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Non-B Subtype ART — SCE Infectious Diseases MCQ

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ModerateHIV MedicineNon-B Subtype ARTSCE Infectious Diseases

A 28-year-old man with a new HIV diagnosis has genotypic resistance testing performed. The result shows no clinically significant resistance mutations. However, his subtype is CRF02_AG. How does non-B subtype affect ART management?

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Correct answer: E — Non-B subtypes (including CRF02_AG) may have naturally occurring polymorphisms at sites relevant to drug resistance — standard INSTI-based first-line ART remains effective, but subtype should be documented for future resistance interpretation

HIV-1 subtypes/CRFs have natural polymorphisms that can affect baseline resistance mutation interpretation. For example, some non-B subtypes have naturally occurring amino acid variations at positions relevant to NNRTI or PI resistance. However, current first-line INSTI-based regimens (DTG, BIC) have equivalent efficacy across all subtypes. The key exception relevant to current practice: subtype A1 with BMI >30 is a risk factor for Cabotegravir/Rilpivirine long-acting injectable failure (BHIVA 2025). Subtype should be documented for reference when interpreting future resistance tests.

Reference: BHIVA 2025 – ART guidelines; Stanford HIV Drug Resistance Database 2024