Starting-dose rationale not stated; FDA capped clinical IT dose at 25 mg (~1/10 mouse/monkey NOAEL), later 50 mg Q12W
“The FDA placed protocol ION373-CS1 on hold for IT doses of ION373 exceeding 25 mg, which is approximately 1/10th the NOAELs in mouse and monkey”
✓ VerifiedFDA integrated review, p. 133Source ↗