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                                                                    EXHIBIT 10.1



                          REGISTRATION RIGHTS AGREEMENT

            This Registration Rights Agreement (this "Agreement") is made and
entered into as of January 29, 2004, by and between CytRx Corporation, a
Delaware corporation (the "Company"), and Advanced BioScience Laboratories,
Inc., a Delaware corporation ("ABL").

            WHEREAS, pursuant to the Collaboration Agreement, dated as of
December 22, 2003, by and among the Company, ABL, and the University of
Massachusetts (the "Collaboration Agreement"), the Company has agreed to issue
shares of its common stock to ABL upon the occurrence of the event set forth in
Section 11(iv) thereof (the "Filing Event"); and

            WHEREAS, to induce ABL to execute and deliver the Collaboration
Agreement, the Company has agreed to provide certain registration rights under
the Securities Act of 1933, as amended, with respect to the Common Shares (as
defined below).

            NOW, THEREFORE, in consideration of the representations, warranties
and agreements contained herein and other good and valuable consideration, the
receipt and legal adequacy of which are hereby acknowledged by the parties, the
Company and ABL hereby agree as follows:

      1.    Definitions.

            Capitalized terms used but not otherwise defined herein shall have
the meanings given such terms in the Collaboration Agreement. As used in this
Agreement, the following terms shall have the following meanings:

            "Affiliate" means, with respect to any Person, any other Person that
directly or indirectly controls or is controlled by or under common control with
such Person. For the purposes of this definition, "control," when used with
respect to any Person, means the possession, direct or indirect, of the power to
direct or cause the direction of the management and policies of such Person,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "affiliated," "controlling" and "controlled" have meanings
correlative to the foregoing.

            "Blackout Period" shall have the meaning set forth in Section 3(m).

            "Board" shall have the meaning set forth in Section 3(m).

            "Business Day" means any day except Saturday, Sunday and any day
which is a legal holiday or a day on which banking institutions in the state of
California generally are authorized or required by law or other government
actions to close.

            "Commission" means the Securities and Exchange Commission.

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            "Common Shares" shall have the meaning set forth in the definition
of "Registrable Securities."

            "Common Stock" means the Company's Common Stock, $.001 par value.

            "Effectiveness Date" means with respect to the Registration
Statement the earlier of (i) the 180th day following the Filing Event, before
which the Company will use its commercially reasonable best efforts to cause the
Registration Statement to become effective, and (ii) the date which is within
five (5) Business Days after the date on which the Commission informs the
Company in writing (a) that the Commission will not review the Registration
Statement, or (b) that the Company may request the acceleration of the
effectiveness of the Registration Statement.

            "Effectiveness Period" shall have the meaning set forth in Section
2.

            "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

            "Holder" means, collectively, each holder from time to time of
Registrable Securities including, without limitation, ABL and its assignees. To
the extent this Agreement refers to an election, consent, waiver, request or
approval of or by the Holder, such reference shall mean an election, consent,
waiver, request or approval by the holders of a majority in interest of the
then-outstanding Registrable Securities (on an as exercised basis).

            "Indemnified Party" shall have the meaning set forth in Section
6(c).

            "Indemnifying Party" shall have the meaning set forth in Section
6(c).

            "Losses" shall have the meaning set forth in Section 6(a).

            "NASDAQ" shall mean the NASDAQ Stock Market.

            "Person" means an individual or a corporation, partnership, trust,
incorporated or unincorporated association, joint venture, limited liability
company, joint stock company, government (or an agency or political subdivision
thereof) or other entity of any kind.

            "Proceeding" means an action, claim, suit, investigation or
proceeding (including, without limitation, an investigation or partial
proceeding, such as a deposition), whether commenced or threatened.

            "Prospectus" means the prospectus included in the Registration
Statement (including, without limitation, a prospectus that includes any
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A promulgated under the
Securities Act), 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 the Registration Statement, and all other amendments and
supplements to the Prospectus, including post-effective amendments, and all
material incorporated by reference in such Prospectus.

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            "Registrable Securities" means the shares of Common Stock issued or
issuable pursuant to the Collaboration Agreement, and upon any stock split,
stock dividend, recapitalization or similar event with respect to such shares of
Common Stock and any other securities issued in exchange of or replacement of
such shares of Common Stock (collectively, the "Common Shares"); until in the
case of any of the Common Shares (a) a Registration Statement covering such
Common Share has been declared effective by the Commission and continues to be
effective during the Effectiveness Period, or (b) such Common Share is sold in
compliance with Rule 144 or may be sold pursuant to Rule 144(k), after which
time such Common Share shall not be a Registrable Security.

            "Registration Statement" means the registration statement, including
the Prospectus, amendments and supplements to such registration statement or
Prospectus, including pre- and post-effective amendments, all exhibits thereto,
and all material incorporated by reference in such registration statement, for
the Shares required to be filed by the Company with the Commission pursuant to
this Agreement.

            "Required Filing Date" means the 120th day immediately following the
Filing Event.

            "Rule 144" means Rule 144 promulgated by the Commission pursuant to
the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.

            "Rule 158" means Rule 158 promulgated by the Commission pursuant to
the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.

            "Rule 415" means Rule 415 promulgated by the Commission pursuant to
the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.

            "Securities Act" means the Securities Act of 1933, as amended.

            "Special Counsel" means an attorney selected by and acting as
special counsel to Holder.

