A compound selected from compounds of the following formula, and pharmaceutically acceptable salts and solvates thereof: wherein: -RA4 is independently -QA4N or -O-QA4O； and -RB6 is -H or -QB6； and wherein: -QA4N is independently -QA4N1 or -QA4N2； -QA4N1 is independently -NHRQN1 or -NRQN1 2； -QA4N2 is -NRQN2RQN3； each -RQN1 is independently: -RI1, -RI4, -RI6, -RI7, -RI8, -LI-RI4, -LI-RI6, -LI-RI7 or -LI-RI8； wherein: each -RI1 is saturated aliphatic C1-6 alkyl； each -RI4 is saturated C3-6 cycloalkyl； each -RI6 is non-aromatic C3-8 heterocyclyl； each -RI7 is phenyl； each -RI8 is C5-6 heteroaryl； each -LI- is saturated aliphatic C1-3 alkylene； and wherein: each C1-6 alkyl, C3-6 cycloalkyl, non-aromatic C3-8 heterocyclyl, phenyl, C5-6 heteroaryl, and C1-3 alkylene is optionally substituted with one or more -RI9 substituents, wherein each -RI9 is independently: -RL1, -OH, -ORL1, -NH2, -NHRL1, -NRL1 2, -NRL2RL3, -C (>； = O) NH2, -C (>； = O) NHRL1, -C (>； = O) NRL1 -C (>； = O) NRL2RL3； wherein: each -NRL2RL3 is independently pyrrolidino, piperidino, piperazino or morpholino, and is optionally substituted with one or more groups selected from C1-3 alkyl and -CF3； each -RL1 is independently: -RZ1, -RZ7 or -LZ-RZ7； wherein: each -RZ1 is saturated aliphatic C1-6 alkyl； each -RZ7 is phenyl； each -LZ- is saturated aliphatic C1-3 alkylene； and wherein: each C1-6 alkyl, phenyl and C1-3 alkylene is optionally substituted with one or more -RZ9 substituents, wherein each -RZ9 is independently: -F, -Cl, -Br, -I, -RZZ1, -CF3, -OCF3, -OH, -LZZ-OH, -ORZZ1, -LZZ-ORZZ1 -NH2, -NHRZZ1, -NRZZ1 2, -NRZZ2RZZ3, -LZZ-NH2, -LZZ-NHRZZ1, -LZZ-NRZZ1 2, -LZZ-NRZZ2RZZ3, -C (>； = O) OH, -C (>； = O) ORZZ1, -C (>； = O) NH2, -C (>； = O) NHRZZ1, -C (>； = O) NRZZ1 - C (>； = O) NRZZ2RZZ3； wherein: each -RZZ1 is independently saturated aliphatic C1-4alkyl, phenyl, or benzyl； each -LZZ- is saturated aliphatic C1-5 alkylene； and each -NRZZ2RZZ3 is independently pyrrolidino, piperidino, piper
