Minipig/pig studies to 6 months showed no immune response to rhCNTF or cells; mild to moderate ocular inflammation
“Two preclinical studies in minipigs or pigs implanted with NT-501-6A.02 device for up to 6 months showed no immune response to rhCNTF or cell producing the protein.”
✓ VerifiedFDA pharmacology/toxicology review, p. 49Source ↗
Biodistribution & persistence
No systemic rhCNTF exposure after ITV implant (minipig to 6 months, rabbit to 9 months); implants delivered about 7-9 ng/day
“In rabbits, NT-501 implants established CNTF levels averaging about 7-9 ng/day for up to 9 months.”
✓ VerifiedFDA pharmacology/toxicology review, p. 2Source ↗
Modality-specific risk
Local ocular toxicity from capsule/rhCNTF dose (cone effects at high output), device failure with cell release, systemic CNTF exposure
“a dose-response to rhCNTF was present, with eyes implanted with empty capsules and capsules with a low CNTF output cell line exhibiting less intense changes than eyes implanted with NT-501.”
✓ VerifiedFDA pharmacology/toxicology review, p. 2Source ↗
Anti-drug antibodies: animals
No immune response to rhCNTF or cells in minipigs/pigs implanted up to 6 months
“Two preclinical studies in minipigs or pigs implanted with NT-501-6A.02 device for up to 6 months showed no immune response to rhCNTF or cell producing the protein.”
✓ VerifiedFDA pharmacology/toxicology review, p. 49Source ↗
Anti-drug antibodies: patients
Anti-rhCNTF antibodies in 1 of 31 patients (3%); anti-DHFR antibodies in 1 patient (3%)
“one out of 31 patients (3%) tested positive for serum antibodies against the ENCELTO secreted product protein rhCNTF and one patient (3%) tested positive to serum non-secreted intracellular protein DHFR.”