CarcinogenicityAccepted with a conditionBeyond the letter
No carcinogenicity studies before approval; rat and mouse carcinogenicity studies deferred to postmarketing requirements
Why: High unmet need in WHIM syndrome · Rare disease / unmet need
“Carcinogenicity studies with mavorixafor have not been conducted. There was a prior agreement with the Applicant regarding the need for postmarketing requirement (PMR) studies to assess the carcinogenicity potential of mavorixafor.”
✓ VerifiedFDA integrated review, p. 155Source ↗ “There was prior agreement with the Applicant for postmarketing requirement studies to assess the carcinogenicity potential given the high unmet need for WHIM syndrome.”
✓ VerifiedFDA integrated review, p. 73Source ↗ Study lengthVerdict not stated
No chronic rat study with the marketed free base; chronic rat data only from a 26-week study of the PHB salt form
“As no chronic rat toxicity studies were conducted with the free base of mavorixafor, the 26-weeks rat study conducted with the PHB salt form of mavorixafor, referred to as AMD11070PHB, provided only supportive data for the chronic toxicity of mavorixafor in rats.”
✓ VerifiedEMA assessment report, p. 27Source ↗ DARTAcceptedBeyond the letter
No fertility, embryo-fetal or pre/postnatal development studies; literature weight-of-evidence (CXCR4/SDF-1 knockout mice) instead
Why: Human-relevant exposures hard to reach in animals; CXCR4/SDF-1 knockout mice already show developmental toxicity · Weight of evidence · Pharmacology or kinetics
“No dedicated fertility and early embryonic development, definitive embryo-fetal development, or pre- and post-natal development toxicity studies were conducted with mavorixafor.”
✓ VerifiedFDA integrated review, p. 156Source ↗ “However, given the difficulties to perform animal reproduction toxicity studies with human relevant exposure and based on the results from CXCR4/SDF-1 knock out mice which showed high peri-postnatal lethality and adverse effects on developmental, this was acceptable to the CHMP.”
✓ VerifiedEMA assessment report, p. 53Source ↗ Safety marginVerdict not stated
No exposure margin at the NOAELs in most pivotal rat and dog studies
“The CHMP concluded that, for the most parts, there were no margins from the NOAELs to clinical exposure.”
✓ VerifiedEMA assessment report, p. 54Source ↗ Juvenile toxAcceptedBeyond the letter
No definitive juvenile toxicity study in rats because of poor tolerance in juvenile rats
Why: Poor tolerance in juvenile rats at low exposures · Other reason
“It was agreed that a definitive juvenile toxicity study in rats is not feasible due to poor tolerance of mavorixafor at low exposures in juvenile rats.”
✓ VerifiedEMA assessment report, p. 53Source ↗