Abstract
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In our multicenter cohort 4 we enrolled virologically suppressed PLWHIV on an INI-based three-drug regimen with a TDF-containing backbone. Patients were then either switched to DTG +3TC (DT group) or switched from FTC/TDF to FTC/TAF while maintaining the same INI (TAF group). All patients performed dual-energy x-ray absorptiometry at time of switch [baseline (BL)] and at week 48 of follow-up; areal BMD (g/cm2) was measured at the lumbar spine (L2–L4) and at the femoral neck.
We enrolled 53 patients, 20 in the DT group and 30 in the TAF group; 35 (58%) were males, with a median age of 54 years [interquartile range (IQR) 48–63], a median time from HIV diagnosis of 17 years (IQR 7–23), and a median time of TDF exposure of 68 months (IQR 25–116). At BL, 42 patients (79%) presented a pathological BMD value: 16 (27%) had osteoporosis (8 in the DT group and 8 in the TAF group), whereas 26 (43%, 7 in DT and 19 in TAF) presented osteopenia. Full patients' characteristics are shown in Table 1. After 48 weeks of follow-up, patients in the DT group presented a significant improvement in spine BMD (+0.03 g/cm2, p = .023), as well as in spine T-score (+0.30, p = .027) and spine z-score (+0.01, p = .020). In this group we also registered an improvement in femur BMD, although not significant (+0.02 g/cm2, p = .064). In the TAF group, we recorded a significant improvement in femur BMD (+0.03 g/cm2, p = .014) and nonsignificant changes in spine BMD (−0.001 g/cm2, p = .476) after 48 weeks. In the TAF group, changes in femur BMD were significant in patients without osteoporosis (p = .028), and not in osteoporotic ones (p = .285), as well as in patients >50 years (p = .042) but not in younger patients (p = .180). Changes in spine BMD (p = .029), spine T-score (p = .035), and spine T-score (p = .013) were significantly different between groups.
Patients' Characteristics at Baseline
BMD, bone mineral density; cART, combination antiretroviral therapy; CDC, Centers for Disease Control and Prevention; DT, dual therapy; IQR, interquartile range; PI, protease inhibitor; TAF, tenofovir alafenamide fumarate; TDF, tenofovir disoproxil fumarate.
Our study suggests that switching to DTG +3TC may have a more impactful effect on BMD improvement after 48 weeks compared with a switch from TDF to TAF. To the best of our knowledge, this is the first study comparing effects on bone density of these strategies, which are both among the most prescribed regimens in treatment-experienced patients. Our study is limited by the small sample size and the retrospective observational design; nonetheless these preliminary results add to the existing literature and, with an aging HIV population, may guide clinicians in choosing the regimen most suitable to their patients' needs.
Footnotes
Author Disclosure Statement
A.C. received travel grants from ViiV Healthcare, outside the submitted study. G.G. attended advisory boards of Gilead, ViiV, and MERCK. C.M. has participated in advisory boards, received study grants and/or speaker honoraria from Abbvie, Gilead, Viiv, Janssen, Angelini, BMS, MSD. S.D.G. was a paid consultant or member of advisory boards for Gilead, ViiV Healthcare, Janssen-Cilag, Merck Sharp & Dohme, and Bristol-Myers Squibb. All other authors: none to declare.
Funding Information
This study was performed as part of our routine activity.