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Study Overview
Objective. To evaluate the efficacy and safety of a once-daily 2-drug antiretroviral (ARV) regimen, dolutegravir plus lamivudine, for the treatment of HIV-1 infection in adults naive to antiretroviral therapy (ART).
Design. GEMINI-1 and GEMINI-2 were 2 identically designed multicenter, double-blind, randomized, noninferiority, phase 3 clinical trials conducted between July 18, 2016 and March 31, 2017. Participants were stratified to receive 1 of 2 once-daily HIV regimens: the study regimen, consisting of once-daily dolutegravir 50 mg plus lamivudine 300 mg, or the standard-of-care regimen, consisting of once-daily dolutegravir 50 mg plus tenofovir disoproxil fumarate (TDF) 300 mg plus emtricitabine 200 mg. While this article presents results at week 48, both trials are scheduled to evaluate participants up to week 148 in an attempt to evaluate long-term efficacy and safety.
Setting and participants. Eligible participants had to be aged 18 years or older with treatment-naive HIV-1 infection. Women were eligible if they were not (1) pregnant, (2) lactating, or (3) of reproductive potential, defined by various means, including tubal ligation, hysterectomy, postmenopausal, and the use of highly effective contraception. Initially, eligibility screening restricted participation to those with viral loads between 1000 and 100,000 copies/mL. However, the upper limit was later increased to 500,000 copies/mL based on an independent review of results from other clinical trials1,2 evaluating dual therapy with dolutegravir and lamivudine, which indicated efficacy in patients with viral loads up to 500,000.3-5
Notable exclusion criteria included: (1) major mutations to nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors; (2) evidence of hepatitis B infection; (3) hepatitis C infection with anticipation of initiating treatment within 48 weeks of study enrollment; and (4) stage 3 HIV disease, per Centers for Disease Control and Prevention criteria, with the exception of cutaneous Kaposi sarcoma and CD4 cell counts < 200 cells/mL.
Main outcome measures. The primary endpoint was demonstration of noninferiority of the 2-drug ARV regimen through assessment of the proportion of participants who achieved virologic suppression at week 48 in the intent-to-treat-exposed population. For the purposes of this study, virologic suppression was defined as having fewer than 50 copies of HIV-1 RNA per mL at week 48. For evaluation of safety and toxicity concerns, renal and bone biomarkers were assessed at study entry and at weeks 24 and 48. In addition, participants who met virological withdrawal criteria were evaluated for integrase strand transfer inhibitor mutations. Virological withdrawal was defined as the presence of 1 of the following: (1) HIV RNA > 200 copies/mL at week 24, (2) HIV RNA > 200 copies/mL after previous HIV RNA < 200 copies/mL (confirmed rebound), and (3) a < 1 log10 copies/mL decrease from baseline (unless already < 200 copies/mL).
Main results. GEMINI-1 and GEMINI-2 randomized a combined total of 1441 participants to receive either the once-daily 2-drug ARV regimen (dolutegravir and lamivudine, n = 719) or the once-daily 3-drug ARV regimen (dolutegravir, TDF, and emtricitabine, n = 722). Of the 533 participants who did not meet inclusion criteria, the predominant reasons for exclusion were either having preexisting major viral resistance mutations (n = 246) or viral loads outside the range of 1000 to 500,000 copies/mL (n = 133).
Baseline demographic and clinical characteristics were similar between both groups. The median age was 33 years (10% were over 50 years of age), and participants were mostly male (85%) and white (68%). Baseline HIV RNA counts of > 100,000 copies/mL were found in 293 participants (20%), and 188 (8%) participants had CD4 counts of ≤ 200 cells/mL.
Noninferiority of the once-daily 2-drug versus the once-daily 3-drug ARV regimen was demonstrated in both the GEMINI-1 and GEMINI-2 trials for the intent-to-treat-exposed population. In GEMINI-1, 90% (n = 320) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 93% (n = 332) in the 3-drug ARV group (no statistically significant difference). In GEMINI-2, 93% (n =335 ) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 94% (n = 337) in the 3-drug ARV group (no statistically significant difference).
