Neratinib (Nerlynx) is a targeted therapy for people with stages I to IIIc HER2-positive breast cancer who have finished treatment with trastuzumab (Herceptin). It is the first medicine for people with HER2-positive breast cancer that is approved as extended therapy, meaning it is given after primary treatment ends, to lower the risk of cancer coming back.
Neratinib is a tyrosine kinase inhibitor or TKI. Certain proteins, called tyrosine kinases, tell breast cancer cells to multiply. Neratinib blocks these proteins from working to help keep cancer from growing.
Neratinib is taken as a pill. The recommended dose is six tablets taken at the same time, once per day, for 1 year. It should be taken with food at about the same time every day.
If you take antacids (Tums, Alka-Seltzer, Pepto-Bismol, Milk of Magnesia, for example), do not take any for 3 hours before or 3 hours after taking neratinib. Do not eat grapefruit or foods with grapefruit in them, or drink grapefruit juice while taking neratinib. Eating or drinking grapefruit and its juice can make neratinib build up in your blood, leading to worse side effects.
Always tell your doctor about any other medicines or supplements you’re taking, to make sure they won’t impact how well neratinib works.
Your doctor will likely recommend loperamide (Imodium or its generics) when you start treatment to control the diarrhea. Talk with your doctor about when to take loperamide. He or she will give you a specific schedule to follow.
Other common side effects are
- stomach pain
- mouth sores
- loss of appetite
- weight loss
- nose bleeds
- nail problems or changes
- muscle spasms
Neratinib may harm a fetus, so use safe birth control while taking it to prevent pregnancy. If you’re already pregnant do not start taking neratinib, and talk to your doctor about your treatment options.
Do not breastfeed while taking neratinib, and wait at least 1 month after your last dose of neratinib to start breastfeeding.