On April 22, 2020, the U.S. Food and Drug Administration (FDA) granted accelerated approval to Trodelvy (chemical name: sacituzumab govitecan-hziy) to treat adults diagnosed with metastatic triple-negative breast cancer who have received at least two previous treatments for metastatic disease.
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.
Trodelvy is an immune targeted therapy medicine. It is made up of:
- sacituzumab, a type of immune cell 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 FDA’s approval of Trodelvy is based on results from a phase I/II study published on Feb. 21, 2019, in The New England Journal of Medicine. The study included 108 people diagnosed with metastatic triple-negative breast cancer that had been treated with at least two previous therapies for metastatic disease. The people were followed for about 9.7 months.
The results showed that:
- three of the cancers completely responded to Trodelvy, meaning the cancers became undetectable
- 33 of the cancers partially responded to Trodelvy, meaning the cancers stopped growing or shrank
This means the response rate was 33.3%. Overall, half of the cancers responded to Trodelvy for longer than 7.7 months and half responded for shorter periods of time.
“In our trial, Trodelvy demonstrated clinically meaningful responses in patients with difficult-to-treat metastatic triple-negative breast cancer and moves the needle towards better outcomes for patients with metastatic breast cancer,” said Aditya Bardia, M.D., director of precision medicine at the Center for Breast Cancer at Massachusetts General Hospital Cancer Center and lead author of the study.
The phase III ASCENT study looking at Trodelvy was recently stopped because the results were so encouraging. Continued approval of Trodelvy is likely to be based on results from the ASCENT study.
Trodelvy side effects
In the phase I/II study, 85% of the people treated with Trodelvy had a severe (grade three or four) side effect. About 32% of the people in the study had serious side effects. Three people stopped treatment because of side effects.
The most common side effects caused by Trodelvy are:
- low white blood cell counts
- hair loss
- decreased appetite
- abdominal pain
The severe side effects that Trodelvy may cause are:
- Severe neutropenia: Neutropenia means you have abnormally low levels of neutrophils, a type of white blood cell. People with neutropenia have a much higher risk of getting serious infections. Your doctor will monitor your neutrophil counts while you are being treated with Trodelvy. If you develop neutropenia, you may be treated with a granulocyte-colony stimulating factor medicine such as Neupogen (chemical name: filgrastim), Neulasta (chemical name: pegfilgrastim), or Zarxio (chemical name: filgrastim-sndz).
- Severe diarrhea: Severe diarrhea can cause dehydration, low blood pressure, and severe kidney problems. Tell your doctor about any diarrhea you have so it can be treated right away.
What this means for you
If you’ve been diagnosed with metastatic triple-negative breast cancer and have received at least two previous treatments for metastatic disease and are considering which treatment to try next, you may want to talk to your doctor about Trodelvy. Together, you can decide if Trodelvy is right for you and your unique situation.
Written by: Jamie DePolo, senior editor