Exhibit 10.6


 


UNIT SUBSCRIPTION AGREEMENT


 


This UNIT SUBSCRIPTION AGREEMENT (this “Agreement”)
is made as of this 17th day of May 2017, by and between Constellation Alpha Capital Corp., a British Virgin Islands business
company (the “Company”), having its principal place of business at Emerald View, Suite 400, 2054 Vista
Parkway, West Palm Beach, FL 33411, and Cowen Investments LLC (the “Purchaser”).


 


WHEREAS, the Company desires to sell on a
private placement basis (the “Offering”) an aggregate of 100,000 units (the “Private Units”)
of the Company, each Private Unit comprised of one ordinary share of the Company, no par value per share (the “Ordinary
Shares”), one right to receive one-tenth (1/10) of one share of common stock (the “Right”),
and one warrant (the “Warrant”) to purchase one-half of one Ordinary Share (the “Warrant
Shares”), for an aggregate purchase price of $1,000,000, or $10.00 per Private Unit;


 


WHEREAS, simultaneously with the consummation
of the Company’s initial public offering (“IPO”) of 12,500,000 units (the “Public Units”)
consisting of Ordinary Shares, the Rights and Warrants, the Company proposes to sell on a private placement basis to Centripetal,
LLC (the “Sponsor”), and the Sponsor proposes to purchase from the Company, an aggregate of 280,000 units
(or 317,500 units if the over-allotment option is exercised in full) (the “Founder Units”) that are identical
to the Private Units for a purchase price of $2,800,000 (or $3,175,000 if the over-allotment option is exercised in full), or $10.00
per Founder Unit;


 


WHEREAS, concurrently with the issuance of
the Private Units, the Company agrees to issue to the Purchaser 100,000 Ordinary Shares (the "Private Shares")
for no additional consideration, which Ordinary Shares shall be identical to the Ordinary Shares (the "Founder Shares")
purchased by the Sponsor prior to the Company’s IPO and, in connection therewith, the Sponsor shall forfeit by surrendering
without consideration to the Company 100,000 Founder Shares; and


 


WHEREAS, the Purchaser desires to purchase
the Private Units and the Company wishes to accept such subscription.


 


NOW, THEREFORE, in consideration of the promises
and the mutual covenants hereinafter set forth and other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the Company and the Purchaser hereby agree as follows:


 


1. Agreement to
Subscribe


 


1.1. Purchase and Issuance of the Private
Units; Issuance of Private Shares. For the aggregate sum of $1,000,000 (the “Purchase Price”), or
$10.00 per Private Unit, upon the terms and subject to the conditions of this Agreement, the Purchaser hereby agrees to purchase
from the Company, and the Company hereby agrees to sell to the Purchaser, on the Closing Date (as defined in Section 1.2) 100,000
Private Units, free and clear of any and all liens, claims, options, charges, pledges, security interests, voting agreements, voting
trusts, encumbrances, or restrictions of any nature (“Liens”) (other than restrictions under applicable
securities laws and the restrictions contained herein). Concurrently with the purchase of the Private Units by the Purchaser, the
Company agrees to issue to the Purchaser 100,000 Ordinary Shares, free and clear of any and all Liens (other than restrictions
under applicable securities laws and the restrictions contained herein).


  


1.2. Closing. The closing (the “Closing”)
of the subscription of the Private Units and the issuance of the Private Shares shall take place at the offices of Ellenoff Grossman
& Schole LLP, 1345 Avenue of the Americas, New York, New York, 10105 simultaneously with the consummation of the Company’s
IPO (such date, the “Closing Date”).


 




    		1	 



     


    

 


1.3. Delivery of the Purchase Price.
On the Closing Date, the Purchaser agrees to deliver the Purchase Price by certified bank check or wire transfer of immediately
available funds denominated in United States Dollars to Continental Stock Transfer & Trust Company, which funds shall be deposited
on the Closing Date to the trust account established for the benefit of the Company’s public shareholders, managed pursuant
to that certain Investment Management Trust Agreement to be entered into by and between the Company and Continental Stock Transfer
& Trust Company, as trustee, and into which substantially all of the proceeds of the IPO will be deposited (the “Trust
Account”). For the avoidance of doubt, if the size of the IPO is reduced after the date hereof, this Agreement shall
become null and void and be of no further force and effect.


 


1.4. Delivery of Securities; Forfeiture
of Founder Shares. Upon the Closing Date after delivery of the Purchase Price in accordance with Section 1.3, the Company shall
(ii) issue to the Purchaser, and the Purchaser shall become irrevocably entitled to receive, a unit certificate representing the
Private Units purchased hereunder and a certificate representing the Private Shares, and (ii) cause the forfeiture by the Sponsor
of 100,000 Founder Shares.  In furtherance of the foregoing, the Company shall register the Purchaser as the owner of the
Private Units and the Private Shares in the register of members of the Company and with the Company’s transfer agent by book
entry on or promptly after the Closing Date.


