Table 1.
Summary of patient characteristics and HBV sequence data generated from three South African adults. All patients had with persistent HBV viraemia ≥20,000 IU/mL despite >12 months prescription of TDF therapy.
| Patient ID | 209 | 258 | 289 |
|---|---|---|---|
| Treatment | TDF + 3TC + FTC | TDF + 3TC + FTC | TDF |
| Age range at recruitment | 41−50 | 41−50 | 61−70 |
| HIV status | Positive | Positive | Negative |
| Elastography score (kPa) | 6.9 | 5.1 | 9.1 |
| HBV DNA viral load, log10 IU/mL at time of sequencing | 8.03 | 6.77 | 8.18 |
| HIV RNA viral load, log10 copies/mL at time of sequencing | 1.74 | 4.97 | N/A |
| Median coverage/site | 4262 | 1601 | 14 |
| HBV Genotype | A | D | A |
| Reverse transcriptase (RT) polymorphisms potentially associated with TDF resistance | Y9H | Y9H | Y9H |
| L91I | F122L | L91I | |
| H126Y | S223A | H126Y | |
| R153W* | D263E | S223A | |
| V173L*, † | V278I | C256S | |
| L180M*, † | A317S | ||
| M204V*, † | |||
| S223A | |||
| C256S |
Underlined polymorphisms have been reported as RAMs, but occur frequently in the genotype identified in this patient (see Table 2).
*
These RAMs have been identified based on a combination of both in vivo and in vitro data and are reported in ≥2 independent peer-reviewed sources, giving them the most stringent evidence base of all the polymorphisms listed [6].
†
These RAMs cause HBV resistance to 3TC [8]. As patient 209 was on both TDF and 3TC, it is likely that exposure to 3TC resulted in the selection of RAMs V173L, L180M and M204V.