CONSULTING AGREEMENT

          This  Consulting  Agreement is made and entered into as of the 1st day
of  April,  1998,  by and  between  Aronex  Pharmaceuticals,  Inc.,  a  Delaware
corporation  (hereinafter  referred to as the "Company") and Roman  Perez-Soler,
M.D. (hereinafter referred to as the "Consultant").

          WHEREAS,  the  Consultant  desires to provide  special  expertise  and
knowledge to the Company in the area of oncology  and  clinical  research and to
consult with the Company on such specific  research  projects in the area as may
be  agreed  on from  time  to  time  in  writing  between  the  Company  and the
Consultant, which written agreement(s) shall be incorporated herein by reference
and made a part hereof (hereinafter, the "Consulting Subjects"); and

          WHEREAS,   the  Company   desires  to  retain  the  Consultant  as  an
independent  contractor  on the terms and  conditions  hereinafter  set forth to
provide   consulting  and  advisory   services  to  the  Company  based  on  the
Consultant's special knowledge and expertise in the Consulting Subjects;

          NOW,  THEREFORE,  for and in consideration of the mutual covenants and
promises  and  representations  contained  herein,  and other good and  valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Company and the Consultant agree as follows:

          1. Expertise of Consultant.

          1.1 The  Consultant  represents  that  he has  special  expertise  and
knowledge  concerning  the  Consulting  Subjects  and that he is  willing to and
wishes to provide  his  consultation  and  advisory  services  to the Company in
connection with such area or areas.

          1.2 The Consultant  hereby represents and warrants to the Company that
the  Consultant is not a party to any agreement with any other entity and is not
bound by any  obligations to any other entity which will prevent or encumber the
Consultant  from  performing  such  services for the  Company,  except for those
agreements, if any, identified on Exhibit A hereto and approved by the Company.

          2. Independent Contractor.

          2.1 The  Consultant  hereby  agrees to perform  for the Company or any
affiliate,  parent or subsidiary of the Company and to provide to the Company or
any affiliate, parent or subsidiary of the Company his personal consultation and
advisory  services in the  Consulting  Subjects in accordance  with the terms of
this Agreement.  To the extent services pursuant to this Agreement are performed
for or at the request of an affiliate, parent, or subsidiary, the term "Company"
as used herein shall include such entity.

          2.2 Throughout the entire term of this Agreement, the Consultant shall
be an  independent  contractor  with the full power and  authority to select the
means,  method  and  manner of  performing  his  services  hereunder;  provided,
however,  that the  Consultant  will  perform  consulting  and advisory or other
services in the areas  designated by the Company.  The Consultant will in no way
be considered to be an agent, employee or servant of the Company. The Consultant
shall have no authority to bind the Company in any capacity for any purpose.

          2.3 It is not  the  purpose  or  intention  of this  Agreement  or the
parties  to  create,  and the same  shall  not be  construed  as  creating,  any
partnership,  joint venture,  agency, or employment  relationship.  However,  as
specified below, due to the nature of this independent contractor  relationship,
it is the intent of the parties  that,  during the term of this  Agreement,  the
Consultant  shall owe to the Company  fiduciary duties of the utmost loyalty and
fidelity.
<PAGE>

          3. General Duties and Compensation.

          3.1 During the term of this Agreement,  the Consultant  shall, at such
times and locations as are reasonably requested by the Company and at either the
Company's  offices,  The  University  of Texas  System  Cancer  Center  and M.D.
Anderson  Hospital  and Tumor  Institute  or such other  location or  laboratory
facilities  agreed on between the Consultant and the Company,  provide  personal
consultation and advisory services as may from time to time be agreed on between
the Company and the Consultant,  perform and supervise the performance by others
of research with respect to (a) Consulting Subjects,  and (b) any other areas of
interest on which the  Consultant  and the Company  shall  mutually  agree.  The
Consultant  shall be so  available  during the term of this  Agreement  for such
periods  as may be agreed  on from  time to time  between  the  Company  and the
Consultant, as and when specific research projects are agreed on.

