Exhibit 4.2


 


FORM OF COMMON STOCK PURCHASE WARRANT


 


BIOSTAGE,
INC.


 


	Warrant Shares: _______	Issue Date: February __, 2017
	 	 
	 	Initial Exercise Date:


 


THIS COMMON STOCK PURCHASE
WARRANT (the “Warrant”) certifies that, for value received, _____________ or its assigns (the “Holder”)
is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on
or after _________________ (the “Initial Exercise Date”) and on or prior to the close of business on the five
year anniversary of the effective date of the registration statement pursuant to which this Warrant is issued (the “Termination
Date”) but not thereafter, to subscribe for and purchase from Biostage, Inc., a Delaware corporation (the “Company”),
up to ______ shares (as subject to adjustment hereunder, the “Warrant Shares”) of Common Stock. The purchase
price of one share of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b). This Warrant
is issued pursuant to the Engagement Agreement, dated January 3, 2017, between the Company and Rodman & Renshaw, a unit of
H.C. Wainwright & Co., LLC.


 


Section 1.        Definitions.
Capitalized terms used and not otherwise defined herein shall have the meanings set forth in that certain Securities Purchase
Agreement (the “Purchase Agreement”), dated February ___, 2017, among the Company and the purchasers signatory
thereto.


 


Section 2.         Exercise.


 


a)       Exercise
of Warrant. Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times
on or after the Initial Exercise Date and on or before the Termination Date by delivery to the Company (or such other office or
agency of the Company as it may designate by notice in writing to the registered Holder at the address of the Holder appearing
on the books of the Company) of a duly executed facsimile copy (or e-mail attachment) of the Notice of Exercise in the form annexed
hereto. Within the earlier of (i) three (3) Trading Days and (ii) the number of Trading Days comprising the Standard Settlement
Period (as defined in Section 2(d)(i) herein) following the date of exercise as aforesaid, the Holder shall deliver the aggregate
Exercise Price for the shares specified in the applicable Notice of Exercise by wire transfer or cashier’s check drawn on
a United States bank unless the cashless exercise procedure specified in Section 2(c) below is specified in the applicable Notice
of Exercise. No ink-original Notice of Exercise shall be required, nor shall any medallion guarantee (or other type of guarantee
or notarization) of any Notice of Exercise form be required. Notwithstanding anything herein to the contrary, the Holder shall
not be required to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant Shares available
hereunder and the Warrant has been exercised in full, in which case, the Holder shall surrender this Warrant to the Company for
cancellation within three (3) Trading Days of the date the final Notice of Exercise is delivered to the Company. Partial exercises
of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available hereunder shall have the effect
of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to the applicable number of Warrant
Shares purchased. The Holder and the Company shall maintain records showing the number of Warrant Shares purchased and the date
of such purchases. The Company shall deliver any objection to any Notice of Exercise within one (1) Business Day of receipt of
such notice. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions
of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available
for purchase hereunder at any given time may be less than the amount stated on the face hereof.


 




    	 	1	 



     


    

 


b)       Exercise
Price. The exercise price per share of the Common Stock under this Warrant shall be $______, subject to adjustment
hereunder (the “Exercise Price”).


 


c)       Cashless
Exercise. If at any time after the Initial Exercise Date, there is no effective Registration Statement registering, or no
current prospectus available for, the issuance of the Warrant Shares by the Holder, then this Warrant may only be exercised, in
whole or in part, at such time by means of a “cashless exercise” in which the Holder shall be entitled to receive
a number of Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:


 


(A) = the last
VWAP immediately preceding the time of delivery of the Notice of Exercise giving rise to the applicable “cashless exercise”,
as set forth in the applicable Notice of Exercise (to clarify, the “last VWAP” will be the last VWAP as calculated
over an entire Trading Day such that, in the event that this Warrant is exercised at a time that the Trading Market is open, the
prior Trading Day’s VWAP shall be used in this calculation);


 


(B) = the Exercise
Price of this Warrant, as adjusted hereunder; and


 


(X) = the
number of Warrant Shares that would be issuable upon exercise of this Warrant in accordance with the terms of this Warrant if
such exercise were by means of a cash exercise rather than a cashless exercise.


 


If
Warrant Shares are issued in such a cashless exercise, the parties acknowledge and agree that in accordance with Section 3(a)(9)
of the Securities Act, the Warrant Shares shall take on the characteristics of the Warrants being exercised, and the holding period
of the Warrants being exercised may be tacked on to the holding period of the Warrant Shares.  The Company agrees not
to take any position contrary to this Section 2(c).


