Tenofovir disoproxil

The percentage of participants with HBV DNA \< 400 copies/mL at Week 72 was summarized by treatment and age group (grouped by baseline age for analysis), using the missing = failure (M = F) analysis with the double-blind efficacy evaluation (DBEE) algorithm. In the M = F analysis method, all missing data were considered as failure to meet the outcome measure threshold. This method was combined with the DBEE algorithm, which included all available data for the double-blind period, and any data for the open-label period were not included; data generated during treatment-free follow-up from subjects who achieved HBsAg loss and entered treatment-free follow-up during double-blind treatment period were included.

Data were summarized by treatment and age group (grouped by baseline age for analysis). In contrast with what was previously reported in the interim results posting, 1 participant met the primary safety endpoint of at least a 6% decrease from baseline in spine BMD at Week 72, based on the final BMD data analysis. The apparent discrepancy was due to the correction factor applied to the subject-specific BMD calculations performed at the time of the Interim Week 72 clinical study report that could not take into account the actual Week 72 phantom data (ie, calibration test used in longitudinal clinical trials to monitor and adjust for shifts in the dual-energy x-ray absorptiometry (DXA) scanner calibration over time), which were not provided by the site at that time. The correction factor applied to the final analysis has been properly based on all phantom data through the end of Week 72, as well as through the end of Week 192.

Study visits were scheduled every 30 days until completion of the study, and participants were instructed to return to the clinic for evaluation in the event of an illness. Participants reported any adverse effects at monthly visits and interim visits.

Study visits were scheduled every 30 days until completion of the study and during monthly study visits, we performed testing for HIV infection. At completion of the study, we tested all participants for HIV infection, using an enzyme-linked immunosorbent assay (ELISA).The primary efficacy end point was the difference in the rates of HIV infection between participants assigned to receive TDF-FTC and those assigned to receive placebo. The initial efficacy analysis included all study participants who were randomly assigned to receive a study medication (intention-to-treat cohort).

The change from baseline to Week 24 in HBsAg was analyzed using a mixed effect model for repeated measures (MMRM). The model included treatment groups, ALT levels (\> ULN or ≤ ULN) at baseline, HBeAg status (positive or negative) at baseline, HBsAg level at baseline, visit and treatment-by-visit interaction as fixed effects and visit as a repeated measurement. Estimated least square means of treatment effects are presented with the 95% confidence intervals (CIs).

Tolerability failure was defined as permanent discontinuation of study drug due to a treatment-emergent adverse event (AE), including any subject who temporarily discontinued study drug due to an AE and did not restart. Results are expressed as proportions of participants who experience tolerability failure using the Kaplan-Meier (KM) method of estimation.

Results are expressed as proportions of participants who experience a confirmed increase in serum creatinine of ≥ 0.5 mg/dL from baseline or a confirmed serum phosphorus level \< 2.0 mg/dL using the KM method of estimation.