Kadcyla (Ado-Trastuzumab Emtansine) for Breast Cancer

What Members Say Top Tips Side Effects FAQs

Kadcyla (ado-trastuzumab emtansine) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat adults with certain HER2-positive breast cancer.

What Members Say

MHT logo These insights are based on 849 comments about Kadcyla from MyBCTeam members. These are the experiences of a small number of individuals and are not meant to be medical advice.

Benefits:

Treatment every three weeks can feel manageable during longer-term care.
Daily routines often stay possible, including work and light activity.
Scans sometimes show stable disease or shrinking tumors.
Infusions often become shorter after the first dose if treatment goes smoothly.

Considerations:

Fatigue, headaches, nausea, constipation, and muscle or joint pain are common.
Low platelets, nosebleeds, bleeding gums, and easy bruising can require dose delays or reductions.
Liver tests and heart function need regular monitoring during treatment.
Neuropathy can worsen and sometimes leads to treatment pauses.

How Kadcyla Works and How It’s Taken

Kadcyla is a HER2-targeted antibody-drug conjugate. This means it is made to find cancer cells that have too much HER2, a protein that can help cancer grow.

Kadcyla attaches to HER2-positive cancer cells. Then the drug is taken inside the cell and releases a cancer-killing medicine called DM1. DM1 disrupts tiny structures the cell needs to divide, which can stop the cancer cell from dividing and may lead to cancer cell death.

Doctors prescribe Kadcyla when adults have certain HER2-positive breast cancer and have had specific prior treatments. Kadcyla may be used in different circumstances:

Kadcyla may be used alone for HER2-positive breast cancer that has spread after treatment with trastuzumab and a taxane. Individuals should also have had prior treatment for metastatic disease, or the cancer should have come back during or within six months after finishing adjuvant treatment.
Kadcyla may be used alone after surgery for HER2-positive early breast cancer when invasive cancer remains after treatment given before surgery with a taxane and trastuzumab-based treatment.

Kadcyla is given as an intravenous (IV) infusion, usually once every three weeks in a 21-day cycle.

For breast cancer that has spread, treatment usually continues until the cancer gets worse or side effects become unacceptable. For early breast cancer after surgery, treatment is usually given for 14 cycles unless the cancer comes back or side effects become unacceptable.

Typical Dosing for Breast Cancer

The recommended dose of Kadcyla for breast cancer is 3.6 milligrams per kilogram given as an IV infusion every three weeks.

Doctors may pause treatment, lower the dose, delay the next dose, or stop treatment if side effects are serious or too hard to manage.

This information is based on the prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Top Advice From Members on Kadcyla

MHT logo These insights are based on 849 comments about Kadcyla from MyBCTeam members.

Members who use Kadcyla often say it feels more manageable than some earlier treatments, but they still recommend paying close attention to side effects and how you feel after each infusion. Many members also stress staying in close contact with your care team about symptoms, lab changes, and whether dose adjustments or extra support might help.

1

Keep track of how you feel after each infusion.
“I had 14 rounds of Kadcyla, and it’s not like regular chemo. Mostly had a headache the first couple of days after infusion.”
2

Ask if a lower dose could help you stay on treatment.
“I had low platelets and ended up in the hospital. My oncologist reduced my Kadcyla dose, which works better for me so far, no big problems.”
3

Ask what to expect from infusion timing and premeds.
“I’ve had two Kadcyla sessions. The first one was 90 minutes so they could see how I did with it. The second time it was just 30 minutes.”

Connect with others who understand life with breast cancer. Join MyBCTeam for free.

Kadcyla Side Effects

In clinical trials of Kadcyla used alone for HER2-positive breast cancer, the most common side effects occurred in at least 25 percent of people taking Kadcyla.

For HER2-positive metastatic breast cancer, these side effects included:

Fatigue
Nausea
Musculoskeletal pain
Hemorrhage (bleeding)
Thrombocytopenia (low platelets)
Headache
Increased transaminases
Constipation
Epistaxis (nosebleeds)

For HER2-positive early breast cancer, these side effects included:

Fatigue
Nausea
Increased transaminases
Musculoskeletal pain
Hemorrhage (bleeding)
Thrombocytopenia (low platelets)
Headache
Peripheral neuropathy
Arthralgia (joint pain)

Serious Side Effects and Warnings

Kadcyla can cause serious side effects that may require immediate medical attention. These include:

Liver problems — Liver failure, severe liver injury, and rare deaths can occur.
Heart problems — Reduced heart function can occur.
Fetal harm — Kadcyla can harm your baby if you are pregnant.
Lung problems — Interstitial lung disease or pneumonitis can occur.
Infusion-related reactions — Reactions can happen during or soon after the infusion.
Hypersensitivity reactions — Serious allergic reactions can occur.
Serious bleeding — Severe bleeding can occur.
Severe low platelet count — This can raise the risk of bleeding.
Nerve problems — Peripheral neuropathy can occur, usually in the hands or feet.
Injection-site leakage into nearby tissue — Extravasation can cause pain, tenderness, skin irritation, or swelling.
Tumor lysis syndrome — This is a serious reaction caused by the rapid breakdown of cancer cells.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Kadcyla

Before starting Kadcyla, your doctor will test or check for:

Whether your breast cancer is HER2-positive using an FDA-authorized test
Liver function, including transaminases and bilirubin
Heart function, including left ventricular ejection fraction (LVEF)
Pregnancy status if you can become pregnant

Tell your doctor about all medications you take, including prescription drugs, over-the-counter medicines, and supplements.

If you miss a planned dose, it should be given as soon as possible. Do not wait until the next planned cycle.

Kadcyla can harm your baby if you are pregnant. Your doctor should verify pregnancy status before you start treatment. Females who can become pregnant should use effective birth control during treatment and for seven months after the last dose.

Males with female partners who can become pregnant should use effective birth control during treatment and for four months after the last dose. Do not breastfeed during treatment with Kadcyla and for seven months after the last dose.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Kadcyla?

In a study of people with HER2-positive metastatic breast cancer, Kadcyla improved median progression-free survival to 9.6 months. This means people lived longer without the cancer getting worse. The comparison treatment was with a different chemotherapy combination of lapatinib plus capecitabine, which had a median progression-free survival of 6.4 months.

Median overall survival was 30.9 months with Kadcyla, compared to 25.1 months with lapatinib plus capecitabine. An objective response happened in 43.6 percent of people taking Kadcyla, compared with 30.8 percent of people taking lapatinib plus capecitabine.

In a study of HER2-positive early breast cancer with invasive cancer left after treatment before surgery, the three-year invasive disease-free survival rate was 88.3 percent with Kadcyla, compared with 77 percent with trastuzumab.

Can Kadcyla cause low platelets or bleeding in breast cancer treatment?

Yes. In clinical trials, thrombocytopenia (low platelet counts) and hemorrhage (bleeding) were common with Kadcyla. Platelet counts should be checked before starting treatment and before each dose.

Depending on how low the platelet count is, treatment may be delayed, the dose may be reduced, or treatment may be stopped.

What should I do if I miss a dose of Kadcyla for breast cancer?

If a planned dose is delayed or missed, it should be given as soon as possible. It should not be delayed until the next planned cycle. After that, the schedule should be adjusted to keep a three-week interval between doses.