Exhibit 10.6


 


October __, 2020


 


Petra Acquisition,
Inc.


5 West 21st
Street


New York,
NY 10010


 


LifeSci
Capital LLC


250 West 55th Street, 34th Floor


New York, New York 10019


 


Ladenburg Thalmann & Co. Inc.


277 Park Avenue, 26th Floor


New York, NY 10172


 


	 	Re:	Initial Public Offering


 


Gentlemen:


 


This letter is being
delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Petra Acquisition, Inc., a Delaware corporation (the “Company”), and LifeSci Capital
LLC and Ladenburg Thalmann & Co. Inc. as representatives (together the “Representatives” and each
a “Representative”) of the several Underwriters named in Schedule I thereto (the “Underwriters”),
relating to an underwritten initial public offering (the “IPO”) of the Company’s units (the “Units”),
each comprised of one share of the Company’s common stock, par value $0.001 per share (the “Common Stock”),
and one warrant, each warrant exercisable for one share of Common Stock (each, a “Warrant”). Certain
capitalized terms used herein are defined in paragraph 14 hereof.


 


In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:


 


1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her, or it, whether acquired before, in, or after the IPO, in favor of such Business Combination.


 


2. (a) In the event that
the Company fails to consummate a Business Combination within the time period set forth in the Company’s Amended and Restated
Certificate of Incorporation, as the same may be amended from time to time (the “Certificate of Incorporation”),
the undersigned will, as promptly as possible, cause the Company to (i) cease all operations except for the purpose of winding
up, (ii) as promptly as reasonably possible, but not more than 10 business days thereafter, redeem the IPO Shares at a per-share
price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the Trust
Account net of interest released to the Company as permitted pursuant to the Trust Agreement, divided by the number of then outstanding
IPO Shares, which redemption will completely extinguish public stockholders’ rights as stockholders (including the right
to receive further liquidation distributions, if any), and (iii) as promptly as reasonably possible following such redemption,
subject to the approval of the Company’s remaining stockholders and the Company’s board of directors, dissolve and
liquidate, subject in the cases of clauses (ii) and (iii) to the Company’s obligations under Delaware law to provide for
claims of creditors and other requirements of applicable law.


 


(b) The undersigned hereby
waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Account (“Claim”)
with respect to the shares of Founders’ Common Stock owned by the undersigned and hereby waives any Claim the undersigned
may have in the future as a result of, or arising out of, any contracts or agreements with the Company and will not seek recourse
against the Trust Account for any reason whatsoever. The undersigned acknowledges and agrees that there will be no distribution
from the Trust Account with respect to any Warrants, all rights of which will terminate on the Company’s liquidation.


 






     


     


    

 


[(c) In the event of
the liquidation of the Trust Account, the undersigned agrees to indemnify and hold harmless the Company for any debts and obligations
to target businesses or vendors or other entities that are owed money by the Company for services rendered or contracted for or
products sold to the Company, but only to the extent necessary to ensure that such debt or obligation does not reduce the amount
of funds in the Trust Account below $10.10 per share; provided that such indemnity shall not apply (i) if such vendor or prospective
target business executed an agreement waiving any right, title, interest or claim of any kind they may have in or to any monies
held in the Trust Account, or (ii) as to any claims under the Company’s obligation to indemnify the Underwriters against
certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “Securities Act”).]1


 


3. The undersigned acknowledges
and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders of the
Company or their affiliates, such transaction must be approved by a majority of the Company’s disinterested independent directors
and the Company must obtain an opinion from an independent investment banking firm, or another independent entity that commonly
renders valuation opinions, that such Business Combination is fair to the Company’s unaffiliated stockholders from a financial
point of view.


 


4. Neither the undersigned
nor any affiliate of the undersigned will be entitled to receive and will not accept any compensation or other cash payment prior
to, or for services rendered in order to effectuate, the consummation of the Business Combination; provided that the Company shall
be allowed to make the payments set forth in the Registration Statement under the caption “Prospectus Summary – The
Offering – Limited payments to insiders.”


