The invention provides a compound of the formula (1 ): or a salt, solvate, N-oxide or tautomer thereof； wherein either R1 is R1a and R2 is R2a； or R1 is R1b and R2 is R2b； provided that in each case at least one of R1 and R2 is other than hydrogen； R1a and R2a are the same or different and each is selected from hydrogen, C1-4 alkyl, C2-4 alkenyl and C2-4 alkynyl wherein the C1-4 alkyl is optionally substituted by C1-2 alkoxy； R1b and R2b are the same or different and are selected from hydrogen, C(O)NR4R5, C(O)R6 and C(O)OR6 where R6 is C1-4 alkyl, R4 and R5 are both C1-4 alkyl, or NR4R5 forms 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 C1-4 alkyl groups and/or one or two oxo groups； and R3 is 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-isoindole-2-carbonyl]-phenyl ester.Jedinjenje formule (1a):ili njegova so, solvat, N-oksid ili tautomer；pri čemu ili R1 je R1a i R2 je R2a； ili R1 je R1b i R2 je R2b； uz uslov da je uvek bar jedan od R1 i R2 različit od vodonika；R1a i R2a su isti ili različiti i svaki je izabran između vodonika, C1-4 alkila, C2-4 alkenila i C2-4 alkinila, pri čemu je C1-4alkil supstituisan sa C1-2 alkoksi；R1b i R2b su isti ili razliciti i izabrani su između vodonika, C(O)NR4R5, C(O)R6 i C(O)OR6, pn čemu R6 je C1-4 alkil, R4 i R5 su oba C1-4 alkil, ili NR4R5 formira 4- do 7-člani zasićeni heterociklični prsten, koji opciono sadrži i drugi heteroatom u prstenu izabran između O, N ili S i oksidiranih oblika N i S, pri čemu je heterociklični prsten opciono supstituisan sa jednom ili dve C1-4 alkil grupe i/ili jednom ili dve okso grupe； iR3 je grupa D:pri čemu zvezdica označava tačku vezivanja za izoindolinski prsten； ali isključujući jedin
