Ester derivatives of rhein and their therapeutic use

A pharmaceutical composition for use in therapy, comprising a pharmaceutically acceptable diluent or carrier and a compound of general formula (I):

• wherein X1 is H or COR1 and X2 is H or COR2 but X1 and X2 are not both H;
• R1 and R2 are the same or different and are each C1-4 alkyl substituted with R or a four to seven-membered ring which can be optionally substituted with R8 and can contain one or more additional heteroatoms selected from O, S(O)n and NR9;
• R3 is F, CF3, OR4, NR5R6 or S(O)nR7;
• R4, R5, and R6 are the same or different and are each H or C1-4 alkyl optionally substituted with R3, or NR5R6 is a C4-6 heterocycloalkyl ring containing one or more heteroatoms selected from O, NR8 and S(O)n;
• each n is 0-2;
• R7 is C1-4alkyl;
• R8 is as defined for R3 or C1-4 alkyl optionally substituted with R3 or halogen;
• and
• R9 is H or C1-4alkyl;
• or a salt, solvate or hydrate thereof.

A method for the treatment or prevention of a condition associated with T-cell proliferation or that is mediated by pro-inflammatory cytokines wherein said method comprises administering, to a patient in need of such treatment, a compound of general formula (I):

• wherein X1 is H or COR1 and X2 is H or COR2 but X1 and X2 are not both H;
• R1 and R2 are the same or different and are each C1-4 alkyl substituted with R3, or a four to seven-membered ring which can be optionally substituted with R8 and can contain one or more additional heteroatoms selected from O, S(O)n and NR9;
• R3 is F, CF3, OR4, NR5R6 or S(O)nR7;
• R5, and R6 are the same or different and are each H or C1-4 alkyl optionally substituted with R3 or NR5R6 is a C4-6 heterocycloalkyl ring containing one or more heteroatoms selected from O, NR8 and S(O)n;
• each n is 0-2;
• R7 is C1-4 alkyl;
• R8 is as defined for R3 or C1-4 alkyl optionally substituted with R3 or halogen;
• and
• R9 is H or C1-4 alkyl;
• or a salt, solvate or hydrate thereof.