 


“VWAP”
means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then
listed or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest
preceding date) on the Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (based
on a Trading Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)), (b)  if the Common Stock is not
then listed on a Trading Market and if prices for the Common Stock are then listed or quoted for trading on OTCQB or OTCQX, the
volume weighted average price of the Common Stock for such date (or the nearest preceding date) on OTCQB or OTCQX as applicable,
(c) if the Common Stock is not then listed or quoted for trading on OTCQB or OTCQX and if prices for the Common Stock are then
reported in the “Pink Sheets” published by OTC Markets, Inc. (or a similar organization or agency succeeding to its
functions of reporting prices), the most recent bid price per share of the Common Stock so reported, or (d) in all other
cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the
Holders of a majority in interest of the Warrants then outstanding and reasonably acceptable to the Company, the fees and expenses
of which shall be paid by the Company.


 




    	 	2	 



     


    

 


 d)       Mechanics of Exercise.




 


 i.    Delivery of Warrant Shares Upon Exercise. The Company shall cause the Warrant Shares purchased hereunder to be transmitted by the Transfer Agent to the Holder by either (I) crediting the account of the Holder’s or its designee’s balance account with The Depository Trust Company through its Deposit or Withdrawal at Custodian system (“DWAC”) if the Company is then a participant in such system and either (A) there is an effective registration statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by Holder (although for avoidance of any doubt, the Company is not obligated in any manner or circumstance to file or maintain any such resale registration statement), or (B) the Warrant Shares are eligible for resale by the Holder without volume or manner of sale limitations pursuant to Rule 144, or (C) if applicable and permitted under 2(c), this Warrant is being exercised via cashless exercise, or (II) and otherwise by physical delivery of a certificate, registered in the Company’s share register in the name of the Holder or its designee, for the number of Warrant Shares to which the Holder is entitled pursuant to such exercise to the address specified by the Holder in the Notice of Exercise by the date that is the earlier of (i) three (3) Trading Day and (ii) the number of Trading Days comprising the Standard Settlement Period after the delivery to the Company of the Notice of Exercise (such date, the “Warrant Share Delivery Date”). Upon delivery of the Notice of Exercise, the Holder shall be deemed for all corporate purposes to have become the holder of record of the Warrant Shares with respect to which this Warrant has been exercised, irrespective of the date of delivery of the Warrant Shares, provided that payment of the aggregate Exercise Price (other than in the case of a cashless exercise) is received within the earlier of (i) three Trading Days and (ii) the number of Trading Days comprising the Standard Settlement Period following delivery of the Notice of Exercise. If the Company fails for any reason to deliver to the Holder the Warrant Shares subject to a Notice of Exercise by the Warrant Share Delivery Date, the Company shall pay to the Holder, in cash, as liquidated damages and not as a penalty, for each $1,000 of Warrant Shares subject to such exercise (based on the VWAP of the Common Stock on the date of the applicable Notice of Exercise), $10 per Trading Day (increasing to $20 per Trading Day on the fifth Trading Day after such liquidated damages begin to accrue) for each Trading Day after such Warrant Share Delivery Date until such Warrant Shares are delivered or Holder rescinds such exercise. The Company agrees to maintain a transfer agent that is a participant in the FAST program so long as this Warrant remains outstanding and exercisable. As used herein, “Standard Settlement Period” means the standard settlement period, expressed in a number of Trading Days, on the Company’s primary Trading Market with respect to the Common Stock as in effect on the date of delivery of the Notice of Exercise.




 




    	 	3	 



     


    

 


ii.      Delivery
of New Warrants Upon Exercise. If this Warrant shall have been exercised in part, the Company shall, at the request of a Holder
and upon surrender of this Warrant certificate, at the time of delivery of the Warrant Shares, deliver to the Holder a new Warrant
evidencing the rights of the Holder to purchase the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall
in all other respects be identical with this Warrant.


 


iii.     Rescission
Rights. If the Company fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares pursuant to Section
2(d)(i) by the Warrant Share Delivery Date, then the Holder will have the right to rescind such exercise.


 


iv.     Compensation
for Buy-In on Failure to Timely Deliver Warrant Shares Upon Exercise. In addition to any other rights available to the Holder,
if the Company fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares in accordance with the provisions
of Section 2(d)(i) above pursuant to an exercise on or before the Warrant Share Delivery Date, and if after such date the Holder
is required by its broker to purchase (in an open market transaction or otherwise) or the Holder’s brokerage firm otherwise
purchases, shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated
receiving upon such exercise (a “Buy-In”), then the Company shall (A) pay in cash to the Holder the amount,
if any, by which (x) the Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common
Stock so purchased exceeds (y) the amount obtained by multiplying (1) the number of Warrant Shares that the Company was required
to deliver to the Holder in connection with the exercise at issue times (2) the price at which the sell order giving rise to such
purchase obligation was executed, and (B) at the option of the Holder, either reinstate the portion of the Warrant and equivalent
number of Warrant Shares for which such exercise was not honored (in which case such exercise shall be deemed rescinded) or deliver
to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise
and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000
to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price giving rise to
such purchase obligation of $10,000, under clause (A) of the immediately preceding sentence the Company shall be required to pay
the Holder $1,000. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect
of the Buy-In and, upon request of the Company, evidence of the amount of such loss. Nothing herein shall limit a Holder’s
right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific
performance and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon
exercise of the Warrant as required pursuant to the terms hereof.


