Long-term efficacy and safety of rilpivirine plus abacavir and lamivudine in HIV-1 infected patients with undetectable viral load

<div><p>Introduction</p><p>A regimen with rilpivirine (RPV), abacavir (ABC) and lamivudine (3TC) is simple and may allow the sparing of tenofovir and protease inhibitors. However, data on use of this combination as a strategy of switch are limited. Aims of the study were to assess the long-term efficacy and safety of this regimen.</p><p>Methods</p><p>Retrospective study on HIV-1 infected patients followed at the Infectious Disease Department of the San Raffaele Scientific Institute, HBsAg-negative, HLA B5701-negative, with no documented resistance to RPV, ABC and 3TC, with HIV-RNA<50 copies/mL who started RPV plus ABC/3TC from March 2013 to September 2015.</p><p>The primary outcome was durability [no treatment failure (TF)]. Secondary objectives were to evaluate changes in immunological, metabolic and other safety parameters.</p><p>TF was defined as the occurrence of virological failure (VF, 2 consecutive values >50 copies/mL) or discontinuation of any drug in the regimen for any reason.</p><p>Patients’ follow-up accrued from the date of RPV plus ABC/3TC initiation to the date of TF (VF or discontinuation of any drug in the regimen) or to the date of last available visit.</p><p>Time to TF was evaluated by use of the Kaplan-Meier curves. Mixed linear models were applied to evaluate changes in immunological, metabolic and other safety parameters.</p><p>Results and discussion</p><p>In this analysis, 100 patients starting RPV plus ABC/3TC were included. By 12, 24 and 36 months after switching to RPV plus ABC/3TC, the proportions of individuals without TF were 88% [95% confidence interval (CI): 79%-93%], 82% (95% CI:73%-89%) and 78% (95% CI:68%-86%), respectively. Time to TF was not significantly influenced by CD4+ nadir (≤200 vs >200 cells/μl; log-rank test: p = 0.311) or pre-ART viral load (<100000 vs ≥100000 copies/mL; log-rank test: p = 0.574) or the type of previous antiretroviral regimen (PI+2NRTIs vs NNRTI+2NRTIs vs Other; log-rank test: p = 0.942).</p><p>Over a median follow-up of 2.9 years (IQR: 1.9–3.5), 26 subjects discontinued the treatment [10 due to toxicity, 7 for interactions with other drugs, 3 due to cardiovascular risk concern, 2 due to single viral blip, 1 due to VF, 1 for asthma, 1 patient’s decision, 1 due to enrolment in a study protocol].</p><p>Conclusions</p><p>In this retrospective study, long-term use of RPV plus ABC/3TC regimen is effective and safe. Efficacy of this regimen was not found to be affected by low CD4+ nadir or high pre-ART viral load.</p></div

Patients’ characteristics at the start of the RPV plus ABC/3TC regimen.

<p>Patients’ characteristics at the start of the RPV plus ABC/3TC regimen.</p

Univariate mixed linear models: Annual changes in immunological, metabolic and other safety parameters while on treatment with a RPV plus ABC/3TC regimen.

<p>Univariate mixed linear models: Annual changes in immunological, metabolic and other safety parameters while on treatment with a RPV plus ABC/3TC regimen.</p

Reasons for discontinuation among subjects with undetectable viral load.

<p>Reasons for discontinuation among subjects with undetectable viral load.</p

Treatment failure probability.

<p>Treatment failure probability.</p