Document:

EX-10.5

 Exhibit 10.5 

PURCHASE AGREEMENT 

THIS PURCHASE AGREEMENT (the “Agreement”), dated as of March 17, 2022 by and among BROOKLINE CAPITAL
ACQUISITION CORP., a Delaware corporation (the “Company”), APEXIGEN, INC., a Delaware corporation (“Apexigen”) and LINCOLN PARK CAPITAL FUND, LLC, an Illinois limited liability company (the
“Investor”). 
 WHEREAS: 

Pursuant to that certain Business Combination Agreement by and among the Company, Apexigen, and BCAC Merger Sub Inc., a wholly owned
subsidiary of the Company (“Merger Sub”) dated as of March 17, 2022, the Company and Apexigen intend to effect a merger of Merger Sub with and into Apexigen (the “Merger”) and, upon consummation of the Merger,
Merger Sub will cease to exist and Apexigen will become a wholly owned subsidiary of the Company. 
 From and after the Merger, and subject
to the terms and conditions set forth in this Agreement, the Company wishes to sell to the Investor, and the Investor wishes to purchase from the Company, up to Fifty Million Dollars ($50,000,000) of the Company’s common stock, par value
$0.0001 per share (the “Common Stock”). The shares of Common Stock to be purchased hereunder are referred to herein as the “Purchase Shares.” 

NOW THEREFORE, in consideration of the mutual covenants contained in this Agreement, and for other good and valuable consideration, the
receipt and adequacy of which are hereby acknowledged, the Company, Apexigen, and the Investor hereby agree as follows: 
  

	1.	 CERTAIN DEFINITIONS. 

For purposes of this Agreement, the following terms shall have the following meanings: 

(a) “Accelerated Purchase Date” means, with respect to any Accelerated Purchase made pursuant to
Section 2(b) hereof, the Business Day immediately following the applicable Purchase Date with respect to the corresponding Regular Purchase referred to in Section 2(b) hereof. 

(b) “Accelerated Purchase Minimum Price Threshold” means, with respect to any Accelerated Purchase made pursuant to
Section 2(b) hereof, any minimum per share price threshold set forth in the applicable Accelerated Purchase Notice. 

(c) “Accelerated Purchase Notice” means, with respect to any Accelerated Purchase made pursuant to
Section 2(b) hereof, an irrevocable written notice from the Company to the Investor directing the Investor to purchase a specified Accelerated Purchase Share Amount on the applicable Accelerated Purchase Date pursuant to
Section 2(b) hereof at the applicable Accelerated Purchase Price. 
 (d) “Accelerated Purchase
Price” means, with respect to any particular Accelerated Purchase made pursuant to Section 2(b) hereof, ninety-five percent (95%) of the lower of (i) the VWAP for the period beginning at 9:30:01 a.m., Eastern
time, on the applicable Accelerated Purchase Date, or such other time publicly announced by the Principal Market as the official open (or commencement) of trading on the Principal Market on such applicable Accelerated Purchase Date (the
“Accelerated Purchase Commencement Time”), and ending at the earliest of (A) 4:00:00 p.m., Eastern time, on such applicable Accelerated Purchase Date, or such other time publicly announced by Principal Market as the official close
of trading on the Principal Market on such applicable Accelerated Purchase Date, (B) such time, from and after the Accelerated Purchase Commencement Time for such Accelerated Purchase, that the total number 

 (or volume) of shares of Common Stock traded on the Principal Market has exceeded the applicable Accelerated
Purchase Share Volume Maximum, and (C) such time, from and after the Accelerated Purchase Commencement Time for such Accelerated Purchase, that the Sale Price has fallen below the applicable Accelerated Purchase Minimum Price Threshold (such
earliest of (i)(A), (i)(B) and (i)(C) above, the “Accelerated Purchase Termination Time”), and (ii) the Closing Sale Price of the Common Stock on such applicable Accelerated Purchase Date. 

(e) “Accelerated Purchase Share Amount” means, with respect to an Accelerated Purchase made pursuant to
Section 2(b) hereof, the number of Purchase Shares directed by the Company to be purchased by the Investor in such Accelerated Purchase Notice, which number of Purchase Shares shall not exceed the lesser of (i) 300% of the
number of Purchase Shares directed by the Company to be purchased by the Investor pursuant to the corresponding Regular Purchase Notice for the corresponding Regular Purchase referred to in clause (i) of the second sentence of
Section 2(b) hereof (subject to the Purchase Share limitations contained in Section 2(a) hereof) and (ii) an amount equal to (A) the Accelerated Purchase Share Percentage multiplied by
(B) the total number (or volume) of shares of Common Stock traded on the Principal Market during the period on the applicable Accelerated Purchase Date beginning at the Accelerated Purchase Commencement Time for such Accelerated Purchase and
ending at the Accelerated Purchase Termination Time for such Accelerated Purchase. 
 (f) “Accelerated Purchase Share
Percentage” means, with respect to any Accelerated Purchase made pursuant to Section 2(b) hereof, thirty percent (30%). 

(g) “Accelerated Purchase Share Volume Maximum” means, with respect to an Accelerated Purchase made pursuant to
Section 2(b) hereof, a number of shares of Common Stock equal to (i) the applicable Accelerated Purchase Share Amount to be purchased by the Investor pursuant to the applicable Accelerated Purchase Notice for such
Accelerated Purchase, divided by (ii) the Accelerated Purchase Share Percentage. 
 (h) “Additional Accelerated Purchase
Date” means, with respect to an Additional Accelerated Purchase made pursuant to Section 2(c) hereof, the Business Day (i) that is the Accelerated Purchase Date with respect to the corresponding Accelerated
Purchase referred to in Section 2(b) hereof and (ii) on which the Investor receives, prior to 1:00 p.m., Eastern time, on such Business Day, a valid Additional Accelerated Purchase Notice for such Additional
Accelerated Purchase in accordance with this Agreement. 
 (i) “Additional Accelerated Purchase Minimum Price Threshold”
means, with respect to an Additional Accelerated Purchase made pursuant to Section 2(c) hereof, any minimum per share price threshold set forth in the applicable Additional Accelerated Purchase Notice. 

(j) “Additional Accelerated Purchase Notice” means, with respect to an Additional Accelerated Purchase made pursuant to
Section 2(c) hereof, an irrevocable written notice from the Company to the Investor directing the Investor to purchase the applicable Additional Accelerated Purchase Share Amount at the Additional Accelerated Purchase Price
for such Additional Accelerated Purchase in accordance with this Agreement. 
 (k) “Additional Accelerated Purchase Price”
means, with respect to an Additional Accelerated Purchase made pursuant to Section 2(c) hereof, ninety-five percent (95%) of the lower of (i) of the VWAP for the period on the applicable Additional Accelerated Purchase
Date, beginning at the latest of (A) the applicable Accelerated Purchase Termination Time with respect to the corresponding Accelerated Purchase referred to in Section 2(b) hereof on such Additional Accelerated
Purchase Date, (B) the applicable Additional Accelerated Purchase Termination Time with respect to the most recently completed prior Additional Accelerated Purchase on such Additional Accelerated Purchase Date, as applicable, and (C) the

  
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time at which all Purchase Shares subject to all prior Accelerated Purchases and Additional Accelerated Purchases (as applicable), including, without limitation, those that have been effected on
the same Business Day as the applicable Additional Accelerated Purchase Date with respect to which the applicable Additional Accelerated Purchase relates, and have theretofore been received by the Investor as DWAC Shares in accordance with this
Agreement (such latest of (i)(A), (i)(B) and (i)(C) above, the “Additional Accelerated Purchase Commencement Time”), and ending at the earliest of (X) 4:00 p.m., Eastern time, on such Additional Accelerated Purchase Date, or such
other time publicly announced by Principal Market as the official close of trading on the Principal Market on such Additional Accelerated Purchase Date, (Y) such time, from and after the Additional Accelerated Purchase Commencement Time for
such Additional Accelerated Purchase, that total number (or volume) of shares of Common Stock traded on the Principal Market has exceeded the applicable Additional Accelerated Purchase Share Volume Maximum, and (Z) such time, from and after the
Additional Accelerated Purchase Commencement Time for such Additional Accelerated Purchase, that the Sale Price has fallen below the applicable Additional Accelerated Purchase Minimum Price Threshold (if any) (such earliest of (i)(X), (i)(Y) and
(i)(Z) above, the “Additional Accelerated Purchase Termination Time”), and (ii) the Closing Sale Price of the Common Stock on such Additional Accelerated Purchase Date. 

(l) “Additional Accelerated Purchase Share Amount” means, with respect to an Additional Accelerated Purchase made pursuant to
Section 2(c) hereof, the number of Purchase Shares directed by the Company to be purchased by the Investor on an Additional Accelerated Purchase Notice, which number of Purchase Shares shall not exceed the lesser of (i)
300% of the number of Purchase Shares directed by the Company to be purchased by the Investor pursuant to the corresponding Regular Purchase Notice for the corresponding Regular Purchase referred to in clause (i) of the second sentence of
Section 2(c) hereof (subject to the Purchase Share limitations contained in Section 2(a) hereof) and (ii) an amount equal to (A) the Additional Accelerated Purchase Share Percentage
multiplied by (B) the total number (or volume) of shares of Common Stock traded on the Principal Market during the period on the applicable Additional Accelerated Purchase Date beginning at the Additional Accelerated Purchase Commencement Time
for such Additional Accelerated Purchase and ending at the Additional Accelerated Purchase Termination Time for such Additional Accelerated Purchase. 

(m) “Additional Accelerated Purchase Share Percentage” means, with respect to an Additional Accelerated Purchase made
pursuant to Section 2(c) hereof, thirty percent (30%). 
 (n) “Additional Accelerated Purchase Share
Volume Maximum” means, with respect to an Additional Accelerated Purchase made pursuant to Section 2(c) hereof, a number of shares of Common Stock equal to (i) the applicable Additional Accelerated Purchase
Share Amount to be purchased by the Investor pursuant to the applicable Additional Accelerated Purchase Notice for such Additional Accelerated Purchase, divided by (ii) the Additional Accelerated Purchase Share Percentage. 

(o) “Available Amount” means, initially, Fifty Million Dollars ($50,000,000) in the aggregate, which amount shall be reduced
by the Purchase Amount each time the Investor purchases shares of Common Stock pursuant to Section 2 hereof. 

(p) “Average Price” means a price per Purchase Share (rounded to the nearest tenth of a cent) equal to the quotient obtained
by dividing (i) the aggregate gross purchase price paid by the Investor for all Purchase Shares purchased pursuant to this Agreement, by (ii) the aggregate number of Purchase Shares issued pursuant to this Agreement. 

(q) “Bankruptcy Law” means Title 11, U.S. Code, or any similar federal or state law for the relief of debtors. 

  
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 (r) “Business Day” means any day on which the Principal Market is open for
trading, including any day on which the Principal Market is open for trading for a period of time less than the customary time. 
 (s)
“Apexigen Material Adverse Effect” means any material adverse effect on (i) the enforceability of any Transaction Document, (ii) the results of operations, assets, business or financial condition of Apexigen, other than
any material adverse effect that resulted primarily from (A) any change in the United States or foreign economies or securities or financial markets in general that does not have a disproportionate effect on Apexigen, (B) any change that
generally affects the industry in which Apexigen operates that does not have a disproportionate effect on Apexigen, (C) any change arising in connection with earthquakes, hostilities, acts of war, sabotage or terrorism or military actions or
any escalation or material worsening of any such hostilities, acts of war, sabotage or terrorism or military actions existing as of the date hereof, (D) any action taken by the Investor, its affiliates or its or their successors and assigns
with respect to the transactions contemplated by this Agreement, (E) the effect of any change in applicable laws or accounting rules that does not have a disproportionate effect on Apexigen, or (F) any change resulting from compliance with
terms of this Agreement or the consummation of the transactions contemplated by this Agreement, or (iii) Apexigen’s ability to perform in any material respect on a timely basis its obligations under any Transaction Document to be performed
as of the date of determination. 
 (t) “Closing Sale Price” means, for any security as of any date, the last closing sale
price on such date for such security on the Principal Market as reported by the Principal Market. 
 (u) “Company Material Adverse
Effect” means any material adverse effect on (i) the enforceability of any Transaction Document, (ii) the results of operations, assets, business or financial condition of the Company and its Subsidiaries, taken as a whole, other
than any material adverse effect that resulted primarily from (A) any change in the United States or foreign economies or securities or financial markets in general that does not have a disproportionate effect on the Company and its
Subsidiaries, taken as a whole, (B) any change that generally affects the industry in which the Company and its Subsidiaries operate that does not have a disproportionate effect on the Company and its Subsidiaries, taken as a whole,
(C) any change arising in connection with earthquakes, hostilities, acts of war, sabotage or terrorism or military actions or any escalation or material worsening of any such hostilities, acts of war, sabotage or terrorism or military actions
existing as of the date hereof, (D) any action taken by the Investor, its affiliates or its or their successors and assigns with respect to the transactions contemplated by this Agreement, (E) the effect of any change in applicable laws or
accounting rules that does not have a disproportionate effect on the Company and its Subsidiaries, taken as a whole, or (F) any change resulting from compliance with terms of this Agreement or the consummation of the transactions contemplated
by this Agreement, or (iii) the Company’s ability to perform in any material respect on a timely basis its obligations under any Transaction Document to be performed as of the date of determination. 

(v) “Confidential Information” means any information disclosed by either party to the other party, either directly or
indirectly, in writing, orally or by inspection of tangible objects (including, without limitation, documents, prototypes, samples, plant and equipment), which is designated as “Confidential,” “Proprietary” or some similar
designation. Information communicated orally shall be considered Confidential Information if such information is confirmed in writing as being Confidential Information within ten (10) Business Days after the initial disclosure. Confidential
Information may also include information disclosed to a disclosing party by third parties. Confidential Information shall not, however, include any information which (i) was publicly known and made generally available in the public domain prior
to the time of disclosure by the disclosing party; (ii) becomes publicly known and made generally available after disclosure by the disclosing party to the receiving party through no action or inaction of the receiving party; (iii) is
already in the possession of the receiving party without confidential restriction at the time of disclosure by the disclosing party as shown by the receiving party’s files and records 

  
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immediately prior to the time of disclosure; (iv) is obtained by the receiving party from a third party without a breach of such third party’s obligations of confidentiality;
(v) is independently developed by the receiving party without use of or reference to the disclosing party’s Confidential Information, as shown by documents and other competent evidence in the receiving party’s possession; or
(vi) is required by law to be disclosed by the receiving party, provided that (X) the receiving party (1) gives the disclosing party prompt written notice of such requirement prior to such disclosure and assistance in obtaining an
order protecting the information from public disclosure and (2) furnishes only that portion of the Confidential Information that is legally required to be disclosed, and (Y) any Confidential Information so disclosed shall maintain its
confidentiality protection for all purposes other than such legally compelled disclosure. 
 (w) “Custodian” means any
receiver, trustee, assignee, liquidator or similar official under any Bankruptcy Law. 
 (x) “DTC” means The Depository
Trust Company, or any successor performing substantially the same function for the Company. 
 (y) “DWAC Shares” means
shares of Common Stock that are (i) issued in electronic form, (ii) freely tradable and transferable and without restriction on resale and (iii) timely credited, once a DWAC notice is received, by the Company to the Investor’s or
its designee’s specified Deposit/Withdrawal at Custodian (DWAC) account with DTC under its Fast Automated Securities Transfer (FAST) Program, or any similar program hereafter adopted by DTC performing substantially the same function. 

(z) “Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated
thereunder. 
 (aa) “Floor Price” means $3.00, which shall be appropriately adjusted for any reorganization,
recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction and, effective upon the consummation of any such reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction (the “Adjusted Price”), the Floor Price shall mean the lower of (i) the Adjusted Price and (ii) $3.00. 

(bb) “Maturity Date” means the first day of the month immediately following the twenty-four (24) month anniversary of
the Commencement Date. 
 (cc) “PEA Period” means the period commencing at 9:30 a.m., Eastern time, on the tenth (10th)
Business Day immediately prior to the filing of any post-effective amendment to the Registration Statement (as defined herein) or New Registration Statement (as such term is defined in the Registration Rights Agreement), and ending at 9:30 a.m.,
Eastern time, on the Business Day immediately following, the effective date of any post-effective amendment to the Registration Statement (as defined in Section 5(a) below) or New Registration Statement (as such term is
defined in the Registration Rights Agreement). 
 (dd) “Person” means an individual or entity including but not limited to
any limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization and a government or any department or agency thereof. 

(ee) “Principal Market” means The Nasdaq Capital Market (or any nationally recognized successor thereto); provided, however,
that in the event the Company’s Common Stock is ever listed or traded on The Nasdaq Global Market, The Nasdaq Global Select Market, the New York Stock Exchange, the NYSE American, the NYSE Arca, the OTC Bulletin Board, the OTCQX operated by the
OTC Markets Group, Inc. or the OTCQB operated by the OTC Markets Group, Inc. (or any nationally recognized successor to any of the foregoing), then the “Principal Market” shall mean such other market or exchange on which the Company’s
Common Stock is then listed or traded. 

  
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 (ff) “Purchase Amount” means, with respect to any Regular Purchase, any
Accelerated Purchase or any Additional Accelerated Purchase made hereunder, the portion of the Available Amount to be purchased by the Investor pursuant to Section 2 hereof. 

(gg) “Purchase Date” means, with respect to any Regular Purchase made pursuant to Section 2(a)
hereof, the Business Day on which the Investor receives by 6:00 p.m., Eastern time, of such Business Day a valid Regular Purchase Notice that the Investor is to purchase such applicable dollar amount of Purchase Shares pursuant to
Section 2(a) hereof. 
 (hh) “Purchase Price” means, with respect to any Regular Purchase made
pursuant to Section 2(a) hereof, the lower of: (i) the lowest Sale Price on the applicable Purchase Date and (ii) the arithmetic average of the three (3) lowest Closing Sale Prices for the Common Stock during
the ten (10) consecutive Business Days ending on the Business Day immediately preceding such Purchase Date. 
 (ii)
“Registration Rights Agreement” means that certain Registration Rights Agreement, of even date herewith between the Company and the Investor. 

(jj) “Regular Purchase Notice” means, with respect to any Regular Purchase pursuant to Section 2(a)
hereof, an irrevocable written notice from the Company to the Investor directing the Investor to purchase such applicable amount of Purchase Shares at the applicable Purchase Price as specified by the Company therein on the applicable Purchase Date
for such Regular Purchase. 
 (kk) “Sale Price” means any trade price for the shares of Common Stock on the Principal
Market as reported by the Principal Market. 
 (ll) “SEC” means the U.S. Securities and Exchange Commission. 

(mm) “Securities” means, collectively, the Purchase Shares and the Commitment Shares (as defined in
Section 5(e) below). 
 (nn) “Securities Act” means the Securities Act of 1933, as amended, and
the rules and regulations promulgated thereunder. 
 (oo) “Signing Market Price” means $10.06, representing the lower of
(i) the closing price of the Common Stock on the Nasdaq Capital Market on the Business Day immediately preceding the date of this Agreement or (ii) the average of the closing price of the Common Stock on the Nasdaq Global Market for the
five Business Days immediately preceding the signing of this Agreement. 
 (pp) “Subsidiary” means any Person the Company
wholly-owns or controls, or in which the Company, directly or indirectly, owns a majority of the voting stock or similar voting interest, in each case that would be disclosable pursuant to Item 601(b)(21) of Regulation
S-K promulgated under the Securities Act. 
 (qq) “Transaction Documents” means,
collectively, this Agreement and the schedules and exhibits hereto, the Registration Rights Agreement and the schedules and exhibits thereto, and each of the other agreements, documents, certificates and instruments entered into or furnished by the
parties hereto in connection with the transactions contemplated hereby and thereby. 

  
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 (rr) “Transfer Agent” means Continental Stock Transfer & Trust, or
such other Person who is then serving as the transfer agent for the Company in respect of the Common Stock. 
 (ss) “VWAP”
means in respect of an applicable Accelerated Purchase Date and an Additional Accelerated Purchase Date, as applicable, the volume weighted average price of the Common Stock on the Principal Market, as reported on the Principal Market or by another
reputable source such as Bloomberg, L.P. 
  

