CI values of three- to five-drug combinations against HIV-1 IIIB replication in MT4 cells CI < 1, = 1, and > 1 indicate synergism, additive effect, and antagonism, respectively, as described by Chou and Talalay (1984).
| Drug Combinationsa: | CI values at: | Weighted Average CI valuesb | Assigned Symbold | |||
|---|---|---|---|---|---|---|
| EC50 | EC75 | EC90 | EC95 | |||
| Three-drug combinations | ||||||
| AZT + DDC + D4T | 1.904 | 1.672 | 1.472 | 1.350 | 1.506 | – – – |
| AZT + DDC + NEV | 1.227 | 1.040 | 0.883 | 0.789 | 0.911 | ± |
| AZT + DDC + ABT-538 | 1.529 | 1.295 | 1.098 | 0.982 | 1.134 | – |
| AZT + DDI + NEV | 0.719 | 0.623 | 0.541 | 0.493 | 0.566 | + + + |
| AZT + DDI + IFN | 0.715 | 0.771 | 0.838 | 0.891 | 0.834 | + + |
| AZT + DDI + ABT-538 | 0.638 | 0.651 | 0.669 | 0.684 | 0.668 | + + + |
| AZT + D4T + NEV | 1.420 | 1.268 | 1.132 | 1.049 | 1.155 | – |
| AZT + D4T + ABT-538 | 1.335 | 1.312 | 1.290 | 1.276 | 1.293 | – – |
| AZT + IFN + NEV | 0.368 | 0.371 | 0.377 | 0.381 | 0.377 | + + + |
| AZT + IFN + ABT-538 | 0.447 | 0.494 | 0.551 | 0.597 | 0.548 | + + + |
| AZT + NEV + ABT-538 | 1.224 | 1.042 | 0.887 | 0.796 | 0.915 | ± |
| AZT + NEV + ABT-538 | 0.602 | 0.574 | 0.548 | 0.532 | 0.552 | + + + |
| DDC + D4T + NEV | 1.338 | 1.178 | 1.039 | 0.955 | 1.063 | ± |
| DDC + D4T + ABT-538 | 1.335 | 1.198 | 1.077 | 1.003 | 1.097 | ± |
| DDC + NEV + ABT-538 | 0.899 | 0.808 | 0.727 | 0.678 | 0.741 | + + |
| DDI + IFN + NEV | 0.407 | 0.475 | 0.558 | 0.625 | 0.553 | + + + |
| DDI + IFN + ABT-538 | 0.682 | 0.646 | 0.623 | 0.613 | 0.630 | + + + |
| DDI + NEV + ABT-538 | 0.687 | 0.625 | 0.573 | 0.543 | 0.583 | + + + |
| D4T + NEV + ABT-538 | 1.254 | 1.122 | 1.005 | 0.932 | 1.024 | ± |
| IFN + NEV + ABT-538 | 0.714 | 0.648 | 0.596 | 0.566 | 0.606 | + + + |
| Four-drug combinations | ||||||
| AZT + DDC + D4T + NEV | 1.390 | 1.248 | 1.120 | 1.042 | 1.141 | – |
| AZT + DDC + D4T + ABT-538 | 2.045 | 1.834 | 1.613 | 1.525 | 1.665 | – – – |
| AZT + DDC + NEV + ABT-538 | 1.340 | 1.135 | 0.967 | 0.812 | 0.976 | ± |
| AZT + DDI + IFN + NEV | 0.866 | 0.729 | 0.616 | 0.551 | 0.638 | + + + |
| AZT + DDI + IFN + ABT-538 | 0.498 | 0.488 | 0.478 | 0.479 | 0.482 | + + + |
| AZT + DDI + NEV + ABT-538 | 0.701 | 0.648 | 0.609 | 0.586 | 0.617 | + + + |
| AZT + D4T + NEV + ABT-538 | 1.756 | 1.524 | 1.322 | 1.202 | 1.358 | – – |
| AZT + IFN + NEV + ABT-538 | 0.426 | 0.420 | 0.418 | 0.416 | 0.418 | + + + |
| DDC + D4T + NEV + ABT-538 | 1.532 | 1.322 | 1.143 | 1.037 | 1.175 | – |
| DDI + IFN + NEV + ABT-538 | 0.410 | 0.388 | 0.371 | 0.364 | 0.376 | + + + |
| Five-drug combinations | ||||||
| AZT + DDC + D4T + NEV + ABT-538 | 1.440 | 1.291 | 1.149 | 1.064 | 1.173 | – |
| AZT + DDI + IFN + NEV + ABT-538 | 0.609 | 0.539 | 0.485 | 0.455 | 0.495 | + + + |
↵ a The combination ratios are designed to approximate the IC50 ratios in which the seven drugs and their corresponding constituent components have the combination ratio of AZT/DDI/DDC/IFN/D4T/NEV/ABT-538 = 1:1600:50:16:10:40:4
↵ b Because the high degrees of effects are more important to the chemotherapy than the low degrees of effects, the weighted CI value was designed as CIwt = [CI50 + 2CI75 + 3CI90 + 4CI95]/10
↵ c Degrees of synergism (+ signs) or antagonism (– signs) are based on the ranges of CI values as described in Table 4