The invention provides a compound of the formula (1):or a salt, solvate, N-oxide or tautomer thereof； wherein either R1is R1aand R2is R2a； or R1is R1band R2is R2b； provided that in each case at least one of R1and R2is other than hydrogen； R1aand R2aare the same or different and each is selected from hydrogen, C1-4alkyl, C2-4alkenyl and C2-4alkynyl wherein the C1-4alkyl is optionally substituted by C1-2alkoxy； R1band R2bare the same or different and are selected from hydrogen, C(O)NR4R5, C(O)R6and C(O)OR6where R6is C1-4alkyl, R4and R5are both C1-4alkyl, or NR4R5forms a 4 to 7 membered saturated heterocyclic ring optionally containing a second heteroatom ring member selected from O, N or S and oxidised forms of N and S, the heterocyclic ring being optionally substituted by one or two C1-4alkyl groups and/or one or two oxo groups； and R3is a group D:wherein the asterisk denotes the point of attachment to the isoindoline ring； but excluding acetic acid 5-acetoxy-4-isopropyl-2-[5-(4-methyl-piperazin-1-ylmethyl)-1,3-dihydro-isoindol e-2-carbonyl]-phenyl ester.本發明提供式(1)化合物：或其鹽，溶劑化物，N-氧化物或互變體，其中R1為R1a且R2為R2a；或者R1為R1b且R2為R2b；惟在每一情況下，R1及R2中至少有一者不為氫；R1a及R2a乃相同或互異且各自擇自氫，C1-4烷基，C2-4烯基及C2-4炔基，其中C1-4烷基乃隨意地經C1-2烷氧基取代；R1b及R2b乃相同或互異且擇自氫，C(O)NR4R5，C(O)R6及C(O)OR6，其中R6為C1-4烷基，R4及R5均為C1-4烷基，或者NR4R5形成隨意地含有第二個擇自O，N或S之雜原子環成員及N及S之氧化形式之4至7員飽和雜環型環，該雜環型環乃隨意地經一或二個C1-4烷基團及/或一或二個側氧基團所取代；且R3為D基團：其中星號代表接合至異吲哚啉環上之接合點；但排除乙酸5-乙醯氧基-4-異內基-2-〔5-(4-甲基-哌嗪-1-基甲基)-1,3-二氫-異吲哚-2-羰基〕-苯酯。
