EX-10.2





 Exhibit 10.2 

REGISTRATION RIGHTS AGREEMENT 

THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of July 20, 2020, is entered into
by and between HISTOGEN INC., a Delaware corporation (the “Company”), and LINCOLN PARK CAPITAL FUND, LLC, an Illinois limited liability company (together with its permitted assigns, the “Investor”).
Capitalized terms used herein and not otherwise defined herein shall have the respective meanings set forth in the Purchase Agreement by and between the parties hereto, dated as of the date hereof (as amended, restated, supplemented or otherwise
modified from time to time, the “Purchase Agreement”). 
 WHEREAS: 

A. Upon the terms and subject to the conditions of the Purchase Agreement, (i) the Company has agreed to issue to the
Investor, and the Investor has agreed to purchase, up to Ten Million Dollars ($10,000,000) of the Company’s common stock, par value $0.0001 per share (the “Common Stock”), pursuant to the Purchase Agreement (such shares, the
“Purchase Shares”), and (ii) the Company has agreed to issue to the Investor such number of shares of Common Stock as is required pursuant to the Purchase Agreement (the “Commitment Shares”); and 

B. To induce the Investor 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, or any similar successor statute (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 Investor hereby agree as follows: 
  

	 	1.	 DEFINITIONS. 



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

(a) “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 SEC. 

(b) “Registrable Securities” means the Purchase Shares that may from time to time be issued or issuable to
the Investor upon purchases of the Available Amount under the Purchase Agreement (without regard to any limitation or restriction on purchases), the Commitment Shares issued or issuable to the Investor, and any Common Stock issued or issuable with
respect to the Purchase Shares, the Commitment Shares or the Purchase Agreement as a result of any stock split, stock dividend, recapitalization, exchange or similar event, without regard to any limitation on purchases under the Purchase
Agreement. 
 (c) “Registration Statement” means the Shelf Registration Statement and any other
registration statement of the Company that Registers Registrable Securities, including a New Registration Statement, as amended when each became effective, including all documents filed as part thereof or incorporated by reference therein, and
including any information contained in a Prospectus subsequently filed with the SEC. 












 (d) “Shelf Registration Statement” means the Company’s
existing registration statement on Form S-3 (File No. 333- 220014). 
  

	 	2.	 REGISTRATION. 



(a) Mandatory Registration. The Company agrees that it shall, within the time required under Rule 424(b) under the
Securities Act, file with the SEC the Initial Prospectus Supplement pursuant to Rule 424(b) under the Securities Act specifically relating to the transactions contemplated by, and describing the material terms and conditions of, the Transaction
Documents, containing information previously omitted at the time of effectiveness of the Registration Statement in reliance on Rule 430B under the Securities Act, and disclosing all information relating to the transactions contemplated hereby
required to be disclosed in the Registration Statement and the Prospectus as of the date of the Initial Prospectus Supplement, including, without limitation, information required to be disclosed in the section captioned “Plan of
Distribution” in the Prospectus. The Investor acknowledges that it will be identified in the Initial Prospectus Supplement as an underwriter within the meaning of Section 2(a)(11) of the Securities Act. The Company shall permit the
Investor to review and comment upon the Initial Prospectus Supplement at least two (2) Business Days prior to its filing with the SEC, the Company shall give due consideration to all such comments, and the Company shall not file the Initial
Prospectus Supplement with the SEC in a form to which the Investor reasonably objects. The Investor shall use its reasonable best efforts to comment upon the Initial Prospectus Supplement within one (1) Business Day from the date the Investor
receives a substantially complete draft thereof from the Company. The Investor shall furnish to the Company such information regarding itself, the Securities held by it and the intended method of distribution thereof, including any arrangement
between the Investor and any other Person relating to the sale or distribution of the Securities, as shall be reasonably requested by the Company in connection with the preparation and filing of the Initial Prospectus Supplement, and shall otherwise
cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of the Initial Prospectus Supplement with the SEC. 

(b) Effectiveness. The Company shall use its commercially reasonable efforts to keep the Registration Statement
effective pursuant to Rule 415 promulgated under the Securities Act, and to keep the Registration Statement and the Prospectus current and available for issuances and sales of all possible Registrable Securities by the Company to the Investor, and
for the resale of all of the Registrable Securities by the Investor, at all times until the earlier of (i) the date on which the Investor shall have sold all the Securities and no Available Amount remains under this Agreement and (ii) 180 days
following the earlier of termination of this Agreement and the Maturity Date (the “Registration Period”). Without limiting the generality of the foregoing, during the Registration Period, the Company shall (a) take all action
necessary to cause the Common Stock to continue to be Registered as a class of securities under Section 12(b) of the Exchange Act and shall not take any action or file any document (whether or not permitted by the Exchange Act) to terminate or
suspend such registration and (b) file or furnish on or before their respective due dates all reports and other documents required to be filed or furnished by the Company pursuant to Sections 13(a), 13(c), 14, 15(d) or any other provision of or
under the Exchange Act, and shall not take any action or file any document (whether or not permitted by the Exchange Act) to terminate or suspend its reporting and filing obligations under the Exchange Act. 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 necessary to make the statements therein, in the light of the circumstances under which
they were made, not misleading. 

  
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 (c) Prospectus Amendments or Supplements. Except as provided in this
Agreement and other than periodic and current reports required to be filed pursuant to the Exchange Act, the Company shall not file with the SEC any amendment to the Registration Statement or any supplement to the Base Prospectus that refers to the
Investor, the Transaction Documents or the transactions contemplated thereby (including, without limitation, any Prospectus Supplement filed in connection with the transactions contemplated by the Transaction Documents), in each case with respect to
which (a) the Investor shall not previously have been advised and afforded the opportunity to review and comment thereon at least two (2) Business Days prior to filing with the SEC, as the case may be, (b) the Company shall not have
given due consideration to any comments thereon received from the Investor or its counsel, or (c) the Investor shall reasonably object, unless the Company reasonably has determined that it is necessary to amend the Registration Statement or
make any supplement to the Prospectus to comply with the Securities Act or any other applicable law or regulation, in which case the Company shall promptly (but in no event later than 24 hours) so inform the Investor, the Investor shall be provided
with a reasonable opportunity to review and comment upon any disclosure referring to the Investor, the Transaction Documents or the transactions contemplated thereby, as applicable, and the Company shall expeditiously furnish to the Investor a copy
thereof. In addition, for so long as, in the reasonable opinion of counsel for the Investor, the Prospectus is required to be delivered in connection with any acquisition or sale of Securities by the Investor, the Company shall not file any
Prospectus Supplement with respect to the Securities without furnishing to the Investor as many copies of such Prospectus Supplement, together with the Prospectus, as the Investor may reasonably request. 

(d) Sufficient Number of Shares Registered. In the event the number of shares available under the Shelf Registration
Statement at any time is insufficient to cover the Registrable Securities, the Company shall, to the extent necessary and permissible, amend the Shelf Registration Statement or file a new registration statement (together with any prospectuses or
prospectus supplements thereunder, a “New Registration Statement”), so as to cover all of such Registrable Securities as soon as reasonably practicable, but in any event not later than ten (10) Business Days after the necessity
therefor arises. The Company shall use its reasonable commercial efforts to have such amendment and/or New Registration Statement become effective as soon as reasonably practicable following the filing thereof. 

(e) Offering. If 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 by the Investor under Rule 415 at then-prevailing market prices (and not fixed prices), or if after the filing of
the Initial Prospectus Supplement 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 and its legal counsel as to the
specific Registrable Securities to be removed therefrom) until such time as 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(d) until such time as all Registrable Securities have been included in Registration Statements that have been declared
effective and the prospectuses contained therein is available for use by the Investor. 
  

	 	3.	 RELATED OBLIGATIONS. 



With respect to the Registration Statement and whenever any Registrable Securities are to be Registered pursuant to
Section 2, including on the Shelf Registration Statement or on any New Registration Statement, the Company shall use its commercially reasonable efforts to effect the 

  
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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) Notifications. The Company will notify the Investor promptly of the time when any subsequent amendment to the Shelf
Registration Statement or any New Registration Statement, other than documents incorporated by reference, has been filed with the SEC and/or has become effective or where a receipt has been issued therefor or any subsequent supplement to a
Prospectus has been filed and of any request by the SEC for any amendment or supplement to the Registration Statement, any New Registration Statement or any Prospectus or for additional information. 

