indemnifying party and indemnified
party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact, was made by (or not made by,
in the case of an omission), or relates to information supplied by (or not supplied by, in the case of an omission) such indemnifying party or indemnified party, and the indemnifying party’s and indemnified party’s relative intent,
knowledge, access to information and opportunity to correct or prevent such action. The amount paid or payable by a party as a result of the Losses shall be deemed to include, subject to the limitations set forth in this Section 5, any legal or
other fees, charges or expenses reasonably incurred by such party in connection with any investigation or proceeding. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled
to contribution pursuant to this Section 5(h) from any person or entity who was not guilty of such fraudulent misrepresentation. 

i. The Subscriber may deliver written notice (an “Opt-Out Notice”) to
the Company requesting that the Subscriber not receive notices from the Company otherwise required by this Section 5; provided, however, that the Subscriber may later revoke any such
Opt-Out Notice in writing. Following receipt of an Opt-Out Notice from the Subscriber (unless subsequently revoked), (i) the Company shall not deliver any such notices
to the Subscriber and the Subscriber shall no longer be entitled to the rights associated with any such notice and (ii) each time prior to the Subscriber’s intended use of an effective Registration Statement, the Subscriber will notify the
Company in writing at least two Business Days in advance of such intended use, and if a notice of a Suspension Event was previously delivered (or would have been delivered but for the provisions of this Section 5(i)) and
the related suspension period remains in effect, the Company will so notify the Subscriber, within one Business Day of the Subscriber’s notification to the Company, by delivering to the Subscriber a copy of such previous notice of Suspension
Event, and thereafter will provide the Subscriber with the related notice of the conclusion of such Suspension Event immediately upon its availability (which notices shall not contain any material, nonpublic information or subject the Subscriber to
any duty of confidentiality). 

  
 20 

 j. For purposes of this Section 5, (i)
“Subscriber” shall include any person to whom the rights under this Section 5 shall have been duly assigned and (ii) “Subscribed Shares” shall mean, as of any date of determination, the
Subscribed Shares acquired by the Subscriber pursuant to this Subscription Agreement and any other equity security issued or issuable with respect to such Subscribed Shares by way of share split, dividend, distribution, recapitalization, merger,
exchange, replacement or similar event. 
 6. Termination. This Subscription Agreement shall terminate and be void and of no further
force and effect, and all rights and obligations of the parties hereunder shall terminate without any further liability on the part of any party in respect thereof, upon the earlier to occur of (a) such date and time as the Business Combination
Agreement is terminated in accordance with its terms, (b) upon the mutual written agreement of the Company and the Subscriber to terminate this Subscription Agreement, or (c) September 30, 2022, if Closing has not occurred by such
date (the “Outside Date”); provided, that nothing herein will relieve any party from liability for any willful breach hereof (including, for the avoidance of doubt, a Subscriber’s willful breach of
Section 2(c) of this Subscription Agreement with respect to its representations, warranties and covenants as of the date of the Closing) prior to the time of termination, and each party will be entitled to any remedies at
law or in equity to recover losses, liabilities or damages arising from such breach. The Company shall notify Subscriber of the termination of the Business Combination Agreement promptly after the termination thereof. For the avoidance of doubt, if
any termination hereof occurs after the delivery by the Subscriber of the Purchase Price for the Subscribed Shares and the Warrants, the Company shall promptly (but not later than one Business Day thereafter) return the Purchase Price to the
Subscriber by wire transfer of immediately available funds to the account specified by Subscriber without any deduction for or on account of any tax, withholding, charges, or set-off. 

