The combination of everolimus and trastuzumab shows promise against metastatic breast cancer in pretreated, HER2-positive patients with trastuzumab resistance, according to results of a phase 1/2 study. This targeted, nonchemotherapy regimen provided partial responses in 7 of 47 patients and persistent stable disease (lasting 6 months or longer) in 9 of 47 patients. The regimen produced a clinical benefit rate of 34%, and median progression-free survival was 4.1 month.
The finding that progression-free survival was not affected by PTEN loss supports the concept that PTEN can counteract P13K, and in the absence of PTEN, the mTOR pathway may be activated. Everolimus, the researchers concluded, overcomes PTEN-mediated trastuzumab resistance by inhibiting the mTOR pathway.
The complete study is available online in the July 5 issue of the Journal of Clinical Oncology (http://jco.ascopubs.org/content/early/2011/06/29/JCO.2010.32.2321.full.pdf+html).
To sign up for our newsletter or print publications, please enter your contact information below.
