Effectiveness and safety of tenofovir alafenamide fumarate-based therapy compared to tenofovir disoproxil fumarate- and abacavir-based therapy in children and young people living with HIV in Europe.

Objective: Effectiveness and safety outcomes were compared between those on tenofovir alafenamide fumarate (TAF), tenofovir disoproxil fumarate (TDF) or abacavir (ABC), among children and young people living with HIV (CYPLHIV) aged 6-<25 years.

Results: 577 CYPLHIV received TAF, 428 TDF and 426 ABC. 96%/83%/55% were ART-experienced, median age at drug start was 15·8/14·6/12·5 years, and median duration of follow-up was 1·6/2·3/3·0 years, respectively. Among all ART-experienced CYPLHIV at drug start there was no difference in the proportion virologically suppressed at 48 weeks. However, in those suppressed at drug start, the proportion suppressed at 48 weeks was higher on TDF than TAF (p=0·008). There was no difference in time to suppression (amongst unsuppressed at start) or to viral failure. Among those on TAF, there were four serious adverse events, of which 1 (renal colic) was considered related to TAF and led to discontinuation. The rate of treatment-emergent grade≥1 laboratory events was highest on TAF (adjusted incidence rate ratio vs. TAF: TDF 0·74(0·56-0·99, p=0·046); ABC 0·69(0·53-0·88), p=0·004). Rates of grade≥1 LDL and total cholesterol events on TAF were comparable on ABC, but higher than TDF, with no difference in bone/renal markers. There was no significant difference in grade≥3 events (p>0·500), although numbers were small. The risk of discontinuation (for reasons other than optimisation/simplification/unknown reason) was lowest for TAF.

Conclusion: Virological outcomes were similar across drugs. Rates of any grade laboratory events were highest on TAF, driven by higher rates of lipid events. As TAF uptake increases, studies with long-term follow-up are required.