What is HER2+ advanced stomach cancer?

What is HER2? HER2 is a protein that tells cells to grow. In HER2+ stomach cancer, the cancer cells have too much HER2, which leads to cancer growth

These cells grow
and divide faster
than healthy cells,
causing tumors to form

In advanced
stomach cancer,
the cancer has started to spread to areas near the stomach or to other parts of the body

What is ENHERTU?

ENHERTU is a prescription medicine used to treat adults who have:

  • Stomach cancer called gastric or gastroesophageal junction (GEJ) adenocarcinoma that is HER2-positive and has spread to areas near your stomach (locally advanced) or that has spread to other parts of your body (metastatic), and who have received a prior trastuzumab-based regimen.

It is not known if ENHERTU is safe and effective in children.

How was ENHERTU studied?

ENHERTU was studied compared to commonly used chemotherapy (doctors choose between irinotecan or paclitaxel) in 188 adults with HER2+ stomach cancer that had spread beyond the stomach.

How is ENHERTU thought to work?

As a targeted treatment called an antibody-drug conjugate (ADC), ENHERTU is designed to work differently than traditional chemotherapies.

ENHERTU is made up of an antibody with the chemotherapy attached
The antibody part of ENHERTU targets and attaches to HER2 on the cancer cell
ENHERTU enters the cancer cell and the chemotherapy is released
The chemotherapy part of ENHERTU helps destroy the cancer cell as well as other cells nearby

Although ENHERTU is designed to target HER2 on cancer cells, it may affect some healthy cells.
ENHERTU may not work for everyone.

How will I receive ENHERTU?

ENHERTU is given as an intravenous (IV) infusion. You will receive an ENHERTU infusion once every 3 weeks, either at your oncologist’s office or at a nearby infusion center.

Your healthcare provider will give you medicines before your infusion to help prevent nausea and vomiting

The first ENHERTU infusion will take about 90 minutes so the healthcare provider can monitor any potential reactions

Future ENHERTU infusions should take about 30 minutes, if your first infusion was well tolerated

If you miss a planned dose of ENHERTU, call your healthcare provider right away to schedule an appointment. Do not wait until the next planned treatment cycle.

Results with ENHERTU

In a clinical study of 188 adults with previously treated HER2+ advanced stomach cancer,

ENHERTU helped people live longer than with chemotherapy*

Half of the people taking ENHERTU were alive at
12.5 month


Half of the people taking chemotherapy were alive at 8.4 months

This is called median overall survival
A median is the middle number in a set of numbers.

Patients lived about 4 months longer with ENHERTU

*Chemotherapy used in the clinical study was the doctor’s choice between 2 commonly used chemotherapies (irinotecan or paclitaxel).

63 (50%) of 126 people treated with ENHERTU were still alive after 12.5 months vs 23 (37%) of 62 people treated with chemotherapy.

Median overall survival is the midpoint between people who lived the longest and those who lived for the shortest period of time.

In the same clinical study,

Tumors shrank in more people treated with ENHERTU than with chemotherapy§‖

  • 41% (51 of 126) of people saw a confirmed response with ENHERTU and 11% (7 of 62) did with chemotherapy||¶

About 4 out of 10 people
responded to ENHERTU


About 1 out of 10 people
responded to chemotherapy

  • 8% (10 of 126) of people taking ENHERTU achieved a complete response, meaning their tumor could not be seen on imaging tests. This does not always mean the cancer has been cured. No one taking chemotherapy (0 of 62) had a complete response
  • 33% (41 of 126) of people taking ENHERTU achieved a partial response, which means the tumor shrank by at least 30%; 11.3% (7 of 62 people) of those taking chemotherapy had a partial response

84% (106 of 126) of people treated with ENHERTU vs 61% (38 of 62) with chemotherapy had their tumors respond to treatment in at least one of the following ways:


Stop growing

Slow down

This is called the disease control rate#

§Chemotherapy used in the clinical trial was the doctor's choice between 2 commonly used chemotherapies (irinotecan or paclitaxel).

||The number of people who had their tumors shrink is called the objective response rate (or ORR). ORR was achieved by 51 out of 126 people with ENHERTU compared to 7 out of 62 people with chemotherapy.

The response was observed by the treating doctor and then agreed upon by a review panel. A second scan 4 or more weeks after the first was used to confirm the results.

#The 84% shown is the disease control rate, which is the sum of the ORR and stable disease rate. Stable disease means that the tumor did not increase in size by more than 20% nor decrease in size by more than 30%.

What are the possible side effects of ENHERTU?

ENHERTU can cause serious side effects. See What is the most important information I should know about ENHERTU?’’

The most common side effects of ENHERTU, when used in people with HER2-positive gastric or GEJ adenocarcinoma, include:

  • Low red blood cell counts
  • Low white blood cell counts
  • Low platelet counts
  • Nausea
  • Decreased appetite
  • Increased liver function tests
  • Feeling tired
  • Diarrhea
  • Low levels of blood potassium
  • Vomiting
  • Constipation
  • Fever
  • Hair loss

ENHERTU may cause fertility problems in males, which may affect the ability to father children. Talk to your healthcare provider if you have concerns about fertility.

These are not all of the possible side effects of ENHERTU. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Please click here for full Prescribing Information, including Boxed WARNINGS, and click here for Medication Guide.

Downloadable Resources for Patients and Care Partners

Understanding and managing
side effects during treatment

Starting treatment with ENHERTU?
Learn more about ENHERTU, including
Important Safety Information