The preclinical study employed in vitro models to assess the cytotoxicity of PEG-SN38, while in vivo therapeutic efficacy was evaluated in terms of survival, antitumor and antiangiogenic activity in three different animal models. The animal models were designed to closely reflect the primary, metastatic, and advanced stages of neuroblastoma in pediatric patients.

The data show that PEG-SN38 was 100-fold more potent than CPT-11 in vitro, as measured by the induction of cancer-cell death as well as through anti-angiogenesis and drug resistance indicators. In vivo, treatment with PEG-SN38 resulted in no detectable tumor at the end of the studies, whereas only minor therapeutic effect was observed with CPT-11. PEG-SN38 also blocked tumor relapse following treatment with other drugs commonly used to treat neuroblastoma. In tumors that were resistant to these drugs, use of PEG-SN38 resulted in 100 percent curability. These data further substantiate the superior preclinical profile of PEG-SN38 compared with CPT-11 that has been previously observed in models of human tumors (see Sapra et al. 2008. Clin Cancer Res 14: 1888-1896 and Sapra et al., 2009. Hematologica 94: 1456-1459).

A copy of the publication is available through the website of the American Association of Cancer Research website at clincancerres.aacrjournals.

SOURCE Enzon Pharmaceuticals, Inc.