Nerlynx (chemical name: neratinib) is an irreversible pan-HER inhibitor. Nerlynx works against HER2-positive breast cancer by blocking the cancer cells’ ability to receive growth signals.

Nerlynx (chemical name: neratinib) is a type of targeted therapy called an irreversible pan-HER inhibitor used to treat HER2-positive breast cancer.

Nerlynx is used to treat early-stage HER2-positive breast cancer for an extended period of time after surgery (doctors calls this extended adjuvant therapy). You take Nerlynx within 2 years after you’ve had surgery and completed a chemotherapy regimen that included Herceptin (chemical name: trastuzumab).

Nerlynx also is used in combination with the chemotherapy medicine Xeloda (chemical name: capecitabine) to treat advanced-stage and metastatic HER2-positive breast cancer in people who have already been treated with at least two HER2 inhibitors for advanced-stage disease.

Nerlynx is a pill taken by mouth.

The recommended dose of Nerlynx is 240 mg (6 tablets) once per day with food.

When treating early-stage HER2-positive breast cancer, you take Nerlynx for 1 year.

When treating advanced-stage or metastatic HER2-positive breast cancer, you take Nerlynx with Xeloda on a 21-day cycle:

  • you take Nerlynx once a day with food for 21 days

  • you take Xeloda twice a day for 14 days, then stop taking Xeloda until the next 21-day cycle starts

For advanced-stage or metastatic HER2-positive breast cancer, you keep taking Nerlynx and Xeloda as long as you are getting benefits from the medicines and aren’t having troubling side effects.


How Nerlynx works

HER2-positive breast cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive. HER2-positive breast cancers tend to be more aggressive and harder to treat than HER2-negative breast cancers. Nerlynx is an irreversible pan-HER inhibitor. Nerlynx fights HER2-positive breast cancer by blocking the cancer cells’ ability to receive growth signals.


Is Nerlynx right for you?

There are several tests used to find out if breast cancer is HER2-positive. Two of the most common tests are:

IHC (ImmunoHistoChemistry)

The IHC test uses a chemical dye to stain the HER2 proteins. The IHC gives a score of 0 to 3+ that measures the amount of HER2 proteins on the surface of cells in a breast cancer tissue sample. If the score is 0 to 1+, it’s considered HER2-negative. If the score is 2+, it's considered borderline. A score of 3+ is considered HER2-positive.

If the IHC test results are borderline, it’s likely that a FISH test will be done on a sample of the cancer tissue to determine if the cancer is HER2-positive.

FISH (Fluorescence In Situ Hybridization)

The FISH test uses special labels that are attached to the HER2 proteins. The special labels have chemicals added to them so they change color and glow in the dark when they attach to the HER2 proteins. This test is the most accurate, but it is more expensive and takes longer to return results. This is why an IHC test is usually the first test done to see if a cancer is HER2-positive. With the FISH test, you get a score of either positive or negative (some hospitals call a negative test result “zero”).

Learn more about HER2 status.


What to expect when taking Nerlynx

If you take an antacid medicine, such as a proton pump inhibitor or an H2-receptor antagonist, you should wait 3 hours after taking the antacid to take Nerlynx. Prilosec, Prevacid, and Nexium are common proton pump inhibitors. Pepcid, Tagamet, and Zantac are common H2-receptor antagonists.

You should not take a type of medicine called a CYP3A inhibitor at the same time as Nerlynx because it increases the effects of Nerlynx. This class of medicines includes antifungal medicines such as Onmel (chemical name: itraconazole) and Biaxin (chemical name: clarithromycin), as well as antiretroviral drugs used to treat HIV such as Kaletra (chemical names: lopinavir and ritonavir).

You should not take a type of medicine called a CYP3A inducer at the same time as Nerlynx because it decreases the effects of Nerlynx. This class of medicines includes Rifamate (chemical name: rifampin), an antibiotic used to treat tuberculosis, and Carbatrol (chemical name: carbamazepine), which is used to control certain types of seizures in people with epilepsy.

You should not eat grapefruit or pomegranate or drink grapefruit juice or pomegranate juice, because they can increase the effects of Nerlynx.

Women who are pregnant or nursing or are planning to get pregnant should not take Nerlynx. Nerlynx can cause embryo death and birth defects. It’s important that you don’t get pregnant while you’re taking Nerlynx; you must use effective birth control.


Paying for Nerlynx

If your doctor prescribes Nerlynx and you have problems paying for the medicine, the Nerlynx patient support program may be able to help you. Puma Biotechnology, the company that makes Nerlynx, has created a co-pay card for Nerlynx to help people pay for out-of-pocket costs associated with Nerlynx. To be eligible, you must have commercial insurance. For more information, visit the Nerlynx co-pay card webpage.


Nerlynx side effects

Severe diarrhea soon after starting Nerlynx is a very common side effect. In the ExteNET trial, about 40% of the women treated with Nerlynx had severe diarrhea as a side effect.

The FDA approval recommends that loperamide (brand names include Imodium, Kaopectate 1-D, and Pepto Diarrhea Control) be given with Nerlynx for the first 56 days of treatment and then as needed to help manage diarrhea.

Other common side effects of Nerlynx are:

In rare cases, Nerlynx may cause serious liver problems. Tell your doctor right away if you have any of the following signs of liver problems:

  • yellowing of the skin or the whites of the eyes

  • dark or brown urine

  • feeling very tired

  • loss of appetite

  • pain on the upper right side of the abdomen

  • bleeding or bruising more easily than normal


Nerlynx (neratinib) prescribing information. Puma. Los Angeles, CA. 2018. Available at: (PDF)

— Last updated on April 7, 2022, 1:32 PM

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