Predicting Quantifiability from Primary Screens to Prioritize Dose-Response Profiling
Organizations: Department of Natural Science, Rice University, Houston, TX, USA
Abstract
High-throughput drug screening relies on low-cost primary assays to prioritize compounds for more expensive dose-response profiling, where potency is ultimately quantified. Current screening strategies largely focus on identifying compounds that will confirm biological activity on follow-up, implicitly assuming that confirmed activity will also yield a usable potency estimate. However, confirmed biological activity in screening does not necessarily translate into a quantifiable potency, because active compounds can still fail to produce a reportable dose-response estimate. We therefore present a framework for modeling quantifiability, whether follow-up testing will yield a usable potency estimate, as a distinct triage objective from biological activity. Quantifiability was strongly predictable from the preceding low-cost screen, with most predictive information arising from the observed screening features rather than molecular structure. Response-based predictors remained robust on previously unseen chemical scaffolds and generalized across held-out assay-mechanism families, while the probability of successful quantification varied strongly with response amplitude and assay context. These findings establish experimental measurability, distinct from biological activity, as a predictable property of screening outcomes and show that quantifiability-aware triage can improve the allocation of costly dose-response profiling capacity.
Figures & tables
| Policy | AUROC | AUPRC | Recall@50% | Yield@25% |
|---|---|---|---|---|
| Random | ||||
| Random forest (fingerprints only) | ||||
| Maximum three-point activity | ||||
| Random forest (three-point only) | ||||
| Mean three-point activity | ||||
| Logistic regression (full features) |
| Feature set | Contents | AUROC | AUPRC | Rec@50% | AUROC | |
| Isolated blocks (five-fold) | ||||||
| Three-point only | 3pt block | 16 | — | |||
| Fingerprints only | Morgan bits | 1,024 | — | |||
| Full model | all blocks | 1,074 | — | |||
| Nested addition (three-fold) | ||||||
| Three-point only | 3pt block | 16 | — | — | — | |
| Mechanism family | active | Quantifiable | Unquantifiable | Failure (%) |
|---|---|---|---|---|
| G-protein activation | 6,824 | 5,542 | 1,282 | 18.8 |
| Competition binding | 4,199 | 3,038 | 1,161 | 27.6 |
| Barr2 recruitment | 8,375 | 5,394 | 2,981 | 35.6 |
| Co-factor recruitment | 890 | 489 | 401 | 45.1 |
| Heterodimer | 1,134 | 209 | 925 | 81.6 |
| All active pairs | 21,422 | 14,672 | 6,750 | 31.5 |
| Subgroup | Pos. (%) | AUROC | Rec@50% | |
|---|---|---|---|---|
| Target class | ||||
| Kinase (competition binding) | 1,547 | 37.8 | 0.975 | 0.974 |
| Nuclear receptor | 704 | 19.9 | 0.944 | 0.964 |
| 7TM | 4,344 | 50.9 | 0.920 | 0.828 |
| Screening category | ||||
| Compound of interest | 2,710 | 73.5 | 0.923 | 0.665 |
| Release | Test | Quantifiable | Pos. (%) | AUROC | Rec@50% (model) | Rec@50% (screening) |
|---|---|---|---|---|---|---|
| 4 | 4,731 | 1,966 | 41.6 | 0.814 | 0.785 | 0.751 |
| 5.1 | 4,462 | 1,851 | 41.5 | 0.867 | 0.832 | 0.774 |
| 6 | 2,739 | 1,297 | 47.4 | 0.918 | 0.865 | 0.850 |
| 7 | 2,722 | 1,079 | 39.6 | 0.944 | 0.943 | 0.902 |
| 8 | 2,475 | 805 | 32.5 | 0.977 | 0.985 | 0.974 |
| 9 | 3,571 | 2,077 | 58.2 | 0.885 | 0.748 | 0.703 |