Holding(s) in Company

Cambridge Antibody Tech Group PLC
17 May 2004

                                  SCHEDULE 10

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES


1)   Name of company

Cambridge Antibody Technology Group plc

2)   Name of shareholder having a major interest

OrbiMed Advisors LLC

3)   Please state whether notification indicates that it is in respect of
     holding of the shareholder named in 2 above or in respect of a
     non-beneficial interest or in the case of an individual holder if it is a
     holding of that person's spouse or children under the age of 18


As in 2 above


4)   Name of the registered holder(s) and, if more than one holder, the
     number of shares held by each of them


OrbiMed Advisors LLC


5)   Number of shares/amount of stock acquired

338,000 Shares and

35,100 American Depositary Receipts

6)   Percentage of issued class

0.908%

7)   Number of shares/amount of stock disposed

None

8)   Percentage of issued class

N/A

9)   Class of security

Ordinary 10 pence shares

10)  Date of transaction

Between January 2 2004 and April 7 2004

11)  Date company informed

14 May 2004

12)  Total holding following this notification

3,010,300 of which

2,624,800 are held in the form of ordinary 10 pence shares and

385,500 are held in the form of American Depositary Receipts


13)  Total percentage holding of issued class following this notification

7.33%

14)  Any additional information

OrbiMed Advisors LLC has investment management discretion over the following
securities:



Winchester Global Trust Company Limited as Trustee for Caduccus Capital Trust
Caduccus Capital II L.P.

UBS Eucalyptus Fund L.L.C.

UBS Eucalyptus Fund Ltd

HFR SHC Aggressive Master Trust

Knightsbridge Post Venture IV L.P.

Knightsbridge Integrated Holdings, V, L.P.

Knightsbridge Netherlands II L.P.

Knightsbridge Integrated Holdings IV Post Venture LP

Knightsbridge Post Venture III LP

Knightsbridge Netherland I LP

Knightsbridge Netherlands III LP

Knightsbridge Integrated Holdings II Limited

Knightsbridge Venture Capital IV L.P.

Knightsbridge Venture Capital III LP

Finsbury Worldwide Pharmaceutical Trust plc


15)  Name of contact and telephone number for queries

Justin Hoskins 01223 898589

16)  Name and signature of authorised company official responsible for
     making this notification


Diane Mellett, Company Secretary



Date of notification: 17 May 2004


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