(b) Amendments. The Company will prepare and file with the SEC, promptly upon the Investor’s request, any
amendments or supplements to the Shelf Registration Statement, any New Registration Statement or any Prospectus, as applicable, that, in the reasonable opinion of the Investor and the Company, may be necessary or advisable in connection with any
acquisition or sale of Registrable Securities by the Investor (provided, however, that the failure of the Investor to make such request shall not relieve the Company of any obligation or liability hereunder). 

(c) Investor Review. The Company will not file any amendment or supplement to the Registration Statement, any New
Registration Statement or any Prospectus, other than documents incorporated by reference, relating to the Investor, the Registrable Securities or the transactions contemplated hereby unless (A) the Investor shall have been advised and afforded
the opportunity to review and comment thereon at least two (2) Business Days prior to filing with the SEC, (B) the Company shall have given due consideration to any comments thereon received from the Investor or its counsel, and
(C) the Investor has not reasonably objected thereto (provided, however, that the failure of the Investor to make such objection shall not relieve the Company of any obligation or liability hereunder), and the Company will furnish to the
Investor at the time of filing thereof a copy of any document that upon filing is deemed to be incorporated by reference into the Registration Statement or any Prospectus, except for those documents available via EDGAR. 

(d) Form S-3. The Company will cause each amendment or supplement to the
Prospectus, other than documents incorporated by reference, to be filed with the SEC as required pursuant to the rules of Form S-3. 

(e) Copies Available. The Company will furnish to the Investor and its counsel (at the expense of the Company) copies
of the Registration Statement, the Prospectus (including all documents incorporated by reference therein), any Prospectus Supplement, any New Registration Statement and all amendments and supplements to the Registration Statement, the Prospectus or
any New Registration Statement that are filed with the SEC during the Registration Period (including all documents filed with or furnished to the SEC during such period that are deemed to be incorporated by reference therein), in each case as soon
as reasonably practicable upon the Investor’s request and in such quantities as the Investor may from time to time reasonably request and, at the Investor’s request, will also furnish copies of the Prospectus to each exchange or market on
which sales of the Registrable Securities may be made; provided, however, that the Company shall not be required to furnish any document (other than the Prospectus) to the Investor to the extent such document is available on EDGAR. 

(f) Qualification. The Company shall take all such action, if any, as is reasonably necessary in order to obtain an
exemption for or to 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 