 




    	 	4	 



     


    

 


v.     No
Fractional Shares or Scrip. No fractional shares or scrip representing fractional shares shall be issued upon the exercise
of this Warrant. As to any fraction of a share which the Holder would otherwise be entitled to purchase upon such exercise, the
Company shall, at its election, either pay a cash adjustment in respect of such final fraction in an amount equal to such fraction
multiplied by the Exercise Price or round up to the next whole share.


 


vi.     Charges,
Taxes and Expenses. Issuance of Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or
other incidental expense in respect of the issuance of such Warrant Shares, all of which taxes and expenses shall be paid by the
Company, and such Warrant Shares shall be issued in the name of the Holder or in such name or names as may be directed by the
Holder; provided, however, that in the event that Warrant Shares are to be issued in a name other than the name
of the Holder, this Warrant when surrendered for exercise shall be accompanied by the Assignment Form attached hereto duly executed
by the Holder and the Company may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer
tax incidental thereto. The Company shall pay all Transfer Agent fees required for same-day processing of any Notice of Exercise
and all fees to the Depository Trust Company (or another established clearing corporation performing similar functions) required
for same-day electronic delivery of the Warrant Shares.


 




    	 	5	 



     


    

 


vii.   Closing
of Books. The Company will not close its stockholder books or records in any manner which prevents the timely exercise of
this Warrant, pursuant to the terms hereof.


 


e)       Holder’s
Exercise Limitations. The Company shall not effect any exercise of this Warrant, and a Holder shall not have the right to
exercise any portion of this Warrant, pursuant to Section 2 or otherwise, to the extent that after giving effect to such issuance
after exercise as set forth on the applicable Notice of Exercise, the Holder (together with the Holder’s Affiliates, and
any other Persons acting as a group together with the Holder or any of the Holder’s Affiliates (such Persons, “Attribution
Parties”)), would beneficially own in excess of the Beneficial Ownership Limitation (as defined below).  For purposes
of the foregoing sentence, the number of shares of Common Stock beneficially owned by the Holder and its Affiliates and Attribution
Parties shall include the number of shares of Common Stock issuable upon exercise of this Warrant with respect to which such determination
is being made, but shall exclude the number of shares of Common Stock which would be issuable upon (i) exercise of the remaining,
nonexercised portion of this Warrant beneficially owned by the Holder or any of its Affiliates or Attribution Parties and (ii)
exercise or conversion of the unexercised or nonconverted portion of any other securities of the Company (including, without limitation,
any other Common Stock Equivalents) subject to a limitation on conversion or exercise analogous to the limitation contained herein
beneficially owned by the Holder or any of its Affiliates or Attribution Parties.  Except as set forth in the preceding sentence,
for purposes of this Section 2(e), beneficial ownership shall be calculated in accordance with Section 13(d) of the Exchange Act
and the rules and regulations promulgated thereunder, it being acknowledged by the Holder that the Company is not representing
to the Holder that such calculation is in compliance with Section 13(d) of the Exchange Act and the Holder is solely responsible
for any schedules required to be filed in accordance therewith. To the extent that the limitation contained in this Section 2(e)
applies, the determination of whether this Warrant is exercisable (in relation to other securities owned by the Holder together
with any Affiliates and Attribution Parties) and of which portion of this Warrant is exercisable shall be in the sole discretion
of the Holder, and the submission of a Notice of Exercise shall be deemed to be the Holder’s determination of whether this
Warrant is exercisable (in relation to other securities owned by the Holder together with any Affiliates and Attribution Parties)
and of which portion of this Warrant is exercisable, in each case subject to the Beneficial Ownership Limitation, and the Company
shall have no obligation to verify or confirm the accuracy of such determination. In addition, a determination as to any group
status as contemplated above shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations
promulgated thereunder. For purposes of this Section 2(e), in determining the number of outstanding shares of Common Stock, a
Holder may rely on the number of outstanding shares of Common Stock as reflected in (A) the Company’s most recent periodic
or annual report filed with the Commission, as the case may be, (B) a more recent public announcement by the Company or (C) a
more recent written notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding. 
Upon the written or oral request of a Holder, the Company shall within two Trading Days confirm orally and in writing to the Holder
the number of shares of Common Stock then outstanding.  In any case, the number of outstanding shares of Common Stock shall
be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder
or its Affiliates or Attribution Parties since the date as of which such number of outstanding shares of Common Stock was reported.
The “Beneficial Ownership Limitation” shall be 4.99% of the number of shares of the Common Stock outstanding
immediately after giving effect to the issuance of shares of Common Stock issuable upon exercise of this Warrant. The Holder,
upon notice to the Company, may increase or decrease the Beneficial Ownership Limitation provisions of this Section 2(e), provided
that the Beneficial Ownership Limitation in no event exceeds 9.99% of the number of shares of the Common Stock outstanding immediately
after giving effect to the issuance of shares of Common Stock upon exercise of this Warrant held by the Holder and the provisions
of this Section 2(e) shall continue to apply. Any increase in the Beneficial Ownership Limitation will not be effective until
the 61st day after such notice is delivered to the Company. The provisions of this paragraph shall be construed and
implemented in a manner otherwise than in strict conformity with the terms of this Section 2(e) to correct this paragraph (or
any portion hereof) which may be defective or inconsistent with the intended Beneficial Ownership Limitation herein contained
or to make changes or supplements necessary or desirable to properly give effect to such limitation. The limitations contained
in this paragraph shall apply to a successor holder of this Warrant.