7. No Short Sales. Subscriber hereby agrees that neither it, nor any person or entity acting on its behalf, will engage in any Short
Sales with respect to securities of the Company prior to the closing of the Transaction. For purposes of this Section 7, “Short Sales” shall include, without limitation, all “short sales” as
defined in Rule 200 promulgated under Regulation SHO under the Exchange Act, and all types of direct and indirect stock pledges (other than pledges in the ordinary course of business as part of prime brokerage arrangements), forward sale contracts,
options, puts, calls, swaps and similar arrangements (including on a total return basis). 
 8. Trust Account Waiver. Subscriber
hereby acknowledges that the Company has established a trust account (the “Trust Account”) containing the proceeds of its initial public offering (the “IPO”) and from certain private placements occurring
simultaneously with the IPO (including interest accrued from time to time thereon) for the benefit of the Company’s public stockholders and certain other parties (including the underwriters of the IPO). For and in consideration of the Company
entering into this Subscription Agreement, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Subscriber hereby (i) agrees that it does not now and shall not at any time hereafter have
any right, title, interest or claim of any kind in or to any assets held in the Trust Account, and shall not make any claim against the Trust Account, in each case, to the extent such claim arises as a result of, in connection with or relating in
any way to this Subscription Agreement or any other matter, and regardless of whether such claim arises based on contract, tort, equity or any other theory of legal liability (any and all such claims are collectively referred to hereafter as the
“Released Claims”), (ii) irrevocably waives any Released Claims that it may have against the Trust Account now or in the future as a result of, or arising out of, any negotiations, contracts or agreements with the Company, and
(iii) will not seek recourse against the Trust Account for any reason whatsoever; provided however, that nothing in this Section 7 shall be deemed to limit any Subscriber’s right to distributions or redemptions
from the Trust Account in accordance with the Company’s amended and restated certificate of incorporation in respect of any redemptions by Subscriber of its shares of public Common Stock of the Company currently outstanding on the date hereof
and acquired by any means other than pursuant to this Subscription Agreement. 

  
 21 

 
Subscriber agrees not to seek recourse or make or bring any action, suit, claim or other proceeding against the Trust Account as a result of, or arising out of, this Subscription Agreement, the
transactions contemplated hereby or the Subscribed Shares and the Warrants regardless of whether such claim arises based on contract, tort, equity or any other theory of legal liability. The Subscriber acknowledges and agrees that it shall not have
any redemption rights with respect to the Subscribed Shares or the Warrants, as applicable, (or the Warrant Shares issuable upon exercise of the Warrants) pursuant to the Company’s organizational documents in connection with the Transaction or
any other business combination, any subsequent liquidation of the Trust Account, the Company or otherwise. In the event Subscriber has any claim against the Company as a result of, or arising out of, this Subscription Agreement, the transactions
contemplated hereby or the Subscribed Shares or the Warrants, as applicable, (or the Warrant Shares issuable upon exercise of the Warrants), it shall pursue such claim solely against the Company and its assets outside the Trust Account and not
against the Trust Account or any monies or other assets in the Trust Account. 
  

	 	9.	 Miscellaneous. 

a. All notices, requests, demands, claims, and other communications hereunder shall be in writing. Any notice, request, demand,
claim, or other communication hereunder shall be deemed duly given (i) when delivered personally to the recipient, (ii) when sent by electronic mail, on the date of transmission to such recipient; provided, that such notice, request,
demand, claim or other communication is also sent to the recipient pursuant to clauses (i), (iii) or (iv) of this Section 9(a), (iii) one Business Day after being sent to the recipient by reputable overnight courier
service (charges prepaid), or (iv) four Business Days after being mailed to the recipient by certified or registered mail, return receipt requested and postage prepaid, and, in each case, addressed to the intended recipient at its address
specified on the signature page hereof or to such electronic mail address or address as subsequently modified by written notice given in accordance with this Section 9(a). 

b. Subscriber acknowledges that the Company and Apexigen will rely on the acknowledgments, understandings, agreements,
representations and warranties made by Subscriber contained in this Subscription Agreement. Prior to the Closing, Subscriber agrees to promptly notify the Company and Apexigen if it becomes aware that any of the acknowledgments, understandings,
agreements, representations and warranties of Subscriber set forth herein are no longer accurate in all material respects. The Company acknowledges that Subscriber and others will rely on the acknowledgments, understandings, agreements,
representations and warranties contained in this Subscription Agreement. 
 c. Each of the Company, Apexigen and Subscriber
is irrevocably authorized to produce this Subscription Agreement or a copy hereof to any interested party as requested or required by law, rule or regulation in any administrative or legal proceeding or official inquiry with respect to the matters
covered hereby. 
 d. Regardless of whether the Closing occurs, Subscriber shall pay all of its own expenses in connection
with this Subscription Agreement and the transactions contemplated herein. 

