Dr Fisch on the Incidence of Neutropenia With Sacituzumab Govitecan in Advanced Breast Cancer

"[Findings showed 82.6% of patients] had any-grade neutropenia occur, and approximately 50% had grade 3 or higher neutropenia. Furthermore, we found that approximately 50% of patients needed a dose reduction of sacituzumab govitecan; however, [only 8.7%] of patients ended up being hospitalized for sacituzumab govitecan–induced neutropenia, and also [5.4%] had grade 3/4 neutropenic fever.”

Samantha Fisch, MD, second-year internal medicine resident, University of California San Francisco, discusses findings from a single-center retrospective cohort study evaluating the incidence of neutropenia and growth factor use in patients with hormone receptor (HR)–positive/HER2-negative breast cancer or triple-negative breast cancer (TNBC) receiving sacituzumab govitecan-hziy (Trodelvy).

Fisch explained that the retrospective analysis, which was presented at the 2024 San Antonio Breast Cancer Symposium, featured 92 patients with HR-positive/HER2-negative breast cancer (n = 37) or TNBC (n = 55). Findings showed any-grade neutropenia was observed in 82.6% of all patients (TNBC, 83.7%; HR+/HER2–, 81.0%). Grade 3 or higher neutropenia occurred in 53.3% of all patients (TNBC, 58.2%; HR+/HER2–, 45.9%). Grade 3/4 neutropenic fever was reported in 5.4% of all patients; however, all instances occurred in the TNBC cohort, where the rate was 9.1%. Hospitalization due to sacituzumab govitecan–related neutropenia was required in 8.7% of patients, with a median length of stay of 4.5 days (range, 1-10 days).

Dose delays attributed to neutropenia occurred in 15.2% of all patients, 26.4% of patients with TNBC, and 13.5% of patients with HR-positive/HER2-negative breast cancer. The respective rates of dose reductions due to neutropenia were 14.1%, 14.5%, and 13.5%. Only 2.2% of all patients discontinued treatment due to any toxicity, and all were in the HR-positive/HER2–negative cohort. .

Growth factor support was utilized in 87% of patients, including filgrastim (81.5%), pegfilgrastim (13.0%), and both (7.6%). Primary prophylaxis was more common in the HR-positive arm (54.1%) compared with the TNBC arm, where secondary prophylaxis was more common (49.1%).

Fisch and colleagues noted in the presentation of the data that patients who received primary prophylaxis experienced lower rates of grade 3 or higher neutropenia; however, this difference was statistically significant only in the TNBC cohort.