Comparing the outcomes of utidelone plus capecitabine versus capecitabine alone in patients with previously treated resistant metastatic breast cancer

The study compared outcomes of utidelone plus capecitabine (Xeloda) versus capecitabine (C) alone in previously treated patients with anthracycline- and taxane-resistant metastatic breast cancer (MBC). The authors found that this combination improved survival compared to C alone in such patients.

Taxanes and anthracyclines are chemotherapies traditionally used to treat early breast cancer. Some patients become resistant to these treatments while developing MBC. Capecitabine is recommended for such patients, but its effect on survival is limited.

Utidelone (U) is a genetically engineered drug similar to epothilones. Epothilones are natural substances that interfere with cell division. This means that U can stop tumors from growing and spreading. A previous small study has shown that U+C had improved tumor response and survival compared to C alone. However, the longer-term impact of U+C in patients with MBC resistant to taxanes and anthracyclines are still unknown.

The study included 405 women with MBC, whose cancer progressed despite undergoing 2-4 prior anthracycline- and taxane-based chemotherapies. 270 of these patients received U+C and 135 received C alone. On average, patients were followed up for 19.6 months in the U+C group and 15.4 months in the C alone group.

The average overall survival was 19.8 months with U+C and 16 months with C alone. Patients receiving U+C had a 25% higher chance of surviving compared with C alone. Overall, 41.3% of the patients from the U+C group and 30.3% from the C alone group were estimated to survive for 2 years.

77.4% of patients from the U+C group and 75.6% from the C alone group had received at least one anticancer therapy after this study. OS was still prolonged to 22.6 months for U+C compared to 17.9 months for C alone even after this subsequent therapy.

The average survival without cancer worsening was 8.4 months for U+C and 4.1 months for C alone. Overall, 45.6% of the U+C group and 23.7% of the C alone group responded to treatment.

Side effects occurred in 54.3% of the U+C group and 35.4% of the C alone group. Serious side effects were reported in 7.9% of the U+C group and 10.8% of the C alone group. Most untoward side effects were nerve problems in the feet (numbness and tingling). 

The study concluded that U+C increased survival compared to C alone in heavily pretreated patients with anthracycline- and taxane-resistant MBC. 

This study was conducted on Chinese patients only. Utidelone is not approved by regulatory authorities yet.