  
 22 

 e. Neither this Subscription Agreement nor any rights that may accrue to
Subscriber hereunder (other than the Subscribed Shares and the Warrants acquired hereunder, if any, and the Warrant Shares issued upon exercise of the Warrants, if applicable) may be transferred or assigned. Neither this Subscription Agreement nor
any rights that may accrue to the Company hereunder may be transferred or assigned (provided, that, for the avoidance of doubt, the Company may transfer the Subscription Agreement and its rights hereunder solely in connection with the consummation
of the Transaction and exclusively to another entity under the control of, or under common control with, the Company). Notwithstanding the foregoing, Subscriber may assign its rights and obligations under this Subscription Agreement to one or more
of its affiliates (including other investment funds or accounts managed or advised by the investment manager who acts on behalf of the Subscriber) or, with the Company’s prior written consent, to another person, provided that no such assignment
shall relieve Subscriber of its obligations hereunder if any such assignee fails to perform such obligations, unless the Company has given its prior written consent to such relief, and such assignee agrees in writing to be bound by the terms hereof.
The parties hereto acknowledge and agree that (i) Apexigen is a third party beneficiary hereof and no consent, waiver, modification or amendment hereunder or hereof may be given or agreed to by the Company without Apexigen’s prior written
consent, (ii) this Subscription Agreement is being entered into in order to induce each of the Company and Apexigen to execute and deliver the Business Combination Agreement and without the representations, warranties, covenants and agreements
of the Company and Subscriber hereunder, each of the Company and Apexigen would not enter into the Business Combination Agreement, (iii) each representation, warranty, covenant and agreement of the Company and Subscriber hereunder is being made
also for the benefit of Apexigen, and (iv) Apexigen may directly enforce (including by an action for specific performance, injunctive relief or other equitable relief) each of the covenants and agreements of each of the Company and Subscriber
under this Subscription Agreement as amended, modified, supplemented or waived in accordance with Section 9(h). 
 f.
All the agreements, representations and warranties made by each party hereto in this Subscription Agreement shall survive the Closing. 

g. The Company may request from Subscriber such additional information as the Company may reasonably determine necessary to
evaluate the eligibility of Subscriber to acquire the Subscribed Shares and the Warrants, to register the resale of the Subscribed Shares and the Warrant Shares or otherwise consummate or evidence the transaction contemplated by this Subscription
Agreement, and Subscriber shall provide such information as may be reasonably requested, to the extent readily available and to the extent consistent with its internal policies and procedures provided that Company agrees to keep any such information
provided by Subscriber confidential other than as necessary to include in any registration statement the Company is required to file hereunder or in connection herewith. Subscriber acknowledges and agrees that if it does not provide the Company with
such requested information, the Company may not be able to register the Subscribed Shares and the Warrant Shares for resale pursuant to Section 5 hereof. Subscriber hereby agrees that the Subscription Agreement, as well as
the nature of Subscriber’s obligations hereunder, may be disclosed in any public announcement or disclosure required by the Commission and in any registration statement, proxy statement, consent solicitation statement or any other Commission
filing to be filed by the Company in connection with the issuance of the Subscribed Shares and the Warrants contemplated by this Subscription Agreement and/or the Transaction, in each case without the Subscriber’s prior written consent. 

