GenotoxicityAccepted with a conditionBeyond the letter
Positive genotoxicity (clastogenic in vitro and in vivo, weakly mutagenic in mouse lymphoma) accepted for a topical product
Why: Short-term use only; marketed actinic keratosis alternative fluorouracil is also a genetic toxicant; addressed through labeling · Class precedent · Other reason
“Although tirbanibulin is a genetic toxicant, this matter may be appropriately addressed through labeling. The product is intended for short-term use only, which partially assuages concerns about genotoxicity.”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗ “Also, it should be considered that a currently marketed product that is labeled for topical treatment of actinic keratoses, Efudex (a clinical alternative) contains fluorouracil, which is a genetic toxicant. No nonclinical post-marketing requirements are necessary.”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗ CarcinogenicityAccepted
No carcinogenicity studies
Why: Proposed use does not involve chronic exposure · Within the guideline
“Not applicable, as the proposed use does not involve chronic exposure.”
✓ VerifiedFDA multi-discipline review, p. 46Source ↗