FDA Approval of Trodelvy for Metastatic Breast Cancer Subset Allows Patients to 'Live Longer and Live Better’

With the recent Food and Drug Administration (FDA) approval of Trodelvy (sacituzumab govitecan-hziy), patients with HR-positive, HER2-negative metastatic breast cancer now have a treatment option to potentially allow them “to live longer and live better,” one expert said.

Oftentimes, patients with HR-positive, HER2-negative metastatic breast cancer have been previously treated with an endocrine-based therapy and other chemotherapies. Once those options have been attempted, patients used to have very few treatments to consider before this FDA approval.

“When this happens, cancers typically don’t derive a lot of benefit from standard chemotherapy,” said Dr. Sara M. Tolaney, chief of the division of breast oncology at Dana-Farber Cancer Institute in Boston, in an interview with CURE®. “It’s an area where we really needed to have better therapies available.”

Trodelvy is a unique drug because it is an antibody drug conjugate, which delivers chemotherapy in a targeted manner into the cancer cell, Tolaney explained. She said that antibody drug conjugates often perform much better than standard chemotherapy in this setting, leading patients to potentially live longer and have an improved quality of life.

Trodelvy offers a more direct way to deliver chemotherapy directly to cancer cells.

“Some people think of these drugs as smart bombs because they are trying to hone in on a particular receptor that’s on the cancer cell and use that as a way to target the cancer cells,” Tolaney said. “It allows us to develop an antibody against that particular receptor on a cancer cell and tag that antibody to very potent chemotherapy drugs. And so that way, you get delivery of that very potent chemotherapy into that cancer cell, which is a much more effective way to deliver high doses of chemotherapy.”

Before the FDA approved Trodelvy for patients with HR-positive, HER2-negative metastatic breast cancer, oncologists would typically turn towards another chemotherapy drug when other options have been exhausted like endocrine therapy, CDK4/6 inhibitors and at least two lines of standard chemotherapy.

The TROPiCS-02 trial — evidence which supported the approval of Trodelvy — compared standard chemotherapy drugs that would be considered at this point such as eribulin, capecitabine, gemcitabine and vinorelbine with Trodelvy. Tolaney, who was the lead investigator for the TROPiCS-02 trial, said that Trodelvy “did result in better control of the cancer.”

In particular, treatment with Trodelvy contributed to an overall survival rate (the time patients with cancer are alive after treatment or diagnosis) of 14.4 months compared with 11.2 months in patients treated with chemotherapy. In addition, patients treated with Trodelvy also had a 34% lower risk for cancer progression or death versus those treated with chemotherapy.

Treatment with Trodelvy for patients with HR-positive, HER2-negative metastatic breast cancer do come with some side effects.

“I think of the side effects from (Trodelvy) being chemotherapy-like side effects because, in essence, this is targeted delivery of chemotherapy,” Tolaney said. “What we do see with (Trodelvy) is that people do lose their hair from this drug, it does cause a lowering of white blood cell counts and it can cause mild, intermittent diarrhea.”

She added that side effects like low white blood cell counts may be mitigated with growth factors to stimulate white blood cell production. Also, patients who have intermittent diarrhea from the drug may take antidiarrheal drugs, leading it to be well managed.

Although the FDA approval of Trodelvy does provide a substantial benefit to patients with HR-positive, HER2-negative metastatic breast cancer, more progress needs to be made in this area.

“We still aren’t curing patients with metastatic hormone receptor-positive disease,” Tolaney said. “So there definitely is a need to do better.”

Tolaney explained that progress in this space is already in the works.

“There have been multiple new drugs that actually have been approved — just recently even — and more anticipated to be approved for hormone receptor-positive disease even later this year,” she said. “We are making headway. And it’s really nice to see that there’s so many new options that are emerging for this specific patient population, which I think is really exciting to see.”

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