Exhibit 10.16  NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH
THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND
EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON
AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE SECURITIES ACT), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD
EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT
OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO,
THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH
APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO
THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY
ACCEPTABLE TO THE COMPANY.  ,
2008WG-  COMMON STOCK PURCHASE WARRANT  To Purchase
                  
Shares of Common Stock of  CALLISTO
PHARMACEUTICALS, INC.  THIS COMMON STOCK
PURCHASE WARRANT (the Warrant) certifies that, for value received,
                        
(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 date hereof (the Initial Exercise Date) and on or
prior to the close of business on December 31, 2016 (the Termination
Date) but not thereafter, to subscribe for and purchase from Callisto
Pharmaceuticals, Inc., a Delaware corporation (the Company), up
to shares (the Warrant Shares) of Common Stock, par value
$.0001 per share, of the Company (the 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 part of an authorized class
of up to 57,500,000 warrants of like tenor.  Section 1.Definitions.  Capitalized
terms used and not otherwise defined herein shall have the meanings set forth
in that certain Securities Purchase and Exchange Agreement (the Purchase
Agreement), dated December 30, 2008, 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 at any time or times on or after
the Initial Exercise Date and on or before the Termination Date by delivery to
the Company of a duly executed facsimile copy of the Notice of Exercise Form annexed
hereto (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 such Holder
appearing on the books of the Company);  provided, however, within
5 Trading Days of the date said Notice of Exercise is delivered to the Company,


the Holder shall
have surrendered this Warrant to the Company and the Company shall have
received payment of the aggregate Exercise Price of the shares thereby
purchased by wire transfer or cashiers check drawn on a United States bank.  b)Exercise Price.  The exercise price of the Common Stock under
this Warrant shall be $0.02, subject
to adjustment hereunder (the Exercise Price).  c)Net
Exercise.  If at any time there is no
effective Registration Statement registering, or no current prospectus
available for, the resale of the Warrant Shares by the Holder, then this
Warrant may also be exercised at such time by means of a cashless exercise in
which the Holder shall be entitled to receive a certificate for the number of
Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A),
where:  (A) = the volume weighted average trading price
of the Common Stock on the principal the principal market in upon which the
Common Stock may be listed or is traded (the Trading Market) over the twenty
(20) consecutive Trading Days immediately preceding the date of such election (VWAP);  (B) =  the
Exercise Price of this Warrant, as adjusted; and  (X) = the number of Warrant Shares issuable upon
exercise of this Warrant in accordance with the terms of this Warrant by means
of a cash exercise rather than a cashless exercise.  d)Exercise
Limitations.  The Holder shall not have the right to exercise any
portion of this Warrant, pursuant to Section 2(c) or otherwise, to
the extent that after giving effect to such issuance after exercise, the Holder
(together with the Holders affiliates), as set forth on the applicable Notice
of Exercise, would beneficially own in excess of 4.99% of the number of shares
of the Common Stock outstanding immediately after giving effect to such
issuance.  For purposes of the foregoing sentence, the number of shares of
Common Stock beneficially owned by the Holder and its affiliates shall include
the number of shares of Common Stock issuable upon exercise of this Warrant and
any other security of the Company convertible into Common Stock with respect to
which the determination of such sentence is being made.  Except as set
forth in the preceding sentence, for purposes of this Section 2(d),
beneficial ownership shall be calculated in accordance with Section 13(d) of
the Exchange Act, it being acknowledged by Holder that the Company is not
representing to Holder that such calculation is in compliance with Section 13(d) of
the Exchange Act and 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(d) applies,
the determination of whether this Warrant is exercisable (in relation to other
securities owned by the Holder) and of which portion of this Warrant is
exercisable shall be in the sole discretion of such Holder, and the


submission of a Notice of Exercise shall be deemed to
be such Holders determination of whether this Warrant is exercisable (in
relation to other securities owned by such Holder) and of which portion of this
Warrant is exercisable, in each case subject to such aggregate percentage
limitation, and the Company shall have no obligation to verify or confirm the
accuracy of such determination.  For
purposes of this Section 2(d), in determining the number of outstanding
shares of Common Stock, the Holder may rely on the number of outstanding shares
of Common Stock as reflected in (x) the Companys most recent Form 10-Q
or Form 10-K, as the case may be, (y) a more recent public
announcement by the Company or (z) any other notice by the Company or the
Companys Transfer Agent setting forth the number of shares of Common Stock
outstanding.  Upon the written or oral request of the 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 since the date as of which such
number of outstanding shares of Common Stock was reported.  The provisions of this Section 2(d) may
be waived by the Holder upon, at the election of the Holder, not less than 61
days prior notice to the Company, and the provisions of this Section 2(d) shall
continue to apply until such 61st day (or such later date, as determined by the
Holder, as may be specified in such notice of waiver).  e)Mechanics
of Exercise.  i.Authorization
of Warrant Shares.  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, be duly authorized, validly issued, fully
paid and nonassessable and free from all taxes, liens and charges in respect of
the issue thereof (other than taxes in respect of any transfer occurring
contemporaneously with such issue).  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
executing stock certificates to execute and issue the necessary certificates
for the 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.