  
 23 

 h. This Subscription Agreement may not be amended, modified, waived or
terminated except by an instrument in writing, signed by each of the parties hereto, and Apexigen; provided, that this Subscription Agreement may be amended, modified, waived or terminated with the written consent of the Company, Apexigen and the
holders then committed to purchase a majority of the Aggregate Subscribed Units (based on the number of Subscribed Shares and the number of Warrant Shares underlying the Warrants) to be purchased at the Closing, including each holder (which includes
Subscriber, its affiliates and accounts and funds controlled or managed by Subscriber or its affiliates) then committed to purchase at least $3,000,000 of the Aggregate Subscribed Units (or, if after the Closing, the Company and the holders then
holding a majority of the then outstanding Aggregate Subscribed Units (based on the number of Subscribed Shares and the number of Warrant Shares underlying the Warrants), including each holder (which includes Subscriber, its affiliates and accounts
and funds controlled or managed by Subscriber or its affiliates) of at least $3,000,000 of then outstanding Aggregate Subscribed Units, based on the original purchase price) pursuant to this Subscription Agreement and the Other Subscription
Agreements (collectively, the “Required Subscriber”). Upon the effectuation of such waiver, modification, amendment or termination with the consent of the Required Subscriber in conformance with this
Section 9(h), such amendment, modification, waiver or termination shall be binding on the Subscriber and effective as to all of this Subscription Agreement. The Company shall promptly give written notice thereof to
Subscriber if Subscriber has not previously consented to such amendment, modification, waiver or termination in writing; provided that the failure to give such notice shall not affect the validity of such amendment, modification, waiver or
termination. Notwithstanding anything to the contrary herein, (i) any amendment, modification or waiver that has a disproportionate materially adverse effect on Subscriber (considered apart from any disproportionate effect owing to the
aggregate amount of the Subscribed Shares and the Warrants held by such Subscriber), relative to any of the Other Subscribers shall require the consent of Subscriber, (ii) any amendment to Section 5 or
Section 6 of this Subscription Agreement shall require the consent of Subscriber, (iii) any amendment, modification or other change that alters the Per Share Purchase Price, the Purchase Price, the number of Subscribed
Shares or the number of Warrant Shares issuable upon exercise of the Warrants shall require the consent of Subscriber, and (iv) upon the execution of the Business Combination Agreement and related public announcement of the Transaction, the
Company may, without Subscriber’s consent, enter into subscription agreements with any other person. 
 i. This
Subscription Agreement constitutes the entire agreement, and supersedes all other prior agreements, understandings, representations and warranties, both written and oral, among the parties hereto, with respect to the subject matter hereof, except
that any confidentiality agreement with respect to the undersigned or its affiliates shall remain in full force and effect following the amendment, modification, waiver or termination of this Subscription Agreement. 

j. Except as otherwise provided herein, this Subscription Agreement shall be binding upon, and inure to the benefit of the
parties hereto and their heirs, executors, administrators, successors, legal representatives, and permitted assigns, and the agreements, representations, warranties, covenants and acknowledgments contained herein shall be deemed to be made by, and
be binding upon, such heirs, executors, administrators, successors, legal representatives and permitted assigns. The parties hereto acknowledge and agree that Apexigen (an express third-party beneficiary) shall be entitled to specifically enforce
Subscriber’s obligation to fund the Purchase Price and the provisions of this Subscription Agreement on the terms and subject to the conditions set forth in this Subscription Agreement. Each of the parties hereto shall be entitled to seek and
obtain 

  
 24 

 
equitable relief, without proof of actual damages, including an injunction or injunctions or order for specific performance to prevent breaches of this Subscription Agreement and to enforce
specifically the terms and provisions of this Subscription Agreement to cause Subscriber to fund the Purchase Price and cause the Closing to occur if the conditions in Section 2 of this Subscription Agreement have been
satisfied or, to the extent permitted by applicable law, waived by the applicable party entitled to waive any such condition. Each party hereto further agrees that none of the parties hereto shall be required to obtain, furnish or post any bond or
similar instrument in connection with or as a condition to obtaining any remedy referred to in this Section 9(j), and each party hereto irrevocably waives any right it may have to require the obtaining, furnishing or
posting of any such bond or similar instrument. 
 k. If any provision of this Subscription Agreement shall be invalid,
illegal or unenforceable, the validity, legality or enforceability of the remaining provisions of this Subscription Agreement shall not in any way be affected or impaired thereby and shall continue in full force and effect. 

