| abstract |
The invention concerns quinazoline derivatives of Formula (I), wherein each of R1a, R1b, R2, R3 and a have any of the meanings defined in the description; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use as an antiproliferative agent in the prevention or treatment of tumours which are sensitive to inhibition of erbB receptor tyrosine kinases. |