Everolimus in heavily pretreated metastatic breast cancer: Is real world experience different?

Abstract

Drugs targeting mammalian target of rapamycin signaling pathway have been recently approved for treatment of hormone receptor (HR) positive metastatic breast cancer (MBC). However, there is lack of real world data from India on the use of this therapeutic strategy. A retrospective analysis of MBC patients who had recurrence or progression while receiving aromatase inhibitors (AI's) and further treated with everolimus and either tamoxifen/AI/fulvestrant between March 2012 and June 2014, was undertaken. There were 41 patients with median age 55 years, 73% with visceral metastasis, and 73% with ≥2 sites of metastases. Thirty (73%) patients had received 3 prior lines of therapy including AI (100%), tamoxifen (94%), fulvestrant (39%), and chemotherapy (100%) while the remaining had received <3 lines of prior therapy. The commonest Grade 3/4 adverse events were stomatitis (19%), hyperglycemia (new/worsening, 17%), fatigue (14.5%), nonneutropenic infections (14%), anemia (12%) and pneumonitis (7%). Everolimus dose reductions were required in 31% patients. There were 30% partial responses, 38% prolonged disease stabilizations and 32% disease progression as best responses to everolimus. The median progression-free survival was 22 weeks (5 months). Everolimus based treatment has meaningful activity in heavily pretreated patients with HR-positive MBC but is associated with considerable toxicity and requirement for dose adjustment.