TABLE 4.
Selection by pibrentasvir of amino acid substitutions in NS5A from HCV genotypes 1 to 6
| HCV genotypea | Colony survival (%)b |
NS5A amino acid substitution(s) | Prevalence in replicon selectionc |
Mean EC50 ± SD (pM) | Fold change in EC50d | Replication efficiency (%)d | ||
|---|---|---|---|---|---|---|---|---|
| 10× EC50 | 100× EC50 | 10× EC50 | 100× EC50 | |||||
| 1ae | 0.0065 | 0.0002 | Q30Df | 0/20 | 1/4g | 68 ± 37 | 94 | 50 |
| Q30 deletion | 0/20 | 1/4g | 2,555 ± 268 | 3,549 | 0.5 | |||
| Y93D | 0/20 | 1/4g | NVj | NV | <0.5 | |||
| Y93H | 18/20 | 0/4g | 4.8 ± 1.5 | 6.7 | 18 | |||
| Y93N | 1/20 | 0/4g | 5.1 ± 2.1 | 7.1 | 25 | |||
| H58D Y93H | 0/20 | 1/4g | 1,612 ± 272 | 2,238 | 13 | |||
| 1b | 0 | ND | NA | NAi | NA | NA | NA | |
| 2ae | 0.00015 | 0 | F28S M31I | 2/3g | NA | 14,303 ± 2,722 | 14,448 | |
| P29S K30G | 1/3g | NA | 2.3 ± 0.36 | 2.3 | ||||
| 2b | 0 | 0 | NA | NA | NA | NA | NA | |
| 3ae | 0.0003 | 0 | Y93H | 3/3h | NA | 1.5 ± 0.19 | 2.3 | |
| 4a | 0 | 0 | NA | NA | NA | NA | NA | |
| 5a | 0 | 0 | NA | NA | NA | NA | NA | |
| 6a | 0 | 0 | NA | NA | NA | NA | NA | |
Genotype of NS5A in replicon cell lines.
Calculated as follows: (number of surviving colonies/number of input replicon cells) × 100. ND, not determined; EC50, pibrentasvir 50% effective concentration.
Number of times an amino acid substitution was found/the total number of colonies analyzed.
Relative to the respective wild-type replicon.
Pibrentasvir EC50s for wild-type replicons in transient-transfection assays were as follows: genotype 1a, 0.72 pM; genotype 2a, 0.99 pM; genotype 3a, 0.65 pM.
Substitution with double nucleotide changes.
Denominator indicates the total number of colonies that survived selection out of 2 × 106 input cells.
Denominator indicates the total number of colonies that survived selection out of 1 × 106 input cells.
NA, not applicable.
NV, not available as the EC50 could not be determined due to low replication efficiency of the replicon containing the amino acid substitution.