REGISTRATION RIGHTS AGREEMENT

This Registration Rights Agreement (the “Agreement”) is made and entered into as
of this 11th day of April, 2008 by and among Novelos Therapeutics, Inc., a
Delaware corporation (the “Company”), the “Investors” named in that certain
Securities Purchase Agreement, dated March 26, 2008, as amended on April 9,
2008, by and among the Company and the Investors (the “Securities Purchase
Agreement”), and the holders of the Series B Warrants (as defined below).
Capitalized terms not otherwise defined herein shall have the meanings ascribed
thereto in the Securities Purchase Agreement.
 
WHEREAS, the Company has agreed to issue and sell to the Investors, and the
Investors have agreed to purchase from the Company, 113.5 shares of Preferred
Stock and warrants (the “Series D Warrants”) to purchase up to 4,365,381 shares
of the Company’s common stock, $.00001 par value per share (the “Common Stock”),
upon the terms and conditions set forth in the Securities Purchase Agreement;
 
WHEREAS, the holders of the Series B Warrants are parties to a Registration
Rights Agreement dated May 2, 2007 (the “Prior Registration Agreement”);
 
WHEREAS, the holders of the Series B Warrants have agreed to amend the Series B
Warrants, amend the Prior Registration Statement and waive any and all
liquidated damages accruing from September 6, 2007 as a result of the Company’s
failure to register the Series B Warrants;
 
WHEREAS, the Company has agreed to register the shares of Common Stock issuable
upon conversion of the Preferred Stock and the shares of Common Stock issuable
upon exercise of the Series B Warrants and Series D Warrants in accordance with
the terms of this Agreement;
 
The parties hereby agree as follows:
 
1. Certain Definitions.
 
As used in this Agreement, the following terms shall have the following
meanings:
 
“FINRA” shall mean the Financial Industry Regulatory Authority.
 
“Holders” shall mean the Investors and the holders of the Series B Warrants and
any Affiliate or permitted transferee thereof who is a subsequent holder of any
Registrable Securities.
 
“Investors” shall mean the Investors identified in the Securities Purchase
Agreement.
 
“Preferred Stock” means the Series D Convertible Preferred Stock, par value
$0.00001 per share.
 
“Prospectus” shall mean the prospectus included in any Registration Statement,
as amended or supplemented by any prospectus supplement, with respect to the
terms of the offering of any portion of the Registrable Securities covered by
such Registration Statement and by all other amendments and supplements to the
prospectus, including post-effective amendments and all material incorporated by
reference in such prospectus.
 
“Register,” “registered” and “registration” refer to a registration made by
preparing and filing a Registration Statement or similar document in compliance
with the 1933 Act, and the declaration or ordering of effectiveness of such
Registration Statement or document.
 

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“Registrable Securities” shall mean the shares of Common Stock issuable (i) upon
the conversion of the Preferred Stock (excluding 12,000,000 shares of Common
Stock issuable upon conversion of the Preferred Stock which are registered
pursuant to the Prior Registration Statement), (ii) upon the exercise of the
Series D Warrants and (iii) upon the exercise of the Series B Warrants;
provided, that, a security shall cease to be a Registrable Security upon a sale
pursuant to a Registration Statement.
 
“Registration Statement” shall mean any registration statement of the Company
filed under the 1933 Act that covers the resale of any of the Registrable
Securities pursuant to the provisions of this Agreement, amendments and
supplements to such Registration Statement, including post-effective amendments,
and all exhibits and all material incorporated by reference in such Registration
Statement.
 
“Series B Warrants” shall mean the warrants to purchase up to 7,500,000 shares
of Common Stock dated May 2, 2007, as amended, issued pursuant to that certain
Securities Purchase Agreement dated as of April 12, 2007, as amended on May 2,
2007.
 
2. Amendment of Prior Registration Rights Agreement.
 
The holders of the Series B Warrants by their execution of this Agreement hereby
agree and acknowledge that the Prior Registration Agreement has been amended to,
among other things, remove the Series B Warrants from the definition of
Registrable Securities and as result of such amendment this Agreement supersedes
and replaces, in its entirety, the Prior Registration Agreement with respect to
the registration of the Series B Warrants and that holders of the Series B
Warrants shall have no further rights under the Prior Registration Agreement
with respect to the registration of the Series B Warrants.
 
3. Registration.
 
(a) Registration Statement. Promptly following the six month anniversary of the
Closing Date of the purchase and sale of the Preferred Stock and Series D
Warrants contemplated by the Securities Purchase Agreement, but in no event
after five (5) business days after the six month anniversary of the Closing Date
(the “Filing Deadline”), the Company shall prepare and file with the SEC one
Registration Statement on Form S-1 covering the resale of all of the Registrable
Securities without regard to any limitation on exercise of the Series D Warrants
and Series B Warrants. Such Registration Statement shall include the plan of
distribution attached hereto as Exhibit A. Such Registration Statement also
shall cover, to the extent allowable under the 1933 Act and the rules
promulgated thereunder (including Rule 416), such indeterminate number of
additional shares of Common Stock resulting from stock splits, stock dividends
or similar transactions with respect to the Registrable Securities. The
Registration Statement (and each amendment or supplement thereto, and each
request for acceleration of effectiveness thereof) shall be provided in
accordance with Section 4(c) to the Holders and their respective counsel prior
to its filing or other submission. If a Registration Statement covering the
Registrable Securities is not filed with the SEC on or prior to the Filing
Deadline, the Company will make pro rata payments to each Holder, as liquidated
damages and not as a penalty, in an amount equal to 1.5% of the aggregate amount
invested by such Holder for each 30-day period or pro rata for any portion
thereof following the date by which such Registration Statement should have been
filed for which no Registration Statement is filed with respect to the
Registrable Securities. Such payments shall be in partial compensation to the
Holders, and shall not constitute the Holders’ exclusive remedy for such events.
Such payments shall be made to each Holder in cash. The amounts payable as
liquidated damages pursuant to this paragraph shall be payable in lawful money
of the United States, and amounts payable as liquidated damages shall be paid
within two (2) Business Days of the last day of each such 30-day period during
which the Registration Statement should have been filed for which no
Registration Statement was filed with respect to the Registrable Securities.
 
