Resistance profile
Another advantage of dolutegravir relates to the barrier to
resistance. When analyzing those experiencing virologic
failure while on dolutegravir as first-line therapy, no resistance
mutations were discovered.68 This contrasts with the
four of 281 patients who developed raltegravir resistance in
STARTMRK at 5 years and one of 411 patients in SPRING-2
at 96 weeks.13,45 In comparison, at week 144, elvitegravirresistant
virus was observed in nine of 348 patients and
six of 353 patients in studies comparing it to efavirenz and
atazanavir–ritonavir, respectively.69,70 It is unclear as to
whether the resistance barrier to dolutegravir is similar to or
surpasses that of PIs, as virologic failure due to resistance
was not observed in FLAMINGO.47