EXHIBIT 10.75
                         SIXTH AMENDMENT OF LEASE

      THIS SIXTH AMENDMENT OF LEASE (this "Amendment") is made as of
September 10, 1997 (the "Effective Date,,) by and between ARE-QRS CORP., a
Maryland corporation ("Landlord"), and MEDIMMUNE, INC., a Delaware corpo
ration ("Tenant").


                     EXPLANATORY STATEMENT

      A.  Clopper Road Associates ("Original Landlord") and Tenant entered
into a Lease Agreement dated February 14, 1991 (the "Original Lease"),
whereby Tenant agreed to lease from Landlord forty thousand eight hundred
forty-three (40,843) square feet (the "Original Leased Premises") in the
building (the "Building") known as Building D located at 35 West Watkins
Mill Road, in the Bennington Corporate Center in Gaithersburg, Maryland.

      B.  Original Landlord and Tenant entered into a First Amendment of
Lease dated June 8, 1993 (the "First Amendment"), pursuant to which
Building D was expanded and the square footage of the original Leased
Premises was increased by the amount of such expansion (the "Expansion
Space") (collectively, the Original Leased Premises and the Expansion Space
shall be hereinafter referred to as the "Expanded Leased Premises").
Certain other changes were also made to the Original Lease as a result of
the First Amendment.

      C.  Original Landlord and Tenant entered into a Second Amendment of
Lease dated June 30, 1993 (the "Second Amendment"), pursuant to which the
square footage of the Expanded Leased Premises was increased by adding
space (the "Second Expansion Space") in Building 3 located at 25 West
Watkins Mill Road (collectively, the original Leased Premises, the
Expansion Space and the Second Expansion Space are hereinafter referred to
as the "Second Expanded Leased Premises'); the Rent payable was adjusted,
and certain other changes were made to the original Lease, as amended.

      D.  Original Landlord and Tenant entered into a Third Amendment of
Lease dated April 15, 1996, but effective as of January 1, 1995 (the "Third
Amendment") to adjust percentages and addresses set forth in the Original
Lease as amended.

      E.  Original Landlord and Tenant entered into a Fourth Amendment of
Lease dated October 3, 1996 (the "Fourth Amendment") pursuant to which the
portion of the Second Expanded Leased Premises in Building B was expanded
by adding space adjacent thereto (the "VAD Space") (the Second Expanded
Leased Premises, as expanded by the VAD Space is hereinafter referred to as
the 'Third Expanded Leased Premises,,); the Rent was adjusted, and certain
other changes were made to the Original lease, as amended.



      F.  Original Landlord and Tenant entered into a Fifth Amendment of
Lease dated October 3, 1996 (the "Fifth Amendment") pursuant to which the
portion of the Third Expanded Leased Premises in Building D was expanded by
adding space adjacent thereof (the "Building D Expansion Space") (the Third
Expanded Leased Premises, as expanded by the Building D Expansion Space, is
hereinafter referred to as the "Fourth Expanded Leased Premises"; the Rent
was adjusted, and certain other changes were made to the Original Lease, as
amended.

      G.  The Original Lease, the First, Second, Third, Fourth and Fifth
Amendments are hereinafter collectively referred to as the "Lease".

      H.  Landlord purchased the Project from original Landlord.

      I.  Landlord now desires to lease to Tenant and Tenant desires to
lease from Landlord additional space in Building B located at 25 West
Watkins Mill Road;

      J.   Landlord and Tenant also desire to adjust the Rent payable under
the Lease and make certain other changes to the Lease, all as more
specifically set forth below.

      NOW, THEREFORE, in consideration of the Explanatory Statement, which
shall be deemed a substantive part of this Sixth Amendment, the covenants
of the parties herein and in the Lease, and other good and valuable
consideration, the receipt and adequacy of which are hereby acknowledged,
Landlord and Tenant hereby agree as follows:

      1.  Effective Date of Sixth Amendment.  From and after the date of
this Sixth Amendment, the Lease shall be amended as set forth below.

      2.  Capitalized Terms. ALL capitalized terms in this Sixth Amendment
shall have the same meanings as those in the Lease, unless specifically set
forth otherwise herein.

