Table 1.
ReFRAME primary and validation screen statistics for HeLa-ACE2 and Calu-3 SARS-CoV-2 infection assays.
| Assay | HeLa-ACE2/SARS-CoV-2 | Calu-3/SARS-CoV-2 | ||
|---|---|---|---|---|
| ReFRAME library screening concentration | [1.9 µM] | [9.6 µM] | Totalb | [2.5 µM] |
| Compounds screened | 11,861 | 11,861 | 11,861 | 11,861 |
| Primary hitsa | 61 | 266 | 311 | 235 |
| Average RZ′ | 0.8695 | 0.7241 | 0.7968 | 0.744 |
| Hit rate (%) | 0.51 | 2.24 | 2.75 | 1.98 |
| Tested in primary dose response (DR) | 60 | 265 | 310 | 220 |
| EC50 < 10 µM | 43 | 197 | 225 | 145 |
| Reconfirmation rate (%) | 71.7 | 74.3 | 72.6 | 65.9 |
| EC50 < 10 µM, CC50/EC50 > 10 | 15 | 53 | 58 | 42 |
| Potent and selective primary hits (%) | 25.0 | 20.0 | 18.7 | 29.0 |
| Hits tested as fresh powders | – | – | 75c | 88 |
| EC50 < 10 µM | – | – | 73 | 87 |
| EC50 < 10 µM, SI (CC50/EC50) > 10 or CC50 > max | – | – | 49 | 41 |
| Potent and selective reconfirmed hits (%) | – | – | 65.3 | 46.6 |
aPrimary hit thresholds in HeLa-ACE2: > 50% inhibition of infection, < 40% cell toxicity; 6 border-line hits included in 1.9 μM; in Calu-3: > 50% inhibition of infection, < 80% cell toxicity; 25 border-line hits included with > 40% inhibition of infection and > 40% increase in cell count (protection from virus-induced cell death).
bNon-overlapping hits from 1.9 and 9.6 μM HeLa-ACE2 screens.
c58 ReFRAME hits and 17 non-overlapping hits from pilot.