ii.Delivery
of Certificates Upon Exercise. 
Certificates for shares purchased hereunder shall be transmitted by the
transfer agent of the Company to the Holder by crediting the account of the
Holders prime broker with the Depository Trust Company through its Deposit
Withdrawal Agent Commission (DWAC) system if the Company is a
participant in such system, and otherwise by physical delivery to the address
specified by the Holder in the Notice of Exercise within 3 Trading Days from
the delivery to the Company of the Notice of Exercise Form, surrender of this
Warrant and payment of the aggregate Exercise Price as set forth above (Warrant
Share Delivery Date).  This Warrant
shall be deemed to have been exercised on the date the Exercise Price is
received by the Company.  The Warrant
Shares shall be deemed to have been issued, and Holder or any other person so
designated to be named therein shall be deemed to have become a holder of
record of such shares for all purposes, as of the date the Warrant has been
exercised by payment to the Company of the Exercise Price and all taxes
required to be paid by the Holder, if any, prior to the issuance of such
shares, have been paid.  iii.Delivery
of New Warrants Upon Exercise.  If
this Warrant shall have been exercised in part, the Company shall, at the time
of delivery of the certificate or certificates representing Warrant Shares,
deliver to Holder a new Warrant evidencing the rights of 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.  iv.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 Holder would otherwise be entitled to purchase upon
such exercise, the Company shall pay a cash adjustment in respect of such final
fraction in an amount equal to such fraction multiplied by the Exercise Price.  v.Charges,
Taxes and Expenses.  Issuance of
certificates for 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 certificate, all of which taxes and expenses shall be paid by
the Company, and such certificates 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 certificates for 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.


vi.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.  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 pursuant to 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 before such event and of which the denominator
shall be the number of shares of Common Stock outstanding after such event and
the number of shares issuable upon exercise of this Warrant shall be
proportionately adjusted. 
Notwithstanding the forgoing, in the event an adjustment under
paragraphs 3(a)(iii) or (iv) would result in an Exercise Price
greater than $0.02, following the calculation of the number of shares issuable
as adjusted, the Exercise Price shall thereafter be fixed at $0.04.  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.  b)Redemption.  Beginning twelve (12) months after the
Initial Exercise Date, provided the Equity Conditions, defined below, are
satisfied, if the daily closing price of the Common Stock equals $1.00 or more
(subject to adjustment for stock splits, reclassifications, combinations and
similar adjustments) per share for the 20 consecutive Trading Days (such calculation
to occur no earlier than twelve (12) months after the Initial Exercise Date)
immediately prior to the Redemption Notice Date (as defined below), and average
daily dollar volume of the Common Stock on the Trading Market is at least
$1,000,000, unless the Holder is prohibited from exercising the Warrants
pursuant to Section 1(d)(i) hereof, the Company shall have the right,
on twenty (20) business days notice to the Holder (an Redemption Notice
and the date such notice is received by the Holder, the Redemption Notice
Date), to redeem any portion of the Warrants then held by the Holder for
$0.001 per Warrant. To effect a Redemption hereunder, the Holder shall not be
required to physically surrender the Warrant certificate to the Company.  Equity Conditions shall mean, during
the period in question, (i) the Company