  
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during the Registration Period, and shall provide evidence of any such action so taken to the Investor. During the Registration Period, the Company shall promptly notify the Investor 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 threat of any proceeding for such purpose. 
 (g) Notification of
Stop Orders; Material Changes. The Company shall advise the Investor promptly (but in no event later than 24 hours) and shall confirm such advice in writing, in each case: (i) of the Company’s receipt of notice of any request by the
SEC or any other federal or state governmental authority for amendment of or a supplement to the Registration Statement or any Prospectus or for any additional information; (ii) of the Company’s receipt of notice of the issuance by the SEC
or any other federal or state governmental authority of any stop order suspending the effectiveness of the Registration Statement or prohibiting or suspending the use of the Prospectus or Prospectus Supplement, or any New Registration Statement, or
of the Company’s receipt of any notification of the suspension of qualification of the Registrable Securities for offering or sale in any jurisdiction or the initiation or contemplated initiation of any proceeding for such purpose; and
(iii) of the Company becoming aware of the happening of any event, which makes any statement of a material fact made in the Registration Statement or any Prospectus untrue or which requires the making of any additions to or changes to the
statements then made in the Registration Statement or any Prospectus in order to state a material fact required by the Securities Act to be stated therein or necessary in order to make the statements then made therein (in the case of any Prospectus,
in light of the circumstances under which they were made) not misleading, or of the necessity to amend the Registration Statement or any Prospectus to comply with the Securities Act or any other law. The Company shall not be required to disclose to
the Investor the substance or specific reasons of any of the events set forth in clauses (i) through (iii) of the immediately preceding sentence, but rather, shall only be required to disclose that the event has occurred. If at any time the
SEC, or any other federal or state governmental authority shall issue any stop order suspending the effectiveness of the Registration Statement or prohibiting or suspending the use of the Prospectus or Prospectus Supplement, the Company shall use
its reasonable commercial efforts to obtain the withdrawal of such order at the earliest practicable time. The Company shall furnish to the Investor, without charge, a copy of any correspondence from the SEC or the staff of the SEC, or any other
federal or state governmental authority to the Company or its representatives relating to the Shelf Registration Statement, any New Registration Statement or any Prospectus, or Prospectus Supplement as the case may be. The Company shall not deliver
to the Investor any Regular Purchase Notice, Accelerated Purchase Notice or Additional Accelerated Purchase Notice, and the Investor shall not be obligated to purchase any shares of Common Stock under this Agreement, during the continuation or
pendency of any of the foregoing events. If at any time the SEC shall issue any stop order suspending the effectiveness of the Registration Statement or prohibiting or suspending the use of the Prospectus or any Prospectus Supplement, the Company
shall use its reasonable commercial efforts to obtain the withdrawal of such order at the earliest practicable time. The Company shall furnish to the Investor, without charge, a copy of any correspondence from the SEC or the staff of the SEC to the
Company or its representatives relating to the Registration Statement or the Prospectus, as the case may be. 
 (h)
Listing on the Principal Market. The Company shall promptly secure the listing, or conditional listing as applicable, of all of the Purchase Shares and Commitment Shares to be issued to the Investor hereunder on the Principal Market (subject
to standard listing conditions, if any, for transactions of this nature, official notice of issuance and the Exchange Cap) and upon each other national securities exchange or automated quotation system, if any, upon which the Common Stock are then
listed, and shall maintain, so long as any Common Stock shall be so listed, such listing of all such Registrable 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 

  
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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 provide the Investor copies of any such notice that the Company reasonably believes constitutes
material non-public information and that the Company would not be required to publicly disclose such notice in any report or statement filed with the SEC under the Exchange Act (including on Form 8-K) or the Securities Act. The Company shall pay all fees and expenses in connection with satisfying its obligations under this Section 3(h). 

(i) Delivery of Shares. The Company shall cooperate with the Investor to facilitate the timely preparation and delivery
of DWAC Shares (not bearing any restrictive legend) representing the Registrable Securities to be offered pursuant to the Shelf Registration Statement or any New Registration Statement and enable such DWAC Shares to be in such denominations or
amounts as the Investor may reasonably request and registered in such names as the Investor may request. 
 (j) Transfer
Agent. The Company shall at all times during the term of this Agreement maintain the services of the Transfer Agent with respect to its Common Stock. 

(k) Approvals. The Company shall use its reasonable commercial efforts to cause the Registrable Securities covered by
any Registration Statement to be Registered with or approved by such other governmental agencies or authorities in the United States as may be necessary to consummate the disposition of such Registrable Securities. 

(l) Confirmation of Effectiveness. If reasonably requested by the Investor at any time, the Company shall deliver to
the Investor a written confirmation from Company’s counsel of whether or not the effectiveness of such Registration Statement has lapsed at any time for any reason (including, without limitation, the issuance of a stop order) and whether or not
the Registration Statement is currently effective and available to the Company for sale of all of the Registrable Securities. 

(m) Further Assurances. The Company agrees to take all other reasonable actions as necessary and reasonably requested
by the Investor to expedite and facilitate disposition by the Investor of Registrable Securities pursuant to any Registration Statement. 

(n) Suspension of Sales. The Investor agrees that, upon receipt of any notice from the Company of the existence of any
suspension or stop order as set forth in Section 3(f) or 3(g), the Investor will immediately discontinue disposition of Registrable Securities pursuant to any Registration Statement covering such Registrable
Securities until the Investor’s receipt of the copies of a notice regarding the resolution or withdrawal of the suspension or stop order as contemplated by Section 3(f) or 3(g). Notwithstanding anything to the
contrary, the Company shall cause its transfer agent to promptly deliver to the Investor DWAC Shares 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 the 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 3(g) and for
which the Investor has not yet settled. 
 (o) Transfer Agent Instructions. On or before the date the Registration
Statement and any New Registration Statement is declared effective by the SEC, the Company shall issue to the Transfer Agent the Irrevocable Transfer Agent Instructions in the form agreed to prior to the date hereof, and on the date any Registration
Statement which includes the Registrable Securities is ordered effective 

