HIV-1 integrase inhibitor resistance among treatment naïve patients in the West of Scotland.

Background: Transmitted integrase inhibitor resistance is rare, with only a small number of cases reported world-wide to date.

Objectives: The aim of this study was to assess whether transmitted integrase inhibitor resistance has occurred in Scotland and if so, could there be a case for performing genotypic integrase resistance testing at baseline.

Study Design: The study population consisted of 106 treatment naïve, newly diagnosed, HIV positive patients. The patient samples were collected between October 2015 and March 2016 at the time of HIV diagnosis and prior to initiation of anti-retroviral therapy. The integrase region was amplified and sequenced.

Results: We detected integrase inhibitor resistance (T66I/T) at baseline in one patient sample. This is a non-polymorphic mutation seen in patients receiving elvitegravir which confers high-level resistance to elvitegravir and intermediate resistance to raltegravir. A further 10 patients had accessory mutations which have minimal or no effect on susceptibility to integrase inhibitors.

Conclusions: Transmitted integrase inhibitor resistance remains rare. The results of the present study do not support performing integrase resistance testing at baseline.