Compared to chemotherapy, the immune targeted therapy medicine Trodelvy (chemical name: sacituzumab govitecan-hziy) offered better progression-free survival and better overall survival for people diagnosed with metastatic triple-negative breast cancer that had been previously treated with chemotherapy, according to results from the phase III ASCENT trial.
The research was presented on Sept. 19, 2020, at the European Society for Medical Oncology Virtual Congress 2020. Read the abstract of “ASCENT: A randomized phase III study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with previously treated metastatic triple-negative breast cancer (mTNBC).”
Metastatic breast cancer is breast cancer that has spread to parts of the body away from the breast, such as the bones or liver.
Triple-negative breast cancer is cancer that has no receptors for the hormones estrogen and progesterone, as well as no receptors for the HER2 protein. This limits the medicines that can be used to treat the cancer.
Progression-free survival is how long a person lives without the cancer growing. Overall survival is how long a person lives, whether or not the cancer grows.
Trodelvy received accelerated approved from the U.S. Food and Drug Administration to treat breast cancer in April 2020. The approval was based on results from a phase I/II study showing that Trodelvy produced clinically meaningful responses in metastatic triple-negative breast cancer that was not responding to standard chemotherapy. At the time, experts said that continued approval of Trodelvy would likely be based on results from the ASCENT study.
Trodelvy is an immune targeted therapy medicine. It is made up of:
- sacituzumab, a type of protein called a monoclonal antibody, that targets the Trop-2 protein; the Trop-2 protein is found in more than 90% of triple-negative breast cancers
- SN-38, a topoisomerase I inhibitor chemotherapy; topoisomerase I inhibitors work by interfering with the cancer cells’ ability to replicate
- a compound that links the sacituzumab to the SN-38
Doctors call Trodelvy an antibody-drug conjugate. The linking compound attaches (conjugates) the monoclonal antibody sacituzumab to the SN-38 chemotherapy.
Trodelvy is given intravenously, which means the medicine is delivered directly into your bloodstream through an IV or port. Trodelvy is given once weekly on day one and day eight of a continuous 21-day treatment cycle, unless the cancer grows or unacceptable side effects develop.
The ASCENT study
The ASCENT study included 529 people diagnosed with metastatic triple-negative breast cancer that had grown after being treated with two or more chemotherapy regimens.
Selected characteristics of the people in the study include:
- half were younger than 54 and half were older
- half had received more than four previous chemotherapy regimens and half had received fewer
- 61 people had brain metastases
This analysis included results only from people without brain metastases.
The people were randomly assigned to one of two treatments:
- Trodelvy (235 people)
- their doctor’s choice of one of four chemotherapy medicines: Xeloda (chemical name: capecitabine), Halaven (chemical name: eribulin), Navelbine (chemical name: vinorelbine), or Gemzar (chemical name: gemcitabine) (233 people)
The people received treatment until the cancer grew or unacceptable side effects developed.
Progression-free survival was:
- 5.6 months for people treated with Trodelvy
- 1.7 months for people treated with chemotherapy
This difference was statistically significant, which means that it was likely because of the difference in treatment and not just due to chance.
Overall survival was:
- 12.1 months for people treated with Trodelvy
- 6.7 months for people treated with chemotherapy
The results also showed that more of the cancers responded to Trodelvy compared to chemotherapy:
- 35% of the cancers responded at least partially to Trodelvy; 4% responded completely, which means the cancer became undetectable
- 5% of the cancers responded at least partially to chemotherapy; 1% responded completely
“The phase III ASCENT trial is the first phase III study to demonstrate a significant improvement in efficacy with a first-in-class Trop-2-directed antibody-drug conjugate compared with standard chemotherapy in patients with previously treated metastatic triple-negative breast cancer,” lead study author Aditya Bardia, director of precision medicine at the Center for Breast Cancer at Massachusetts General Hospital Cancer Center, said during his virtual presentation at the meeting. “The clinical benefit here confirms the use of sacituzumab govitecan as a standard therapy for patients with pretreated metastatic triple-negative breast cancer.”
Trodelvy side effects
Like almost all cancer medicines, Trodelvy can cause side effects, some of them severe.
The most common side effects caused by Trodelvy in the study were:
- low white blood cell counts
- hair loss
The most common severe side effects were:
- low white blood cell counts
Overall, 4.7% of the people being treated with Trodelvy and 5.4% of people being treated with chemotherapy stopped treatment because of side effects.
What this means for you
If you’ve been diagnosed with metastatic triple-negative breast cancer that has stopped responding to at least two previous chemotherapy regimens, the results from the ASCENT study are very encouraging. As you and your doctor are considering which treatments to try next, you may want to discuss Trodelvy. Together, you can decide if Trodelvy is right for you and your unique situation.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser
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