	2.	 PURCHASE OF COMMON STOCK. 

Subject to the terms and conditions set forth in this Agreement, the Company has the right to sell to the Investor, and the Investor has the
obligation to purchase from the Company, Purchase Shares as follows: 
 (a) Commencement of Regular Sales of Common Stock. Following
the consummation of the Merger and upon the satisfaction of the conditions set forth in Sections 7 and 8 hereof (the “Commencement” and the date of satisfaction of such conditions the “Commencement Date”) and thereafter,
the Company shall have the right, but not the obligation, to direct the Investor, by its delivery to the Investor of a Regular Purchase Notice from time to time, to purchase up to Five Hundred Thousand Dollars ($500,000) of Purchase Shares subject
to adjustment as set forth below in this Section 2(a) (as it may be adjusted below, the “Regular Purchase Share Limit”), at the Purchase Price on the Purchase Date (each such purchase, a “Regular Purchase”);
provided, however, that (i) the Regular Purchase Share Limit shall be increased to up to Seven Hundred Fifty Thousand Dollars ($750,000) of Purchase Shares, provided that the Closing Sale Price of the Common Stock is not below $10.00 on such
Purchase Date (as appropriately adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction), and (ii) the Regular Purchase Share
Limit shall be increased to up to One Million Dollars ($1,000,000) of Purchase Shares, provided that the Closing Sale Price of the Common Stock is not below $12.50 on such Purchase Date. If the Company delivers any Regular Purchase Notice for a
Purchase Amount in excess of the limitations contained in the immediately preceding sentence, such Regular Purchase Notice shall be void ab initio to the extent, and only to the extent, of the amount by which the number of Purchase Shares set
forth in such Regular Purchase Notice exceeds the dollar amount (based on the applicable Purchase Price) of Purchase Shares which the Company is permitted to include in such Purchase Notice in accordance herewith, and the Investor shall have no
obligation to purchase such excess Purchase Shares in respect of such Regular Purchase Notice; provided that the Investor shall remain obligated to purchase the dollar amount (based on the applicable Purchase Price) of Purchase Shares which the
Company is permitted to include in such Regular Purchase Notice. The Company may deliver Regular Purchase Notices to the Investor as often as every Business Day, so long as (i) the Closing Sale Price of the Common Stock on such Business Day is
not less than the Floor Price and (ii) the Company has not failed to deliver Purchase Shares for all prior Regular Purchases, Accelerated Purchases and Additional Accelerated Purchases, including, without limitation, those that have been
effected on the same Business Day as the applicable Purchase Date, have theretofore been received by, the Investor as DWAC Shares in accordance with this Agreement. Notwithstanding the foregoing, the Company shall not deliver any Regular Purchase
Notices during the PEA Period. 
 (b) Accelerated Purchases. Subject to the terms and conditions of this Agreement, from and after
the Commencement Date, in addition to purchases of Purchase Shares as described in Section 2(a) above, the Company shall also have the right, but not the obligation, to direct the Investor by the Company’s delivery to
the Investor of an Accelerated Purchase Notice from time to time, and the Investor thereupon shall have the obligation, to purchase such applicable number of Purchase Shares at the Accelerated Purchase Price on the Accelerated Purchase Date in an
amount up to the Accelerated Purchase Share Amount in accordance with this Agreement (each such purchase, an “Accelerated Purchase”). The 

  
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Company may deliver an Accelerated Purchase Notice to the Investor only on a Purchase Date on which (i) the Company also properly submitted a Regular Purchase Notice providing for a Regular
Purchase of a number of Purchase Shares not less than the Regular Purchase Share Limit then in effect on such Purchase Date in accordance with this Agreement (including, without limitation, giving effect to any increase to the Regular Purchase Share
Limit as a result of the Closing Sale Price of the Common Stock exceeding certain thresholds set forth in Section 2(a) above on such Purchase Date and any other adjustments to the Regular Purchase Share Limit, in each case
pursuant to Section 2(a) above), (ii) if all Purchase Shares subject to all prior Regular Purchases, Accelerated Purchases and Additional Accelerated Purchases, including, without limitation, those that have been effected
on the same Business Day as the applicable Accelerated Purchase Date with respect to which the applicable Accelerated Purchase relates, have theretofore been received by the Investor as DWAC Shares in accordance with this Agreement and
(iii) the Closing Sale Price is not less than the Floor Price. If the Company delivers any Accelerated Purchase Notice directing the Investor to purchase an amount of Purchase Shares that exceeds the Accelerated Purchase Share Amount that the
Company is then permitted to include in such Accelerated Purchase Notice, such Accelerated Purchase Notice shall be void ab initio to the extent, and only to the extent, of the number by which the number of Purchase Shares set forth in such
Accelerated Purchase Notice exceeds the Accelerated Purchase Share Amount which the Company is permitted to include in such Accelerated Purchase Notice in accordance herewith (which shall be confirmed in an Accelerated Purchase Confirmation (defined
below)), and the Investor shall have no obligation to purchase such excess Purchase Shares in respect of such Accelerated Purchase Notice; provided that the Investor shall remain obligated to purchase the Accelerated Purchase Share Amount which the
Company is permitted to include in such Accelerated Purchase Notice. Within one (1) Business Day after completion of each Accelerated Purchase Date, the Accelerated Purchase Share Amount and the applicable Accelerated Purchase Price shall be
set forth on a written confirmation of the Accelerated Purchase to be provided to the Company by the Investor (an “Accelerated Purchase Confirmation”). Notwithstanding the foregoing, the Company shall not deliver any Accelerated
Purchase Notices during the PEA Period. 
 (c) Additional Accelerated Purchases. Subject to the terms and conditions of this
Agreement, beginning one (1) Business Day following the Commencement Date and thereafter, in addition to purchases of Purchase Shares as described in Section 2(a) and Section 2(b) above, the
Company shall also have the right, but not the obligation, to direct the Investor, by its timely delivery to the Investor of an Additional Accelerated Purchase Notice on an Additional Accelerated Purchase Date in accordance with this Agreement, to
purchase the applicable Additional Accelerated Purchase Share Amount at the applicable Additional Accelerated Purchase Price therefor in accordance with this Agreement (each such purchase, an “Additional Accelerated Purchase”). The
Company may deliver multiple Additional Accelerated Purchase Notices to the Investor on an Additional Accelerated Purchase Date; provided, however, that the Company may deliver an Additional Accelerated Purchase Notice to the Investor only
(i) on a Business Day that is also the Accelerated Purchase Date for an Accelerated Purchase with respect to which the Company properly submitted to the Investor an Accelerated Purchase Notice in accordance with this Agreement on the applicable
Purchase Date for a Regular Purchase of a number of Purchase Shares not less than the Regular Purchase Share Limit then in effect in accordance with this Agreement (including, without limitation, giving effect to any automatic increase to the
Regular Purchase Share Limit as a result of the Closing Sale Price of the Common Stock exceeding certain thresholds set forth in Section 2(a) above on such Purchase Date and any other adjustments to the Regular Purchase
Share Limit, in each case pursuant to Section 2(a) above), (ii) if the Closing Sale Price of the Common Stock on the Business Day immediately preceding the Business Day on which such Additional Accelerated Purchase Notice
is delivered is not less than the Floor Price, and (iii) if all Purchase Shares subject to all prior Regular Purchases, Accelerated Purchases and Additional Accelerated Purchases, including, without limitation, those that have been effected on
the same Business Day as the applicable Additional Accelerated Purchase Date with respect to which the applicable Additional Accelerated Purchase relates, have theretofore been received by the Investor as DWAC Shares in accordance with this
Agreement. If the Company delivers any Additional 

  
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Accelerated Purchase Notice directing the Investor to purchase an amount of Purchase Shares that exceeds the Additional Accelerated Purchase Share Amount that the Company is then permitted to
include in such Additional Accelerated Purchase Notice in accordance with the terms of this Agreement, such Additional Accelerated Purchase Notice shall be void ab initio to the extent, and only to the extent, of the number by which the
number of Purchase Shares set forth in such Additional Accelerated Purchase Notice exceeds the Additional Accelerated Purchase Share Amount that the Company is then permitted to include in such Additional Accelerated Purchase Notice in accordance
with the terms of this Agreement (which shall be confirmed in an Additional Accelerated Purchase Confirmation (defined below)), and the Investor shall have no obligation to purchase such excess Purchase Shares in respect of such Additional
Accelerated Purchase Notice; provided, however, that the Investor shall remain obligated to purchase the Additional Accelerated Purchase Share Amount which the Company is permitted to include in such Additional Accelerated Purchase Notice. Within
one (1) Business Day after completion of each Additional Accelerated Purchase Date, the Investor will provide to the Company a written confirmation of each Additional Accelerated Purchase on such Additional Accelerated Purchase Date setting
forth the applicable Additional Accelerated Purchase Share Amount and Additional Accelerated Purchase Price for each such Additional Accelerated Purchase on such Additional Accelerated Purchase Date (each, an “Additional Accelerated Purchase
Confirmation”). Notwithstanding the foregoing, the Company shall not deliver any Additional Accelerated Purchase Notices during the PEA Period. 

(d) Payment for Purchase Shares. For each Regular Purchase, the Investor shall pay to the Company an amount equal to the Purchase
Amount with respect to such Regular Purchase as full payment for such Purchase Shares via wire transfer of immediately available funds on the same Business Day that the Investor receives such Purchase Shares, if such Purchase Shares are received by
the Investor before 1:00 p.m., Eastern time, or, if such Purchase Shares are received by the Investor after 1:00 p.m., Eastern time, the next Business Day. For each Accelerated Purchase and each Additional Accelerated Purchase, the Investor pay to
the Company an amount equal to the Purchase Amount with respect to such Accelerated Purchase and Additional Accelerated Purchase, respectively, as full payment for such Purchase Shares via wire transfer of immediately available funds on the second
Business Day following the date that the Investor receives such Purchase Shares. If the Company or the Transfer Agent shall fail for any reason or for no reason to electronically transfer any Purchase Shares as DWAC Shares in respect of a Regular
Purchase, an Accelerated Purchase or an Additional Accelerated Purchase (as applicable) within two (2) Business Days following the receipt by the Company of the Purchase Price, Accelerated Purchase Price and Additional Accelerated Purchase
Price, respectively, therefor in compliance with this Section 2(d), and if on or after such Business Day the Investor purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction
of a sale by the Investor of such Purchase Shares that the Investor anticipated receiving from the Company in respect of such Regular Purchase, Accelerated Purchase or Additional Accelerated Purchase (as applicable), then the Company shall, within
two (2) Business Days after the Investor’s request, either (i) pay cash to the Investor in an amount equal to the Investor’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so
purchased (the “Cover Price”), at which point the Company’s obligation to deliver such Purchase Shares as DWAC Shares shall terminate, or (ii) promptly honor its obligation to deliver to the Investor such Purchase Shares
as DWAC Shares and pay cash to the Investor in an amount equal to the excess (if any) of the Cover Price over the total Purchase Amount paid by the Investor pursuant to this Agreement for all of the Purchase Shares to be purchased by the Investor in
connection with such Regular Purchase, Accelerated Purchase and Additional Accelerated Purchase (as applicable). If the issuance would result in the issuance of a fraction of a share of Common Stock, the Company shall round such fraction of a share
of Common Stock up or down to the nearest whole share. All payments made under this Agreement shall be made in lawful money of the United States of America or wire transfer of immediately available funds to such account as the Company may from time
to time designate by written notice in accordance with the provisions of this Agreement. Whenever any amount expressed to be due by the terms of this Agreement is due on any day that is not a Business Day, the same shall instead be due on the next
succeeding day that is a Business Day. 

  
 9 

 (e) Beneficial Ownership Limitation. Notwithstanding anything to the contrary
contained in this Agreement, the Company shall not issue or sell, and the Investor shall not purchase or acquire, any shares of Common Stock under this Agreement which, when aggregated with all other shares of Common Stock then beneficially owned by
the Investor and its affiliates (as calculated pursuant to Section 13(d) of the Exchange Act and Rule 13d-3 promulgated thereunder), would result in the beneficial ownership by the Investor and its
affiliates of more than 4.99% of the then issued and outstanding shares of Common Stock (the “Beneficial Ownership Limitation”). Upon the written or oral request of the Investor, the Company shall promptly confirm orally or in
writing to the Investor the number of shares of Common Stock then outstanding. The Investor and the Company shall each cooperate in good faith in the determinations required hereby and the application hereof. The Investor’s written
certification to the Company of the applicability of the Beneficial Ownership Limitation, and the resulting effect thereof hereunder at any time, shall be conclusive with respect to the applicability thereof and such result absent manifest error.

 (f) Compliance with Principal Market Rules. 

(i) Exchange Cap. Subject to Section 2(f)(ii) below, the Company shall not issue or sell any shares of Common
Stock pursuant to this Agreement, and the Investor shall not purchase or acquire any shares of Common Stock pursuant to this Agreement, to the extent that after giving effect thereto, the aggregate number of shares of Common Stock that would be
issued pursuant to this Agreement and the transactions contemplated hereby would be equal to or greater than a number shares of Common Stock representing 19.99% of the shares of Common Stock outstanding on the date of this Agreement (which number of
shares shall be reduced, on a share-for-share basis, by the number of shares of Common Stock issued or issuable pursuant to any transaction or series of transactions
that may be aggregated with the transactions contemplated by this Agreement under applicable rules of The Nasdaq Capital Market or any other Principal Market on which the Common Stock may be listed or quoted) (the “Exchange Cap”),
unless stockholder approval is obtained to issue in excess of the Exchange Cap; provided, however, that the foregoing limitation shall not apply if at any time the Exchange Cap is reached and at all times thereafter the average price paid for all
shares of Common Stock issued under this Agreement is equal to or greater than $10.06 (the “Minimum Price”), a price equal to the lower of (i) the Nasdaq Official Closing Price (as defined by the Principal Market and as
reflected on www.nasdaq.com) immediately preceding the execution of this Agreement or (ii) the arithmetic average of the five (5) Nasdaq Official Closing Prices for the Common Stock immediately preceding the execution of this Agreement, as
calculated in accordance with the rules of the Principal Market (in such circumstance, for purposes of the Principal Market, the transaction contemplated hereby would not be “below market” and the Exchange Cap would not apply).
Notwithstanding the foregoing, the Company shall not be required or permitted to issue, and the Investor shall not be required to purchase, any shares of Common Stock under this Agreement if such issuance would violate the rules or regulations of
the Principal Market. 
 (ii) General. The Company shall not issue any Securities pursuant to this Agreement if such issuance would
reasonably be expected to result in (A) a violation of the Securities Act or (B) a breach of the rules and regulations of the Principal Market. Furthermore, the Company agrees that it shall not issue any Securities pursuant to this
Agreement if, at the time of such issuance (Y) the effectiveness of the Registration Statement registering the Securities has lapsed for any reason (including, without limitation, the issuance of a stop order or similar order) or (Z) the
Registration Statement is unavailable for the sale by the Company to the Investor (or the resale by the Investor, as the case may be) of any or all of the Securities to be issued to the Investor under the Transaction Documents. The provisions of
this Section 2(f) shall be implemented in a manner otherwise than in strict conformity with the terms hereof only if necessary to ensure compliance with the Securities Act and the rules and regulations of the Principal
Market. 

  
 10 

	3.	 INVESTOR’S REPRESENTATIONS AND WARRANTIES. 

The Investor represents and warrants to the Company and Apexigen that as of the date hereof and as of the Commencement Date: 

(a) Organization; Authority. The Investor is an entity duly organized, validly existing and in good standing under the laws of the
jurisdiction of its organization, with the requisite power and authority to enter into and to consummate the transactions contemplated by this Agreement and otherwise to carry out its obligations hereunder and thereunder. 

(b) Investment Purpose. The Investor is acquiring the Securities as principal for its own account and not with a view to or for
distributing or reselling such Securities or any part thereof in violation of the Securities Act or any applicable state securities law, has no present intention of distributing any of such Securities in violation of the Securities Act or any
applicable state securities law and has no direct or indirect arrangement or understandings with any other Persons to distribute or regarding the distribution of such Securities in violation of the Securities Act or any applicable state securities
law (this representation and warranty not limiting the Investor’s right to sell the Securities at any time pursuant to the Registration Statement described herein or otherwise in compliance with applicable federal and state securities laws).
The Investor is acquiring the Securities hereunder in the ordinary course of its business. 
 (c) Accredited Investor Status. The
Investor is an “accredited investor” as that term is defined in Rule 501(a)(3) of Regulation D promulgated under the Securities Act. 

(d) Reliance on Exemptions. The Investor understands that the Securities may be offered and sold to it in reliance on specific
exemptions from the registration requirements of United States federal and state securities laws and that each of the Company and Apexigen is relying in part upon the truth and accuracy of, and the Investor’s compliance with, the
representations, warranties, agreements, acknowledgments and understandings of the Investor set forth herein in order to determine the availability of such exemptions and the eligibility of the Investor to acquire the Securities. 

(e) Information. The Investor understands that its investment in the Securities involves a high degree of risk. The Investor
(i) is able to bear the economic risk of an investment in the Securities including a total loss thereof, (ii) has such knowledge and experience in financial and business matters that it is capable of evaluating the merits and risks of the
proposed investment in the Securities and (iii) has had an opportunity to ask questions of and receive answers from the officers of each of the Company and Apexigen concerning the financial condition and business of the Company and Apexigen and
other matters related to an investment in the Securities. Neither such inquiries nor any other due diligence investigations conducted by the Investor or its representatives shall modify, amend or affect the Investor’s right to rely on the
Company’s and Apexigen’s representations and warranties contained in Section 4 below. The Investor has sought such accounting, legal and tax advice from its own independent advisor as it has considered necessary
to make an informed investment decision with respect to its acquisition of the Securities. The Investor understands that it (and not the Company or Apexigen) shall be responsible for its own tax liabilities that may arise as a result of this
investment or the transactions contemplated by this Agreement. 
 (f) No Governmental Review. The Investor understands that no U.S.
federal or state agency or any other government or governmental agency has passed on or made any recommendation or endorsement of the Securities or the fairness or suitability of an investment in the Securities nor have such authorities passed upon
or endorsed the merits of the offering of the Securities. 

  
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 (g) Transfer or Sale. The Investor understands that (i) the Securities may not
be offered for sale, sold, assigned or transferred unless (A) registered pursuant to the Securities Act or (B) an exemption exists permitting such Securities to be sold, assigned or transferred without such registration; (ii) any sale
of the Securities made in reliance on Rule 144 promulgated under the Securities Act (“Rule 144”) may be made only in accordance with the terms of Rule 144 and further, if Rule 144 is not applicable, any resale of the Securities
under circumstances in which the seller (or the Person through whom the sale is made) may be deemed to be an underwriter (as that term is defined in the Securities Act) may require compliance with some other exemption under the Securities Act or the
rules and regulations of the SEC thereunder. 
 (h) Validity; Enforcement. This Agreement and the Registration Rights Agreement has
been, and each other Transaction Document shall be on the Commencement Date, duly and validly authorized, executed and delivered on behalf of the Investor and each is a valid and binding agreement of the Investor enforceable against the Investor in
accordance with its terms, subject as to enforceability to general principles of equity and to applicable bankruptcy, insolvency, reorganization, moratorium, liquidation and other similar laws relating to, or affecting generally, the enforcement of
applicable creditors’ rights and remedies. 
 (i) Residency. The Investor is a resident of the State of Illinois. 

(j) No Short Selling. The Investor represents and warrants to the Company and Apexigen that at no time prior to the date of this
Agreement has any of the Investor, its agents, representatives or affiliates engaged in or effected, in any manner whatsoever, directly or indirectly, any (i) “short sale” (as such term is defined in Rule 200 of Regulation SHO of the
Exchange Act) of the Common Stock or (ii) hedging transaction, which establishes a net short position with respect to the Common Stock. 
  

	4.	 REPRESENTATIONS AND WARRANTIES OF THE COMPANY AND APEXIGEN. 

(a) Company Representations and Warranties. The Company represents and warrants to the Investor that, except as set forth in the
disclosure schedules attached hereto, which exceptions shall be deemed to be a part of the representations and warranties made hereunder, as of the date hereof and as of the Commencement Date: 

(i) Organization and Qualification. The Company and each of its Subsidiaries is an entity duly incorporated or otherwise organized,
validly existing and in good standing under the laws of the jurisdiction of its incorporation or organization, with the requisite corporate power and authority to own and use its properties and assets and to carry on its business as currently
conducted. Neither the Company nor any of its Subsidiaries is in violation or default of any of the provisions of its respective articles or certificate of incorporation, bylaws or other organizational or charter documents. Each of the Company and
its Subsidiaries is duly qualified to conduct business and is in good standing as a foreign corporation or other entity in each jurisdiction in which the nature of the business conducted or property owned by it makes such qualification necessary,
except where the failure to be so qualified or in good standing, as the case may be, could not have or reasonably be expected to result in a Company Material Adverse Effect and no proceeding has been instituted in any such jurisdiction revoking,
limiting or curtailing or seeking to revoke, limit or curtail such power and authority or qualification. The Company has no Subsidiaries except (1) as set forth in the Company’s Amendment No. 3 to Registration Statement on Form S-1 filed with the SEC on January 7, 2021 (the “Form S-1”) and (2) Project Barolo Merger Sub, Inc., a Delaware corporation and wholly owned
subsidiary of the Company that was incorporated on January 6, 2022. 

  
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 (ii) Authorization; Enforcement; Validity. (i) The Company has the requisite
corporate power and authority to enter into and subsequent to the Merger (and subject to stockholder approval to the extent of issuances in excess of the Exchange Cap) perform its obligations under this Agreement and each of the other Transaction
Documents, and to issue the Securities in accordance with the terms hereof and thereof, (ii) the execution and delivery of the Transaction Documents by the Company and the consummation by it of the transactions contemplated hereby and thereby,
including without limitation, the issuance of the Commitment Shares (as defined below in Section 5(e)) and the reservation for issuance and the issuance of the Purchase Shares issuable under this Agreement, have been duly
authorized by the Company’s Board of Directors and other than the Merger, no further consent or authorization is required by the Company, its Board of Directors or its stockholders (except as provided in this Agreement), (iii) each of this
Agreement and the Registration Rights Agreement has been, and each other Transaction Document shall be on the Commencement Date, duly executed and delivered by the Company and (iv) this Agreement constitutes, and each other Transaction Document
upon its execution on behalf of the Company, shall constitute, the valid and binding obligations of the Company enforceable against the Company in accordance with their terms, except as such enforceability may be limited by bankruptcy, insolvency
(including, without limitation, all laws relating to fraudulent transfers), reorganization, moratorium or similar laws affecting enforcement of creditors’ rights generally and except as enforcement thereof is subject to general principles of
equity, including principles of commercial reasonableness, good faith and fair dealing (regardless of whether enforcement is considered in a proceeding in equity or at law) (“Enforceability Exceptions”). The Board of Directors of the
Company has approved the resolutions (the “Signing Resolutions”) substantially in the form as set forth as Exhibit C attached hereto to authorize this Agreement and the transactions contemplated hereby. The Signing Resolutions are
valid, in full force and effect and have not been modified or supplemented in any respect. The Company has delivered to the Investor a true and correct copy of a unanimous written consent adopting the Signing Resolutions executed by all of the
members of the Board of Directors of the Company or minutes of a meeting of the Board of Directors of the Company approving the Signing Resolutions. Except as set forth in this Agreement and the consummation of the Merger, no other approvals or
consents of the Company’s Board of Directors, any authorized committee thereof, or stockholders is necessary (except as provided in this Agreement) under applicable laws and the Certificate of Incorporation or Bylaws to authorize the execution
and delivery of this Agreement or any of the transactions contemplated hereby, including, but not limited to, the issuance of the Commitment Shares and the issuance of the Purchase Shares. 

