From genomic data analysis to drug development: a new generation of trials using molecular marker assessment in breast cancer

With the advent of molecular subtypes in breast cancer, the landscape of clinical trials and drug development is rapidly changing. Molecular screening identifies numerous mutations but actually druggable targets are few and far between. Thus, new clinical trial concepts are needed which are feasible in clinical practice and successful from the point of view of drug development. This article highlights the evolution of the sequencing technologies, the current molecular screening efforts and their impact on drug development as well as novel successful trial designs, focusing on the hormone receptor (HR) positive breast cancer patients. The range of mutations to identify in order to adapt the treatment to each patient and limit the resistance mechanisms is quite wide already, but theoretical or practical restriction may have to be considered to optimize the development of such adaptive combinations of targeted therapies.