Noopur Raje, MD from the Massachusetts General Hospital, Boston, MA discusses highlights of the in vivo drug screening session in multiple myeloma (MM) held at the Myeloma 2016 meeting in Boston, MA with Constantine Mitsiades, MD, PhD from the Dana-Farber Cancer Institute, Boston, MA and Caroline Heckman, PhD from the University of Helsinki, Helsinki, Finland. Dr Heckman provides an overview of her talk on stratifying myeloma by in vivo drug response. According to Dr Heckman, it is important to work with real patient samples as the disease is very heterogeneous. With a high throughput screening assay it is possible to do a functional assessment of the sensitivity of the patients’ cells to particular drugs, which usually are small molecule inhibitors. Based on the results, it is possible to assess whether the drugs might be useful for the patient, which is key as more drugs are being developed. The same approach can also be applied to combinations according to Dr Heckman. Dr Mitsiades provides an overview the CRISPR technology to silence genes and its utility in MM, such as identifying common targets in subsets of patients. Dr Raje highlights the importance of being able to decide which drugs to use for which patients and they further discuss the microenvironment in the context of these new techniques.