TABLE 5.
Simultaneous determination of resistance to HIV-1 PR and RT inhibitors by recombinant viruses with plasma-derived sequences encoding PR and RTa
| Drug | IC50 (μM) (fold resistanceb)
|
||||
|---|---|---|---|---|---|
| Sample 1 | Sample 2 | Sample 3 | Sample 4 | Sample 5 | |
| AZT | 0.32 (5) | 66.6 (998) | 5.60 (57) | 73.6 (460) | 31.9 (426) |
| 3TC | 7.77 (1) | 35.7 (5) | >100 (>13) | >100 (>11) | 18.42 (4) |
| ddI | 2.34 (1) | 10.1 (1) | 12.4 (2) | 1.98 (1) | 7.62 (1) |
| ddC | 1.94 (1) | 3.52 (1) | 9.75 (3) | 9.21 (3) | 2.06 (1) |
| d4T | 1.95 (1) | 7.68 (1) | 7.21 (1) | 7.73 (2) | 7.15 (4) |
| Loviride | 0.047 (1) | 0.09 (1) | 3.49 (46) | 0.02 (1) | >100 (>1700) |
| Nevirapine | ND | 0.32 (2) | 94.7 (622) | ND | >100 (>758) |
| Indinavir | 0.023 (3) | 0.11 (7) | 0.39 (21) | 0.63 (8) | 1.95 (104) |
| Saquinavir | 0.046 (15) | 0.003 (1) | 0.05 (8) | 0.36 (37) | 3.50 (579) |
| Ritonavir | 0.092 (4) | 1.15 (23) | 7.71 (120) | 1.71 (20) | 11.3 (175) |
| Viral loadc | 26,000 | 191,000 | 269,000 | 400,000 | NA |
| CD4 count | 224 | 75 | 54 | 314 | NA |
The combined PR-RT resistance pattern (10 drugs) was determined for different samples. The results for five samples with different patterns of resistance to all inhibitors are presented. Resistance to nevirapine was not determined (ND) for samples 1 and 4. Results are expressed as IC50s and fold resistance. Viral load data and CD4 count (numbers of cells per milliliter) were not available (NA) for sample 5.
Fold-increase in the mean IC50 relative to the mean IC50 for the wild type. The mean IC50s for both patient and wild-type viruses were derived from two to four separate susceptibility determinations by the MT4-MTT assay.
Number of HIV-1 RNA copies per milliliter of plasma as determined by the Roche Amplicor HIV-1 Monitor assay.