 




    	 	6	 



     


    

 


Section 3.         Certain
Adjustments.


 


a)       Stock
Dividends and Splits. If the Company, at any time while this Warrant is outstanding: (i) pays a stock dividend or otherwise
makes a distribution or distributions on shares of its Common Stock or any other equity or equity equivalent securities payable
in shares of Common Stock (which, for avoidance of doubt, shall not include any shares of Common Stock issued by the Company upon
exercise of this Warrant), (ii) subdivides outstanding shares of Common Stock into a larger number of shares, (iii) combines (including
by way of reverse stock split) outstanding shares of Common Stock into a smaller number of shares or (iv) issues by reclassification
of shares of the Common Stock any shares of capital stock of the Company, then in each case the Exercise Price shall be multiplied
by a fraction of which the numerator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding
immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately
after such event, and the number of shares issuable upon exercise of this Warrant shall be proportionately adjusted such that
the aggregate Exercise Price of this Warrant shall remain unchanged, subject to the limitation on fractional shares in Section
2(d)(v). Any adjustment made pursuant to this Section 3(a) shall become effective immediately after the record date for the determination
of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date
in the case of a subdivision, combination or re-classification.


 




    	 	7	 



     


    

 


b)       [Reserved]


 


c)       Subsequent
Rights Offerings. In addition to any adjustments pursuant to Section 3(a) above, if at any time the Company grants, issues
or sells any Common Stock Equivalents or rights to purchase stock, warrants, securities or other property pro rata to the record
holders of any class of shares of Common Stock (the “Purchase Rights”), then the Holder will be entitled to
acquire, upon the terms applicable to such Purchase Rights, the aggregate Purchase Rights which the Holder could have acquired
if the Holder had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard
to any limitations on exercise hereof, including without limitation, the Beneficial Ownership Limitation) immediately before the
date on which a record is taken for the grant, issuance or sale of such Purchase Rights, or, if no such record is taken, the date
as of which the record holders of shares of Common Stock are to be determined for the grant, issue or sale of such Purchase Rights
(provided, however, to the extent that the Holder’s right to participate in any such Purchase Right would result in the
Holder exceeding the Beneficial Ownership Limitation, then the Holder shall not be entitled to participate in such Purchase Right
to such extent (or beneficial ownership of such shares of Common Stock as a result of such Purchase Right to such extent) and
such Purchase Right to such extent shall be held in abeyance for the Holder until such time, if ever, as its right thereto would
not result in the Holder exceeding the Beneficial Ownership Limitation).


 


d)       Pro
Rata Distributions. During such time as this Warrant is outstanding, if the Company shall declare or make any dividend (other
than cash) or other distribution of its assets (or rights to acquire its assets) to holders of shares of Common Stock, by way
of return of capital or otherwise (including, without limitation, any distribution of stock or other securities, property or options
by way of a dividend, spin off, reclassification, corporate rearrangement, scheme of arrangement or other similar transaction)
(a "Distribution"), at any time after the issuance of this Warrant, then, in each such case, the Holder shall
be entitled to participate in such Distribution to the same extent that the Holder would have participated therein if the Holder
had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations
on exercise hereof, including without limitation, the Beneficial Ownership Limitation) immediately before the date of which a
record is taken for such Distribution, or, if no such record is taken, the date as of which the record holders of shares of Common
Stock are to be determined for the participation in such Distribution (provided, however, to the extent that the
Holder's right to participate in any such Distribution would result in the Holder exceeding the Beneficial Ownership Limitation,
then the Holder shall not be entitled to participate in such Distribution to such extent (or in the beneficial ownership of any
shares of Common Stock as a result of such Distribution to such extent) and the portion of such Distribution shall be held in
abeyance for the benefit of the Holder until such time, if ever, as its right thereto would not result in the Holder exceeding
the Beneficial Ownership Limitation).


 




    	 	8	 



     


    

 


e)       Fundamental
Transaction. If, at any time while this Warrant is outstanding, (i) the Company, directly or indirectly, in one or more related
transactions effects any merger or consolidation of the Company with or into another Person, (ii) the Company, directly or indirectly,
effects any sale, lease, license, assignment, transfer, conveyance or other disposition of all or substantially all of its assets
in one or a series of related transactions, (iii) any, direct or indirect, purchase offer, tender offer or exchange offer (whether
by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to sell, tender or exchange
their shares for other securities, cash or property and has been accepted by the holders of 50% or more of the outstanding Common
Stock, (iv) the Company, directly or indirectly, in one or more related transactions effects any reclassification, reorganization
or recapitalization of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted
into or exchanged for other securities, cash or property, or (v) the Company, directly or indirectly, in one or more related transactions
consummates a stock or share purchase agreement or other business combination (including, without limitation, a reorganization,
recapitalization, spin-off or scheme of arrangement) with another Person or group of Persons whereby such other Person or group
acquires more than 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the other Person
or other Persons making or party to, or associated or affiliated with the other Persons making or party to, such stock or share
purchase agreement or other business combination) (each a “Fundamental Transaction”), then, upon any subsequent
exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have been issuable upon
such exercise immediately prior to the occurrence of such Fundamental Transaction, at the option of the Holder (without regard
to any limitation in Section 2(e) on the exercise of this Warrant), the number of shares of Common Stock of the successor or acquiring
corporation or of the Company, if it is the surviving corporation, and any additional consideration (the “Alternate Consideration”)
receivable as a result of such Fundamental Transaction by a holder of the number of shares of Common Stock for which this Warrant
is exercisable immediately prior to such Fundamental Transaction (without regard to any limitation in Section 2(e) on the exercise
of this Warrant). For purposes of any such exercise, the determination of the Exercise Price shall be appropriately adjusted to
apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common
Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among the Alternate Consideration in
a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common
Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder
shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such
Fundamental Transaction. Notwithstanding anything to the contrary, in the event of a Fundamental Transaction, the Company or any
Successor Entity (as defined below) shall, at the Holder’s option, exercisable at any time concurrently with, or within
30 days after, the consummation of the Fundamental Transaction, purchase this Warrant from the Holder by paying to the Holder
an amount of cash equal to the Black Scholes Value of the remaining unexercised portion of this Warrant on the date of the consummation
of such Fundamental Transaction. “Black Scholes Value” means the value of this Warrant based on the Black and
Scholes Option Pricing Model obtained from the “OV” function on Bloomberg, L.P. (“Bloomberg”) determined
as of the day of consummation of the applicable Fundamental Transaction for pricing purposes and reflecting (A) a risk-free interest
rate corresponding to the U.S. Treasury rate for a period equal to the time between the date of the public announcement of the
applicable Fundamental Transaction and the Termination Date, (B) an expected volatility equal to the greater of 100% and the 100
day volatility obtained from the HVT function on Bloomberg as of the Trading Day immediately following the public announcement
of the applicable Fundamental Transaction, (C) the underlying price per share used in such calculation shall be the sum of the
price per share being offered in cash, if any, plus the value of any non-cash consideration, if any, being offered in such Fundamental
Transaction and (D) a remaining option time equal to the time between the date of the public announcement of the applicable Fundamental
Transaction and the Termination Date. The payment of the Black Scholes Value will be made by wire transfer of immediately available
funds within five Business Days of the Holder’s election (or, if later, on the effective date of the Fundamental Transaction).
The Company shall cause any successor entity in a Fundamental Transaction in which the Company is not the survivor (the “Successor
Entity”) to assume in writing all of the obligations of the Company under this Warrant and the other Transaction Documents
in accordance with the provisions of this Section 3(e) pursuant to written agreements in form and substance reasonably satisfactory
to the Holder and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction and shall, at the
option of the Holder, deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced by a written
instrument substantially similar in form and substance to this Warrant which is exercisable for a corresponding number of shares
of capital stock of such Successor Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable
upon exercise of this Warrant (without regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction,
and with an exercise price which applies the exercise price hereunder to such shares of capital stock (but taking into account
the relative value of the shares of Common Stock pursuant to such Fundamental Transaction and the value of such shares of capital
stock, such number of shares of capital stock and such exercise price being for the purpose of protecting the economic value of
this Warrant immediately prior to the consummation of such Fundamental Transaction), and which is reasonably satisfactory in form
and substance to the Holder. Upon the occurrence of any such Fundamental Transaction, the Successor Entity shall succeed to, and
be substituted for (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant and the other
Transaction Documents referring to the “Company” shall refer instead to the Successor Entity), and may exercise every
right and power of the Company and shall assume all of the obligations of the Company under this Warrant and the other Transaction
Documents with the same effect as if such Successor Entity had been named as the Company herein.