  
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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 as an exhibit to the Commencement Irrevocable Transfer Agent Instructions. Thereafter, if requested by the Investor at any time, the Company shall require
its legal counsel to deliver to the Investor a written confirmation whether or not the effectiveness of such Registration Statement has lapsed at any time for any reason (including, without limitation, the issuance of a stop order) and whether or
not the Registration Statement is current and available to the Investor for sale of all of the Registrable Securities. 
  

	 	4.	 OBLIGATIONS OF THE INVESTOR. 



(a) Investor Information. The Investor has furnished to the Company in Exhibit A hereto such information
regarding itself, the Registrable Securities held by it, the Registrable Securities held by it and the intended method of disposition thereof, including any arrangement between the Investor and any other Person relating to the sale or distribution
of the Securities, as 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. The Company shall notify the Investor in writing of
any other information the Company reasonably requires from the Investor in connection with any Registration Statement hereunder. The Investor will as promptly as practicable notify the Company of any material change in the information set forth in
Exhibit A, other than changes in its ownership of Common Stock. 
 (b) Investor Cooperation. The Investor
agrees to cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of any amendments and supplements to any Registration Statement or New Registration Statement hereunder. 

 

	 	5.	 EXPENSES OF REGISTRATION. 



All reasonable expenses of the Company, other than sales or brokerage commissions and fees and disbursements of counsel for,
and other expenses of, 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. Investor shall bear and be responsible for all expenses of Investor in connection with its review of any of the registrations, filings or
qualifications pursuant to this Agreement. 
  

	 	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, members, managers, agents, representatives of the Investor and each Person, if any, who controls the Investor within the meaning of
the Securities Act or the Exchange Act (each, an “Indemnified Person”), against any losses, claims, damages, liabilities, judgments, fines, penalties, charges, costs, reasonable attorneys’ fees, amounts paid in settlement (with
the consent of the Company, such consent not to be unreasonably withheld) or reasonable expenses, (collectively, “Claims”) reasonably 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 or 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 

  
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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 Shelf Registration Statement, any
New Registration Statement or any post-effective amendment thereto or in any filing made in connection with the qualification of the offering under the securities or other “blue sky” laws of any jurisdiction in which Registrable Securities
are offered (“Blue Sky Filing”), 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, (ii) any untrue statement or alleged untrue
statement of a material fact contained in the final Prospectus 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 Shelf 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”). Subject to Section 6(d), the Company shall reimburse each Indemnified Person promptly as such expenses are incurred and are due and payable, for any
reasonable 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): (A) 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 furnished in writing to the Company by the Investor or such Indemnified Person expressly for use in connection with the preparation of the Registration Statement, any New Registration Statement, the Prospectus or
any such amendment thereof or supplement thereto, if such in each case if the foregoing was timely made available by the Company; (B) with respect to any superseded prospectus, shall not inure to the benefit of any such Person from whom the
Person asserting any such Claim purchased the Registrable Securities that are the subject thereof (or to the benefit of any other 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; (C) 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 theretofore made available by the Company pursuant to Section 3(c) or Section 3(e); and (D) 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 8. 

(b) In connection with the Shelf Registration Statement, any New Registration Statement or Prospectus, 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 signed the Shelf Registration Statement or
signs 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, 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 A attached hereto or updated from time to time in writing by the Investor and
furnished to the Company by the Investor expressly for inclusion in the Shelf Registration Statement or Prospectus or any New Registration 

  
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Statement or from the 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, subject to Section 6(d), the Investor will reimburse any reasonable out-of-pocket legal or other expenses reasonably incurred 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 8. 

(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. The Indemnified Party or Indemnified Person shall cooperate 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 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. Any Person receiving a payment pursuant to this Section  

  
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6 which person is later determined to not be entitled to such payment shall return such payment to the person making it. 

(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 the 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.	 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 prior 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. 
  

	 	9.	 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 Business Day
immediately preceding the initial filing of the Initial Prospectus Supplement 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. 
  