shall have duly
honored all Warrant exercises scheduled to occur or occurring by virtue of one
or more Notices of Exercise, if any, (ii) there is an effective
Registration Statement pursuant to which the Holder is permitted to utilize the
prospectus thereunder to resell all of the shares issuable pursuant to the
Transaction Documents (and the Company believes, in good faith, that such
effectiveness will continue uninterrupted for the foreseeable future), (iii) the
Common Stock is trading on the Trading Market and all of the shares issuable
pursuant to the Transaction Documents are listed for trading on a Trading
Market (and the Company believes, in good faith, that trading of the Common Stock
on a Trading Market will continue uninterrupted for the foreseeable future), (iv) there
is a sufficient number of authorized but unissued and otherwise unreserved
shares of Common Stock for the issuance of all of the shares issuable pursuant
to the Transaction Documents, and (v) no public announcement of a pending
or proposed Fundamental Transaction, Change of Control Transaction or
acquisition transaction has occurred that has not been consummated.  c)Subsequent Equity
Sales. Other than pursuant to an Exempt Issuance, for the period commencing
on the date this warrant is originally issued until June 30, 2010, if the
Company shall sell or grant any option to purchase or otherwise dispose of or
issue any Common Stock or Common Stock Equivalents entitling any Person to
acquire shares of Common Stock, at an effective price per share less than the
then Exercise Price (such lower price, the Base Share Price and such
issuances collectively, a Dilutive Issuance), as adjusted hereunder
(if the holder of the Common Stock or Common Stock Equivalents so issued shall
at any time, whether by operation of purchase price adjustments, reset
provisions, floating conversion, exercise or exchange prices or otherwise, or
due to warrants, options or rights per share which is issued in connection with
such issuance, be entitled to receive shares of Common Stock at an effective
price per share which is less than the Exercise Price, such issuance shall be
deemed to have occurred for less than the Exercise Price), then, the Exercise
Price shall be reduced then to an amount equal to the Base Share Price. Such
adjustment shall be made whenever such Common Stock or Common Stock Equivalents
are issued.  The Company shall notify the
Holder in writing, no later than the Trading Day following the issuance of any
Common Stock or Common Stock Equivalents subject to this section, indicating
therein the applicable issuance price, or of applicable reset price, exchange
price, conversion price and other pricing terms (such notice the Dilutive
Issuance Notice).  For purposes of
clarification, whether or not the Company provides a Dilutive Issuance Notice
pursuant to this Section 3(b), upon the occurrence of any Dilutive
Issuance, after the date of such Dilutive Issuance the Holder is entitled to
purchase number of Warrant Shares determined by dividing the product of the
Exercise Price and the number of Warrant Shares which could be obtained upon
the exercise of the Warrants prior to such adjustment by the Base Share Price
regardless of whether the Holder accurately refers to the Base Share Price in
the Notice of Exercise.


d)Pro Rata
Distributions.  If the Company, at
any time prior to the Termination Date, shall distribute to all holders of
Common Stock (and not to Holders of the Warrants) evidences of its indebtedness
or assets or rights or warrants to subscribe for or purchase any security other
than the Common Stock, then in each such case the Exercise Price shall be
adjusted by multiplying the Exercise Price in effect immediately prior to the
record date fixed for determination of stockholders entitled to receive such
distribution by a fraction of which the denominator shall be the VWAP
determined as of the record date mentioned above, and of which the numerator
shall be such VWAP on such record date less the then per share fair market
value at such record date of the portion of such assets or evidence of
indebtedness so distributed applicable to one outstanding share of the Common
Stock as determined by the Board of Directors in good faith.  In either case the adjustments shall be
described in a statement provided to the Holders of the portion of assets or
evidences of indebtedness so distributed or such subscription rights applicable
to one share of Common Stock.  Such
adjustment shall be made whenever any such distribution is made and shall
become effective immediately after the record date mentioned above.  e)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. The number of shares of
Common Stock outstanding at any given time shall not includes shares of Common
Stock owned or held by or for the account of the Company, and the description
of any such shares of Common Stock shall be considered on issue or sale of
Common Stock.  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.  f)Notice to
Holders.  i.Adjustment
to Exercise Price. Whenever the Exercise Price is adjusted pursuant to this
Section 3, the Company shall promptly mail to each Holder a notice setting
forth the Exercise Price after such adjustment 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) 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, of any compulsory share exchange whereby the Common
Stock is converted into