          3.2 For the performance of his obligations  under this Agreement,  the
Company  shall  pay the  Consultant  a fee at the rate of  $48,000.00  per year,
one-half  of which  shall be  payable  in cash and  one-half  of which  shall be
payable in the form of a grant of the Company's  common  stock,  par value $.001
per share (the  "Common  Stock").  The cash portion of such fee shall be payable
monthly on the 15th day of each month  during  the term of this  Agreement.  The
Common Stock portion of such fee for each year during the term of this Agreement
shall be payable on April 15th of such year, and shall vest with respect to 1/12
of the  shares of Common  Stock so granted on the 15th day of each month of such
year,  subject to forfeiture of the then unvested  portion of such shares on the
expiration of the term or other  termination of this Agreement  prior to the end
of such  year.  The  number of shares of  Common  Stock to be  granted  shall be
determined by reference to the fair market value of the Common Stock as of April
1st of the year in which such grant is made,  which shall be (i) $3.50 per share
of Common Stock for the grant to be made with respect to the 1998  calendar year
and (ii) the  Average  Closing  Price  (as  defined  below)  for any  subsequent
calendar year during the term of this Agreement. For purposes of this Agreement,
the "Average  Closing  Price" as of April 1st of any year shall mean the average
closing price of the Company's  Common Stock reported on the Nasdaq Stock Market
or any  national  securities  exchange on which the Common  Stock is then listed
during the period of 10  consecutive  trading  days  ending one day before  such
date. In addition, the Company shall reimburse the Consultant for reasonable and
necessary  expenses  which are  incurred in  connection  with his  providing  of
consulting  services and with respect to which the Consultant  promptly provides
to the Company a detailed  expense  account,  provided  that any item of expense
over $1,500 has been approved by the Company in advance and in writing.

          3.3 The  Consultant  shall  himself pay, and the Company shall have no
liability  for,  all  social  security,   federal  income  taxes,   unemployment
insurance,  workmen's  compensation  insurance,  pensions,  annuities  or  other
liabilities  or taxes  incurred  by or on  behalf of or for the  benefit  of the
Consultant  or any of his agents,  employees or servants who are not employed by
the Company  arising out of the performance by the Consultant of his obligations
under this Agreement.

          4. Duty of  Faithfulness  owed by Consultant to Company During Term of
Agreement.

          4.1 During the term of this  Agreement or any extension  thereof,  the
Consultant  shall  faithfully  perform and provide the services  contemplated by
this Agreement for the Company, and the Consultant shall not perform the same or
similar services for any other entity.
<PAGE>
          4.2 In addition to the other  obligations  agreed to by the Consultant
in this Agreement,  the Consultant agrees that following the termination of this
Agreement,  he shall not at any time directly or indirectly (a) induce,  entice,
solicit any employee or  consultant of the Company to leave his  employment,  or
(b) contact, communicate or solicit any customer of the Company derived from any
customer list,  customer lead, mail, printed matter or information  secured from
the Company or its present or past employees, or (c) in any other manner use any
customer lists or customer leads, mail, telephone numbers,  printed materials or
material of the Company relating thereto.

          5. Disclosure and Ownership of Information.

          5.1 For the  purposes  of this  Agreement,  "Proprietary  Information"
shall mean all  information,  ideas,  concepts,  improvements,  discoveries  and
inventions  (including  those relating to research,  development,  financial and
sales data, pricing or trading terms,  evaluations,  opinions,  interpretations,
the identity of customers or of their requirements or of key contacts within the
customer's  organizations,   and  marketing  and  merchandising  techniques  (i)
possessed,  acquired or  developed by the Company at any time,  irrespective  of
their subject or nature, or (ii) conceived,  made,  developed or acquired by the
Consultant or disclosed or made known to the Consultant, individually or jointly
with others,  in connection with or as a result of the Consultant's  performance
under this  Agreement  that relate to the business,  products or services of the
Company and/or to the Consulting  Subjects.  The term "Proprietary  Information"
shall include, without limitation, all test data, documents,  memoranda,  notes,
records,  files,  correspondence,  drawings,  manuals,  models,  specifications,
designs, computer programs, maps and all other writings or materials of any type
embodying any of such Proprietary Information.

          5.2 All Proprietary Information is and shall be the sole and exclusive
property of the Company.

          5.3 (a)  During  the  term of this  Agreement,  the  Consultant  shall
promptly  disclose  in  writing  to  the  Company  all  Proprietary  Information
conceived, developed, made or acquired by the Consultant, either individually or
jointly with others,  whether  patentable  or not, and whether or not reduced to
practice,  irrespective  of whether the Consultant  utilized the Company's time,
data,  facilities  or material  and  irrespective  of whether  such  Proprietary
Information is conceived, developed, discovered or acquired by the Consultant on
the job, at home, or elsewhere.