l. This Subscription Agreement may be executed and delivered in one or more counterparts (including by facsimile or electronic
mail or in .pdf or any other form of electronic delivery (including any electronic signature complying with U.S. federal ESIGN Act of 2000)) and by different parties in separate counterparts, with the same effect as if all parties hereto had signed
the same document. All counterparts so executed and delivered shall be construed together and shall constitute one and the same agreement. 

m. The parties hereto agree that irreparable damage would occur in the event that any of the provisions of this Subscription
Agreement were not performed in accordance with their specific terms or were otherwise breached. It is accordingly agreed that the parties hereto and Apexigen shall be entitled to seek an injunction or injunctions to prevent breaches or threatened
breaches of this Subscription Agreement and to enforce specifically the terms and provisions of this Subscription Agreement, this being in addition to any other remedy to which such party is entitled to seek at law, in equity, in contract, in tort
or otherwise. The parties hereto further agree not to assert that a remedy of specific enforcement pursuant to this Section 9(m) is unenforceable, invalid, contrary to applicable law or inequitable for any reason and to
waive any defenses in any action for specific performance, including the defense that a remedy at law would be adequate. In connection with any action for which Apexigen is entitled to an award of money damages, each of the Company and Subscriber
agrees that such damages, to the extent payable by such party, shall include, without limitation, damages related to the cash consideration that is or was to be paid to Apexigen or its equity holders under the Business Combination Agreement and/or
this Subscription Agreement, and such damages are not limited to an award of out-of-pocket fees and expenses related to the Business Combination Agreement and this
Subscription Agreement. The parties acknowledge and agree that this Section 9(m) is an integral part of the transactions contemplated hereby and without that right, the parties hereto would not have entered into this
Subscription Agreement. 
 n. This Subscription Agreement shall be governed by, and construed in accordance with, the laws of
the State of New York, without regard to the principles of conflicts of laws that would otherwise require the application of the law of any other state. 

  
 25 

 o. EACH PARTY HEREBY WAIVES ITS RESPECTIVE RIGHTS TO A TRIAL BY JURY OF
ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OR RELATED TO THIS SUBSCRIPTION AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY IN ANY ACTION, PROCEEDING OR OTHER LITIGATION OF ANY TYPE BROUGHT BY ANY PARTY AGAINST ANY OTHER PARTY OR ANY
AFFILIATE OF ANY OTHER SUCH PARTY, WHETHER WITH RESPECT TO CONTRACT CLAIMS, TORT CLAIMS OR OTHERWISE. THE PARTIES AGREE THAT ANY SUCH CLAIM OR CAUSE OF ACTION SHALL BE TRIED BY A COURT TRIAL WITHOUT A JURY. WITHOUT LIMITING THE FOREGOING, THE
PARTIES FURTHER AGREE THAT THEIR RESPECTIVE RIGHT TO A TRIAL BY JURY IS WAIVED BY OPERATION OF THIS SECTION AS TO ANY ACTION, COUNTERCLAIM OR OTHER PROCEEDING WHICH SEEKS, IN WHOLE OR IN PART, TO CHALLENGE THE VALIDITY OR ENFORCEABILITY OF THIS
SUBSCRIPTION AGREEMENT OR ANY PROVISION HEREOF. THIS WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS SUBSCRIPTION AGREEMENT. 