 


5. Neither the undersigned
nor any affiliate of the undersigned will be entitled to receive or accept a finder’s fee or any other compensation in the
event either of the undersigned or any affiliate of the undersigned originates a Business Combination.


 


6. (a) The undersigned
will place into escrow all shares of Founders’ Common Stock owned by him/her/it pursuant to the terms of a Stock Escrow Agreement
which the Company will enter into with the undersigned and an escrow agent.


 


(b) The undersigned agrees
that until after the Company consummates a Business Combination, all Private Securities owned by him/her/it will be subject to
the transfer restrictions described in the Subscription Agreement relating to the undersigned’s Private Securities.


 


7. (a) In order to minimize
potential conflicts of interest that may arise from multiple corporate affiliations, the undersigned hereby agrees that until the
earliest of the Company’s initial Business Combination or liquidation, the undersigned shall present to the Company for its
consideration, prior to presentation to any other entity, any suitable target business, subject to any pre-existing fiduciary or
contractual obligations the undersigned might have.


 


(b) The undersigned hereby
agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach of
any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.


 


8. The undersigned agrees
to be the [_____] of the Company until the earlier of the consummation by the Company of a Business Combination
or the liquidation of the Company. The undersigned’s biographical information previously furnished to the Company and the
Representatives is true and accurate in all respects, does not omit any material information with respect to the undersigned’s
background and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under
the Securities Act. The undersigned’s FINRA Questionnaire previously furnished to the Company and the Representatives is
true and accurate in all respects. The undersigned represents and warrants that:


 


(a) he/she/it has never
had a petition under the federal bankruptcy laws or any state insolvency law been filed by or against (i) him/her/it or any partnership
in which he/she/it was a general partner at or within two years before the time of filing; or (ii) any corporation or business
association of which he/she/it was an executive officer at or within two years before the time of such filing;


 





 






1 For Sponsor letter
only


 



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(b) he/she/it has never
had a receiver, fiscal agent or similar officer been appointed by a court for his/her/its business or property, or any such partnership;


 


(c) he/she/it has never
been convicted of fraud in a civil or criminal proceeding;


 


(d) he/she/it/ has never
been convicted in a criminal proceeding or named the subject of a pending criminal proceeding (excluding traffic violations and
minor offenses);


 


(e) he/she/it has never
been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated, of any court of competent jurisdiction,
permanently or temporarily enjoining or otherwise limiting him/her/it from (i) acting as a futures commission merchant, introducing
broker, commodity trading advisor, commodity pool operator, floor broker, leverage transaction merchant, any other person regulated
by the Commodity Futures Trading Commission (“CFTC”) or an associated person of any of the foregoing,
or as an investment adviser, underwriter, broker or dealer in securities, or as an affiliated person, director or employee of any
investment company, bank, savings and loan association or insurance company, or from engaging in or continuing any conduct or practice
in connection with any such activity; or (ii) engaging in any type of business practice; or (iii) engaging in any activity
in connection with the purchase or sale of any security or commodity or in connection with any violation of federal or state securities
or federal commodities laws;


 


(f) he/she/it has never
been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated, of any federal or state authority
barring, suspending or otherwise limiting for more than 60 days his/her/its right to engage in any activity described in 9(e)(i)
above, or to be associated with persons engaged in any such activity;


 


(g) he/she/it has never
been found by a court of competent jurisdiction in a civil action or by the SEC to have violated any federal or state securities
law, where the judgment in such civil action or finding by the SEC has not been subsequently reversed, suspended or vacated;


 


(h) he/she/it has never
been found by a court of competent jurisdiction in a civil action or by the CFTC to have violated any federal commodities law,
where the judgment in such civil action or finding by the CFTC has not been subsequently reversed, suspended or vacated;


 


