New oral chemotherapy extends time without progression for MBC
Tesetaxel, a new taxane-based chemotherapy given as a pill, led to longer time without cancer growing when added to treatment with capecitabine (Xeloda) for metastatic, hormone receptor-positive, HER2-negative breast cancer. These results, from the CONTESSA trial, were reported Friday during the San Antonio Breast Cancer Symposium.
Chemotherapy is effective at stopping the growth of metastatic breast cancer, but its effects on quality of life can be difficult for the people getting treatment. Most chemotherapies are given by vein, requiring patients to get the medicine at a cancer center for an hour or longer each visit. Then there are side effects, which can include nausea and vomiting, hair loss, fatigue, insomnia, mouth sores, and others.
Finding effective treatments that have less of an impact on a person’s quality of life is a major research question being approached in different ways, including the introduction of new targeted treatments and new tests to better understand each breast cancer diagnosis. Another way is finding new methods of giving chemotherapy that maintain or improve on the benefits of stopping cancer growth while preserving quality of life.
CONTESSA is a phase III trial exploring whether adding tesetaxel to treatment with capecitabine will lead to people going longer without cancer growing compared to capecitabine alone.
Tesetaxel is a new taxane-based chemotherapy that can be absorbed through the digestive system, allowing it to be given as a pill. Given in previous studies to people with metastatic, hormone receptor-positive, HER2-negative breast cancer, it showed promising results in the rate of people who had cancers that shrank in response to treatment. It also had low rates of hair loss and neuropathy — a numbness, pain, tingling, or burning sensation in the hands or feet.
The dose of tesetaxel is two to five pills, depending on body mass, taken together once every 3 weeks.
Capecitabine is an approved chemotherapy given by pill used in a number of contexts to treat metastatic breast cancer. In the CONTESSA trial, capecitabine was given in a 3-week cycle, participants took capecitabine twice daily for 2 weeks with a 1-week break.
Participants had metastatic, hormone receptor-positive, HER2-negative breast cancer. They had been treated with one other line of taxane-based chemotherapy, either for early-stage or metastatic breast cancer, but could have had any number of lines of treatment with targeted therapy.
The trial had 685 participants who were randomly assigned to one of two treatment arms:
- capecitabine alone
- tesetaxel with a reduced dose of capecitabine
The CONTESSA trial found that the group given a combination of tesetaxel and capecitabine had a longer progression-free survival, meaning they went longer without cancer growing:
- 9.8 months for people given tesetaxel and capecitabine
- 6.9 months for people given capecitabine alone
Adding tesetaxel to treatment also led to a higher overall response rate, meaning more cancers shrunk in response to treatment:
- 57 percent in the tesetaxel plus capecitabine group
- 41 percent in capecitabine alone group
The difference was statistically significant, meaning the effect was not likely to have been caused by chance.
Findings on overall survival, the risk of dying in the time studied, is not yet complete. Researchers expect to have those data in 2022.
The most common side effects in people taking tesetaxel and capecitabine were neutropenia, nausea, and diarrhea. Neutropenia was the most common grade 3 or 4 side effect in the tesetaxel group, meaning there was a severe loss of certain blood cells that requires medical attention:
- 70.9 percent in the tesetaxel and capecitabine group
- 8.3 percent in the capecitabine alone group
In the tesetaxel group, 8.0 percent of participants reported grade 2 alopecia, meaning more than 50 percent hair loss, compared to 0.3 percent in the capecitabine alone group. Neuropathy was another side effect of interest for researchers. The rates of grade 3 or 4 neuropathy were
- 5.9 percent in the tesetaxel and capecitabine group
- 0.9 percent in the capecitabine alone group
What this means for you
The findings in the CONTESSA trial offer a possible new treatment option for metastatic, hormone receptor-positive, HER2-negative breast cancer. Both medicines in the chemotherapy combination are given as a pill, without any need for infusions at the cancer center. The combination had rates of neuropathy and hair loss that are low compared to other chemotherapies, researchers said.
The COVID-19 pandemic has brought extra attention to the ways that treatments are delivered. Having a new chemotherapy that can be taken at home can be helpful in putting off chemotherapy by infusion and regular trips to the cancer center.
This is a positive first step for tesetaxel. The makers will submit a new drug application in 2021 for the Food and Drug Administration to consider approval and to make the medicine available for treatment. In the meantime, research will continue to see if tesetaxel leads to people living longer and to see if can be used in other contexts as well.