 


1.5 Closing Conditions.


 


(a)   The obligation of the Purchaser to
purchase the Private Units at the Closing under this Agreement shall be subject to the fulfillment, at or prior to the Closing
of each of the following conditions, any of which, to the extent permitted by applicable laws, may be waived by the Purchaser:


 


(i)   The representations and warranties
of the Company set forth in Section 3 of this Agreement shall have been true and correct as of the date hereof and shall be true
and correct as of the Closing, with the same effect as though such representations and warranties had been made on and as of such
date (other than any such representation or warranty that is made by its terms as of a specified date, which shall be true and
correct as of such specified date), except where the failure to be so true and correct would not have a material adverse effect
on the Company or its ability to consummate the transactions contemplated by this Agreement;


 


(ii)   The Company shall have performed,
satisfied and complied in all material respects with the covenants, agreements and conditions required by this Agreement to be
performed, satisfied or complied with by the Company or the Sponsor at or prior to the Closing;


 


(iii)   No order, writ, judgment, injunction,
decree, determination, or award shall have been entered by or with any governmental, regulatory, or administrative authority or
any court, tribunal, or judicial, or arbitral body, and no other legal restraint or prohibition shall be in effect, preventing
the purchase by the Purchaser of the Securities.


 


(iv)   The Company shall have duly executed
and delivered the Underwriting Agreement relating to the IPO.


 


(v)   The Sponsor shall have forfeited by
surrendering without consideration to the Company 100,000 Founder Shares.


 




    		2	 



     


    

 


(vi)   The Company shall have furnished opinions
of Ellenoff Grossman & Schole LLP, counsel for the Company, and Ogier, British Virgin Islands counsel for the Company, each
addressed to the Purchaser, and dated the Closing Date, and each in form and substance satisfactory to the Purchaser.


 


(b)   The obligation of the Company to sell
the Private Units at the Closing under this Agreement shall be subject to the fulfillment, at or prior to the Closing of each of
the following conditions, any of which, to the extent permitted by applicable laws, may be waived by the Company;


 


(i)   The representations and warranties
of the Purchaser set forth in Section 2 of this Agreement shall have been true and correct as of the date hereof and shall be true
and correct as of the Closing, with the same effect as though such representations and warranties had been made on and as of such
date (other than any such representation or warranty that is made by its terms as of a specified date, which shall be true and
correct as of such specified date), except where the failure to be so true and correct would not have a material adverse effect
on the Purchaser or its ability to consummate the transactions contemplated by this Agreement;


 


(ii)   The Purchaser shall have performed,
satisfied and complied in all material respects with the covenants, agreements and conditions required by this Agreement to be
performed, satisfied or complied with by the Purchaser at or prior to the Closing; and


 


(iii)   No order, writ, judgment, injunction,
decree, determination, or award shall have been entered by or with any governmental, regulatory, or administrative authority or
any court, tribunal, or judicial, or arbitral body, and no other legal restraint or prohibition shall be in effect, preventing
the purchase by the Purchaser of the Private Units.


 


2. Representations and Warranties of
the Purchaser


 


The Purchaser represents and warrants to
the Company that:


 


2.1.   No Government Recommendation or
Approval. It understands that no United States federal or state agency or similar agency of any other country has passed upon
or made any recommendation or endorsement of the Company, the Private Units, the Rights, the Warrants, or Warrant Shares, the Ordinary
Shares underlying the Private Units or the Ordinary Shares issuable upon conversion of the Rights (excluding the Warrant Shares,
the “Private Unit Shares” and, collectively with the Private Units and Warrant Shares, the “Securities”)
or the Private Shares.


 


2.2.   Organization.  It is a
limited liability company, validly existing and in good standing under the laws of its jurisdiction and possesses all requisite
power and authority necessary to carry out the transactions contemplated by this Agreement.


 


2.3.   Private Offering. It is an
“accredited investor” as such term is defined in Rule 501(a) of Regulation D under the Securities Act of 1933, as amended
(the “Securities Act”). It acknowledges that the sale contemplated hereby is being made in reliance on
a private placement exemption to “accredited investors” within the meaning of Section 501(a) of Regulation D under
the Securities Act and similar exemptions under state law.


 


2.4.   Authority. This Agreement has
been validly authorized, executed and delivered by the Purchaser and is a valid and binding agreement enforceable in accordance
with its terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, fraudulent conveyance or similar
laws affecting the enforcement of creditors’ rights generally and subject to general principles of equity (regardless of
whether enforcement is sought in a proceeding at law or in equity).


 




    		3	 



     


    

 


2.5.   No Conflicts. The execution,
delivery and performance of this Agreement and the consummation by the Purchaser of the transactions contemplated hereby do not
violate, conflict with or constitute a default under (i)  the Purchaser’s organizational documents, (ii) any agreement,
indenture or instrument to which the Purchaser is a party or (iii) any law, statute, rule or regulation to which the Purchaser
is subject, or any agreement, order, judgment or decree to which the Purchaser is subject.


