To improve the effectiveness of cancer drug combination therapy, accounting for intratumor heterogeneity is critical, particularly as the tumor evolves under exposure to different drug regimes.  We aim to identify optimal cancer drug combinations based on the single cell characterization of an individual tumor response to a panel of monotherapies.  Using state-of-the-art single cell technology, namely mass cytometry, we quantify changes in the expression of intracellular markers  before and after treatment for approximately 30 markers per cell under each drug.  We discuss methods to integrate this data in order to identify and compare the drug combination strategies that are optimized under a variety of objective functions.  This strategy for optimizing drug combinations can complement genomics based strategies for a more comprehensive approach to personalized treatment.