p. The parties agree that all disputes, legal actions, suits and proceedings arising out of or relating to this Subscription
Agreement must be brought exclusively in the state courts of New York or in the federal courts located in the state and county of New York (collectively the “Designated Courts”). Each party hereby consents and submits to the
exclusive jurisdiction of the Designated Courts. No legal action, suit or proceeding with respect to this subscription agreement may be brought in any other forum. Notwithstanding the foregoing, a final judgement in any such action may be enforced
in other jurisdictions by suit on the judgment or in any other manner provided by law. Each party hereby irrevocably waives all claims of immunity from jurisdiction and any objection which such party may now or hereafter have to the laying of venue
of any suit, action or proceeding in any Designated Court, including any right to object on the basis that any dispute, action, suit or proceeding brought in the Designated Courts has been brought in an improper or inconvenient forum or venue. Each
of the parties also agrees that delivery of any process, summons, notice or document to a party hereof in compliance with Section 9(a) of this Subscription Agreement shall be effective service of process for any action,
suit or proceeding in a Designated Court with respect to any matters to which the parties have submitted to jurisdiction as set forth above. 

q. This Subscription Agreement may only be enforced against, and any claim, action, suit or other legal proceeding based upon,
arising out of, or related to this Subscription Agreement, or the negotiation, execution or performance of this Subscription Agreement, may only be brought against the entities that are expressly named as parties hereto and then only with respect to
the specific obligations set forth herein with respect to such party. No past, present or future director, officer, employee, incorporator, manager, member, partner, stockholder, affiliate, agent, attorney or other representative of any party hereto
or of any affiliate of any party hereto, or any of their successors or permitted assigns, shall have any liability for any obligations or liabilities of any party hereto under this Subscription Agreement or for any claim, action, suit or other legal
proceeding based on, in respect of or by reason of the transactions contemplated hereby. 

  
 26 

 r. The Company shall, by 9:00 a.m., Eastern Time, on the first Business Day
immediately following the date of this Subscription Agreement, issue one or more press releases or file with the Commission a Current Report on Form 8-K (collectively, the “Disclosure
Document”) disclosing, to the extent not previously publicly disclosed, all material terms of the transactions contemplated hereby (and by the Other Subscription Agreements), the Transaction and any other material, nonpublic information
that the Company has provided to Subscriber at any time prior to the filing of the Disclosure Document. From and after the issuance of the Disclosure Document, to the actual knowledge of the Company, Subscriber shall not be in possession of any
material, non-public information received from the Company or any of its officers, directors or employees. Notwithstanding the foregoing, or anything contained to the contrary in
Section 9(c), the Company shall not publicly disclose the name of Subscriber or any affiliate or investment advisor of Subscriber, or include the name of Subscriber or any affiliate or investment advisor of Subscriber in
any press release or in any filing with the Commission or any regulatory agency or trading market, without the prior written consent (including by e-mail) of Subscriber, except as required by the federal
securities laws, rules or regulations and to the extent such disclosure is required by other laws, rules or regulations, at the request of the staff of the Commission or regulatory agency or under Nasdaq regulations, in which case the Company shall
provide Subscriber with reasonable prior written notice (including by e-mail) of such permitted disclosure, and shall reasonably consult with Subscriber regarding such disclosure. Subject to the limitations of
the following sentence, Subscriber hereby consents to the publication and disclosure in any Form 8-K filed by the Company with the Commission, in any filing with the Commission made in connection with the
Business Combination Agreement and the Transaction, including any proxy statement, prospectus or registration statement related thereto or any other filing with the Commission pursuant to applicable securities laws, of Subscriber’s name and
identity and the nature of Subscriber’s commitments, arrangements and understandings under and relating to this Subscription Agreement and, if deemed required or appropriate by the Company, a copy of this Subscription Agreement. Any such
disclosure under the foregoing two sentences shall be made only after the Company as soon as practicable notifies the Subscriber of such requirement to disclose (except where prohibited by applicable law, legal process or regulatory request) so that
the Subscriber (or its applicable affiliate) may seek a protective order or other appropriate remedy prior to such disclosure. The Company shall provide a draft of any proposed disclosures under this Section 9(r) to
Subscriber reasonably in advance of the release of such disclosures, but in no event less than one Business Day prior to release, and shall consider in good faith any revisions to such disclosure proposed by Subscriber. Notwithstanding the foregoing
or anything contained to the contrary in Section 9(c), the Company may make disclosures to an auditor or governmental or regulatory authority pursuant to any routine investigation, inspection, examination or inquiry without
providing the Subscriber with any notification thereof, unless the Subscriber is the subject of any such investigation, inspection, examination or inquiry (in which case the preceding sentence shall govern). 

