DTG/3TC, Fostemsavir Effective as ART for Patients With HIV

Both dolutegravir/lamivudine (DTG/3TC; Dovato; ViiV Healthcare) and fostemsavir (Rukobia; ViiV Healthcare) demonstrated efficacy in maintaining viral suppression in patients with HIV in study results presented at the Conference on Retroviruses and Opportunistic Infections 2025, held in San Francisco, California, from March 9 to March 12, 2025. The studies could offer alternative treatments for those who are resistant to other drugs.

Efficacy of Maintaining Viral Suppression Using DTG/3TC

The PASO-DOBLE study presented at the conference1 focused on the efficacy of DTG/3TC in maintaining viral suppression when patients switched to taking it when compared with bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) (Biktarvy; Gilead Sciences). The study also aimed to assess the weight gain of the patients who used the DTG/3TC compared with BIC/FTC/TAF.

Participants of that study were those who were virologically suppressed, were clinically stable, and were on regimens that involved 1 or more pills per day, boosters, or drugs with cumulative toxicity. These patients were randomized and received either DTG/3TC or BIC/FTC/TAF. The groups were stratified by TAF and sex at birth at baseline. Unadjusted differences between the groups were calculated and focused on HIV RNA of less than 50 copies/mL and weight gain of more than 5% after 48 weeks.

Both dolutegravir/lamivudine and fostemsavir proved effective as antiretroviral therapy in people living with HIV. | Image credit: Sakdatorn - stock.adobe.com

The study took place between July 14, 2021, and March 24, 2023. A total of 277 participants switched to DTG/3TC, and 276 switched to BIC/FTC/TAF. A total of 27% of the total participants were women, and 28% were using TAF at baseline.

Differences in viral suppression were found between DTG and BIC/FTC/TAF in favor of DTG/3TC in individuals with tenofovir disoproxil at baseline (8.2%; 95% CI, 0.1-16.2), individuals aged 35 to 50 years (9.6%; 95% CI, 0.3-18.9), and individuals of Latin-American ethnicity (11.8%; 95% CI, 1.0-22.7). Women (–22.5%; 95% CI, –37.9 to –7.1), individuals aged 35 to 50 years (–15.5%; 95% CI, –29.0 to –2.1), individuals with no prior AIDS (–9.5%; 95% CI, –17.9% to –1.1%), individuals of Latin-American ethnicity (–16.9%; 95% CI, –33.3 to –0.4), and individuals with CD4 cells of 500/mm3 before the switch (–10.4%; 95% CI, –18.9 to –1.8) had significantly lower proportions of people living with HIV who had a weight gain of more than 5%.

"The relevance of these results lies in the importance in identifying groups of people who may be more susceptible to significant weight gain under these regimens," Juan Tiraboschi, MD, PhD, co-author of the study and a research doctor at Bellvitge University Hospital, said in a statement to The American Journal of Managed Care®. "Additionally, it is important to highlight that, besides the 'yet to confirm' impact that TAF may potentially have on weight gain, the previous treatment (if including TDF [tenofovir disoproxil fumarate] or NNRTIs [non-nucleoside reverse transcriptase inhibitors]) may play a significant role."

The researchers concluded that DTG/3TC had a non-inferior efficacy when compared with BIC/FTC/TAF, and DTG/3TC was favored when it came to weight gain. However, these results should be taken with some caution due to the analysis not being adjusted.

Efficacy of Maintaining Viral Suppression With Fostemsavir

Similarly, researchers also tested the efficacy of fostemsavir in people living with HIV in combination with other antiretrovirals in those who had multidrug resistance.2 Participants who started fostemsavir between July 2, 2020, and August 1, 2023, were chosen from the Trio Health HIV Cohort and had a 12-month follow-up period of observation. Viral suppression of less than 50 copies/mL, virologic failure, CD4 recovery, and a change of CD4 count at 6 and 12 months acted as the primary outcomes in the study. Class resistance of antivirals was defined as intermediate or high resistance to at least 1 antiviral. All analyses were stratified by viral load.

There were 77 people living with HIV who were included in the study, of which 31 were suppressed and 46 were not. A new optimized background therapy was prescribed alongside fostemsavir in 54% of those who were not suppressed at baseline, whereas 70% of those who were virologically suppressed added fostemsavir to their existing regimen.

A total of 74% of those not suppressed and 71% suppressed continued to use fostemsavir after 12 months; 24% of those not suppressed and 6% of those suppressed were lost to follow-up. A total of 36% of those not suppressed had an undetectable viral load within 12 months, and 77% of those suppressed maintained suppression; 12% of the suppressed group had virologic failure. CD4 recovery was found in 36% of those not suppressed and 38% of those suppressed, and increases in CD4 were found in both groups.

The researchers concluded that suppression was maintained in most of the people living with HIV who had been previously suppressed, and those who were suppressed had higher gains in CD4 when compared with those not suppressed.

Both studies demonstrate alternate methods of treatment for those living with HIV who are virally suppressed. These results demonstrate that virally suppressed patients with drug resistances continue to have options to maintain their viral suppression that are just as effective as existing options.

References

1. Tiraboschi JM, Crusells MJ, Domingo P, et al. Switch to DTG/3TC vs BIC/FTC/TAF (PASO-DOBLE study): efficacy and weight changes by predefined subgroups. Presented at Conference on Retroviruses and Opportunistic Infections 2025; March 9-12, 2025; San Francisco, CA. Abstract 661
2. Ramgopal M, Henegar C, Frick AJ, et al. Characteristics and treatment outcomes of people with HIV prescribed fostemsavir in the TRIO cohort. Presented at Conference on Retroviruses and Opportunistic Infections 2025; March 9-12, 2025; San Francisco, CA. Abstract 699