Analysis Illuminates Real-World Use of Sacituzumab Govitecan in Metastatic Triple-Negative Breast Cancer

Sacituzumab govitecan showed “effectiveness and a manageable safety profile” in a recent real-world analysis of patients with previously treated metastatic triple-negative breast cancer (mTNBC).

Rita Nanda, MD, of the University of Chicago, and colleagues conducted the real-world analysis and presented their findings at the 2024 San Antonio Breast Cancer Symposium.

Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate, is approved for patients with previously treated mTNBC and HR-positive/HER2-negative metastatic breast cancer. The antibody-drug conjugate showed a “statistically significant and clinically meaningful benefit” in progression-free survival (PFS) and overall survival (OS) compared with single-agent chemotherapy in the phase 3 ASCENT study.

The trial also showed that sacituzumab govitecan had a “manageable safety profile,” with the most reported toxicities being neutropenia and diarrhea, which “were with established guidance.”

Dr. Nanda and colleagues used the Flatiron Health database to analyze the real-world efficacy of sacituzumab govitecan and describe the incidence and management of neutropenia in this patient population. The study included 381 patients with mTNBC who received treatment with the antibody-drug conjugate as a second-line or later therapy from April 2020 to June 2023.

Patients received a median of two prior lines of treatment in the metastatic setting, with 31% receiving sacituzumab govitecan in the second line and 69% receiving it in the third line or later. Patients received a median of 12 doses of sacituzumab govitecan, with 74 being the maximum number of doses administered during the study period. The median treatment duration was four months.

The median patient age was 61 years and 18% of patients were Black. Among the patients, 17% had an Eastern Cooperative Oncology Group performance status of at least 2, 25% had de novo metastatic disease, and 78% received treatment in community centers only.

With a median follow-up of 8.7 months, the median real-world OS was 11.3 months (95% CI, 9.9-13), with a median of 5.6 months to next treatment or death (95% CI, 5-6.4).

Neutropenia of grade 2 or higher occurred in 57% of patients, with grade 3 or higher reported in 27%. More than half of patients (59%) received granulocyte colony-stimulating factor (G-CSF), with 31% receiving it as prophylaxis only. One-fifth of patients received G-CSF as primary prophylaxis, 9% received it as secondary prophylaxis, and 1% received it as primary and secondary prophylaxis. Neutropenia of grade 3 or higher occurred in 10% of patients after any G-CSF prophylaxis and in 4% of those who received primary prophylaxis only.

The median time from the start of sacituzumab govitecan to the first onset of neutropenia grade 3 or higher subsequent to G-CSF use was 48 days among patients who received primary prophylaxis only. Therapeutic-only use of G-CSF occurred in 6% of patients, with a median time of nine days to onset of neutropenia grade 3 or higher. Nearly one-quarter (21%) of patients received both prophylactic and therapeutic G-CSF during treatment. Among the 41% of patients who did not receive G-CSF during treatment, 13% experienced neutropenia of grade 3 or higher, with a median time to onset of eight days.

With the “low incidence of neutropenia” observed among patients receiving G-CSF prophylaxis, study authors suggested that it can “be effectively prevented with G-CSF prophylaxis” in patients receiving sacituzumab govitecan.

Based on these results, the study investigators concluded that the real-world safety and efficacy were “consistent with findings from the ASCENT study and other real-world studies.”

Reference

Nanda R, Yam C, Spring L, et al. Management of Neutropenia and Effectiveness of Sacituzumab Govitecan (SG) in Patients (pts) With Metastatic Triple Negative Breast Cancer (mTNBC) Treated in Real World Settings in the United States.  Presented at the 2024 San Antonio Breast Cancer Symposium; December 10-13, 2023; San Antonio, Texas.