Viral resuppression and detection of drug resistance following interruption of a suppressive non-nucleoside reverse transcriptase inhibitor-based regimen

Copenhagen HIV Programme, University of Copenhagen/Rigshospitalet, Copenhagen, Denmark.
AIDS (London, England) (Impact Factor: 5.55). 12/2008; 22(17):2279-89. DOI: 10.1097/QAD.0b013e328311d16f
Source: PubMed


Interruption of a non-nucleoside reverse transcriptase inhibitor (NNRTI)-regimen is often necessary, but must be performed with caution because NNRTIs have a low genetic barrier to resistance. Limited data exist to guide clinical practice on the best interruption strategy to use.
Patients in the drug-conservation arm of the Strategies for Management of Antiretroviral Therapy (SMART) trial who interrupted a fully suppressive NNRTI-regimen were evaluated. From 2003, SMART recommended interruption of an NNRTI by a staggered interruption, in which the NNRTI was stopped before the NRTIs, or by replacing the NNRTI with another drug before interruption. Simultaneous interruption of all antiretrovirals was discouraged. Resuppression rates 4-8 months after reinitiating NNRTI-therapy were assessed, as was the detection of drug-resistance mutations within 2 months of the treatment interruption in a subset (N = 141).
Overall, 601/688 (87.4%) patients who restarted an NNRTI achieved viral resuppression. The adjusted odds ratio (95% confidence interval) for achieving resuppression was 1.94 (1.02-3.69) for patients with a staggered interruption and 3.64 (1.37-9.64) for those with a switched interruption compared with patients with a simultaneous interruption. At least one NNRTI-mutation was detected in the virus of 16.4% patients with simultaneous interruption, 12.5% patients with staggered interruption and 4.2% patients with switched interruption. Fewer patients with detectable mutations (i.e. 69.2%) achieved HIV-RNA of 400 copies/ml or less compared with those in whom no mutations were detected (i.e. 86.7%; P = 0.05).
In patients who interrupt a suppressive NNRTI-regimen, the choice of interruption strategy may influence resuppression rates when restarting a similar regimen. NNRTI drug-resistance mutations were observed in a relatively high proportion of patients. These data provide additional support for a staggered or switched interruption strategy for NNRTI drugs.

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Available from: Sean Emery, Aug 09, 2014
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    • "In this study, the patients in the Staggered Interruption group, who continued the use of 2 NRTIs for a median of 7 days after discontinuing NVP, had virological outcomes comparable to those of the Control group (Figure 1 and Table 2). These results are in accordance with a post-study analysis of the Strategies for Management of Antiretroviral Therapy (SMART) trial by Fox et al. [15]. Consequently, it should be appropriate to use a staggered interruption strategy if the NRTIs are to be continued for 7 days. "
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    ABSTRACT: Objective The objective of this work was to study the virological outcomes associated with two different types of treatment interruption strategies in patients with allergic reactions to nevirapine (NVP). We compared the virological outcomes of (1) HIV-1-infected patients who discontinued an initial NVP-based regimen because of cutaneous allergic reactions to NVP; different types of interruption strategies were used, and second-line regimen was based on efavirenz (EFV); and (2) HIV-1-infected patients who began an EFV-based regimen as a first-line therapy (controls). Methods This retrospective cohort included patients who began an EFV-based regimen, between January 2002 and December 2008, as either an initial regimen or as a subsequent regimen after resolving a cutaneous allergic reaction against an initial NVP-based regimen. The study ended in March 2010. The primary outcome was virological failure, which was defined as either (a) two consecutive plasma HIV-1 RNA levels >400 copies/mL or (b) a plasma HIV-1 RNA level >1,000 copies/mL plus any genotypic resistance mutation. Results A total of 559 patients were stratified into three groups: (a) Simultaneous Interruption, in which the subjects simultaneously discontinued all the drugs in an NVP-based regimen following an allergic reaction (n=161); (b) Staggered Interruption, in which the subjects discontinued NVP treatment while continuing nucleoside reverse transcriptase inhibitor (NRTI) backbone therapy for a median of 7 days (n=82); and (c) Control, in which the subjects were naïve to antiretroviral therapy (n=316). The overall median follow-up time was 43 months. Incidence of virological failure in Simultaneous Interruption was 12.9 cases per 1,000 person-years, which trended toward being higher than the incidences in Staggered Interruption (5.4) and Control (6.6). However, differences were not statistically significant. Conclusions Among the patients who had an acute allergic reaction to first-line NVP-based therapy and later began an EFV-based regimen, virological outcomes resulting from a staggered interruption of treatment (with a continuation of NRTI backbone therapy for 7 days after discontinuing NVP) did not differ from those of the patients who began an EFV-based regimen as their initial therapy (Control). However, the virological failure of Simultaneous Interruption was possibly higher than those of Control and Staggered Interruption.
    AIDS Research and Therapy 01/2013; 10(1):4. DOI:10.1186/1742-6405-10-4 · 1.46 Impact Factor
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    • "This scenario confirms the result of Fox et al. 2008, and highlights the need to interrupt NNRTI-based regimens wisely. Patients of the SMART study interrupting NNRTIbased regimens restarted later on the same regimen. "
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    ABSTRACT: Selection of the K103N mutation is associated with moderately reduced in vitro fitness of HIV. Strains bearing K103N in vivo tend to persist, even in the absence of additional drug pressure, as minority quasispecies, often undetectable in genotyping resistance testing assays, performed at standard conditions. Here, we report on the rapid and long lasting selection of a K103N bearing strain as the dominant quasispecies after very short exposure to efavirenz in vivo. A 55-year-old Caucasian man was switched to efavirenz, zidovudine and lamivudine in February 2003, while on viral suppression in his first-line highly active anti-retroviral treatment regimen. One month later, he reported inconsistent adherence and his viremia level was 5700 c/mL. He did not attend further checkups until September 2005, when his viral load was 181,000 c/mL. The patient reported interrupting his medications approximately three weeks after simplification. The genotyping resistance testing assay was performed both on HIV RNA and HIV DNA from plasma, yielding an identical pattern with the isolate presence of the K103N mutation in the prevalent strain. Persistence of the K103N mutation as a majority quasispecies may ensue after a very short exposure to efavirenz. Our case would therefore suggest that the presence of the K103N mutation should always be ruled out by genotyping resistance testing assays, even after minimal exposures to efavirenz.
    Journal of Medical Case Reports 09/2009; 3(1):9132. DOI:10.4076/1752-1947-3-9132
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