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(b)  Expenses. The Company will pay all expenses associated with each
registration, including filing and printing fees, counsel and accounting fees
and expenses, costs associated with clearing the Registrable Securities for sale
under applicable state securities laws and listing fees, but excluding the fees
and disbursements of more than one law firm serving as counsel to the Holders,
and discounts, commissions, fees of underwriters, selling brokers, dealer
managers or similar securities industry professionals with respect to the
Registrable Securities being sold.
 
(c)  Effectiveness.
 
(i) The Company shall use its best efforts to have the Registration Statement
declared effective not later than the earlier to occur of (x) the 60th day
immediately following the Filing Deadline, (y) five (5) Business Days following
the Company’s receipt of a no-review letter from the SEC relating to the
Registration Statement, or (z) the 90th day following the Filing Deadline if the
Company’s receives a review from the SEC relating to the Registration Statement;
provided, however, if the Registration Statement is not declared effective
within the time period set forth above, the Company shall continue to use its
best efforts to have the Registration Statement declared effective as soon as
possible thereafter.
 
(ii) For not more than fifteen (15) consecutive days or for a total of not more
than thirty (30) days in any twelve (12) month period, the Company may delay the
disclosure of material non-public information concerning the Company, by
terminating or suspending effectiveness of any registration contemplated by this
Section 3, if the disclosure of such material non-public information at the time
is not, in the good faith opinion of the Company, in the best interests of the
Company (an “Allowed Delay”); provided, that the Company shall promptly (a)
notify the Holders in writing of the existence of (but in no event, without the
prior written consent of a Holder, shall the Company disclose to such Holder any
of the facts or circumstances regarding) material non-public information giving
rise to an Allowed Delay, and (b) advise the Holders in writing to cease all
sales under the Registration Statement until the end of the Allowed Delay.
 
(d)  Underwritten Offering. If any offering pursuant to a Registration Statement
filed pursuant to Section 3(a) hereof involves an underwritten offering, the
Company shall have the right to select an investment banker and manager to
administer the offering, subject to the reasonable satisfaction of the Requisite
Holders.
 
4. Company Obligations. The Company will use its best efforts to effect the
registration of the Registrable Securities in accordance with the terms hereof,
and pursuant thereto the Company will, as expeditiously as possible:
 
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(a)  use its best efforts to cause such Registration Statement to become
effective and to remain continuously effective for a period that will terminate
upon the earlier of (i) the date on which all Registrable Securities covered by
such Registration Statement, as amended from time to time, have been sold and
(ii) two years from the Closing Date;
 
(b)  prepare and file with the SEC such amendments and post-effective amendments
to the Registration Statement and the Prospectus as may be necessary to keep the
Registration Statement effective for the period specified in Section 4(a) and to
comply with the provisions of the 1933 Act and the 1934 Act with respect to the
distribution of all Registrable Securities;
 
(c)  provide copies to and permit counsel to the Investors to review each
Registration Statement and all amendments thereto no fewer than three (3) days
prior to their filing with the SEC and not file any document to which such
counsel reasonably objects within three (3) days following receipt by such
counsel of such Registration Statement and/or amendments thereto;
 
(d)  furnish to the Holders and their legal counsel (i) promptly after the same
is prepared and publicly distributed, filed with the SEC, or received by the
Company (but not later than two (2) Business Days after the filing date, receipt
date or sending date, as the case may be), an electronic copy of any
Registration Statement and any amendment thereto, each preliminary prospectus
and Prospectus and each amendment or supplement thereto, and each letter written
by or on behalf of the Company to the SEC or the staff of the SEC, and each item
of correspondence from the SEC or the staff of the SEC, in each case relating to
such Registration Statement (other than any portion thereof which contains
information for which the Company has sought confidential treatment), and (ii)
such number of copies of a Prospectus, including a preliminary prospectus, and
all amendments and supplements thereto and such other documents as each Holder
may reasonably request in order to facilitate the disposition of the Registrable
Securities owned by such Holder, which in any event, shall not exceed ten (10)
Prospectuses;
 
(e)  in the event the Company selects an underwriter for the offering, the
Company shall enter into and perform its reasonable obligations under an
underwriting agreement, in usual and customary form, including, without
limitation, customary indemnification and contribution obligations, with the
underwriter of such offering;
 
(f)  if required by the underwriter, the Company shall furnish, on the effective
date of the Registration Statement (i) an opinion, dated as of such date, from
independent legal counsel representing the Company for purposes of such
Registration Statement, in form, scope and substance as is customarily given in
an underwritten public offering, addressed to the underwriter and (ii) a letter,
dated such date, from the Company’s independent certified public accountants in
form and substance as is customarily given by independent certified public
accountants to underwriters in an underwritten public offering, addressed to the
underwriter and the Holders;
 
