Academy Exchange

I have a patient who has had very sporadic medical follow up over the last couple years as well as a history of taking her Biktarvy irregularly and possibly more importantly vomiting frequently after taking her Biktarvy. Kind of a perfect storm for inducing drug resistance. She now wants to try Cabenuva instead. She had an HIV RNA level of 1280 in December 2023 but was lost to follow up until September 2025 when it was 4220 (with a genotype showing no resistance to NRTIs, NNRTIs, PIs, or INSTIs). Her repeat HIV RNA was 1970 in December but this time her genotype revealed a T66A/T mutation predicting resistance to elvitegravir. I checked out the IAS-USA website and it noted that a T66K mutation predicts resistance to cabotegravir but not a T66A mutation. I also noted that T66 mutations of any type don't confer resistance to bictegravir--but she's not tolerating (and/or regularly taking) Biktarvy so continuing it seems a strategy likely to fail. Should I be concerned about using cabotegravir (in Cabenuva) because of the T66A mutation? Thanks, Steve

Steve

With respect to Cabenuva, I'd be more worried about her tendency to disappear than I would about the T66A mutation. Still, if she can't tolerate Biktarvy, she's probably not going to do well with any oral regimen. Cabenuva, combined with intensive adherence counseling and outreach services, may be her best bet. When it's used in poorly adherent patients, it's never an optimal situation, but it's not only worked for many such people, but has sometimes been lifesaving.

I have a patient who has had very sporadic medical follow up over the last couple years as well as a history of taking her Biktarvy irregularly and possibly more importantly vomiting frequently after taking her Biktarvy. Kind of a perfect storm for inducing drug resistance. She now wants to try Cabenuva instead. She had an HIV RNA level of 1280 in December 2023 but was lost to follow up until September 2025 when it was 4220 (with a genotype showing no resistance to NRTIs, NNRTIs, PIs, or INSTIs). Her repeat HIV RNA was 1970 in December but this time her genotype revealed a T66A/T mutation predicting resistance to elvitegravir. I checked out the IAS-USA website and it noted that a T66K mutation predicts resistance to cabotegravir but not a T66A mutation. I also noted that T66 mutations of any type don't confer resistance to bictegravir--but she's not tolerating (and/or regularly taking) Biktarvy so continuing it seems a strategy likely to fail. Should I be concerned about using cabotegravir (in Cabenuva) because of the T66A mutation? Thanks, Steve