Integrase Inhibitor Resistance Testing Does Not Improve HIV Outcomes

Testing for integrase inhibitor resistance (IR) among individuals with newly diagnosed HIV starting antiretroviral therapy (ART) was projected to lead to worse outcomes compared with no testing, according to the projections of a recent study.

In their decision model analysis, the researchers assessed 96-week clinical outcomes and the cost-effectiveness of IR testing compared with no IR testing using a simulated cohort of patients with newly diagnosed HIV. The researchers estimated the base case prevalence of transmitted integrase strand transfer inhibitor (INSTI)–resistant (INSTI-R) virus to be 0.1%.
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All patients included in the no IR testing group started dolutegravir (DTG)–based ART after genotype testing. After 12 weeks, patients who had not achieved viral suppression received IR testing. Among those in the IR testing group, IR testing was used to diagnosis the presence of INSTI-R virus prior to initiating ART. Patients’ IR status was used to determine whether they initiated DTG- or ritonavir-boosted darunavir (DVR/r)-based regimens.

Overall, IR testing resulted in worse clinical outcomes and increased costs by $200 US per person per year compared with no IR testing. The preference for no baseline IR testing was not affected by the prevalence of transmitted INSTI-R virus. Additionally, no IR testing remained clinically preferred unless DTG suppression of INSTI-R virus was below 20% or 96-week DRV/r suppression was below 92%.

If DRV/r-based ART was associated with worse quality of life compared with DTG-based ART, no testing was clinically preferred over a wider range of parameters.

“In patients with newly diagnosed HIV, IR testing is projected to result in worse outcomes and is not cost-effective,” the researchers concluded. “Pretreatment assessment for INSTI resistance should not be recommended in treatment guidelines.”

—Melissa Weiss

Reference:

Koullias Y, Sax PE, Fields NF, Walensky RP, Hyle EP. Should we be testing for baseline integrase resistance in patients newly diagnosed with human immunodeficiency virus?. Clin Infect Dis. 2017;65;8: 1274–1281. https://doi.org/10.1093/cid/cix542.