Dataset Information

1024. Impact of Treatment Adherence on Efficacy of DTG/3TC and DTG + TDF/FTC: Pooled Analysis of the GEMINI 1 and 2 Clinical Trials

ABSTRACT: Abstract

Background

GEMINI 1 & 2 are global double-blind, multi-center phase III non-inferiority studies evaluating efficacy and safety of dolutegravir (DTG) + lamivudine (3TC) once daily in treatment-naive HIV-1-infected adults with Screening HIV-1 RNA ? 500,000 c/mL (ClinicalTrials.gov: NCT02831673/NCT02831764). Participants were randomized 1:1 to treatment with DTG+3TC or DTG + tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC). The primary endpoint was the proportion of participants with plasma HIV-1 RNA < 50 c/mL at Week 48 (Snapshot algorithm). DTG+3TC was non-inferior to DTG+TDF/FTC at Weeks 48 and 96. Here we evaluate the impact of treatment adherence on Week 48 virologic response (VR) within the GEMINI trials as a post-hoc analysis.

Methods

Adherence was estimated using pill counts data and categorized as follows: ? 90% vs < 90%. Week 48 VR was measured as % of participants with HIV-1 RNA < 50 c/mL by Food and Drug Administration Snapshot and by last on treatment viral load (VL) for the intention to treat–exposed population for which adherence could be derived. VR and differences between treatment arms within each adherence category were calculated along with exact unadjusted 95% confidence intervals.

Results

5% of participants had < 90% adherence in both treatment arms. Baseline VL and CD4+ cell counts were similar across adherence categories. VR was lower in the < 90% adherence group than the ? 90% group, but not different between the 2 treatment arms within the same adherence category: In the low adherence group, DTG+3TC VR was 69% compared to 65% in DTG+TDF/FTC arm by Snapshot and 91% and 85% respectively by last on treatment VL analysis (Table). Table.

Conclusion

In the GEMINI studies, a lower Week 48 VR was observed in participants with < 90% adherence, but the impact of lower adherence on VR was similar in the DTG+3TC compared with DTG+TDF/FTC arms. One limitation of the analysis is the small number of participants in the lower adherence subgroup. However, the results add further information about the robustness of DTG+3TC compared to 3-drug DTG-containing regimens and may suggest similar regimen forgiveness.

Disclosures

Mounir Ait-Khaled, PhD, ViiV Healthcare (Employee, Shareholder) Choy Man, BSc, ViiV Healthcare (Employee, Shareholder) Jorg Sievers, DPhil, ViiV Healthcare (Employee) Richard Grove, MSc, GSK/ViiV (Employee, Shareholder) Brian Wynne, MD, ViiV Healthcare (Employee) Rimgaile Urbaityte, MSc, GlaxoSmithKline (Employee, Shareholder) Jean A. van Wyk, MB,ChB, ViiV Healthcare (Employee, Shareholder) Debbie Hagins, MD, Gilead Sciences Inc. (Consultant, Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member)Janssen (Grant/Research Support)Merck (Consultant, Grant/Research Support, Advisor or Review Panel member)Viiv Healthcare (Consultant, Grant/Research Support, Advisor or Review Panel member) Andrew Zolopa, MD, ViiV Healthcare (Employee)

SUBMITTER: Ait-Khaled M

PROVIDER: S-EPMC7776490 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Project description:Abstract Background At Weeks 48 and 96 in the GEMINI-1 and GEMINI-2 studies (Clinicaltrials.gov: NCT02831673 and NCT02831764), the 2DR of DTG+3TC was noninferior to the three-drug regimen of DTG + tenofovir/emtricitabine (TDF/FTC) in achieving plasma HIV-1 RNA < 50 c/mL in treatment-naïve adults. Methods GEMINI-1 and 2 are identical, global, double-blind, multicenter Phase III studies. Participants with screening HIV-1 RNA ? 500.00 c/mL were randomized to once-daily DTG+3TC or DTG+TDF/FTC, stratified by plasma HIV-1 RNA and CD4+ cell count. The primary endpoint was the proportion of participants with plasma HIV-1 RNA < 50 c/mL at Week 48 (Snapshot algorithm). We present a secondary endpoint analysis of efficacy at Week 96 by baseline disease and demographic characteristics. For the overall population, estimates and confidence intervals were based on a stratified analysis using Cochran–Mantel–Haenszel weights. Results In total, 714 and 719 adults were randomized and treated in GEMINI-1 and -2, respectively. Based on a 10% noninferiority margin, DTG+3TC was noninferior to DTG+TDF/FTC at Week 96 in both GEMINI-1 and -2 and in the pooled analysis. Response rates across baseline HIV-1 RNA subgroups were high and similar in both arms in the pooled analysis, including in participants with baseline HIV-1 RNA >100,000 c/mL (Table 1). Results were also generally consistent regardless of age, gender, or race. In the CD4+ ? 200 cells/mm3 subgroup, response rates were lower in the DTG+3TC group compared with DTG+TDF/FTC; most reasons for nonresponse were unrelated to virologic efficacy or treatment regimen. Across both studies, 11 participants on DTG+3TC and 7 on DTG+TDF/FTC met protocol-defined virologic withdrawal criteria through Week 96; none had treatment emergent integrase-strand-transfer-inhibitor or NRTI resistance mutations. Conclusion In GEMINI-1 and 2, DTG+3TC was noninferior to DTG+TDF/FTC in treatment-naïve adults at Week 96, demonstrating durable efficacy. The results of subgroup analyses of efficacy at Week 96 were generally consistent with overall study results, and further demonstrate that DTG+3TC is an effective initial treatment for HIV-infected patients across a spectrum of disease characteristics and patient populations. The studies are ongoing. Disclosures All Authors: No reported Disclosures.