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(g)  use its reasonable best efforts to prevent the issuance of any stop order
or other suspension of effectiveness and, if such order is issued, obtain the
withdrawal of any such order at the earliest possible moment;
 
(h)  prior to any public offering of Registrable Securities, use its reasonable
best efforts to register or qualify or cooperate with the Holders and their
counsel in connection with the registration or qualification of such Registrable
Securities for offer and sale under the securities or blue sky laws of such
jurisdictions reasonably requested by the Holders and do any and all other
reasonable acts or things necessary or advisable to enable the distribution in
such jurisdictions of the Registrable Securities covered by the Registration
Statement;
 
(i)  cause all Registrable Securities covered by a Registration Statement to be
listed or traded on each securities exchange, interdealer quotation system or
other market on which similar securities issued by the Company are then listed
or traded;
 
(j)  immediately notify the Holders, at any time when a Prospectus relating to
the Registrable Securities is required to be delivered under the 1933 Act, upon
discovery that, or upon the happening of any event as a result of which, the
Prospectus included in such Registration Statement, as then in effect, includes
an untrue statement of a material fact or omits to state any material fact
required to be stated therein or necessary to make the statements therein not
misleading in light of the circumstances then existing, and at the request of
any such Holder, promptly prepare and furnish to such Holder a reasonable number
of copies of a supplement to or an amendment of such Prospectus as may be
necessary so that, as thereafter delivered to the purchasers of such Registrable
Securities, such Prospectus shall not include an untrue statement of a material
fact or omit to state a material fact required to be stated therein or necessary
to make the statements therein not misleading in light of the circumstances then
existing; and
 
(k)  otherwise use its best efforts to comply with all applicable rules and
regulations of the SEC under the 1933 Act and the 1934 Act and take such other
actions as may be reasonably necessary to facilitate the registration of the
Registrable Securities hereunder; and make available to its security holders, as
soon as reasonably practicable, but not later than the Availability Date (as
defined below), an earnings statement covering a period of at least twelve (12)
months, beginning after the effective date of each Registration Statement, which
earnings statement shall satisfy the provisions of Section 11(a) of the 1933 Act
(for the purpose of this subsection 3(k), “Availability Date” means the 45th day
following the end of the fourth fiscal quarter that includes the effective date
of such Registration Statement, except that, if such fourth fiscal quarter is
the last quarter of the Company’s fiscal year, “Availability Date” means the
90th day after the end of such fourth fiscal quarter).
 
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5. Due Diligence Review; Information. Upon receipt of an appropriate
confidentiality agreement, the Company shall make available, during normal
business hours, for inspection and review by the Holders, advisors to and
representatives of the Holders (who may or may not be affiliated with the
Holders), and any underwriter participating in any disposition of Common Stock
on behalf of the Holders pursuant to a Registration Statement or amendments or
supplements thereto or any blue sky, FINRA or other filing, all financial and
other records, all filings with the SEC, and all other corporate documents and
properties of the Company as may be reasonably necessary for the purpose of such
review, and cause the Company’s officers, directors and employees, within a
reasonable time period, to supply all such information reasonably requested by
the Holders or any such representative, advisor or underwriter in connection
with such Registration Statement (including, without limitation, in response to
all questions and other inquiries reasonably made or submitted by any of them),
prior to and from time to time after the filing and effectiveness of the
Registration Statement for the sole purpose of enabling the Holders and such
representatives, advisors and underwriters and their respective accountants and
attorneys to conduct initial and ongoing due diligence with respect to the
Company and the accuracy of such Registration Statement.

Notwithstanding the foregoing, the Company shall not disclose material nonpublic
information to the Holders, or to advisors to or representatives of the Holders,
unless prior to disclosure of such information the Company identifies such
information as being material nonpublic information and provides the Holders,
such advisors and representatives with the opportunity to accept or refuse to
accept such material nonpublic information for review.
 
6. Obligations of the Holders.
 
(a)  Each Holder agrees to furnish to the Company a completed Questionnaire in
the form attached to this Agreement as Exhibit B (a “Selling Shareholder
Questionnaire”) not prior to 120 days after the Closing Date and not more than
150 days after the Closing Date. A Holder who fails to furnish a Selling
Stockholder Questionnaire within 150 days after the Closing Date may have its
Registrable Securities excluded from the Registration Statement, provided that
the Company has provided such Holder with notice at least 20 days prior (but no
more than 60 days prior) to the expiration of such 150 day period.
 
(b)  Each Holder, by its acceptance of the Registrable Securities, agrees to
cooperate with the Company as reasonably requested by the Company in connection
with the preparation and filing of a Registration Statement hereunder, unless
such Holder has notified the Company in writing of its election to exclude all
of its Registrable Securities from such Registration Statement.
 
(c)  In the event the Company, at the request of the Holders, determines to
engage the services of an underwriter, each such Holder agrees to enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, including, without limitation, customary indemnification and contribution
obligations, with the managing underwriter of such offering and take such other
actions as are reasonably required in order to expedite or facilitate the
dispositions of the Registrable Securities.
 
(d)  Each Holder agrees that, upon receipt of any notice from the Company of the
happening of any event rendering a Registration Statement no longer effective,
such Holder will immediately discontinue disposition of Registrable Securities
pursuant to the Registration Statement covering such Registrable Securities,
until the Holder’s receipt of copies of the supplemented or amended Prospectus
filed with the SEC and declared effective and, if so directed by the Company,
the Holder shall deliver to the Company (at the expense of the Company) or
destroy (and deliver to the Company a certificate of destruction) all copies in
the Holder’s possession of the Prospectus covering the Registrable Securities
current at the time of receipt of such notice.
 
