How was ENHERTU studied?
ENHERTU is a prescription medicine used in adults to treat human epidermal growth factor receptor 2 (HER2)‑positive breast cancer that cannot be removed by surgery or that has spread to other parts of the body (metastatic), and who have received a prior anti-HER2 breast cancer treatment for metastatic disease, or have breast cancer that has come back during or within 6 months of completing treatment for their early-stage breast cancer.
ENHERTU was compared with Kadcyla® (ado-trastuzumab emtansine) in a clinical trial of 524 people who:
- Had HER2+ breast cancer that had spread to other parts of their body or could not be removed by surgery, and
- Had received a prior treatment for HER2+ metastatic breast cancer that came back during or within 6 months of treatment after surgery
In this trial, 261 people were treated with ENHERTU and 263 were treated with Kadcyla.
What were the results of the ENHERTU study?
At 12 months, 150 patients remained on ENHERTU and 51 patients remained on Kadcyla.
*Median progression-free survival (mPFS) was not reached with ENHERTU at the time it was assessed, and mPFS for people taking Kadcyla was about 7 months. Median progression-free survival is the length of time from the start of treatment that half of the people in the study had gone without disease progression. When more than half of the people had lived without disease progression, mPFS has not been reached.
Almost 83% of people had their tumors shrink with ENHERTU and 36% with Kadcyla†‡
More than 8 out of 10 people
responded to ENHERTU
More than 3 out of 10 people
responded to Kadcyla
Of the people who responded to ENHERTU:
- 16% of people achieved a complete response with ENHERTU and 8% treated with Kadcyla.†§ A complete response means the tumor could not be seen on imaging tests
- Nearly 67% of people achieved a partial response with ENHERTU and nearly 28% treated with Kadcyla.†|| A partial response means the tumor shrank by at least 30%
- Nearly 17% of people achieved stable disease with ENHERTU. This means that people did not have their tumor increase in size by more than 20% or decrease in size by more than 30%
†Not statistically significant.
‡205 of 248 people had their tumors shrink with ENHERTU and 87 of 241 people with Kadcyla.
§39 of 248 achieved a complete response with ENHERTU and 20 of 241 people with Kadcyla.
||166 of 248 achieved a partial response with ENHERTU and 67 of 241 people with Kadcyla.
97% of people treated with ENHERTU had their tumor(s) respond to treatment in at least 1 of the following ways:
This is called the disease control rate¶
A variety of patients with HER2+ mBC responded to ENHERTU.
¶The disease control rate is the percentage of patients who have achieved complete response, partial response, or stable disease. 242 of 248 people achieved a disease control rate.
HR, hormone receptor.
What are the possible side effects of ENHERTU?
The most common side effects of ENHERTU, when used in people with breast cancer, include:
- Low white blood cell counts
- Low red blood cell counts
- Increased liver function tests
- Feeling tired
- Low platelet counts
- Hair loss
- Low levels of blood potassium
- Decreased appetite
- Pain in muscles and bones
- Infections of the respiratory tract
- Stomach area (abdominal) pain
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 Daiichi Sankyo at 1-877-437-7763 or to FDA at 1-800-FDA-1088.
HER2, human epidermal growth factor 2; HR, hormone receptor; mBC, metastatic breast cancer.