 




    	 	9	 



     


    

 


f)      Calculations.
All calculations under this Section 3 shall be made to the nearest cent or the nearest 1/100th of a share, as the case may be.
For purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall
be the sum of the number of shares of Common Stock (excluding treasury shares, if any) issued and outstanding.


 


g)      Notice
to Holder.


 


i.       Adjustment
to Exercise Price. Whenever the Exercise Price is adjusted pursuant to any provision of this Section 3, the Company shall
promptly deliver to the Holder by facsimile or email a notice setting forth the Exercise Price after such adjustment and any resulting
adjustment to the number of Warrant Shares and setting forth a brief statement of the facts requiring such adjustment.


 


ii.       Notice
to Allow Exercise by Holder. If (A) the Company shall declare a dividend (or any other distribution in whatever form) on the
Common Stock, (B) the Company shall declare a special nonrecurring cash dividend on or a redemption of the Common Stock, (C) the
Company shall authorize the granting to all holders of the Common Stock rights or warrants to subscribe for or purchase any shares
of capital stock of any class or of any rights, (D) the approval of any stockholders of the Company shall be required in connection
with any reclassification of the Common Stock, any consolidation or merger to which the Company is a party, any sale or transfer
of all or substantially all of the assets of the Company, or any compulsory share exchange whereby the Common Stock is converted
into other securities, cash or property, or (E) the Company shall authorize the voluntary or involuntary dissolution, liquidation
or winding up of the affairs of the Company, then, in each case, the Company shall cause to be delivered by facsimile or email
to the Holder at its last facsimile number or email address as it shall appear upon the Warrant Register of the Company, at least
20 calendar days prior to the applicable record or effective date hereinafter specified, a notice stating (x) the date on which
a record is to be taken for the purpose of such dividend, distribution, redemption, rights or warrants, or if a record is not
to be taken, the date as of which the holders of the Common Stock of record to be entitled to such dividend, distributions, redemption,
rights or warrants are to be determined or (y) the date on which such reclassification, consolidation, merger, sale, transfer
or share exchange is expected to become effective or close, and the date as of which it is expected that holders of the Common
Stock of record shall be entitled to exchange their shares of the Common Stock for securities, cash or other property deliverable
upon such reclassification, consolidation, merger, sale, transfer or share exchange; provided that the failure to deliver such
notice or any defect therein or in the delivery thereof shall not affect the validity of the corporate action required to be specified
in such notice. To the extent that any notice provided in this Warrant constitutes, or contains, material, non-public information
regarding the Company or any of the Subsidiaries, the Company shall simultaneously file such notice with the Commission pursuant
to a Current Report on Form 8-K. The Holder shall remain entitled to exercise this Warrant during the period commencing on the
date of such notice to the effective date of the event triggering such notice except as may otherwise be expressly set forth herein.


 




    	 	10	 



     


    

 


Section 4.         Transfer
of Warrant.


 


a)       Transferability.
Pursuant to FINRA Rule 5110(g)(1), neither this Warrant nor any Warrant Shares issued
upon exercise of this Warrant shall be sold, transferred, assigned, pledged or hypothecated, or be the subject of any hedging,
short sale, derivative, put or call transaction that would result in the effective economic disposition of the securities by any
person for a period of 180 days immediately following the date of effectiveness or commencement of sales of the offering pursuant
to which this Warrant is being issued, except the transfer of any security:


 


		(i)	by operation
of law or by reason of reorganization of the Company;



 


		(ii)	to
                                         any FINRA member firm participating in the offering and the officers and partners thereof,
                                         if all securities so transferred remain subject to the lock-up restriction in this Section
                                         4(a) for the remainder of the time period;



 


		(iii)	if
                                         the aggregate amount of securities of the Company held by the Holder or related person
                                         do not exceed 1% of the securities being offered;



 


		(iv)	that
                                         is beneficially owned on a pro-rata basis by all equity owners of an investment fund,
                                         provided that no participating member manages or otherwise directs investments by the
                                         fund, and participating members in the aggregate do not own more than 10% of the equity
                                         in the fund; or 



 


		(v)	the
                                         exercise or conversion of any security, if all securities received remain subject to
                                         the lock-up restriction in this Section 4(a) for the remainder of the time period.



 


Subject
to the foregoing restriction, this Warrant and all rights hereunder (including, without limitation, any registration rights)
are transferable, in whole or in part, upon surrender of this Warrant at the principal office of the Company or its designated
agent, together with a written assignment of this Warrant substantially in the form attached hereto duly executed by the Holder
or its agent or attorney and funds sufficient to pay any transfer taxes payable upon the making of such transfer. Upon such surrender
and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants in the name of the assignee or
assignees, as applicable, and in the denomination or denominations specified in such instrument of assignment, and shall issue
to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant shall promptly be cancelled.
Notwithstanding anything herein to the contrary, the Holder shall not be required to
physically surrender this Warrant to the Company unless the Holder has assigned this Warrant in full, in which case, the Holder
shall surrender this Warrant to the Company within three (3) Trading Days of the date the Holder delivers an assignment form to
the Company assigning this Warrant in full. The Warrant, if properly assigned in accordance herewith, may be exercised
by a new holder for the purchase of Warrant Shares without having a new Warrant issued.


 




    	 	11	 



     


    

 


b)       New
Warrants. This Warrant may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of
the Company, together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed
by the Holder or its agent or attorney. Subject to compliance with Section 4(a), as to any transfer which may be involved in such
division or combination, the Company shall execute and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants
to be divided or combined in accordance with such notice. All Warrants issued on transfers or exchanges shall be dated the Issue
Date and shall be identical with this Warrant except as to the number of Warrant Shares issuable pursuant thereto.


 


c)       Warrant
Register. The Company shall register this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant
Register”), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered
Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder,
and for all other purposes, absent actual notice to the contrary.


 


Section 5.         Miscellaneous.


 


a)       No
Rights as Stockholder Until Exercise. This Warrant does not entitle the Holder to any voting rights, dividends or other rights
as a stockholder of the Company prior to the exercise hereof as set forth in Section 2(d)(i), except as expressly set forth in
Section 3.


 


b)       Loss,
Theft, Destruction or Mutilation of Warrant. The Company covenants that upon receipt by the Company of evidence reasonably
satisfactory to it of the loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant
Shares, and in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to it (which, in the case
of the Warrant, shall not include the posting of any bond), and upon surrender and cancellation of such Warrant or stock certificate,
if mutilated, the Company will make and deliver a new Warrant or stock certificate of like tenor and dated as of such cancellation,
in lieu of such Warrant or stock certificate.


 


c)       Saturdays,
Sundays, Holidays, etc. If the last or appointed day for the taking of any action or the expiration of any right required
or granted herein shall not be a Business Day, then, such action may be taken or such right may be exercised on the next succeeding
Business Day.


 




    	 	12	 



     


    

 


d)       Authorized
Shares.


 


The Company covenants
that, during the period the Warrant is outstanding, it will reserve from its authorized and unissued Common Stock a sufficient
number of shares to provide for the issuance of the Warrant Shares upon the exercise of any purchase rights under this Warrant.
The Company further covenants that its issuance of this Warrant shall constitute full authority to its officers who are charged
with the duty of issuing the necessary Warrant Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such Warrant Shares may be issued as provided herein without
violation of any applicable law or regulation, or of any requirements of the Trading Market upon which the Common Stock may be
listed. The Company covenants that all Warrant Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase rights represented by this Warrant and payment for such Warrant Shares in
accordance herewith, be duly authorized, validly issued, fully paid and nonassessable and free from all taxes, liens and charges
created by the Company in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue).


 


Except and to
the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation, amending
its certificate of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue
or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms
of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such
actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without
limiting the generality of the foregoing, the Company will (i) not increase the par value of any Warrant Shares above the amount
payable therefor upon such exercise immediately prior to such increase in par value, (ii) take all such action as may be necessary
or appropriate in order that the Company may validly and legally issue fully paid and nonassessable Warrant Shares upon the exercise
of this Warrant and (iii) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any
public regulatory body having jurisdiction thereof, as may be, necessary to enable the Company to perform its obligations under
this Warrant.


 


Before taking
any action which would result in an adjustment in the number of Warrant Shares for which this Warrant is exercisable or in the
Exercise Price, the Company shall obtain all such authorizations or exemptions thereof, or consents thereto, as may be necessary
from any public regulatory body or bodies having jurisdiction thereof.


 


e)       Jurisdiction.
All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be determined in accordance
with the provisions of the Purchase Agreement.


 


f)       Restrictions.
The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if not registered, and the Holder
does not utilize cashless exercise, will have restrictions upon resale imposed by state and federal securities laws.