(iii) Capitalization. As of the date hereof, the authorized and issued capital stock of the Company is set forth in the Company’s
Registration Statement on the Form S-1. Except as disclosed in the SEC Documents (as defined below), (i) no shares of the Company’s capital stock are subject to preemptive rights or any other similar
rights or any liens or encumbrances suffered by the Company, (ii) there are no outstanding debt securities, (iii) there are no outstanding options, warrants, scrip, rights to subscribe to, calls or commitments of any character whatsoever
relating to, or securities or rights convertible into, any shares of capital stock of the Company or any of its Subsidiaries, or contracts, commitments, understandings or arrangements by which the Company or any of its Subsidiaries is or may become
bound to issue additional shares of capital stock of the Company or any of its Subsidiaries or options, warrants, scrip, rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities or rights convertible into,
any shares of capital stock of the Company or any of its Subsidiaries, (iv) there are no agreements or arrangements under which the Company or any of its Subsidiaries is obligated to register the sale of any of their securities under the
Securities Act (except the Registration Rights Agreement), (v) there are no outstanding securities or instruments of the Company or any of its Subsidiaries which contain any redemption or similar provisions, and there are no contracts, commitments,
understandings or arrangements by which the Company or any of its Subsidiaries is or may become bound to redeem a security of the Company or any of its Subsidiaries, (vi) there are no securities or instruments containing anti-dilution or
similar provisions that will be triggered by the issuance of the Securities as described in this Agreement and (vii) the Company does not have any stock appreciation rights or “phantom stock” plans or agreements or any similar plan or
agreement. The Company has made available (provided that any documents filed with the SEC and available on the SEC’s EDGAR system shall be deemed to have been made available) to the Investor true and correct of the Company’s Certificate of
Incorporation, and the Bylaws, as amended 

  
 13 

 
and as in effect on the date hereof (the “Certificate of Incorporation”), and the Company’s Bylaws, as amended and as in effect on the date hereof (the
“Bylaws”), and summaries of the material terms of all securities convertible into or exercisable for Common Stock, if any, and copies of any documents containing the material rights of the holders thereof in respect thereto that, in
either case, are not disclosed in the Form S-1. 
 (iv) Issuance of Securities. Upon
consummation of the Merger, an aggregate of 17,316,667 shares of Common Stock (subject to equitable adjustment for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or
other similar transaction) will be duly authorized and reserved for issuance under this Agreement as Purchase Shares (upon purchase) and Commitment Shares (as defined below in Section 5(e)). Upon consummation of the Merger,
and upon issuance and payment therefor in accordance with the terms and conditions of this Agreement, the Purchase Shares shall be validly issued, fully paid and nonassessable and free from all taxes, liens, charges, restrictions, rights of first
refusal and preemptive rights with respect to the issue thereof, with the holders being entitled to all rights accorded to a holder of Common Stock. When issued in accordance with this Agreement, the Commitment Shares shall be validly issued, fully
paid and nonassessable and free from all taxes, liens, charges, restrictions, rights of first refusal and preemptive rights with respect to the issue thereof, with the holders being entitled to all rights accorded to a holder of Common Stock. The
resale of the Securities will be registered by the Company pursuant to the Securities Act upon the effectiveness of the Registration Statement. Upon receipt of the Purchase Shares and the Commitment Shares, the Investor will have good and marketable
title to such Securities and such Securities will be freely tradable on the Principal Market by any holder who is not an “affiliate” under the Act upon the effectiveness of the Registration Statement. 

(v) No Conflicts. The execution, delivery and performance of the Transaction Documents by the Company, the consummation of the Merger,
and the consummation by the Company of the transactions contemplated hereby and thereby (including, without limitation, the reservation for issuance and issuance of the Purchase Shares and the Commitment Shares) will not (i) result in a
violation of the Certificate of Incorporation, any Certificate of Designations, Preferences and Rights of any outstanding series of preferred stock of the Company or the Bylaws or (ii) conflict with, or constitute a default (or an event which
with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which the Company or any of its Subsidiaries is a
party, or result in a violation of any law, rule, regulation, order, judgment or decree (including federal and state securities laws and regulations and the rules and regulations of the Principal Market applicable to the Company or any of its
Subsidiaries) or by which any property or asset of the Company or any of its Subsidiaries is bound or affected, except in the case of conflicts, defaults, terminations, amendments, accelerations, cancellations and violations under clause (ii), which
could not reasonably be expected to result in a Company Material Adverse Effect. Neither the Company nor any of its Subsidiaries is in violation of any term of or is in default under any material contract, agreement, mortgage, indebtedness,
indenture, instrument, judgment, decree or order or any statute, rule or regulation applicable to the Company or its Subsidiaries, except for possible conflicts, defaults, terminations or amendments that could not reasonably be expected to have a
Company Material Adverse Effect or to result in any conflict related to the Merger. The business of the Company and its Subsidiaries is not being conducted, and shall not be conducted, in violation of any law, ordinance, or regulation of any
governmental entity, except for possible violations, the sanctions for, or consequences of, which either individually or in the aggregate could not reasonably be expected to have a Company Material Adverse Effect. Except as specifically contemplated
by this Agreement, the Registration Rights Agreement and any consents related to the Merger, and as required under the Securities Act or the Exchange Act or applicable state securities laws and the rules and regulations of the Principal Market, the
Company is not required to obtain any consent, authorization or order of, or make any filing or registration with, any court or governmental agency or any regulatory or self-regulatory agency in order for it to execute, deliver or

  
 14 

 
perform any of its obligations under or contemplated by the Transaction Documents in accordance with the terms hereof or thereof. Except as set forth or contemplated elsewhere in this Agreement
or the Registration Rights Agreement (including with respect to the receipt of stockholder approval for any issuances in excess of the Excess Cap), all consents, authorizations, orders, filings and registrations which the Company is required to
obtain pursuant to the preceding sentence shall be obtained or effected on or prior to the Commencement Date. Except as disclosed in the SEC Documents, since one year prior to the date hereof, the Company has not received nor delivered any notices
or correspondence from or to the Principal Market, other than notices with respect to listing of additional shares of Common Stock and other routine correspondence. To the Company’s knowledge, the Principal Market has not commenced any
delisting proceedings against the Company. 
 (vi) SEC Documents; Financial Statements. Upon consummation of the Merger, the Company
shall have filed all reports, schedules, forms, statements and other documents required to be filed by the Company under the Securities Act and the Exchange Act, including pursuant to Section 13(a) or 15(d) thereof for such period as the
Company was required by law or regulation to file such material (the foregoing materials, including the exhibits thereto and documents incorporated by reference therein, being collectively referred to herein as the “SEC Documents”).
As of their respective dates, the SEC Documents complied in all material respects with the requirements of the Securities Act and the Exchange Act, as applicable. None of the SEC Documents, 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, in the light of the circumstances under which they were made, not misleading. The financial statements of the Company
included in the SEC Documents comply in all material respects with applicable accounting requirements and the rules and regulations of the SEC with respect thereto as in effect at the time of filing. Such financial statements have been prepared in
accordance with United States generally accepted accounting principles applied on a consistent basis during the periods involved (“GAAP”), except as may be otherwise specified in such financial statements or the notes thereto and
except that unaudited financial statements may not contain all footnotes required by GAAP, and fairly present in all material respects the financial position of the Company and its consolidated Subsidiaries 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, immaterial, year-end audit adjustments. Except as set forth in the SEC Documents, the
Company has received no notices or correspondence from the SEC for the one year preceding the date hereof. The SEC has not commenced any enforcement proceedings against the Company or any of its Subsidiaries. 

(vii) Acknowledgment Regarding Investor’s Status. The Company acknowledges and agrees that the Investor is acting solely in
the capacity of arm’s length purchaser with respect to the Transaction Documents and the transactions contemplated hereby and thereby. The Company further acknowledges that the Investor is not acting as a financial advisor or fiduciary of the
Company (or in any similar capacity) with respect to the Transaction Documents and the transactions contemplated hereby and thereby and any advice given by the Investor or any of its representatives or agents in connection with the Transaction
Documents and the transactions contemplated hereby and thereby is merely incidental to the Investor’s purchase of the Securities. The Company further represents to the Investor that the Company’s decision to enter into the Transaction
Documents has been based solely on the independent evaluation by the Company and its representatives and advisors. 
 (viii) No General
Solicitation; No Aggregated or Integrated Offering. Neither the Company, nor any of its affiliates that it controls, nor any Person acting on its or their behalf, has engaged in any form of general solicitation or general advertising (within the
meaning of Regulation D under the Securities Act) in connection with the offer or sale of the Securities. Neither the Company, nor or any of its affiliates that it controls, nor any Person acting on their behalf has, directly or indirectly, made any
offers or sales of any security or solicited any offers to purchase any security, under circumstances that would 

  
 15 

 
require registration of the offer and sale of any of the Securities under the Securities Act, whether through aggregation or integration with prior offerings or otherwise, or cause this offering
of the Securities to be aggregated or integrated with prior offerings by the Company in a manner that would require stockholder approval pursuant to the rules of the Principal Market on which any of the securities of the Company are listed or
designated. The issuance and sale of the Securities hereunder, as of the date of this Agreement, does not contravene the rules and regulations of the Principal Market. 

(ix) Application of Takeover Protections. The Company and its Board of Directors have taken or will take prior to the Commencement Date
all necessary action, if any, in order to render inapplicable any control share acquisition, business combination, poison pill (including any distribution under a rights agreement) or other similar anti-takeover provision under the Certificate of
Incorporation or the laws of the state of its incorporation which is or could become applicable to the Investor as a result of the transactions contemplated by this Agreement, including, without limitation, the Company’s issuance of the
Securities and the Investor’s ownership of the Securities. 
 (x) Disclosure. Except with respect to the material terms and
conditions of the transactions contemplated by the Transaction Documents that will be timely publicly disclosed by the Company, the Company confirms that neither it nor any other Person acting on its behalf has provided the Investor or its agents or
counsel with any information that it believes constitutes or might constitute material, non-public information which is not otherwise disclosed in the Registration Statement or the SEC Documents. The Company
understands and confirms that the Investor will rely on the foregoing representation in effecting purchases and sales of securities of the Company. All of the disclosure furnished by or on behalf of the Company to the Investor regarding the Company,
its business and the transactions contemplated hereby is true and correct in all material respects and does not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements made
therein, in light of the circumstances under which they were made, not misleading. The press releases disseminated by the Company during the twelve months preceding the date of this Agreement, together with the Company’s SEC Documents, taken as
a whole do not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made and when
made, not misleading. The Company acknowledges and agrees that the Investor neither makes nor has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in Section 3
hereof. 
 (xi) DTC Eligibility. Subsequent to the Merger, the Company, through the Transfer Agent, shall participate in the DTC Fast
Automated Securities Transfer (FAST) Program and the Common Stock can be transferred electronically to third parties via the DTC Fast Automated Securities Transfer (FAST) Program. 

(xii) Sarbanes-Oxley. The Company is in compliance with all material provisions of the Sarbanes-Oxley Act of 2002, as amended, which
are applicable to it as of the date hereof. 
 (xiii) Certain Fees. No brokerage or finder’s fees or commissions are or will be
payable by the Company to any broker, financial advisor or consultant, finder, placement agent, investment banker, bank or other Person with respect to the transactions contemplated by the Transaction Documents. The Investor shall have no obligation
with respect to any fees or with respect to any claims made by or on behalf of other Persons for fees of a type contemplated in this Section 4(a)(xiii) that may be due in connection with the transactions contemplated by the Transaction
Documents. 

  
 16 

 (xiv) Investment Company. The Company is not, and immediately after receipt of
payment for the Securities will not be, an “investment company” within the meaning of the Investment Company Act of 1940, as amended. 

(xv) Listing and Maintenance Requirements. The Common Stock is registered pursuant to Section 12(b) or 12(g) of the Exchange Act,
and the Company has taken no action designed to, or which to its knowledge is likely to have the effect of, terminating the registration of the Common Stock pursuant to the Exchange Act nor has the Company received any notification that the SEC is
currently contemplating terminating such registration. The Company has not, in the twelve (12) months preceding the date hereof, received any notice from any Person to the effect that the Company is not in compliance with the listing or
maintenance requirements of the Principal Market. The Company is in compliance in all material respects with all such listing and maintenance requirements. 

(xvi) No Market Manipulation. The Company has not, and to its knowledge no Person acting on its behalf has, (i) taken, directly or
indirectly, any action designed to cause or to result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of any of the Securities, (ii) sold, bid for, purchased, or, paid any
compensation for soliciting purchases of, any of the Securities, or (iii) paid or agreed to pay to any Person any compensation for soliciting another to purchase any other securities of the Company. 

(xvii) No Disqualification Events. None of the Company, any of its predecessors, any affiliated issuer, any director, executive
officer, other officer of the Company participating in the offering contemplated hereby, any beneficial owner of 20% or more of the Company’s outstanding voting equity securities, calculated on the basis of voting power, nor any promoter (as
that term is defined in Rule 405 under the Securities Act) connected with the Company in any capacity at the time of sale (each, an “Issuer Covered Person”) is subject to any of the “Bad Actor” disqualifications described
in Rule 506(d)(1)(i) to (viii) under the Securities Act (a “Disqualification Event”), except for a Disqualification Event covered by Rule 506(d)(2) or (d)(3) under the Securities Act. The Company has exercised reasonable care
to determine whether any Issuer Covered Person is subject to a Disqualification Event. 
 (b) Apexigen Representations and
Warranties. Apexigen represents and warrants to the Investor that, except as set forth in the disclosure schedules attached hereto, which exceptions shall be deemed to be a part of the representations and warranties made hereunder, as of the
date hereof and as of the Commencement Date: 
 (i) Organization and Qualification. Apexigen is an entity duly incorporated or
otherwise organized, validly existing and in good standing under the laws of the jurisdiction of its incorporation or organization, with the requisite corporate power and authority to own and use its properties and assets and to carry on its
business as currently conducted. Apexigen is not in violation or default of any of the provisions of its certificate of incorporation or bylaws. Apexigen is duly qualified to conduct business and is in good standing as a foreign corporation or other
entity in each jurisdiction in which the nature of the business conducted or property owned by it makes such qualification necessary, except where the failure to be so qualified or in good standing, as the case may be, could not reasonably be
expected to result in an Apexigen Material Adverse Effect and no proceeding has been instituted in any such jurisdiction revoking, limiting or curtailing or seeking to revoke, limit or curtail such power and authority or qualification. Apexigen has
no Subsidiaries. 
 (ii) Authorization; Enforcement; Validity. (i) Apexigen has the requisite corporate power and authority to
enter into and perform its obligations under this Agreement, the Registration Rights Agreement and each of the other Transaction Documents, (ii) the execution and delivery of the Transaction Documents by Apexigen and the consummation by it of
the transactions contemplated hereby and thereby 

  
 17 

 
have been duly authorized by Apexigen’s Board of Directors and no further consent or authorization is required by Apexigen, its Board of Directors or its stockholders (except as provided in
this Agreement), (iii) each of this Agreement and the Registration Rights Agreement has been, and each other Transaction Document shall be on the Commencement Date, duly executed and delivered by Apexigen and (iv) each of this Agreement and the
Registration Rights Agreement constitutes, and each other Transaction Document upon its execution on behalf of Apexigen, shall constitute, the valid and binding obligations of Apexigen enforceable against Apexigen in accordance with their terms,
except as such enforceability may be limited by general principles of equity or applicable bankruptcy, insolvency, reorganization, moratorium, liquidation or similar laws relating to, or affecting generally, the enforcement of creditors’ rights
and remedies. The Board of Directors of Apexigen has approved resolutions (the “Apexigen Signing Resolutions”) that authorize this Agreement, the Registration Rights Agreement and the transactions contemplated hereby. The Apexigen
Signing Resolutions are valid, in full force and effect and have not been modified or supplemented in any respect. Apexigen has delivered to the Investor a true and correct copy of minutes of a meeting of the Board of Directors of Apexigen at which
the Apexigen Signing Resolutions were duly adopted by the Board of Directors or a unanimous written consent adopting the Apexigen Signing Resolutions executed by all of the members of the Board of Directors of Apexigen. Except as set forth in this
Agreement, no other approvals or consents of Apexigen’s Board of Directors, any authorized committee thereof, or stockholders (except as provided in this Agreement) is necessary under applicable laws and Apexigen’s certificate of
incorporation and bylaws to authorize the execution and delivery of the Transaction Documents or any of the transactions contemplated thereby. 

(iii) No Conflicts. The execution, delivery and performance of the Transaction Documents by Apexigen and the consummation by Apexigen
of the transactions contemplated hereby and thereby will not (i) result in a violation of Apexigen’s certificate of incorporation or bylaws or (ii) conflict with, or constitute a default (or an event which with notice or lapse of time
or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which Apexigen is a party, or result in a violation of any law, rule,
regulation, order, judgment or decree (including federal and state securities laws and regulations applicable to Apexigen) or by which any property or asset of Apexigen is bound or affected, except in the case of conflicts, defaults, terminations,
amendments, accelerations, cancellations and violations under clause (ii), which could not reasonably be expected to result in an Apexigen Material Adverse Effect. Apexigen is not in violation of any term of or in default under its certificate of
incorporation or bylaws. Apexigen is not in violation of any term of or is in default under any material contract, agreement, mortgage, indebtedness, indenture, instrument, judgment, decree or order or any statute, rule or regulation applicable to
Apexigen, except for possible conflicts, defaults, terminations or amendments that could not reasonably be expected to have an Apexigen Material Adverse Effect. The business of Apexigen is not being conducted, and shall not be conducted, in
violation of any law, ordinance or regulation of any governmental entity, except for possible violations, the sanctions for which either individually or in the aggregate could not reasonably be expected to have an Apexigen Material Adverse Effect.
Except as specifically contemplated by this Agreement and as required under the Securities Act or applicable state securities laws, Apexigen is not required to obtain any consent, authorization or order of, or make any filing or registration with,
any court or governmental agency or any regulatory or self-regulatory agency in order for it to execute, deliver or perform any of its obligations under or contemplated by the Transaction Documents in accordance with the terms hereof or thereof.
Except as set forth elsewhere in this Agreement, all consents, authorizations, orders, filings and registrations which Apexigen is required to obtain pursuant to the preceding sentence shall be obtained or effected on or prior to the Commencement
Date. 
 (iv) Absence of Certain Changes. Except as disclosed in the SEC Documents, since December 31, 2021, there has been no
material adverse change in the business, properties, operations, financial condition or results of operations of the Apexigen. Apexigen has not taken any steps, and does not currently expect to take any steps, to seek protection pursuant to any
Bankruptcy Law nor does Apexigen have any knowledge or reason to believe that its creditors intend to initiate involuntary bankruptcy or insolvency proceedings. Apexigen is financially solvent and is generally able to pay its debts as they
become due. 

  
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 (v) Absence of Litigation. There is no action, suit, proceeding, inquiry or, to
Apexigen’s knowledge, investigation before or by any court, public board, government agency, self-regulatory organization or body pending or, to the knowledge of Apexigen, threatened against or affecting Apexigen, or any of Apexigen’s
officers or directors in their capacities as such, which could reasonably be expected to have an Apexigen Material Adverse Effect. 
 (vi)
Acknowledgment Regarding Investor’s Status. Apexigen acknowledges and agrees that the Investor is acting solely in the capacity of arm’s length purchaser with respect to the Transaction Documents and the transactions contemplated
hereby and thereby. Apexigen further acknowledges that the Investor is not acting as a financial advisor or fiduciary of Apexigen (or in any similar capacity) with respect to the Transaction Documents and the transactions contemplated hereby and
thereby and any advice given by the Investor or any of its representatives or agents in connection with the Transaction Documents and the transactions contemplated hereby and thereby is merely incidental to the Investor’s purchase of the
Securities. Apexigen further represents to the Investor that Apexigen’s decision to enter into the Transaction Documents has been based solely on the independent evaluation by Apexigen and its representatives and advisors. 

(vii) No General Solicitation. Neither Apexigen, nor any of its affiliates, nor any Person acting on its or their behalf, has engaged
in any form of general solicitation or general advertising (within the meaning of Regulation D under the Securities Act) in connection with the offer or sale of the Securities. 

(viii) Intellectual Property Rights. Apexigen owns or possesses or can obtain on commercially reasonable terms adequate rights or
licenses to use all trademarks, trade names, service marks, service mark registrations, service names, patents, patent rights, copyrights, inventions, licenses, approvals, governmental authorizations, trade secrets and other intellectual property
rights necessary to conduct its business as now conducted. None of Apexigen’s rights in its owned and material trademarks, trade names, service marks, service mark registrations, service names, patents, patent rights, copyrights, trade secrets
or other intellectual property rights have expired or terminated, or, by the terms and conditions thereof, could expire or terminate within two years from the date of this Agreement. Apexigen does not have any knowledge of any infringement by
Apexigen of any trademark, trade name rights, patents, patent rights, copyrights, service names, service marks, service mark registrations, trade secret or other intellectual property rights of others, and there is no claim, action or proceeding
being made or brought against, or to Apexigen’s knowledge, being threatened against, Apexigen regarding trademark, trade name, patents, patent rights, copyright, service names, service marks, service mark registrations, trade secret or other
infringement, which could reasonably be expected to have an Apexigen Material Adverse Effect. 
 (ix) Environmental Laws. Apexigen
(i) is in compliance with any and all applicable foreign, federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or
contaminants (“Environmental Laws”), (ii) has received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct its businesses and (iii) is in compliance with all terms and
conditions of any such permit, license or approval, except where, in each of the three foregoing clauses, the failure to so comply could not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect. 

