TABLE 4.
Combination indices for BI 201335-IFN-α and BI 201335-ribavirin drug combinations
| Drug combination and ratio | Combination index (95% confidence interval) |
||
|---|---|---|---|
| 50% inhibition | 75% inhibition | 90% inhibition | |
| BI 201335/IFN-α ratioa | |||
| 1:6 | 1.00 (0.68-1.30) | 1.09 (0.74-1.41) | 1.21 (0.82-1.57) |
| 1:12 | 0.99 (0.83-1.10) | 0.95 (0.80-1.05) | 0.94 (0.79-1.05) |
| 1:60 | 1.38 (1.22-1.54) | 1.00 (0.89-1.12) | 0.81 (0.72-0.90) |
| 1:300 | 1.53 (0.98-2.44) | 1.13 (0.72-1.80) | 0.94 (0.60-1.49) |
| 1:600 | 1.34 (1.14-1.67) | 0.95 (0.81-1.18) | 0.73 (0.62-0.91) |
| BI 201335/ribavirin ratiob | |||
| 1:220 | 0.99 (0.77-1.29) | 1.11 (0.86-1.44) | NDc |
| 1:440 | 1.14 (0.88-1.53) | 1.09 (0.84-1.46) | ND |
| 1:2,200 | 1.21 (0.99-1.52) | 0.98 (0.80-1.23) | ND |
| 1:11,000 | 0.93 (0.73-1.14) | 0.90 (0.70-1.10) | ND |
| 1:22,000 | 0.83 (0.58-1.07) | 0.97 (0.68-1.25) | ND |
a
The BI 201335/IFN-α ratio shows the ratio of BI 201335 concentration (micromolar) to alpha interferon (IFN-α) (in international units per millililiter). The 1:60 ratio corresponds to equipotent concentrations of the two drugs.
b
The BI 201335/ribavirin ratio is a molar ratio. The 1:2,200 ratio corresponds to equipotent concentrations of the two drugs.
c
ND, not determined due to cytotoxicity observed at the required concentrations of ribavirin.