Thanks to Dan Kuritzkes+Suzanne McCluskey for talk on drug resistance today in the HIV core lecture series! @MGHBWHIDFellows #IDFellows @ID_Fellows #IDTwitter
To review high yield mutations, check these prior 🧵
NRTI:
NNRTI:
Additional NNRTI mutations:
🧬E138K🧬
▪️Key rilpivirine resistance mutation
▪️Cross-resistance to ETR
🧬V106I, F227C🧬
▪️Key doravirine resistance mutations
Notes on PI resistance:
🔹RTV-boosted PIs have high barrier to resistance
🔹Prolonged use in setting of virologic failure can select for resistance
🔹More mutations = broader cross-resistance
🔹Certain mutations confer resistance to some drugs, sensitize to others: I50L, L76V
Notes on INSTI resistance:
🔹Resistance common at time of virologic failure for RAL, EVG
🔹To date, de novo emergence of resistance to DOL and BIC is rare
🔹Extensive cross-R bt RAL, EVG
🔹Many RAL and EVG-R isolates remain susceptible to DOL and BIC
When to consider resistance testing:
🔷ART naive: initiating ART
🔷ART experienced:
🔹Re-initiating ART
🔹Virologic failure (most successful if HIV RNA >1000 cp/mL but can consider if 500-1000 cp/mL)
🔹Sometimes: low level viremia, suppressed and contemplating regimen switch
Resistance test timing for ART-experienced
🔸Most ideal: on therapy
🔸Next best: within 4 wks of being off ART
🔸Least useful: off ART >4wks
Assemble the cumulative genotype as some mutations may not be detected:
🔸 if mutant <20% viral popul
🔸if archived in reservoir
🔸some mutations persist w/o drug pressure, but many do not