 




    	 	13	 



     


    

 


g)       Nonwaiver
and Expenses. No course of dealing or any delay or failure to exercise any right hereunder on the part of Holder shall operate
as a waiver of such right or otherwise prejudice the Holder’s rights, powers or remedies, notwithstanding the fact that
all rights hereunder terminate on the Termination Date. If the Company willfully and knowingly fails to comply with any provision
of this Warrant, which results in any material damages to the Holder, the Company shall pay to the Holder such amounts as shall
be sufficient to cover any costs and expenses including, but not limited to, reasonable attorneys’ fees, including those
of appellate proceedings, incurred by the Holder in collecting any amounts due pursuant hereto or in otherwise enforcing any of
its rights, powers or remedies hereunder.


 


h)       Notices.
Any notice, request or other document required or permitted to be given or delivered to the Holder by the Company shall be delivered
in accordance with the notice provisions of the Purchase Agreement.


 


i)       Limitation
of Liability. No provision hereof, in the absence of any affirmative action by the Holder to exercise this Warrant to purchase
Warrant Shares, and no enumeration herein of the rights or privileges of the Holder, shall give rise to any liability of the Holder
for the purchase price of any Common Stock or as a stockholder of the Company, whether such liability is asserted by the Company
or by creditors of the Company.


 


j)       Remedies.
The Holder, in addition to being entitled to exercise all rights granted by law, including recovery of damages, will be entitled
to specific performance of its rights under this Warrant. The Company agrees that monetary damages would not be adequate compensation
for any loss incurred by reason of a breach by it of the provisions of this Warrant and hereby agrees to waive and not to assert
the defense in any action for specific performance that a remedy at law would be adequate.


 


k)       Successors
and Assigns. Subject to applicable securities laws, this Warrant and the rights and obligations evidenced hereby shall inure
to the benefit of and be binding upon the successors and permitted assigns of the Company and the successors and permitted assigns
of Holder. The provisions of this Warrant are intended to be for the benefit of any Holder from time to time of this Warrant and
shall be enforceable by the Holder or holder of Warrant Shares.


 


l)       Amendment.
This Warrant may be modified or amended or the provisions hereof waived with the written consent of the Company and the Holder.


 


m)      Severability.
Wherever possible, each provision of this Warrant shall be interpreted in such manner as to be effective and valid under applicable
law, but if any provision of this Warrant shall be prohibited by or invalid under applicable law, such provision shall be ineffective
to the extent of such prohibition or invalidity, without invalidating the remainder of such provisions or the remaining provisions
of this Warrant.


 


n)       Headings.
The headings used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of
this Warrant.


 


********************


 


(Signature Page Follows)


 




    	 	14	 



     


    

 


IN WITNESS WHEREOF, the
Company has caused this Warrant to be executed by its officer thereunto duly authorized as of the date first above indicated.


 


	 	Biostage, Inc.
	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:



 




    	 	15	 



     


    

 


NOTICE OF EXERCISE


 


		To:	Biostage, Inc.



 


(1)   The
undersigned hereby elects to purchase ________ Warrant Shares of the Company pursuant to the terms of the attached Warrant (only
if exercised in full), and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes,
if any.


 


(2)   Payment
shall take the form of (check applicable box):


 





 ̈
in lawful money of the United States; or


 


 ̈
[if permitted the cancellation of such number of Warrant Shares as is necessary, in accordance with the formula set forth in subsection
2(c), to exercise this Warrant with respect to the maximum number of Warrant Shares purchasable pursuant to the cashless exercise
procedure set forth in subsection 2(c).




 


(3)   Please
issue said Warrant Shares in the name of the undersigned or in such other name as is specified below:


 


_______________________________


  


The Warrant Shares shall be delivered to the
following DWAC Account Number:


 


_______________________________


 


_______________________________


 


_______________________________


 


[SIGNATURE
OF HOLDER]


 


	Name of Investing Entity:	 





	Signature of Authorized Signatory of Investing Entity:	 





	Name of Authorized Signatory:	 





	Title of Authorized Signatory:	 





	Date:	 


 




     

     


    

 


EXHIBIT B


 


ASSIGNMENT
FORM


(To assign the foregoing Warrant, execute
this form and supply required information. Do not use this form to purchase shares.)


 


FOR VALUE RECEIVED, the foregoing Warrant
and all rights evidenced thereby are hereby assigned to


 


	Name:	 	 
	 	(Please Print)	 
	 	 	 
	Address:	 	 
	 	(Please Print)	 
	 	 	 
	Phone Number:	 	 
	 	 	 
	Email Address: 	 	 


 


Dated: _______________ __, ______


 


Holder’s Signature:___________________


 


Holder’s Address: ___________________