Study group (n) | Study drug | Estimated TAF implant daily drug release rate (mg/day) | Insertion site or oral | Duration of study drug exposure* |
Group 1 (n=6) | ||||
1 (6) | TAF 110 mg implant | 0.25 | Arm | Up to 28 days |
Group 2 (n=30) | ||||
2a (12) | TAF 110 mg implant | 0.25 | Arm | Approximately 24–48 weeks |
2b (3) | Placebo implant | 0 | Arm | Approximately 24–48 weeks |
2c (12) | 2 TAF 110 mg implants | 0.50 mg | One arm | Approximately 24–48 weeks |
2d (3) | 2 placebo implants | 0 | One arm | Approximately 24–48 weeks |
Group 3 (n=24) | ||||
3a (6) | 2 TAF 110 mg implants | 0.50 | One implant per arm | Up to 24 weeks |
3b (6) | 3 TAF 110 mg implants | 0.75 | One arm | Approximately 24–48 weeks |
3c (6) | TAF 25 mg tablet | 25 | Oral | Up to 24 weeks |
3d (6) | 4 TAF 110 mg implants | 1.0 | One arm | Approximately 24–48 weeks |
Group 4 (n=490) | ||||
4a (245) | TAF implant(s) plus placebo oral tablet | 0.50 mg† | †Two TAF implants per arm plus oral placebo tablets | Approximately 48–120 weeks |
4b (245) | TDF 300mg/FTC 200 mg oral tablet+placebo implant/s | 0 | †Two placebo implants per arm plus oral TDF/FTC tablets | Approximately 48–120 weeks |
*Follow-up extended based on safety review of the adverse events occurring during the first 4 weeks after insertion in Groups 1–3.
†Based on the PK and safety assessment in dog models but is subject to change after PK data become available from Groups 1–3 in the trial.
FTC, emtricitabine; TAF, tenofovir alafenamide fumarate; TDF, tenofovir disoproxil fumarate.