Abstract P2-08-11: Real-world safety of sacituzumab govitecan in patients with advanced triple receptor-negative breast cancer in a tertiary centre in the United Kingdom

Abstract Background: Sacituzumab Govitecan (SG) is a new treatment option in the pre-treated advanced triple negative breast cancer (aTNBC) setting. Since the regulatory approval of SG in the UK in August 2022, there remains little real-world evidence on its safety for patients with aTNBC. Its registration study documented high rates of myelosuppression in this population. In this analysis, we investigated the incidence of neutropenia in patients with aTNBC treated with SG in a large tertiary centre in the UK and its impact on patient management. Methods: We retrospectively collected data on patients with aTNBC treated with at least one dose of SG between September 2022 and September 2023 at the Royal Marsden Hospital, London. We collected clinical data from the electronic patient records and analysed them with descriptive statistics. Results: Thirty-nine patients were included in the analysis. Of these, 28/39 (71.7%) experienced neutropenia of any grade. This was grade 1 in 15/28 (53.5%), grade 2 in 6/28 (21.4%), grade 3 in 7/28 (25.0%) and grade 4 in 1/28 (3.6%). Four patients (14.8%) experienced febrile neutropenia requiring antibiotics and hospitalisation. In 15/28 (53.6%), neutropenia occurred prior to Day 1 of treatment and in 13/28 (46.4%) neutropenia occurred prior to Day 8. Out of the 11 patients who did not experience neutropenia, 7 (63.6%) had upfront GCSF. Out of the 28 patients experience neutropenia, 13 (46.4%) required a dose delay, 5 (17.8%) had a Day 8 dose omitted and 8 (28.6%) had a dose reduction. All patients experiencing neutropenia were prescribed secondary GCSF prophylaxis: 11 (39.3%) following the first episode of neutropenia and 3 (10.7%) after the second episode. Conclusion: Our analysis documented a substantial rate of neutropenia in patients with aTNBC receiving SG. This is consistent with clinical trial data. Our findings support the use of primary GCSF prophylaxis to avoid preventable haematological toxicity and dose adjustments in this setting. Citation Format: Emma Crewe, Imun Gill, Juan Montes Gonzalez, Domingo Cano Gil, Sophie McGrath, Alistair Ring, Stephen Johnston, Alicia FC Okines, Nicolò Matteo Luca Battisti. Real-world safety of sacituzumab govitecan in patients with advanced triple receptor-negative breast cancer in a tertiary centre in the United Kingdom [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P2-08-11.