Information for Healthcare Providers / Patients

Kadcyla® (ado-trastuzumab emtansine)

Side Effect Reporting

You may report side effects to the FDA at (800) FDA-1088 or

You may also report side effects to Genentech at (888) 835-2555.

What it Treats

Kadcyla®(ado-trastuzumab emtansine) is approved, as a single medicine, for the treatment of people with HER2-positive metastatic breast cancer (mBC) who have received prior treatment with Herceptin® (trastuzumab) and a taxane chemotherapy. People should either:

  • Have already been treated for their metastatic cancer, or
  • Have had their early-stage cancer come back during or within six months after they completed a course of treatment following surgery.

Important Safety Information

KADCYLA is not the same medicine as trastuzumab (Herceptin)

There are possible serious side effects of KADCYLA. The patient’s doctor may do tests before starting KADCYLA and before each dose to monitor for these side effects. KADCYLA treatment may be stopped or the dose may be lowered if the patient experiences any of these side effects. Patients must contact their doctor right away if they experience any of these symptoms.

Liver Problems

  • KADCYLA may cause severe liver problems that can be life-threatening. Symptoms of liver problems may include vomiting, eating disorder (anorexia), nausea, stomach pain, yellowing of the skin (jaundice), dark urine, or itching

Heart Problems

  • KADCYLA may cause heart problems, including those without symptoms (such as reduced heart function) and those with symptoms (such as congestive heart failure). Symptoms may include swelling of the ankles or legs, shortness of breath, cough, rapid weight gain of greater than 5lbs in less than 24 hours, dizziness or loss of consciousness, or irregular heart beat


  • Receiving KADCYLA during pregnancy can result in the death of an unborn baby and birth defects. Birth control should be used while patients receive KADCYLA and for 6 months after their last dose of KADCYLA
  • If patients are exposed to KADCYLA during pregnancy, they must contact their healthcare provider right away; they are also encouraged to enroll in the MotHER Pregnancy Registry by contacting 1 (800) 690-6720
  • If patients are mothers who are breastfeeding, they should talk with their doctor about either stopping breastfeeding or stopping KADCYLA

Additional possible serious side effects of KADCYLA

Lung Problems

  • KADCYLA may cause lung problems, including inflammation of the lung tissue, which can be life- threatening. Signs of lung problems may include trouble breathing, cough, tiredness, and fluid in the lungs

Infusion-Related Reactions

  • Symptoms of an infusion-related reaction may include one or more of the following: the skin getting hot or red (flushing), chills, fever, trouble breathing, low blood pressure, wheezing, tightening of the muscles in the chest around the airways, or a fast heartbeat. The patient’s doctor will monitor the patient for infusion related reactions

Serious Bleeding

  • KADCYLA can cause life-threatening bleeding. Taking KADCYLA with other medications used to thin your blood (antiplatelet) or prevent blood clots (anticoagulation) can increase the risk of bleeding. The patient’s doctor should provide additional monitoring if the patient is taking one of these other drugs while on KADCYLA. Life-threatening bleeding may also happen with KADCYLA even when blood thinners are not also being taken

Low Platelet Count

  • Low platelet count may happen during treatment with KADCYLA. Platelets are cells in the blood that help the blood clot

Nerve Damage

  • Symptoms may include numbness and tingling, burning or sharp pain, sensitivity to touch, lack of coordination, or muscle weakness or loss of muscle function

Skin Reactions Around the Infusion Site 

  • KADCYLA may leak from the vein or needle and cause reactions such as redness, tenderness, skin irritation, or pain or swelling at the infusion site. If this happens, it is more likely to happen within 24 hours of the infusion

HER2 testing and KADCYLA 

Patients must have a HER2 test to determine if their cancer is HER2-positive before taking KADCYLA as benefit has only been shown in patients whose tumors are HER2-positive.

Most common side effects of KADCYLA

The most common side effects seen in people taking KADCYLA were:

  • Tiredness
  • Nausea
  • Pain that affects the bones, muscles, ligaments, and tendons
  • Bleeding
  • Low platelet count
  • Headache
  • Liver problems
  • Constipation
  • Nosebleeds

Report side effects to the FDA at (800) FDA-1088 or Patients and caregivers may also report side effects to Genentech at (888) 835-2555.

For full Prescribing Information and Boxed WARNINGS on KADCYLA please visit

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