{"id":24887,"date":"2014-03-24T11:56:57","date_gmt":"2014-03-24T11:56:57","guid":{"rendered":"http:\/\/i-base.info\/htb\/?p=24887"},"modified":"2014-03-28T16:25:39","modified_gmt":"2014-03-28T16:25:39","slug":"nnrti-resistance-found-in-12-of-people-stopping-treatment-with-undetectable-viral-load-implications-for-stock-outs-2","status":"publish","type":"post","link":"https:\/\/i-base.info\/htb\/24887","title":{"rendered":"NNRTI resistance found in 12% of people stopping treatment with undetectable viral load: implications for stock-outs"},"content":{"rendered":"

Simon Collins, HIV i-Base <\/strong><\/p>\n

\"CROIAlthough stopping ART is not recommended, this still occurs due to drug stock-outs in some countries and retrospective data from the UK HIV Drug Resistance Database (HDRD) highlighted the risk this has for developing drug resistance. <\/strong><\/p>\n

Valentina Cambiano from University College London and colleagues analysed drug resistance mutations in rebound viraemia in people who interrupted NNRTI-based treatment when their viral load was consistently undetectable <200 copies\/mL for at least six months and who had no prior evidence of NNRTI resistance.<\/p>\n

Of 208 eligible patients with a resistance test after stopping treatment, 39% were on efavirenz and 61% on nevirapine. Background therapy was most commonly with 3TC (85%) and\/or AZT (63%) and treatment was stopped after a median of 12 months on ART (IQR: 5-32 months).<\/p>\n

At the first resistance test after stopping treatment, 25\/208 patients (12%, 95% CI: 8-17) had one or more major NNRTI mutations, with no indication of a reduced rate in the 20\/208 people who staggered the interruption, though small numbers meant that there were wide confidence intervals around these estimates. In these patients, the resistance test was taken after a median of 12 months (IQR: 3-20).<\/p>\n

The most common mutations were K103N (64%) and G190A (12%), with K101E, V108I, \u00a0Y181C, \u00a0L100I, V106A, Y188L and P225H found in 8% (n=2) or less. In multivariate analysis, the only independent predictor of NNRTI resistant mutations was a lower CD4 count nadir (RR per 100 cells higher = 0.67; 95% CI: 0.53-0.85; p=0.001).<\/p>\n

The authors concluded that in this largest study to date, NNRTI resistance was common occurring in 12% of patients tested. Although this was a retrospective analysis, this may underestimate the risk given the time taken between stopping treatment and testing for drug resistance.<\/p>\n

comment<\/h3>\n

These results are important in countries where the drug supply is less secure, and when using NNRTI-based ART with AZT and\/or 3TC. Further research is needed to determine whether the longer half-life of tenofovir has a protective impact on NNRTI resistance in this context. <\/strong><\/p>\n

This also highlights the lack of research into the clinical outcomes of people who do not have access to an assured and continuous supply of ARVs. While stock-outs are commonly reported, research into the outcomes is not. <\/strong><\/p>\n

A recent paper in HIV Medicine reported resistance data after stopping atazanavir\/r-based combinations (largely related to poor adherence), and suggested a benefit of PI\/r-based combinations when stock-outs are common. This was a retrospective analysis of 110 patients in Ireland and although minor PI mutations were common, viral load was resuppressed after restarting atazanavir\/r. [2] <\/strong><\/p>\n

Reference<\/p>\n

1. Cambiano V et al. Detection of NNRTI resistance mutations after interrupting NNRTI-based regimens. 21st CROI, 3\u20136 March 2014, Boston. Poster abstract 593.
\nhttp:\/\/croiconference.org\/sites\/all\/abstracts\/593.pdf <\/a>\u00a0(PDF)<\/p>\n

2. Tinago W et al. Characterisation of associations and development of atazanavir resistance after unplanned treatment interruptions. HIV Medecine (2014), 15 (4) 224-232. \u00a0DOI: 10.1111\/hiv.12107.
\nhttp:\/\/www.ncbi.nlm.nih.gov\/pubmed\/24215370<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Simon Collins, HIV i-Base Although stopping ART is not recommended, this still occurs due to drug stock-outs in some countries and retrospective data from the UK HIV Drug Resistance Database (HDRD) highlighted the risk this has for developing drug resistance. …<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,41,36],"tags":[187],"class_list":["post-24887","post","type-post","status-publish","format-standard","hentry","category-conference-reports","category-treatment-strategies","category-drug-resistance","tag-croi-2014"],"_links":{"self":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/24887","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/comments?post=24887"}],"version-history":[{"count":0,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/24887\/revisions"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/media?parent=24887"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/categories?post=24887"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/tags?post=24887"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}