June 8, 1998

Miravant Medical Technologies
7408 Hollister Avenue
Santa Barbara, CA  93117
U.S.A.

Attn:   Gary S. Kledzik, Ph.D.

         Re: Pharmacia & Upjohn ("P&U")/
             Miravant Medical Technologies ("Miravant") - Right of First Refusal

Dear Gary:

     We have  today  agreed to amend that  certain  Development  and  Commercial
Supply Agreement,  dated as of August 31, 1994, between Miravant and Pharmacia &
Upjohn & Co. (successor to Pharmacia,  Inc.) (such agreement,  as amended on the
date hereof, is referred to as the "Clayton  Agreement").  Under Section 16.6 of
the Clayton  Agreement,  P&U has the right to assign the Clayton  Agreement to a
third party which  acquires its production  facility in Clayton,  North Carolina
(the "Clayton  Facility").  As you were previously  informed by P&U, Pharmacia &
Upjohn Inc. has now entered into an agreement  with *****,  under which P&U will
***** its entire  worldwide  parenteral  nutrition and fluids therapy  business,
including the Clayton Facility and other production plants.

         We understand  that Miravant  consents to our assignment of the Clayton
Agreement  and  releases  P&U from all  liabilities  and  obligations  under the
Clayton Agreement from and after the effective date of such assignment,  subject
to the following:

1.   P&U shall  retain  rights to all  information  relating  to the  analytical
     methods in the DMF  relating  to the  Miravant  ***** being  developed  and
     produced at the Clayton Facility *****;

2.   ***** shall  assume in writing to Miravant all of P&U's  obligations  under
     the Clayton Agreement;

3.   ***** and P&U shall also negotiate toward a separate supply agreement under
     which ***** will supply P&U directly  its  commercial  requirements  of the
     Miravant  Product,  to the extent P&U or one or more of its  Affiliates has
     the right to sell the Miravant  Product.  If we conclude such an agreement,
     (a) Miravant will continue to supply the ***** to ***** under the terms set
     forth in the Clayton Agreement;  and (b) Miravant will continue to have all
     other  rights  and  obligations  it now has  under the  Clayton  Agreement,
     including  participation  in  the  development  of the  formulation  of the
     Miravant Product,  purchase clinical supplies,  and purchase its commercial
     requirements  of the  Miravant  Product for uses  outside of any fields for
     which P&U has marketing rights.

4.   *****

Please  indicate your consent to the assignment of the Clayton  Agreement on the
terms set forth above by signing and returning a copy of this letter.

                                           Very truly yours,

                                           PHARMACIA & UPJOHN, INC.

                                           By:/S/
                                              ----------------------------------
                                           Title:_______________________________

AGREED TO:

MIRAVANT MEDICAL TECHNOLOGIES

By:/S/
   --------------------------------------------
         Gary S. Kledzik, Chairman of the Board
         and Chief Executive Officer

***** Confidential Treatment Requested