Impurity or metaboliteAcceptedBeyond the letter
Major active metabolite M21 not covered by animal exposure; no safety margins for M21
Why: M21 pharmacodynamic activity similar to parent momelotinib · Pharmacology or kinetics
“Although the major active metabolite M21 is not considered qualified based on free exposure in animal species in line with the ICH M3(R2), it can be considered qualified based on pharmacodynamic activities similar to MMB.”
✓ VerifiedEMA assessment report, p. 30Source ↗ GenotoxicityAcceptedBeyond the letter
No in vitro genotoxicity studies with the major active metabolite M21
Why: M21 present at sufficient exposure in the in vivo rat micronucleus test · Pharmacology or kinetics
“No in vitro genotoxicity studies were performed with the major active metabolite M21.”
✓ VerifiedEMA assessment report, p. 31Source ↗ “Based on the TK data observed in the repeat-dose toxicity study in rats, the metabolite M21 should has been present at sufficient exposure levels to be considered as qualified.”
✓ VerifiedEMA assessment report, p. 31Source ↗ Safety marginVerdict not stated
39-week dog NOAEL below 0.6 times the MRHD (combined momelotinib + M21 AUC)
“The NOAEL based on mild testicular bilateral spermatocyte degeneration and renal epithelial vacuolation was 20 mg/kg/day in dogs (<0.6x the MRHD on an AUC basis for combined momelotinib + M21).”
✓ VerifiedFDA integrated review, p. 188Source ↗ GLPVerdict not stated
Toxicokinetic analyses in several pivotal GLP studies not GLP-compliant
Why: Method validation followed GLP principles
“For some pivotal GLP toxicology studies, toxicokinetics analysis were not performed in compliance with GLP (8283319 4-week in mice; 8336287 4-week impurities in rats ; WIL-604183 Juvenile DRF in rats ; WIL-604256 Juvenile in rats and 8283320 26-week study carcinogenicity in mice), but validation was conducted following the principles of GLP.”
✓ VerifiedEMA assessment report, p. 27Source ↗