[BOLERO -- another remarkable step in treatment of breast cancer].

The expansion of molecular genetic knowledge leads to targeted therapy which is a common part of cancer treatment. Targeted agents also exist for breast cancer. However, new efficient molecules are urgently needed. On one hand, there are cancer subgroups where we do not have efficient targeted drugs, on the other hand, the results of established cancer therapies can be improved by interfering with another signal transduction pathway. Everolimus is a targeted agent which was effective in several clinical trials and became registered for treatment of hormone receptor positive breast cancer. This article summarizes the results of published breast cancer everolimus trials. The results of two phase 3 trials are available. In the BOLERO-2 trial exemestane was compared with the combination of exemestane and everolimus, while in BOLERO-3 trial trastuzumab and vinorelbine were investigated with or without everolimus. In both trials the progression-free survival was significantly longer in the experimental arm. The overall survival data of BOLERO-2 trial, a secondary end point, are also available. The 4.4 month benefit in the experimental arm is clinically important but it has not reached the level of statistical significance. We have not had biomarkers so far that could help us to identify a subgroup of cancers sensitive to everolimus.