{"id":11698,"date":"2003-09-01T10:11:57","date_gmt":"2003-09-01T10:11:57","guid":{"rendered":"http:\/\/i-base.info\/htb\/?p=11698"},"modified":"2014-05-27T11:26:29","modified_gmt":"2014-05-27T11:26:29","slug":"xii-international-hiv-drug-resistance-workshop","status":"publish","type":"post","link":"https:\/\/i-base.info\/htb\/11698","title":{"rendered":"XII International HIV Drug Resistance Workshop, Los Cabos, Mexico, 10-14 June 2003"},"content":{"rendered":"<p><strong>Reports by Simon Collins, Polly Clayden, Graham McKerrow and Steve Taylor for HIV i-Base<\/strong><\/p>\n<p><strong>Probably the most useful insights into the importance of future clinical developments come from the annual Resistance Workshop, restricted to around 150 researchers and this year only one HIV-positive community place. So while we\u2019d like to bring you an in-depth report from the meeting, we will have instead to report from the abstracts. These are now available online at:<\/strong><br \/>\n<strong> <a href=\"http:\/\/www.mediscover.net\/journals.cfm\"> http:\/\/www.mediscover.net\/journals.cfm<\/a><\/strong><\/p>\n<p>The abstract book repays reading, and although some of these studies were subsequently presented at the IAS meeting in Paris, among the technical presentations often focusing on the minutiae of resistance were many studies that included findings that impact directly on clinical care.<\/p>\n<p>These included:<\/p>\n<ul>\n<li>Increases in transmission of drug resistant virus \u2013 which was detected in 11% of cases of primary infection in Europe (abstract 117) and in 17% of drug na\u00efve individuals in the UK (abstract 124);<\/li>\n<li>Further discussion about coinfection and superinfection &#8211; data revealed that with coinfection, both viruses were likely to remain present over time, whereas in superinfection the new and fitter virus often outgrows the first (abstracts 62, 63);<\/li>\n<li>Much higher rates or nevirapine resistance than previously reported from single-dose nevirapine used to prevent mother-to-child transmission, were found by looking at earlier samples and minority viral populations &#8211; at least 75% of women showed evidence of resistance to nevirapine two weeks after a single-dose during pregnancy (abstracts 78, 79);<\/li>\n<li>Transmission of drug resistant virus does not readily revert to wild-type even in the absence of drug, and does not appear to carry substantial reduced replicative capacity (abstracts 80, 115);<\/li>\n<li>Currently available commercial resistance assays are insufficiently sensitive to detect low level resistance and minority populations (abstract 86, and 134, 143);<\/li>\n<li>Cross resistance between nevirapine and efavirenz can occur even in the absence of detection of key genotypic mutations detectable by population sequencing (abstracts 134, 143);<\/li>\n<li>Some drugs continue to contribute an antiviral effect, even in the presence of mutations (d4T \u2013 abstract 133, and 3TC \u2013 abstract 140);<\/li>\n<li>Replicative capacity results may be distorted by the presence of even low levels of wild-type virus in the assay (abstract 85);<\/li>\n<li>The choice of concomitant nucleosides and particularly thymidine analogue in tenofovir-including regimens may protect against MDR K65R mutation (abstracts 135, 136, 137) and possible CD8 mediated responses to tenofovir resistance from a macaques study (abstract 70). Other TDF related abstracts include 29, 30, 33, and 34;<\/li>\n<li>Indication that diversity in responses to controlling viraemia following treatment interruption (in the SSITT trial) can be explained by differences in virus, rather than host immune response (abstract 56);<\/li>\n<li>Analysis of residual viral replication below 50 copies \u2013 and the suggestion that resistance doesn\u2019t generally occur &lt; 50 copies due to only localised immune responses and fails to generate HIV-specific memory cells which are required to generate new resistant variants within the memory pool (abstract 57);<\/li>\n<li>Frequent discordant resistance profiles between plasma and the genital tract, with nucleoside-associated mutations (to AZT and 3TC) maintained in the vaginal tract up to four years after discontinuing those treatments (abstract 68). A second study showed transmission of and maintenance of AZT resistant virus on the male genital tract (abstract 83);<\/li>\n<li>Immunological benefit of T-20 despite resistance and shift to NSI CCDR5 virus (abstract 72).<\/li>\n<\/ul>\n<p>Short reports follow for each of these subjects.