Holding(s) in Company

Cambridge Antibody Tech Group PLC
18 May 2006

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of company



CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC



2. Name of shareholder having a major interest



GENZYME CORPORATION



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 ABOVE



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



AS ABOVE



5. Number of shares / amount of stock acquired



N/A



6. Percentage of issued class



N/A



7. Number of shares / amount of stock disposed



380,000



8. Percentage of issued class



0.714%



9. Class of security



ORDINARY 10 PENCE SHARES



10. Date of transaction



16 MAY 2006






11. Date company informed



18 MAY 2006



12. Total holding following this notification



4,108,668



13. Total percentage holding of issued class following this notification



7.723%



14. Any additional information



NONE



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



JUSTIN HOSKINS, COMPANY SECRETARY



Date of notification



18 MAY 2006



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