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Second-line sacituzumab govitecan improves survival in metastatic TNBC

ESMO 2020
In pretreated metastatic TNBC patients, standard of care chemotherapy is associated with low objective response rates (ORRs) and short median progression-free survival (PFS). Results of the phase 3 ASCENT trial show improved ORR rates, and improved survival.

Sacituzumab govitecan is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38, the active metabolite of irinotecan. Trop-2 is expressed in all subtypes of breast cancer and linked to a poor prognoses. SN-38 is released both intracellularly and in the tumour microenvironment. Based on the results of a phase 1/2 trial, the FDA recently approved sacituzumab govitecan for treatment of refractory, metastatic TNBC [1].

In the phase 3 ASCENT study, 468 metastatic TNBC patients who had relapsed or had refractory disease after ≥2 prior chemotherapies in the advanced/metastatic setting were randomised 1:1 to sacituzumab govitecan (10 mg/kg IV on day 1 and 8, every 3 weeks) or single-agent chemotherapy of physicians’ choice (capecitabine, eribulin, vinorelbine, or gemcitabine) until disease progression/unacceptable toxicity [2].

Sacituzumab govitecan compared with chemotherapy significantly improved both median PFS (5.6 vs 1.7 months; HR 0.41; P<0.0001) and median overall survival (12.1 vs 6.7 months; HR 0.48; P<0.0001; see Figure). ORR was 35% for sacituzumab govitecan versus 5% for chemotherapy (P<0.0001). A benefit was observed across all subgroups.

In the safety population (n=482), treatment-related grade ≥3 adverse events were neutropenia (51% vs 33%), diarrhoea (10.5% vs <1%), anaemia (8% vs 5%), and febrile neutropenia (6% vs 2%).

Figure: Overall survival in the phase 3 ASCENT trial [2]

  1. Bardia A, et al. N Engl J Med. 2019;380:741-751.
  2. Bardia A. et al. ASCENT: A randomized phase III study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with previously treated metastatic triple-negative breast cancer (mTNBC). ESMO 2020 Virtual Meeting, abstract LBA17.

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