 


2.6.   No Legal Advice from Company.
It acknowledges it has had the opportunity to review this Agreement and the transactions contemplated by this Agreement and the
other agreements entered into between the parties hereto with its own legal counsel and investment and tax advisors. Except for
any statements or representations of the Company made in this Agreement and the other agreements entered into between the parties
hereto, it is relying solely on such counsel and advisors and not on any statements or representations of the Company or any of
its representatives or agents for legal, tax or investment advice with respect to this investment, the transactions contemplated
by this Agreement or the securities laws of any jurisdiction.


 


2.7.   Access to Information; Independent
Investigation. Prior to the execution of this Agreement, it has had the opportunity to ask questions of and receive answers
from representatives of the Company concerning an investment in the Company, as well as the finances, operations, business and
prospects of the Company, and the opportunity to obtain additional information to verify the accuracy of all information so obtained.
In determining whether to make this investment, it has relied solely on its own knowledge and understanding of the Company and
its business based upon its own due diligence investigation and the information furnished pursuant to this paragraph. It understands
that no person has been authorized to give any information or to make any representations which were not furnished pursuant to
this Section 2 and it has not relied on any other representations or information in making its investment decision, whether written
or oral, relating to the Company, its operations and/or its prospects.


 


2.8.   Reliance on Representations and
Warranties. It understands the Private Units are being offered and sold to it in reliance on exemptions from the registration
requirements under the Securities Act, and analogous provisions in the laws and regulations of various states, and that the Company
is relying upon the truth and accuracy of the representations, warranties, agreements, acknowledgments and understandings of the
Purchaser set forth in this Agreement in order to determine the applicability of such provisions.


 


2.9.   No Advertisements. It is not
subscribing for the Private Units as a result of or subsequent to any advertisement, article, notice or other communication published
in any newspaper, magazine, or similar media or broadcast over television or radio, or presented at any seminar or meeting.


 


2.10.   Legend. It acknowledges and
agrees the certificates (if any) evidencing (i) the Private Units and the Ordinary Shares, the Rights and Warrants underlying the
Private Units and (ii) the Private Shares shall bear a restrictive legend (the “Legend”), in form and
substance as set forth in Section 4.1 hereof, prohibiting the offer, sale, pledge or transfer of the securities, except (1) pursuant
to an effective registration statement covering these securities under the Securities Act or (2) pursuant to any other exemptions
from the registration requirements under the Securities Act and such laws which, in the opinion of counsel for the Company, is
available.


 




    		4	 



     


    

 


2.11.   Experience, Financial Capability
and Suitability. It is (i) sophisticated in financial matters and is able to evaluate the risks and benefits of the investment
in the Securities and the Private Shares and (ii) able to bear the economic risk of its investment in the Securities and the Private
Shares for an indefinite period of time because the Securities and the Private Shares have not been registered under the Securities
Act and therefore cannot be sold unless subsequently registered under the Securities Act or an exemption from such registration
is available. It has substantial experience in evaluating and investing in transactions of securities in companies similar to the
Company so that it is capable of evaluating the merits and risks of its investment in the Company and has the capacity to protect
its own interests.  


 


2.12.   Investment Purposes. It is
acquiring the Securities and the Private Shares solely for investment purposes, for its own account and not for the account or
benefit of any other person, and not with a view towards the distribution or dissemination thereof and it has no present arrangement
to sell the interest in the Securities or the Private Shares to or through any person or entity.


 


2.13.   Restrictions on Transfer.
It acknowledges and understands the Private Units and the Private Shares are being offered in a transaction not involving a public
offering in the United States within the meaning of the Securities Act. The Securities and the Private Shares have not been registered
under the Securities Act, and, if in the future, it decides to offer, resell, pledge or otherwise transfer the Securities or the
Private Shares, such Securities or such Private Shares, as applicable, may be offered, resold, pledged or otherwise transferred
only (A) pursuant to an effective registration statement filed under the Securities Act, (B) pursuant to an exemption
from registration under Rule 144 promulgated under the Securities Act (“Rule 144”), if available, or
(C) pursuant to any other available exemption from the registration requirements of the Securities Act, and in each case in
accordance with any applicable securities laws of any state or any other jurisdiction. It agrees that if any transfer of its Securities
or Private Shares or any interest therein is proposed to be made, as a condition precedent to any such transfer, it may be required
to deliver to the Company an opinion of counsel satisfactory to the Company. Absent registration or another available exemption
from registration, it agrees it will not resell the Securities or the Private Shares. It further acknowledges that because the
Company is a shell company, Rule 144 may not be available to it for the resale of the Securities or the Private Shares until the
one year anniversary following consummation of the initial Business Combination (defined below) of the Company, despite technical
compliance with the requirements of Rule 144 and the release or waiver of any contractual transfer restrictions.


 


3. Representations and Warranties of
the Company


 


The Company represents and warrants to
the Purchaser that:


 


3.1.   Valid Issuance of Share Capital.
The total number of all classes of share capital which the Company has authority to issue is (i) an unlimited number of Ordinary
Shares and (ii) an unlimited number of preferred shares. As of the date hereof, the Company has issued 4,312,500 Ordinary Shares
(of which 662,500 Ordinary Shares are subject to forfeiture as described in the registration statement related to the IPO), and
no preferred shares issued and outstanding. All of the issued share capital of the Company has been duly authorized, validly issued,
and are fully paid and non-assessable.


