Evaluation of ixabepilone efficacy and tolerability in metastatic breast cancer

Although microtubule inhibitors are generally used in advanced stages, they provide the opportunity to prolong survival as an alternative when medical oncologists have difficulty finding options in their patients, who typically have a poor prognosis and most of whom are unresponsive to treatment. For this reason, we wanted to investigate the effect of ixabepilone treatment on survival in earlier metastatic lines. Our study also examined the frequency of side effects and survival differences in patients whose dose was reduced or whose treatment was discontinued. Our study includes patients diagnosed with metastatic breast cancer who received ixabepilone treatment between January 2011 and January 2021. Median overall survival (OS) in the group receiving ixabepilone on the 5th line and before was 22.0 months (95% CI: 21.0-22.9), in the group receiving ixabepilone after the 5th line was calculated as 10.0 months (95% CI: 8.9-11.0) (P < .001). Median OS (months) in the group receiving ixabepilone on the 4th line and before was 26.0 (95% CI: 23.6-28.3), in the group receiving ixabepilone after the 4th line was determined as 12.0 (95% CI: 10.5-13.4) (P < .001). Dose reduction or discontinuation of ixabepilone treatment in patients due to side effects did not affect OS and progression-free survival with ixabepilone statistically significantly. Ixabepilone treatment has side effects, similar to all other treatments used in metastatic breast cancer, however, these side effects are manageable. Additionally, since ixabepilone treatment is preferred in patients who have previously received many different chemotherapeutics and experienced cumulative toxicity, the side effects of ixabepilone may seem to be greater than they are. In our study, we showed that ixabepilone treatment has a statistically significant positive effect on survival if preferred in earlier metastatic lines. As similar studies increase in centers where ixabepilone treatment is generally given in advanced metastatic lines, treatment approaches may change in the coming years.