Table 3.
Antiviral activity of GRL-04810 and GRL-05010 against laboratory PI-resistant HIV-1 variants and GRL-04810- and GRL-05010-exposed HIV-1 variants
| Virusa | EC50 (μM)b |
||||||
|---|---|---|---|---|---|---|---|
| SQV | LPV | ATV | APV | DRV | GRL-04810 | GRL-05010 | |
| HIV-1NL4-3 | 0.037 ± 0.002 | 0.035 ± 0.005 | 0.0047 ± 0.0001 | 0.081 ± 0.001 | 0.004 ± 0.001 | 0.0005 ± 0.0005 | 0.0037 ± 0.0001 |
| HIV-1SQVR5μM | >1 (>25) | >1 (>25) | >1 (>250) | 0.435 (5) ± 0.001 | 0.04 (10) ± 0.01 | 0.13 (260) ± 0.05 | 0.046 (13) ± 0.001 |
| HIV-1LPVR5μM | 0.025 (1) ± 0.005 | >1 (>25) | 0.033 (8) ± 0.001 | 0.033 (1) ± 0.005 | 0.032 (8) ± 0.001 | 0.03 (66) ± 0.01 | 0.03 (8) ± 0.02 |
| HIV-1ATVR5μM | 0.46 (12) ± 0.02 | >1 (>25) | > 1 (>250) | >1 (>13) | 0.05 (13) ± 0.01 | 0.02 (36) ± 0.01 | 0.04 (12) ± 0.02 |
| HIV-1APVR5μM | 0.09 (2) ± 0.04 | >1 (>25) | 0.66 ± 0.02 | >1 (>13) | 0.51 (128) ± 0.03 | 0.43 (860) ± 0.02 | 0.56 (187) ± 0.03 |
| HIV-1GRL04810RP18 | 0.032 (1) ± 0.005 | 0.37 (11) ± 0.02 | 0.325 (81) ± 0.004 | >1 (>13) | 0.041 (11) ± 0.001 | 0.033 (66) ± 0.003 | 0.039 (13) ± 0.005 |
| HIV-1GRL05010RP10 | 0.036 (1) ± 0.003 | 0.375 (11) ± 0.005 | 0.095 (24) ± 0.035 | >1 (>13) | 0.037 (10) ± 0.003 | 0.029 (58) ± 0.001 | 0.036 (10) ± 0.001 |
The amino acid substitutions identified in the protease-encoding region compared to the wild-type HIV-1NL4-3 include L10F, V32I, M46I, I54M, A71V, and I84V in HIV-1APVR5μM; L23I, E34Q, K43I, M46I, I50L, G51A, L63P, A71V, V82A, and T91A in HIV-1ATVR5μM; L10F, M46I, I54V, and V82A in HIV-1LPVR5μM; and L10I, G48V, I54V, A71V, I84V, and L90M in HIV-1SQVR5μM.
MT-4 cells (105/ml) were exposed to 100 TCID50 of each HIV-1, and the inhibition of p24 Gag protein production by each drug was used as an endpoint. The numbers in parentheses represent the fold changes of EC50s for each isolate compared to the EC50s for wild-type HIV-1NL4-3. All assays were conducted in duplicate or triplicate, and the data shown represent mean values (± 1 standard deviation) derived from the results of two or three independent experiments. In addition, GRL-04810- and GRL-05010-resistant variants selected in vitro were used for antiviral activity determination assays. Time point viruses were harvested at passages 18 and 10, respectively. Washing steps were performed to remove the remaining compounds from the viral stocks, and compound-free viruses were obtained for the experiment. Five commercially available protease inhibitors were used as controls. Absolute values are given plus the fold changes relative to the baseline EC50 for each compound. By passage 18, three amino acid substitutions A28S, L33F, and V82I were identified in HIV-1GRL04810RP18; by passage 10, M46I, I50V, N38K, and M36I were detected in HIV-1GRL05010RP10. Assays were performed in duplicate and the average values (with 1 standard deviation) are shown.