NERLYNX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NERLYNX (NERLYNX).
Neratinib is an irreversible pan-ErbB receptor tyrosine kinase inhibitor that inhibits EGFR, HER2, and HER4, leading to reduced downstream signaling and cell proliferation.
| Metabolism | Primarily metabolized by CYP3A4; also a substrate of P-glycoprotein (P-gp). |
| Excretion | Primarily hepatic metabolism; 97% of dose recovered in feces (including unchanged drug and metabolites), <1% in urine as unchanged drug. Biliary excretion is a major route. |
| Half-life | Terminal half-life approximately 7–17 days (mean ~9 days) after a 240 mg daily dose, supporting once-daily dosing. Steady state reached by ~4–6 weeks. |
| Protein binding | Approximately 99% bound to plasma proteins, primarily albumin and α1-acid glycoprotein. |
| Volume of Distribution | Mean Vd/F ~ 2,340 L (range 1,190–8,510 L) after oral administration, indicating extensive distribution into tissues (Vd > total body water). Not routinely expressed per kg. |
| Bioavailability | Oral bioavailability is low (~30%) due to extensive first-pass metabolism. Absolute bioavailability not established in humans; relative bioavailability compared to oral solution is 100%. |
| Onset of Action | Not applicable for oral tablet; clinical effect (tumor response) typically assessed after ≥8 weeks of continuous dosing. |
| Duration of Action | Prolonged due to long half-life; drug remains at therapeutic levels for several weeks after discontinuation. Continued inhibition of HER2 signaling persists while drug is present. |
NERLYNX (neratinib) 240 mg (6 tablets of 40 mg) orally once daily with food for a total duration of 1 year.
| Dosage form | TABLET |
| Renal impairment | For severe renal impairment (CrCl 30-89 mL/min), no dose adjustment is required. For end-stage renal disease (CrCl <30 mL/min), no data available; use with caution. |
| Liver impairment | For mild hepatic impairment (Child-Pugh A), no dose adjustment. For moderate (Child-Pugh B), reduce dose to 120 mg (3 tablets) once daily. For severe (Child-Pugh C), reduce dose to 80 mg (2 tablets) once daily. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established; no recommended dosing. |
| Geriatric use | No specific dose adjustment based on age alone; monitor renal and hepatic function due to potential age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NERLYNX (NERLYNX).
| Breastfeeding | No data are available on the presence of neratinib in human milk, its effects on the breastfed infant, or its effects on milk production. Due to the potential for serious adverse reactions in nursing infants, advise lactating women not to breastfeed during treatment with NERLYNX and for at least 1 month after the last dose. M/P ratio: Not determined. |
| Teratogenic Risk | Based on its mechanism of action as a tyrosine kinase inhibitor and animal studies, NERLYNX (neratinib) is expected to cause fetal harm when administered to pregnant women. In animal reproduction studies, neratinib was embryotoxic and fetotoxic at maternal exposures below the recommended human dose. There are no adequate and well-controlled studies in pregnant women. Use during pregnancy should be avoided; if used, the patient should be apprised of the potential hazard to the fetus. First trimester: Highest risk of major congenital malformations. Second and third trimesters: Risk of fetal growth restriction, oligohydramnios, and potential fetal/neonatal toxicity. |
■ FDA Black Box Warning
Nerlynx can cause severe and life-threatening diarrhea. Monitor and manage diarrhea aggressively. If diarrhea is not adequately managed, interrupt or dose reduce Nerlynx.
| Serious Effects |
None known.
| Precautions | ["Diarrhea: Severe and life-threatening; monitor and manage aggressively.","Hepatotoxicity: Elevated transaminases and bilirubin; monitor liver function tests.","Embryo-fetal toxicity: Can cause fetal harm; advise females of reproductive potential of effective contraception."] |
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| Fetal Monitoring | Monitor maternal liver function tests (ALT, AST, bilirubin) monthly during treatment due to risk of hepatotoxicity. Monitor for diarrhea and manage aggressively with antidiarrheals and hydration. Fetal monitoring: Perform ultrasound assessment of fetal growth and amniotic fluid volume if pregnancy occurs during treatment. Monitor for signs of fetal distress if used inadvertently. |
| Fertility Effects | Based on animal studies, NERLYNX may impair female fertility. In female rats, neratinib caused prolonged estrus cycles and reduced fertility at doses below the clinical exposure. Reversibility of effects was not assessed. The effect on male fertility is unknown. Human data on fertility are lacking. |