Switch From Tenofovir to Raltegravir for Low Bone Mineral Density (TROP)

Inclusion Criteria:

1. provision of written, informed consent
2. HIV-infected adults at least 18 years of age
3. receiving stable ART including TDF and a r/PI for the previous 6 months
4. no prior PI genotypic resistance or known replication of HIV in patients receiving a PI
5. plasma HIV RNA < 50 copies/ml for at least the previous 3 months

6. spine or neck of femur t-score ≤ -1.0 (i.e. WHO-defined osteopenia) measured by dual energy x-ray absorptiometry (DEXA)

   Exclusion Criteria:

7. participation in any other clinical trial (unless approved by the study PI)
8. use of TDF for previously active chronic hepatitis B infection
9. receiving or requiring therapy for low BMD (including prior fragility fracture)
10. using oral corticosteroids or inhaled fluticasone
11. virological failure on, or intolerance to, RAL
12. contra-indication to RAL therapy (see appendix 2)
13. breast-feeding
14. pregnancy
15. secondary, endocrinological cause of low BMD:25-hydroxy vitamin D deficiency, hypogonadism: a)symptomatic b)asymptomatic defined by total testosterone > 25% below lower limit of reference range and/or luteinizing hormone > 2 x upper limit of normal (ULN),untreated hypothyroidism or hyperparathyroidism according to local reference ranges