DARTAccepted with a conditionBeyond the letter
No fertility, embryo-fetal or pre/postnatal development studies despite ovary and estrus-cycle findings in rats
Why: Short duration of clinical use and patient needs; CDK4/6 inhibitor class labels already describe reproductive toxicity · Class precedent · Serious disease
“No developmental or reproductive toxicity (DART) studies were conducted, consistent with the short duration of clinical use and therapeutic needs of the patient population, but there was no additional data to inform potential endocrine/reproductive toxicity.”
✓ VerifiedFDA pharmacology/toxicology review, p. 9Source ↗ “Labels for other US-listed CDK4/6 inhibitors show endocrine/reproductive toxicity in the class and potential risks can be described in the label for trilaciclib.”
✓ VerifiedFDA pharmacology/toxicology review, p. 9Source ↗ CarcinogenicityAcceptedBeyond the letter
No carcinogenicity assessment in animals
Why: Patients already receive chemotherapy for existing small cell lung cancer, so little to gain · Serious disease
“Carcinogenic potential of trilaciclib has not been assessed in animals.”
✓ VerifiedFDA pharmacology/toxicology review, p. 70Source ↗ “Importantly, trilaciclib clinical dosing is in patients who are receiving chemotherapy to target existing small cell lung cancer so there was little to be gained”
✓ VerifiedFDA pharmacology/toxicology review, p. 70Source ↗ GenotoxicityAcceptedBeyond the letter
No in vivo genotoxicity assay; in vitro micronucleus increase in human lymphocytes
Why: Patients with SCLC are already treated with genotoxic chemotherapy, so further genotoxicity testing is not needed · Serious disease
“Genetic toxicity was not assessed in any in vivo assay (e.g., rat liver micronucleus formation in vivo to assess clastogenic potential).”
✓ VerifiedFDA pharmacology/toxicology review, p. 65Source ↗ “The proposed indicated use in SCLC patients being treated with genotoxic chemotherapeutic agents also obviates a need for any further genotoxicity of trilaciclib or trilaciclib metabolites (e.g., M8) for the proposed use.”
✓ VerifiedFDA pharmacology/toxicology review, p. 65Source ↗ Impurity or metaboliteAccepted with a condition
Major human metabolite M8 not formed in rat or dog and not qualified (genotoxicity unknown)
Why: M8 pharmacologically inactive; ICH S9 for advanced cancer; sponsor to submit ongoing M8 investigations · Within the guideline · Pharmacology or kinetics · Serious disease
“Given that M8 is not pharmacologically active, and consistent with ICH S9 guidance for anticancer pharmaceuticals, further qualification of M8 is not recommended for patients with advanced cancer.”
✓ VerifiedFDA pharmacology/toxicology review, p. 10Source ↗ “The sponsor agreed to update the NDA with results from ongoing nonclinical investigations related to the major human metabolite, M8.”
✓ VerifiedFDA pharmacology/toxicology review, p. 11Source ↗ Safety marginVerdict not stated
Pivotal IV dog study NOAEL 5 mg/kg at 0.5 times the MRHD
“NOAEL = 5 mg/kg (0.5X MRHD) [LOAEL = 15 mg/kg (1X MRHD; consistent with exaggerated pharmacologic effect)]”
✓ VerifiedFDA pharmacology/toxicology review, p. 58Source ↗