Identification of KIs currently licensed or in trial that overcome resistance to venetoclax in 2S-stimulated cells from individual patients. Heatmaps of (A) total cytotoxicity expressed as percentage positive (classified similarity to STS + venetoclax control) and (B) venetoclax-enhanced cytotoxicity expressed as an increase in percentage positive for 2S-stimulated CLL cells from 13 patients incubated with KIs that are licensed or in clinical trials (1 μM) in combination with venetoclax (10 nM), as indicated. Rows indicate individual KIs; columns indicate different patient samples. The grayscale bar shows percentage of cells classified as positive as indicated at the bottom in panel A, and the color bar indicates venetoclax-enhanced percentage positive in panel B. A combination of KI and venetoclax is considered to be effective if venetoclax increases the percentage-positive classification by >25% above the value for KI alone, corresponding to a mean total kill of 63% in screen positives (yellow [B]). A combination of KI and venetoclax was considered to be highly effective if addition of venetoclax increased the amount of cell death by >45% (red [B]), corresponding to a total kill of >80% for the drug combination (A). The controls below the heatmaps show percentage-positive cells for the negative control (DMSO) and venetoclax alone in panel A, and venetoclax-enhanced percentage-positive cells compared with DMSO (ie, the difference between venetoclax and DMSO alone) in panel B, for individual patients. The columns are sorted in decreasing order of venetoclax-enhanced percentage-positive compared with DMSO; rows are ranked according to frequency of effective KI-venetoclax combinations. For combinations with the same frequency, the rows were further sorted based on the average value for venetoclax-enhanced effect across positive screens. Results are shown for 62 of the 320 KIs (results for all KIs are in supplemental Figure 2). Sunitinib (★) was identified for further analysis as the licensed compound with a high frequency (8 of 13 patient samples) and degree of venetoclax-enhanced kill (mean value of 45% enhanced kill in screen positives). The arrow and arrowhead refer to dasatinib and alvocidib, respectively (see “Discussion” for more details). Patient samples were analyzed by fluorescence-based high-content screening for percentage positive as described in Figure 2. The 10 nM dose of venetoclax was selected for screening as it was the highest concentration that exhibited minimal activity against 2S-stimulated CLL cells (Figure 2B-C).