      3.  1997 Additional Space.  Landlord hereby leases to Tenant, and
Tenant hereby leases from Landlord, in addition to the Fourth Expanded
Leased Premises, Ten Thousand Seventy Three (10,073) rentable square feet
of space in Building 3 located at 25 West Watkins Mill Road (the 111997
Additional Space") (collectively, the Fourth Expanded Leased Premises and
the 1997 Additional Space shall be deemed the "Leased Premises").  The 1997
Additional Space is shown more particularly on Exhibit A attached hereto
and made a part hereof.

      On or before the 1997 Additional Space Commencement Date (as defined
in Section 4(a) below), Landlord's architect and Tenant's architect shall
jointly measure the rentable square footage of the 1997 Additional Space in
accordance with the Building Owners and Managers Association method of
measurement (ANSI 265.11996) and shall jointly certify to Landlord and
Tenant the rentable square footage of the 1997 Additional Space.  If
necessary, appropriate rental and other adjustments shall be made by way of
an amendment to the Lease.

      Landlord hereby agrees that the Second Expansion Space, the VAD Space
and the 1997 Additional Space need not be separate and distinct premises
and, subject to compliance by Tenant with the provisions of the Lease
governing alterations, may be altered, reconfigured or redesigned to
comprise a single integrated premises.

4. Construction of-1997 Additional Space

      (a) Landlord shall deliver the 1997 Additional Space to Tenant on the
day following the date of delivery by Landlord to Tenant of a fully
executed copy of this Amendment (the 111997 Additional Space Commencement
Date").  Tenant hereby acknowledges that it has inspected the 1997
Additional Space and that it is in an unfinished state and Tenant hereby
agrees to accept the 1997 Additional Space in "as is" condition on the date
hereof reasonable wear and tear excepted between the date hereof and the
date of delivery to Tenant.

      (b) Tenant shall cause the improvements for the 1997 Additional Space
(the 111997 Additional Space Construction") to be constructed in accordance
with the plans and specifications for the 1997 Additional Space (the 111997
Additional Space Plans").  The 1997 Additional Space Plans shall be
approved and initialed by the parties before construction begins.  Landlord
shall not unreasonably withhold or delay its approval of the 1997
Additional Space Plans.  Tenant shall provide Landlord one copy of all the
1997 Additional Space Plans at Tenant's expense, before construction
begins.

      Tenant shall have received a building permit from the City of
Gaithersburg for the 1997 Additional Space, and shall have provided a copy
to Landlord, before Tenant shall be authorized to begin construction under
this Sixth Amendment.

      Before construction begins Tenant shall have furnished to Landlord
insurance certificates evidencing the existence of all insurance policies
required to be carried by Tenant pursuant to the Lease.

      (c) (i) Subject to Landlord's approval, which approval shall not be
unreasonably withheld or delayed, Tenant shall select a contractor (the
"Third Party Contractor") to construct the 1997 Additional Space improve
ments.  Tenant will not change the Third Party Contractor to another party
without the prior written consent of Landlord, which consent shall not be
unreasonably withheld or delayed.  The Third Party Contractor shall provide
all work, labor and materials in support of the 1997 Additional Space
Construction in accordance with the 1997 Additional Space Plans.  The Third
Party Contractor shall also perform its work in strict compliance with all
laws, rules, regulations, orders, codes and other requirements of all
governmental and quasi-governmental authorities having jurisdiction with
respect to the 1997 Additional Space and/or the performance of the 1997
Additional Space Construction, and shall comply with all of Landlord's
reasonable rules and regulations provided to the Third Party Contractor.

          (ii) In addition, Tenant shall cause the Third Party Contractor
to obtain Builder's Risk insurance naming Landlord and Tenant as additional
insureds and public liability insurance with limits of $1,000,000/
$2,000,000 for the 1997 Additional Space Construction.  No later than the
date of commencement of the 1997 Space Construction, Tenant shall cause the
Third Party Contractor to provide to Landlord original insurance certif
icates evidencing all such insurance policies and proof that the Third
Party Contractor maintains a policy of Worker's Compensation Insurance in
accordance with applicable law.

         (iii) Landlord, without charge to Tenant, shall have the right to
observe the Third Party Contractor's work on the 1997 Additional Space
Construction.