<\/p>\n<ul>\n<li><a title=\"Permanent link to Transmission of drug resistance \u2013 at 11% in Europe and 17% in the UK\" href=\"https:\/\/i-base.info\/htb\/11694\" rel=\"bookmark\">Transmission of drug resistance \u2013 at 11% in Europe and 17% in the UK<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to HIV coinfection, reinfection and superinfection\" href=\"https:\/\/i-base.info\/htb\/11691\" rel=\"bookmark\">HIV coinfection, reinfection and superinfection<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Single-dose nevirapine resistance in over 75% of mothers\" href=\"https:\/\/i-base.info\/htb\/11689\" rel=\"bookmark\">Single-dose nevirapine resistance in over 75% of mothers<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Transmission of drug resistant virus does not revert to wild-type and does not appear \u2018less fit\u2019\" href=\"https:\/\/i-base.info\/htb\/11686\" rel=\"bookmark\">Transmission of drug resistant virus does not revert to wild-type and does not appear \u2018less fit\u2019<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Standard genotype assays may miss 75% of mutations when present in less than 35% of plasma sample\" href=\"https:\/\/i-base.info\/htb\/11683\" rel=\"bookmark\">Standard genotype assays may miss 75% of mutations when present in less than 35% of plasma sample<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Low-level resistance and minority populations: cross resistance between nevirapine and efavirenz occurs even in the absence of genotypic mutations found using population sequencing\" href=\"https:\/\/i-base.info\/htb\/11681\" rel=\"bookmark\">Low-level resistance and minority populations: cross resistance between nevirapine and efavirenz occurs even in the absence of genotypic mutations found using population sequencing<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Persistent effect of d4T and 3TC, but not NNRTIs in the presence of associated genotypic mutations\" href=\"https:\/\/i-base.info\/htb\/11679\" rel=\"bookmark\">Persistent effect of d4T and 3TC, but not NNRTIs in the presence of associated genotypic mutations<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Replicative capacity results complicated by minority wild-type virus\" href=\"https:\/\/i-base.info\/htb\/11677\" rel=\"bookmark\">Replicative capacity results complicated by minority wild-type virus<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Tenofovir, resistance and K65R and concomitant nucleosides\" href=\"https:\/\/i-base.info\/htb\/11674\" rel=\"bookmark\">Tenofovir, resistance and K65R and concomitant nucleosides<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Response to STI is determined by virus rather than immunological response\" href=\"https:\/\/i-base.info\/htb\/11672\" rel=\"bookmark\">Response to STI is determined by virus rather than immunological response<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Why resistance rarely develops with viral suppression &lt;50 copies\/mL\" href=\"https:\/\/i-base.info\/htb\/11669\" rel=\"bookmark\">Why resistance rarely develops with viral suppression &lt;50 copies\/mL<\/a><\/li>\n<\/ul>\n<ul>\n<li><a title=\"Permanent link to Long-term persistence of distinct mutations in genital tract\" href=\"https:\/\/i-base.info\/htb\/11667\" rel=\"bookmark\">Long-term persistence of distinct mutations in genital tract<\/a><\/li>\n<\/ul>\n<p>Unless stated otherwise, all abstracts in the references refer to the XII International HIV Drug Resistance Workshop, Los Cabos, Mexico, 10-14 June 2003 and are published as part of Antiviral Therapy Volume 8 Issue 3.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Reports by Simon Collins, Polly Clayden, Graham McKerrow and Steve Taylor for HIV i-Base Probably the most useful insights into the importance of future clinical developments come from the annual Resistance Workshop, restricted to around 150 researchers and this year &hellip;<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,36],"tags":[12,109],"class_list":["post-11698","post","type-post","status-publish","format-standard","hentry","category-conference-reports","category-drug-resistance","tag-conference-index","tag-idrw-12th-2003"],"_links":{"self":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/11698","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\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/comments?post=11698"}],"version-history":[{"count":0,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/11698\/revisions"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/media?parent=11698"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/categories?post=11698"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/tags?post=11698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}