All compounds were tested at 50 µM in both assays. 300 compounds had acceptable SPR sensorgram profiles with a binding signal above 50% of the expected signal (based on the amount of protein captured on the SPR streptavidin chip), and were advanced to dose-response by SPR. Another 54 compounds that inhibited the ATPase activity by 40% or more at 50 µM were selected for SPR dose-response. Dose response measurements were conducted on the resulting 354 compounds by SPR, as well as on 96 compounds in the ATPase assay. Binding to WDR5, an unrelated protein, was also measured by SPR for selected hits to flag non-specific binders. Compounds of interest with signs of poor solubility or aggregation (<80% detected laser power at 100 µM) as measured by dynamic light scattering (DLS) were also flagged but were not dismissed to avoid false negatives (Table ). Indeed, unlike a typical drug discovery program, no active compound should be left behind in CACHE, as this would defeat the purpose of evaluating the efficiency of computational predictions. In the end, 46 compounds selected by 18 teams had a K D < 150 µM, a binding signal between 30% and 150% of the expected signal, and were advanced to Round 2 (Figure , Table ). While most hit rates were between 0 and 3%, workflows WF1454, WF1418 and WF1456 had significantly higher hit rates (9%, 8% and 7% respectively). The overall Round 1 hit rate was 2.3%.