  
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 (x) Title. Apexigen has good and marketable title in fee simple to all real property
owned by it and good and marketable title in all tangible personal property owned by it that is material to its business, in each case free and clear of all liens, encumbrances and defects (“Liens”) and, except for Liens as do not
materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by Apexigen and Liens for the payment of federal, state or other taxes, the payment of which is neither
delinquent nor subject to penalties. Any real property and facilities held under lease by Apexigen are held by them under valid, subsisting and enforceable leases with which Apexigen is in compliance with such exceptions as are not material and do
not interfere with the use made and proposed to be made of such property and buildings by Apexigen. 
 (xi) Insurance. Apexigen is
insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as management of Apexigen believes to be prudent and customary in the businesses in which Apexigen is engaged. Apexigen has not been refused
any insurance coverage sought or applied for and Apexigen has no reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be
necessary to continue its business at a cost that would not materially and adversely affect the condition, financial or otherwise, or the earnings, business or operations of Apexigen. 

(xii) Regulatory Permits. Apexigen possesses all material certificates, authorizations and permits issued by the appropriate federal,
state or foreign regulatory authorities necessary to conduct its business, and Apexigen has not received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit. 

(xiii) Tax Status. Apexigen has made or filed all federal and state income and all other material tax returns, reports and declarations
required by any jurisdiction to which it is subject and has paid all taxes and other governmental assessments and charges that are material in amount, shown or determined to be due on such returns, reports and declarations, except those being
contested in good faith (but only to the extent that Apexigen has set aside on its books provisions reasonably adequate for the payment of all unpaid and unreported taxes) and has set aside on its books provision reasonably adequate for the payment
of all taxes for periods subsequent to the periods to which such returns, reports or declarations apply. There are no unpaid taxes in any material amount claimed in writing to be due by the taxing authority of any jurisdiction, and to the knowledge
of Apexigen there is no basis for any such claim. 
 (xiv) Transactions With Affiliates. None of the officers or directors of
Apexigen and, to the knowledge of Apexigen, none of the employees of Apexigen is presently a party to any transaction with Apexigen (other than for services as employees, officers and directors), including any contract, agreement or other
arrangement providing for the furnishing of services to or by, providing for rental of real or personal property to or from, or otherwise requiring payments to or from any officer, director or such employee or, to the knowledge of Apexigen, any
entity in which any officer, director, or any such employee has a substantial interest or is an officer, director, trustee or partner, in each case in excess of $120,000 other than for (i) payment of salary or consulting fees for services
rendered, (ii) reimbursement for expenses incurred on behalf of Apexigen and (iii) other employee benefits, including stock option agreements under any stock option plan of Apexigen. 

(xv) Disclosure. Except with respect to the material terms and conditions of the transactions contemplated by the Transaction Documents
that will be timely publicly disclosed by Apexigen, Apexigen confirms that neither it nor any other Person acting on its behalf has provided the Investor or its agents or counsel with any information that it believes constitutes or might constitute
material, non-public information which is not otherwise disclosed in the Registration Statement or the SEC Documents. Apexigen understands and confirms that the Investor will rely on the foregoing
representation in effecting purchases and sales of the Securities. All of the disclosure furnished by or on behalf of Apexigen to the Investor regarding Apexigen, its business and the transactions contemplated hereby is true and correct and does not
contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements made therein, in light of the circumstances under which they were made, not misleading. Apexigen acknowledges and
agrees that the Investor neither makes nor has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in Section 3 hereof. 

  
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 (xvi) Foreign Corrupt Practices. Since January 1, 2018, neither Apexigen,
nor to the knowledge of Apexigen, any agent or other Person acting on behalf of Apexigen, has (i) directly or indirectly, used any funds for unlawful contributions, gifts, entertainment or other unlawful expenses related to foreign or domestic
political activity, (ii) made any unlawful payment to foreign or domestic government officials or employees or to any foreign or domestic political parties or campaigns from corporate funds, (iii) failed to disclose fully any contribution
made by Apexigen (or made by any Person acting on its behalf of which Apexigen is aware) which is in violation of applicable anti-bribery/anti-corruption laws, or (iv) violated in any material respect any provision of the Foreign Corrupt
Practices Act of 1977, as amended. 
 (xvii) Certain Fees. No brokerage or finder’s fees or commissions are or will be payable
by Apexigen to any broker, financial advisor or consultant, finder, placement agent, investment banker, bank or other Person with respect to the transactions contemplated by the Transaction Documents. The Investor shall have no obligation with
respect to any fees or with respect to any claims made by or on behalf of other Persons for fees of a type contemplated in this Section 4(b)(xvii) that may be due in connection with the transactions contemplated by the
Transaction Documents. 
 (xviii) Accountants. Apexigen’s accountants are set forth in the SEC Documents and, to the knowledge
of Apexigen, such accountants are an independent registered public accounting firm as required by the Securities Act. 
 (xix) No Market
Manipulation. Apexigen has not, and to its knowledge no Person acting on its behalf has, (i) taken, directly or indirectly, any action designed to cause or to result in the stabilization or manipulation of the price of any security of
the Company to facilitate the sale or resale of any of the Securities, (ii) sold, bid for, purchased, or, paid any compensation for soliciting purchases of, any of the Securities, or (iii) paid or agreed to pay to any Person any
compensation for soliciting another to purchase any other securities of the Company. 
 (xx) No Disqualification Events. None of
Apexigen, any of its predecessors, any affiliated issuer, any director, executive officer, other officer of Apexigen participating in the offering contemplated hereby, any beneficial owner of 20% or more of Apexigen’s outstanding voting equity
securities, calculated on the basis of voting power, nor any promoter (as that term is defined in Rule 405 under the Securities Act) connected with Apexigen in any capacity at the time of sale (each, a “Apexigen Issuer Covered
Person”) is subject to any of the “Bad Actor” disqualifications described in Rule 506(d)(1)(i) to (viii) under the Securities Act (a “Disqualification Event”), except for a Disqualification Event covered by
Rule 506(d)(2) or (d)(3) under the Securities Act. Apexigen has exercised reasonable care to determine whether any Apexigen Issuer Covered Person is subject to a Disqualification Event. 

 

	5.	 COVENANTS. 

(a) Filing of Current Report and Registration Statement. Each of the Company and Apexigen agrees that the Company shall, within the time
required under the Exchange Act, file with the SEC a report on Form 8-K relating to the transactions contemplated by, and describing the material terms and conditions of, the Transaction Documents (the
“Current Report”). The Company shall also file with the SEC, within thirty (30) days of the date of closing of the Merger, a new registration statement (as amended or supplemented or replaced with a New Registration Statement,
the “Registration Statement”) covering the 

  
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resale of the Purchase Shares and all of the Commitment Shares in accordance with the terms of the Registration Rights Agreement between the Company and the Investor, dated as of the date hereof
(the “Registration Rights Agreement”), provided, however, that the Company may delay filing or suspend the use of any Registration Statement if the Company determines, upon advice of legal counsel, that in order for the registration
statement to not contain a material misstatement or omission, an amendment thereto would be needed, or if the Company’s Board of Directors, upon advice of legal counsel, reasonably believes that such filing or use could materially affect a bona
fide business or financing transaction of the Company or would require premature disclosure of information that could materially adversely affect the Company. The Company shall permit the Investor to review and comment upon the final pre-filing draft version of the Current Report at least two (2) Business Days prior to its filing with the SEC and, with respect to information regarding the Investor or the transaction contemplated hereby, the
Company shall not file the Current Report or the Registration Statement with the SEC in a form to which the Investor reasonably objects. The Investor shall use its reasonable best efforts to comment upon the final
pre-filing draft version of the Current Report within one (1) Business Day from the date the Investor receives it from the Company. 

(b) Blue Sky. The Company shall take all such action, if any, as is reasonably necessary in order to obtain an exemption for or to
register or qualify (i) the issuance of the Commitment Shares and the sale of the Purchase Shares to the Investor under this Agreement and (ii) any subsequent resale of all Commitment Shares and all Purchase Shares by the Investor, in each
case, under applicable securities or “Blue Sky” laws of the states of the United States in such states as is reasonably requested by the Investor from time to time, and shall provide evidence of any such action so taken to the Investor
provided, however, that the Company shall not be obligated to file any general consent to service of process or to qualify as a foreign corporation or as a dealer in securities in any jurisdiction in which it is not so qualified or to subject itself
to taxation in respect of doing business in any jurisdiction in which it is not otherwise so subject”. 
 (c) Listing/DTC. The
Company shall use its commercially reasonable efforts to promptly secure the listing of all of the Purchase Shares and Commitment Shares to be issued to the Investor hereunder on the Principal Market (subject to official notice of issuance) and upon
each other national securities exchange or automated quotation system, if any, upon which the Common Stock is then listed, and shall use commercially reasonable efforts to maintain, so long as any shares of Common Stock shall be so listed, such
listing of all such Securities from time to time issuable hereunder. The Company shall use commercially reasonable efforts to maintain the listing of the Common Stock on the Principal Market and shall comply in all respects with the Company’s
reporting, filing and other obligations under the bylaws or rules and regulations of the Principal Market. The Company shall not take any action that would reasonably be expected to result in the delisting or suspension of the Common Stock on the
Principal Market. The Company shall promptly, and in no event later than the following Business Day, provide to the Investor copies of any notices it receives from any Person regarding the continued eligibility of the Common Stock for listing on the
Principal Market; provided, however, that the Company shall not be required to provide the Investor copies of any such notice that the Company reasonably believes constitutes material non-public information
and the Company would not be required to publicly disclose such notice in any report or statement filed with the SEC and under the Exchange Act or the Securities Act. The Company shall pay all fees and expenses in connection with satisfying its
obligations under this Section 5(c). The Company shall use its commercially reasonable efforts to ensure that its Common Stock can be transferred electronically as DWAC Shares. 

(d) Prohibition of Short Sales and Hedging Transactions. The Investor agrees that beginning on the date of this Agreement and ending on
the date of termination of this Agreement as provided in Section 11, the Investor and its agents, representatives and affiliates shall not in any manner whatsoever enter into or effect, directly or indirectly, any (i)
“short sale” (as such term is defined in Rule 200 of Regulation SHO of the Exchange Act) of the Common Stock or (ii) hedging transaction, which establishes a net short position with respect to the Common Stock. 

  
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 (e) Issuance of Commitment Shares. In consideration for the Investor’s execution
and delivery of this Agreement, the Company shall cause the Transfer Agent to issue shares of Common Stock (the “Initial Commitment Shares”) directly to the Investor on the date of closing of the Merger, and shall deliver to the
Transfer Agent on the date of this Agreement the Irrevocable Transfer Agent Instructions in the form as set forth in Section 6. The Company shall cause the Commitment Shares to be issued to the Investor as follows:
(i) on the date of closing of the Merger, 150,000 shares of Common Stock shall be delivered to the Investor and (ii) on the date that is ninety (90) calendar days after the date of closing of the Merger (the “Additional
Commitment Share Delivery Date”), $1,500,000 of shares of Common Stock (the “Additional Commitment Shares” and, together with the Initial Commitment Shares, the “Commitment Shares”) shall be delivered to
the Investor. The price per share of the Additional Commitment shares shall be equal to the arithmetic average of the Closing Sale Price for the Common Stock during the ten (10) consecutive Business Days ending on the Business Day immediately
preceding the Additional Commitment Share Delivery Date. In no event shall the amount of the Additional Commitment Shares to be issued under this Agreement exceed 500,000 shares of Common Stock. For the avoidance of doubt, all of the Commitment
Shares shall be fully earned as of the date of this Agreement, irrespective of any subsequent termination of this Agreement. 
 (f) Due
Diligence; Non-Public Information. The Investor shall have the right, from time to time as the Investor may reasonably deem appropriate and upon reasonable advance notice to the Company and Apexigen, to
perform reasonable due diligence on the Company and Apexigen during normal business hours. Each of the Company and Apexigen and their respective officers and employees shall provide information and reasonably cooperate with the Investor in
connection with any reasonable request by the Investor related to the Investor’s due diligence of the Company and Apexigen. Each party hereto agrees not to disclose any Confidential Information of the other party to any third party and shall
not use the Confidential Information for any purpose other than in connection with, or in furtherance of, the transactions contemplated hereby. Each party hereto acknowledges that the Confidential Information shall remain the property of the
disclosing party and agrees that it shall take all reasonable measures to protect the secrecy of any Confidential Information disclosed by the other party. Each of the Company and Apexigen confirms that neither it nor any other Person acting on its
behalf shall provide the Investor or its agents or counsel with any information that constitutes or might constitute material, non-public information, unless a simultaneous public announcement thereof is made
by the Company in the manner contemplated by Regulation FD. In the event of a breach of the foregoing covenant by the Company, Apexigen or any Person acting on their behalf (as determined in the reasonable good faith judgment of the Investor), in
addition to any other remedy provided herein or in the other Transaction Documents, if the Investor is holding any Securities at the time of the disclosure of material, non-public information, the Investor
shall have the right to make a public disclosure, in the form of a press release, public advertisement or otherwise, of such material, non-public information without the prior approval by the Company and
Apexigen; provided the Investor shall have first provided notice to the Company and Apexigen that it believes it has received information that constitutes material, non-public information, the Company and
Apexigen shall have at least two (2) Business Days to either (i) demonstrate that such information is not material non-public information to the satisfaction of the Investor or (ii) publicly
disclose such material, non-public information prior to any such disclosure by the Investor, and the Company and Apexigen shall have failed to demonstrate to the Investor in writing within such time period
that such information does not constitute material, non-public information, and the Company and Apexigen shall have failed to publicly disclose such material, non-public
information within such time period. The Investor shall not have any liability to the Company, any of its Subsidiaries, Apexigen, or any of their respective directors, officers, employees, stockholders or agents, for any such disclosure. Each of the
Company and Apexigen understands and confirms that the Investor shall be relying on the foregoing covenants in effecting transactions in securities of the Company. 

  
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 (g) Purchase Records. The Investor and the Company shall each maintain records
showing the remaining Available Amount at any given time and the dates and Purchase Amounts for each Regular Purchase, Accelerated Purchase and Additional Accelerated Purchase or shall use such other method, reasonably satisfactory to the Investor
and the Company. 
 (h) Taxes. The Company shall pay any and all transfer, stamp or similar taxes that may be payable with respect to
the issuance and delivery of any shares of Common Stock to the Investor made under this Agreement. For the avoidance of doubt, any other taxes incurred by the Investor (including any taxes on income resulting from the transactions contemplated by
this Agreement)_ shall solely be the responsibility of the Investor. 
 (i) Aggregation. From and after the date of this
Agreement, neither the Company, nor or any of its affiliates will, and the Company shall use its reasonable best efforts to ensure that no Person acting on their behalf will, directly or indirectly, make any offers or sales of any security or
solicit any offers to purchase any security, under circumstances that would cause this offering of the Securities by the Company to the Investor to be aggregated with other offerings by the Company in a manner that would require stockholder approval
pursuant to the rules of the Principal Market on which any of the securities of the Company are listed or designated, unless stockholder approval is obtained before the closing of such subsequent transaction in accordance with the rules of such
Principal Market. 
 (j) Use of Proceeds. The Company will use the net proceeds from the offering for any corporate purpose at the
sole discretion of the Company. 
 (k) Other Transactions. During the term of this Agreement, neither Company nor Apexigen shall
enter into, announce or recommend to its stockholders any agreement, plan, arrangement or transaction in or of which the terms thereof would restrict, materially delay, conflict with or impair the ability or right of the Company to perform its
obligations under the Transaction Documents, including, without limitation, the obligation of the Company or Apexigen to deliver the Purchase Shares and the Commitment Shares to the Investor in accordance with the terms of the Transaction Documents.

 (l) Integration. From and after the date of this Agreement, neither the Company nor Apexigen, nor or any of their respective
affiliates will, and each of the Company and Apexigen shall use its reasonable best efforts to ensure that no Person acting on their behalf will, directly or indirectly, make any offers or sales of any security or solicit any offers to purchase any
security, under circumstances that would require registration of the offer and sale of any of the Securities under the Securities Act. 

(m) Limitation on Variable Rate Transactions. From and after the date of this Agreement until the twenty-four (24) month
anniversary of the Commencement Date (irrespective of any earlier termination of this Agreement), the Company shall be prohibited from effecting or entering into an agreement to effect any issuance by the Company or any of its Subsidiaries of Common
Stock involving a Variable Rate Transaction other than with the Investor. “Variable Rate Transaction” means an “equity line of credit” or substantially similar transaction whereby an investor is irrevocably bound to
purchase securities over a period of time from the Company at a price based on the market price of the Company’s Common Stock at the time of each such purchase, provided, however, that this Section 5(m) shall not be deemed to prohibit the
issuance and sale of Common Stock pursuant to an “at-the-market offering” by the Company exclusively through a registered broker-dealer acting as agent of the
Company pursuant to a written agreement between the Company and such registered broker-dealer. 

  
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	6.	 TRANSFER AGENT INSTRUCTIONS. 

(a) Initial Commitment Shares. Upon consummation of the Merger, the Company shall issue to the Transfer Agent (and any subsequent
transfer agent) irrevocable instructions, in substantially the form agreed to prior to the date hereof, to issue the Initial Commitment Shares in accordance with the terms of this Agreement (the “Irrevocable Initial Transfer Agent
Instructions”). The certificate or book-entry statement(s) representing the Initial Commitment Shares shall bear the following restrictive legend (the “Restrictive Legend”) and no other legend whatsoever: 

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE
SECURITIES LAWS. THE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
OR APPLICABLE STATE SECURITIES LAWS, UNLESS SOLD PURSUANT TO: (1) RULE 144 UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR (2) AN OPINION OF HOLDER’S COUNSEL, IN A CUSTOMARY FORM, THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR
APPLICABLE STATE SECURITIES LAWS. 
 The Company warrants to the Investor that, while the Agreement is effective, no instruction other than
the Irrevocable Initial Transfer Agent Instructions referred to in this Section 6 will be given by the Company to the Transfer Agent with respect to the Initial Commitment Shares, and the Initial Commitment Shares shall
otherwise be freely transferable on the books and records of the Company. 
 (b) Additional Commitment Shares. 90 calendar days
following the consummation of the Merger, the Company shall issue to the Transfer Agent (and any subsequent transfer agent) irrevocable instructions, in substantially the form agreed to prior to the date hereof, to issue the Additional Commitment
Shares in accordance with the terms of this Agreement (the “Irrevocable Additional Transfer Agent Instructions”). All Additional Commitment Shares to be issued to or for the benefit of the Investor pursuant to this Agreement shall be
issued as DWAC Shares. The Company warrants to the Investor that, while the Agreement is effective, no instruction other than the Irrevocable Additional Transfer Agent Instructions referred to in this Section 6 will be given by the Company to
the Transfer Agent with respect to the Additional Commitment Shares, and the Additional Commitment Shares shall otherwise be freely transferable on the books and records of the Company. Notwithstanding anything to the contrary in this
Section 6(b), to the extent the Additional Commitment Shares are issued prior to the effectiveness of the Registration Statement, the certificate or book-entry statement(s) representing the Additional Commitment Shares shall bear the same
restrictive legend as the Initial Commitment Shares and as referenced in Section 6(a) above. 
 (c) Purchase Shares. On the date
of the Commencement, the Company shall issue to the Transfer Agent, and any subsequent transfer agent, irrevocable instructions in the form agreed to prior to the date hereof (the “Commencement Irrevocable Transfer Agent
Instructions”) to issue the Purchase Shares in accordance with the terms of this Agreement and the Registration Rights Agreement. All Purchase Shares to be issued from and after Commencement to or for the benefit of the Investor pursuant to
this Agreement shall be issued only as DWAC Shares. The Company represents and warrants to the Investor that, while this Agreement is effective, no instruction other than as contemplated by the Commencement Irrevocable Transfer Agent Instructions
and any Notice of Effectiveness of Registration Statement (as defined in the Registration Rights Agreement) will be given by the Company to the Transfer Agent with respect to the Purchase Shares from and after Commencement, and no instruction or
other communication to the Transfer Agent with respect to the issuance of the Purchase Shares shall be made without the approval 

  
 25 

 
of the Investor. The Company shall provide confirmation of receipt by the Transfer Agent of all instructions pursuant to the Commencement Irrevocable Transfer Agent Instructions with respect to
Purchase Shares within one Business Day of delivery of any Purchase Notice. The Purchase Shares covered by the Registration Statement shall otherwise be freely transferable on the books and records of the Company. 

 

	7.	 CONDITIONS TO THE COMPANY’S RIGHT TO COMMENCE SALES OF SHARES OF COMMON STOCK.

 The right of the Company hereunder to commence sales of the Purchase Shares as of the Commencement Date is subject
to the satisfaction of each of the following conditions: 
 (a) The Investor shall have executed each of the Transaction Documents and
delivered the same to the Company and Apexigen; 
 (b) The Merger shall have been completed and Apexigen shall have become a wholly owned
subsidiary of the Company; 
 (c) The Registration Statement covering the resale of all of the Commitment Shares and the Purchase
Shares shall have been declared effective under the Securities Act by the SEC and no stop order with respect to the Registration Statement shall be pending or threatened by the SEC; 

(d) The representations and warranties of the Investor shall be true and correct in all material respects (except to the extent that any of
such representations and warranties is already qualified as to materiality in Section 3 above, in which case, the portion of such representations and warranties so qualified shall be true and correct without further
qualification) as of the date hereof and as of the Commencement Date as though made at that time. 
  

