Introduction
The BOLERO-21 trial demonstrated significant clinical benefit and a tolerable toxicity profile of combination therapy with everolimus and exemestane in post-menopausal females with hormone receptor positive metastatic breast cancer, after prior progression on hormone therapy. We present the local experience using this combination with respect to efficacy as well as the incidence and severity of side effects at a single Australian cancer centre.
Materials and Methods
We retrospectively reviewed data from 21 patients who received everolimus in combination with exemestane. Efficacy was assessed by patient’s response on imaging and measurement of tumour markers Ca15.3 and carcinoembryonic antigen (CEA).
Safety assessments were according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. Treatment interruptions and dose modifications were collected from patient records.
Results
The median PFS/Time to treatment change in our cohort was 4.6 months (range 1 – 14 months), slightly shorter than the median PFS of 6.9 months (HR 0.43; 95% CI 0.35-0.54) reported in the BOLERO-2 study, likely secondary to a smaller population and more elderly patients in our cohort.
The median duration of therapy was 5 months (range 3 -14 months). Overall the clinical benefit rate was 81% (n=17), with a response rate of 47% (n=10).
The administration of everolimus with exemestane was mostly well tolerated. Most of the everolimus-associated adverse events occurred soon after initiation of therapy, and were typically of mild or moderate severity. The adverse events were managed with dose reduction and treatment interruption. The median duration of therapy was 5 months (range 3 -14 months). The reason for discontinuation of therapy was distributed between toxicity (8 patients) and disease progression (13 patients).