Negative in Ames, in vitro chromosome aberration and in vivo rat bone marrow micronucleus assays
“In genetic toxicology studies, elacestrant was not mutagenic in an in vitro bacterial reverse mutation (Ames) assay or, clastogenic in either in vitro chromosome aberration assays or an in vivo rat bone marrow micronucleus assay.”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
Carcinogenicity
Not conducted (ICH S9); benign granulosa cell tumors in female rats in 26-week study at ≥25 mg/kg/day
“Carcinogenicity studies were not conducted with elacestrant in accordance with ICH S9 guidance; however, of note, in the rat 26-week repeat dose toxicology study B-granulosa cell tumor was observed at ≥25 mg/kg/day”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
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 (GD 6–17): embryolethal and teratogenic at ≤30 mg/kg/day
“Elacestrant was embryo lethal and teratogenic when administered to pregnant rats at ≤30 mg/kg via daily oral gavage during the period of organogenesis on gestational days 6 through 17 followed by cesarean section on gestational day 21.”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
Safety pharmacology
hERG IC50 0.41 µM (~87% block at 1 µM); complete block of rabbit Purkinje fiber action potential at 10 µM
“Elacestrant blocked the hERG channel up to approximately 87% at 1 µM (IC50= 0.41 µM) and led to a complete block of the cardiac action potential of rabbit Purkinje fibers at 10 µM.”
✓ VerifiedFDA multi-discipline review, p. 40Source ↗
Genotox: Ames
Negative
“In genetic toxicology studies, elacestrant was not mutagenic in an in vitro bacterial reverse mutation (Ames) assay or, clastogenic in either in vitro chromosome aberration assays or an in vivo rat bone marrow micronucleus assay.”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
Genotox: in vitro mammalian
Negative: chromosome aberration in human lymphocytes
“Elacestrant was not mutagenic in bacterial reverse mutation (Ames) assays (Study 7801-100 and Study 15RAD251) and did not induce chromosomal aberrations in human lymphocytes (Study 7801-101 and Study 15RAD252).”
Not conducted (ICH S9); granulosa cell tumors seen in 26-week rat study
“Carcinogenicity studies were not conducted with elacestrant in accordance with ICH S9 guidance; however, of note, in the rat 26-week repeat dose toxicology study B-granulosa cell tumor was observed at ≥25 mg/kg/day”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
Carcinogenicity timing
Not required; carcinogenicity studies not conducted per ICH S9 (advanced cancer)
“Carcinogenicity studies were not conducted with elacestrant in accordance with ICH S9 guidance”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗
hERG / QT
hERG IC50 187 ng/mL, ~69-fold above unbound monkey concentration at a dose without QT effects
“A comparison of in vitro hERG inhibition (IC50 187 ng/mL) and estimated unbound elacestrant concentration of 2.7 ng/mL in monkey plasma at 50 mg/kg (a dose that was shown to be devoid of any QT interval effects) showed an approximately 69-fold safety margin.”
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative