Kadcyla Continues to Improve Survival in HER2-Positive Early-Stage Breast Cancer
Five more years of follow-up results from the KATHERINE trial showed that Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine) improved both overall survival and progression-free survival compared to Herceptin (chemical name: trastuzumab) in people diagnosed with early-stage, HER2-positive breast cancer who have residual disease after chemotherapy and anti-HER2 therapy before surgery.
Overall survival is how long a person lives whether or not the cancer grows, and progression-free survival is how long a person lives before the cancer grows.
The research was presented on Dec. 8, 2023, at the San Antonio Breast Cancer Symposium. Read the abstract of “Phase III study of adjuvant ado-trastuzumab emtansine vs trastuzumab for residual invasive HER2-positive early breast cancer after neoadjuvant chemotherapy and HER2-targeted therapy: KATHERINE final IDFS and updated OS analysis.”
Treatments given before surgery to remove cancer are called neoadjuvant treatments. One way that doctors judge the effectiveness of neoadjuvant treatments is to look at the tissue removed during surgery to see if any active cancer cells are present. If no active cancer cells are present, doctors call it a pathologic complete response or pCR. If there are active cancer cells present in the tissue removed, this cancer is called residual disease.
Why do the study?
Doctors know that people diagnosed with early-stage, HER2-positive breast cancer who have residual disease after neoadjuvant treatments have a worse prognosis and a higher risk of the cancer coming back (recurrence) than people who have a pCR after neoadjuvant treatment.
When the KATHERINE study started, Herceptin after surgery was the standard of care for people with residual disease after neoadjuvant chemotherapy plus Herceptin, or plus Herceptin and Perjeta (chemical name: pertuzumab).
Researchers wanted to see if Kadcyla after surgery would offer more benefits than Herceptin after surgery for this type of residual breast cancer.
Results presented at the 2018 San Antonio Breast Cancer Symposium after three years of follow-up suggested that Kadcyla offered better disease-free survival than Herceptin. These results led to the U.S. Food and Drug Administration (FDA) approving Kadcyla for early-stage, HER2-positive breast cancer with residual disease after neoadjuvant chemotherapy.
These latest results come after 8.4 years of follow-up.
About the KATHERINE study
The study included 1,486 people diagnosed with early-stage, HER2-positive breast cancer between April 2013 and December 2015. All the people received a minimum of:
six cycles of chemotherapy
nine weeks of Herceptin
People were allowed to receive a second anti-HER2 targeted therapy, like Perjeta, if their doctor recommended it.
After surgery to remove the cancer, all the people had residual disease.
Within 12 weeks of surgery, the researchers randomly assigned:
743 people to receive 14 cycles of Kadcyla
743 people to receive 14 cycles of Herceptin
This latest analysis showed that Kadcyla reduced the risk of recurrence by 46% and reduced the risk of death by 34% compared to Herceptin.
At seven years of follow-up:
80.8% of people receiving Kadcyla were alive with no recurrence
67.1% of people receiving Herceptin were alive with no recurrence
89.1% of people receiving Kadcyla were alive
84.4% of people receiving Herceptin were alive
Rates of serious side effects were low:
two people (0.3%) who received Kadcyla had a serious side effect
four people (0.6%) who received Herceptin had a serious side effect
“T-DM1 is the first targeted therapy to provide significant survival benefit in people with higher risk of recurrence due to finding residual invasive cancer in their surgery specimen following neoadjuvant treatment for HER2-positive, early breast cancer,” said Sibylle Loibl, MD, PhD, who presented the results. Dr. Loibl is chair of the German Breast Group associate professor of obstetrics and gynecology at the Goethe University of Frankfurt.
“After a median follow-up of more than eight years, we have shown a statistically significant overall reduction in the risk of death by 34% with T-DM1 compared with trastuzumab, with a clinically meaningful absolute benefit in the overall survival rates of 4.7% at seven years,” Dr. Loibl continued. “This benefit was seen irrespective of the extent of disease at presentation, HR status, and presence or absence of cancer in lymph nodes removed at the time of surgery.”
What this means for you
These latest KATHERINE results underscore the benefits of Kadcyla for people with residual disease after neoadjuvant chemotherapy and surgery for early-stage, HER2-positive breast cancer.
After the FDA approval of Kadcyla for residual early-stage, HER2-positive breast cancer in 2019, it became the standard of care for this type of breast cancer.
The longer follow-up offers both oncologists and people with this type of breast cancer reassurance that the benefits — especially the overall survival benefits — of Kadcyla persist.
— Last updated on February 9, 2024 at 6:04 PM