How do you pick which drug to prescribe for your patients with HIV? New results presented at CROI 2025 from the PASO-DOBLE study have found that patients taking the integrase strand transfer inhibitor (INSTI) combination drug dolutegravir-lamivudine (Dovato, ViiV Healthcare) had less weight gain than others taking bictegravir-emtricitabine–tenofovir alafenamide fumarate (Biktarvy, Gilead). However, investigator Juan Tiraboschi, MD, told Pharmacy Practice News that these are only preliminary results after one year of the two-year study, and he notes that the results are from an unadjusted analysis (abstract 661). 

For more research from CROI 2025, head to our meetings news page.

00:14
Hello, my name is Juan Tiraboschi and I'm a consultant physician in ID and HIV, at Bellvitge University Hospital, in Barcelona. And I'm one of the investigators of the PASO-DOBLE study. So, as you may know, the PASO-DOBLE study is a big study. It's probably one of the biggest ones in terms of switching in Spain, ever. So this is a study being conducted in 30 sites across Spain, and it's a collaborative study between [the] SEIMC-GeSIDA [Foundation] and ViiV Healthcare.

00:55
So in this study, the patients were simplifying their treatments to either Dovato or Biktarvy. And we were looking at the impact on viral suppression and metabolic changes, specifically at body weight increase. So the study was powered to detect if significant differences [occur] in terms of body weight changes. And in this study we presented yesterday at CROI 2025, we were assessing some specific subgroups. This is a substudy. What we [were] assessing [was] these subgroups specifically: those with demographic, clinical and treatment baseline characteristics.

1:44 
We recruited in the study around 500 participants who were randomized to either Dovato or Biktarvy. And after one year of follow-up, what we found is that in terms of virological suppression, the results were roughly the same: very high levels of viral suppression in both arms. But in terms of weight changes specifically, those changes that are clinically significant-which is more than 5% from baseline-we found that some specific subgroups, like women, for example, aged between 35 and 50 years [and] Latino background, and those who were switching out from strategies containing TDF [tenofovir disoproxil fumarate] or other NRTIs [nucleotide reverse transcriptase inhibitors] were the most affected significantly. And they increased their body weight significantly more when they were receiving bictegravir-emtricitabine-tenofovir alafenamide fumarate.


2:55
So one of the most significant things of this study, I think, is that we detected probably some more vulnerable people ... susceptible people to modify their body weight, but depending on the treatments that we are offering them. So, and the thing is, it's important to highlight that the most important thing is really the treatment they were switching off. So, in this case, again, from the TDF or an NRTI-based regimen, they were the ones more affected by this, a clinically significant change or increase in weight.

3:50
I think it's important because we need to think that these people are going to be taking treatments for a long time, a long lifetime probably ... life expectancy is so long now. They're going to be under these potential modifiers for a long period of time.

4:24
We need to say also that these results we presented yesterday are coming from a nonadjusted analysis. So they need to be taken into proportion. And with regard to the resource, I think we need to also think this is a two-year ... follow-up study. These are just the preliminary results, the results of the first year. And we see whether these results are confirmed with the second-year, follow-up results.