EXHIBIT 10.61

                    THIRD AMENDMENT OF LEASE
                                
          THIS THIRD AMENDMENT OF LEASE (this "Amendment") is
made this 15th day of April, 1996 but shall be deemed effective
as of January 1, 1995 (the "Effective Date") by and between
CLOPPER ROAD ASSOCIATES, a Maryland joint venture ("Landlord")and
MEDIMMUNE, INC., a Delaware corporation("Tenant").


                          INTRODUCTION
                                
          A.  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.  Landlord and Tenant entered into a First Amendment
of Lease dated June 8, 1993 (the "First Amendment") , pursuant to
which Building ID 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 be the "Expanded Leased Premises" . Certain other
changes were also made to the Original Lease as a result of the
First Amendment.

          C.  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 "Additional Space") in Building B
located at 25 West Watkins Mill Road (collectively, the original
Leased Premises, the Expansion Space and the Additional Space are
hereinafter referred to as the "Leased Premises"); the Rent
payable was adjusted, and certain other changes were made to the
original Lease.

          D.  The Original Lease, the First Amendment and the
Second Amendment are herein collectively referred to as the
"Lease".

          E.  As a result of changes in the size of the Project,
Landlord and Tenant desire to adjust the square footages,
percentages and addresses in the Lease, and modify certain other
provisions of the Lease as more specifically set forth below.

       NOW, THEREFORE, in consideration of the Introduction,
which is deemed a substantive part of this 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.  Adjustments to Square Footages, Percentages and
Addresses

       (a)  Paragraph III.C.1(a) is amended by striking the
phrase after "Phase 3" in its entirety and replacing it with "
Buildings A and E (15 and 50 West Watkins Mill Road)."

      (b)  Paragraph III.C.l(b) is amended so that the term
"Rentable Area of the Buildings" will be deemed to be 137,222
square feet rather than 134,546 square feet in Paragraph
111.C.1(b) and throughout the Lease.

      (c)  Paragraph III.C.l(e) is amended so that the term
"Tenant's Portion" will be forty-two and thirty-one hundredths
percent (42.31%) (58,054/137,222), computed on the basis of the
ratio of the Rentable Area of the Leased Premises to the Rentable
Area of the Buildings.  This amended Tenant's Portion shall apply
throughout the Lease.

       2.  Notices.  Paragraph X.G. of the Lease is hereby
deleted in its entirety and replaced with the following new
section:

       "X.G.  Notices. Except as otherwise provided in this
       Lease, any requirement for a notice, demand or request
       under this Lease will be satisfied by a writing (a) hand
       delivered with receipt; (b) mailed by United States
       registered or certified mail or Express Mail, return
       receipt requested, postage prepaid; or (c) sent by Federal
       Express or any other nationally recognized overnight
       courier service, and addressed: (i) if to Landlord, c/o
       Manekin Corporation, 7470 New Technology Way, Frederick,
       Maryland 21703, with copies to: Manekin Corporation, 7165
       Columbia Gateway Drive, Columbia, Maryland 21046,
       Attention: General Counsel and to Ann Clary Gordon,
       Esquire c/o Shapiro and Olander, 36 South Charles Street,
       Baltimore, Maryland 21201; and (ii) if to Tenant, at the
       Leased Premises.  All notices that are sent in accordance
       with this Paragraph X.G. will be deemed received by the
       other party on the earliest of the following applicable
       time periods: (a) three business days after being mailed
       in the aforesaid manner; (b) the date the return receipt
       is executed; or, (c) the date delivered as documented by
       the overnight courier service or the hand delivery
       receipt.  All rental payments and other charges payable
       by Tenant under this Lease will be delivered to Landlord
       at 7165 Columbia Gateway Drive, Columbia, Maryland 21046,
       Attention: Accounting Department.  Either party may
       designate a change of address by written notice to the
       other party."
       
       3.  Amendment.  As of and after the date hereof, the Lease
shall be amended and in full force and effect in such respects as
are set forth in this Amendment, and all other provisions, terms,
conditions and riders of and to the Lease shall in all respects
remain in full force and effect as set forth in the Lease.

       4.  Reaffirmation.  Tenant 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 Amendment)
as if made herein.

      5. Defined Terms.  Unless otherwise defined herein or
unless the context requires a contrary meaning, all capitalized
terms used in this Amendment shall have the meanings given to
them in the Lease.

       6.  Authority.  Tenant represents and warrants to Landlord
that the Lease and this Amendment were approved by all necessary
parties, were validly executed by all necessary officers of
Tenant, and are and remain binding upon and enforceable against
Tenant in accordance with their terms, and that the name and
address of Tenant's resident agent in the State of Maryland are
The Corporation Trust Incorporated, 32 South Street, Baltimore,
Maryland 21202.

       IN WITNESS WHEREOF, Landlord and Tenant have respectively
signed this Third Amendment of Lease under seal as of the day and
year first above written, intending to be bound as of the
Effective Date.

WITNESS/ATTEST:                CLOPPER ROAD ASSOCIATES
                              By: M.O.R.M. Associates Limited
Partnership
                              By: RA & PM, Inc.
Barbara C. Slade              By:  Alton D. Fryer(SEAL)
                              Name:  Alton D. Fryer
                              Title:  Vice President
                                      LANDLORD



WITNESS/ATTEST:                 MEDIMMUNE, INC.
Jayne L. Korolkoff              By:  David LeBuhn(SEAL)
                                Name:  David LeBuhn
                                Title:  Treasurer
                                         TENANT


STATE OF MARYLAND             )
                              )  TO WIT:
COUNTY/CITY OF Frederick      )

       I HEREBY CERTIFY that on this 19th day of April, 1996,
before me, the subscriber, a Notary Public of the State of
Maryland and County/City of Frederick, personally appeared before
me Alton Fryer, Vice President, of RA & FM, Inc., a general
partner of M.O.R.M. Associates Limited Partnership, a general
partner of CLOPPER ROAD ASSOCIATES, Landlord, and s/he
acknowledged the foregoing Fourth Amendment of Lease to be the
act and deed of said joint venture.


       WITNESS my hand and notarial seal.

                                     Betty A. Frankel
                                     Notary Public
                                     Frederick Co., MD

My Commission Expires December 5, 1997.



STATE OF MARYLAND             )
                              )  TO WIT:
COUNTY/CITY OF MONTGOMERY/Gaithersburg)


       I HEREBY CERTIFY that on this 15th day of April, 1996,
before me, the subscriber, a Notary Public of the State of
Maryland and County/City of Montgomery/Gaithersburg, personally
appeared before me David LeBuhn, who acknowledged her/himself to
be the Treasurer of MEDIMMUNE, INC., Tenant and she/he
acknowledged the foregoing Fourth Amendment of Lease to be the
act and deed of said corporation.

       WITNESS my hand and notarial seal.


                                     Carol A. Iorio
                                     Notary Public


My Commission Expires:  July 11, 1998