Samidorphan negative in a standard genotoxicity battery
“SAM was negative in a complete and adequate battery of genetic toxicology assays.”
✓ VerifiedFDA multi-discipline review, p. 320Source ↗
Carcinogenicity
Samidorphan: up to 95-week rat and 6-month rasH2 mouse studies, no tumors
“SAM is also non-carcinogenic as it did not induce tumors in male and female rats administered SAM for up to 95 weeks at exposures which are approximately 32 and 237 times the MRHD based on AUC, respectively and did not induce tumors in rasH2 transgenic mice administered SAM for 6-months.”
✓ VerifiedFDA multi-discipline review, p. 320Source ↗
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
Samidorphan rat EFD: reduced fetal weight, skeletal variations, slight malformation increase at maternally toxic doses >248x MRHD
“SAM administration to pregnant rats during the period of organogenesis resulted in decreased fetal weights, increased skeletal variations, and a slight increase in total malformations at doses that were maternally toxic and greater than 248 times the MRHD based on AUC.”
✓ VerifiedFDA multi-discipline review, p. 321Source ↗
Safety pharmacology
Samidorphan and RDC-9986 not significant hERG blockers; no cardiovascular or respiratory effects in dogs at 20x MRHD
“In safety pharmacology studies, SAM and metabolite RDC-9986 were not significant hERG channel blockers, and SAM did not have any significant adverse effects on cardiovascular or respiratory parameters in dogs at doses which are 20 times the maximum recommended human dose (MRHD) of 10 mg SAM based on AUC.”
✓ VerifiedFDA multi-discipline review, p. 320Source ↗
Genotox: Ames
Negative (samidorphan)
“No evidence of genotoxicity of samidorphan was found in the in vitro Ames bacterial reverse mutation test, the in vitro chromosome aberration assay in human peripheral blood lymphocytes or in the in vivo mouse bone marrow micronucleus assay.”
Chromosome aberration in human peripheral blood lymphocytes: negative (samidorphan)
“No evidence of genotoxicity of samidorphan was found in the in vitro Ames bacterial reverse mutation test, the in vitro chromosome aberration assay in human peripheral blood lymphocytes or in the in vivo mouse bone marrow micronucleus assay.”
Mouse bone marrow micronucleus: negative (samidorphan)
“No evidence of genotoxicity of samidorphan was found in the in vitro Ames bacterial reverse mutation test, the in vitro chromosome aberration assay in human peripheral blood lymphocytes or in the in vivo mouse bone marrow micronucleus assay.”
Samidorphan: rat up to 95 weeks and rasH2 transgenic mouse 6-month; no tumors (up to 32x/237x MRHD AUC in rats)
“SAM is also non-carcinogenic as it did not induce tumors in male and female rats administered SAM for up to 95 weeks at exposures which are approximately 32 and 237 times the MRHD based on AUC, respectively and did not induce tumors in rasH2 transgenic mice administered SAM for 6-months.”
✓ VerifiedFDA multi-discipline review, p. 320Source ↗
Carcinogenicity timing
Samidorphan: rat (up to 95 weeks) and 6-month rasH2 mouse completed before the marketing application
“SAM is also non-carcinogenic as it did not induce tumors in male and female rats administered SAM for up to 95 weeks at exposures which are approximately 32 and 237 times the MRHD based on AUC, respectively and did not induce tumors in rasH2 transgenic mice administered SAM for 6-months.”
✓ VerifiedFDA multi-discipline review, p. 320Source ↗
“In safety pharmacology studies, SAM and metabolite RDC-9986 were not significant hERG channel blockers (IC50 values of 28.19 and >280 µM, respectively).”
✓ VerifiedFDA multi-discipline review, p. 445Source ↗
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative