Negative in Ames, in vitro chromosome aberration (CHO) and in vivo mouse micronucleus assays
“pacritinib was not mutagenic in a bacterial mutagenicity assay (Ames test) or clastogenic in in vitro chromosomal aberration assay (Chinese hamster ovary cells) or in vivo in a micronucleus test in mice”
2-year rat and 26-week Tg(HRAS) mouse: not carcinogenic
“Pacritinib was not carcinogenic in either a 2-year rat study or during a 26-week hemizygous Tg(HRAS) transgenic mouse study, demonstrating low carcinogenic potential secondary to inhibition of JAK2/FLT3 activity.”
Mouse EFD: post-implantation loss, lower fetal weight and cleft palate at maternally toxic high dose
“The NOAEL for embryo-fetal development was also considered the MD based on higher post-implantation loss, lower mean fetal body weights, and altered external fetal morphology (cleft palate) observed in the presence of maternal toxicity at the HD.”
“Pacritinib inhibited human ether-à-go-go-related gene (hERG) potassium channel with a mean IC50 of 3μM, substantially higher than free plasma concentrations at clinical exposure”
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative