Evaluation of the treatment-experienced patient failing HIV therapy

VL: viral load; ART: antiretroviral therapy; INSTI: integrase strand transfer inhibitor; NRTI: nucleoside reverse transcriptase inhibitor; NNRTI: non-nucleoside reverse transcriptase inhibitor; PI: protease inhibitor.
* The use of resistance testing as part of the initial evaluation in patients who present off treatment is unclear. Testing to assess for drug resistance is best done while the patient is on their failing regimen or within the first 4 weeks of discontinuing treatment, since low levels of resistant virus cannot be excluded in the absence of drug pressure.
¶ For some patients, adherence can be improved with the use of interventions such as pill packs, alarms, and/or enhanced family support. However, other patients have behavioral barriers to adherence (eg, depression, substance use) that may require longer, more intensive interventions.
Δ In patients previously on an ART regimen with a low barrier to resistance, it is reasonable to change to a regimen with a higher barrier to resistance. However, some patients may wish to restart their prior regimen if it was well tolerated.
◊ Resistance testing should be performed in patients with a poor virologic response while the patient is on therapy. A poor virologic response is considered <1 log decrease in VL in the first month or VL >200 copies/mL by 12 to 24 weeks.
§ Resistance testing typically includes a standard genotype. For those failing an INSTI-containing regimen, a test for INSTI resistance should be performed as well.
¥ One of these agents should have a high barrier to resistance.
‡ If insufficient information is available to assess patient's prior treatment history, we usually initiate a regimen that includes a pharmacologically boosted PI, since in the short term, this type of regimen is unlikely to select for resistance mutations beyond those that had been previously selected for.
† For information on regimen selection in patients with a VL below the level of assay detection, refer to the UpToDate topic that discusses switching antiretroviral regimens in patients with a suppressed viral load.