Nerlynx: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on Sep 24, 2023.

1. How it works

• Nerlynx (neratinib) is a kinase inhibitor that may be used alone or in combination with other medicines to treat human epidermal growth factor receptor 2 (HER2) positive breast cancer.
• Nerlynx works by irreversibly binding to and inhibiting specific receptors, called HER2, HER4, and EGFR receptors, found in abnormally large numbers on the surface of cancer cells. These receptors receive signals that tell cancer to grow and spread. Nerlynx inhibits their ability to direct the activity of other cells and prevents HER2-positive breast cancer cells from growing and multiplying.
• Nerlynx belongs to the class of medicines known as tyrosine kinase inhibitors. It may also be called a small molecule targeted treatment or an irreversible pan-HER inhibitor.

2. Upsides

• May be used for the treatment of early-stage HER2-positive breast cancer after treatment with trastuzumab has already been given. May also be used in combination with capecitabine for adults with advanced or metastatic HER2-positive breast cancer who have already received two or more prior anti-HER2-based regimens.
• Usually taken as a single dose of 240mg. For early-stage Her-2 positive breast cancer, it is given once a day, every day for up to one year unless the breast cancer recurs. For advanced or metastatic breast cancer it is given every day of a 21-day cycle (with capecitabine [Xeloda] given on days 1-14 of the cycle) for as long as the cancer does not worsen and the side effects are tolerable.
• Nerlynx is not chemotherapy, it is a type of targeted treatment that works by irreversibly binding to and inhibiting specific receptors on the surface of cancer cells, unlike chemotherapy which tends to kill all rapidly dividing cells.
• Hair loss has not been reported as a side effect of Nerlynx and is not an anticipated side effect because of the targeted way that it works. If hair loss were to occur, it is probably due to other causes.
• Taken orally (by mouth).

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Diarrhea, nausea, abdominal pain, fatigue, vomiting, rash, mouth ulcers, decreased appetite, muscle spasms, dyspepsia, liver enzyme increases, nail disorders, dry skin, bloating, bleeding noses, weight loss, and urinary tract infections are the most common side effects reported occurring in more than 5% of people. Dizziness, dry mouth, fainting, increased heart rate, lightheadedness, rapid breathing, sunken eyes, thirst, unusual tiredness or weakness, and wrinkled skin may also occur caused by dehydration due to diarrhea.
• Diarrhea is a common side effect of Nerlynx (neratinib) and experienced by 95% of women in clinical trials who were not receiving anti-diarrhea medications. 93% is experienced diarrhea within the first month of treatment and the average time to the onset of diarrhea was 8 days. The risk of this side effect can be greatly reduced if loperamide (brand names include Imodium and Kaopectate 1-D) is started on the same day as Nerlynx is started, instead of just waiting to see if diarrhea develops or not. Withhold Nerlynx in patients experiencing severe or persistent diarrhea. Permanently discontinue in patients experiencing Grade 4 diarrhea or Grade ≥2 diarrhea that occurs after maximal dose reduction.
• Liver toxicity has occurred. Perform baseline liver function tests and repeat every 3 months during treatment. Discontinue Nerlynx and do not restart in patients experiencing Grade 4 liver abnormalities.
• The dosage of Nerlynx may need modification for people with severe liver disease, diarrhea, and concomitant CYP3A4 drug inhibitors or inducers.
• Do not use Nerlynx if you are pregnant. It could harm the unborn baby. If you are of childbearing potential, use effective contraception during treatment with Nerlynx and for 1 month afterward. Do not breastfeed during treatment and for 1 month after the last dose.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

• Nerlynx (neratinib) is an oral kinase inhibitor that may be used alone for early-stage HER-2-positive breast cancer or in combination with capecitabine for advanced or metastatic HER2-positive breast cancer if certain criteria are met. Diarrhea is the most common side effect, and loperamide (an antidiarrheal medication) should be started at the same time as Nerlynx.

