Another HIV duo-therapy option proves effective at 48 weeks
People living with HIV could soon have another duo-therapy option available to them after promising data presented at Virtual AIDS 2020.
MSD (Merck) showed off data from their DRIVE2simplify study which showed the combination of islatravir and doravirine (Pifeltro) maintained a supressed (undetectable) viral load for 48 weeks with only a small number of the participants experiencing virological rebound.
Islatravir is the first nucleoside reverse transcriptase translocation inhibitor (NRTTI) in the industry and works by scuppering the transcriptase process by masquerading as a cellular building block as well as preventing translocation of other chemicals important to the process.
This novel compound’s increased potency and long half-life (the amount of time it resides in the body) means it is also an ideal candidate for long-acting treatment of HIV or prevention of HIV as PrEP (Pre-Exposure Prophylaxis).
Doravirine (Pifeltro) is a classic non-nucleoside reverse transcriptase inhibitor (NNRTI) from MSD which has been on the market for some time now.
At the AIDS 2020 virtual conference Professor Chloe Orkin of Queen Mary University London presented the latest data from the DRIVE2Simplfy (phase IIb) study.
The randomised, double-blind, trial enrolled 121 people living with HIV with no known resistance to existing HIV antiretrovirals. The participant demographic was 90% male, 75% white, and an average age of 28.
Participants were randomised to one of four arms:
- 0.25mg islatravir + 100mg doravirine + 300mg lamivudine
- 0.75mg islatravir + 100mg doravirine + 300mg lamivudine
- 2.25mg islatravir + 100mg doravirine + 300mg lamivudine
- 100mg doravirine + 300mg lamivudine + 300mg tenofovir disoproxil fumerate (in the form of the single pill Delstrigo)
After 24 weeks those who had reached an undetectable viral load (<50 copies/ml) had the lamivudine removed from their combination and continued to week 48 with just the islatravir and doravirine.
The optimal dose was found to be 0.75mg islatravir with 90% of those on this dosage achieving an undetectable viral load by week 48 compared to 84% on traditional triple therapy.
Six out of the 121 participants experienced a protocol-defined virological failure (PDVF). Those who experienced a PDVF were returned to a standard regimen.
Viral rebound, although low (no one rebounded above 80 copies/ml), was experienced by:
- 2 people (7%) in the 0.25mg islatravir arm
- 2 people (7%) in the 0.75mg islatravir arm
- 1 person (3%) in the Delstrigo arm
- 1 one non-responder (3%) in the 2.25mg islatravir arm
Researchers concluded that the rebounds and low-level viremia compares to that of the general untreated population.