(i) he/she/it has never
been the subject of, or a party to, any Federal or State judicial or administrative order, judgment, decree or finding, not subsequently
reversed, suspended or vacated, relating to an alleged violation of (i) any Federal or State securities or commodities law or regulation,
(ii) any law or regulation respecting financial institutions or insurance companies including, but not limited to, a temporary
or permanent injunction, order of disgorgement or restitution, civil money penalty or temporary or permanent cease-and desist order,
or removal or prohibition order or (iii) any law or regulation prohibiting mail or wire fraud or fraud in connection with any business
entity;


 


(j) he/she/it has never
been the subject of, or party to, any sanction or order, not subsequently reversed, suspended or vacated, or any self-regulatory
organization, any registered entity, or any equivalent exchange, association, entity or organization that has disciplinary authority
over its members or persons associated with a member;


 


(k) he/she/it has never
been convicted of any felony or misdemeanor: (i) in connection with the purchase or sale of any security; (ii) involving the making
of any false filing with the SEC; or (iii) arising out of the conduct of the business of an underwriter, broker, dealer, municipal
securities dealer, investment advisor or paid solicitor of purchasers of securities;


 






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(l) he/she/it was never
subject to a final order of a state securities commission (or an agency of officer of a state performing like functions); a state
authority that supervises or examines banks, savings associations, or credit unions; a state insurance commission (or an agency
or officer of a state performing like functions); an appropriate federal banking agency; the Commodity Futures Trading Commission;
or the National Credit Union Administration that is based on a violation of any law or regulation that prohibits fraudulent, manipulative,
or deceptive conduct; 


 


(m) he/she/it has never
been subject to any order, judgment or decree of any court of competent jurisdiction, that, at the time of such sale, restrained
or enjoined him/her/it from engaging or continuing to engage in any conduct or practice: (i) in connection with the purchase or
sale of any security; (ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct of the business
of an underwriter, broker, dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;


 


(n) he/she/it has never
been subject to any order of the SEC that orders him/her/it to cease and desist from committing or causing a future violation of:
(i) any scienter-based anti-fraud provision of the federal securities laws, including, but not limited to, Section 17(a)(1) of
the Securities Act, Section 10(b) of the Exchange Act and Rule 10b-5 thereunder, and Section 206(1) of the Advisers Act or any
other rule or regulation thereunder; or (ii) Section 5 of the Securities Act;


 


(o) he/she/it has never
been named as an underwriter in any registration statement or Regulation A offering statement filed with the SEC that was the subject
of a refusal order, stop order, or order suspending the Regulation A exemption, or is, currently, the subject of an investigation
or proceeding to determine whether a stop order or suspension order should be issued;


 


(p) he/she/it has never
been subject to a United States Postal Service false representation order, or is currently subject to a temporary restraining order
or preliminary injunction with respect to conduct alleged by the United States Postal Service to constitute a scheme or device
for obtaining money or property through the mail by means of false representations;


 


(q) he/she/it is not subject
to a final order of a state securities commission (or an agency of officer of a state performing like functions); a state authority
that supervises or examines banks, savings associations, or credit unions; a state insurance commission (or an agency or officer
of a state performing like functions); an appropriate federal banking agency; the Commodity Futures Trading Commission; or the
National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated by such commission,
authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging in savings association
or credit union activities;


 


(r) he/she/it is not subject
to an order of the SEC entered pursuant to section 15(b) or 15B(c) of the Securities Exchange Act of 1934, as amended (the “Exchange
Act”), or section 203(e) or 203(f) of the Investment Advisers Act of 1940, as amended (the “Advisers
Act”), that: (i) suspends or revokes the undersigned’s registration as a broker, dealer, municipal securities
dealer or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes civil money penalties
on, such person; or (iii) bars the undersigned from being associated with any entity or from participating in the offering of any
penny stock; and


 


(s) he/she/it has never
been suspended or expelled from membership in, or suspended or barred from association with a member of, a securities self-regulatory
organization (e.g., a registered national securities exchange or a registered national or affiliated securities association) for
any act or omission to act constituting conduct inconsistent with just and equitable principles of trade.


