Rule 8.1 - Cambridge Antibody

AstraZeneca UK Limited
                  

*T 
                               FORM 8.1
      DEALINGS BY OFFERORS, OFFEREE COMPANIES OR THEIR ASSOCIATES
              FOR THEMSELVES OR FOR DISCRETIONARY CLIENTS
  (Rules 8.1(a) and (b)(i) of the City Code on Takeovers and Mergers)


1.  KEY INFORMATION

Name of person dealing (Note 1)              AstraZeneca UK Limited
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Company dealt in                             Cambridge Antibody Technology Group plc
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Class of relevant security to which the      Ordinary Shares
 dealings being disclosed relate (Note 2)
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Date of dealing                              23 May 2006
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2.  INTERESTS, SHORT POSITIONS AND RIGHTS TO SUBSCRIBE

(a) Interests and short positions (following dealing) in the class of relevant 
    security dealt in (Note 3)

                                                                  Long                               Short
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                                                 Number                        (%)      Number                     (%)
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(1) Relevant securities                          15,896,267(i)                  29.9%
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(2) Derivatives (other than options)
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(3) Options and agreements to purchase/sell
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Total                                            15,896,267(i)                  29.9%
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(i) This includes 1,400 ordinary shares and 200 ADSs held by Goldman, Sachs &
Co., and 76,684 shares held by Deutsche Bank AG, both of whom are deemed to be
acting in concert with AstraZeneca UK Limited, purchased prior to the
commencement of the Offer Period.

(b) Interests and short positions in relevant securities of the company, other
    than the class dealt in (Note 3)

           Class of relevant security:                             Long                               Short
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                                                  Number                            (%)  Number                  (%)
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(1) Relevant securities
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(2) Derivatives (other than options)
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(3) Options and agreements to purchase/sell
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Total
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(c) Rights to subscribe (Note 3)

Class of relevant security:       Details
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3.  DEALINGS (Note 4)

(a) Purchases and sales

Purchase/sale             Number of securities                               Price per unit (Note 5)
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Purchase                  5,600,000                                          1,320 pence
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(b)       Derivatives transactions (other than options)

Product name,      Long/short (Note 6)      Number of securities (Note 7)        Price per unit (Note 5)
e.g. CFD
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(c) Options transactions in respect of existing securities
(i) Writing, selling, purchasing or varying

Product name,    Writing, selling,   Number of            Exercise    Type, e.g.       Expiry        Option money
e.g. call option  purchasing,         securities to       price        American,       date          paid/received per
                  varying etc.        which the option                 European etc.                  unit (Note 5)
                                      relates (Note 7)
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(ii)Exercising

Product name, e.g. call option    Number of securities             Exercise price per unit (Note 5)
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(d) Other dealings (including new securities) (Note 4)

Nature of transaction (Note 8)      Details                         Price per unit (if applicable) (Note 5)
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4.  OTHER INFORMATION

Agreements, arrangements or understandings relating to options or derivatives
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Full details of any agreement, arrangement or understanding between the person
disclosing and any other person relating to the voting rights of any relevant
securities under any option referred to on this form or relating to the voting
rights or future acquisition or disposal of any relevant securities to which any
derivative referred to on this form is referenced. If none, this should be
stated.
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None

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Is a Supplemental Form 8 attached? (Note 9)                                  NO


Date of disclosure                                                24 May 2006
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Contact name                                                      Keith Darlington
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Telephone number                                                  020 7304 5000
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Name of offeree/offeror with which associated                     AstraZeneca UK Limited
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Specify category and nature of associate status (Note 10)         Offeror
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Notes

The Notes on Form 8.1 can be viewed on the Takeover Panel's website at
www.thetakeoverpanel.org.uk