STAT3 and B-cell chronic lymphocytic leukemia: While OPB-111077 is probably the most promising OPB candidate by far, pyrimethamine and TTI-101 are two other STAT3 SH2 domain inhibitors currently undergoing early phase clinical trials in relapsed chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL) (NCT01066663) and other advanced cancers including HCC (NCT03195699) respectively (Table 3).