Weight gain on 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: To compare BMI-for-age z-score (zBMI) changes in treatment-experienced children and young people living with HIV aged 6 to <25 years on tenofovir alafenamide fumarate (TAF) to those on tenofovir disoproxil fumarate (TDF) and abacavir (ABC).

METHODS: Cohort study of children and young people living with HIV from 12 European countries were grouped by drug exposure: 1 - on TAF with prior TDF use; 2 - on TAF no prior TDF; 3 - on TDF; and 4 - on ABC. Outcomes, adjusted for characteristics at drug start, were (i) incidence of overweight or obesity by 96 weeks, (ii) zBMI change 48 weeks before/after drug start, (iii) association between TAF/TDF/ABC and anchor drug on zBMI change and (iv) factors associated with zBMI change on TAF over 96 weeks.

RESULTS: Overall, 162, 189, 270 and 144 were in groups 1, 2, 3 and 4, respectively. Median ages at drug start were 16, 13, 14 and 12 years. Obesity incidence by 96 weeks was 16%, 13%, 6% and 12% and higher on TAF than TDF (p = 0.018) but comparable to ABC (p = 0.568). Similar trends were seen for overweight/obesity, although differences were not significant. Over 48 weeks, zBMI increased at a higher rate on TAF than TDF (p = 0.001) but similar to ABC (p = 0.652). zBMI change was higher after than before drug start in group 1 (p = 0.059) but similar in other groups. Over 96 weeks zBMI change on TAF/TDF/ABC combined with dolutegravir vs. other anchor drugs was not statistically different (p = 0.196). zBMI change on TAF varied by age (p = 0.001), prior TDF (p = 0.019), viral load (p = 0.042) and zBMI (p = 0.004) at TAF start.

CONCLUSION: zBMI increased on TAF, faster than TDF, but similar to ABC. Weight gain on TAF was associated with multiple factors including prior TDF use.