	8.	 CONDITIONS TO THE INVESTOR’S OBLIGATION TO PURCHASE SHARES OF COMMON STOCK. 

The obligation of the Investor to buy Purchase Shares under this Agreement is subject to the satisfaction of each of the following conditions
on or prior to the Commencement Date and, once such conditions have been initially satisfied, there shall not be any ongoing obligation to satisfy such conditions after the Commencement has occurred: 

(a) Each of the Company and Apexigen shall have executed each of the Transaction Documents and delivered the same to the Investor; 

(b) The Merger shall have been completed and Apexigen shall have become a wholly owned subsidiary of the Company; 

(c) The Common Stock shall be listed or quoted on the Principal Market, trading in the Common Stock shall not have been suspended by the SEC
or the Principal Market within the last 365 days, and all Securities to be issued by the Company to the Investor pursuant to this Agreement shall have been approved for listing or quotation on the Principal Market in accordance with the applicable
rules and regulations of the Principal Market, as then in effect, subject only to official notice of issuance; 
 (d) The Investor shall
have received the opinions of the Company’s legal counsel dated as of the Commencement Date substantially in the form agreed by the parties hereto; 

  
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 (e) The representations and warranties of the Company and Apexigen shall be true and correct
in all material respects (except to the extent that any of such representations and warranties is already qualified as to materiality in Section 4 above, in which case, the portion of such representations and warranties so
qualified shall be true and correct without further qualification) as of the date hereof and as of the Commencement Date as though made at that time (except for representations and warranties that speak as of a specific date, which shall be true and
correct as of such date) and each of the Company and Apexigen shall have performed, satisfied and complied with the covenants, agreements and conditions required by the Transaction Documents to be performed, satisfied or complied with by the Company
and Apexigen, respectively, at or prior to the Commencement Date. The Investor shall have received a certificate, executed by the CEO, President or CFO of the Company, dated as of the Commencement Date, to the foregoing effect in the form attached
hereto as Exhibit A; 
 (f) The Board of Directors of the Company shall have adopted resolutions substantially in the form
previously provided to the Investor/as set forth as Exhibit C which shall be in full force and effect without any amendment or supplement thereto as of the Commencement Date; 

(g) As of the Commencement Date, the Company shall have reserved out of its authorized and unissued Common Stock, for the purpose of effecting
purchases of Purchase Shares hereunder and effecting the issuance of Commitment Shares hereunder, 17,316,667 shares of Common Stock; 
 (h)
The Commencement Irrevocable Transfer Agent Instructions and the Notice of Effectiveness of Registration Statement each shall have been delivered to and acknowledged in writing by the Company and the Company’s Transfer Agent (or any successor
transfer agent); 
 (i) if any Person commences a proceeding against the Company pursuant to or within the meaning of any Bankruptcy Law;

 (j) if the Company, pursuant to or within the meaning of any Bankruptcy Law, (i) commences a voluntary case, (ii) consents to
the entry of an order for relief against it in an involuntary case, (iii) consents to the appointment of a Custodian of it or for all or substantially all of its property, or (iv) makes a general assignment for the benefit of its creditors
or admits in writing that it is generally unable to pay its debts as the same become due; 
 (k) The Company shall have delivered to the
Investor (i) a certificate evidencing the incorporation and good standing of the Company in the State of Delaware issued by the Secretary of State of the State of Delaware and (ii) a certificate or its equivalent evidencing the good
standing of the Company as a foreign corporation in any other jurisdiction where the Company is duly qualified to conduct business, in each case, as of a date within ten (10) Business Days of the Commencement Date; 

(l) The Company shall have delivered to the Investor a certified copy of the Certificate of Incorporation as certified by the Secretary of
State of the State of Delaware within ten (10) Business Days of this Agreement; 
 (m) The Company shall have delivered to the Investor
a secretary’s certificate executed by the Secretary of the Company, dated as of the Commencement Date, in the form attached hereto as Exhibit B; 

(n) The Registration Statement covering the resale of the Commitment Shares and Purchase Shares shall have been declared effective
under the Securities Act by the SEC and no stop order with respect to the Registration Statement shall be pending or threatened by the SEC. The Company shall have prepared and filed with the SEC, not later than one (1) Business Day after the
effective date of the Registration Statement, a final and complete prospectus (the preliminary form of which shall be included in the 

  
 27 

 
Registration Statement) and shall have delivered to the Investor a true and complete copy thereof. Such prospectus shall be current and available for the resale by the Investor of all of the
Securities covered thereby. The Current Report shall have been filed with the SEC, as required pursuant to Section 5(a). All reports, schedules, registrations, forms, statements, information and other documents required to
have been filed by the Company with the SEC at or prior to the Commencement Date pursuant to the reporting requirements of the Exchange Act shall have been filed with the SEC within the applicable time periods prescribed for such filings under the
Exchange Act; 
 (o) No Event of Default has occurred, or any event which, after notice and/or lapse of time, would become an Event of
Default has occurred; 
 (p) All federal, state and local governmental laws, rules and regulations applicable to the transactions
contemplated by the Transaction Documents and necessary for the execution, delivery and performance of the Transaction Documents and the consummation of the transactions contemplated thereby in accordance with the terms thereof shall have been
complied with, and all consents, authorizations and orders of, and all filings and registrations with, all federal, state and local courts or governmental agencies and all federal, state and local regulatory or self-regulatory agencies necessary for
the execution, delivery and performance of the Transaction Documents and the consummation of the transactions contemplated thereby in accordance with the terms thereof shall have been obtained or made, including, without limitation, in each case
those required under the Securities Act, the Exchange Act, applicable state securities or “Blue Sky” laws or applicable rules and regulations of the Principal Market, or otherwise required by the SEC, the Principal Market or any state
securities regulators; 
 (q) No statute, regulation, order, decree, writ, ruling or injunction shall have been enacted, entered,
promulgated, threatened or endorsed by any federal, state, local or foreign court or governmental authority of competent jurisdiction which prohibits the consummation of or which would materially modify or delay any of the transactions contemplated
by the Transaction Documents; and 
 (r) No action, suit or proceeding before any federal, state, local or foreign arbitrator or any court
or governmental authority of competent jurisdiction shall have been commenced or threatened, and no inquiry or investigation by any federal, state, local or foreign governmental authority of competent jurisdiction shall have been commenced or
threatened, against the Company or Apexigen, or any of the officers, directors or affiliates of the Company or Apexigen, seeking to restrain, prevent or change the transactions contemplated by the Transaction Documents, or seeking material damages
in connection with such transactions. 
  

	9.	 INDEMNIFICATION. 

(a) In consideration of the Investor’s execution and delivery of the Transaction Documents and acquiring the Securities hereunder and in
addition to all of the Company’s other obligations under the Transaction Documents, the Company shall defend, protect, indemnify and hold harmless the Investor and all of its affiliates, stockholders, officers, directors, members, managers,
employees and direct or indirect investors and any of the foregoing Person’s agents or other representatives (including, without limitation, those retained in connection with the transactions contemplated by this Agreement) (collectively, the
“Indemnitees”) from and against any and all actions, causes of action, suits, claims, losses, costs, penalties, fees, liabilities and damages, and reasonable expenses in connection therewith (irrespective of whether any such
Indemnitee is a party to the action for which indemnification hereunder is sought), and including reasonable and documented out-of-pocket attorneys’ fees and
disbursements (the “Indemnified Liabilities”), actually incurred by any Indemnitee as a result of, or arising out of, or relating to (a) any misrepresentation or breach of any representation or warranty made by the Company in
the Transaction Documents or any other certificate, instrument or document executed by the Company contemplated hereby 

  
 28 

 
or thereby, (b) any breach of any covenant, agreement or obligation of the Company contained in the Transaction Documents or any other certificate, instrument or document contemplated hereby
or thereby, or (c) any cause of action, suit or claim brought or made against such Indemnitee and arising out of or resulting from the execution, delivery, performance or enforcement of the Transaction Documents or any other certificate,
instrument or document contemplated hereby or thereby, other than, in the case of clause (c), with respect to Indemnified Liabilities which result directly and primarily from the fraud, gross negligence, bad faith or willful misconduct of an
Indemnitee. The indemnity in this Section 9(a) shall not apply to amounts paid in settlement of any claim if such settlement is effected without the prior written consent of the Company, which consent shall not be
unreasonably withheld, conditioned or delayed. To the extent that the foregoing undertaking by the Company may be unenforceable for any reason, the Company shall make the maximum contribution to the payment and satisfaction of each of the
Indemnified Liabilities which is permissible under applicable law. Payment under this indemnification shall be made within thirty (30) days from the date the Investor makes written request for it. A certificate containing reasonable detail as
to the amount of such indemnification submitted to the Company by the Investor shall be conclusive evidence, absent manifest error, of the amount due from the Company to the Investor; provided that the Indemnitee shall undertake to repay any amounts
paid to it hereunder if it is ultimately determined, by a final and non-appealable order of a court of competent jurisdiction, that the Indemnitee is not entitled to be indemnified against such Indemnified
Liabilities by the Company pursuant to this Agreement. If any action shall be brought against any Indemnitee in respect of which indemnity may be sought pursuant to this Agreement, such Indemnitee shall promptly notify the Company in writing, and
the Company shall have the right to assume the defense thereof with counsel of its own choosing reasonably acceptable to the Indemnitee. Any Indemnitee shall have the right to employ separate counsel in any such action and participate in the defense
thereof, but the fees and expenses of such counsel shall be at the expense of such Indemnitee, except to the extent that (i) the employment thereof has been specifically authorized by the Company in writing, (ii) the Company has failed
after a reasonable period of time to assume such defense and to employ counsel or (iii) in such action there is, in the reasonable opinion of such separate counsel, a material conflict on any material issue between the position of the Company
and the position of such Indemnitee, in which case the Company shall be responsible for the reasonable and documented out-of-pocket fees and expenses of no more than one
such separate counsel. 
 (b) In consideration of the Investor’s execution and delivery of the Transaction Documents and acquiring the
Securities hereunder and in addition to all of Apexigen’s other obligations under the Transaction Documents, Apexigen shall defend, protect, indemnify and hold harmless the Investor and all of its Indemnitees from and against any and all
Indemnified Liabilities, actually incurred by any Indemnitee as a result of, or arising out of, or relating to (a) any misrepresentation or breach of any representation or warranty made by Apexigen in the Transaction Documents or any other
certificate, instrument or document contemplated hereby or thereby, (b) any breach of any covenant, agreement or obligation of Apexigen contained in the Transaction Documents or any other certificate, instrument or document executed by Apexigen
contemplated hereby or thereby, or (c) any cause of action, suit or claim brought or made against such Indemnitee and arising out of or resulting from the execution, delivery, performance or enforcement of the Transaction Documents or any other
certificate, instrument or document contemplated hereby or thereby, other than, in the case of clause (c), with respect to Indemnified Liabilities which result from the fraud, gross negligence, bad faith or willful misconduct of an Indemnitee. The
indemnity in this Section 9(b) shall not apply to amounts paid in settlement of any claim if such settlement is effected without the prior written consent of Apexigen, which consent shall not be unreasonably withheld,
conditioned or delayed. To the extent that the foregoing undertaking by Apexigen may be unenforceable for any reason, Apexigen shall make the maximum contribution to the payment and satisfaction of each of the Indemnified Liabilities which is
permissible under applicable law. Payment under this indemnification shall be made within thirty (30) days from the date Investor makes written request for it. A certificate containing reasonable detail as to the amount of such indemnification
submitted to Apexigen by the Investor shall be conclusive evidence, absent manifest error, of the amount due from Apexigen to the Investor; provided that 

  
 29 

 
the Indemnitee shall undertake to repay any amounts paid to it hereunder if it is ultimately determined, by a final and non-appealable order of a court of
competent jurisdiction, that the Indemnitee is not entitled to be indemnified against such Indemnified Liabilities by Apexigen pursuant to this Agreement. If any action shall be brought against any Indemnitee in respect of which indemnity may be
sought pursuant to this Agreement, such Indemnitee shall promptly notify Apexigen in writing, and Apexigen shall have the right to assume the defense thereof with counsel of its own choosing reasonably acceptable to the Indemnitee. Any Indemnitee
shall have the right to employ separate counsel in any such action and participate in the defense thereof, but the fees and expenses of such counsel shall be at the expense of such Indemnitee, except to the extent that (i) the employment
thereof has been specifically authorized by Apexigen in writing, (ii) Apexigen has failed after a reasonable period of time to assume such defense and to employ counsel or (iii) in such action there is, in the reasonable opinion of such
separate counsel, a material conflict on any material issue between the position of Apexigen and the position of such Indemnitee, in which case Apexigen shall be responsible for the reasonable and documented out-of-pocket fees and expenses of no more than one such separate counsel. Notwithstanding the foregoing, any indemnification provided by the Company and Apexigen shall be netted against each other so as not
to result in duplicate recoveries for the same Losses 
  

	10.	 EVENTS OF DEFAULT. 

An “Event of Default” shall be deemed to have occurred at any time subsequent to the consummation of the Merger as any of the
following events occurs: 
 (a) the effectiveness of a registration statement registering the resale of the Securities lapses for any reason
(including, without limitation, the issuance of a stop order or similar order) or such registration statement (or the prospectus forming a part thereof) is unavailable to the Investor for resale of any or all of the Securities to be issued to the
Investor under the Transaction Documents, and such lapse or unavailability continues for a period of ten (10) consecutive Business Days or for more than an aggregate of thirty (30) Business Days in any
365-day period, but excluding a lapse or unavailability where (i) the Company terminates a registration statement after the Investor has confirmed in writing that all of the Securities covered thereby
have been resold or (ii) the Company supersedes one registration statement with another registration statement, including (without limitation) by terminating a prior registration statement when it is effectively replaced with a new registration
statement covering Securities (provided in the case of this clause (ii) that all of the Securities covered by the superseded (or terminated) registration statement that have not theretofore been resold are included in the superseding (or new)
registration statement). 
 (b) the suspension of the Common Stock from trading on the Principal Market for a period of one
(1) Business Day (other than in connection with a general suspension of trading on the Principal Market), provided that the Company may not direct the Investor to purchase any shares of Common Stock during any such suspension; 

(c) the delisting of the Common Stock from The Nasdaq Capital Market, provided, however, that the Common Stock is not immediately thereafter
trading on the New York Stock Exchange, The Nasdaq Global Market, The Nasdaq Global Select Market, the NYSE American, the NYSE Arca, the OTC Bulletin Board, the OTCQX operated by the OTC Markets Group, Inc., the OTCQB operated by the OTC Markets
Group, Inc. or such other nationally recognized trading market (or nationally recognized successor to any of the foregoing); 
 (d) If at
any time after the Commencement Date, the Exchange Cap is reached unless and until stockholder approval is obtained pursuant to Section 2(f) hereof. The Exchange Cap shall be deemed to be reached at such time if, upon
submission of a Regular Purchase Notice or Accelerated Purchase Notice under this Agreement, the issuance of such shares of Common Stock would exceed that number of shares of Common Stock which the Company may issue without breaching the
Company’s obligations under the rules or regulations of the Principal Market; 

  
 30 

 (e) the failure for any reason by the Transfer Agent to issue (i) the Initial
Commitment Shares to the Investor within three (3) Business Days of the date of closing of the Merger pursuant to Section 5(e) hereof, (ii) the Additional Commitment Shares to the Investor within three
(3) Business Days after the Additional Commitment Share Delivery Date pursuant to Section 5(e) hereof, and (iii) the Purchase Shares to the Investor within three (3) Business Days after the applicable
Purchase Date, Accelerated Purchase Date or Additional Accelerated Purchase Date (as applicable) on which the Investor is entitled to receive such Purchase Shares; 

(f) the Company or Apexigen breaches any representation, warranty, covenant or other term or condition under any Transaction Document if such
breach could have a Company Material Adverse Effect or an Apexigen Material Adverse Effect (as applicable) and except, in the case of a breach of a covenant which is reasonably curable, only if such breach continues for a period of at least five
(5) Business Days; 
 (g) if any Person commences a proceeding against the Company pursuant to or within the meaning of any Bankruptcy
Law; 
 (h) if the Company, pursuant to or within the meaning of any Bankruptcy Law, (i) commences a voluntary case, (ii) consents
to the entry of an order for relief against it in an involuntary case, (iii) consents to the appointment of a Custodian of it or for all or substantially all of its property, or (iv) makes a general assignment for the benefit of its
creditors or is generally unable to pay its debts as the same become due; 
 (i) a court of competent jurisdiction enters an order or decree
under any Bankruptcy Law that (i) is for relief against the Company in an involuntary case, (ii) appoints a Custodian of the Company or for all or substantially all of its property, or (iii) orders the liquidation of the Company or
any Subsidiary; or 
 (j) if at any time the Company is not eligible to transfer its Common Stock electronically as DWAC Shares. 

In addition to any other rights and remedies under applicable law and this Agreement, so long as an Event of Default has occurred and is
continuing, or if any event which, after notice and/or lapse of time, would become an Event of Default, has occurred and is continuing, the Company shall not deliver to the Investor any Regular Purchase Notice or Accelerated Purchase Notice. 

 

	11.	 TERMINATION 

This Agreement may be terminated only as follows: 

(a) If pursuant to or within the meaning of any Bankruptcy Law, the Company commences a voluntary case or any Person commences a proceeding
against the Company, a Custodian is appointed for the Company or for all or substantially all of its property, or the Company makes a general assignment for the benefit of its creditors (any of which must be an Event of Default as described in
Sections 10(g), 10(h) and 10(i) hereof), this Agreement shall automatically terminate without any liability or payment to the Company (except as set forth below) without further action or notice by any Person; provided that, in
connection with an Event of Default described in Section 10(g), this Agreement shall only terminate if any such proceeding shall continue for sixty (60) days without being dismissed, bonded or discharged. 

  
 31 

 (b) In the event that the Commencement shall not have occurred on or before December 1,
2022, due to the failure to satisfy the conditions set forth in Sections 7 and 8 above with respect to the Commencement, then this Agreement may be terminated by any party at the close of business on December 1, 2022 or
thereafter, in each case without liability of such party to the other party (except as set forth below); provided, however, that the right to terminate this Agreement under this Section 11(b) shall not be available to any
party if such party is then in breach of any covenant or agreement contained in this Agreement or any representation or warranty of such party contained in this Agreement fails to be true and correct such that the conditions set forth in
Section 7(d) or Section 8(e), as applicable, could not then be satisfied; provided, further, however that if the full amount of the Commitment Shares have been paid to Investor, Investor shall not
have the right to terminate this Agreement pursuant to this Section 11(b). 
 (c) At any time after the Commencement Date, the
Company shall have the option to terminate this Agreement for any reason or for no reason by delivering notice (a “Company Termination Notice”) to the Investor electing to terminate this Agreement without any liability whatsoever of
any party to any other party under this Agreement (except as set forth below). The Company Termination Notice shall not be effective until one (1) Business Day after it has been received by the Investor. 

(d) This Agreement shall automatically terminate on the earlier of (i) the date that the Company sells and the Investor purchases
(including by payment of the applicable Purchase Price) the full Available Amount as provided herein, without any action or notice on the part of any party and without any liability whatsoever of any party to any other party under this Agreement
(except as set forth below), (ii) the date that the Business Combination Agreement, dated as of March 17, 2022 by and among the Company, Apexigen, and Project Barolo Merger Sub, Inc. (the “BCA”), is terminated, and
(iii) the Outside Date (as defined in the BCA) if the Merger has not occurred by such date. 
 Except as set forth in Sections 11(a) (in respect
of an Event of Default under Sections 10(g), 10(h) and 10(i)), and 11(d), any termination of this Agreement pursuant to this Section 11 shall be effected by written notice from the Company
to the Investor, or the Investor to the Company, as the case may be, setting forth the basis for the termination hereof. The representations and warranties and covenants of the Company and the Investor contained in Sections 3, 4, 5
(excluding Sections 5(f) and 5(m)), and 6 hereof, the indemnification provisions set forth in Section 9 hereof and the agreements and covenants set forth in Sections 11 and 12
shall survive the execution and delivery of this Agreement and any termination of this Agreement. If this Agreement is terminated prior to the issuance of any Purchase Shares or prior to the completion of the Merger, Sections 5 and 6 shall not
survive such termination. No termination of this Agreement shall (i) affect the Company’s or the Investor’s rights or obligations under (A) this Agreement with respect to then pending Regular Purchases, Accelerated Purchases, and
Additional Accelerated Purchases and the Company and the Investor shall complete their respective obligations with respect to any pending Regular Purchases, Accelerated Purchases and Additional Accelerated Purchases under this Agreement and
(B) the Registration Rights Agreement, which shall survive any such termination, or (ii) be deemed to release the Company or the Investor from any liability for intentional misrepresentation or willful breach of any of the Transaction
Documents. 
  