A subgroup analysis found no significant impact of baseline HIV RNA (> 100,000 compared to ≤ 100,000 copies/mL) on achieving virologic suppression at week 48. However, a subgroup analysis did find that participants with CD4 counts < 200 copies/mL had a reduced response in the once-daily 2-drug versus 3-drug ARV regimen for achieving virologic response at week 48 (79% versus 93%, respectively).
Overall, 10 participants met virological withdrawal criteria during the study period, and 4 of these were on the 2-drug ARV regimen. For these 10 participants, genotypic testing did not find emergence of resistance to either nucleoside reverse transcriptase or integrase strand transfer inhibitors.
Regarding renal biomarkers, increases of both serum creatinine and urinary excretion of protein creatinine were significantly greater in the 3-drug ARV group. Also, biomarkers indicating increased bone turnover were elevated in both groups, but the degree of elevation was significantly lower in the 2-drug ARV regimen cohort. It is unclear whether these findings reflect an increased or decreased risk of developing osteopenia or osteoporosis in the 2 study groups.
Conclusion. The once-daily 2-drug ARV regimen dolutegravir and lamivudine is noninferior to the guideline-recommended once-daily 3-drug ARV regimen dolutegravir, TDF, and emtricitabine at achieving viral suppression in ART-naive HIV-1 infected individuals with HIV RNA counts < 500,000 copies/mL. However, the efficacy of this ARV regimen may be compromised in individuals with CD4 counts < 200 cells/mL.
Commentary
Currently, the mainstay of HIV pharmacotherapy is a 3-drug regimen consisting of 2 nucleoside reverse transcriptase inhibitors in combination with 1 drug from another class, with an integrase strand transfer inhibitor being the preferred third drug.6 Despite the improved tolerability of contemporary ARVs, there remains concern among HIV practitioners regarding potential toxicities associated with cumulative drug exposure, specifically related to nucleoside reverse transcriptase inhibitors. As a result, there has been much interest in evaluating 2-drug ARV regimens for HIV treatment in order to reduce overall drug exposure.7-10
The 48-week results of the GEMINI-1 and GEMINI-2 trials, published in early 2019, further expand our understanding regarding the efficacy and safety of 2-drug regimens in HIV treatment. These identically designed studies evaluated once-daily dolutegravir and lamivudine for HIV in a treatment-naive population. This goes a step further than the SWORD-1 and SWORD-2 trials, which evaluated once-daily dolutegravir and rilpivirine as a step-down therapy for virologically suppressed individuals and led to the U.S. Food and Drug Administration (FDA) approval of the single-tablet combination regimen dolutegravir/rilpivirine (Juluca).10 Therefore, whereas the SWORD trials evaluated a 2-drug regimen for maintenance of virologic suppression, the GEMINI trials assessed whether a 2-drug regimen can both achieve and maintain virologic suppression.
The results of the GEMINI trials are promising for a future direction in HIV care. The rates of virologic suppression achieved in these trials are comparable to those seen in the SWORD trials.10 Furthermore, the virologic response seen in the GEMINI trials is comparable to that seen in similar trials that evaluated a 3-drug ARV regimen consisting of an integrase strand transfer inhibitor–based backbone in ART-naive individuals.11,12
A major confounder to the design of this trial was that it included TDF as one of the components in the comparator arm, an agent that has already been demonstrated to have detrimental effects on both renal and bone health.13,14 Additionally, the bone biomarker results were inconclusive, and the agents’ effects on bone would have been better demonstrated through bone mineral density testing, as had been done in prior trials.
Applications for Clinical Practice
Given the recent FDA approval of the single-tablet combination regimen dolutegravir and lamivudine (Dovato), this once-daily 2-drug ARV regimen will begin making its way into clinical practice for certain patients. Prior to starting this regimen, hepatitis B infection first must be ruled out due to poor efficacy of lamivudine monotherapy for management of chronic hepatitis B infection.15 Additionally, baseline genotype testing should be performed prior to starting this ART given that approximately 10% of newly diagnosed HIV patients have baseline resistance mutations.16 Obtaining rapid genotype testing may be difficult to accomplish in low-resource settings where such testing is not readily available. Finally, this approach may not be applicable to those presenting with acute HIV infection, in whom viral loads are often in the millions of copies per mL. It is likely that dolutegravir/lamivudine could assume a role similar to that of dolutegravir/rilpivirine, in which patients who present with acute HIV step down to a 2-drug regimen once their viral loads have either dropped below 500,000 copies/mL or have already been suppressed.