Project description:Success in treating hepatitis B virus (HBV) infection with nucleoside analog drugs like lamivudine is limited by the emergence of drug-resistant viral strains upon prolonged therapy. The predominant lamivudine resistance mutations in HBV-infected patients are Met552IIe and Met552Val (Met552Ile/Val), frequently in association with a second mutation, Leu528Met. The effects of Leu528Met, Met552Ile, and Met552Val mutations on the binding of HBV polymerase inhibitors and the natural substrate dCTP were evaluated using an in vitro HBV polymerase assay. Susceptibility to lamivudine triphosphate (3TCTP), emtricitabine triphosphate (FTCTP), adefovir diphosphate, penciclovir triphosphate, and lobucavir triphosphate was assessed by determination of inhibition constants (K(i)). Recognition of the natural substrate, dCTP, was assessed by determination of Km values. The results from the in vitro studies were as follows: (i) dCTP substrate binding was largely unaffected by the mutations, with Km changing moderately, only in a range of 0.6 to 2.6-fold; (ii) K(i)s for 3TCTP and FTCTP against Met552Ile/Val mutant HBV polymerases were increased 8- to 30-fold; and (iii) the Leu528Met mutation had a modest effect on direct binding of these beta-L-oxathiolane ring-containing nucleotide analogs. A three-dimensional homology model of the catalytic core of HBV polymerase was constructed via extrapolation from retroviral reverse transcriptase structures. Molecular modeling studies using the HBV polymerase homology model suggested that steric hindrance between the mutant amino acid side chain and lamivudine or emtricitabine could account for the resistance phenotype. Specifically, steric conflict between the Cgamma2-methyl group of Ile or Val at position 552 in HBV polymerase and the sulfur atom in the oxathiolane ring (common to both beta-L-nucleoside analogs lamivudine and emtricitabine) is proposed to account for the resistance observed upon Met552Ile/Val mutation. The effects of the Leu528Met mutation, which also occurs near the HBV polymerase active site, appeared to be less direct, potentially involving rearrangement of the deoxynucleoside triphosphate-binding pocket residues. These modeling results suggest that nucleotide analogs that are beta-D-enantiomers, that have the sulfur replaced by a smaller atom, or that have modified or acyclic ring systems may retain activity against lamivudine-resistant mutants, consistent with the observed susceptibility of these mutants to adefovir, lobucavir, and penciclovir in vitro and adefovir in vivo.

Project description:BackgroundThe 2-drug regimen dolutegravir + lamivudine was noninferior to dolutegravir + tenofovir disoproxil fumarate/emtricitabine in achieving HIV-1 RNA <50 copies/mL in treatment-naive adults in the 48-week primary analysis of the GEMINI trials. We present results from the prespecified 96-week secondary analyses.SettingOne hundred eighty-seven centers in 21 countries.MethodsGEMINI-1 and GEMINI-2 are identical, double-blind phase III studies. Participants with screening HIV-1 RNA ?500,000 copies/mL were randomized 1:1 to once-daily dolutegravir + lamivudine or dolutegravir + tenofovir disoproxil fumarate/emtricitabine.ResultsAt week 96, dolutegravir + lamivudine (N = 716) was noninferior to dolutegravir + tenofovir disoproxil fumarate/emtricitabine (N = 717) in achieving HIV-1 RNA <50 copies/mL (Snapshot algorithm; -10% noninferiority margin) in the pooled analysis (proportion of responders, 86.0% vs 89.5%, respectively; adjusted treatment difference [95% CI], -3.4% [-6.7 to 0.0007]), GEMINI-1 (-4.9% [-9.8 to 0.03]), and GEMINI-2 (-1.8% [-6.4 to 2.7]). Proportions of participants in the HIV-1 RNA ?50 copies/mL Snapshot category were largely unchanged from week 48 to 96. Eleven participants taking dolutegravir + lamivudine and 7 taking dolutegravir + tenofovir disoproxil fumarate/emtricitabine met confirmed virologic withdrawal criteria through week 96; none had treatment-emergent resistance mutations. Dolutegravir + lamivudine had a lower rate of drug-related adverse events than dolutegravir + tenofovir disoproxil fumarate/emtricitabine (19.6% vs 25.0%; relative risk ratio, 0.78; 95% CI: 0.64 to 0.95). Renal and bone biomarker changes favored dolutegravir + lamivudine.ConclusionsConsistent with 48-week data, dolutegravir + lamivudine demonstrated long-term, noninferior efficacy vs dolutegravir + tenofovir disoproxil fumarate/emtricitabine without increased risk of treatment-emergent resistance, supporting its use in treatment-naive HIV-1-infected individuals.