t. The obligations of Subscriber under this Subscription Agreement are several and not joint with the obligations of any of the
Other Subscribers or any other investor under the Other Subscription Agreements, and Subscriber shall not be responsible in any way for the performance of the obligations of any Other Subscriber under this Subscription Agreement or any other
investor under the Other Subscription Agreements. The decision of Subscriber to purchase Subscribed Shares and the Warrants pursuant to this Subscription Agreement has been made by Subscriber independently of any Other Subscriber or any other
investor and independently of any information, materials, statements or opinions as to the business, affairs, operations, assets, properties, liabilities, results of operations, condition (financial or otherwise) or prospects of the Company or any
of its subsidiaries which may have been made or given by any Other Subscriber or investor or by any agent or employee of any Other Subscriber or investor, and neither 

  
 27 

 
Subscriber nor any of its agents or employees shall have any liability to any Other Subscriber or investor (or any other person) relating to or arising from any such information, materials,
statements or opinions. Nothing contained herein or in any Other Subscription Agreement, and no action taken by Subscriber or investor pursuant hereto or thereto, shall be deemed to constitute Subscriber and other investors as a partnership, an
association, a joint venture or any other kind of entity, or create a presumption that Subscriber and other investors are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by the this
Subscription Agreement and the Other Subscription Agreements. Subscriber acknowledges that no Other Subscriber has acted as agent for Subscriber in connection with making its investment hereunder and no Other Subscriber will be acting as agent of
Subscriber in connection with monitoring its investment in the Subscribed Shares and the Warrants or enforcing its rights under this Subscription Agreement. Subscriber shall be entitled to independently protect and enforce its rights, including
without limitation the rights arising out of this Subscription Agreement, and it shall not be necessary for any Other Subscriber or investor to be joined as an additional party in any proceeding for such purpose. 

[Signature pages follow.] 

  
 28 

 IN WITNESS WHEREOF, each of the Company and Subscriber has executed or caused this
Subscription Agreement to be executed by its duly authorized representative as of the date first set forth above. 
  

			
	BROOKLINE CAPITAL ACQUISITION CORP.
	By:	 	      

		 	Name: Dr. Samuel Wertheimer
		 	Title: Chief Executive Officer and Chairman
	Address for Notices:
	 280 Park Avenue, Suite 43W

	 New York, NY 10017

Email:***

 Signature Page to Brookline Capital Acquisition Corp. Subscription Agreement 

			
	 SUBSCRIBER:
 Signature of Subscriber:

 
 By: ______________________________

Name:
 Title:
	  	
	Date: __________________________	  	
	 Name of Subscriber:
  

_______________________________
 (Please print. Please indicate
name and
 capacity of person signing above)
	  	
	 _________________________________
 Name in which
shares are to be registered
 (if different):
	  	
	Email Address: _______________________	  	
	 Subscriber’s EIN:

__________________________
	  	
	 Jurisdiction of residency: __________________________

 

			
	Number of Subscribed Shares subscribed for:	  	____________
	 Number of Warrants subscribed for:
  
	  	____________
	Price Per Subscribed Share:	  	$10.00
	Aggregate Purchase Price:	  	$____________

 You must pay the Purchase Price by wire transfer of United States dollars in immediately available funds to
the account of the Company specified by the Company in the Closing Notice. 
 Signature Page to Brookline Capital Acquisition Corp.
Subscription Agreement 
  

 ANNEX A 

ELIGIBILITY REPRESENTATIONS OF SUBSCRIBER 

This Annex A should be completed and signed by Subscriber 

and constitutes a part of the Subscription Agreement. 
  