 


3.2.  Title to Securities. Upon issuance
in accordance with, and payment pursuant to, the terms hereof, the warrant agreement to be entered into with a mutually agreeable
warrant agent on or prior to the closing of the IPO (“Warrant Agreement”) and the rights agreement to
be entered into with a mutually agreeable rights agent on or prior to the closing of the IPO (the “Rights Agreement”),
as the case may be, each of the Warrants, the Rights, the Ordinary Shares and the Private Shares will be duly and validly issued,
fully paid and non-assessable, free and clear of any Liens (other than restrictions under applicable securities laws and the restrictions
contained herein). On the date of issuance of the Private Units, the Warrant Shares shall have been reserved for issuance. Upon
issuance in accordance with the terms hereof and the Warrant Agreement, the Purchaser will have or receive good title to the Warrant
Shares, free and clear of any and all Liens (other than restrictions under applicable securities laws and the restrictions contained
herein). Upon issuance in accordance with the terms hereof and the Rights Agreement, the Purchaser will have or receive good title
to the Ordinary Shares issuable upon conversion of the Rights, free and clear of any and all Liens (other than restrictions under
applicable securities laws and the restrictions contained herein).


 




    		5	 



     


    

 


3.3.  Organization and Qualification.
The Company has been duly incorporated and is validly existing as a British Virgin Islands business company and has the requisite
corporate power to own its properties and assets and to carry on its business as now being conducted.


 


3.4.  Authorization; Enforcement.
(i) The Company has the requisite corporate power and authority to enter into and perform its obligations under this Agreement
and to issue the Securities in accordance with the terms hereof, (ii) the execution, delivery and performance of this Agreement
by the Company and the consummation by it of the transactions contemplated hereby have been duly authorized by all necessary corporate
action and no further consent or authorization of the Company or its Board of Directors or shareholders is required, and (iii) this
Agreement constitutes, and upon the execution and delivery thereof, each of the Rights, the Rights Agreement, the Warrants and
the Warrant Agreement will constitute, valid and binding obligations of the Company enforceable against the Company in accordance
with their respective terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, fraudulent conveyance,
moratorium, reorganization, or similar laws relating to, or affecting generally the enforcement of, creditors’ rights and
remedies or by equitable principles of general application and except as enforcement of rights to indemnity and contribution may
be limited by federal and state securities laws or principles of public policy.


 


3.5.  No Conflicts. The execution,
delivery and performance of this Agreement and the consummation by the Company of the transactions contemplated hereby do not (i) result
in a violation of the Company’s Memorandum and Articles of Association, (ii) conflict with, or constitute a default
under any agreement, indenture or instrument to which the Company is a party or (iii) conflict with any law statute, rule or regulation
to which the Company is subject or any agreement, order, judgment or decree to which the Company is subject. Other than any federal,
state or foreign securities filings which may be required to be made by the Company subsequent to the Closing, and any registration
statement which may be filed pursuant thereto, the Company is not required under federal, state or local law, rule or regulation
to obtain any consent, authorization or order of, or make any filing or registration with, any court or governmental agency or
self-regulatory entity in order for it to perform any of its obligations under this Agreement or issue (1) the Private Units, the
Rights, the Warrants or the Ordinary Shares underlying the Private Units, the Rights or Warrants or (2) the Private Shares, in
each case, in accordance with the terms hereof.


 


3.6.  Operations. As of the date
hereof, the Company has not conducted, and prior to the IPO Closing the Company will not conduct, any operations other than organizational
activities and activities in connection with offerings of the Securities.


 


3.7  Foreign Corrupt Practices. Neither
the Company, nor any director, officer, agent, employee or other Person acting on behalf of the Company has, in the course of its
actions for, or on behalf of, the Company (i) used any corporate funds for any unlawful contribution, gift, entertainment or other
unlawful expenses relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic
government official or employee from corporate funds; (iii) violated or is in violation of any provision of the U.S. Foreign Corrupt
Practices Act of 1977, as amended; or (iv) made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful
payment to any foreign or domestic government official or employee.


 




    		6	 



     


    

 


3.8  Compliance with Anti-Money Laundering
Laws. The operations of the Company are and have been conducted at all times in compliance with applicable financial recordkeeping
and reporting requirements and all other applicable U.S. and non-U.S. anti-money laundering laws and regulations, including, but
not limited to, those of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the USA Patriot Act of 2001 and
the applicable money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related
or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Anti-Money
Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or
body or any arbitrator involving the Company with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of
the Company, threatened.


 


3.9  Absence of Litigation. There
is no action, suit, proceeding, inquiry or investigation before or by any court, public board, government agency, self-regulatory
organization or body pending or, to the knowledge of the Company, threatened against or affecting the Company or any of the Company’s
officers or directors, whether of a civil or criminal nature or otherwise, in their capacities as such.


