A long-term study confirmed that ado-trastuzumab emtansine (also called T-DM1 and sold under the brand name Kadcyla), a targeted therapy for HER2-positive early breast cancer, improves survival rates. According to final trial results, 89.1 percent of people who received T-DM1 were alive after seven years, compared to 84.4 percent of those treated with trastuzumab (sold as Herceptin).

T-DM1 is an antibody-drug conjugate. It links trastuzumab to the chemotherapy drug emtansine. This combination delivers chemotherapy directly to breast cancer cells, helping to reduce damage to healthy tissue.

The study included 1,486 people with HER2-positive early breast cancer who still had signs of cancer after initial treatment with chemotherapy and HER2-targeted therapy. They were randomly chosen to receive either T-DM1 or trastuzumab for 14 treatment cycles. The main goal was to see how long people stayed cancer-free, while overall survival was also measured.

The study also measured how long participants lived without showing signs of breast cancer, known as disease-free survival. After a median 8.4 years of follow-up, results showed T-DM1 improved disease-free survival by 13.7 percentage points (80.8 percent vs. 67.1 percent with trastuzumab). T-DM1 also significantly reduced the risk of death compared to trastuzumab alone.

However, T-DM1 was linked to more severe side effects compared with trastuzumab. In the study, 26.1 percent of participants taking T-DM1 experienced more severe side effects, compared to 15.7 percent in the trastuzumab group.

Decade-Old Treatment Still Proving Its Value

Kadcycle was first approved by the U.S. Food and Drug Administration in 2013 for treating advanced HER2-positive breast cancer, and it has since become the standard of care. These latest findings reinforce its long-term benefits, showing that it may reduce the risk of recurrence and improve survival outcomes.

If you’re living with HER2-positive early breast cancer and have questions about treatment options, talk with your healthcare provider. They can help develop a personalized treatment plan to support your specific needs and goals.

Here are six facts you should know about HER2-positive breast cancer treatment.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. More than 76,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Are you living with HER2-positive breast cancer? Have you or a loved one undergone treatment with T-DM1? Share your experiences in the comments below, start a conversation on your Activities page, or connect with like-minded members in Groups.