Introduction: The management of complex interactions between antiretroviral therapy (ART) and calcineurin inhibitor (CNI) immunosuppression regimens in HIV+ to HIV+ renal transplant recipients can be challenging. Literature describing ART regimens and indications for regimen switching in these patients is limited. 
Methods: This retrospective review included 53 HIV+ to HIV+ renal transplant recipients. Data on ART regimens, reasons for ART switching and timing of switches were described from day of transplant to study endpoint (end of study date, death or graft failure). The association between rejection and ART regimen (protease inhibitor (PI) based versus non-PI based regimen) was analysed using negative binomial regression. 
Results: There were a total of 46 switches in 31/53 patients (58%). Protocol switches (n=17/46, 37%) accounted for most switches, of which the majority were from non-nucleoside reverse transcriptase inhibitors (NNRTIs) to PIs. Other common reasons for switching include cytochrome P450 enzyme induction from efavirenz (EFV) (9/46, 20%), tenofovir disoproxil fumarate (TDF) nephrotoxicity (8/46, 17%) or side effects (6/46, 13%). Of the 46 switches, nearly half (n=21, 46%) occurred during the transplant admission period, and around two thirds (n=28, 62%) were in the first year post transplant. There was an association between rejection and being maintained on a PI-based regimen (IRR 2.77 (95% CI 1.03-7.48), p=0.044). 
Conclusion: Despite frequent switching of ART regimens, HIV viral loads remained supressed and graft function remained stable in most HIV-positive kidney transplant recipients in our cohort. There was however a concerning signal for increased rejection rates in those on a PI-based regimen.