Table 2.
Computer-simulated combination index (CI) of two-drug combinations at 50, 75, 90, and 95% inhibition of HBV replication in HepAD38 cellsa
| Drug combination | Ratio | CI at inhibition of: |
CIwt | |||
|---|---|---|---|---|---|---|
| 50% | 75% | 90% | 95% | |||
| TDF + (−)-FTC | 1:1 | 0.9 | 0.8 | 0.7 | 0.7 | 0.7 |
| TDF + (−)-FTC | 1:2 | 0.9 | 0.8 | 0.8 | 0.8 | 0.8 |
| TDF + (−)-FTC | 1:5 | 10.0 | 7.3 | 5.4 | 4.4 | 5.8 |
| TDF + (−)-FTC | 1:10 | 12.2 | 9.7 | 7.7 | 6.6 | 8.1 |
| TFV + (−)-FTC | 1:1 | 1.1 | 0.9 | 0.7 | 0.6 | 0.7 |
| TFV + (−)-FTC | 2:1 | 3.3 | 3.3 | 3.3 | 3.4 | 3.3 |
| TFV + (−)-FTC | 5:1 | 15 | 11 | 7.8 | 6.2 | 8.5 |
a
CI values were determined for a mutually exclusive interaction using the CalcuSyn program; a CI of <1, 1, or >1 indicates synergism, an additive effect, and antagonism, respectively. CIwt, weighted-average CI, which was assigned as (CI50 + 2CI75 + 3CI90 + 4CI95)/10, where CI50, CI75, CI90, and CI95 represent CIs for 50, 75, 90, and 95% inhibition, respectively (10).