Therapeutic dendrimer

A dendrimer comprising:

• i) a core unit (C);
• and
• ii) building units (BU), each building unit being a lysine residue or an analogue thereof;
• wherein the core unit is covalently attached to two building units via amide linkages, each amide linkage being formed between a nitrogen atom present in the core unit and the carbon atom of an acyl group present in a building unit;
• the dendrimer being a five generation building unit dendrimer;
• wherein building units of different generations are covalently attached to one another via amide linkages formed between a nitrogen atom present in one building unit and the carbon atom of an acyl group present in another building unit;
• the dendrimer further comprising:
• iii) a plurality of first terminal groups (T1) comprising a residue of a camptothecin active covalently attached to a diacyl linker group of formula
• wherein A is a C2-C10 alkylene group which is optionally interrupted by O, S, NH, or N(Me), or in which A is a heterocycle selected from the group consisting of tetrahydrofuran, tetrahydrothiophene, pyrrolidine and N-methylpyrrolidine;
• and
• iv) a plurality of second terminal groups (T2) comprising a PEG or PEOX group;
• wherein at least one half of the outer building units have one nitrogen atom covalently attached to a first terminal group and have one nitrogen atom covalently attached to a second terminal group;
• or a pharmaceutically acceptable salt thereof.