	 	10.	 MISCELLANEOUS. 



(a) 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 (provided confirmation of transmission is mechanically or electronically
generated and kept on file by the sending party); (iii) upon receipt, when sent by electronic message (provided the recipient responds to the message and confirmation of both electronic messages are kept on file by the sending party); or
(iv) one (1) Business Day after timely deposit with a nationally recognized overnight delivery service, in each case properly addressed to the party to receive the same. The addresses and facsimile numbers for such communications shall be: 


  
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		 	 Histogen Inc.

		 	 10655 Sorrento Valley Road, Suite 200

		 	 San Diego, CA 92121

		 	 Telephone:
	  	
858-526-3100

		 	 E-mail:
	  	
		 	 Attention:
	  	 Susan A. Knudson


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

 

					
		 	 DLA Piper LLP (US)

		 	 4365 Executive Drive, Suite 100

		 	 San Diego, CA 92130

		 	 Telephone:
	  	
858-677-1414

		 	 Facsimile:
	  	
858-638-5014

		 	 E-mail:
	  	 larry.nishnick@us.dlapiper.com

		 	 Attention:
	  	 Larry W. Nishnick


 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:
	  	 jscheinfeld@lpcfunds.com/jcope@lpcfunds.com

		 	 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.


 or at such other address, e-mail 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 at least one (1) Business Day 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 containing the time, date, and recipient facsimile number,
(C) electronically generated by the sender’s electronic mail containing the time, date and recipient email address or (D) provided by a nationally recognized overnight delivery service, shall be rebuttable evidence of receipt in
accordance with clause (i), (ii), (iii) or (iv) above, respectively. Any party to this Agreement may give any notice or other communication hereunder using any other means (including messenger service, ordinary mail or electronic mail), but no
such notice or other communication shall be deemed to have been duly given unless it actually is received by the party for whom it is intended. 

  
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 (b) No Waiver 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. 

(c) Governing Law. All questions concerning the construction, validity, enforcement and interpretation of this
Agreement shall be governed by the internal laws of the State of Illinois, without giving effect to any choice of law or conflict of law provision or rule (whether of the State of Illinois or any other jurisdictions) that would cause the application
of the laws of any jurisdictions other than the State of Illinois. Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in the County of Cook, in the State of Illinois 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) Integration. This Agreement, the Purchase Agreement and the other Transaction Documents constitute the
entire understanding among the parties hereto with respect to the subject matter hereof and thereof. There are no restrictions, promises, warranties or undertakings, other than those set forth or referred to herein and therein. This
Agreement, the Purchase Agreement and the other 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 hereof and thereof. 
 (e) No Third Party Benefits. Subject to the requirements of
Section 8, this Agreement shall inure to the benefit of and be binding upon the permitted successors and assigns of each of the parties hereto. 

(f) Headings. The headings in this Agreement are for convenience of reference and shall not form part of, or affect the
interpretation of, this Agreement. 
 (g) 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 or pdf (or other electronic
reproduction of a) signature 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, not a facsimile or pdf (or other electronic reproduction of a)
signature. 

  
 12 













 (h) 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 carry out the intent and accomplish the
purposes of this Agreement and the consummation of the transactions contemplated hereby. 
 (i) 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. 

(j) 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. 
 * * * *
* * 

  
 13 













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

			
	THE COMPANY:
	
	HISTOGEN INC.
		
	 By:
	 	 /s/ Richard Pascoe

	 Name:
	 	 Richard W. Pascoe

	 Title:
	 	 Chief Executive Officer & President




 

			
	INVESTOR:
	
	LINCOLN PARK CAPITAL FUND, LLC
	BY: LINCOLN PARK CAPITAL, LLC
	BY Rockledge Capital Corporation
		
	By:	 	/s/ Joshua Scheinfeld
	Name:	 	Joshua Scheinfeld
	Title:	 	President



  
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 EXHIBIT A 

Information About The Investor Furnished To The Company By The Investor 

Expressly For Use In Connection With Each Registration Statement and Prospectus 

Information With Respect to Lincoln Park Capital 

Immediately prior to the date of the Purchase Agreement, Lincoln Park Capital Fund, LLC, beneficially owned 0 shares of
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 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 supplement 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.