CarcinogenicityAccepted with a conditionBeyond the letter
2-year rat carcinogenicity study of elexacaftor ongoing at approval; completed as a postmarketing requirement
Why: Unmet medical need in the proposed indication · Rare disease / unmet need
“A 2-year carcinogenicity study in rats (Study VX-445-TX-015) is ongoing and the division agreed that this study could be completed as a Post-Marketing Requirement based on the unmet medical need in the proposed indication (communication dated Jun 28, 2018).”
✓ VerifiedFDA multi-discipline review, p. 49Source ↗ “The nonclinical team recommends approval with a 2-year carcinogenicity study in rats as a post-marketing requirement.”
✓ VerifiedFDA multi-discipline review, p. 171Source ↗ DARTAcceptedBeyond the letter
Potential synergistic effects of the triple combination on fertility not investigated
Why: Rat fertility findings occur at exposures above clinical exposure · Pharmacology or kinetics
“However, potential synergistic effects on fertility were not investigated with the triple combination which is acceptable by CHMP since the observation in rat occurs at exposures above those reached in clinic.”
✓ VerifiedEMA assessment report, p. 43Source ↗ Safety marginVerdict not stated
No NOAEL for males in the rat triple-combination study: adverse body weight effects at the lowest dose
“However, the adverse body weight effects in males already at the lowest dose result in a NOAEL that cannot be determined for male animals.”
✓ VerifiedEMA assessment report, p. 43Source ↗ Efficacy modelAcceptedBeyond the letter
No in vivo efficacy model; pharmacology studied only in vitro (CF patient bronchial epithelial cells)
Why: No validated animal model of CF; all three components bind specifically to CFTR · Other reason
“As there is no validated animal model for CF that fully mimics the human multi organ affected disease and all three components bind specifically to CFTR, the use of in vitro systems to study the pharmacology of elexacaftor only or in combination with tezacaftor and ivacaftor can be accepted.”
✓ VerifiedEMA assessment report, p. 49Source ↗