	12.	 MISCELLANEOUS. 

(a) Governing Law; Jurisdiction; Jury Trial. The corporate laws of the State of Delaware shall govern all issues concerning the relative
rights of the Company and its stockholders. All other questions concerning the construction, validity, enforcement and interpretation of this Agreement and the other Transaction Documents shall be governed by the internal laws of the State of New
York, without giving effect to any choice of law or conflict of law provision or rule (whether of the State of New York or any other jurisdictions) that would cause the application of the laws of any jurisdictions other than the State of New York.
Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal 

  
 32 

 
courts sitting in the State of New York, Borough of Manhattan, for the adjudication of any dispute hereunder or under the other Transaction Documents or in connection herewith or therewith, or
with any transaction contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such
suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit, action or proceeding is improper. Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit,
action or proceeding by mailing a copy thereof to such party at the address for such notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein
shall be deemed to limit in any way any right to serve process in any manner permitted by law. EACH PARTY HEREBY IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE, AND AGREES NOT TO REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE
HEREUNDER OR IN CONNECTION HEREWITH OR ARISING OUT OF THIS AGREEMENT OR ANY TRANSACTION CONTEMPLATED HEREBY. 
 (b) Counterparts.
This Agreement may be executed in two or more identical counterparts, all of which shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party; provided
that a facsimile signature or signature delivered by e-mail in a “.pdf” format data file shall be considered due execution and shall be binding upon the signatory thereto with the same force and
effect as if the signature were an original signature. 
 (c) Headings. The headings of this Agreement are for convenience of
reference and shall not form part of, or affect the interpretation of, this Agreement. 
 (d) Severability. If any provision of this
Agreement shall be invalid or unenforceable in any jurisdiction, such invalidity or unenforceability shall not affect the validity or enforceability of the remainder of this Agreement in that jurisdiction or the validity or enforceability of any
provision of this Agreement in any other jurisdiction. 
 (e) Entire Agreement. The Transaction Documents supersede all other prior
oral or written agreements between the Investor, the Company, their affiliates and Persons acting on their behalf with respect to the subject matter thereof, and this Agreement, the other Transaction Documents and the instruments referenced herein
contain the entire understanding of the parties with respect to the matters covered herein and therein and, except as specifically set forth herein or therein, neither the Company nor the Investor makes any representation, warranty, covenant or
undertaking with respect to such matters. The Company acknowledges and agrees that is has not relied on, in any manner whatsoever, any representations or statements, written or oral, other than as expressly set forth in the Transaction Documents.

 (f) Notices. Any notices, consents or other communications required or permitted to be given under the terms of this Agreement
must be in writing and will be deemed to have been delivered: (i) upon receipt when delivered personally; (ii) upon receipt when sent by facsimile or email (provided confirmation of transmission is mechanically or electronically generated
and kept on file by the sending party); or (iii) one Business Day after deposit with a nationally recognized overnight delivery service, in each case properly addressed to the party to receive the same. The addresses for such communications
shall be: 
 If to the Company: 
  

			
	Brookline Capital Acquisition Corp.
	280 Park Avenue, Suite 43W
	New York, NY 10017
	Phone:	  	646-603-6716
	Attention:	  	Samuel P. Wertheimer, Chairman and CEO
	Email:	  	***

  
 33 

 With a copy to: 

 

			
	DLA Piper LLP (US)
	1251 Avenue of the Americas
	New York, NY 10020
	Attention: James Kelly; Peter Ekberg
	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 Apexigen: 

 

			
	Apexigen, Inc.
	75 Shoreway Rd., Suite C
	San Carlos, CA 94070
	Phone:	  	***
	Attention:	  	Xiaodong Yang, MD, PhD, President and CEO; Francis Sarena, Chief Operating Officer
	Email:	  	***

 With a copy to: 

 

			
	Wilson Sonsini 650 Mill Page Road
	Palo Alto, CA 94304
	Phone:	  	650-493-9300
	Attention:	  	Kenneth A. Clark; Michael E. Coke; Lance E. Brady
	Email:	  	kclark@wsgr.com; mcoke@wsgr.com; lbrady@wsgr.com

 If to the Investor: 

 

			
	Lincoln Park Capital Fund, LLC
	440 North Wells, Suite 410
	Chicago, IL 60654
	Telephone:	  	312.822.9300
	Facsimile:	  	312.822.9301
	E-mail:	  	***
	Attention:	  	Josh Scheinfeld/Jonathan Cope

  
 34 

 With a copy to (which shall not constitute notice or service of process): 

 

			
	K&L Gates, LLP 200 S. Biscayne Blvd., Ste. 3900
	Miami, Florida 33131
	Telephone:	  	305.539.3306
	Facsimile:	  	305.358.7095
	E-mail:	  	clayton.parker@klgates.com
	Attention:	  	Clayton E. Parker, Esq.

 If to the Transfer Agent: 

 

			
	Continental Stock Transfer & Trust
	1 State Street 30th Floor
	New York, NY 10004-1561
	Attention:	  	Douglas Reed
	E-mail:	  	***

 or at such other address and/or facsimile number and/or to the attention of such other Person as the recipient party has
specified by written notice given to each other party two (2) Business Days prior to the effectiveness of such change. Written confirmation of receipt (A) given by the recipient of such notice, consent or other communication,
(B) mechanically or electronically generated by the sender’s facsimile machine or email account containing the time, date, and recipient facsimile number or email address, as applicable, and an image of the first page of such transmission
or (C) provided by a nationally recognized overnight delivery service, shall be rebuttable evidence of personal service, receipt by facsimile, email or receipt from a nationally recognized overnight delivery service in accordance with clause
(i), (ii) or (iii) above, respectively. 
 (g) Successors and Assigns. This Agreement shall be binding upon and inure to the
benefit of the parties and their respective successors and assigns. Neither Company nor Apexigen shall not assign this Agreement or any rights or obligations hereunder without the prior written consent of the Investor, including by merger or
consolidation. The Investor may not assign its rights or obligations under this Agreement. 
 (h) No Third Party Beneficiaries. This
Agreement is intended for the benefit of the parties hereto and their respective permitted successors and assigns, and is not for the benefit of, nor may any provision hereof be enforced by, any other Person. 

(i) Publicity. Each of the Company and Apexigen shall afford the Investor and its counsel with the opportunity to review and comment
upon, shall consult with the Investor and its counsel on the form and substance of, and shall give due consideration to all such comments from the Investor or its counsel on, any press release, SEC filing, or any other public disclosure by or on
behalf of the Company or Apexigen relating to the Investor, its purchases hereunder or any aspect of the Transaction Documents or the transactions contemplated thereby, not less than 24 hours prior to the issuance, filing or public disclosure
thereof. The Investor must be provided with a final version of any such press release, SEC filing, or other public disclosure at least 24 hours prior to any release, filing, or public use by the Company thereof; provided however, that the
Company’s obligations pursuant to this Section 12(i) shall not apply if the form and substance of such press release, SEC filing, or other public disclosure relating to the Investor, its purchases hereunder or any
aspect of the Transaction Documents or the transactions contemplated thereby previously have been publicly disclosed by the Company in compliance with this Section 12(i). The Company agrees and acknowledges that its failure
to fully comply with this provision constitutes a Company Material Adverse Effect, and Apexigen agrees and acknowledges that its failure to fully comply with this provision constitutes an Apexigen Material Adverse Effect. 

  
 35 

 (j) Further Assurances. Each party shall do and perform, or cause to be done and
performed, all such further acts and things, and shall execute and deliver all such other agreements, certificates, instruments and documents, as the other party may reasonably request in order to consummate and make effective, as soon as reasonably
possible, the Commencement, and to carry out the intent and accomplish the purposes of this Agreement and the consummation of the transactions contemplated hereby. 

(k) No Financial Advisor, Placement Agent, Broker or Finder. Each of the Company and Apexigen represents and warrants to
the Investor that, except as disclosed on Schedule, it has not engaged any financial advisor, placement agent, broker or finder in connection with the transactions contemplated hereby. The Investor represents and warrants to the Company and Apexigen
that it has not engaged any financial advisor, placement agent, broker or finder in connection with the transactions contemplated hereby. Each of the Company and Apexigen shall be responsible for the payment of any fees or commissions, if any, of
any financial advisor, placement agent, broker or finder engaged by it relating to or arising out of the transactions contemplated hereby. Each of the Company and Apexigen shall pay, and hold the Investor harmless against, any liability, loss or
expense (including, without limitation, reasonable attorneys’ fees and out of pocket expenses) arising in connection with any such claim. 

(l) No Strict Construction. The language used in this Agreement will be deemed to be the language chosen by the parties to express
their mutual intent, and no rules of strict construction will be applied against any party. 
 (m) Remedies, Other
Obligations, Breaches and Injunctive Relief. The Investor’s remedies provided in this Agreement, including, without limitation, the Investor’s remedies provided in Section 9, shall be cumulative and in addition to all other
remedies available to the Investor under this Agreement, at law or in equity (including a decree of specific performance and/or other injunctive relief), no remedy of the Investor contained herein shall be deemed a waiver of compliance with the
provisions giving rise to such remedy and nothing herein shall limit the Investor’s right to pursue actual damages for any failure by the Company to comply with the terms of this Agreement. Each of the Company and Apexigen acknowledges that a
breach by it of its obligations hereunder will cause irreparable harm to the Investor and that the remedy at law for any such breach may be inadequate. Each of the Company and Apexigen therefore agrees that, in the event of any such breach or
threatened breach, the Investor shall be entitled, in addition to all other available remedies, to an injunction restraining any breach, without the necessity of showing economic loss and without any bond or other security being required. 

(n) Enforcement Costs. If: (i) this Agreement is placed by the Investor in the hands of an attorney for enforcement or is enforced
by the Investor through any legal proceeding; (ii) an attorney is retained to represent the Investor in any bankruptcy, reorganization, receivership or other proceedings affecting creditors’ rights and involving a claim under this
Agreement; or (iii) an attorney is retained to represent the Investor in any other proceedings whatsoever in connection with this Agreement, then Company and Apexigen, severally and not jointly, shall pay to the Investor, as incurred by the
Investor, all reasonable costs and expenses including reasonable attorneys’ fees incurred in connection therewith, in addition to all other amounts due hereunder. 

(o) Amendment and Waiver; Failure or Indulgence Not Waiver. No provision of this Agreement may be amended or waived by the parties from
and after the date that is one (1) Business Day immediately preceding the filing of the Registration Statement with the SEC. Subject to the immediately preceding sentence, (i) no provision of this Agreement may be amended other than by a
written instrument signed by both parties hereto and (ii) no provision of this Agreement may be waived other than in a written 

  
 36 

 
instrument signed by the party against whom enforcement of such waiver is sought. No failure or delay in the exercise of any power, right or privilege hereunder shall operate as a waiver thereof,
nor shall any single or partial exercise of any such power, right or privilege preclude other or further exercise thereof or of any other right, power or privilege. 

(p) Adjustments for Share Splits. The parties acknowledge and agree that all share-related numbers contained in this Agreement shall be
adjusted to take into account any reorganization, recapitalization, non-cash dividend, stock split or other similar transaction effected with respect to the Common Stock except as specifically stated herein.

 ** Signature Page Follows ** 

  
 37 

 IN WITNESS WHEREOF, the Investor and the Company have caused this Purchase Agreement
to be duly executed as of the date first written above. 
  

			
	THE COMPANY:
	
	BROOKLINE CAPITAL ACQUISITION CORP.
		
	By:	 	 /s/ Dr. Samuel P. Wertheimer

	Name:	 	Dr. Samuel P. Wertheimer
	Title:	 	Chief Executive Officer and Chairman
	
	APEXIGEN:
	
	APEXIGEN, INC.
		
	By:	 	 /s/ Xiaodong Yang

	Name:	 	Xiaodong Yang
	Title:	 	Chief Executive Officer
	
	THE INVESTOR:
	
	LINCOLN PARK CAPITAL FUND, LLC
	BY: LINCOLN PARK CAPITAL, LLC
	BY: ROCKLEDGE CAPITAL CORPORATION
		
	By:	 	 /s/ Josh Scheinfeld

	Name:	 	Josh Scheinfeld
	Title:	 	President

  
 38 

 DISCLOSURE SCHEDULE 

The following are exceptions to the representations and warranties of Brookline Capital Acquisition Corp., a Delaware corporation (the
“Company”) and Apexigen, Inc., a Delaware corporation (“Apexigen”), contained in Sections 4(a) and 4(b) of that certain Purchase Agreement by and among the Company, Apexigen, and Lincoln Park Capital Fund, LLC, an
Illinois limited liability company (the “Investor”), dated as of March 17, 2022 (the “Purchase Agreement”), and should be considered an integral part of the Purchase Agreement. This Disclosure Schedule is
arranged in sections corresponding to the numbered sections and subsections contained in Sections 4(a) and 4(b) of the Purchase Agreement, and the disclosures in any section or subsection of this Disclosure Schedule shall qualify other sections and
subsections in Sections 4 (a) and 4(b) of the Purchase Agreement to the extent it is reasonably apparent from the reading of the disclosure that such disclosure is applicable to such other sections or subsections. Any terms defined in the Purchase
Agreement shall have the same meaning when used herein as when used in the Purchase Agreement, unless the context otherwise requires. Nothing in this Disclosure Schedule is intended to broaden the scope of any representation or warranty contained in
the Purchase Agreement or to create any covenant. The inclusion of any item hereunder shall not be deemed to be an admission by the Company or Apexigen that such item is not in the ordinary course of business or material to the business, assets or
results of operations of the Company or Apexigen, and it shall not be deemed an admission of any obligation or liability to any third party. 

  
 39 

 EXHIBITS 

 

			
	Exhibit A	  	Form of Officer’s Certificate
	Exhibit B	  	Form of Secretary’s Certificate
	Exhibit C	  	Form of Resolutions of the Board of Directors of the Company

  
 40 

 EXHIBIT A 

FORM OF OFFICER’S CERTIFICATE 

This Officer’s Certificate (“Certificate”) is being delivered pursuant to Section 8(e) of that
certain Purchase Agreement dated as of March 17, 2022, (“Purchase Agreement”), by and among BROOKLINE CAPITAL ACQUISITION CORP., a Delaware corporation (the “Company”), APEXIGEN, INC., a Delaware
corporation, and LINCOLN PARK CAPITAL FUND, LLC (the “Investor”). Terms used herein and not otherwise defined shall have the meanings ascribed to them in the Purchase Agreement. 

The undersigned, ___________, ______________ of the Company, hereby certifies, on behalf of the Company and not in his individual capacity, as
follows: 
 1. I am the _____________ of the Company and make the statements contained in this Certificate; 

2. The representations and warranties of the Company in the Purchase Agreement are true and correct in all material respects
(except to the extent that any of such representations and warranties is already qualified as to materiality in Section 4 of the Purchase Agreement, in which case, such representations and warranties are true and correct without further
qualification) as of the date when made and as of the Commencement Date as though made at that time (except for representations and warranties that speak as of a specific date, in which case such representations and warranties are true and correct
as of such date); 
 3. The Company has performed, satisfied and complied in all material respects with the covenants,
agreements and conditions required by the Transaction Documents to be performed, satisfied or complied with by the Company at or prior to the Commencement Date. 

4. The Company has not taken any steps, and does not currently expect to take any steps, to seek protection pursuant to any
Bankruptcy Law nor does the Company or any of its Subsidiaries have any knowledge or reason to believe that its creditors intend to initiate involuntary bankruptcy or insolvency proceedings. 

IN WITNESS WHEREOF, I have hereunder signed my name on this ___ day of ___________. 

 

	
	  
 Name:

	Title:

 The undersigned as Secretary of BROOKLINE CAPITAL ACQUISITION CORP., a Delaware corporation,
hereby certifies that ___________ is the duly elected, appointed, qualified and acting ________ of _________ and that the signature appearing above is his genuine signature. 

 

	
	  
 Secretary

  
 41 

 EXHIBIT B 

FORM OF SECRETARY’S CERTIFICATE 

This Secretary’s Certificate (“Certificate”) is being delivered pursuant to Section 8(k) of that
certain Purchase Agreement dated as of March 17, 2022 (“Purchase Agreement”), by and among BROOKLINE CAPITAL ACQUISITION CORP., a Delaware corporation (the “Company”) and LINCOLN PARK CAPITAL FUND, LLC (the
“Investor”), pursuant to which the Company may sell to the Investor up to Fifty Million Dollars ($50,000,000) of the Company’s Common Stock, $0.0001 par value per share (the “Common Stock”). Terms used herein and not
otherwise defined shall have the meanings ascribed to them in the Purchase Agreement. 
 The undersigned, ____________, Secretary of the
Company, hereby certifies, on behalf of the Company and not in his individual capacity, as follows: 
 1. I am the Secretary
of the Company and make the statements contained in this Secretary’s Certificate. 
 2. Attached hereto as Exhibit
A and Exhibit B are true, correct and complete copies of the Company’s Bylaws (“Bylaws”) and Certificate of Incorporation (“Charter”), in each case, as amended through the date hereof, and no action has been taken
by the Company, its directors, officers or stockholders, in contemplation of the filing of any further amendment relating to or affecting the Bylaws or Charter. 

3. Attached hereto as Exhibit C are true, correct and complete copies of the resolutions duly adopted by the Board of
Directors of the Company on _____________, at which a quorum was present and acting throughout. Such resolutions have not been amended, modified or rescinded and remain in full force and effect and such resolutions are the only resolutions adopted
by the Company’s Board of Directors, or any committee thereof, or the stockholders of the Company relating to or affecting (i) the entering into and performance of the Purchase Agreement, or the issuance, offering and sale of the Purchase
Shares and the Commitment Shares and (ii) and the performance of the Company of its obligation under the Transaction Documents as contemplated therein. 

4. As of the date hereof, the authorized, issued and reserved capital stock of the Company is as set forth on Exhibit D
hereto. 
 IN WITNESS WHEREOF, I have hereunder signed my name on this ___ day of ____________. 

 

	
	  

	Secretary

 The undersigned as ___________ of BROOKLINE CAPITAL ACQUISITION CORP., a Delaware corporation, hereby certifies
that ____________ is the duly elected, appointed, qualified and acting Secretary of _________, and that the signature appearing above is his genuine signature. 

  
 42 

 EXHIBIT C 

FORM OF RESOLUTIONS 
 OF
THE BOARD OF DIRECTORS OF THE COMPANY 
 UNANIMOUS WRITTEN CONSENT OF 

BROOKLINE CAPITAL ACQUISITION CORP. 

In accordance with the corporate laws of the state of Delaware, the undersigned, being all of the directors of BROOKLINE CAPITAL
ACQUISITION CORP., a Delaware corporation (the “Company”) do hereby consent to and adopt the following resolutions as the action of the Board of Directors for and on behalf of the Company and hereby direct that this Consent be
filed with the minutes of the proceedings of the Board of Directors: 
 WHEREAS, there has been presented to the Board of Directors of the
Company a draft of the Purchase Agreement (the “Purchase Agreement”) by and among the Company, Apexigen, Inc. (“Apexigen”) and Lincoln Park Capital Fund, LLC (“Lincoln Park”), providing for the
purchase by Lincoln Park of up to Fifty Million Dollars ($50,000,000) of the Company’s common stock, $0.0001 par value per share (the “Common Stock”). 

Transaction Documents 

NOW, THEREFORE, BE IT RESOLVED,, after careful consideration of the Purchase Agreement, the documents incident thereto and other factors
deemed relevant by the Board of Directors, the Board of Directors has determined that it is advisable and in the best interests of the Company to engage in the transactions contemplated by the Purchase Agreement, including, but not limited to, the
issuance of 150,000 shares of Common Stock to Lincoln Park as an initial commitment fee (the “Initial Commitment Shares”) and the sale of shares of Common Stock to Lincoln Park up to the available amount under the Purchase Agreement
(the “Purchase Shares”). 
 FURTHER RESOLVED, that the transactions described in the Purchase Agreement are hereby approved
and [•] and [•] (the “Authorized Officers”) are severally authorized to execute and deliver the Purchase Agreement, and any other agreements or documents contemplated thereby including, without limitation, a registration
rights agreement (the “Registration Rights Agreement”) providing for the registration of the shares of the Company’s Common Stock issuable in respect of the Purchase Agreement on behalf of the Company, with such amendments,
changes, additions and deletions as the Authorized Officers may deem to be appropriate and approve on behalf of, the Company, such approval to be conclusively evidenced by the signatures of the Authorized Officers thereon; and 

FURTHER RESOLVED, that the terms and provisions of the Registration Rights Agreement by and among the Company and Lincoln Park are hereby
approved and the Authorized Officers are authorized to execute and deliver the Registration Rights Agreement (pursuant to the terms of the Purchase Agreement), with such amendments, changes, additions and deletions as the Authorized Officers may
deem appropriate and approve on behalf of, the Company, such approval to be conclusively evidenced by the signature of an Authorized Officer thereon; and 

FURTHER RESOLVED, that the terms and provisions of the forms of Commencement Irrevocable Transfer Agent Instructions and Notice of
Effectiveness of Registration Statement (collectively, the “Instructions”) are hereby approved and the Authorized Officers are authorized to execute and deliver the Instructions on behalf of the Company in accordance with the
Purchase Agreement, with such amendments, changes, additions and deletions as the Authorized Officers may deem appropriate and approve on behalf of, the Company, such approval to be conclusively evidenced by the signature of an Authorized Officer
thereon; and 

  
 43 

 Execution of Purchase Agreement 

FURTHER RESOLVED, that the Company be and it hereby is authorized to execute the Purchase Agreement providing for the purchase of up to Fifty
Million Dollars ($50,000,000) of the Company’s Common Stock; and 
 Issuance of Common Stock 

FURTHER RESOLVED, that the Company is hereby authorized to issue to Lincoln Park 150,000 shares of Common Stock as the Initial Commitment
Shares, and that upon issuance of the Initial Commitment Shares pursuant to the Purchase Agreement, the Initial Commitment Shares shall be duly authorized, validly issued, fully paid and nonassessable with no personal liability attaching to the
ownership thereof; and 
 FURTHER RESOLVED, that the Company is hereby authorized to issue $1,500,000 of shares of Common Stock (subject to
equitable adjustment for any reorganization, recapitalization, non-cash dividend, stock split or other similar transaction) as Additional Commitment Shares (together with the Initial Commitment Shares, the
“Commitment Shares”) in accordance with the Section 5(e) of the Purchase Agreement and that, upon issuance, such Additional Commitment Shares will be duly authorized, validly issued, fully paid and nonassessable with no personal
liability attaching to the ownership thereof; and 
 FURTHER RESOLVED, that the Company shall reserve 650,000 of shares of Common Stock
(subject to equitable adjustment for any reorganization, recapitalization, non-cash dividend, stock split or other similar transaction) for issuance as Commitment Shares under the Purchase Agreement, and the
Company shall adjust such reserve from time to time as shall be necessary, proper or desirable to carry into effect the purpose, obligations under, and intent of the Purchase Agreement; and 

FURTHER RESOLVED, that the Company is hereby authorized to issue shares of Common Stock upon the purchase of Purchase Shares up to the
Available Amount under the Purchase Agreement in accordance with the terms of the Purchase Agreement and that, upon issuance of the Purchase Shares pursuant to the Purchase Agreement, the Purchase Shares will be duly authorized, validly issued,
fully paid and nonassessable with no personal liability attaching to the ownership thereof; and 
 FURTHER RESOLVED, that the Company shall
initially reserve 16,666,667 shares of Common Stock for issuance as Purchase Shares under the Purchase Agreement, and the Company shall adjust such reserve from time to time as shall be necessary, proper or desirable to carry into effect the
purpose, obligations under, and intent of the Purchase Agreement. 
 Approval of Actions 

FURTHER RESOLVED, that, without limiting the foregoing, the Authorized Officers are, and each of them hereby is, authorized and directed to
proceed on behalf of the Company and to take all such steps as deemed necessary or appropriate, with the advice and assistance of counsel, to cause the Company to consummate the agreements referred to herein and to perform its obligations under such
agreements; and 

  
 44 

 FURTHER RESOLVED, that the Authorized Officer be, and hereby is, authorized, empowered and
directed on behalf of and in the name of the Company, to take or cause to be taken all such further actions and to execute and deliver or cause to be executed and delivered all such further agreements, amendments, documents, certificates, reports,
schedules, applications, notices, letters and undertakings and to incur and pay all such fees and expenses as in their judgment shall be necessary, proper or desirable to carry into effect the purpose and intent of any and all of the foregoing
resolutions, and that all actions heretofore taken by any officer or director of the Company in connection with the transactions contemplated by the agreements described herein are hereby approved, ratified and confirmed in all respects. 

IN WITNESS WHEREOF, the Board of Directors has executed and delivered this Consent effective as of March [•], 2022. 

 

									
	By:	 	  
	 	            	  	By:	 	  

	Date:	 		 		  	Date:	 	
					
	By:	 	  
	 		  	By:	 	  

	Date:	 		 		  	Date:	 	
					
	By:	 	  
	 		  	By:	 	  

	Date:	 		 		  	Date:	 	
					
	By:	 	  
	 		  		 	
	Date:	 		 		  		 	

  
 45EX-10.6

 Exhibit 10.6 

REGISTRATION RIGHTS AGREEMENT 

THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of March 17, 2022, by and among BROOKLINE
CAPITAL ACQUISITION CORP., a Delaware corporation (the “Company”), APEXIGEN, INC., a Delaware corporation (“Apexigen”), and LINCOLN PARK CAPITAL FUND, LLC, an Illinois limited
liability company (together with it permitted assigns, the “Buyer”). Capitalized terms used herein and not otherwise defined herein shall have the respective meanings set forth in the Purchase Agreement by and among the parties
hereto, dated as of the date hereof (as amended, restated, supplemented or otherwise modified from time to time, the “Purchase Agreement”). 

WHEREAS: 
 Pursuant to
that certain Business Combination Agreement by and among the Company, Apexigen, and Project Barolo Merger Sub Inc., a wholly owned subsidiary of the Company (“Merger Sub”) dated as of March 17, 2022, the Company and Apexigen
intend to effect a merger of Merger Sub with and into Apexigen (the “Merger”) and, upon consummation of the Merger, Merger Sub will cease to exist and Apexigen will become a wholly owned subsidiary of the Company; and 

From and after the Merger, and subject to the terms and conditions set forth in the Purchase Agreement, the Company wishes to sell to the
Investor, and the Investor wishes to buy from the Company, up to Fifty Million Dollars ($50,000,000) of Purchase Shares, and to induce the Buyer to enter into the Purchase Agreement, the Company has agreed to provide certain registration rights
under the Securities Act of 1933, as amended, and the rules and regulations thereunder (collectively, the “Securities Act”), and applicable state securities laws. 

NOW, THEREFORE, in consideration of the promises and the mutual covenants contained herein and other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the Company and the Buyer hereby agree as follows: 
 1. DEFINITIONS.

 As used in this Agreement, the following terms shall have the following meanings: 

(a) “Investor” means the Buyer, any transferee or assignee thereof to whom a Buyer assigns its rights under this Agreement in
accordance with Section 9 and who agrees to become bound by the provisions of this Agreement, and any transferee or assignee thereof to whom a transferee or assignee assigns its rights under this Agreement in accordance with Section 9 and
who agrees to become bound by the provisions of this Agreement. 
 (b) “Person” means any individual or entity including but
not limited to any corporation, a limited liability company, an association, a partnership, an organization, a business, an individual, a governmental or political subdivision thereof or a governmental agency. 

(c) “Register,” “Registered,” and “Registration” refer to a registration effected by
preparing and filing one or more registration statements of the Company in compliance with the Securities Act and pursuant to Rule 415 under the Securities Act or any successor rule providing for offering securities on a continuous basis
(“Rule 415”), and the declaration or ordering of effectiveness of such registration statement(s) by the United States Securities and Exchange Commission (the “SEC”). 

 (d) “Registrable Securities” means all of the Commitment Shares and all of
the Purchase Shares that may, from time to time, be issued or become issuable to the Investor under the Purchase Agreement (without regard to any limitation or restriction on purchases), and any and all shares of capital stock issued or issuable
with respect to the Purchase Shares or the Commitment Shares or the Purchase Agreement as a result of any stock split, stock dividend, recapitalization, exchange or similar event or otherwise, without regard to any limitation on purchases under the
Purchase Agreement. 
 (e) “Registration Statement” means one or more registration statements of the Company covering only
the sale of the Registrable Securities. 
 2. REGISTRATION. 

(a) Mandatory Registration. The Company shall, within thirty (30) days following the date of consummation of the Merger, file with
the SEC an initial Registration Statement covering the maximum number of Registrable Securities as shall be permitted to be included thereon in accordance with applicable SEC rules, regulations and interpretations so as to permit the resale of such
Registrable Securities by the Investor under Rule 415 under the Securities Act at then prevailing market prices (and not fixed prices), as mutually determined by both the Company and the Investor in consultation with their respective legal counsel,
subject to the aggregate number of authorized shares of the Company’s Common Stock then available for issuance in its Certificate of Incorporation and the Exchange Cap (as defined in the Purchase Agreement), provided, however, that the Company
may delay filing or suspend the use of any Registration Statement if the Company determines, upon advice of legal counsel, that in order for the registration statement to not contain a material misstatement or omission, an amendment thereto would be
needed, or if the Company’s Board of Directors, upon advice of legal counsel, reasonably believes that such filing or use could materially affect a bona fide business or financing transaction of the Company or would require premature disclosure
of information that could materially adversely affect the Company. The initial Registration Statement shall register only the Registrable Securities. The Investor and its counsel shall have a reasonable opportunity to review and comment upon such
Registration Statement and any amendment or supplement to such Registration Statement and any related prospectus prior to its filing with the SEC, and the Company shall give due consideration to all such comments. The Investor shall furnish all
information reasonably requested by the Company for inclusion therein. The Company shall use its commercially reasonable efforts to have the Registration Statement and any amendment declared effective by the SEC at the earliest practicable date. The
Company shall use commercially reasonable efforts to keep the Registration Statement effective pursuant to Rule 415 promulgated under the Securities Act and available for the resale by the Investor of all of the Registrable Securities covered
thereby at all times until the earlier of (i) the date on which the Investor shall have resold all the Registrable Securities covered thereby and no Available Amount (as defined in the Purchase Agreement) remains under the Purchase Agreement,
(ii) such Registrable Securities may be sold without Registration pursuant to Rule 144 without limitation as to volume and manner of sale restrictions and no Available Amount remains under the Purchase Agreement, (iii) six months after the
termination of the Purchase Agreement, and (iv) one year after the date on which no Available Amount remains under the Purchase Agreement (the “Registration Period”). The Registration Statement (including any amendments or
supplements thereto and prospectuses contained therein) shall not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein, or necessary to make the statements therein, in light of the
circumstances in which they were made, not misleading. 
 (b) Rule 424 Prospectus. The Company shall, as required by applicable
securities regulations, from time to time file with the SEC, pursuant to Rule 424 promulgated under the Securities Act, the prospectus and prospectus supplements, if any, to be used in connection with sales of the Registrable Securities under the
Registration Statement. The Investor and its counsel shall have a reasonable opportunity to review and comment upon such prospectus prior to its filing with the SEC, and the Company shall give due consideration to all such comments. The Investor
shall use its commercially reasonable efforts to comment upon such prospectus within one (1) Business Day from the date the Investor receives the substantially final pre-filing version of such prospectus.

  
 2 

 (c) Sufficient Number of Shares Registered. In the event the number of shares
available under the Registration Statement is insufficient to cover all of the Registrable Securities, the Company shall amend the Registration Statement or file a new Registration Statement (a “New Registration Statement”), so as
to cover all of such Registrable Securities (subject to the limitations set forth in Section 2(a)) as soon as practicable, but in any event not later than ten (10) Business Days after the necessity therefor arises, subject to any limits
that may be imposed by the SEC pursuant to Rule 415 under the Securities Act. The Company shall use its commercially reasonable efforts to cause such amendment and/or New Registration Statement to become effective as soon as practicable following
the filing thereof. 
 (d) Offering. If the staff of the SEC (the “Staff”) or the SEC seeks to characterize any
offering pursuant to a Registration Statement filed pursuant to this Agreement as constituting an offering of securities that does not permit such Registration Statement to become effective and be used for resales by the Investor under Rule 415 at
then-prevailing market prices (and not fixed prices), or if after the filing of the initial Registration Statement with the SEC pursuant to Section 2(a), the Company is otherwise required by the Staff or the SEC to reduce the number of
Registrable Securities included in such initial Registration Statement, then the Company shall reduce the number of Registrable Securities to be included in such initial Registration Statement (with the prior consent, which shall not be unreasonably
withheld, of the Investor as to the specific Registrable Securities to be removed therefrom) until such time as the Staff and the SEC shall so permit such Registration Statement to become effective and be used as aforesaid. In the event of any
reduction in Registrable Securities pursuant to this paragraph, the Company shall file one or more New Registration Statements in accordance with Section 2(c) until such time as all Registrable Securities have been included in Registration
Statements that have been declared effective and the prospectus contained therein is available for use by the Investor. Notwithstanding any provision herein or in the Purchase Agreement to the contrary, the Company’s obligations to register
Registrable Securities (and any related conditions to the Investor’s obligations) shall be qualified as necessary to comport with any requirement of the SEC or the Staff as addressed in this Section 2(d). 

3. RELATED OBLIGATIONS. 

With respect to the Registration Statement and whenever any Registrable Securities are to be registered pursuant to Section 2 including
on any New Registration Statement, the Company shall use its reasonable best efforts to effect the registration of the Registrable Securities in accordance with the intended method of disposition thereof and, pursuant thereto, the Company shall have
the following obligations: 
 (a) The Company shall prepare and file with the SEC such amendments (including post-effective amendments) and
supplements to any Registration Statement and the prospectus used in connection with such Registration Statement, which prospectus is to be filed pursuant to Rule 424 promulgated under the Securities Act, as may be necessary to keep the Registration
Statement or any New Registration Statement effective at all times during the Registration Period, and, during such period, comply with the provisions of the Securities Act in connection with the offer, issuance and sale of the Registrable
Securities. 
 (b) The Company shall permit the Investor to review and comment upon the final
pre-filing draft version of the Current Report at least two (2) Business Days prior to its filing with the SEC and, with respect to information regarding the Investor or the transaction contemplated
hereby, the Company shall not file the Current Report or the Registration Statement with the SEC in a form to which the Investor reasonably objects. The Investor shall use its reasonable best efforts to comment upon the Registration Statement or any
New Registration Statement and any amendments or supplements thereto within two (2) Business Days from the date the Investor receives the final version thereof. The Company shall furnish to the Investor, without charge any correspondence from the
SEC or the staff of the SEC to the Company or its representatives relating to the Registration Statement or any New Registration Statement. 

  
 3 

 (c) Upon request of the Investor, the Company shall furnish to the Investor,
(i) promptly after the same is prepared and filed with the SEC, at least one copy of such Registration Statement and any amendment(s) thereto, including financial statements and schedules, all documents incorporated therein by reference and all
exhibits, (ii) upon the effectiveness of any Registration Statement, a copy of the prospectus included in such Registration Statement and all amendments and supplements thereto (or such other number of copies as the Investor may reasonably
request) and (iii) such other documents, including copies of any preliminary or final prospectus, as the Investor may reasonably request from time to time in order to facilitate the disposition of the Registrable Securities owned by the
Investor. For the avoidance of doubt, any filing available to the Investor via the SEC’s live EDGAR system shall be deemed “furnished to the Investor” hereunder. 

(d) Upon the request of the Investor, the Company shall use commercially reasonable efforts to (i) register and qualify the resale by the
Investor of the Registrable Securities covered by a Registration Statement under such other securities or “blue sky” laws of such jurisdictions in the United States as the Investor reasonably requests, (ii) prepare and file in those
jurisdictions, such amendments (including post-effective amendments) and supplements to such registrations and qualifications as may be necessary to maintain the effectiveness thereof during the Registration Period, (iii) take such other
actions as may be necessary to maintain such registrations and qualifications in effect at all times during the Registration Period, and (iv) take all other actions reasonably necessary or advisable to qualify the Registrable Securities for
sale in such jurisdictions; provided, however, that the Company shall not be required in connection therewith or as a condition thereto to (x) qualify to do business in any jurisdiction where it would not otherwise be required to qualify but
for this Section 3(d), (y) subject itself to general taxation in any such jurisdiction, or (z) file a general consent to service of process in any such jurisdiction. The Company shall promptly notify the Investor who holds Registrable
Securities of the receipt by the Company of any notification with respect to the suspension of the registration or qualification of any of the Registrable Securities for sale under the securities or “blue sky” laws of any jurisdiction in
the United States or its receipt of actual notice of the initiation or threatening of any proceeding for such purpose. 
 (e) As promptly as
practicable after becoming aware of such event or facts, the Company shall notify the Investor in writing of the happening of any event or existence of such facts as a result of which the prospectus included in any Registration Statement, as then in
effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading (provided
that in no event shall such notice contain any material, non-public information regarding the Company), and promptly prepare a supplement or amendment to such Registration Statement to correct such untrue
statement or omission, and deliver a copy of such supplement or amendment to the Investor (or such other number of copies as the Investor may reasonably request) , provided, however, that the Company may delay filing such supplement or amendment if
the Company’s Board of Directors, upon advice of legal counsel, reasonably believes that such filing or use could materially affect a bona fide business or financing transaction of the Company or would require premature disclosure of
information that could materially adversely affect the Company. The Company shall also promptly notify the Investor in writing (i) when a prospectus or any prospectus supplement or post-effective amendment has been filed, and when a
Registration Statement or any post-effective amendment has become effective (notification of such effectiveness shall be delivered to the Investor by email or facsimile on the same day of such effectiveness and by overnight mail), (ii) of any
request by the SEC for amendments or supplements to any Registration Statement or related prospectus or related information, and (iii) of the Company’s reasonable determination that a post-effective amendment to a Registration Statement
would be appropriate. 

  
 4 

 (f) The Company shall use its commercially reasonable efforts to prevent the issuance of any
stop order or other suspension of effectiveness of any registration statement, or the suspension of the qualification of any Registrable Securities for sale in any jurisdiction and, if such an order or suspension is issued, to obtain the withdrawal
of such order or suspension at the earliest possible moment and to notify the Investor of the issuance of such order and the resolution thereof or its receipt of actual notice of the initiation or threat of any proceeding for such purpose. 

(g) The Company shall (i) cause all the Registrable Securities to be listed on each securities exchange on which securities of the same
class or series issued by the Company are then listed, if any, if the listing of such Registrable Securities is then permitted under the rules of such exchange, or (ii) secure designation and quotation of all the Registrable Securities on the
Principal Market (as defined in the Purchase Agreement). The Company shall pay all fees and expenses in connection with satisfying its obligation under this Section 3. 

(h) The Company shall cooperate with the Investor to facilitate the timely preparation and delivery of certificates (not bearing any
restrictive legend) representing the Registrable Securities to be offered pursuant to any registration statement and enable such certificates to be in such denominations or amounts as the Investor may reasonably request and registered in such names
as the Investor may request. 
 (i) The Company shall at all times provide a transfer agent and registrar with respect to its Common Stock.

 (j) If reasonably requested in writing by the Investor, the Company shall (i) as soon as practicable after receipt of written notice
from the Investor, incorporate in a prospectus supplement or post-effective amendment such information as the Investor reasonably requests be included therein relating to the sale and distribution of Registrable Securities, including, without
limitation, information with respect to the number of Registrable Securities being sold, the purchase price being paid therefor and any other terms of the offering of the Registrable Securities; (ii) make all required filings of such prospectus
supplement or post-effective amendment as soon as practicable upon notification of the matters to be incorporated in such prospectus supplement or post-effective amendment; and (iii) supplement or make amendments to any Registration Statement
or New Registration Statement. 
 (k) The Company shall use its commercially reasonable efforts to cause the Registrable Securities covered
by any Registration Statement to be registered with or approved by such other governmental agencies or authorities as may be necessary to consummate the disposition of such Registrable Securities. 

(l) Within one (1) Business Day after any Registration Statement which includes the Registrable Securities is ordered effective by the
SEC, the Company shall deliver, and shall cause legal counsel for the Company to deliver, to the Transfer Agent for such Registrable Securities (with copies to the Investor) confirmation that such Registration Statement has been declared effective
by the SEC in the form attached hereto as Exhibit A, or such other form acceptable to the Company’s Transfer Agent. Thereafter, if requested by the Investor at any time, the Company shall require its counsel to deliver to the Investor a
written confirmation whether the Registration Statement has been declared effective under the Securities Act and if, to its knowledge, whether a stop order suspending the effectiveness of the Registration Statement has been issued or threatened by
the SEC. 
 (m) The Company shall take all other reasonable actions necessary to expedite and facilitate disposition by the Investor of
Registrable Securities pursuant to any Registration Statement. 

  
 5 

 4. OBLIGATIONS OF THE INVESTOR. 

(a) The Company shall notify the Investor in writing of the information the Company reasonably requires from the Investor in connection with
any Registration Statement hereunder. The Investor shall as soon as practicable furnish to the Company such information regarding itself, the Registrable Securities held by it and the intended method of disposition of the Registrable Securities held
by it as shall be reasonably required to effect the registration of such Registrable Securities and shall execute such documents in connection with such registration as the Company may reasonably request. 

(b) The Investor agrees to cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of
any Registration Statement hereunder and any amendments and supplements thereto. 
 (c) The Investor agrees that, upon receipt of any notice
from the Company of the happening of any event or existence of facts of the kind described in Section 3(f) or the first sentence of Section 3(e), the Investor will immediately discontinue disposition of Registrable Securities pursuant to
any Registration Statement(s) covering such Registrable Securities until the Investor’s receipt of the copies a notice regarding the resolution or withdrawal of the stop order or suspension as contemplated by Section 3(f) or of the
supplemented or amended prospectus contemplated by Section 3(f) or the first sentence of 3(e). Notwithstanding anything to the contrary, the Company shall cause its Transfer Agent to promptly deliver shares of Common Stock without any
restrictive legend in accordance with the terms of the Purchase Agreement in connection with any sale of Registrable Securities with respect to which an Investor has entered into a contract for sale prior to the Investor’s receipt of a notice
from the Company of the happening of any event of the kind described in Section 3(f) or the first sentence of Section 3(e) and for which the Investor has not yet settled. 