      (d) Landlord shall contribute $75,000.oo (the "Allowance") toward the
costs and expenses incurred in connection with the performance of the 1997
Additional Space Construction.  The Allowance shall be paid by Landlord to
Tenant upon the completion of the 1997 Additional Space Construction.  The
1997 Additional Space Construction shall be completed at such time as
Tenant,. at its sole cost and expense and without cost to Landlord (except
for the Allowance) shall (1) furnish evidence satisfactory to Landlord that
all of the 1997 Additional Space Construction has been completed and paid
for in full (which may be evidenced by the architect's certificate of
completion and final waiver and release of liens from all contractors,
subcontractors and materialmen (and such work has been accepted by
Landlord); that any and all liens therefor that have been or might be filed
have been discharged of record (by payment, bond, order of a court of
competent jurisdiction or otherwise) or waived, and that no security
interests relating thereto are outstanding; (2) furnish to Landlord all
certifications and approvals with respect to the 1997 Additional Space
Construction that may be required from any governmental authority and any
board of fire underwriters or similar body for the use and occupancy of the
1997 Additional Space; and (3) furnish an affidavit from Tenant's architect
certifying that all work performed in the 1997 Additional Space is in
substantial accordance with the 1997 Additional Space Plans approved by
Landlord.

      5.  Certain Constructions Provisions Not Applicable to 1997
Additional Space.  Article I.B of the Original Lease, Paragraphs 4 through
7 of the First Amendment and Paragraph 5 of the Second Amendment shall not
apply to the 1997 Additional Space, except as may be specifically set forth
in this Sixth Amendment.

      6.  Term of 1997 Additional Space Lease.  The 1997 Additional Space
Lease Term will commence on the 1997 Additional Space Commencement Date,
and will end on November 30, 2006, subject to Paragraph 7 below.  From and
after the date of this Sixth Amendment, the term "Lease Term" will include
the 1997 Additional Space Lease Term.

      7. Cancellation Option

         (a)   Paragraph II.B of the Original Lease, as amended by the
First Amendment, and as amended by the Second Amendment (with respect only
to the Expanded Leased Premises (as defined in the Second Amendment)) shall
not apply to the 1997 Additional Space.

         (b)   Provided that no event of default shall have occurred and be
continuing, Tenant shall have the right to terminate the Lease with respect
to the 1997 Additional Space at any time from and after November 30, 2001
upon at least 180 days prior written notice to Landlord, which notice shall
be accompanied by a termination fee in an amount equal to $38,256.00 plus
an amount equal to three (3) months Basic Annual Rent payable hereunder on
the date of Tenant's notice in respect of the 1997 Additional Space, if the
termination date is November 30, 2001.  The termination fee payable by
Tenant to Landlord shall be reduced by $620.88 per month after December 1,
2001.  So long as Tenant pays the Basic Annual Rent and Additional Rent
payable under the Lease through the termination date set forth in Tenant's
notice, the Lease as it relates to the 1997 Additional Space shall expire
and come to an end on such termination date as if such date were the end of
the Lease Term.

      8.   Basic - Annual Rent for the 1997 Additional Space.  Basic Annual
Rent for the 1997 Additional Space shall equal One Hundred Thirty-five
Thousand Nine Hundred Eighty Five and 56/100 Dollars ($135,985.56) per
annum, payable in equal monthly installments of Eleven Thousand Three
Hundred Thirty Two and 13/100 Dollars ($11,332.13).  Payment of Basic
Annual Rent shall commence on November 10, 1997.

         9 .   Rent.

         (a) The Basic Annual Rent shall be increased each  year by an
amount equal to three percent (3%) of the Basic Annual Rent then in effect.
The first such adjustment shall become effective December 1, 1998, and
subsequent adjustments shall become effective on December 1 of every
calendar year thereafter for so long as the Lease continues in effect.

         (b)   The above amounts of Basic Annual Rent for the 1997
Additional Space shall be paid at the same time and in addition to the
payment of Basic Annual Rent for the balance of the Leased Premises, and
otherwise in the manner set forth in Article III.B of the Lease.

         (c) There shall be no Security Deposit required hereunder for the
1997 Additional Space.



          10. Adjustments to Square Footages and Percentages.

         (a)   Paragraph III.C(l)(c) of the Lease shall be amended so that
the term "Rentable Area of the Leased Premises,' shall be deemed to be
81,298 square feet (being Fifty Eight and Fifty One One Hundredths Percent
(58-51%) of the Buildings) so that the term includes the 1997 Additional
Space.  This amended square footage number shall apply throughout the Lease
to all references to the square footage of the Leased Premises.

