An all-oral regimen of Biktarvy plus Pifeltro maintained viral suppression in people with highly drug-resistant HIV who switched from an older combination regimen, according to a small study published in the journal AIDS.

Modern antiretroviral therapy is highly effective, but people whose virus has developed resistance to multiple medications may have more trouble constructing a regimen that is both potent and convenient to use. Some regimens that work for such individuals require multiple pills or injections. What’s more, long-term survivors may be taking other medications for coexisting conditions that can limit treatment options.

Felicia Sterman, MD, of Gilead Sciences, and colleagues evaluated the safety and efficacy of switching treatment for highly treatment-experienced people with HIV. The study included 20 men, almost all white, who had a median age of 65 years and had been living with HIV for a median of 37 years.


All participants in this open-label study switched from the Odefsey combination pill (rilpivirine/tenofovir alafenamide/emtricitabine) plus Tivicay (dolutegravir) to the Biktarvy coformulation (bictegravir/tenofovir alafenamide/emtricitabine) plus Pifeltro (doravirine). Both regimens are roughly similar in composition. The first includes the nonnucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine in the coformulation with the integrase inhibitor dolutegravir taken as a separate pill. The second contains the integrase inhibitor bictegravir in the combination pill with the NNRTI doravirine taken separately. Odefsey, Biktarvy and Pifeltro are taken as one tablet once daily; Tivicay is also usually taken once daily, but people with preexisting integrase inhibitor resistance take it twice daily.

The participants had documented resistance to protease inhibitors, nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and/or NNRTIs but no known resistance to rilpivirine or doravirine and no K65R or T69 mutations, which confer resistance to tenofovir and other NRTIs. At study entry, all had an undetectable viral load (50 or less) on Odefsey plus Tivicay for at least six months.


At 48 weeks after the switch, 100% of participants still had a viral load below 50. The Biktarvy plus Pifeltro regimen was safe and well tolerated with no treatment-related adverse events, and there were no apparent interactions between bictegravir and doravirine. Body mass index did not change, which is a potential concern with integrase inhibitors, especially when taken with tenofovir alafenamide. Sleep quality and overall quality of life also did not change.


These findings show that switching from Odefsey plus Tivicay to Biktarvy plus Pifeltro is an effective and well-tolerated option for highly treatment-experienced older men with HIV, the study authors concluded, especially considering that the latter regimen is compatible with medications commonly used to manage comorbidities.


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