Exhibit 10.181

MEDICAL RESEARCH COUNCIL
and
MEDIMMUNE INC.
LICENCE
For
Winter Patent

THIS AGREEMENT is made the thirteenth day of August One thousand nine hundred and ninety seven between MEDICAL RESEARCH COUNCIL of 20 Park Crescent, London WIN 4AL (hereinafter
called "MRC" which expression includes its successors and assigns) of the one part and MEDIMMUNE INC. of 35 West Watkins Mill Road, Gaithersburg, Maryland 20878, U.S.A. (hereinafter called "the
Licensee" which expression includes its successors and permitted assigns) of the other part.

WHEREAS:-

MRC
is the proprietor of certain patent rights in respect of the genetic engineering of monoclonal antibodies comprising the replacement in whole or in part of the complementarity determining regions
of one antibody by those of another.

NOW
IT IS HEREBY AGREED as follows:-

1.Definitions



---



2.Commencement



3.Grant of Rights



---



4.Payments





---



5.Term and Termination



---



6.Warranties



7.Infringement



8.Waiver



9.Notices



10.Non-assignability



11.Law and Jurisdiction



---



|Signed:                                       |  | /s/DAVID M. MOTTDavid M. Mott                                                 |  | 
|--------------------------------------------- |  | ----------------------------------------------------------------------------- |  | 
|For and on behalf of MEDIMMUNE, INC.         
|Date 8/13/97                                  |  |                                                                              
|                                              |  |                                                                               |  | 
|Signed:                                       |  | /s/MARTIN R. WOOD PH.D.Martin R. Wood Ph.D.
Head of Technology Transfer Group |  | 
|For and on behalf of MEDICAL RESEARCH COUNCIL
|Date 8/6/97                                   |  |                                                                              

---

SCHEDULE ONE above referred to

|Inventor:                |  | Gregory Paul Winter                 
|------------------------ |  | ------------------------------------
|Applicant:               |  | Medical Research Council            
|Title:                   |  | Recombinant DNA products and Methods
|UK Priority Application: |  | UK PA 8607679 (27.03.86)            

Final Application

|Territory                                                                                                                     |  | Application number
(Publication number)
*(Patent number) |  | Date of filing
(Publication date)
(Grant date)                                                          
|----------------------------------------------------------------------------------------------------------------------------- |  | -------------------------------------------------------- |  | --------------------------------------------------------------------------------------------------------
|UK                                                                                                                            |  | 8707252
(GB 2188638A)
*(GB2188638B)                      |  | 26.03.87
(7.10.87)
(23.05.90)                                                                           
|EUROPE
(Austria, Belgium, France, Germany, Greece, Italy, Liechtenstein, Luxembourg, Netherlands, Spain, Sweden, Switzerland) |  | 87/302620.7
(EP 0239400A)
*(239400)                      |  | 26.03.87
(30.09.87)
(30.08.94)                                                                          
|CANADA                                                                                                                        |  | 533071                                                   |  | 26.03.87                                                                                                
|USA (Parent)                                                                                                                  |  | 07/782717
*(5,225,539)                                   |  | 25.10.91
(06.07.93)                                                                                     
|USA
(Continuation-in-part)                                                                                                    |  | 08/452,462                                               |  | 26.05.95. This is a continuation application derived from continuation in-part 07/189814 filed 03.05.88.
|JAPAN                                                                                                                         |  | 73970/87
(296890/87)                                     |  | 27.03.87
(24.12.87)                                                                                     

---

SCHEDULE TWO above referred to

Antibodies excluded from the licence

|Antibody                                       |  | Specificity   |   | Source              
|---------------------------------------------- |  | ------------- | - | --------------------
|B72.3                                          |  | Mucin (TAG072 | ) | NIH (Schlom)        
|CTM01                                          |  | Mucin         |   | Celltarg, Belgium   
|A5B7                                           |  | CEA           |   | CRC                 
|LYM-1                                          |  | B-Cell Ag     |   | Cyanamid            
|Y22                                            |  | Fibrin        |   | Gaubius Institute   
|OKT-3 (and other Ortho antibodies against CD3) |  | CD3           |   | Ortho Pharmaceutical

---

SCHEDULE THREE above referred to

|Title                                                                                                |  | Multichain Polypeptides or Proteins and Processes for their Production     
|---------------------------------------------------------------------------------------------------- |  | ---------------------------------------------------------------------------
|Subject Matter:                                                                                      |  | Expression of multichain proteins, such as antibodies, in single hose cells
|Inventors                                                                                            |  | Michael Alan Boss
John Henry Kenten
John Spencer Emtage
Clive Ross Wood    
|Priority Applications Date: 25 March 1983
Earliest Publication Date/No: 27 September 1984/WO84/03712

|Territory            |  | Application Date |  | Application No. |  | Patent No. |  | Expiry Date
|-------------------- |  | ---------------- |  | --------------- |  | ---------- |  | -----------
|*Europe              |  | 23.03.84         |  | 84301996.9      |  | 0120694    |  | 23.03.04   
|*Europe (divisional) |  | 23.03.84         |  | 92202982.2      |  |            |  |            
|Japan                |  | 23.03.84         |  | 501609/84       |  | 2594900    |  | 23.03.04   
|Japan (divisional)   |  | 23.04.84         |  | 228332/94       |  |            |  |            
|Japan (divisional)   |  | 23.04.84         |  | 104862/97       |  |            |  |            
|USA                  |  | 23.03.84         |  | 06/672265       |  | 4816397    |  | 28.03.06   
|United Kingdom       |  | 23.03.84         |  | 8407571         |  | 2137631    |  | 23.03.04   

*includes:
Austria, Belgium, France, Germany, Italy, Liechtenstein, Luxembourg, Netherlands, Sweden, Switzerland, United Kingdom

---

QuickLinks