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(e)  No Holder may participate in any third party underwritten registration
hereunder unless it (i) agrees to sell the Registrable Securities on the basis
provided in any underwriting arrangements in usual and customary form entered
into by the Company, (ii) completes and executes all questionnaires, powers of
attorney, indemnities, underwriting agreements and other documents reasonably
required under the terms of such underwriting arrangements, and (iii) agrees to
pay its pro rata share of all underwriting discounts and commissions.
Notwithstanding the foregoing, no Holder shall be required to make any
representations to such underwriter, other than those with respect to itself and
the Registrable Securities owned by it, including its right to sell the
Registrable Securities, and any indemnification in favor of the underwriter by
the Holders shall be several and not joint and limited in the case of any
Holder, to the net proceeds received by such Holder from the sale of its
Registrable Securities. The scope of any such indemnification in favor of an
underwriter shall be limited to the same extent as the indemnity provided in
Section 7(b) hereof.
 
7. Indemnification.
 
(a)  Indemnification by the Company. The Company will indemnify and hold
harmless each Holder and any controlling person (as defined in Section 15 of the
1933 Act) and their respective officers, directors, members, employees and
agents, successors and assigns (the “Indemnified Persons”), against any losses,
claims, damages or liabilities, joint or several, to which such Indemnified
Person may become subject under the 1933 Act or otherwise, insofar as such
losses, claims, damages or liabilities (or actions in respect thereof) arise out
of or are based upon: (i) any untrue statement or alleged untrue statement of
any material fact contained in any Registration Statement, any preliminary
prospectus or final prospectus contained therein, or any amendment or supplement
thereof; (ii) any blue sky application or other document executed by the Company
specifically for blue sky compliance or based upon written information furnished
by the Company filed in any state or other jurisdiction in order to qualify any
or all of the Registrable Securities under the securities laws thereof (any such
application, document or information herein called a “Blue Sky Application”);
(iii) the omission or alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading;
(iv) any violation by the Company, or its directors, officers, employees or
agents of any rule or regulation promulgated under the 1933 Act applicable to
the Company or its directors, officers, employees or agents and relating to
action or inaction required of the Company or any of them in connection with
such registration; or (v) any failure to register or qualify the Registrable
Securities included in any such Registration Statement in any state where the
Company or its agents has affirmatively undertaken or agreed in writing that the
Company will undertake such registration or qualification on a Holder’s behalf
(the undertaking of any underwriter chosen by the Company being attributed to
the Company) and will reimburse such Holder, and each such officer, director or
member and each such controlling person for any legal or other expenses
reasonably incurred by them in connection with investigating or defending any
such loss, claim, damage, liability or action; provided, however, that the
Company will not be liable in any such case if and to the extent that any such
loss, claim, damage or liability arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission made in
conformity with information furnished in writing by such Holder or any such
controlling person specifically for use in such Registration Statement or
Prospectus.
 
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(b)  Indemnification by the Holders. In connection with any Registration
Statement pursuant to the terms of this Agreement, each Holder will furnish to
the Company in writing such information as the Company reasonably requests
concerning such Holder or the proposed manner of such Holder’s distribution for
use in connection with any Registration Statement or Prospectus and agrees,
severally but not jointly, to indemnify and hold harmless, to the fullest extent
permitted by law, the Company, its Subsidiaries and its and their respective
directors, officers, employees, shareholders and each person who controls the
Company (within the meaning of the 1933 Act) against any losses, claims,
damages, liabilities and expenses (including reasonable attorney fees) resulting
from any untrue statement of a material fact or any omission of a material fact
required to be stated in the Registration Statement or Prospectus or preliminary
prospectus or amendment or supplement thereto or necessary to make the
statements therein not misleading, to the extent, but only to the extent that
such untrue statement or omission is contained in any information furnished in
writing by such Holder to the Company specifically for inclusion in such
Registration Statement or Prospectus or amendment or supplement thereto. In no
event shall the liability of a Holder be greater in amount than the aggregate
dollar amount of the proceeds (net of all expenses paid by such Holder and the
amount of any damages such Holder has otherwise been required to pay by reason
of such untrue statement or omission) received by such Holder upon the sale of
the Registrable Securities included in the Registration Statement giving rise to
such indemnification obligation.
 
(c)  Conduct of Indemnification Proceedings. Any person entitled to
indemnification hereunder shall (i) give prompt notice to the indemnifying party
of any claim with respect to which it seeks indemnification and (ii) permit such
indemnifying party to assume the defense of such claim with counsel reasonably
satisfactory to the indemnified party; provided that any person entitled to
indemnification hereunder shall have the right to employ separate counsel and to
participate in the defense of such claim, but the fees and expenses of such
counsel shall be at the expense of such person unless (a) the indemnifying party
has agreed to pay such fees or expenses, or (b) the indemnifying party shall
have failed to assume the defense of such claim and employ counsel reasonably
satisfactory to such person or (c) in the reasonable judgment of any such
person, based upon advice of its counsel, a conflict of interest exists between
such person and the indemnifying party with respect to such claims (in which
case, if the person notifies the indemnifying party in writing that such person
elects to employ separate counsel at the expense of the indemnifying party, the
indemnifying party shall not have the right to assume the defense of such claim
on behalf of such person); and provided, further, that the failure of any
indemnified party to give notice as provided herein shall not relieve the
indemnifying party of its obligations hereunder, except to the extent that such
failure to give notice shall materially adversely affect the indemnifying party
in the defense of any such claim or litigation. It is understood that the
indemnifying party shall not, in connection with any proceeding in the same
jurisdiction, be liable for fees or expenses of more than one separate firm of
attorneys at any time for all such indemnified parties. No indemnifying party
will, except with the consent of the indemnified party, consent to entry of any
judgment or enter into any settlement that does not include as an unconditional
term thereof the giving by the claimant or plaintiff to such indemnified party
of a release from all liability in respect of such claim or litigation.
 
