Trodelvy use in advanced triple negative breast cancer in Australia (TRACIE): Study design and interim analysis.

e13130 Background: Sacituzumab govitecan (SG) is a novel option for advanced triple-negative breast cancer (TNBC), offering improvement in progression-free (PFS) and overall survival (OS). Further real-world data is needed on the patterns of use and treatment outcomes of SG. Methods: TRACIE is a secondary data analysis of advanced TNBC patients in Australia who received SG through an Expanded Access Program (Oct 2021- Apr 2022) or via government reimbursement scheme (from May 2022) in ≥2L setting. Data from 150 patients including clinicopathologic characteristics, treatment patterns, adverse events and treatment outcomes in routine clinical practice are being collected. Results: This is an interim analysis of the first 112 patients from 17 sites (median follow up 25.3 months). Median age was 54.5 years (IQR 49.5-64.5; 25% ≥65 years). At time of SG initiation, 71.5% of patients were ECOG 0-1. 87.5% underwent germline testing, of which 11.2% had a BRCA1/2 pathogenic variant. 79.5% had relapsed metastatic disease. The most common metastatic sites were nodal (58.9%), liver (42%) and lung (29.5%). 7.1% of patients had brain metastases at time of SG initiation. 87.5% had a biopsy in the metastatic setting, of which 80.6% had hormone receptor negative disease, while 19.4% had ER/PR staining of < 10%. 60.2% of tumours were HER2 negative (0 on IHC), while 39.8% were HER2 low (1+ or 2+ on IHC, ISH negative). 62.5% had received ≥2 prior lines of therapy in the metastatic setting. The most common chemotherapy regimens were capecitabine (20.5%), eribulin (17%) and carboplatin/gemcitabine (15.2%). 25% received immunotherapy prior to SG. Median time from metastatic diagnosis to SG initiation was 18.5 months. 92% commenced SG at full dose, with 23.3% requiring dose reductions due to toxicity (14.8%) and clinician decision (7.8%). The most common toxicities were diarrhea (9.8%), neutropenia (5.4%) and fatigue (4.5%). Granulocyte-colony stimulating factor was administered to 7.1% of patients as primary prophylaxis and 32.1% as secondary prophylaxis. At time of analysis, 82.1% of patients discontinued SG due to progressive disease (78.3%), toxicity (9.8%), unspecified reasons without toxicity (8.7%), and death (3.3%). Most common toxicities leading to SG discontinuation were nausea (4.5%), neutropenia (3.6%), anaemia (2.7%), fatigue (2.7%) and diarrhoea (2.7%), with most patients experiencing multiple toxicities. Median time to next treatment was 6.2 months (95% CI 5.2-8.0). Median PFS and OS were 9.5 (95% CI 8.4-11.5) and 13.1 months (95% CI 9.5-17.5), respectively. Conclusions: Interim analysis of real-world data for advanced TNBC patients treated with SG demonstrate encouraging PFS and OS in an aggressive breast cancer subtype, comparable to the ASCENT clinical trial, with acceptable tolerability and no unexpected toxicity. Future presentation of treatment outcomes including subgroup analysis is warranted.