      2.    Registration. On or prior to the Required Filing Date, the Company
shall prepare and file with the Commission a Registration Statement covering the
resale of the Registrable Securities for an offering to be made on a continuous
basis pursuant to Rule 415. The Registration Statement shall be on Form S-3
(except if the Company is not then eligible to register for resale the
Registrable Securities on Form S-3, in which case such registration shall be on
another appropriate form in accordance with the Securities Act and the rules
promulgated thereunder) and shall contain (except if otherwise directed by ABL)
the "Plan of Distribution" attached hereto as Exhibit A. The Company shall (i)
use its commercially reasonable best efforts to cause the Registration Statement
to be declared effective under the Securities Act (including filing with the
Commission a request for acceleration of effectiveness within five (5) Business
Days of the date that the Company is notified in writing by the Commission that
the Registration

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Statement will not be "reviewed," or not be subject to further review) as soon
as possible after the filing thereof, but in any event prior to the
Effectiveness Date, and (ii) keep such Registration Statement continuously
effective under the Securities Act for a period of two years from the
Effectiveness Date (as it may be extended hereunder, the "Effectiveness
Period").

      3.    Registration Procedures; Company's Obligations.

            In connection with the registration of the Registrable Securities,
the Company shall:

            (a)   Prepare and file with the Commission on or prior to the
Required Filing Date, a Registration Statement on Form S-3 (or if the Company is
not then eligible to register for resale the Registrable Securities on Form S-3
such registration shall be on another appropriate form in accordance with the
Securities Act and the Rules promulgated thereunder) in accordance with the
method or methods of distribution thereof as specified by the Holder (except if
otherwise directed by the Holder), and use its commercially reasonable best
efforts to cause the Registration Statement to become effective and remain
effective as provided herein; provided, however, that not less than three (3)
Business Days prior to the filing of the Registration Statement or any related
Prospectus or any amendment or supplement thereto (including any document that
would be incorporated therein by reference), the Company shall (i) furnish to
the Holder and any Special Counsel, copies of all such documents proposed to be
filed, which documents (other than those incorporated by reference) will be
subject to the timely review of and comment by such Special Counsel, and (ii) at
the request of the Holder cause its officers and directors, counsel and
independent certified public accountants to respond to such inquiries, and to
make available for inspection by the Holder all financial and other records,
pertinent corporate documents and properties of the Company, as shall be
necessary, in the reasonable opinion of such Special Counsel, to conduct a
reasonable investigation within the meaning of the Securities Act. The Company
shall not file the Registration Statement or any such Prospectus or any
amendments or supplements thereto to which the Holder or any Special Counsel
shall reasonably object in writing within three (3) Business Days of their
receipt thereof.

            (b)   (i) Prepare and file with the Commission such amendments,
including post-effective amendments, to the Registration Statement as may be
necessary to keep the Registration Statement continuously effective as to the
applicable Registrable Securities for the Effectiveness Period in order to
register for resale under the Securities Act all of the Registrable Securities;
(ii) cause the related Prospectus to be amended or supplemented by any required
Prospectus supplement, and as so supplemented or amended to be filed pursuant to
Rule 424 (or any similar provisions then in force) promulgated under the
Securities Act; (iii) respond promptly to any comments received from the
Commission with respect to the Registration Statement or any amendment thereto
and promptly provide the Holder true and complete copies of all correspondence
from and to the Commission relating to the Registration Statement; and (iv)
comply in all material respects with the provisions of the Securities Act and
the Exchange Act with respect to the disposition of all Registrable Securities
covered by the Registration Statement during the applicable period in accordance
with the intended methods of disposition by the Holder set forth in the
Registration Statement as so amended or in such Prospectus as so supplemented.

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            (c)   Notify the Holder of Registrable Securities to be sold and any
Special Counsel promptly (and, in the case of (i)(A) below, not less than three
(3) Business Days prior to such filing and, in the case of (i)(C) below, no
later than the first Business Day following the date on which the Registration
Statement becomes effective) and (if requested by any such Person) confirm such
notice in writing no later than three (3) Business Days following the day (i)(A)
when a Prospectus or any Prospectus supplement or post-effective amendment to
the Registration Statement is proposed to be filed, (B) when the Commission
notifies the Company whether there will be a "review" of such Registration
Statement and whenever the Commission comments in writing on such Registration
Statement, and (C) with respect to the Registration Statement or any
post-effective amendment, when the same has become effective; (ii) of any
request by the Commission or any other Federal or state governmental authority
for amendments or supplements to the Registration Statement or Prospectus or for
additional information; (iii) of the issuance by the Commission of any stop
order suspending the effectiveness of the Registration Statement covering any or
all of the Registrable Securities or the initiation of any Proceedings for that
purpose; (iv) of the receipt by the Company of any notification with respect to
the suspension of the qualification or exemption from qualification of any of
the Registrable Securities for sale in any jurisdiction, or the initiation or
threatening of any Proceeding for such purpose; and (v) of the occurrence of any
event that makes any statement made in the Registration Statement or Prospectus
or any document incorporated or deemed to be incorporated therein by reference
untrue in any material respect or that requires any revisions to the
Registration Statement, Prospectus or other documents so that, in the case of
the Registration Statement or the Prospectus, as the case may be, it will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein,
in the light of the circumstances under which they were made, not misleading.

            The Company shall promptly furnish to the Special Counsel, without
charge, (i) any correspondence from the Commission or the Commission's staff to
the Company or its representatives relating to any Registration Statement, and
(ii) promptly after the same is prepared and filed with the Commission, a copy
of any written response to the correspondence received from the Commission.