5. EXPENSES OF REGISTRATION. 

All reasonable expenses (other than sales or brokerage commissions and fees incurred in connection with its sale of the Registrable Securities,
including the fees and disbursement of counsel for the Investor) incurred in connection with registrations, filings or qualifications pursuant to Sections 2 and 3, including, without limitation, all registration, listing and qualifications fees,
printers and accounting fees, and fees and disbursements of counsel for the Company, shall be paid by the Company. 
 6.
INDEMNIFICATION. 
 (a) To the fullest extent permitted by law, the Company will, and hereby does, indemnify, hold harmless and defend
the Investor, each Person, if any, who controls the Investor, the members, the directors, officers, partners, employees, agents, members, managers representatives of the Investor and each Person, if any, who controls the Investor within the meaning
of the Securities Act or the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (each, an “Indemnified Person”), against any losses, claims, damages, liabilities, judgments, fines, penalties, charges,
costs, attorneys’ fees, amounts paid in settlement or expenses, joint or several, (collectively, “Claims”) incurred in investigating, preparing or defending any action, claim, suit, inquiry, proceeding, investigation or appeal
taken from the foregoing by or before any court or governmental, administrative or other regulatory agency, body or the SEC, whether pending or threatened, whether or not an indemnified party is or may be a party thereto (“Indemnified
Damages”), to which any of them may become subject insofar as such Claims (or actions or proceedings, whether commenced or threatened, in respect thereof) arise out of or are based upon: (i) any untrue statement or alleged untrue
statement of a material fact in the Registration Statement, any New Registration Statement or any post-effective amendment thereto, or the omission or alleged omission to state a material fact required to be stated therein or necessary to make the
statements therein not misleading, 

  
 6 

 
(ii) any untrue statement or alleged untrue statement of a material fact contained in the final prospectus (as amended or supplemented, if the Company files any amendment thereof or supplement
thereto with the SEC) or the omission or alleged omission to state therein any material fact necessary to make the statements made therein, in light of the circumstances under which the statements therein were made, not misleading, (iii) any
violation or alleged violation by the Company of the Securities Act, the Exchange Act, any other law, including, without limitation, any state securities law, or any rule or regulation thereunder relating to the offer or sale of the Registrable
Securities pursuant to the Registration Statement or any New Registration Statement or (iv) any material violation by the Company of this Agreement (the matters in the foregoing clauses (i) through (iv) being, collectively,
“Violations”). The Company shall reimburse each Indemnified Person promptly as such expenses are incurred and are due and payable, for any reasonable documented and
out-of-pocket legal fees or other reasonable expenses incurred by them in connection with investigating or defending any such Claim. Notwithstanding anything to the
contrary contained herein, the indemnification agreement contained in this Section 6(a): (i) shall not apply to a Claim by an Indemnified Person arising out of or based upon a Violation which occurs in reliance upon and in conformity with
information about the Investor furnished in writing to the Company by any Indemnified Person expressly for use in connection with the preparation of the Registration Statement, any New Registration Statement or any such amendment thereof or
supplement thereto or prospectus contained therein, if such Registration Statement, New Registration Statement or amendment thereof or supplement thereto or prospectus contained therein was timely made available by the Company pursuant to
Section 3(c) or Section 3(e); (ii) with respect to any superseded prospectus, shall not inure to the benefit of any Indemnified Person from whom the Indemnified Person asserting any such Claim purchased the Registrable Securities that are
the subject thereof (or to the benefit of any Indemnified Person controlling such Indemnified Person) if the untrue statement or omission of material fact contained in the superseded prospectus was corrected in the revised prospectus, as then
amended or supplemented, if such revised prospectus was timely made available by the Company pursuant to Section 3(c) or Section 3(e), and the Indemnified Person was promptly advised in writing not to use the incorrect prospectus prior to
the use giving rise to a violation and such Indemnified Person, notwithstanding such advice, used it; (iii) shall not be available to the extent such Claim is based on a failure of the Investor to deliver or to cause to be delivered the
prospectus made available by the Company, if such prospectus was timely made available by the Company pursuant to Section 3(c) or Section 3(e); and (iv) shall not apply to amounts paid in settlement of any Claim if such settlement is
effected without the prior written consent of the Company, which consent shall not be unreasonably withheld. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of the Indemnified Person and
shall survive the transfer of the Registrable Securities by the Investor pursuant to Section 9. 
 (b) In connection with the
Registration Statement or any New Registration Statement, the Investor agrees to indemnify, hold harmless and defend, to the same extent and in the same manner as is set forth in Section 6(a), the Company, each of its directors, each of its
officers who signs the Registration Statement or any New Registration Statement, each Person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act (collectively and together with an Indemnified Person, an
“Indemnified Party”), against any Claim or Indemnified Damages to which any of them may become subject, under the Securities Act, the Exchange Act or otherwise, insofar as such Claim or Indemnified Damages arise out of or are based
upon any Violation (which, in the case of this Section 6(b) shall include the failure on the part of the Investor to deliver a prospectus as required by this Agreement and applicable law), in each case to the extent, and only to the extent,
that such Violation occurs in reliance upon and in conformity with written information about the Investor set forth on Exhibit B attached hereto and furnished to the Company by the Investor expressly for use in connection with such
Registration Statement (it being hereby acknowledged and agreed that such written information, as the same may be updated from time to time in writing by the Investor, is the only written information furnished to the Company by or on behalf of the
Investor expressly for use in any Registration Statement); and, subject to Section 6(d), the Investor will reimburse any reasonable documented and out-of-pocket
legal or other expenses reasonably incurred 

  
 7 

 
by them in connection with investigating or defending any such Claim; provided, however, that the indemnity agreement contained in this Section 6(b) and the agreement with respect to
contribution contained in Section 7 shall not apply to amounts paid in settlement of any Claim if such settlement is effected without the prior written consent of the Investor, which consent shall not be unreasonably withheld; provided,
further, however, that the Investor shall be liable under this Section 6(b) for only that amount of a Claim or Indemnified Damages as does not exceed the net proceeds to the Investor as a result of the sale of Registrable Securities pursuant to
such Registration Statement. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of such Indemnified Party and shall survive the transfer of the Registrable Securities by the Investor pursuant to
Section 9. 
 (c) Promptly after receipt by an Indemnified Person or Indemnified Party under this Section 6 of notice of the
commencement of any action or proceeding (including any governmental action or proceeding) involving a Claim, such Indemnified Person or Indemnified Party shall, if a Claim in respect thereof is to be made against any indemnifying party under this
Section 6, deliver to the indemnifying party a written notice of the commencement thereof, and the indemnifying party shall have the right to participate in, and, to the extent the indemnifying party so desires, jointly with any other
indemnifying party similarly noticed, to assume control of the defense thereof with counsel mutually satisfactory to the indemnifying party and the Indemnified Person or the Indemnified Party, as the case may be; provided, however, that an
Indemnified Person or Indemnified Party shall have the right to retain its own counsel with the fees and expenses to be paid by the indemnifying party, if, in the reasonable opinion of counsel retained by the indemnifying party, the representation
by such counsel of the Indemnified Person or Indemnified Party and the indemnifying party would be inappropriate due to actual or potential differing interests between such Indemnified Person or Indemnified Party and any other party represented by
such counsel in such proceeding. 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 with respect to such claim, unless in the reasonable judgment, with advice of counsel, 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. The Indemnified Party or Indemnified Person shall cooperate fully with the indemnifying party in connection with any negotiation or defense of any such action or claim by the indemnifying party and shall furnish to the
indemnifying party all information reasonably available to the Indemnified Party or Indemnified Person which relates to such action or claim. The indemnifying party shall keep the Indemnified Party or Indemnified Person fully apprised at all times
as to the status of the defense or any settlement negotiations with respect thereto. No indemnifying party shall be liable for any settlement of any action, claim or proceeding effected without its written consent, provided, however, that the
indemnifying party shall not unreasonably withhold, delay or condition its consent. No indemnifying party shall, without the consent of the Indemnified Party or Indemnified Person, consent to entry of any judgment or enter into any settlement or
other compromise which does not include as an unconditional term thereof the giving by the claimant or plaintiff to such Indemnified Party or Indemnified Person of a release from all liability in respect to such claim or litigation. Following
indemnification as provided for hereunder, the indemnifying party shall be subrogated to all rights of the Indemnified Party or Indemnified Person with respect to all third parties, firms or corporations relating to the matter for which
indemnification has been made. The failure to deliver written notice to the indemnifying party within a reasonable time of the commencement of any such action shall not relieve such indemnifying party of any liability to the Indemnified Person or
Indemnified Party under this Section 6, except to the extent that the indemnifying party is prejudiced in its ability to defend such action. 

(d) The indemnification required by this Section 6 shall be made by periodic payments of the amount thereof during the course of the
investigation or defense, as and when bills are received or Indemnified Damages are incurred. 

  
 8 

 (e) The indemnity agreements contained herein shall be in addition to (i) any cause of
action or similar right of the Indemnified Party or Indemnified Person against the indemnifying party or others, and (ii) any liabilities the indemnifying party may be subject to pursuant to law. 

7. CONTRIBUTION. 
 To the
extent any indemnification by an indemnifying party is prohibited or limited by law, the indemnifying party agrees to make the maximum contribution with respect to any amounts for which it would otherwise be liable under Section 6 to the
fullest extent permitted by law; provided, however, that: (i) no seller of Registrable Securities guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any
seller of Registrable Securities who was not guilty of fraudulent misrepresentation; and (ii) contribution by any seller of Registrable Securities shall be limited in amount to the net amount of proceeds received by such seller from the sale of
such Registrable Securities. 
 8. REPORTS AND DISCLOSURE UNDER THE SECURITIES ACTS. 

With a view to making available to the Investor the benefits of Rule 144 promulgated under the Securities Act or any other similar rule or
regulation of the SEC that may at any time permit the Investor to sell securities of the Company to the public without registration (“Rule 144”), the Company agrees, at the Company’s sole expense, to: 

(a) make and keep public information available, as those terms are understood and defined in Rule 144; 

(b) file with the SEC in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act
so long as the Company remains subject to such requirements and the filing of such reports and other documents is required for the applicable provisions of Rule 144; 

(c) furnish to the Investor so long as the Investor owns Registrable Securities, promptly upon reasonable request, (i) a written statement
by the Company that it has complied with the reporting and or disclosure provisions of Rule 144, the Securities Act and the Exchange Act, (ii) a copy of the most recent annual or quarterly report of the Company and such other reports and
documents so filed by the Company, and (iii) such other information as may be reasonably requested to permit the Investor to sell such securities pursuant to Rule 144 without registration; and 

(d) take such additional action as is reasonably requested by the Investor to enable the Investor to sell the Registrable Securities pursuant
to Rule 144, including, without limitation, delivering all such legal opinions, consents, certificates, resolutions and instructions to the Company’s Transfer Agent as may be reasonably requested from time to time by the Investor and otherwise
fully cooperate with Investor and Investor’s broker to effect such sale of securities pursuant to Rule 144; provided, however, the Investor and its broker shall cooperate with the Company and its counsel and provide the necessary certificates,
instructions and other documents reasonably requested by the Company or its counsel in order to enable the Investor to sell the Registrable Securities pursuant to Rule 144. 

The Company agrees that damages may be an inadequate remedy for any breach of the terms and provisions of this Section 8 and that
Investor shall, whether or not it is pursuing any remedies at law, be entitled to seek equitable relief in the form of a preliminary or permanent injunction, without having to post any bond or other security, upon any breach or threatened breach of
any such terms or provisions. 

  
 9 

 9. ASSIGNMENT OF REGISTRATION RIGHTS. 

The Company shall not assign this Agreement or any rights or obligations hereunder without the prior written consent of the Investor;
provided, however, that any transaction, whether by merger, reorganization, restructuring, consolidation, financing or otherwise, whereby the Company remains the surviving entity immediately after such transaction shall not be deemed an assignment.
The Investor may not assign its rights under this Agreement without the written consent of the Company, other than to an affiliate of the Investor controlled by Jonathan Cope or Josh Scheinfeld, in which case the assignee must agree in writing to be
bound by the terms and conditions of this Agreement. 
 10. AMENDMENT OF REGISTRATION RIGHTS. 

No provision of this Agreement may be amended or waived by the parties from and after the date that is one (1) Business Day immediately
preceding the initial filing of the Registration Statement with the SEC. Subject to the immediately preceding sentence, no provision of this Agreement may be (i) amended other than by a written instrument signed by both parties hereto or
(ii) waived other than in a written instrument signed by the party against whom enforcement of such waiver is sought. Failure of any party to exercise any right or remedy under this Agreement or otherwise, or delay by a party in exercising such
right or remedy, shall not operate as a waiver thereof. 
 11. MISCELLANEOUS. 

(a) A Person is deemed to be a holder of Registrable Securities whenever such Person owns or is deemed to own of record such Registrable
Securities. If the Company receives conflicting instructions, notices or elections from two or more Persons with respect to the same Registrable Securities, the Company shall act upon the basis of instructions, notice or election received from the
registered owner of such Registrable Securities. 
 (b) Any notices, consents, waivers or other communications required or permitted to be
given under the terms of this Agreement must be in writing and will be deemed to have been delivered: (i) upon receipt, when delivered personally; (ii) upon receipt, when sent by facsimile or email (provided confirmation of transmission is
mechanically or electronically generated and kept on file by the sending party); or (iii) one (1) Business Day after deposit with a nationally recognized overnight delivery service, in each case properly addressed to the party to receive the
same. The addresses for such communications shall be: 
 If to the Company: 

 

			
	Brookline Capital Acquisition Corp.
	280 Park Avenue, Suite 43W
	New York, NY 10017
	Phone:	  	646-603-6716
	Attention:	  	Samuel P. Wertheimer, Chairman and CEO
	Email:	  	***

 With a copy to (which shall not constitute notice or service of process): 

 

			
	DLA Piper LLP (US)
	1251 Avenue of the Americas
	New York, NY 10020
	Attention:	  	 James Kelly; Peter Ekberg

  
 10 

 
			
	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 Apexigen: 

 

			
	Apexigen, Inc.
	75 Shoreway Rd., Suite C
	San Carlos, CA 94070
	Phone:	  	650-931-6236
	Attention:	  	Xiaodong Yang, MD, PhD, President and CEO; Francis Sarena, Chief Operating Officer
	Email:	  	***

 With a copy to: 

 

			
	 Wilson Sonsini
 650 Mill Page
Road

	Palo Alto, CA 94304
	Phone:	  	650-493-9300
	Attention:	  	Kenneth A. Clark; Michael E. Coke; Lance E. Brady
	Email:	  	kclark@wsgr.com; mcoke@wsgr.com; lbrady@wsgr.com

 If to the Investor: 

 

			
	Lincoln Park Capital Fund, LLC
	440 North Wells, Suite 410
	Chicago, IL 60654
	Telephone:	  	312.822.9300
	Facsimile:	  	312.822.9301
	E-mail:	  	***
	Attention:	  	Josh Scheinfeld/Jonathan Cope

 With a copy to (which shall not constitute notice or service of process): 

 

			
	 K&L Gates, LLP
 200 S. Biscayne
Blvd., Ste. 3900

	Miami, Florida 33131
	Telephone:	  	305.539.3306
	Facsimile:	  	305.358.7095
	E-mail:	  	clayton.parker@klgates.com
	Attention:	  	Clayton E. Parker, Esq.

 If to the Transfer Agent: 

 

			
	Continental Stock Transfer & Trust
	1 State Street 30th Floor
	New York, NY 10004-1561
	Attention:	  	Douglas Reed
	E-mail:	  	***

  
 11 

 or at such other address, email address and/or facsimile number and/or to the attention of such other person
as the recipient party has specified by written notice given to each other party three (3) Business Days prior to the effectiveness of such change. Written confirmation of receipt (A) given by the recipient of such notice, consent, waiver
or other communication, (B) mechanically or electronically generated by the sender’s facsimile machine or email account containing the time, date, recipient facsimile number or email address, as applicable, or (C) provided by a
nationally recognized overnight delivery service, shall be rebuttable evidence of personal service, receipt by facsimile, email or receipt from a nationally recognized overnight delivery service in accordance with clause (i), (ii) or
(iii) above, respectively. 
 (c) The corporate laws of the State of Delaware shall govern all issues concerning the relative rights of
the Company and its stockholders. All other questions concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by the internal laws of the State of New York, without giving effect to any choice of law
or conflict of law provision or rule (whether of the State of New York or any other jurisdictions) that would cause the application of the laws of any jurisdictions other than the State of New York. Each party hereby irrevocably submits to the
exclusive jurisdiction of the state and federal courts sitting the State of New York, Borough of Manhattan, for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and
hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is brought in an inconvenient forum or
that the venue of such suit, action or proceeding is improper. Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof to such party at
the address for such notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process
in any manner permitted by law. If any provision of this Agreement shall be invalid or unenforceable in any jurisdiction, such invalidity or unenforceability shall not affect the validity or enforceability of the remainder of this Agreement in that
jurisdiction or the validity or enforceability of any provision of this Agreement in any other jurisdiction. EACH PARTY HEREBY IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE, AND AGREES NOT TO REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE
HEREUNDER OR IN CONNECTION HEREWITH OR ARISING OUT OF THIS AGREEMENT OR ANY TRANSACTION CONTEMPLATED HEREBY. 
 (d) This Agreement and
the Purchase Agreement constitute the entire agreement among the parties hereto with respect to the subject matter hereof and thereof. There are no restrictions, promises, warranties or undertakings among the parties hereto, other than those set
forth or referred to herein and therein. This Agreement and the Purchase Agreement supersede all prior agreements and understandings among the parties hereto with respect to the subject matter hereof and thereof. 

(e) This Agreement is intended for the benefit of the parties hereto and any permitted successors and assigns and, except as set forth in
Section 9, is not for the benefit of, nor may any provision hereof be enforced by, any other Person. 

  
 12 

 (f) The headings in this Agreement are for convenience of reference only and shall not limit
or otherwise affect the meaning hereof. 
 (g) This Agreement may be executed in identical counterparts, each of which shall be deemed an
original but all of which shall constitute one and the same agreement. This Agreement, once executed by a party, may be delivered to the other party hereto by facsimile transmission or by e-mail in a
“.pdf” format data file of a copy of this Agreement bearing the signature of the party so delivering this Agreement. 
 (h) Each
party shall do and perform, or cause to be done and performed, all such further acts and things, and shall execute and deliver all such other agreements, certificates, instruments and documents, as the other party may reasonably request in order to
carry out the intent and accomplish the purposes of this Agreement and the consummation of the transactions contemplated hereby. 
 (i) The
language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent and no rules of strict construction will be applied against any party. 

(j) This Agreement is intended for the benefit of the parties hereto and their respective successors and permitted assigns, and is not for the
benefit of, nor may any provision hereof be enforced by, any other Person. 
 * * * * * * 

IN WITNESS WHEREOF, the parties have caused this Registration Rights Agreement to be duly executed as of day and year first above
written. 
  

			
	THE COMPANY:
	
	BROOKLINE CAPITAL ACQUISITION CORP.
		
	By:	 	 /s/ Dr. Samuel P. Wertheimer

	Name:	 	Dr. Samuel P. Wertheimer
	Title:	 	Chief Executive Officer and Chairman
	
	APEXIGEN:
	
	APEXIGEN, INC.
		
	By:	 	 /s/ Xiaodong Yang

	Name:	 	Xiaodong Yang
	Title:	 	Chief Executive Officer

  
 13 

 
			
	THE INVESTOR:
	
	LINCOLN PARK CAPITAL FUND, LLC
	BY:	 	LINCOLN PARK CAPITAL, LLC
	BY:	 	ROCKLEDGE CAPITAL CORPORATION
		
	By:	 	 /s/ Josh Scheinfeld

	Name:	 	Josh Scheinfeld
	Title:	 	President

  
 14 

 EXHIBIT A 

TO REGISTRATION RIGHTS AGREEMENT 

FORM OF NOTICE OF EFFECTIVENESS 

OF REGISTRATION STATEMENT 
 [Date] 

[TRANSFER AGENT] 

                         
              

                         
              
 Re: [__________] 

Ladies and Gentlemen: 
 We are counsel to
Brookline Capital Acquisition Corp., a Delaware corporation (the “Company”), and have represented the Company in connection with that certain Purchase Agreement, dated as of [___________], 2022 (the “Purchase
Agreement”), entered into by and between the Company and Lincoln Park Capital Fund, LLC (the “Buyer”) pursuant to which, among other things, the Company has agreed to issue to the Buyer shares of the Company’s Common
Stock, par value $0.0001 per share (the “Common Stock”), in an amount up to Fifty Million Dollars ($50,000,000) (the “Purchase Shares”), in accordance with the terms of the Purchase Agreement. In connection with the
transactions contemplated by the Purchase Agreement, the Company has registered with the U.S. Securities and Exchange Commission (the “SEC”) [__________] shares of Common Stock that may be issued and sold by the Company to
the Buyer from time to time (the “Purchase Shares”), 150,000 shares of Common Stock as Commitment Shares (the “Initial Commitment Shares”) and $1,500,000 worth of Common Stock as Additional Commitment Shares
(the “Additional Commitment Shares” and, collectively with the Initial Commitment Shares, the “Commitment Shares”). 

Pursuant to the Purchase Agreement, the Company also has entered into a Registration Rights Agreement, dated as of [____________], 2022 with
the Buyer (the “Registration Rights Agreement”) pursuant to which the Company agreed, among other things, to register the Purchase Shares and the Commitment Shares under the Securities Act of 1933, as amended (the
“Securities Act”). In connection with the Company’s obligations under the Purchase Agreement and the Registration Rights Agreement, on [_____________], 2022, the Company filed a Registration Statement (File No. 333-[_________]) (the “Registration Statement”) with the SEC relating to the resale of the Purchase Shares and the Commitment Shares by the Buyer. 

In connection with the foregoing, we advise you that a member of the SEC’s staff has advised us by telephone that the SEC has entered an
order declaring the Registration Statement effective under the Securities Act at __:__ am/pm on _______ __, 2022, and we have no knowledge, based solely on our review of the SEC’s “Stop Orders” web page
(http://sec.gov/litigation/stoporders.shtml), that any stop order suspending the Registration Statement’s effectiveness has been issued or that any proceedings for that purpose are pending before, or threatened by, the SEC. 

 

			
	Very truly yours,
	
	[Company Counsel]
		
	By:	 	  

  

	cc:	 Lincoln Park Capital Fund, LLC 

 EXHIBIT B 

TO REGISTRATION RIGHTS AGREEMENT 

Information About The Investor Furnished To The Company By The Investor 

Expressly For Use In Connection With The Registration Statement 

Information With Respect to Lincoln Park Capital 
 As of
the date of the Purchase Agreement, Lincoln Park Capital Fund, LLC, beneficially owned [•] shares of our common stock. Josh Scheinfeld and Jonathan Cope, the Managing Members of Lincoln Park Capital, LLC, the manager of Lincoln Park Capital
Fund, LLC, are deemed to be beneficial owners of all of the shares of common stock owned by Lincoln Park Capital Fund, LLC. Messrs. Cope and Scheinfeld have shared voting and investment power over the shares being offered under the prospectus filed
with the SEC in connection with the transactions contemplated under the Purchase Agreement. Lincoln Park Capital, LLC is not a licensed broker dealer or an affiliate of a licensed broker dealer.

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