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(d)  Contribution. If for any reason the indemnification provided for in the
preceding paragraphs (a) and (b) is unavailable to an indemnified party or
insufficient to hold it completely harmless, other than as expressly specified
therein, then the indemnifying party shall contribute to the amount paid or
payable by the indemnified party as a result of such loss, claim, damage or
liability in such proportion as is appropriate to reflect the relative fault of
the indemnified party and the indemnifying party, as well as any other relevant
equitable considerations. No person guilty of fraudulent misrepresentation
within the meaning of Section 11(f) of the 1933 Act shall be entitled to
contribution from any person not guilty of such fraudulent misrepresentation. In
no event shall the contribution obligation of a Holder be greater in amount than
the aggregate dollar amount of the proceeds (net of all expenses paid by such
holder and the amount of any damages such Holder has otherwise been required to
pay by reason of such untrue or alleged untrue statement or omission or alleged
omission) received by it upon the sale of the Registrable Securities giving rise
to such contribution obligation.
 
8. Miscellaneous.
 
(a)  Amendments and Waivers. This Agreement shall not be amended except by a
writing signed by (i) the Company and (ii) the Requisite Holders. The Company
may take any action herein prohibited, or omit to perform any act herein
required to be performed by it, only if the Company shall have obtained the
written consent to such amendment, action or omission to act, of the Requisite
Holders.
 
(b)  Notices. All notices and other communications provided for or permitted
hereunder shall be made as set forth in Section 11.4 of the Securities Purchase
Agreement.
 
(c)  Assignments and Transfers by Holders. The provisions of this Agreement
shall be binding upon and inure to the benefit of the Holders and their
respective successors and assigns. A Holder may transfer or assign, in whole or
from time to time in part, to one or more persons its rights hereunder in
connection with the transfer of Registrable Securities by such Holder to such
person, provided, that, such Holder complies with all applicable laws thereto
and provides written notice of assignment to the Company promptly after such
assignment is effected.
 
(d)  Assignments and Transfers by the Company. This Agreement shall not be
assigned by the Company without the prior written consent of each Holder, except
that without the prior written consent of the Holders, but after notice duly
given, the Company shall assign its rights and delegate its duties hereunder to
any successor-in-interest corporation, and such successor-in-interest shall
assume such rights and duties, in the event of a merger or consolidation of the
Company with or into another corporation or the sale of all or substantially all
of the Company’s assets.
 
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(e)  Benefits of the Agreement. The terms and conditions of this Agreement shall
inure to the benefit of and be binding upon the respective permitted successors
and assigns of the parties. Nothing in this Agreement, express or implied, is
intended to confer upon any party other than the parties hereto or their
respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.
 
(f)  Counterparts; Faxes. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. This Agreement may also
be executed via facsimile, which shall be deemed an original.
 
(g)  Titles and Subtitles. The titles and subtitles used in this Agreement are
used for convenience only and are not to be considered in construing or
interpreting this Agreement.
 
(h)  Severability. Any provision of this Agreement that is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the
remaining provisions hereof but shall be interpreted as if it were written so as
to be enforceable to the maximum extent permitted by applicable law, and any
such prohibition or unenforceability in any jurisdiction shall not invalidate or
render unenforceable such provision in any other jurisdiction. To the extent
permitted by applicable law, the parties hereby waive any provision of law which
renders any provisions hereof prohibited or unenforceable in any respect.
 
(i)  Further Assurances. The parties shall execute and deliver all such further
instruments and documents and take all such other actions as may reasonably be
required to carry out the transactions contemplated hereby and to evidence the
fulfillment of the agreements herein contained.
 
(j)  Entire Agreement. This Agreement is intended by the parties as a final
expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto in respect of
the subject matter contained herein. This Agreement supersedes all prior
agreements and understandings between the parties with respect to such subject
matter.
 
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(k)  Governing Law; Consent to Jurisdiction. This Agreement shall be governed
by, and construed in accordance with, the internal laws of the State of New York
without regard to the choice of law principles thereof. Each of the parties
hereto irrevocably submits to the exclusive jurisdiction of the courts of the
State of New York located in New York County and the United States District
Court for the Southern District of New York for the purpose of any suit, action,
proceeding or judgment relating to or arising out of this Agreement and the
transactions contemplated hereby. Service of process in connection with any such
suit, action or proceeding may be served on each party hereto anywhere in the
world by the same methods as are specified for the giving of notices under this
Agreement. Each of the parties hereto irrevocably consents to the jurisdiction
of any such court in any such suit, action or proceeding and to the laying of
venue in such court. Each party hereto irrevocably waives any objection to the
laying of venue of any such suit, action or proceeding brought in such courts
and irrevocably waives any claim that any such suit, action or proceeding
brought in any such court has been brought in an inconvenient forum. THE COMPANY
AND EACH OF THE HOLDERS HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY
JURY IN ANY LEGAL PROCEEDING RELATING TO OR ARISING OUT OF THIS AGREEMENT AND
THE TRANSACTIONS CONTEMPLATED HEREBY.
 
