July 28, 1997



Ms. Janet M. Walter
225 W. 20th Street, Apt. 4W
New York, NY  10011

Dear Janet:

I am pleased to present for your  consideration  the following  proposal to join
Aronex as Vice President,  Marketing and Business Development.  In this position
you will report  directly to me. Your  responsibilities  will  include  defining
strategy and implementing  commercialization  plans for the Company's  products.
Additional   responsibilities   include   directing  new  business   development
activities, corporate partnering, and in-licensing and out-licensing activities.
Directly  reporting to you will be Larry Hope. Joe Wyse, who oversees  contracts
and  patents  will  report to you once his  current  Pharmaceutical  Development
responsibilities  are  completed.   A  starting  date  of  August  15,  1997  is
anticipated, although I would prefer an earlier start date, if possible.

Compensation for the position would include the following:

         Base salary:         $13,333.34 monthly

         Stock Option:        100,000  options at fair market  value,  30,000 to
                              vest upon  joining  Aronex.  The balance will vest
                              over four years at a rate of 1/48 per month.

         Bonus:               A target  annual  bonus of 20% of base  salary  in
                              cash  and/or  stock  options,  dependent  upon you
                              meeting Company goals and Board approval.

         Benefits:            Benefits  would  include  medical,   dental,   and
                              disability,   401K  plan,   stock  purchase  plan,
                              medical  benefits,  cafeteria  plan,  three  weeks
                              annual  vacation,  and all other Company  benefits
                              defined in the Company's Benefits Summary which is
                              enclosed.

         Relocation:          Up to two trips to Houston to select new  housing.
                              Moving  costs of personal  property.  In order for
                              you not to have to pay for two  residences  during
                              transition,  Aronex will pay up to two months rent
                              for temporary housing in the Houston area if there
                              is overlap in your rent costs between New York and
                              Texas.  The Company will also cover gross-up costs
                              related to your  relocation  expenses that are not
                              tax deductible.


<PAGE>


Ms. Janet M. Walter                                                July 28, 1997
                                                                          Page 2


         Goals and Incentive Milestones:

                             o      In-license  product  which has  in-vitro and
                                    in-vivo  activity  and is within one year of
                                    clinical  testing.  The  incentive is 25,000
                                    options at fair market  value at the time of
                                    issuance  when the milestone is met for each
                                    compound in-licensed.

                             o      Successfully  launch  AtragenTM within three
                                    months  of NDA  approval,  or  consummate  a
                                    licensing   agreement   which  provides  the
                                    Company  with a  minimum  of $5M in  cash or
                                    equity  investment.  The incentive is 25,000
                                    options at fair market  value at the time of
                                    issuance when the milestone is met.

                                    If AtragenTM is launched by Aronex, generate
                                    a minimum  of $2M sales  within 12 months of
                                    launch.  The incentive is 25,000  options at
                                    fair  market  value at the time of  issuance
                                    when the milestone is met.

                             o       Out license NyotranTM to corporate partners
                                     in Europe and Asia and arrange co-promotion
                                     deal in North  America  which  guarantees a
                                     minimum of $20M with $15M in cash or equity
                                     investment. The Incentive is 50,000 options
                                     at  fair  market   value  at  the  time  of
                                     issuance  when the milestone is met. In the
                                     event   deals   are  done   with   regional
                                     companies   rather  than  a  multinational,
                                     incentive    payouts    are   as   follows:
                                     >=$1M=5,000 options at fair market value at
                                     the time of issuance  when the milestone is
                                     met;  >=$3M=10,000  at fair market value at
                                     the time of issuance  when the milestone is
                                     met;  >=$5M=25,000  options at fair  market
                                     value  at the  time of  issuance  when  the
                                     milestone    is    met.     Excluded    are
                                     Rhone-Poulenc   Rorer,    Pharmacia-Upjohn,
                                     Fresenius and Sanofi.

                                    In   addition   to  the  above   milestones,
                                    following  are several  objectives  that are
                                    high priority:

                                    -        Define      market       potential,
                                             positioning,     and    competitive
                                             challenges    for   each   of   the
                                             Company's products.

                                    -        Assist   in   increasing    product
                                             awareness for the Company's product
                                             ongoing opinion leading clinicians.

                                    -        Assure  that  development  programs
                                             for  each  product  isadequate  for
                                             competitive marketing positioning.

<PAGE>


Ms. Janet M. Walter                                                July 28, 1997
                                                                          Page 3

                                            

         Employment
         Agreement:           A one year  severance  package of base  salary and
                              benefits if  terminated by the Company for reasons
                              other than cause.

I believe this package is very  reasonable  and reflects the  importance  of the
position and the value we perceive you will bring to Aronex.

I hope you find this proposal  acceptable.  I look forward to you joining Aronex
as early as possible

Best regards,


By:/S/JAMES M. CHUBB, PH.D.
James M. Chubb, Ph.D.
President

JMC/cc

Enclosure


Accepted and Agreed upon this 28TH day of July, 1997 by



By:/S/JANET M. WALTER
Janet M. Walter