            (d)   Use its commercially reasonable best efforts to avoid the
issuance of, or, if issued, obtain the withdrawal of, (i) any order suspending
the effectiveness of the Registration Statement, or (ii) any suspension of the
qualification (or exemption from qualification) of any of the Registrable
Securities for sale in any U.S. jurisdiction, at the earliest practicable
moment.

            (e)   If requested by the Holder, (i) promptly incorporate in a
Prospectus supplement or post-effective amendment to the Registration Statement
such information as the Company reasonably agrees should be included therein,
and (ii) make all required filings of such Prospectus supplement or such
post-effective amendment as soon as practicable after the Company has received
notification of the matters to be incorporated in such Prospectus supplement or
post-effective amendment.

            (f)   Furnish to the Holder and any Special Counsel, without charge,
at least one conformed copy of each Registration Statement and each amendment
thereto, including

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financial statements and schedules, all documents incorporated or deemed to be
incorporated therein by reference, and all exhibits to the extent requested by
such Person (including those previously furnished or incorporated by reference)
promptly after the filing of such documents with the Commission.

            (g)   Promptly deliver to the Holder and any Special Counsel,
without charge, as many copies of the Registration Statement, Prospectus or
Prospectuses (including each form of prospectus) and each amendment or
supplement thereto as such Persons may reasonably request; and the Company
hereby consents to the use of such Prospectus and each amendment or supplement
thereto by the selling Holder in connection with the offering and sale of the
Registrable Securities covered by such Prospectus and any amendment or
supplement thereto.

            (h)   Prior to any public offering of Registrable Securities, use
its commercially reasonable best efforts to register or qualify or cooperate
with the selling Holder and any Special Counsel in connection with the
registration or qualification (or exemption from such registration or
qualification) of such Registrable Securities for offer and sale under the
securities or Blue Sky laws of such jurisdictions within the United States as
the Holder reasonably requests in writing, to keep each such registration or
qualification (or exemption therefrom) effective during the Effectiveness Period
and to do any and all other acts or things necessary or advisable to enable the
disposition in such jurisdictions of the Registrable Securities covered by a
Registration Statement; provided, however, that the Company shall not be
required to qualify generally to do business in any jurisdiction where it is not
then so qualified or to take any action that would subject it to general service
of process in any such jurisdiction where it is not then so subject or subject
the Company to any tax in any such jurisdiction where it is not then so subject.

            (i)   Cooperate with the Holder to facilitate the timely preparation
and delivery of certificates representing Registrable Securities to be sold
pursuant to a Registration Statement and to enable such Registrable Securities
to be in such denominations and registered in such names as the Holder may
request at least two (2) Business Days prior to any sale of Registrable
Securities.

            (j)   Upon the occurrence of any event contemplated by Section
3(c)(v), promptly prepare a supplement or amendment, including a post-effective
amendment, to the Registration Statement or a supplement to the related
Prospectus or any document incorporated or deemed to be incorporated therein by
reference, and file any other required document so that, as thereafter
delivered, neither the Registration Statement nor such Prospectus will contain
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, in the light
of the circumstances under which they were made, not misleading.

            (k)   Use its commercially reasonable best efforts to cause all
Registrable Securities relating to such Registration Statement to be quoted by
NASDAQ and any other securities exchange, quotation system, market or
over-the-counter bulletin board, if any, on which the same securities issued by
the Company are then listed.

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            (l)   Comply in all material respects with all applicable rules and
regulations of the Commission and make generally available to its security
holders earning statements satisfying the provisions of Section 11(a) of the
Securities Act and Rule 158 not later than forty-five (45) days after the end of
any twelve (12) month period (or ninety (90) days after the end of any twelve
(12) month period if such period is a fiscal year) commencing on the first day
of the first fiscal quarter of the Company after the effective date of the
Registration Statement, which statement shall conform to the requirements of
Rule 158.

            (m)   If (i) there is material non-public information regarding the
Company which the Company's Board of Directors (the "Board") reasonably
determines not to be in the Company's best interest to disclose and which the
Company is not otherwise required to disclose, or (ii) there is a significant
business opportunity (including, but not limited to, the acquisition or
disposition of assets (other than in the ordinary course of business) or any
merger, consolidation, tender offer or other similar transaction) available to
the Company which the Board reasonably determines not to be in the Company's
best interest to disclose and which the Company would be required to disclose
under the Registration Statement, then the Company may suspend effectiveness of
a Registration Statement and suspend the sale of Registrable Securities under a
Registration Statement one (1) time every three (3) months or three (3) times in
any twelve month period, provided that the Company may not suspend its
obligation for more than sixty (60) days in the aggregate in any twelve month
period (each, a "Blackout Period"); provided, however, that no such suspension
shall be permitted for more than twenty (20) consecutive days, arising out of
the same set of facts, circumstances or transactions, and that there shall be at
least two business days between each Blackout Period; and, provided, further,
that the Effectiveness Period shall be extended by up to sixty (60) days to
reflect any Blackout Periods.

            (n)   Within two (2) Business Days after the Registration Statement
which includes the Registrable Securities is ordered effective by the
Commission, the Company shall deliver, and shall cause legal counsel for the
Company to deliver, to the transfer agent for such Registrable Securities (with
copies to the Holder whose Registrable Securities are included in such
Registration Statement) confirmation that the Registration Statement has been
declared effective by the Commission in the form attached hereto as Exhibit B.