[Signature Pages Follow]
 
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Company Signature Page to Registration Rights Agreement
 
IN WITNESS WHEREOF, the Company has executed this Agreement or caused its duly
authorized officer to execute this Agreement as of the date first above written.
 

 
NOVELOS THERAPEUTICS, INC.
     
By:
 /s/ Harry. S. Palmin
 
Name: Harry S. Palmin
 
Title:   President and CEO

 
-12-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Xmark Opportunity Fund, Ltd.
 
Name of entity
 
By:
Xmark Opportunity Manager, LLC,
 
its Investment Manager
 
By:
Xmark Opportunity Partners, LLC,
 
its Sole Member
 
By:
Xmark Capital Partners, LLC,
 
its Managing Member
 
By:
/s/ Mitchell D. Kaye
 
Name: Mitchell D. Kaye
Title: Chief Executive Officer
 
Cayman Islands
 
Jurisdiction of organization of entity
 
Address:
 
90 Grove Street
Ridgefield, CT 06877

 
-13-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Xmark Opportunity Fund, L.P.
 
Name of entity
 
By:
Xmark Opportunity GP, LLC
 
its General Partner
 
By:
Xmark Opportunity Partners, LLC,
 
its Sole Member
 
By:
Xmark Capital Partners, LLC,
 
its Managing Member
 
By:
/s/ Mitchell D. Kaye
 
Name: Mitchell D. Kaye
Title: Chief Executive Officer
 
Delaware
 
Jurisdiction of organization of entity
 
Address:
 
90 Grove Street
Ridgefield, CT 06877

 
-14-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Xmark JV Investment Partners, LLC
 
Name of entity
 
By:
Xmark Opportunity Partners, LLC
 
its Investment Manager
 
By:
 Xmark Capital Partners, LLC,
 
its Managing Member
 
By:
/s/ Mitchell D. Kaye
 
Name: Mitchell D. Kaye
Title: Chief Executive Officer
 
Delaware
 
Jurisdiction of organization of entity
 
Address:
 
90 Grove Street
Ridgefield, CT 06877

 
-15-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Caduceus Capital Master Fund Limited
 
Name of entity
 
By:
/s/ Samuel D. Isaly
 
Name: Samuel D. Isaly
Title: Managing Partner, OrbiMed Advisors LLC
 
Print jurisdiction of organization of entity: Bermuda
 
Address:
c/o OrbiMed Advisors LLC
767 Third Avenue, 30th Floor
New York, NY 10017

 
-16-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement of the date first above written.

Caduceus Capital II, L.P.
 
Name of entity
 
By:
/s/ Samuel D. Isaly
 
Name: Samuel D. Isaly
Title: Managing Partner, OrbiMed Advisors LLC
 
Print jurisdiction of organization of entity: Delaware
 
Address:
c/o OrbiMed Advisors LLC
767 Third Avenue, 30th Floor
New York, NY 10017

 
-17-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Summer Street Life Sciences Hedge Fund Investors LLC
 
Name of entity
 
By:
/s/ Samuel D. Isaly
 
Name: Samuel D. Isaly
Title: Managing Partner, OrbiMed Advisors LLC
 
Print jurisdiction of organization of entity: Delaware
 
Address:
c/o OrbiMed Advisors LLC
767 Third Avenue, 30th Floor
New York, NY 10017

 
-18-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written

UBS Eucalyptus Fund, L.L.C.
 
Name of entity
 
By:
/s/ Samuel D. Isaly
 
Name: Samuel D. Isaly
Title: Managing Partner, OrbiMed Advisors LLC
 
Print jurisdiction of organization of entity: Delaware
 
Address:
c/o OrbiMed Advisors LLC
767 Third Avenue, 30th Floor
New York, NY 10017

 
-19-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

PW Eucalyptus Fund, Ltd.
 
Name of entity
 
By:
/s/ Samuel D. Isaly
 
Name: Samuel D. Isaly
Title: Managing Partner, OrbiMed Advisors LLC
 
Print jurisdiction of organization of entity: Cayman Islands
 
Address:
c/o OrbiMed Advisors LLC
767 Third Avenue, 30th Floor
New York, NY 10017

 
-20-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Knoll Capital Fund II Master Fund Ltd.
 
Name of entity
 
By:
/s/ Fred Knoll
 
Name:   Fred Knoll
Title:     KOM Capital Management
              Investment Manager
 
Print jurisdiction of organization of entity:
 
Address:
c/o KOM Capital Management
666 Fifth Avenue, Suite 3702,
New York, NY 10103

 
-21-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Europa International, Inc.
 
Name of entity
 
By:
/s/ Fred Knoll
 
Name:   Fred Knoll
Title:     Knoll Capital Management
              Investment Manager for
              Europa International, Inc.
 
Print jurisdiction of organization of entity
 
Address:
c/o Knoll Capital Management
666 Fifth Avenue, Suite 3702,
New York, NY 10103

 
-22-

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Holder Signature Page to Registration Rights Agreement

IN WITNESS WHEREOF, the undersigned has executed this Registration Rights
Agreement or caused its duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

Hunt BioVenures, L.P.
 