 


3.10  Choice of Law. The Company
has the power to submit, legally, validly, effectively and irrevocably, to the jurisdiction of any state courts in the State of
New York or the United States District Court for the Southern District of New York.


 


4. Legends


 


4.1.  Legend. The Company will issue
(i) the Private Units, the Rights, the Warrants and the Private Unit Shares, and when issued, the Warrant Shares and the Ordinary
Shares issuable upon conversion of the Rights, purchased by the Purchaser, and (ii) the Private Shares, in each case, in the name
of the Purchaser. Each register and book entry for each of the Securities and the Private Shares shall contain a notation, and
each certificate (if any) evidencing the Securities and the Private Shares shall be stamped or otherwise imprinted with a legend,
in substantially the following form


 


THESE SECURITIES (i) HAVE NOT
BEEN REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND THESE SECURITIES
MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT (A) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT FILED UNDER
THE SECURITIES ACT, (B) PURSUANT TO AN EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE)
OR (C) PURSUANT TO ANY OTHER EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT, IN EACH CASE IN ACCORDANCE WITH
ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES OR ANY OTHER JURISDICTION. HEDGING TRANSACTIONS INVOLVING THESE
SECURITIES MAY NOT BE CONDUCTED UNLESS IN COMPLIANCE WITH THE SECURITIES ACT.


 


“THE SECURITIES REPRESENTED
BY THIS CERTIFICATE ARE SUBJECT TO AN AGREEMENT BETWEEN CONSTELLATION ALPHA CAPITAL CORP. AND COWEN INVESTMENTS LLC AND MAY ONLY
BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR OTHERWISE DISPOSED DURING THE TERM OF THE LOCKUP PURSUANT TO THE TERMS SET FORTH THEREIN.”


 




    		7	 



     


    

 


4.2.  Purchaser’s Compliance.
Nothing in this Section 4 shall affect in any way the Purchaser’s obligations and agreements to comply with all applicable
securities laws upon resale of the Securities.


 


4.3.  Company’s Refusal to Register
Transfer of the Securities and the Private Shares. The Company shall refuse to register any transfer of the Securities or the
Private Shares, if in the reasonable judgment of the Company such purported transfer would not be made (i) pursuant to an
effective registration statement filed under the Securities Act, or (ii) pursuant to an available exemption from the registration
requirements of the Securities Act.


 


4.4.  Registration Rights. The Purchaser
will be entitled to certain registration rights which will be governed by a registration rights agreement (“Registration
Rights Agreement”) to be entered into with the Company on or prior to the closing of the IPO; provided, however,
that the Purchaser may not exercise its demand and “piggy back” registration rights pursuant to such Registration Rights
Agreement after five (5) and seven (7) years after the effective date of the Registration Statement, respectively, and the Purchaser
may not exercise its demand registration rights thereunder more than one time.


 


4.5  Removal of Legend. Following
the expiration of the transfer restrictions set forth herein, if any of the Securities or the Private Shares are eligible to be
sold without restriction under, and without the Company being in compliance with the current public information requirements of,
Rule 144 under the Securities Act, then at the Purchaser’s request, the Company will cause the Company’s transfer agent
to remove the legend set forth in Section 4.1. In connection therewith, if required by the Company’s transfer agent, the
Company will promptly cause an opinion of counsel to be delivered to and maintained with its transfer agent, together with any
other authorizations, certificates and directions required by the transfer agent that authorize and direct the transfer agent to
issue such Securities without any such legend.


 


5.  Transfer Restrictions


 


5.1   FINRA Lock-up. The Purchaser
acknowledges and agrees that the Private Units, the Warrants, the Private Unit Shares and the Warrant Shares shall not be transferable,
saleable or assignable until after the consummation of an acquisition, share exchange, purchase of all or substantially all of
the assets of, or any other similar business combination with one or more businesses or entities (a “Business Combination”),
except to permitted transferees. The Private Units, the Rights, the Warrants, the Private Unit Shares, the Warrant Shares, the
Ordinary Shares issuable upon conversion of the Rights, and the Private Shares will be deemed compensation by the Financial Industry
Regulatory Authority (“FINRA”) and will therefore be subject to lock-up for a period of 180 days immediately
following the date of effectiveness of the Registration Statement or commencement of sales of the IPO, subject to certain limited
exceptions, pursuant to Rule 5110(g)(1) of the FINRA Manual. Accordingly, the Private Units, the Rights, the Warrants, the Private
Unit Shares, the Warrant Shares, the Ordinary Shares issuable upon conversion of the Rights, and the Private Shares may not be
sold, transferred, assigned, pledged or hypothecated for 180 days immediately following the effective date of the Registration
Statement except to any underwriter or selected dealer participating in the IPO and the bona fide officers or partners of the Purchaser
and any such participating underwriter or selected dealer nor may they be the subject of any hedging, short sale, derivative, put
or call transaction that would result in the economic disposition of the securities by any person during such 180-day period.


