Trodelvy Associated with Better Benefits Than Chemo in Metastatic Triple-Negative Breast Cancer, Regardless of Agent

Treatment with Trodelvy (sacituzumab govitecan) induced better survival outcomes and responses to therapy than physician’s choice of therapy, regardless of which chemotherapy agent was used, in patients with metastatic triple-negative breast cancer (TNBC), according to an analysis of data from a phase 3 trial.

The results, which were presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, demonstrated that patients who received Trodelvy achieved a more improved benefit in progression-free survival (time during and after treatment when the patient lives without disease progression), overall survival (length of time from either diagnosis or start of treatment that a patient is still alive) and objective response rate (the percentage of patients with partial and complete responses to treatment).

The physician’s choice of chemotherapy options included eribulin, vinorelbine, capecitabine, or gemcitabine. The median progression-free survival was 5.6 months with Trodelvy, 2.1 months with eribulin, 1.6 months with vinorelbine, 1.6 months with capecitabine, and 2.7 months with gemcitabine.

The use of Trodelvy was also associated with prolonged median overall survival over eribulin, vinorelbine, capecitabine, or gemcitabine, at 12.1 months versus 6.9 months, 5.9 months, 5.2 months, and 8.4 months, respectively. Moreover, the study drug elicited an objective response rate of 35%. This outcome was significantly better than the 5%, 4%, 6%, and 3% with eribulin, vinorelbine, capecitabine, or gemcitabine, respectively.

“The efficacy benefit for median (progression-free survival), median (overall survival), and (objective response rate) with (Trodelvy) versus single-agent chemotherapy in the second-line or greater metastatic TNBC setting in ASCENT was retained when evaluating each chemotherapy agent individually,” lead study author Dr. Joyce A. O’Shaughnessy, cochair of breast cancer research and chair of breast cancer prevention research at Baylor-Sammons Cancer Center of Texas Oncology in Dallas, said during a presentation of the data. “These results confirm that (Trodelvy) should be considered as a new standard of care in this patient population.”

For patients with previously treated TNBC, standard treatment has comprised single-agent chemotherapy; however, this approach has been linked with responses rates of under 20% and a short progression-free survival ranging from just 2 to 3 months.

In April 2021, the Food and Drug Administration (FDA) granted Trodelvy a full approval to treat patients with unresectable locally advanced or metastatic TNBC who have received two or more prior systemic therapies, at least one of which was for metastatic disease. The regulatory decision was based on earlier data from the ASCENT trial, which showed that the agent significantly improved survival over physician’s choice of single-agent chemotherapy in patients with metastatic TNBC who were receiving treatment in the second- or later-line setting.

In the analysis of the data, which was presented during the ASCO Annual Meeting, investigators evaluated the safety and efficacy of Trodelvy versus each chemotherapy agent to determine how each drug performed individually.

Of the 529 patients enrolled to the phase 3 study, 235 patients in the study drug group were negative from brain metastases, as were 233 patients in the chemotherapy group. In those who did not receive study drug, eribulin was noted to be the most frequently selected agent (126 patients), followed by vinorelbine (47 patients), capecitabine (31 patients), and gemcitabine (29 patients).

At the time of data cutoff, 15 patients remained on treatment with Trodelvy compared to 0 in the chemotherapy group. The most frequently reported reasons for study discontinuation included disease progression and withdrawn consent.

Additional data showed that of those who responded to treatment with study drug, the complete response rate was 4% and the partial response rate was 31%.

Regarding safety, pivotal treatment-related side effects that were serious or severe experienced with the Trodelvy compared to eribulin included neutropenia (51% vs. 31%), leukopenia (10% vs. 5%), diarrhea (10% vs. 0%), anemia (8% vs. 2%), febrile neutropenia (6% vs. 2%), fatigue (3% vs. 5%) and peripheral neuropathy (0% vs. 2%).

Important serious or severe side effects reported with study drug compared to vinorelbine, capecitabine, and gemcitabine combined included neutropenia (51% vs. 36%), leukopenia (10% vs. 6%), diarrhea (10% vs. 1%), anemia (8% vs. 8%), febrile neutropenia (6% vs. 2%) and fatigue (3% vs. 6%).

Additionally, treatment-emergent side effects resulted in discontinuation in 5% of those who received Trodelvy, 2% of those given eribulin, 10% of those who received vinorelbine, 7% of those given capecitabine, and 9% of those who were administered gemcitabine. Of note, no treatment-related deaths occurred in the Trodelvy group.

“The safety profile of (Trodelvy) versus single-agent chemotherapy in the second-line or greater metastatic TNBC setting in ASCENT was comparable,” O’Shaughnessy concluded.

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