Name of entity
 
By: HBV GP, L.L.C., its General Partner
 
By:
/s/ J. Fulton Murray, III
   
Name: J. Fulton Murray, III, Manager
 
Jurisdiction of organization of entity: Delaware
 
Address:
Hunt Investments
1900 N. Akard
Dallas, TX 75201
Attn: Michael T. Bierman, J. Fulton Murray, III and Benjamin D. Nelson

 
-23-

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Exhibit A

Plan of Distribution

The selling stockholders, which as used herein includes donees, pledgees,
transferees or other successors-in-interest selling shares of common stock or
interests in shares of common stock received after the date of this prospectus
from a selling stockholder as a gift, pledge, partnership distribution or other
transfer, may, from time to time, sell, transfer or otherwise dispose of any or
all of their shares of common stock or interests in shares of common stock on
any stock exchange, market or trading facility on which the shares are traded or
in private transactions. These dispositions may be at fixed prices, at
prevailing market prices at the time of sale, at prices related to the
prevailing market price, at varying prices determined at the time of sale, or at
negotiated prices.

The selling stockholders may use any one or more of the following methods when
disposing of shares or interests therein:

- ordinary brokerage transactions and transactions in which the broker-dealer
solicits purchasers;

- block trades in which the broker-dealer will attempt to sell the shares as
agent, but may position and resell a portion of the block as principal to
facilitate the transaction;

- purchases by a broker-dealer as principal and resale by the broker-dealer for
its account;

- an exchange distribution in accordance with the rules of the applicable
exchange;

- privately negotiated transactions;

- short sales;

- through the writing or settlement of options or other hedging transactions,
whether through an options exchange or otherwise;

- broker-dealers may agree with the selling stockholders to sell a specified
number of such shares at a stipulated price per share;

- a combination of any such methods of sale; and

- any other method permitted pursuant to applicable law.

The selling stockholders may, from time to time, pledge or grant a security
interest in some or all of the shares of common stock owned by them and, if they
default in the performance of their secured obligations, the pledgees or secured
parties may offer and sell the shares of common stock, from time to time, under
this prospectus, or under an amendment to this prospectus under Rule 424(b)(3)
or other applicable provision of the Securities Act amending the list of selling
stockholders to include the pledgee, transferee or other successors in interest
as selling stockholders under this prospectus. The selling stockholders also may
transfer the shares of common stock in other circumstances, in which case the
transferees, pledgees or other successors in interest will be the selling
beneficial owners for purposes of this prospectus.

-24-

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In connection with the sale of our common stock or interests therein, the
selling stockholders may enter into hedging transactions with broker-dealers or
other financial institutions, which may in turn engage in short sales of the
common stock in the course of hedging the positions they assume. The selling
stockholders may also sell shares of our common stock short and deliver these
securities to close out their short positions, or loan or pledge the common
stock to broker-dealers that in turn may sell these securities. The selling
stockholders may also enter into option or other transactions with
broker-dealers or other financial institutions or the creation of one or more
derivative securities which require the delivery to such broker-dealer or other
financial institution of shares offered by this prospectus, which shares such
broker-dealer or other financial institution may resell pursuant to this
prospectus (as supplemented or amended to reflect such transaction).

The aggregate proceeds to the selling stockholders from the sale of the common
stock offered by them will be the purchase price of the common stock less
discounts or commissions, if any. Each of the selling stockholders reserves the
right to accept and, together with their agents from time to time, to reject, in
whole or in part, any proposed purchase of common stock to be made directly or
through agents. We will not receive any of the proceeds from this offering. Upon
any exercise of the warrants by payment of cash, however, we will receive the
exercise price of the warrants.

The selling stockholders also may resell all or a portion of the shares in open
market transactions in reliance upon Rule 144 under the Securities Act of 1933,
provided that they meet the criteria and conform to the requirements of that
rule.

The selling stockholders and any underwriters, broker-dealers or agents that
participate in the sale of the common stock or interests therein may be
"underwriters" within the meaning of Section 2(11) of the Securities Act. Any
discounts, commissions, concessions or profit they earn on any resale of the
shares may be underwriting discounts and commissions under the Securities Act.
Selling stockholders who are "underwriters" within the meaning of Section 2(11)
of the Securities Act will be subject to the prospectus delivery requirements of
the Securities Act.

To the extent required, the shares of our common stock to be sold, the names of
the selling stockholders, the respective purchase prices and public offering
prices, the names of any agents, dealer or underwriter, any applicable
commissions or discounts with respect to a particular offer will be set forth in
an accompanying prospectus supplement or, if appropriate, a post-effective
amendment to the registration statement that includes this prospectus.

In order to comply with the securities laws of some states, if applicable, the
common stock may be sold in these jurisdictions only through registered or
licensed brokers or dealers. In addition, in some states the common stock may
not be sold unless it has been registered or qualified for sale or an exemption
from registration or qualification requirements is available and is complied
with.

-25-

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We have advised the selling stockholders that the anti-manipulation rules of
Regulation M under the Exchange Act may apply to sales of shares in the market
and to the activities of the selling stockholders and their affiliates. In
addition, we will make copies of this prospectus (as it may be supplemented or
amended from time to time) available to the selling stockholders for the purpose
of satisfying the prospectus delivery requirements of the Securities Act. The
selling stockholders may indemnify any broker-dealer that participates in
transactions involving the sale of the shares against certain liabilities,
including liabilities arising under the Securities Act.

We have agreed to indemnify the selling stockholders against liabilities,
including liabilities under the Securities Act and state securities laws,
relating to the registration of the shares offered by this prospectus.

