Table 2. Baloxavir susceptibility of zoonotic and animal influenza A viruses in MDCK-SIAT1 cells*.
| Virus subtype | FRA |
HINT |
|||
|---|---|---|---|---|---|
| No. viruses tested | EC50, nmol/L, mean ± SD† | No. viruses tested | EC50, nmol/L, mean ± SD† | ||
| Avian origin | |||||
| H5N6‡ | 3 | 0.31 ± 0.19 | – | – | |
| H6N1 | 1 | 0.12 | 1 | 0.48 | |
| H7N9 | 19 | 0.48 ± 0.32 | 9 | 1.44 ± 1.08 | |
| H9N2§ | 1 | 0.18 | 1 | 0.53 | |
| H10N8 |
1 |
0.30 |
|
1 |
0.63 |
| Swine origin | |||||
| H1N1¶ | – | – | 3 | 0.72 ± 0.27 | |
| H1N1v | – | – | 3 | 0.51 ± 0.12 | |
| H1N2v | – | – | 9 | 1.19 ± 0.36 | |
| H3N2v |
– |
– |
|
15 |
0.86 ± 0.50 |
| Reference viruses# | |||||
| A/Illinois/08/2018 (H1N1)pdm09 PA-I38 | 2.12 | – | 1.75 ± 0.59 | ||
| A/Illinois/37/2018 (H1N1)pdm09 PA-I38L |
14.96 (7-fold)** | – | 13.09 ± 3.56 (8-fold)** | ||
*Both assays were conducted by using MDCK-SIAT1 cells. Details on viruses tested are in the Appendix. According to World Health Organization nomenclature, the swine-origin influenza viruses isolated from humans are named variant viruses (e.g., A[H1N1]v). EC50, 50% effective concentration; FRA, focus reduction assay; HINT, high-content imaging neutralization test; –, not tested. †Mean ± SD or average of 2 test results. ‡One of 3 viruses was isolated from chicken (Appendix Table 1). §Virus was isolated from chicken (Appendix Table 1). ¶All 3 viruses were isolated from swine (Appendix Table 2). #A pair of seasonal influenza A(H1N1)pdm09 viruses were included in each test as reference viruses (12). **Fold change to EC50 of virus carrying PA-I38L compared with sequence-matched control virus carrying PA-I38.