Predicting drug sensitivity profiles from genotypes is a major challenge in personalized medicine. Machine learning and deep neural network methods have shown promise in addressing this challenge, but the "black-box" nature of these methods precludes a mechanistic understanding of how and which genomic and proteomic features contribute to the observed drug sensitivity profiles. Here we provide a combination of statistical and neural network framework that not only estimates drug IC 50 in cancer cell lines with high accuracy (R 2 = 0.861 and RMSE = 0.818) but also identifies features contributing to the accuracy, thereby enhancing explainability. Our framework, termed QSMART, uses a multi-component approach that includes (1) collecting drug fingerprints, cancer cell line's multi-omics features, and drug responses, (2) testing the statistical significance of interaction terms, (3) selecting features by Lasso with Bayesian information criterion, and (4) using neural networks to predict drug response. We evaluate the contribution of each of these components and use a case study to explain the biological relevance of several selected features to protein kinase inhibitor response in non-small cell lung cancer cells. Specifically, we illustrate how interaction terms that capture associations between drugs and mutant kinases quantitatively contribute to the response of two EGFR inhibitors (afatinib and lapatinib) in non-small cell lung cancer cells. Although we have tested QSMART on protein kinase inhibitors, it can be extended across the proteome to investigate the complex relationships connecting genotypes and drug sensitivity profiles. Introduction 1 Protein kinases are a class of signaling proteins, greatly valued as therapeutic targets for 2 their key roles in human diseases, such as cancer [1]. For decades, chemotherapy has 3 served as part of a standard set of cancer treatments; however, the resistance of cancer 4 cells to chemotherapy is still a major clinical challenge [2]. Mutations in protein kinase 5 are known to play important roles not only in drug resistance [3] but also in drug 6 sensitivity [4]. Depending on the structural location, mutations can have varying 7 impacts on drug sensitivity. For example, non-small cell lung cancer (NSCLC) cells 8 December 28, 2019 1/25 harboring either the EGFR T790M or L858R mutation respectively leads to resistance 9 or hypersensitivity to the cancer drug gefitinib [5, 6], while those with EGFR 10 T790M/L858R double mutant are only resistant to gefitinib [7]. As mutations impact 11 the efficacy of different cancer drugs, there is a need to incorporate structural 12 knowledge in drug response prediction methods. 13 To facilitate the understanding of the molecular mechanisms that cause drug 14 sensitivity and drug resistance in cancer cells, the Genomics of Drug Sensitivity in 15 Cancer (GDSC) Project [8] recently screened the drug responses of 266 anti-cancer 16 drugs against âŒ1,000 human cancer cell lines and provided the largest publicly available 17 drug response datas...