other securities,
cash or property; (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 mailed to the Holder
at its last addresses as it shall appear upon the Warrant Register of the
Company, at least 10 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 mail such notice or any defect therein or in the mailing thereof
shall not affect the validity of the corporate action required to be specified
in such notice.  The Holder is entitled
to exercise this Warrant during the 10-day period commencing the date of such
notice to the effective date of the event triggering such notice.  g)Reorganizations, Etc.   In case,
at any time during the Exercise Period, of any capital reorganization, of any
reclassification of the stock of the Company (other than a change in par value
or from par value to no par value or from no par value to par value or as a
result of a stock dividend or subdivision, split-up or combination of shares),
or the consolidation or merger of the Company with or into another corporation
(other than a consolidation or merger in which the Company is the continuing
operation and which does not result in any change or reclassification in the
Warrant Shares) or of the sale of all or substantially all the properties and
assets of the Company as an entirety to any other corporation, the Company, at
its sole discretion, shall have the right and option to (A) provide 30
days prior written notice of such event to the Holder and this Warrant shall
terminate and be of no further force and effect on and after the effective date
of such capital reorganization or reclassification or the consummation of such
consolidation, sale or merger; or (B) provide that this Warrant shall,
after such reorganization, reclassification, consolidation, merger or sale, be
exercisable for the kind and number of shares of stock or other securities or
property of the Company or of the corporation resulting from such consolidation
or surviving such merger or to which such properties and assets shall have been
sold to which such holder would have been entitled if he, she or it had held
the Warrant Shares issuable upon the exercise hereof immediately prior to such
reorganization, reclassification, consolidation, merger or sale.


h)Exempt Issuance.
Exempt Issuance means the issuance of (i) shares of Common Stock
or options to employees, officers, directors or bona fide consultants of the
Company (including shares of Common Stock issued pursuant to the exercise of
such options) pursuant to any stock or option plan duly adopted by a majority
of the non-employee members of the Board of Directors of the Company or a
majority of the members of a committee of non-employee directors established
for such purpose, (ii) securities issued upon the exercise or exchange of
or conversion of any Securities issued hereunder and/or securities exercisable
or exchangeable for or convertible into shares of Common Stock issued and
outstanding on the date of this Warrant was originally issued, provided that
such securities have not been amended since the date this Warrant was
originally issued to increase the number of such securities or to decrease the
exercise, exchange or conversion price of any such securities, (c) securities
issued in lieu of cash payments for bona fide license fees or royalties,  (d) securities issued in a single
financing transaction for cash in an amount less than $100,000  or in a series of financing transaction
occurring over a period of 60 consecutive day in an amount less than $100,000,
and (e) securities issued pursuant to acquisitions or strategic
transactions approved by a majority of the disinterested directors, provided
any such issuance shall only be to a Person which is, itself or through its
subsidiaries, an operating company in a business synergistic with the business
of the Company and in which the Company receives benefits in addition to the
investment of funds, but shall not include a transaction in which the Company
is issuing securities primarily for the purpose of raising capital or to an
entity whose primary business is investing in securities,  i)Voluntary
Adjustment By Company. The Company may at any time during the term of this
Warrant reduce the then current Exercise Price to any amount and for any period
of time deemed appropriate by the Board of Directors of the Company.  Section 4.               Transfer
of Warrant.  a)Transferability.  Subject to compliance with any applicable
securities laws and the conditions set forth in Sections 5(a) and 4(d) hereof
and to the provisions of Section 4.1 of the Purchase Agreement, this
Warrant and all rights hereunder are transferable, in whole or in part, upon
surrender of this Warrant at the principal office of the Company, 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 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.  A


Warrant, if
properly assigned, may be exercised by a new holder for the purchase of Warrant
Shares without having a new Warrant issued.  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.  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.  d)Transfer
Restrictions. If, at the time of the surrender of this Warrant in
connection with any transfer of this Warrant, the transfer of this Warrant
shall not be registered pursuant to an effective registration statement under
the Securities Act and under applicable state securities or blue sky laws, the
Company may require, as a condition of allowing such transfer (i) that the
Holder or transferee of this Warrant, as the case may be, furnish to the
Company a written opinion of counsel (which opinion shall be in form, substance
and scope customary for opinions of counsel in comparable transactions) to the
effect that such transfer may be made without registration under the Securities
Act and under applicable state securities or blue sky laws, (ii) that the
holder or transferee execute and deliver to the Company an investment letter in
form and substance acceptable to the Company and (iii) that the transferee
be an accredited investor as defined in Rule 501(a)(1), (a)(2), (a)(3),
(a)(7), or (a)(8) promulgated under the Securities Act or a qualified institutional
buyer as defined in Rule 144A(a) under the Securities Act.  Section 5.               Registration Rights.  a)             Joining other Registration
Statements.            If at any time
or times, the Company proposes to file one or more Registration Statements on Form S-1
or S-3 or other appropriate form for the registration of its Common Stock or
other equity securities under the Securities Act for a public offering, whether
or not underwritten (excluding the issuance of shares pursuant to employees
options, incentive or similar plans, or in connection with an acquisition,
merger or exchange of securities which involves no distribution for cash), it
shall give a Notice of Registration to the Holder and shall include in each
Registration Statement referred to in such notice all such Warrant Shares with
respect to which the Holder shall have delivered to the Company a Notice of