          (b) The  Consultant  hereby  specifically  agrees to sell,  assign and
transfer to the Company or its nominee,  and by the execution of this  Agreement
does hereby sell, assign and transfer to the Company or its nominee,  all of his
worldwide right, title and interest in and to all of the Proprietary Information
described in Section 5.3(a),  and any United States or foreign  applications for
patents, copyrights,  certificates of invention and other industrial rights that
may be filed thereon, including divisions, continuations, continuations in part,
reissues  or  extension  thereon.  Both  during the term of this  Agreement  and
thereafter,  the Consultant  agrees to at any time assist the Company and/or its
nominee in the protection of such Proprietary Information assigned herein to the
Company  or its  nominee,  both in the  United  States  and  foreign  countries,
including,  but not  limited  to,  the  execution  of all  lawful  oaths and all
assignment documents requested by the Company or its nominee in the preparation,
prosecution,  issuance and enforcement of any  applications for United States or
foreign patents, including divisions,  continuations,  continuations in part, or
reissued  and/or  extensions  thereof,  of any  industrial  property  rights and
certificates of invention; and/or any United States or foreign rights protecting
proprietary or confidential  information.  If such assistance  takes place after
the term of this  Agreement  has expired,  the  Consultant  shall be paid by the
Company at a reasonable rate (taking into  consideration the services  performed
by the Consultant as well as the  Consultant's  normal and customary  rates) for
any time actually spent so assisting the Company or its nominee.
<PAGE>

          5.4 The Consultant  recognizes  that the protection of the Proprietary
Information  of  the  Company  against  unauthorized  disclosure  and  use is of
critical importance to the Company, and therefore,  the Consultant agrees to use
his best efforts and exercise  utmost  diligence  to protect and  safeguard  the
Proprietary  Information of the Company and its affiliates,  if any, and, except
as may be expressly  required by the Company in connection with the Consultant's
performance  of his  obligations  to  the  Company  under  this  Agreement,  the
Consultant  shall not,  either during the term of this  Agreement or thereafter,
directly or  indirectly,  use for his own benefit or for the benefit of another,
or disclose to another, any of such Proprietary Information.

          5.5 On termination of this Agreement, or at any other time on request,
the Consultant shall immediately  deliver to the Company all documents embodying
any of the Company's Proprietary Information, including all test data.

          5.6 If during the term of this Agreement,  the Consultant  creates any
work of  authorship  fixed in any  tangible  medium  of  expression  that is the
subject  matter  of  copyright  and  that  relates  to  the  Company's  (or  its
affiliate's,  if any)  business,  products,  or services,  the Company  shall be
deemed the author of such work if the work is prepared by the  Consultant in the
scope of his or her consultancy by virtue of the work being a work made for hire
or, if the work was not  prepared by the  Consultant  within the scope of his or
her  employment or  consultancy  but was  specially  ordered by the Company as a
contribution  to a  collective  work,  as a part of a  motion  picture  or other
audio-visual work, as a translation,  as a supplementary  work, as a compilation
or as an  instructional  test, then the work shall be considered to be work made
for hire and the  Company  shall be the author of the work.  With  regard to any
other work of authorship  fixed in any tangible medium of expression that is the
subject  matter of copyright  and which  relates  specifically  to the business,
products  or  services  of  the  Company  or to  the  Consulting  Subjects,  the
Consultant  agrees to, and does  hereby,  assign to the  Company  all  worldwide
right,  title and  interest in and to such  works.  Both during the term of this
Agreement and  thereafter,  the Consultant  agrees to assist the Company and its
nominee,  at any time, in the protection of the Company's worldwide right, title
and interest in and to the work and all rights of copyright therein,  including,
but not limited to, the execution of all formal assignment  documents  requested
by the  Company  or its  nominee  and the  execution  of all  lawful  oaths  and
applications  of  registration  of  copyright  in the United  States and foreign
countries.