(b)   Notwithstanding anything to the contrary continued in the
Lease, including this Amendment, for the purpose of calculating Additional
Rent payments in respect of Common Area Expenses, Taxes and Insurance
Tenant's Portion shall be Fifty One and Twenty Six one Hundredths Percent
(51.26%) and the term Tenant's Portion shall not include the 1997
Additional Space.  The term "Tenant's 1997 Additional Space Portion" shall
mean Seven and Twenty Five One Hundredths Percent (7.25%). Tenant shall pay
to landlord, as Additional Rent in respect of the 1997 Additional Space,
Tenant's 1997 Additional Space Portion of Common Area Expenses, Taxes and
Insurance. Payments by Tenant of Additional Rent in respect of the 1997
Additional Space shall be made monthly commencing on the date upon which
Basic Annual Rent in respect of the 1997 Additional Space commences and
shall be payable on the first day of each calendar month thereafter, each
such payment to be in an amount equal to one-twelth (1/12th) of the amount
of such expenses for the applicable calendar year as estimated by Landlord.
Payments of Tenant's 1997 Additional Space Portion in respect of Common
Area Expenses shall not increase in any one year by more than eight percent
(8%).
      11. Use Restrictions and Rules.  Paragraph IV.A of the Original Lease
shall apply to the 1997 Additional Space.

      12. Improvements-by Tenant.  Subsection (i) of the second paragraph
of Paragraph IV.B of the Lease shall be stricken in its entirety and
replaced with the following:

          "(i) the aggregate cost of the same does not exceed One Hundred
Thousand Dollars ($100,000) with respect to the Expanded Leased Premises,
Fifty Thousand Dollars ($50,000) with respect to the Second Expansion
Space, Fifty Thousand Dollars ($50,000) with respect to the VAD Space,
Fifty Thousand Dollars ($50,000) with respect to the Building D Expansion
Space, or Fifty Thousand Dollars ($50,000) with respect to the 1997
Additional Space ....

      13. Insurance.  Paragraph IV.E of the original Lease shall apply to
the 1997 Additional Space.

      14. Damage and Destruction.  The last two paragraphs of Article VI
of the Lease shall be amended to read as follows:



         "Notwithstanding the preceding three (3) paragraphs of this
Article VI, if Landlord or Tenant has the right to terminate the Lease
pursuant to this Article VI due to damage or destruction to the Expanded
Leased Premises and Building D Expansion Space only (excluding the Second
Expansion Space, the VAD Space and the 1997 Additional Space) by fire,
other casualty, or any other cause (except condemnation), then Landlord or
Tenant automatically shall have the right pursuant to this Article VI to
terminate the Lease with respect to the Second Expansion Space, the VAD
Space and the 1997 Additional Space regardless of whether the Second
Expansion Space and/or the VAD Space and/or the 1997 Additional Space has
suffered any damage or destruction.  However, if Landlord or Tenant has the
right to terminate the Lease pursuant to this Article VI due to damage or
destruction to the Second Expansion Space and/or the VAD Space and/or the
1997 Additional Space only, (excluding the Expanded Leased Premises and
Building D Expansion Space), Landlord or Tenant shall not have any right to
terminate the Lease with respect to the Expanded Leased Premises and
Building D Expansion Space.  If Landlord or Tenant duly terminates the
Lease under Article VI with respect to the Second Expansion Space and/or
the VAD Space and/or the 1997 Additional Space, the Lease shall remain in
full force and effect with respect to the Expanded Leased Premises and
Building D Expansion Space, and the Second Expansion Space and/or the VAD
Space and/or the 1997 Additional Space shall be stricken from the
definition of "Leased Premises" under the Lease.  Upon such damage or
destruction to the Second Expansion Space and/or the VAD Space and/or the
1997 Additional Space, the parties agree to enter into an amendment to the
Lease setting forth the reduced Leased Premises and other related changes
to the Lease, including, without limitation, reduction of Basic Annual Rent
and Tenant's Portion of Common Area Expenses, Taxes and Insurance.