Intent to Sell within 20
days after the Company has given its Notice of Registration.   Such Notice of Registration shall be given
not later than ten (10) days prior to the filing of any such Registration
Statement.   All expenses incurred by the
Company in complying with the foregoing registration requirements (except fees
and disbursements of counsel for the Holder; registration fees of the
Commission for registration of the Securities, underwriting discounts,
commissions or similar expenses to be incurred in connection with the sale of
securities to be registered for the Holder) shall be borne by the Company.  The Company shall have no obligation to register
any Securities under this Section 5(a) unless the Holder agrees to
join in the underwriting arrangements, 
if any, proposed for the other securities being registered on the same
terms as other participants in the distribution, unless such underwriters decline
to include the Warrant Shares therein in which event the Company may delay the
delivery of prospectuses to the Holder for a period not in excess of 45 days
from the effective date of such Registration Statement.  The foregoing rights of registration shall be
applicable on one, and only one occasion, regardless of the number of shares
included therein, provided that the Registration statement shall have become
effective and shall remain effective and in compliance with the Securities Act,
subject to the limitations of Section 5(b)   The Holders rights pursuant to this Section 5(a) 
shall expire on December 31, 2011.  b)            Notice of Intent to Sell and
Notice of Registration.  Notice of
Intent to Sell shall mean a written notice signed by the Holder (i) setting
forth the number of units of Warrant Shares which the Holder desires to have
registered for sale, (ii) representing that the Holder has a present
intention to sell the same, (iii) setting forth (if delivered pursuant to Section 5(a))
the intended method by which such sale will be effected and the names of the
underwriters, if any; whose services are intended to be used to effect such
sale, and (iv) agreeing to execute all consents, powers of attorneys,
registration statements, and other documents required in order to permit such
Registration Statement to be made effective and carry out the
distribution.  Notice of Registration
shall mean a written notice signed by an officer of the Company and setting
forth the approximate date on which it intends to file a Registration Statement
on Form, S-1 or S-3 or other appropriate form for the registration of its
Common Stock pursuant to the Securities Act, and the approximate date on which
it contemplates such Registration Statement will become effective whether the
Registration Statement is being filed pursuant to Section 5(a) of
this Warrant.  c)             Indemnification.  The obligation of the Company to register
Warrant Shares for the Holder pursuant to this Agreement shall be subject to
the receipt by the Company of an agreement from the Holder and each underwriter
of any securities registered for the Holder, in form and substance satisfactory
to the Company,  indemnifying the Company
against liability arising out of or based upon any untrue statement or alleged untrue
statement of a material fact in the Registration statement or the omission or
alleged omission to state therein any material fact required to be stated
therein or necessary in order to make the statements therein not misleading, if
such statement or omission was made by the Company in reliance upon and in
conformity with written information furnished to the Company specifically. for
use in such Registration Statement by or on behalf of the Holder with respect
to the Holder or any underwriter of any securities registered for the
Holder.  In connection with registration
under the


Securities Act of
securities owned by the Holder,  the
Company hereby agrees to indemnify the Holder and each underwriter of any
securities registered for the Holder against liability arising out of or based
upon any untrue statement or alleged untrue statement of a material fact in a
Registration statement filed by the Company pursuant hereto, or the omission or
alleged omission to state in such Registration Statement any material fact
required to be stated therein or necessary in order to make the statement
therein not misleading, other than any such statement included in, or omission
from, such Registration Statement by the Company in reliance upon and in
conformity with written information furnished to the Company,  specifically for use therein by or on behalf
of the Holder with respect to the Holder or by any underwriter of the
securities included therein and to join in an underwriting agreement having
usual and customary terms, including customary representations warranties and
agreements (in addition to the indemnification agreements provided by this Section 5(c)).  d)            Certain Terms and Conditions.          The following provisions shall be
applicable to all registration rights granted in this Section 5:  i.the
Company shall have the right to require any registration required under Section 5(a) to
contemplate offerings in the same manner as other shares registered therein,
provided they are offerings by way of either (i) firm underwritings, (ii) 
exchange distributions or (iii) shelf registration statements;  ii.the
Company shall not be required to maintain any Registration Statement under Section 5(a) in
effect for a period of more than six months; provided, however,  that this period shall be extended at the
request of the Holder to no more than nine months to meet the requirements of
underwriters of such securities pursuant to the terms of an underwriting
agreement;  iii.the
Company need not include any Warrants or shares owned by the Holder in any
Registration Statement provided for under Sections 5(a) if in the opinion
of counsel for the Company satisfactory to counsel for the Holder, registration
of such shares under the Securities Act is not necessary for the Holder to dispose
of such shares in a public offering and distribution in the open market in
compliance with the Securities Act; provided, in such case the opinion of such
counsel shall be in writing addressed to the Holder and shall be rendered
within twenty (20) days after the Notice of Intent to Sell is received by the
Company.  Section 6.               Miscellaneous.  a)Title
to Warrant.  Prior to the Termination
Date and subject to compliance with applicable laws and Section 4 of this
Warrant, this Warrant and all rights hereunder are transferable, in whole or in
part, at the office or agency of the Company by the Holder in person or by duly
authorized attorney, upon surrender of this Warrant together with the
Assignment Form annexed hereto