          With regard to any work of  authorship  described  above,  the Company
agrees that it will consider and approve in its sole  discretion  such works for
publication  purposes on the request of the  Consultant,  provided that any such
publications  (i)  shall be  limited  to  scientific  publications,  (ii)  shall
identify  clearly the  relationship of the Consultant to the Company,  and (iii)
shall not be permitted if there would be, as a result of such  publication,  any
risk presented to  potentially  patentable  developments,  until steps have been
taken to protect such developments.

          5.7  Notwithstanding  anything in this Article 5 to the contrary,  the
Company  acknowledges  that the Consultant is currently,  and will be throughout
the term of this Agreement, an employee of The University of Texas System Cancer
Center,  M. D.  Anderson  Hospital and Tumor  Institute  ("Anderson"),  and that
nothing  herein  shall  interfere  or  conflict  with  any  existing  employment
agreements or  relationships  between the Consultant  and Anderson.  The Company
further  acknowledges  that the term  "Proprietary  Information,"  as defined in
Section  5.1  hereof  and as used in this  Article  5,  shall  not  include  any
information, ideas, concepts, improvements, discoveries and inventions which the
Consultant,  individually or jointly, conceives, makes, develops or acquires, or
which is  disclosed or made known to the  Consultant,  while the  Consultant  is
working  under the Research  and  Development  Contract  between the Company and
Anderson,   or  on  any  other  sponsored  research  and  development  agreement
applicable  to  Anderson,  but  shall  only  apply to such  information,  ideas,
concepts, improvements, discoveries and inventions conceived, made, developed or
required, individually or jointly, or made known or disclosed to the Consultant,
while the Consultant is engaged in performing services to the Company under this
Agreement. 
<PAGE>

          6. Term and  Termination.  

          6.1 The initial term of this Agreement  (the "Initial  Term") shall be
for a  period  of one  year  from  the  effective  date  of this  Agreement.  On
expiration of the Initial Term (and on expiration of the term of any  subsequent
extension),  the term of this  Agreement  shall  be  automatically  renewed  and
extended for an additional one-year period, unless one of the parties shall give
written  notice to the other of its  intention  to terminate  this  Agreement at
least 30 days prior to the  expiration  of the  Initial  Term or any  subsequent
one-year  extension,  in  which  case  this  Agreement  shall  terminate  on the
expiration of the Initial Term or subsequent one-year extension, as the case may
be.

          6.2  Not used.

          6.3  Termination  of this  Agreement  shall not affect  the  Company's
obligation to pay for services previously  performed by the Consultant and shall
not effect the  Consultant's  continuing  obligations to the Company in Sections
3.3,  4.2,  and  5.1  through  5.6  above,  whether  such  termination  is  made
voluntarily or involuntarily,  by the Company or the Consultant, with or without
cause.

          7. Terms Applicable to the Issuance of Common Stock.

          7.1 Unless the  offering,  sale and delivery of shares of Common Stock
issuable to the Consultant  pursuant to this Agreement have been  registered and
continue to be so at the date of exercise  hereof  under the  Securities  Act of
1933, as amended (the "Act"),  the  Consultant  agrees that the shares of Common
Stock which the  Consultant  acquires  thereby shall be acquired for  investment
without a view to distribution,  within the meaning of the Act, and shall not be
sold,  transferred,  assigned,  pledged  or  hypothecated  in the  absence of an
effective  registration  statement  for the shares of Common Stock under the Act
and  applicable  state  securities  laws or an  applicable  exemption  from  the
registration  requirements of the Act and any applicable  state securities laws.
The Consultant  also agrees that the shares of Common Stock which he may acquire
pursuant to this  Agreement  will not be sold or disposed of in any manner which
would  constitute a violation of any other applicable  securities laws,  whether
federal or state. In addition,  the Consultant  agrees (A) that the certificates
representing  the shares of Common Stock issued  under this  Agreement  may bear
such  legend or  legends as the  Company  deems  appropriate  in order to assure
compliance  with applicable  securities  laws, and (B) that the Company may give
instruction  to its transfer  agent,  if any, to stop  transfer of the shares of
Common Stock issued under this  Agreement on the stock  transfer  records of the
Company, if such proposed transfer would in the opinion of counsel  satisfactory
to the Company  constitute a violation of any  applicable  securities law or any
such agreements.
<PAGE>