 




    		8	 



     


    

 


5.2   Transfer Restrictions.


 


(i)   Subject to Section 5.1, the Purchaser
shall not Transfer (as defined below) any Private Shares until, with respect to 50% of the Private Shares, the earlier of (1) one
year after the consummation of a Business Combination or earlier if, subsequent to such Business Combination, and (2) the date
on which the closing sale price of the Ordinary Shares equals or exceeds $12.50 per share (as adjusted for stock splits, stock
dividends, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day period commencing
after such Business Combination and, with respect to the remaining 50% of the Private Shares, upon one year after the consummation
of a Business Combination or earlier if, subsequent to such Business Combination, the Company consummates a subsequent liquidation,
merger, stock exchange or other similar transaction that results in all of the Company’s shareholders having the right to
exchange their Ordinary Shares for cash, securities or other property. For purposes of this Agreement, “Transfer”
shall mean the (x) sale of, offer to sell, contract or agreement to sell, hypothecate, pledge, grant of any option to purchase
or otherwise dispose of or agreement to dispose of, directly or indirectly, or establishment or increase of a put equivalent position
or liquidation with respect to or decrease of a call equivalent position within the meaning of Section 16 of the Securities Exchange
Act of 1934, as amended, and the rules and regulations of the Securities and Exchange Commission (the “Commission”)
promulgated thereunder with respect to, any security, (y) entry into any swap or other arrangement that transfers to another, in
whole or in part, any of the economic consequences of ownership of any security, whether any such transaction is to be settled
by delivery of such securities, in cash or otherwise, or (z) public announcement of any intention to effect any transaction specified
in clause (x) or (y).


 


(iii)  Notwithstanding the provisions set
forth in paragraph 5.2(i), Transfers of the Private Shares and any Securities are permitted to (a) to any members of the Purchaser
or any affiliates of the Purchaser or any of its members; (b) by private sales or transfers made in connection with the consummation
of a Business Combination at prices no greater than the price at which the securities were originally purchased; (c) in the event
of the Company’s liquidation prior to the completion of a Business Combination; or (d) by virtue of the laws of the State
of Delaware or the Purchaser’s limited liability company agreement upon dissolution of the Purchaser; provided, however,
that in the case of clauses (a) through (c), these permitted transferees must enter into a written agreement agreeing to be bound
by the transfer restrictions described herein.


 


6.   Securities Laws Restrictions


 


The Purchaser agrees not to sell, transfer,
pledge, hypothecate or otherwise dispose of all or any part of the Securities unless, prior thereto (a) a registration statement
on the appropriate form under the Securities Act and applicable state securities laws with respect to the Securities proposed to
be transferred shall then be effective or (b) the Company shall have received an opinion from counsel reasonably satisfactory
to the Company, that such registration is not required because such transaction complies with the Securities Act and the rules
promulgated by the Commission thereunder and with all applicable state securities laws.


 


7.   Partial Forfeiture in Connection
with Business Combination Closing


 


If, in connection with the closing of the
Business Combination, the Sponsor agrees to forfeit any Founder Shares and/or Founder Units to the Company at no cost or subject
its Founder Shares and/or Founder Units to contractual terms or restrictions, convert its Founder Shares and/or Founder Units (including
the Ordinary Shares and Warrants comprising such Founder Units) into other securities or contractual rights or otherwise modify
the terms of its Founder Shares and/or Founder Units, then, provided that the Sponsor is not being issued any other equity or equity-related
securities in the Business Combination not also being issued to the Purchaser on a pro rata basis, the Purchaser agrees to forfeit,
subject, convert or modify its Private Shares and/or Private Units, as applicable, on a pro rata basis and on the same terms as
the Sponsor and any other holders of Founder Shares and/or Founder Units. Any forfeiture under this Agreement shall take effect
as a surrender for no consideration as a matter of British Virgin Islands law.


 




    		9	 



     


    

 


8.  Waiver of Distributions from Trust
Account


 


In connection with the Securities and the
Private Shares acquired pursuant to this Agreement, the Purchaser hereby waives any and all right, title, interest or claim of
any kind in or to any distributions from the Trust Account.


 


9.   Rescission Right Waiver


 


9.1.  Rescission Waiver. The Purchaser
understands and acknowledges that an exemption from the registration requirements of the Securities Act requires there be no general
solicitation of purchasers of the Private Units or the Private Shares. In this regard, if the Offering were deemed to be a general
solicitation with respect to the Private Units, the offer and sale of such Private Units may not be exempt from registration and,
if not, the Purchaser may have a right to rescind its purchase of the Private Units. In order to facilitate the completion of the
Offering and in order to protect the Company, its shareholders and the Trust Account from claims that may adversely affect the
Company or the interests of its shareholders, the Purchaser hereby agrees to waive, to the maximum extent permitted by applicable
law, any claims, right to sue or rights in law or arbitration, as the case may be, to seek rescission of its purchase of the Private
Units as a result of the issuance of the Private Units being deemed to be in violation of Section 5 of the Securities Act. The
Purchaser acknowledges and agrees this waiver is being made in order to induce the Company to sell the Private Units to the Purchaser.
The Purchaser agrees the foregoing waiver of rescission rights shall apply to any and all known or unknown actions, causes of action,
suits, claims or proceedings (collectively, “Claims”) and related losses, costs, penalties, fees, liabilities
and damages, whether compensatory, consequential or exemplary, and expenses in connection therewith, including reasonable attorneys’
and expert witness fees and disbursements and all other expenses reasonably incurred in investigating, preparing or defending against
any Claims, whether pending or threatened, in connection with any present or future actual or asserted right to rescind the purchase
of the Units hereunder or relating to the purchase of the Private Units and the transactions contemplated hereby.


