Background and Importance Sacituzumab-govitecan (SG) is a new antibody-drug conjugate approved for unresectable/metastatic triple negative breast cancer (TNBC), available from the end of 2022 in the Spanish public health system, so there is still little published real-life data.

Aim and Objectives To analyse the effectiveness and safety of SG in TNBC of patients from the three main hospitals of a city.

Material and Methods Retrospective, observational, and multicentre study was conducted, including all patients treated with SG until July 2023. Data were obtained from the electronic medical record and prescription software. SPSS-Statistics v.21® was used for processing. Variables collected: sex, age, body mass index (BMI), hormone receptor (HR) and human epidermal growth receptor-2 (HER2) status, primary granulocyte-colony-stimulating factor (G-CSF) prophylaxis, location of metastases, breast-cancer-gene (BRCA) mutational status, Eastern-Cooperative-Oncology-Group (ECOG) score, duration of treatment, objective response rate (ORR) according to RECIST-v1.1 criteria, progression-free survival (PFS), overall survival (OS), cause of treatment discontinuation, previous chemotherapy (CT) lines, and adverse effects (AEs) according to Common Terminology Criteria for Adverse Events-v5 (CTCAE).

Results Thirty-six patients were included (100% female); median age 52.5 [Interquartile range (IQR) =64.3–46.8]. Mean BMI 25.8 [standard deviation (SD)=4.9]. 97% HR-negative and 100% HER2-negative. 30.6% received primary prophylaxis with G-CSF. Lung metastases were the most frequent (63.9%), followed by bone (36%), hepatic (30.5%) and ganglionic (25%). 61.1% BRCA-negative, 5.6% BRCA2 and 33.3% not available. Most of the patients had a baseline ECOG 0–1 (75%). To date, 14 patients were still on treatment. ORR is 25% (22.2% partial response and 2.8% complete response), stable disease in 22.2% and progression in the rest. Median PFS was 4 months (IC 95%: 2.9–5.3); Median OS not reached. 47.2% of patients discontinued treatment due to disease progression and 13.9% exits. Median total of SG cycles received was 4 (IQR=8.1–2.4) and a median of 2 (IQR=3–1) previous CT-lines in metastatic-stage.

97.2% of the patients had some AE during treatment. Most frequent were: asthenia (80.5% (G3–4:2.8%)), anaemia (61% (G3–4:8.3%)), neutropenia (50%(G3–4:16.7%)), diarrhoea (44.4% (G3–4:11.1%)), alopecia (44.4% (G3–4:5.5%)). 69.4% had some reduction or delay of dose because of toxicity and no patient discontinued treatment due to an AE.

Conclusion and Relevance Median PFS was lower than in the pivotal ASCENT trial. Although the majority presented some AE, in no case did these force treatment discontinuation. Further studies with a larger sample size and longer follow-up period are needed to confirm these real-life results.

Conflict of Interest No conflict of interest.