properly endorsed. 
The transferee shall sign an investment letter in form and substance
reasonably satisfactory to the Company.  b)No
Rights as Shareholder Until Exercise. 
This Warrant does not entitle the Holder to any voting rights or other
rights as a shareholder of the Company prior to the exercise hereof.  Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price (or by means of a cashless exercise),
the Warrant Shares so purchased shall be and be deemed to be issued to such
Holder as the record owner of such shares as of the close of business on the
later of the date of such surrender or payment.  c)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.  d)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 be a Saturday, Sunday or a legal holiday, then
such action may be taken or such right may be exercised on the next succeeding
day not a Saturday, Sunday or legal holiday.  e)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 executing stock certificates to execute and issue
the necessary certificates for the 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.  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 (a) 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, (b) 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 (c) 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.  f)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.  g)Restrictions.  The Holder acknowledges that the Warrant
Shares acquired upon the exercise of this Warrant, if not registered, will have
restrictions upon resale imposed by state and federal securities laws.  h)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 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 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 Holder in collecting any amounts
due pursuant hereto or in otherwise enforcing any of its rights, powers or
remedies hereunder.  i)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.  j)Limitation
of Liability.  No provision hereof,
in the absence of any affirmative action by Holder to exercise this Warrant or
purchase Warrant Shares, and no enumeration herein of the rights or privileges
of Holder, shall give rise to any liability of 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.  k)Remedies.  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 the defense
in any action for specific performance that a remedy at law would be adequate.  l)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 of the Company
and the successors and permitted assigns of Holder.  The provisions of this Warrant are intended
to be for the benefit of all Holders from time to time of this Warrant and
shall be enforceable by any such Holder or holder of Warrant Shares.  m)Amendment.  This Warrant may be modified or amended or
the provisions hereof waived with the written consent of the Company and the
holders of not less than 70% of the Warrants of like tenor then outstanding as
shown of the books and records of the Company. 
In such event, the Company will promptly mail notice of any such
modification or amendment to all holders of the Warrants that have not
consented thereto.  n)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.  o)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.  ********************


IN WITNESS WHEREOF, the
Company has caused this Warrant to be executed by its officer thereunto duly
authorized.   Dated:  December 30, 2008   CALLISTO PHARMACEUTICALS, INC.By:Name:
  Gary S. JacobTitle:
  CEO


NOTICE OF EXERCISE  TO:         CALLISTO
PHARMACEUTICALS, 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):  o
in lawful money of the United States; or  o
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 a certificate or certificates representing 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:   (4)  Accredited
Investor.  The undersigned is an accredited
investor as defined in Regulation D promulgated under the Securities Act of
1933, as amended.  [SIGNATURE OF
HOLDER]  Name of
  Investing Entity:Signature of Authorized Signatory of Investing Entity:Name of Authorized Signatory:Title of Authorized Signatory:Date:


ASSIGNMENT FORM  (To assign the
foregoing warrant, execute
this form and supply required information. 
Do not use this form to exercise the warrant.)  FOR VALUE RECEIVED, the
foregoing Warrant and all rights evidenced thereby are hereby assigned to  whose address is.Dated:
  
  ,   Holders Signature:Holders Address:   Signature Guaranteed:  NOTE:  The signature to this Assignment Form must
correspond with the name as it appears on the face of the Warrant, without
alteration or enlargement or any change whatsoever, and must be guaranteed by a
bank or trust company.  Officers of
corporations and those acting in a fiduciary or other representative capacity
should file proper evidence of authority to assign the foregoing Warrant.