 


9.2.  No Recourse Against Trust Account.
The Purchaser agrees not to seek recourse against the Trust Account for any reason whatsoever in connection with its acquisition
of the Private Units or the Private Shares or any Claim that may arise now or in the future.


 


9.3.  Section 8 Waiver. The Purchaser
agrees that to the extent any waiver of rights under this Section 9 is ineffective as a matter of law, the Purchaser has offered
such waiver for the benefit of the Company as an equitable right that shall survive any statutory disqualification or bar that
applies to a legal right. The Purchaser acknowledges the receipt and sufficiency of consideration received from the Company hereunder
in this regard.


 


10.  Terms of the Private Units and Private
Shares; Voting


 




    		10	 



     


    

 


10.1 Terms of the Private Units and
Private Shares. The Private Units shall be substantially identical to the Public Units, except the Private Units: (i) will
be subject to the transfer restrictions described herein; (ii) are being purchased pursuant to an exemption from the registration
requirements of the Securities Act and will become freely tradable only after certain conditions are met or the resale of the Private
Units is registered under the Securities Act; and (iii) the Warrants underlying the Private Units are not redeemable by the Company,
provided the Private Units are held by the Purchaser or its permitted transferees. The Private Shares shall be identical to the
Founder Shares, and the Private Shares shall be identical to the Ordinary Shares comprising the Public Units, except that the Private
Shares: (i) will be subject to the transfer restrictions described herein; (ii) are being purchased pursuant to an exemption from
the registration requirements of the Securities Act and will become freely tradable only after certain conditions are met or the
resale of the Private Units is registered under the Securities Act.


 


10.2 Voting. The Purchaser agrees
that if the Company seeks shareholder approval of a proposed Business Combination, then in connection with such proposed Business
Combination, the Purchaser shall vote the Private Shares and any other Ordinary Shares owned by it in favor of such proposed Business
Combination. The Purchaser agrees: (i) not to propose an amendment to the Company’s Memorandum and Articles of Association
with respect to its pre-Business Combination activities prior to the consummation of such a Business Combination unless the Company
provides dissenting public shareholders with the opportunity to redeem their Ordinary Shares in conjunction with any such amendment;
and (ii) not to redeem any Ordinary Shares owned by it (including the Private Shares) into the right to receive cash from the Trust
Account in connection with a shareholder vote to approve the Company’s proposed initial Business Combination (or to sell
any Ordinary Shares in a tender offer in connection with a proposed Business Combination if the Company does not seek shareholder
approval in connection therewith) or a vote to amend the provisions of the Company’s Memorandum and Articles of Association
relating to shareholders’ rights or pre-Business Combination activity.


 


11. Governing Law; Jurisdiction;
Waiver of Jury Trial


 


11.1 Governing Law. This Agreement,
the entire relationship of the parties hereto, and any litigation between the parties (whether grounded in contract, tort, statute,
law or equity) shall be governed by, construed in accordance with, and interpreted pursuant to the laws of the State of New York,
including, without limitation, Sections 5-1401 and 5-1402 of the New York General Obligations Law and New York Civil Practice Laws
and Rules 327(b).


 


11.2 Jurisdiction. The parties (i)
hereby irrevocably and unconditionally submit to the jurisdiction of the state courts of New York and to the jurisdiction of the
United States District Court for the Southern District of New York for the purpose of any suit, action or other proceeding arising
out of or based upon this Agreement, (b) agree not to commence any suit, action or other proceeding arising out of or based upon
this Agreement except in state courts of New York or the United States District Court for the Southern District of New York, and
(c) hereby waive, and agree not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding,
any claim that it is not subject personally to the jurisdiction of the above-named courts, that its property is exempt or immune
from attachment or execution, that the suit, action or proceeding is brought in an inconvenient forum, that the venue of the suit,
action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such court.


 


11.3 Waiver of Jury Trial. The parties
hereto hereby waive any right to a jury trial in connection with any litigation pursuant to this agreement and the transactions
contemplated hereby.


 


12. Assignment; Entire Agreement; Amendment


 


12.1. Assignment. Neither this Agreement
nor any rights hereunder may be assigned by any party to any other person other than by the Purchaser, without the prior consent
of the Company, to one or more persons agreeing to be bound by the terms hereof. Upon such assignment by a Purchaser, the assignee(s)
shall become Purchaser hereunder and have the rights and obligations provided for herein to the extent of such assignment.


