Page 31 - HIV/AIDS Guidelines

Table 4. Recommendations for Using Drug-Resistance Assays
Page 2 of 2

Clinical Setting/Recommendation Rationale
Drug-resistance assay recommended

Addition of phenotypic assay to genotypic assay is generally Phenotypic testing can provide useful additional information for
preferred for those with known or suspected complex drug- those with complex drug-resistance mutation patterns,
resistance patterns, particularly to PIs (BIII). particularly to PIs.

In patients with suboptimal suppression of viral load: Drug- Testing can help determine the role of resistance and thus assist
resistance testing is recommended for persons with suboptimal the clinician in identifying the number of active drugs available
suppression of viral load after initiation of ART (AII). for a new regimen.
In HIV-infected pregnant women: Genotypic resistance testing is The goal of ART in HIV-infected pregnant women is to achieve
recommended for all pregnant women prior to initiation of ART maximal viral suppression for treatment of maternal HIV
(AIII) and for those entering pregnancy with detectable HIV RNA infection and for prevention of perinatal transmission of HIV.
levels while on therapy (AI). Genotypic resistance testing will assist the clinician in selecting
the optimal regimen for the patient.
Drug-resistance assay not usually recommended

After therapy discontinued: Drug-resistance testing is not Drug-resistance mutations might become minor species in the
usually recommended after discontinuation (>4 weeks) of ARV absence of selective drug pressure, and available assays might
drugs (BIII). not detect minor drug-resistant species. If testing is performed
in this setting, the detection of drug resistance may be of value;
however, the absence of resistance does not rule out the
presence of minor drug-resistant species.

In patients with low HIV RNA levels: Drug-resistance testing is Resistance assays cannot be consistently performed given low
not usually recommended in persons with a plasma viral load HIV RNA levels.
<500 copies/mL (AIII).

References

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recommendations of an International AIDS Society-USA panel. Clin Infect Dis. 2008;47(2):266-285.
2. Flandre P, Costagliola D. On the comparison of artificial network and interpretation systems based on genotype
resistance mutations in HIV-1-infected patients. AIDS. 2006;20(16):2118-2120.
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Antiviral Res. 2006;71(2-3):335-342.
4. Gianotti N, Mondino V, Rossi MC, et al. Comparison of a rule-based algorithm with a phenotype-based algorithm for the
interpretation of HIV genotypes in guiding salvage regimens in HIV-infected patients by a randomized clinical trial: the
mutations and salvage study. Clin Infect Dis. 2006;42(10):1470-1480.

5. Torti C, Quiros-Roldan E, Regazzi M, et al. A randomized controlled trial to evaluate antiretroviral salvage therapy
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7. Lanier ER, Ait-Khaled M, Scott J, et al. Antiviral efficacy of abacavir in antiretroviral therapy-experienced adults harbouring
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Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents C-13

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