We have agreed with the selling stockholders to keep the registration statement
of which this prospectus constitutes a part effective until the earlier of (1)
such time as all of the shares covered by this prospectus have been disposed of
pursuant to and in accordance with the registration statement or (2) two years
from the Closing Date.
 
-26-

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Exhibit B

Selling Stockholder Questionnaire

To:
Novelos Therapeutics, Inc.
 
c/o Foley Hoag LLP
 
155 Seaport Boulevard
 
Boston, MA 02210
 
Attention: Amanda Kirouac, Esq.
 
Facsimile: (617) 832-1000

 
Reference is made to the Registration Rights Agreement (the “Agreement”), made
between Novelos Therapeutics, Inc., a Delaware corporation (the “Company”), and
the Holders noted therein.
 
Pursuant to Section 6(a) of the Agreement, the undersigned hereby furnishes to
the Company the following information for use by the Company in connection with
the preparation of the Registration Statement.
 

(1)
Name and Contact Information:

 
Full legal name of record holder:
 
Address of record holder:
     
Social Security Number or Taxpayer
identification number of record holder:
 
Identity of beneficial owner (if
different than record holder):
 
Name of contact person:
 
Telephone number of contact person:
 
Fax number of contact person:
 
E-mail address of contact person:
 

 
-27-

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(2)
Beneficial Ownership of Registrable Securities:

 

 
(a)
Number of Registrable Securities owned by Selling Stockholder:

 

 
(b)
Number of Registrable Securities requested to be registered:

 

 
(3)
Beneficial Ownership of Other Securities of the Company Owned by the Selling
Stockholder:

 
Except as set forth below in this Item (3), the undersigned is not the
beneficial or registered owner of any securities of the Company other than the
Registrable Securities listed above in Item (2)(a).
 
Type and amount of other securities beneficially owned by the Selling
Stockholder:
 

(4)
Relationships with the Company:

 
Except as set forth below, neither the undersigned nor any of its affiliates,
officers, directors or principal equity holders (5% or more) has held any
position or office or has had any other material relationship with the Company
(or its predecessors or affiliates) during the past three years.
 
State any exceptions here:
 

(5)
Plan of Distribution:

 
Except as set forth below, the undersigned intends to distribute pursuant to the
Registration Statement the Registrable Securities listed above in Item (2) in
accordance with the “Plan of Distribution” section set forth therein:
 
State any exceptions here:
 
-28-

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(6)
Selling Stockholder Affiliations:

 
(a) Is the Selling Stockholder a registered broker-dealer?
 
(b) Is the Selling Stockholder an affiliate of a registered broker-dealer(s)?
(For purposes of this response, an “affiliate” of, or person “affiliated” with,
a specified person, is a person that directly, or indirectly through one or more
intermediaries, controls or is controlled by, or is under common control with,
the person specified.)
 
(c) If the answer to Item (6)(b) is yes, identify the registered
broker-dealer(s) and describe the nature of the affiliation(s):
 
(d) If the answer to Item (6)(b) is yes, did the Selling Stockholder acquire the
Registrable Securities in the ordinary course of business (if not, please
explain)?
 
(e) If the answer to Item (6)(b) is yes, did the Selling Stockholder, at the
time of purchase of the Registrable Securities, have any agreements, plans or
understandings, directly or indirectly, with any person to distribute the
Registrable Securities (if yes, please explain)?
 

(7)
Voting or Investment Control over the Registrable Securities:

 
If the Selling Stockholder is not a natural person, please identify the natural
person or persons who have voting or investment control over the Registrable
Securities listed in Item (2) above:
 
-29-

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Pursuant to Section 3(c) of the Agreement, the undersigned acknowledges that the
Company may, by notice to the Holder at its last known address, suspend or
withdraw the Registration Statement and require that the undersigned immediately
cease sales of Registrable Securities pursuant to the Registration Statement
under certain circumstances described in the Agreement. At any time that such
notice has been given, the undersigned may not sell Registrable Securities
pursuant to the Registration Statement.
 
The undersigned hereby agrees to sell such shares only pursuant to and in the
manner contemplated by the Registration Statement, including the Plan of
Distribution section contained therein (in substantially the form attached
hereto as Exhibit A), or pursuant to an exemption from the registration
requirements under the Securities Act. The undersigned hereby further
acknowledges that pursuant to Section 7(b) of the Agreement, the undersigned
shall indemnify the Company and each of its directors and officers against, and
hold the Company and each of its directors and officers harmless from, any
losses, claims, damages, expenses or liabilities (including reasonable attorneys
fees) to which the Company or its directors and officers may become subject by
reason of any statement or omission in the Registration Statement made in
reliance upon, or in conformity with, a written statement by the undersigned,
including the information furnished in this Questionnaire by the undersigned.
 
By signing below, the undersigned consents to the disclosure of the information
contained herein in its answers to Items (1) through (7) above and the inclusion
of such information in the Registration Statement, any amendments thereto and
the related prospectus. The undersigned understands that such information will
be relied upon by the Company in connection with the preparation or amendment of
the Registration Statement and the related prospectus.
 
The undersigned has reviewed the answers to the above questions and affirms that
the same are true, complete and accurate. THE UNDERSIGNED AGREES TO NOTIFY THE
COMPANY IMMEDIATELY OF ANY MATERIAL CHANGES IN THE FOREGOING INFORMATION.

Dated:
 
, 2008
 
       

Signature of Record Holder
(Please sign your name in exactly the same manner as the certificate(s) for the
shares being registered)
 
-30-

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