 


9. The undersigned has
full right and power, without violating any agreement by which he, she or it is bound, to enter into this letter agreement [and
to serve as a director and/or officer of the Company].


 


10. The undersigned hereby
waives any right to exercise conversion rights with respect to any shares of the Company’s common stock owned or to be owned
by the undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether such shares be part
of the Founders’ Common Stock or shares purchased by the undersigned in the IPO or in the aftermarket, and agrees not to
seek conversion with respect to such shares in connection with any vote to approve a Business Combination (or sell such shares
to the Company in a tender offer in connection with such a Business Combination).


 






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11. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to Article Sixth of the Certificate of Incorporation prior to the consummation
of a Business Combination unless the Company provides public stockholders with the opportunity to convert their shares of Common
Stock upon such approval in accordance with such Article Sixth thereof.


 


[12. In the event that
the Company does not consummate a Business Combination and must liquidate and its remaining net assets are insufficient to complete
such liquidation, the undersigned agrees to advance such funds necessary to complete such liquidation and agrees not to seek repayment
for such expenses.]2


 


13. This letter agreement
shall be governed by and construed and enforced in accordance with the laws of the State of New York, without giving effect to
conflicts of law principles that would result in the application of the substantive laws of another jurisdiction. Each of the Company
and the undersigned hereby (i) agrees that any action, proceeding or claim against him arising out of or relating in any way to
this letter agreement (a “Proceeding”) shall be brought and enforced in the courts of the State of New
York of the United States of America for the Southern District of New York, and irrevocably submits to such jurisdiction, which
jurisdiction shall be exclusive and (ii) waives any objection to such exclusive jurisdiction and that such courts represent an
inconvenient forum. The undersigned irrevocably agrees to appoint Horwitz + Armstrong as agent for the service of process in the
State of New York to receive, for the undersigned and on his behalf, service of process in any Proceeding. If for any reason such
agent is unable to act as such, the undersigned will promptly notify the Company and the Representatives and appoint a substitute
agent acceptable to each of the Company and the Representatives within 30 days and nothing in this letter will affect the right
of either party to serve process in any other manner permitted by law.


 


14. As used herein, (i)
a “Business Combination” means a merger, share exchange, asset acquisition, stock purchase, recapitalization,
reorganization or other similar business combination with one or more businesses or entities; (ii) “Insiders”
means all officers, directors and sponsor of the Company immediately prior to the IPO; (iii) “Founders’ Common
Stock” means all of the shares of Common Stock of the Company acquired by an Insider prior to the IPO; (iv) “IPO
Shares” means the shares of Common Stock issued in the Company’s IPO; (v) “Private Securities”
means the warrants that are being sold privately by the Company simultaneously with the consummation of the IPO; (vi) “Trust
Agreement” means the Investment Management Trust Agreement between the Company and Continental Stock Transfer &
Trust Company being entered into in connection with the IPO and governing the use of funds held in the Trust Account; (vii) “Trust
Account” means the trust account into which a portion of the net proceeds of the IPO will be deposited; and (viii)
“Registration Statement” means the Company’s registration statement on Form S-1 (SEC File No. 333-240175)
filed with the Securities and Exchange Commission.


 


15. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.


 


16. Each of the undersigned
acknowledges and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties
set forth herein in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative
of, or a fiduciary with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the
subject matter hereof.


  


[Signature Page Follows]


 





 






2 For Sponsor letter only.


 






    5


     


    

 


	 	[_____]
	 	Print Name of Insider
	 	 
	 	 
	 	Signature
	 	 
	 	Acknowledged and Agreed:
	 	 
	 	PETRA ACQUISITION, INC.
	 	 
	 	By:	 
	 	 	Name: Andreas Typaldos
	 	 	Title: Chief Executive Officer


 


 


[signature page of insider letter]


 


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