“Genetic toxicology studies were not conducted or needed per ICH S6 guidance.”
✓ VerifiedFDA pharmacology/toxicology review, p. 7Source ↗
Carcinogenicity
Not conducted; weight-of-evidence suggests low risk, but reduced immune surveillance means increased tumor susceptibility cannot be ruled out
“Rodent carcinogenicity studies have not been conducted with siltuximab. Evidence from studies conducted with siltuximab and other IL-6 inhibitors suggest that the potential for siltuximab to cause carcinogenicity is low.”
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
Monkey EFD and ePPND (humanized analog): placental transfer, reduced globulin in dams and offspring; mouse surrogate fertility studies negative
“Siltuximab crossed the placenta and resulted in reduced globulin levels in pregnant animals and in the offspring; this may be secondary to a decreased production of immunoglobulin as expected from the pharmacology of this product.”
✓ VerifiedFDA pharmacology/toxicology review, p. 8Source ↗
Safety pharmacology
Incorporated into 3- and 6-month monkey studies (ECG, BP, respiration, CNS observations); no siltuximab-related adverse effects
“No siltuximab treatment–related adverse effects on safety pharmacology parameters were observed in the 3 and 6 months toxicology studies.”
“Genetic toxicology studies were not conducted or needed per ICH S6 guidance.”
✓ VerifiedFDA pharmacology/toxicology review, p. 7Source ↗
Genotox: in vitro mammalian
Not conducted (ICH S6)
“Genetic toxicology studies were not conducted or needed per ICH S6 guidance.”
✓ VerifiedFDA pharmacology/toxicology review, p. 7Source ↗
Genotox: in vivo
Not conducted (ICH S6)
“Genetic toxicology studies were not conducted or needed per ICH S6 guidance.”
✓ VerifiedFDA pharmacology/toxicology review, p. 7Source ↗
Carcinogenicity model
Not conducted; weight of evidence suggests low potential, but increased susceptibility to specific tumors not ruled out
“Rodent carcinogenicity studies have not been conducted with siltuximab. Evidence from studies conducted with siltuximab and other IL-6 inhibitors suggest that the potential for siltuximab to cause carcinogenicity is low.”
“Genotoxicity, carcinogenicity and dedicated safety pharmacology studies were not conducted and were not needed for this application.”
✓ VerifiedFDA pharmacology/toxicology review, p. 16Source ↗
hERG / QT
No hERG assay; monkey ECGs in 3- and 6-month studies normal apart from isolated premature complexes
“All ECGs were normal in siltuximab-dosed animals in the 3 and 6-month toxicology studies, with the exception of isolated ventricular premature complexes (VPCs) seen in 2 monkeys administered 46 mg/kg, and arterial premature complexes (APCs) seen at in 1 male administered 9.2 mg/kg.”