      4.    Registration Procedures; Holder's Obligations

            In connection with the registration of the Registrable Securities,
the Holder shall:

            (a)   If the Registration Statement refers to the Holder by name or
otherwise as the holder of any securities of the Company, have the right to
require (if such reference to the Holder by name or otherwise is not required by
the Securities Act or any similar federal statute then in force) the deletion of
the reference to the Holder in any amendment or supplement to the Registration
Statement filed or prepared subsequent to the time that such reference ceases to
be required.

            (b)   (i) not sell any Registrable Securities under the Registration
Statement until it has received copies of the Prospectus as then amended or
supplemented as contemplated

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in Section 3(g) and notice from the Company that such Registration Statement and
any post-effective amendments thereto have become effective as contemplated by
Section 3(c), (ii) comply with the prospectus delivery requirements of the
Securities Act as applicable to it in connection with sales of Registrable
Securities pursuant to the Registration Statement, and (iii) furnish to the
Company information regarding such Holder and the distribution of such
Registrable Securities as is required by law to be disclosed in the Registration
Statement, and the Company may exclude from such registration the Registrable
Securities of the Holder if it fails to furnish such information within a
reasonable time prior to the filing of each Registration Statement, supplemented
Prospectus and/or amended Registration Statement.

            (c)   upon receipt of a notice from the Company of the occurrence of
any event of the kind described in Section 3(c)(ii), 3(c)(iii), 3(c)(iv),
3(c)(v) or 3(m), forthwith discontinue disposition of such Registrable
Securities under the Registration Statement until the Holder's receipt of the
copies of the supplemented Prospectus and/or amended Registration Statement
contemplated by Section 3(j), or until it is advised in writing by the Company
that the use of the applicable Prospectus may be resumed, and, in either case,
has received copies of any additional or supplemental filings that are
incorporated or deemed to be incorporated by reference in such Prospectus or
Registration Statement.

      5.    Registration Expenses

            All reasonable fees and expenses incident to the performance of or
compliance with this Agreement by the Company shall be borne by the Company
whether or not the Registration Statement is filed or becomes effective and
whether or not any Registrable Securities are sold pursuant to the Registration
Statement. The fees and expenses referred to in the foregoing sentence shall
include, without limitation, the following: (i) all registration and filing fees
(including, without limitation, fees and expenses (A) with respect to filings
required to be made with NASDAQ and each securities exchange or other market on
which Registrable Securities are required hereunder to be listed, (B) with
respect to filings required to be made with the Commission, and (C) in
compliance with state securities or Blue Sky laws); (ii) printing expenses
(including, without limitation, expenses of printing certificates for
Registrable Securities and of printing prospectuses if the printing of
prospectuses is requested by the holders of a majority of the Registrable
Securities included in the Registration Statement); (iii) messenger, telephone
and delivery expenses incurred by the Company; (iv) fees and disbursements of
counsel for the Company; and (v) fees and expenses of all other Persons retained
by the Company in connection with the consummation of the transactions
contemplated by this Agreement, including, without limitation, the Company's
independent public accountants (including the expenses of any comfort letters or
costs associated with the delivery by independent public accountants of a
comfort letter or comfort letters). In addition, the Company shall be
responsible for all of its internal expenses incurred in connection with the
consummation of the transactions contemplated by this Agreement (including,
without limitation, all salaries and expenses of its officers and employees
performing legal or accounting duties), the expense of any annual audit, and the
fees and expenses incurred in connection with the listing of the Registrable
Securities on any securities exchange as required hereunder. The Company shall
not be responsible for the payment of any commissions or other expenses incurred
by the Holder in connection with their sales of Registrable Securities or for
the fees of any Special Counsel.

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<PAGE>

      6.    Indemnification

            (a)   Indemnification by the Company. The Company shall,
notwithstanding any termination of this Agreement, indemnify and hold harmless
ABL, its permitted assignees, officers, directors, agents, brokers (including
brokers who offer and sell Registrable Securities as principal as a result of a
pledge or any failure to perform under a margin call of Common Stock),
investment advisors and employees, each Person who controls ABL or a permitted
assignee (within the meaning of Section 15 of the Securities Act or Section 20
of the Exchange Act) and the officers, directors, agents and employees of each
such controlling Person, and the respective successors, assigns, estate and
personal representatives of each of the foregoing, to the fullest extent
permitted by applicable law, from and against any and all claims, losses,
damages, liabilities, penalties, judgments, costs (including, without
limitation, costs of investigation) and expenses (including, without limitation,
reasonable attorneys' fees and expenses) (collectively, "Losses"), as incurred,
arising out of or relating to any untrue or alleged untrue statement of a
material fact contained in the Registration Statement, any Prospectus, as
supplemented or amended, if applicable, or arising out of or relating to any
omission or alleged omission of a material fact required to be stated therein or
necessary to make the statements therein (in the case of any Prospectus or form
of prospectus or supplement thereto, in the light of the circumstances under
which they were made) not misleading, except (i) to the extent, but only to the
extent, that such untrue statements or omissions are based solely upon
information regarding the Holder furnished in writing to the Company by the
Holder expressly for use in the Registration Statement, such Prospectus or such
form of Prospectus or in any amendment or supplement thereto, or (ii) as a
result of the failure of the Holder to deliver a Prospectus, as amended or
supplemented, to a purchaser in connection with an offer or sale (provided that
copies of the Prospectus, as amended or supplemented, have been provided to the
Holder by the Company for delivery to such purchaser). The Company shall notify
the Holder promptly of the institution, threat or assertion of any Proceeding of
which the Company is aware in connection with the transactions contemplated by
this Agreement. Such indemnity shall remain in full force and effect regardless
of any investigation made by or on behalf of an Indemnified Party (as defined in
Section 6(c) hereof) and shall survive the transfer of the Registrable
Securities by the Holder.

            (b)   Indemnification by ABL. ABL and its permitted assignees shall,
jointly and severally, indemnify and hold harmless the Company, its directors,
officers, agents and employees, each Person who controls the Company (within the
meaning of Section 15 of the Securities Act and Section 20 of the Exchange Act),
and the directors, officers, agents or employees of such controlling Persons,
and the respective successors, assigns, estate and personal representatives of
each of the foregoing, to the fullest extent permitted by applicable law, from
and against any and all Losses, as incurred, arising out of or relating to any
untrue or alleged untrue statement of a material fact contained in the
Registration Statement, any Prospectus, as supplemented or amended, if
applicable, or arising out of or relating to any omission or alleged omission of
a material fact required to be stated therein or necessary to make the
statements therein (in the case of any Prospectus or form of prospectus or
supplement thereto, in the light of the circumstances under which they were
made) not misleading, to the extent, but only to the extent, that (i) such
untrue statement or omission is contained in or omitted from any information so
furnished in writing by the Holder or the Special Counsel to the Company
specifically for inclusion in the Registration Statement or such Prospectus, and
(ii) such

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<PAGE>

information was reasonably relied upon by the Company for use in the
Registration Statement, such Prospectus or such form of prospectus or, to the
extent that such information relates to the Holder or the Holder's proposed
method of distribution of Registrable Securities, was reviewed and expressly
approved in writing by the Holder expressly for use in the Registration
Statement, such Prospectus or such form of Prospectus Supplement.
Notwithstanding anything to the contrary contained herein, the Holder shall be
liable under this Section 6(b) for only that amount as does not exceed the net
proceeds to the Holder as a result of the sale of Registrable Securities
pursuant to such Registration Statement.

            (c)   Conduct of Indemnification Proceedings. If any Proceeding
shall be brought or asserted against any Person entitled to indemnity pursuant
to Section 6(a) or 6(b) hereunder (an "Indemnified Party"), such Indemnified
Party promptly shall notify the Person from whom indemnity is sought (the
"Indemnifying Party) in writing, and the Indemnifying Party shall assume the
defense thereof, including the employment of counsel reasonably satisfactory to
the Indemnified Party and the payment of all fees and expenses incurred in
connection with defense thereof; provided, that the failure of any Indemnified
Party to give such notice shall not relieve the Indemnifying Party of its
obligations or liabilities pursuant to this Agreement, except (and only) to the
extent that it shall be finally determined by a court of competent jurisdiction
(which determination is not subject to appeal or further review) that such
failure shall have materially and adversely prejudiced the Indemnifying Party.

            An Indemnified Party shall have the right to employ separate counsel
in any such Proceeding and to participate in the defense thereof, but the fees
and expenses of such counsel shall be at the expense of such Indemnified Party
or Parties unless: (i) the Indemnifying Party has agreed in writing to pay such
fees and expenses; or (ii) the Indemnifying Party shall have failed promptly to
assume the defense of such Proceeding and to employ counsel reasonably
satisfactory to such Indemnified Party in any such Proceeding; or (iii) the
named parties to any such Proceeding (including any impleaded parties) include
both such Indemnified Party and the Indemnifying Party, and such Indemnified
Party shall have been advised by counsel that a conflict of interest is likely
to exist if the same counsel were to represent such Indemnified Party and the
Indemnifying Party (in which case, if such Indemnified Party notifies the
Indemnifying Party in writing that it elects to employ separate counsel at the
expense of the Indemnifying Party, the Indemnifying Party shall not have the
right to assume the defense thereof and such counsel shall be at the expense of
the Indemnifying Party). The Indemnifying Party shall not be liable for any
settlement of any such Proceeding effected without its written consent, which
consent shall not be unreasonably withheld, conditioned or delayed. No
Indemnifying Party shall, without the prior written consent of the Indemnified
Party, which consent shall not unreasonably be withheld, conditioned or delayed,
effect any settlement of any pending Proceeding in respect of which any
Indemnified Party is a party, unless such settlement includes an unconditional
release of such Indemnified Party from all liability on claims that are the
subject matter of such Proceeding.

            All reasonable fees and expenses of the Indemnified Party (including
reasonable fees and expenses to the extent incurred in connection with
investigating or preparing to defend such Proceeding in a manner not
inconsistent with this Section) shall be paid to the Indemnified Party, as
incurred, within ten (10) Business Days of written notice thereof to the
Indemnifying

                                      -10-
<PAGE>

Party (regardless of whether it is ultimately determined that an Indemnified
Party is not entitled to indemnification hereunder; provided, that the
Indemnifying Party may require such Indemnified Party to undertake to reimburse
all such fees and expenses to the extent it is finally judicially determined
that such Indemnified Party is not entitled to indemnification hereunder or
pursuant to applicable law).

            (d)   Contribution. If a claim for indemnification under Section
6(a) or 6(b) is unavailable to an Indemnified Party because of a failure or
refusal of a governmental authority to enforce such indemnification in
accordance with its terms (by reason of public policy or otherwise), then each
Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall
contribute to the amount paid or payable by such Indemnified Party as a result
of such Losses, in such proportion as is appropriate to reflect the relative
fault of the Indemnifying Party and Indemnified Party in connection with the
actions, statements or omissions that resulted in such Losses as well as any
other relevant equitable considerations. The relative fault of such Indemnifying
Party and Indemnified Party shall be determined by reference to, among other
things, whether any action in question, including any untrue or alleged untrue
statement of a material fact or omission or alleged omission of a material fact,
has been taken or made by, or relates to information supplied by, such
Indemnifying Party or Indemnified Party, and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
action, statement or omission. The amount paid or payable by a party as a result
of any Losses shall be deemed to include, subject to the limitations set forth
in Section 6(c), any reasonable attorneys' or other reasonable fees or expenses
incurred by such party in connection with any Proceeding to the extent such
party would have been indemnified for such fees or expenses if the
indemnification provided for under Section 6(a) or 6(b) was available to such
party in accordance with its terms. Notwithstanding anything to the contrary
contained herein, the Holder shall be liable or required to contribute under
this Section 6(d) for only that amount as does not exceed the net proceeds to
the Holder as a result of the sale of Registrable Securities pursuant to the
Registration Statement.

            The parties hereto agree that it would not be just and equitable if
contribution pursuant to this Section 6(d) were determined by pro rata
allocation or by any other method of allocation that does not take into account
the equitable considerations referred to in the immediately preceding paragraph.
No Person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any Person
who was not guilty of such fraudulent misrepresentation.

            The indemnity and contribution agreements contained in this Section
are in addition to any liability that the Indemnifying Parties may have to the
Indemnified Parties.

      7.    Rule 144.

            As long as the Holder owns Registrable Securities, the Company
covenants to timely file (or obtain extensions in respect thereof and file
within the applicable grace period) all reports required to be filed by the
Company after the date hereof pursuant to Section 13(a) or 15(d) of the Exchange
Act and to promptly furnish the Holder with true and complete copies of all such
filings. As long as the Holder owns Registrable Securities, if the Company is
not

                                      -11-
<PAGE>

required to file reports pursuant to Section 13(a) or 15(d) of the Exchange Act,
it will prepare and furnish to the Holder and make publicly available in
accordance with Rule 144(c) promulgated under the Securities Act annual and
quarterly financial statements, together with a discussion and analysis of such
financial statements in form and substance substantially similar to those that
would otherwise be required to be included in reports required by Section 13(a)
or 15(d) of the Exchange Act, as well as any other information required thereby,
in the time period that such filings would have been required to have been made
under the Exchange Act. The Company further covenants that it will take such
further action as the Holder may reasonably request, all to the extent required
from time to time to enable the Holder to sell the Common Shares without
registration under the Securities Act within the limitation of the exemptions
provided by Rule 144 promulgated under the Securities Act. Upon the request of
any Holder, the Company shall deliver to such Holder a written certification of
a duly authorized officer as to whether it has complied with such requirements.

      8.    Miscellaneous.

            (a)   Remedies. In the event of a breach by the Company or by the
Holder of any of their obligations under this Agreement, the Holder or the
Company, as the case may be, in addition to being entitled to exercise all
rights granted by law and under this Agreement, including recovery of damages,
will be entitled to specific performance of its rights under this Agreement. The
Company and the Holder each agree that monetary damages would not provide
adequate compensation for any losses incurred by reason of a breach by it of any
of the provisions of this Agreement and hereby further each agree that, in the
event of any action for specific performance in respect of such breach, it shall
waive the defense that a remedy at law would be adequate.

            (b)   No Inconsistent Agreements. Neither the Company nor any of its
Affiliates has as of the date hereof entered into, nor shall the Company or any
of its Affiliates, on or after the date of this Agreement, enter into, any
agreement with respect to its securities that is inconsistent with the rights
granted to the Holder in this Agreement or otherwise conflicts with the
provisions hereof. Without limiting the generality of the foregoing, without the
written consent of the Holder, the Company shall not grant to any Person the
right to request the Company to register any securities of the Company under the
Securities Act if the rights so granted are inconsistent with the rights granted
to the Holder set forth herein, or otherwise prevent the Company with complying
with all of its obligations hereunder.

            (c)   No Piggyback on Registrations. Neither the Company nor any of
its security holders (other than the Holder in such capacity pursuant hereto)
may include securities of the Company in the Registration Statement; provided,
however, that securities held by other security holders the resale of which the
Company is, prior to the Required Filing Date, contractually obligated to
register under the Securities Act may be included in the Registration Statement.

            (d)   Consent to Jurisdiction. The Company and ABL (i) hereby
irrevocably submit to the non-exclusive jurisdiction of the United States
District Court for the Central District of California and the courts of the
State of California located in the City of Los Angeles,

                                      -12-
<PAGE>

California, for the purposes of any suit, action or proceeding arising out of or
relating to this Agreement, and (ii) hereby waive, and agree not to assert in
any such suit, action or proceeding, any claim that it is not personally subject
to the jurisdiction of such court, that the suit, action or proceeding is
brought in an inconvenient forum or that the venue of the suit, action or
proceeding is improper. The Company and ABL consent to process being served in
any such suit, action or proceeding by mailing a copy thereof to such party at
the address in effect for notices to it under this Agreement and agrees that
such service shall constitute good and sufficient service of process and notice
thereof. Nothing in this Section 8(d) shall affect or limit any right to serve
process in any other manner permitted by law.

            (e)   Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the same shall be in writing and signed by the Company
and ABL.

            (f)   Notices. Any and all notices or other communications or
deliveries required or permitted to be provided hereunder shall be in writing
and shall be deemed given and effective on the earlier of (i) the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile telephone number specified for notice prior to 5:00 p.m., Pacific
Time, on a Business Day, (ii) the first Business Day after the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile telephone number specified for notice later than 5:00 p.m., Pacific
Time, on any date and earlier than 11:59 p.m., Pacific Time, on such date, (iii)
the Business Day following the date of mailing, if sent by nationally recognized
overnight courier service, or (iv) actual receipt by the party to whom such
notice is required to be given.

                  (x)   if to the Company:

                        CytRx Corporation
                        11726 San Vicente Boulevard, Suite 650
                        Los Angeles, California 90049
                        Attention: Steven A. Kriegsman
                        Telecopier: (310) 826-5529
                        Telephone: (310) 826-5648

                        with a copy to:

                        Troy & Gould Professional Corporation
                        1801 Century Park East, 16th Floor
                        Los Angeles, California 90067-2367
                        Attention: Sanford J. Hillsberg
                        Telecopier: (310) 201-4746
                        Telephone: (310) 553-4441

                                      -13-
<PAGE>

                  (y)   if to ABL:

                        Advanced BioScience Laboratories, Inc.
                        5510 Nicholson Lane
                        Kensington, Maryland 20895
                        Attention:  Johannes Burlin
                        Telecopier: (301) 984-3608
                        Telephone: (301) 881-5600

or to such other address or addresses or facsimile number or numbers as any such
party may most recently have designated in writing to the other parties hereto
by such notice.

            (g)   Successors and Assigns. This Agreement shall be binding upon
and inure to the benefit of the parties and their successors and permitted
assigns.

            (h)   Assignment of Registration Rights. The rights of the Holder
hereunder, including the right to have the Company register for resale
Registrable Securities in accordance with the terms of this Agreement, shall be
assignable by each Holder to any transferee of the Holder of all or a portion of
the shares of Registrable Securities if: (i) the Holder agrees in writing with
the transferee or assignee to assign such rights, and a copy of such agreement
is furnished to the Company within a reasonable time after such assignment; (ii)
the Company is, within a reasonable time after such transfer or assignment,
furnished with written notice of (A) the name and address of such transferee or
assignee, and (B) the securities with respect to which such registration rights
are being transferred or assigned; (iii) following such transfer or assignment
the further disposition of such securities by the transferee or assignees is
restricted under the Securities Act and applicable state securities laws; and
(iv) at or before the time the Company receives the written notice contemplated
by clause (ii) of this Section, the transferee or assignee agrees in writing
with the Company to be bound by all of the provisions of this Agreement. In
addition, the Holder shall have the right to assign its rights hereunder to any
other Person with the prior written consent of the Company, which consent shall
not be unreasonably withheld, conditioned or delayed. The rights to assignment
shall apply to the Holder (and to subsequent) successors and assigns. In the
event of an assignment pursuant to this Section 8(h), ABL shall pay all
incremental costs and expenses incurred by the Company in connection with filing
a Registration Statement (or an amendment to the Registration Statement) to
register the shares of Registrable Securities assigned to any assignee or
transferee of ABL.

            (i)   Counterparts. This Agreement may be executed in any number of
counterparts, each of which when so executed shall be deemed to be an original,
and all of which taken together shall constitute one and the same Agreement. In
the event that any signature is delivered by facsimile transmission, such
signature shall create a valid binding obligation of the party executing (or on
whose behalf such signature is executed) the same with the same force and effect
as if such facsimile signature were the original thereof.

            (j)   Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware, without regard
to principles of conflicts of

                                      -14-
<PAGE>

law thereof. This Agreement shall not be interpreted or construed with any
presumption against the party causing this Agreement to be drafted.

            (k)   Cumulative Remedies. The remedies provided herein are
cumulative and not exclusive of any remedies provided by law.

            (l)   Termination. This Agreement shall terminate on the date on
which all of the Registrable Securities may be sold without restriction pursuant
to Rule 144(k) of the Securities Act.

            (m)   Severability. If any term, provision, covenant or restriction
of this Agreement is held to be invalid, illegal, void or unenforceable in any
respect, the remainder of the terms, provisions, covenants and restrictions set
forth herein shall remain in full force and effect and shall in no way be
affected, impaired or invalidated, and the parties hereto shall use their
reasonable efforts to find and employ an alternative means to achieve the same
or substantially the same result as that contemplated by such term, provision,
covenant or restriction. It is hereby stipulated and declared to be the
intention of the parties that they would have executed the remaining terms,
provisions, covenants and restrictions without including any of such that may be
hereafter declared invalid, illegal, void or unenforceable.

            (n)   Headings. The headings herein are for convenience only, do not
constitute a part of this Agreement and shall not be deemed to limit or affect
any of the provisions hereof.

                            (signature page follows)

                                      -15-
<PAGE>

            IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed by their respective authorized persons as of the date first
indicated above.

                              CYTRX CORPORATION

                              By:  /s/ Steven A. Kriegsman
                                 -----------------------------------------------
                                  Name: Steven A. Kriegsman
                                  Title: Chief Executive Officer

                              ADVANCED BIOSCIENCE LABORATORIES, INC.

                              By:  /s/ Johannes Burlin
                                 -----------------------------------------------
                                  Name: Johannes Burlin
                                  Title: President and Chief Executive Officer

<PAGE>

                                    EXHIBIT A

                              PLAN OF DISTRIBUTION

      We are registering the shares of common stock on behalf of the selling
stockholders. The common stock may be sold in one or more transactions at fixed
prices, at prevailing market prices at the time of sale, at prices related to
the prevailing market prices, at varying prices determined at the time of sale,
or at negotiated prices. These sales may be effected at various times in one or
more of the following transactions, or in other kinds of transactions:

      -     transactions on the NASDAQ Stock Market or on any national
            securities exchange or U.S. inter-dealer system of a registered
            national securities association on which the common stock may be
            listed or quoted at the time of sale;

      -     in the over-the-counter market;

      -     in private transactions and transactions otherwise than on these
            exchanges or systems or in the over-the-counter market;

      -     in connection with short sales of the shares;

      -     by pledge to secure or in payment of debt and other obligations;

      -     through the writing of options, whether the options are listed on an
            options exchange or otherwise;

      -     in connection with the writing of non-traded and exchange-traded
            call options, in hedge transactions and in settlement of other
            transactions in standardized or over-the-counter options; or

      -     through a combination of any of the above transactions.

      The selling stockholders and their successors, including their
transferees, pledgees or donees or their successors, may sell the common stock
directly to purchasers or through underwriters, broker-dealers or agents, who
may receive compensation in the form of discounts, concessions or commissions
from the selling stockholders or the purchasers. These discounts, concessions or
commissions as to any particular underwriter, broker-dealer or agent may be in
excess of those customary in the types of transactions involved.

      The selling stockholders also may engage in short sales against the box,
puts and calls and other transactions in our securities or derivatives of our
securities and may sell or deliver shares in connection with these trades.

      In addition, any securities covered by this prospectus which qualify for
sale pursuant to Rule 144 of the Securities Act may be sold under Rule 144
rather than pursuant to this prospectus.

                                       A-1
<PAGE>

      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 after we have filed 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 and may sell the shares of common stock from time to time under this
prospectus after we have filed 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 and any broker-dealers or agents that are
involved in selling the shares of common stock may be deemed to be
"underwriters" within the meaning of the Securities Act in connection with such
sales. In such event, any commissions received by such broker-dealers or agents
and any profit on the resale of the shares of common stock purchased by them may
be deemed to be underwriting commissions or discounts under the Securities Act.

      We entered into a registration rights agreement for the benefit of the
selling stockholders to register the common stock under applicable federal and
state securities laws. The registration rights agreement provides for
cross-indemnification of the selling stockholders and us and our respective
directors, officers and controlling persons against specific liabilities in
connection with the offer and sale of the common stock, including liabilities
under the Securities Act. We will pay substantially all of the expenses incurred
by the selling stockholders incident to the registration of the common stock.

      The selling stockholders have advised us that they have not entered into
any agreements, understandings or arrangements with any underwriters or
broker-dealers regarding the sale of their shares of common stock, nor is there
an underwriter or coordinating broker acting in connection with a proposed sale
of shares of common stock by any selling stockholder. If we are notified by any
selling stockholder that any material arrangement has been entered into with a
broker-dealer for the sale of shares of common stock, if required, we will file
a supplement to this prospectus. If the selling stockholders use this prospectus
for any sale of the shares of common stock, they will be subject to the
prospectus delivery requirements of the Securities Act.

      The anti-manipulation rules of Regulation M under the Securities Exchange
Act may apply to sales of our common stock and activities of the selling
stockholders.

                                       A-2
<PAGE>

                                    EXHIBIT B

                         FORM OF NOTICE OF EFFECTIVENESS
                            OF REGISTRATION STATEMENT

[Name and address of Transfer Agent]
__________________
__________________
__________________
Attn: ____________

            Re: CytRx Corporation

Ladies and Gentlemen:

      We are counsel to CytRx Corporation, a Delaware corporation (the
"COMPANY"), and have represented the Company in connection with that certain
Collaboration Agreement (the "COLLABORATION AGREEMENT"), dated as of December
22, 2003, by and between the Company and Advanced BioScience Laboratories, Inc.,
a Delaware corporation ("ABL") pursuant to which the Company issued to ABL
shares (the "SHARES") of its Common Stock, $0.001 par value. Pursuant to the
Collaboration Agreement, the Company has also entered into a Registration Rights
Agreement with ABL (the "REGISTRATION RIGHTS AGREEMENT"), dated as of January
__, 2004, pursuant to which the Company agreed, among other things, to register
the Registrable Securities (as defined in the Registration Rights Agreement),
including the Shares, under the Securities Act of 1933, as amended (the "1933
ACT"). In connection with the Company's obligations under the Registration
Rights Agreement, on _________ __, 2004, the Company filed a Registration
Statement on Form S-3 (File No. 333-________) (the "REGISTRATION STATEMENT")
with the Securities and Exchange Commission (the "SEC") relating to the resale
of the Registrable Securities which names ABL as selling stockholder thereunder.

      In connection with the foregoing, we advise you that a member of the SEC's
staff has advised us by telephone that the SEC has entered an order declaring
the Registration Statement effective under the 1933 Act at [ENTER TIME OF
EFFECTIVENESS] on [ENTER DATE OF EFFECTIVENESS] and we have no knowledge, after
telephonic inquiry of a member of the SEC's staff, that any stop order
suspending its effectiveness has been issued or that any proceedings for that
purpose are pending before, or threatened by, the SEC and, accordingly, the
Registrable Securities are available for resale under the 1933 Act in the manner
specified in, and pursuant to the terms of, the Registration Statement.

                                               Very truly yours,

                                               By:

                                       C-1