Almost half of patients with metastatic hormone receptor (HR)-positive breast cancer treated with everolimus and exemestane required a dose reduction or interruption of everolimus during the first treatment cycle, according to a case series published in the journal Supportive Care in Cancer.1
Endocrine therapy continues to be the standard therapy for patients with metastatic HR-positive breast cancer, but exemestane in combination with everolimus has demonstrated improved progression-free survival.
However, this combination has been associated with increase adverse events compared with exemestane alone. Therefore, researchers sought to determine the frequency and timing of everolimus dose reductions and/or interruptions due to toxicity.
For the single-center retrospective case series, researchers analyzed data from 46 patients with metastatic HR-positive disease who received care at The James Cancer Hospital and Solove Research Institute in Columbus, Ohio. All patients had received everolimus plus exemestane between May 2012 and July 2013.
Researchers found that 45.6% of patients experienced first-cycle dose reduction or interruptions, with a median time to dose reduction or interruption of 14 days. The most frequently reported adverse events leading to dose reduction or interruption were stomatitis, fatigue, and diarrhea.
In terms of efficacy, the median progression-free survival was 6.2 months.
“This early onset of adverse events requires thorough patient education and close clinical monitoring during the first 28 days of therapy,” the authors conclude.
1. Vargo CA, Berger MJ, Phillips G, Mrozek E. Occurrence and characterization of everolimus adverse events during first and subsequent cycles in the treatment of metastatic breast cancer [published online ahead of print February 4, 2016]. Supp Care Cancer. doi:10.1007/s00520-016-3105-6.