          7.2 The  Consultant  hereby  represents and warrants that no provision
in, or activity contemplated by this Agreement,  including,  without limitation,
the  compensation  to be received by him  pursuant to Section  3.2,  violates or
conflicts  with any  agreement,  regulation or policy by which he is bound or to
which he is subject,  whether related to his employment or otherwise,  except as
disclosed  on  Exhibit A hereto  and agreed to by the  Company.  The  Consultant
agrees that if any such violation or conflict exists or arises in the future, he
will be solely  responsible for the  satisfactory  resolution  thereof,  without
recourse to the Company, including, without limitation, any required forfeitures
or dispositions of compensation, stock options or shares of restricted stock (or
other  unrestricted  shares held by the  Consultant).  The Consultant  agrees to
disclose  to his  employer  the  compensation  arrangements  contained  in  this
Agreement, and to provide the Company an acknowledgment thereof by such employer
or other evidence of such disclosure.

          8. Miscellaneous.

          8.1 This Agreement shall inure to the benefit of and be binding on the
respective heirs,  executors,  successors,  representatives and assigns (and, to
the extent the last  sentence of Section 2.1  applies,  affiliates,  parents and
subsidiaries)  of the  parties,  as the  case  may be;  provided,  however,  the
obligations of each party herein to the other herein are personal and may not be
assigned without the express written consent of such other party.

          8.2 The laws of the State of Texas  will  govern  the  interpretation,
validity and effect of this  Agreement  without regard to the place of execution
or the place of performance thereof,  and the courts in Houston,  Harris County,
Texas shall have personal  jurisdiction  over the Company and the  Consultant to
hear all disputes  arising out of this  Agreement and venue shall be proper with
such  courts to hear such  disputes.  In the event  either  the  Company  or the
Consultant  is not  able to  effect  service  of  process  on the  other  in any
litigation  brought in such courts with respect to such  disputes,  it is agreed
that the  Secretary  of State  for the  State of Texas  shall be an agent of the
Company and the Consultant to receive service of process.

          8.3  Notices  or  payments  given by one party to the other  hereunder
shall be deemed to have been properly given or paid if deposited with the United
States Postal Service, registered or certified mail, addressed to the Consultant
at the address  listed below his  signature on the last page hereof,  and to the
Company at the following address, or in either case to such other address as the
party  receiving  notice shall have  designated  by written  notice to the other
party:

                    Aronex Pharmaceuticals, Inc. 
                    8707 Technology Forest Place 
                    The Woodlands, Texas 77381-1191
                    Attention: Chairman

          8.4 This Agreement  replaces all previous  agreements and  discussions
relating to the subject  matters  hereof and  constitutes  the entire  agreement
between the Company and the  Consultant  with respect to the subject  matters of
this Agreement.  Without limiting the foregoing,  this Agreement  supersedes and
terminates,  effective  April 1, 1998,  the Consulting  Agreement  dated July 1,
1996, as amended, between the Company and the Consultant. This Agreement may not
be modified in any respect by any verbal statement,  representation or agreement
made by any employee,  officer  representative  of the Company or by any written
document unless it is signed by an officer of the Company.
<PAGE>

          8.5 If any term or  provision  of this  Agreement  is deemed  invalid,
contrary  to  or  prohibited   under  applicable  laws  or  regulations  of  any
jurisdiction, such provision shall be revised to the extent permitted by law and
the remaining provisions hereof shall not be invalidated.

          8.6 Both the  Consultant and the Company  recognize  that  irreparable
injury or damage  will  result to the  business of the other in the event of the
breach of any covenant herein,  and each such party therefore agrees that in the
event of such breach by it, the other party  shall be  entitled,  in addition to
any legal or  equitable  remedies and damages  available,  to an  injunction  to
restrain the violation of this  Agreement by the  breaching  party and all other
persons acting for or on behalf of the breaching party.

          IN WITNESS  WHEREOF,  the parties  have  executed  this  Agreement  in
duplicate originals effective the date first stated above.

                                        ARONEX PHARMACEUTICALS, INC.




                                        By:
 Roman Perez-Soler, M.D.
 Address:                               Geoffrey F. Cox, Ph.D
 The University of Texas                Chairman of the Board and
 M.D. Anderson Cancer Center            Chief Executive Officer
 1515 Holcombe Blvd.
 Houston, Texas 77030