No effects on TDAR or immunophenotyping in juvenile rat; lymphoid necrosis in spleen/thymus at high dose in mouse
“No drug-related effects were observed on TDAR, immunophenotyping, physical development, neurobehavioral development, or on the male reproductive system.”
✓ VerifiedFDA pharmacology/toxicology review, p. 18Source ↗
Biodistribution & persistence
Rapid, widespread distribution; highest in kidney, low in brain; ~60% urinary excretion; only kidney retained at 56 days
“Widespread tissue distribution was detected by QWBA, with highest peak levels in kidney (165000 ng-eq/g). At 56 days postdose, radioactivity was detected only in kidney and urine.”
✓ VerifiedFDA pharmacology/toxicology review, p. 13Source ↗
Modality-specific risk
Renal tubular toxicity (PMO kidney accumulation); also lateral ventricle dilatation (mdx mouse) and juvenile bone density loss
“Regarding toxicity, the primary toxicities observed with eteplirsen were renal tubule degeneration/necrosis in all species tested (mdx mouse, juvenile rat, cynomolgus monkey), dilatation of lateral ventricles in mdx mouse, and decreases in bone mineral content and density in juvenile rat.”
✓ VerifiedFDA pharmacology/toxicology review, p. 20Source ↗
Anti-drug antibodies: animals
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.
Anti-drug antibodies: patients
Anti-eteplirsen IgG in 1/129 patients (0.78%); IgE in 3/21 (14.3%)
“With administration of 30 mg/kg/week of EXONDYS 51, during the 192-week treatment duration in three clinical studies, 1 out of 129 patients (0.78%) was positive for anti-eteplirsen IgG and 3 out of 21 patients with non-missing samples (14.3%) were positive for anti-eteplirsen IgE.”
Main pharmacology-related risk is increased susceptibility to infections (C5 inhibition); no complement activation by the aptamer in monkeys; panuveitis with Lucentis combination