Efficacy and safety of utidelone plus capecitabine in advanced first-line therapy for metastatic breast cancer: A multicenter real-world study

Background: The purpose of this study was to compare the efficacy and safety of utidelone plus capecitabine for advanced first-line versus second-line or above therapy in metastatic breast cancer patients who had previously received anthracycline and taxane. At the same time, we compared the efficacy of utidelone plus capecitabine and vinorelbine plus cisplatin in advanced first-line treatment of metastatic breast cancer.Patients and methods: A retrospective cohort of 11 patients with metastatic breast cancer previously treated with anthracycline and taxane (including neoadjuvant and adjuvant therapies) for advanced first-line with utidelone plus capecitabine, 32 patients treated with second-line or above, and 60 patients with vinorelbine plus cisplatin between October 2011 and August 2022 was collected. The first and second groups were treated with utidelone plus capecitabine, and the third group was treated with vinorelbine plus cisplatin. The primary endpoint was progression-free survival (PFS), and secondary endpoints were overall survival (OS), objective response rate (ORR), and treatment safety.Results: By 03/31/2023, median PFS reached 11.70 months (95 % CI 0.093-0.141) in utidelone plus capecitabine group in the advanced first-line therapy, compared to 5.60 months (95 % CI 0.025-0.079) in the second-line or above therapy [HR 0.42, (95 % CI 0.226-0.787), P = 0.0077]. In utidelone plus capecitabine, the median OS was not reached in the advanced first-line therapy, with a mean overall survival of 23.16 months (95 % CI 0.198-0.265); whereas the median OS in the second-line or above therapy was 19.50 months (95 % CI 0.083-0.307), with a mean overall survival of 16.89 months (95 % CI 0.136-0.202) [HR 0.26, (95 % CI 0.098-0.678), P = 0.0495]. The ORR for advanced first-line therapy was 27.27 % (95%CI 0.060, 0.610) compared with 15.63 % (95%CI 0.053, 0.328) for second-line or above. In advanced first-line therapy, utidelone plus capecitabine was superior to vinorelbine plus cisplatin with a median PFS of 6.12 months (95 % CI 0.051-0.072) [HR 0.49, (95 % CI 0.286-0.839), P = 0.0291]. Compared with utidelone plus capecitabine, the median OS in vinorelbine plus cisplatin advanced first-line therapy group was 35.37 months (95 % CI 0.258-0.449), and the mean overall survival was 40.79 months (95 % CI 0.315-0.501) [HR 0.54, (95 % CI 0.188-1.568), P = 0.2587]. The ORR for vinorelbine plus cisplatin was 18.33 % (95 % CI 0.095, 0.304). The most common adverse events in our study were neurological toxicity, hand-foot syndrome, hematological toxicity, gastrointestinal toxicity, and hepatic and renal function abnormalities. There were no deaths due to adverse effects during the utidelone plus capecitabine treatment period.Conclusions: In MBC, advanced first-line therapy with utidelone plus capecitabine resulted in more favorable PFS, OS, and ORR than second-line or above therapy. In advanced first-line therapy, utidelone plus capecitabine had superior PFS, and ORR compared with vinorelbine plus cisplatin. This study concludes that utidelone plus capecitabine is a more valuable chemotherapy option in advanced first-line MBC.