5. Tips

• Before taking Nerlynx, tell your doctor if you have ever had liver disease, are pregnant or intend to become pregnant, or are breastfeeding.
• Nerlynx is usually taken as a dose of six 40 mg tablets (total of 240 mg) once a day, with food, although your healthcare provider may start you with a smaller dose for week one and then increase it over 2 weeks to this dose. Nerlynx is available as 40 mg tablets. Six 40 mg tablets are required to be taken for a 240 mg daily dose. Your healthcare provider may change your dose if needed.
• Take with food at the same time each day.
• Swallow the tablets whole. Do not chew, crush, or split the tablets.
• To minimize your risk of diarrhea always take loperamide exactly as your healthcare provider has told you to take it. If you have more than two bowel movements in one day, or you have diarrhea that doesn’t go away, tell your healthcare provider. Call your healthcare provider immediately if you have severe diarrhea or experience weakness, dizziness, or fever at the same time as diarrhea. If you develop severe diarrhea, fluid and electrolytes will also be needed. To best control diarrhea, you may need to follow a special diet.
• If you take an antacid medicine, take your Nerlynx dose three hours after the antacid medicine. If you take an acid reducer (H2 receptor blocker), take your Nerlynx dose at least 2 hours before or 10 hours after you take the acid reducer. You should avoid eating products that contain grapefruit during treatment with Nerlynx.
• Nerlynx can cause severe liver problems. Call your doctor at once if you have signs of liver problems: upper stomach pain, itching, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes). You will need blood tests every 3 months to check your liver function.
• If you miss a dose of Nerlynx, skip that dose and take your next dose at your regular scheduled time. If you take too much Nerlynx, call your healthcare provider right away.
• Although there is no direct interaction between alcohol and Nerlynx, you should not drink excessive quantities of alcohol while you are taking Nerlynx, because it may increase the risk of side effects such as diarrhea, dehydration, dizziness, and liver problems. It is OK to have a glass of alcohol now and then while taking Nerlynx.
• Do not use Nerlynx if you are pregnant. It could harm the unborn baby or cause birth defects. Use effective birth control to prevent pregnancy while you are using this medicine. Tell your doctor right away if you become pregnant. You should not breastfeed while you are taking this medicine.

6. Response and effectiveness

• In a phase 3 clinical trial (n= 2,840), Nerlynx reduced the risk of breast cancer recurrence by 34% at 2 years. 94.2% of all people studied who were HER2+ and took Nerlynx had no return of cancer after 2 years, compared to the 91.9% of people on placebo: a difference of 2.3%.
• Another trial reported a 42% reduction for HER2+ and HR+ breast cancer recurrence at 5 years. After 5 years, 90.8% of all people studied who were HER2+ and HR+ and took Nerlynx had no return of cancer, compared to the 85.7% of people taking placebo: a difference of 5.1%.
• There was a 59% reduction in the risk of CNS recurrence or death in people with HER2+ and HR+ breast cancer given Nerlynx. 98.4% of people given Nerlynx (n=670) did not experience a CNS recurrence, or death from any cause, compared to 95.7% of those given placebo (n=664): a benefit of 2.7%.

7. Interactions

Medicines that interact with Nerlynx may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Nerlynx. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Nerlynx include:

• antacids or stomach acid reducers such as omeprazole or famotidine
• antifungals such as fluconazole
• heart medications such as verapamil or digoxin
• hormones, such as levonorgestrel
• medicines used to treat HIV or AIDS such as ritonavir
• strong CYP3A4 inducers, such as phenobarbital, phenytoin, rifampicin, St. John's Wort, and glucocorticoids
• strong CYP3A4 inhibitors, such as clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil, goldenseal, and grapefruit.

If you also take an antacid: Wait at least 3 hours after taking the antacid before you take Nerlynx.

If you also take a stomach acid reducer: Take your Nerlynx dose 2 hours before or 10 hours after you take the other medicine (this includes cimetidine, famotidine, nizatidine, ranitidine, Axid, Pepcid, Tagamet, Zantac, and others).

You should not use certain stomach acid reducers, such as esomeprazole, lansoprazole, omeprazole, pantoprazole Nexium, Prevacid, Prilosec, Protonix, and others.

Note that this list is not all-inclusive and includes only common medications that may interact with Nerlynx. You should refer to the prescribing information for Nerlynx for a complete list of interactions.

References

• Nerlynx Prescribing Information. Updated 03/2022. https://nerlynxhcp.com/pdf/full-prescribing-information.pdf

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Nerlynx only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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