Genotoxic: Ames negative; positive in CHO chromosome aberration, mouse lymphoma and rat micronucleus assays
“Tirbanibulin was negative in an in vitro bacterial reverse mutation (Ames) assay. Tirbanibulin was positive in an in vitro chromosomal aberration assay with Chinese hamster ovary (CHO) cells, an in vitro mouse lymphoma assay with L5178/TK +/- cells, and an in vivo micronucleus assay in rats.”
Not conducted (short-term use, no chronic exposure)
“Not applicable, as the proposed use does not involve chronic exposure.”
✓ VerifiedFDA multi-discipline review, p. 46Source ↗
Instead of carcinogenicity
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Instead of genotoxicity
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
DRG histopathology
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Reproductive & developmental
Rat EFD: fetal deaths and malformations at ≥1.25 mg/kg/day
“Tirbanibulin induced fetal deaths and external, visceral, and skeletal malformations when administered orally to pregnant rats during the period of organogenesis at doses greater than or equal to 1.25 mg/kg/day,”
Irwin and hERG negative; no CV effects in dogs at clinically relevant exposure; no ECG effects in 4-week dog
“The Irwin and hERG assay were negative. No cardiovascular effects were observed in dogs following intravenous dosing at clinically relevant levels of systemic exposure.”
✓ VerifiedFDA multi-discipline review, p. 33Source ↗
Genotox: Ames
Negative
“Tirbanibulin was negative in a bacterial reverse mutation (Ames) assay”
✓ VerifiedFDA multi-discipline review, p. 34Source ↗
Genotox: in vitro mammalian
Positive: CHO chromosomal aberration and mouse lymphoma (L5178Y TK+/-) assays
“Tirbanibulin was positive in an in vitro chromosomal aberration assay with Chinese hamster ovary (CHO) cells, an in vitro mouse lymphoma assay with L5178/TK +/- cells, and an in vivo micronucleus assay in rats.”
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative