Lapatinib

The Basics

What is Lapatinib?

Used to treat HER2-positive breast cancer.

Brand names for Lapatinib

Tykerb

How Lapatinib is classified

Antineoplastic Agents, Enzyme Inhibitors, Protein Kinase Inhibitors, Signal Transduction Inhibitors, Tyrosine Kinase Inhibitors

Lapatinib During Pregnancy

Lapatinib pregnancy category

Category N/ANote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Lapatinib while pregnant

Based on findings in animal studies and its mechanism of action, TYKERB can cause fetal harm when administered to a pregnant woman. There are no available human data to inform of the drug associated risks. In an animal reproduction study, administration of lapatinib to pregnant rats during organogenesis and through lactation led to death of offspring within the first 4 days after birth at maternal exposures that were ‚â• 3.3 times the human clinical exposure based on AUC following 1250 mg dose of lapatinib plus capecitabine. When administered to pregnant animals during the period of organogenesis, lapatinib caused fetal anomalies (rats) or abortions (rabbits) at maternally toxic doses . Advise pregnant women and females of reproductive potential of the potential risk to the fetus. The background risk of major birth defects and miscarriage for the indicated population is unknown; however, in the U.S. general population, the estimated background risk of major birth defects is 2%-4% and of miscarriage is 15%-20% of clinically recognized pregnancies. Data Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of lapatinib at 30, 60, and 120 mg/kg/day during the period of organogenesis. Minor anomalies (left-sided umbilical artery, cervical rib, and precocious ossification) occurred in rats at the maternally toxic dose of 120 mg/kg/day (approximately 6.4 times the human clinical exposure based on AUC following 1,250 mg dose of lapatinib plus capecitabine). In rabbits, lapatinib was associated with maternal toxicity at 60 and 120 mg/kg/day (approximately 0.07 and 0.2 times the human clinical exposure, respectively, based on AUC following 1,250 mg dose of lapatinib plus capecitabine) and abortions at 120 mg/kg/day. Maternal toxicity was associated with decreased fetal body weights and minor skeletal variations. In a pre- and post-natal development study, rats were given oral doses of 20, 60, and 120 mg/kg/day during gestation through lactation up to weaning. In rats, doses of 60 and 120 mg/kg/day (approximately 3.3 and 6.4 times the human clinical exposure, respectively, based on AUC following 1,250 mg dose of lapatinib plus capecitabine) led to decrease in F1 postnatal survival (91% and 34% of the pups died by the fourth day after birth, at 60 and 120 mg/kg/day, respectively).

Taking Lapatinib While Breastfeeding

What are recommendations for lactation if you're taking Lapatinib?

No information is available on the clinical use of lapatinib during breastfeeding. Because lapatinib is more than 99% bound to plasma proteins, the amount in milk is likely to be low. However, its half-life is about 24 hours and it might accumulate in the infant. It is also given in combination with capecitabine, which may increase the risk to the infant. The manufacturer recommends that breastfeeding be discontinued during lapatinib therapy and for 1 week after the last dose.

Maternal / infant drug levels

No information is available on the clinical use of lapatinib during breastfeeding. Because lapatinib is more than 99% bound to plasma proteins, the amount in milk is likely to be low. However, its half-life is about 24 hours and it might accumulate in the infant. It is also given in combination with capecitabine, which may increase the risk to the infant. The manufacturer recommends that breastfeeding be discontinued during lapatinib therapy and for 1 week after the last dose.

Possible effects of Lapatinib on milk supply

Relevant published information was not found as of the revision date.

Possible alternatives to Lapatinib

None listed