 




    		11	 



     


    

 


12.2. Entire Agreement. This Agreement,
together with any documents, instruments and writings that are delivered pursuant hereto or referenced herein, constitutes the
entire agreement and understanding between the parties as to the subject matter hereof and supersedes any and all prior discussions,
agreements and understandings of any and every nature.


 


12.3. Amendment. Except as expressly
provided in this Agreement, neither this Agreement nor any term hereof may be amended, waived, discharged or terminated other than
by a written instrument signed by the party against whom enforcement of any such amendment, waiver, discharge or termination is
sought.


 


12.4. Binding upon Successors. This
Agreement shall be binding upon and inure to the benefit of the parties hereto and to their respective heirs, legal representatives,
successors and permitted assigns.


 


13. Notices


 


All notices, requests, consents and other
communications hereunder shall be in writing, shall be addressed to the receiving party’s address set forth herein or to
such other address as a party may designate by notice hereunder, and shall be either (a) delivered by hand, (b) sent by overnight
courier, or (c) sent by certified mail, return receipt requested, postage prepaid. All notices, requests, consents and other communications
hereunder shall be deemed to have been given either (i) if by hand, at the time of the delivery thereof to the receiving party
at the address of such party set forth above, (ii) if sent by overnight courier, on the next business day following the day such
notice is delivered to the courier service, or (iii) if sent by certified mail, on the fifth business day following the day such
mailing is made.


 


14. Tax Information


 


14.1 Form W-9. The Purchaser has,
concurrently with the execution of this Agreement, executed and delivered the Internal Revenue Service Form W-9 attached hereto
as Exhibit A.


 


14.2 QEF Election Information. As
soon as practicable following the close of each taxable year of the Company, the Company shall determine whether the Company is
or was deemed to be a “passive foreign investment company” (a “PFIC”) within the meaning
of U.S. Internal Revenue Code of 1986, as amended, and the regulations promulgated thereunder (collectively, the “Code”)
for such taxable year. If the Company determines that the Company is or was a PFIC in any year, for the year of determination and
for each year thereafter during which the Purchaser holds an equity interest in the Company, including Warrants, the Company shall
(i) make available to the Purchaser the information that may be required to make or maintain a “qualified electing fund”
election under the Code with respect to the Company and (ii) furnish the information required to be reported under Section 1298(f)
of the Code.


 


15. Counterparts


 


This Agreement may be executed in one or
more counterparts, all of which when taken together 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, it being understood that both parties need not sign
the same counterpart.  In the event that any signature is delivered by facsimile transmission or any other form of electronic
delivery, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature
is executed) with the same force and effect as if such signature page were an original thereof.


 




    		12	 



     


    

 


16. Survival; Severability


 


16.1. Survival. The representations
and warranties of the parties hereto shall survive the Closing until one (1) year following the consummation of an initial Business
Combination.


 


16.2. Severability. In the event
that any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or
void, this Agreement shall continue in full force and effect without said provision; provided that no such severability
shall be effective if it materially changes the economic benefit of this Agreement to any party.


 


17. Headings


 


The titles and subtitles used in this Agreement
are used for convenience only and are not to be considered in construing or interpreting this Agreement.


 


18. Construction


 


The parties hereto have participated jointly
in the negotiation and drafting of this Agreement. If an ambiguity or question of intent or interpretation arises, this Agreement
will be construed as if drafted jointly by the parties hereto and no presumption or burden of proof will arise favoring or disfavoring
any party hereto because of the authorship of any provision of this Agreement. The words “include,” “includes,”
and “including” will be deemed to be followed by “without limitation.” Pronouns in masculine,
feminine, and neuter genders will be construed to include any other gender, and words in the singular form will be construed to
include the plural and vice versa, unless the context otherwise requires. The words “this Agreement,” “herein,”
“hereof,” “hereby,” “hereunder,” and words of similar import refer to
this Agreement as a whole and not to any particular subdivision unless expressly so limited. The parties hereto intend that each
representation, warranty, and covenant contained herein will have independent significance. If any party hereto has breached any
representation, warranty, or covenant contained herein in any respect, the fact that there exists another representation, warranty
or covenant relating to the same subject matter (regardless of the relative levels of specificity) which such party hereto has
not breached will not detract from or mitigate the fact that such party hereto is in breach of the first representation, warranty,
or covenant. 


 


[REMAINDER OF PAGE INTENTIONALLY LEFT
BLANK]


 




    		13	 



     


    

 


This subscription is accepted by the Company as of the date
first written above.


 


	 	CONSTELLATION ALPHA CAPITAL CORP.
	 	 	 
	 	By:	/s/ Rajiv Shukla
	 	Name: 	 Rajiv Shukla
	 	Title: 	Chief Executive Officer


  


Accepted and agreed this


17th day of May, 2017


 


COWEN INVESTMENTS LLC


 


	By:	/s/ Stephen LaSota	 
	Name:	Stephen LaSota	 
	Title: 	
        Chief Financial Officer 
	 


 


[Signature Page to Unit Subscription
Agreement]


 




     

     


    

 


Exhibit
A


 


FORM W-9


 


[Attached]