OS benefit of sacituzumab govitecan in pre-treated HR-positive/HER2-negative metastatic breast cancer

Sacituzumab govitecan significantly improved overall survival (OS) compared with the treatment of the physician’s choice (TPC) in patients with pre-treated HR-positive/HER2-negative metastatic breast cancer.

Despite new additional treatment options like CDK4/6 inhibitors, endocrine resistance in patients with HR-positive/HER2-negative metastatic breast cancer eventually develops. For endocrine-resistant disease, sequential single-agent chemotherapy is standard-of-care, however, this treatment is associated with low response rates, poor outcomes, and declining quality-of-life [1]. Sacituzumab govitecan is a first-in-class Trop-2-directed antibody-drug conjugate that has demonstrated significant improvement in progression-free survival (PFS) in pre-treated, endocrine-resistant HR-positive/HER2-negative metastatic breast cancer patients in the phase 3 TROPiCS-02 trial (NCT03901339) [2]. Prof. Hope Rugo (Helen Diller Family Comprehensive Cancer Centre, CA, USA) presented the first OS results from the TROPiCS-02 trial [3].

This randomised, phase 3 trial included 543 participants with locally advanced/metastatic, inoperable HR-positive/HER2-negative metastatic breast cancer, who’s tumours progressed after at least 1 endocrine therapy, taxane, and CDK4/6 inhibitor in any setting, and who received at least 2 but not more than 4 lines of chemotherapy for metastatic disease. Participants were 1:1 randomised to receive sacituzumab govitecan (10 mg/kg, days 1 and 8, every 21 days) or TPC. OS was the key secondary endpoint.

In the second interim analysis median OS for participants treated with sacituzumab govitecan was 14.4 months versus 11.2 months for TPC patients (HR 0.79; P=0.020, see Figure). The OS rate at 12 months was 61% (sacituzumab govitecan) versus 47% (TPC). The overall response rate was 57% versus 38% and the main duration of response was 8.1 months versus 5.6 months for sacituzumab govitecan and TPC, respectively.  The median time-to-deterioration was 4.3 months (sacituzumab govitecan) versus 3.0 months (TPC). Grade ≥3 treatment-related adverse events were observed in 74% versus 60% of patients for sacituzumab govitecan and TPC, respectively.

Based on these results, Prof. Rugo concluded that “the statistically significant and clinically meaningful benefit of sacituzumab govitecan over TPC supports the use of sacituzumab govitecan as a novel therapy for patients with pre-treated HR-positive/HER2-negative metastatic breast cancer.”

1. Burstein HJ, et al. J Clin Oncol. 2021;39(35):3959–3977.
2. Rugo HS, et al. J Clin Oncol. DOI: 0.1200/JCO.22.01002.
3. Rugo HS, et al. Overall survival (OS) results from the phase III TROPiCS-02 study of sacituzumab govitecan (SG) vs treatment of physician's choice (TPC) in patients (pts) with HR+/HER2- metastatic breast cancer (mBC). Abstract LBA76, ESMO Congress 2022, 09–13 September, Paris, France.

Figure: Sacituzumab govitecan treatment improves overall survival probability and overall survival rate of HR-positive/HER2-negative metastatic breast cancer patients, as per 2^nd interim analysis [3].



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Posted on 16 November 202218 March 2024