      Notwithstanding anything set forth above in this Article VI, if
Landlord or Tenant has the right to terminate the Lease pursuant to this
Article VI due to damage or destruction to one of the Second Expansion
Space or the VAD Space or the 1997 Additional Space, then Landlord or
Tenant shall not have the right to terminate the Lease under this provision
with respect to the nondamaged Space in Building B, or with respect to the
Expanded Leased Premises.,,

      15. Condemnation.  The last sentence of the second paragraph of
Article VII of the Lease shall only apply to the Expanded Leased Premises
and Building D Expansion Space and shall not apply to the Second Expansion
Space, or the VAD Space or the 1997 Additional Space.  In addition, the
last two paragraphs of Article VII of the Lease shall be amended to read as
follows:

         "Notwithstanding the preceding two (2) paragraphs of this Article
VII, if Landlord or Tenant has the right to terminate the Lease pursuant to
this Article VII due to taking or condemnation of the Expanded Leased
Premises and Building D Expansion Space only (excluding the Second
Expansion Space, the VAD Space and the 1997 Additional Space), then
Landlord or Tenant automatically shall have the right pursuant to this
Article VII to terminate the Lease with respect to the Second Expansion
Space, VAD Space, and the 1997 Additional Space, regardless of whether the
Second Expansion Space and/or the VAD Space and/or the 1997 Additional
Space has been condemned in whole or in part.  However, if Landlord or
Tenant has any right to terminate the Lease pursuant to this Article VII
due to condemnation or taking of the Second Expansion Space and/or the VAD
Space and/or the 1997 Additional Space only (excluding the Expanded Leased
Premises and Building D Expansion Space), Landlord or Tenant shall not have
the right to terminate the Lease with respect to the Expanded Leased
Premises and Building D Expansion Space.  If Landlord or Tenant duly
terminates the Lease under Article VII with respect to the Second Expansion
Space and/or the VAD Space and/or the 1997 Additional Space the Lease shall
remain in full force and effect with respect to the Expanded Leased
Premises and Building D Expansion Space and the Second Expansion Space
and/or VAD Space and/or the 1997 Additional Space shall be stricken from
the definition of "Leased Premises" under the Lease.  Upon such
condemnation of the Second Expansion Space and/or the VAD Space and/or the
1997 Additional Space the parties agree to enter into an amendment to the
Lease setting forth the reduced Leased Premises and other related changes
to the Lease, including, without limitation, a reduction of Basic Annual
Rent and Tenant's Portion of Common Area Expenses, Taxes and Insurance.

         Notwithstanding anything set forth above in this Article VII, if
Landlord or Tenant has the right to terminate the Lease pursuant to this
Article VII due to taking or condemnation of one of the Second Expansion
Space or the VAD Space or the 1997 Additional Space, then Landlord or
Tenant shall not have the right to terminate the Lease under this provision
with respect to the noncondemned Space in Building B, or with respect to
the Expanded Leased Premises.

      16. Parkincr.  Parking under the Lease shall not be modified pursuant
to this Sixth Amendment.

      17. Renewal Option.  Rider No. 1 to the Lease shall apply to the 1997
Additional Space.

      18. Tenant Authorization.  Tenant represents and warrants to Landlord
that this Sixth Amendment has been validly authorized and is executed by an
authorized officer of Tenant and that its terms are binding upon and
enforceable against Tenant in accordance herewith.

      19. Brokers.  Landlord and Tenant represent and warrant that there is
no real estate broker or agent representing Tenant in connection with this
Sixth Amendment.

      20. Lease as Amended.  From and after the full execution of this
Sixth Amendment, the Lease shall be amended and in full force and effect in
such respects as are set forth in this Sixth Amendment, and all other
provisions, terms, conditions and riders of and to the Lease shall in all
respects remain as set forth in the Lease, in full force and effect and
applicable to the 1997 Additional Space, except as specifically set forth
in this Sixth Amendment.

      21. Reaffirmation of Lease.  Each of Tenant and Landlord hereby
reaffirms and restates, and agrees to be bound by, the covenants, promises,
representations and agreements set forth in the Lease (except to the extent
that they are expressly superseded by this Sixth Amendment) as if made
herein.



LANDLORD:

ARE-QRS CORP.

By:/s/Allan D. Gold
Name: Allan D. Gold
Title: President



MEDIMMUNE, INC.,
a Delaware corporation

By:/s/David M. Mott
Name: David M. Mott
Title: President