	A.	 QUALIFIED INSTITUTIONAL BUYER STATUS (Please check the box, if applicable) 

 

	 	☐	 Subscriber is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act).

  

	B.	 FINRA INSTITUTIONAL INVESTOR STATUS (Please check the box) 

 

	 	☐	 Subscriber is a “institutional investor” (as defined in FINRA Rule 2111). 

 

	C.	 ACCREDITED INVESTOR STATUS (Please check the box) 

 

	 	☐	 Subscriber is an “accredited investor” (within the meaning of Rule 501(a) under the Securities Act)
and has marked and initialed the appropriate box below indicating the provision under which it qualifies as an “accredited investor.” 

  

	D.	 AFFILIATE STATUS (Please check the applicable box) 

SUBSCRIBER: 
  

	 	☐	 is: 

  

	 	☐	 is not: 

an “affiliate” (as defined in Rule 144 under the Securities Act) of the Company or acting on behalf of an affiliate of the Company.

 Rule 501(a), in relevant part, states that an “accredited investor” shall mean any person who comes within any of the below
listed categories, or who the issuer reasonably believes comes within any of the below listed categories, at the time of the sale of the securities to that person. Subscriber has indicated, by marking and initialing the appropriate box below, the
provision(s) below which apply to Subscriber and under which Subscriber accordingly qualifies as an “accredited investor.” 
  

	 	☐	 Any bank, registered broker or dealer, insurance company, registered investment company, business development
company, or small business investment company; 

  

	 	☐	 Any plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of
a state or its political subdivisions for the benefit of its employees, if such plan has total assets in excess of $5,000,000; 

  

	 	☐	 Any employee benefit plan, within the meaning of the Employee Retirement Income Security Act of 1974, if a
bank, insurance company, or registered investment advisor makes the investment decisions, or if the plan has total assets in excess of $5,000,000; 

  

	 	☐	 Any corporation, similar business trust, partnership or any organization described in Section 501(c)(3) of
the Internal Revenue Code, not formed for the specific purpose of acquiring the securities offered, with total assets in excess of $5,000,000; 

  

	 	☐	 Any director, executive officer, or general partner of the issuer of the securities being offered or sold, or
any director, executive officer, or general partner of a general partner of that issuer; 

  
 A-1 

	 	☐	 Any natural person whose individual net worth, or joint net worth with that person’s spouse, at the time
of his purchase exceeds $1,000,000. For purposes of calculating a natural person’s net worth: (a) the person’s primary residence must not be included as an asset; (b) indebtedness secured by the person’s primary residence up
to the estimated fair market value of the primary residence must not be included as a liability (except that if the amount of such indebtedness outstanding at the time of calculation exceeds the amount outstanding 60 days before such time, other
than as a result of the acquisition of the primary residence, the amount of such excess must be included as a liability); and (c) indebtedness that is secured by the person’s primary residence in excess of the estimated fair market value
of the residence must be included as a liability; 

  

	 	☐	 Any natural person who had an individual income in excess of $200,000 in each of the two most recent years or
joint income with that person’s spouse in excess of $300,000 in each of those years and has a reasonable expectation of reaching the same income level in the current year. 

 

	 	☐	 Any trust with assets in excess of $5,000,000, not formed to acquire the securities offered, whose purchase is
directed by a sophisticated person; or 

  

	 	☐	 Any entity in which all of the equity owners are accredited investors meeting one or more of the above tests.

  

	E.	 FINRA INSTITUTIONAL ACCOUNT STATUS 

(Please check the applicable subparagraphs): 
  

	 	☐	 Subscriber is an “institutional account” under FINRA Rule 4512(c). 

 

	 	☐	 Subscriber is not an “institutional account” under FINRA Rule 4512(c). 

 

	
	SUBSCRIBER:
	Print Name:
	By:
	Name:
	Title:

  
 A-2

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