TX-2552 is an orally effective inhibitor of tyrosyl-DNA phosphodiesterase 1 (TDP1), with an IC50 value of 0.62 μM. It enhances the cleavage activity of topotecan in mouse bone marrow cells and amplifies the antitumor effects of topotecan in Krebs-2 ascites tumor-bearing mice.

TX-2552 administered at doses ranging from 20-160 mg/kg via oral gavage enhanced the clastogenic effects of topotecan in a chromosomal aberration mouse model. When given at 20-120 mg/kg through intraperitoneal injection daily for 18 days, TX-2552 augmented the antitumor efficacy of topotecan in Krebs-2 ascites tumor-bearing mice, decreasing tumor volume and prolonging lifespan. In the chromosomal aberration experiment, the increase in aberrant metaphases induced by topotecan was 2.1-2.6 fold. Notably, this response was witnessed in F1 hybrid mice (CBA×C57BL/6), where topotecan was administered intraperitoneally at single doses of 0.25, 0.5, and 1 mg/kg, showing a dose-dependent effect.