When administered as Irinotecan (CPT-11, 5 mg/kg) via intratumoral injection daily for five consecutive days over two weeks in rats, significant tumor growth inhibition is observed. This inhibitory effect is also noted with continuous intraperitoneal infusion using an osmotic minipump in mice. However, a dosage of 10 mg/kg by intraperitoneal injection does not affect tumor growth^[1].

Additionally, Irinotecan (CPT-11, 100-300 mg/kg, i.p.) significantly diminishes the growth of HT-29 xenografts in athymic female mice by the 21st day. Combination therapies of Irinotecan (125 mg/kg) with TSP-1 (10 mg/kg per day) or Irinotecan (150 mg/kg) with TSP-1 (20 mg/kg per day) show nearly identical efficacy, reducing tumor growth by 84% and 89%, respectively. These combinations prove more effective than Irinotecan alone at doses of 250 and 300 mg/kg^[3].

Irinotecan effectively halts the growth of LoVo and HT-29 cells, achieving IC50 values of 15.8 ± 5.1 and 5.17 ± 1.4 μM, respectively. In these cell lines, Irinotecan also prompts the formation of a comparable level of cleavable complexes^[2].

Moreover, Irinotecan hinders the proliferation of human umbilical vein endothelial cells (HUVEC), evidenced by an IC50 of 1.3 μM^[3].