(061) Dose-Limiting Neutropenia with Sacituzumab Govitecan in Adult Patients with Breast Cancer

Poster Abstract: Background / Rationale:
Sacituzumab govitecan is a Trop-2-directed antibody and topoisomerase inhibitor conjugate used in the treatment of metastatic/locally advanced unresectable breast cancer. Despite its efficacy, the occurrence of neutropenia poses a challenge that can be dose-limiting and impact patient survival. This study aims to investigate the patterns of toxicities and dose modifications associated with sacituzumab govitecan. Sacituzumab govitecan is administered as a single chemotherapy agent on days 1 and 8 of a 21-day cycle, which can pose a challenge in managing neutropenia due to varying intervals of therapy and break periods. While primary prophylaxis with granulocyte-colony stimulating factor (GCSF) is not recommended by the NCCN guidelines for sacituzumab govitecan, the manufacturer recommends withholding doses, dose modification, and GCSF support for managing severe neutropenia. The findings of this study will determine the incidence of dose-limiting neutropenia associated with sacituzumab govitecan and how doses are consequently modified, and shed light on optimizing treatment strategies to improve patient outcomes with sacituzumab govitecan for breast cancer.

Objectives:
The primary objective is to determine the incidence of dose-limiting neutropenia associated with sacituzumab govitecan. Secondary objectives include describing the pattern of dose-limiting neutropenia, determining incidence of recurrent dose-limiting neutropenia and febrile neutropenia, and describing the clinical practice of secondary GCSF prophylaxis and neutropenia management.

Methods:
This is a single-center, retrospective observational study in which all adult patients with breast cancer who received at least one dose of sacituzumab govitecan from April 2020 to November 2023 at the University of Maryland Medical Center were observed for incidences of dose-limiting neutropenia as outlined in the package insert. Patients who received chemotherapy two weeks prior to sacituzumab govitecan administration, and with a baseline absolute neutrophil count (ANC) less than 1,000/mm3 are excluded. Each dose of sacituzumab govitecan was reviewed and noted for neutropenia leading to dose reduction, delay, and omission. The ANC on day 1 and day 8 dose of every cycle were collected, and dose-limiting neutropenia is described by CTCAE grading, duration, and frequency of recurrence. In addition, GCSF use prior to each dose is recorded and described as either primary or secondary prophylaxis. Convenience sampling was used to conduct the research, and descriptive statistics was used to analyze baseline characteristics.

Results:
Not available; results pending

Discussion /

Conclusion:
Not available; results pending

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