—Evan K. Mallory, PharmD, Banner-University Medical Center Tucson, and Norman L. Beatty, MD, University of Arizona College of Medicine, Tucson, AZ
1. Cahn P, Rolón MJ, Figueroa MI, et al. Dolutegravir-lamivudine as initial therapy in HIV-1 infected, ARV-naive patients, 48-week results of the PADDLE (Pilot Antiretroviral Design with Dolutegravir LamivudinE) study. J Int AIDS Soc. 2017;20:21678.
2. Taiwo BO, Zheng L, Stefanescu A, et al. ACTG A5353: a pilot study of dolutegravir plus lamivudine for initial treatment of human immunodeficiency virus-1 (HIV-1)-infected participants eith HIV-1 RNA <500000 vopies/mL. Clin Infect Dis. 2018;66:1689-1697.
3. Min S, Sloan L, DeJesus E, et al. Antiviral activity, safety, and pharmacokinetics/pharmacodynamics of dolutegravir as 10-day monotherapy in HIV-1-infected adults. AIDS. 2011;25:1737-1745.
4. Eron JJ, Benoit SL, Jemsek J, et al. Treatment with lamivudine, zidovudine, or both in HIV-positive patients with 200 to 500 CD4+ cells per cubic millimeter. North American HIV Working Party. N Engl J Med. 1995;333:1662-1669.
5. Kuritzkes DR, Quinn JB, Benoit SL, et al. Drug resistance and virologic response in NUCA 3001, a randomized trial of lamivudine (3TC) versus zidovudine (ZDV) versus ZDV plus 3TC in previously untreated patients. AIDS. 1996;10:975-981.
6. Department of Health and Human Services. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. http://aidsinfo.nih.gov/contentfiles/lvguidelines/AdultandAdolescentGL.pdf. Accessed April 1, 2019.
7. Riddler SA, Haubrich R, DiRienzo AG, et al. Class-sparing regimens for initial treatment of HIV-1 infection. N Engl J Med. 2008;358:2095-2106.
8. Reynes J, Lawal A, Pulido F, et al. Examination of noninferiority, safety, and tolerability of lopinavir/ritonavir and raltegravir compared with lopinavir/ritonavir and tenofovir/ emtricitabine in antiretroviral-naïve subjects: the progress study, 48-week results. HIV Clin Trials. 2011;12:255-267.
9. Cahn P, Andrade-Villanueva J, Arribas JR, et al. Dual therapy with lopinavir and ritonavir plus lamivudine versus triple therapy with lopinavir and ritonavir plus two nucleoside reverse transcriptase inhibitors in antiretroviral-therapy-naive adults with HIV-1 infection: 48 week results of the randomised, open label, non-inferiority GARDEL trial. Lancet Infect Dis. 2014;14:572-580.
10. Llibre JM, Hung CC, Brinson C, et al. Efficacy, safety, and tolerability of dolutegravir-rilpivirine for the maintenance of virological suppression in adults with HIV-1: phase 3, randomised, non-inferiority SWORD-1 and SWORD-2 studies. Lancet. 2018;391:839-849.
11. Walmsley SL, Antela A, Clumeck N, et al. Dolutegravir plus abacavir-lamivudine for the treatment of HIV-1 infection. N Engl J Med. 2013;369:1807-1818.
12. Sax PE, Wohl D, Yin MT, et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. Lancet. 2015;385:2606-2615.
13. Mulligan K, Glidden DV, Anderson PL, et al. Effects of emtricitabine/tenofovir on bone mineral density in HIV-negative persons in a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2015;61:572-580.
14. Cooper RD, Wiebe N, Smith N, et al. Systematic review and meta-analysis: renal safety of tenofovir disoproxil fumarate in HIV-infected patients. Clin Infect Dis. 2010;51:496-505.
15. Kim D, Wheeler W, Ziebell R, et al. Prevalence of antiretroviral drug resistance among newly diagnosed HIV-1 infected persons, United States, 2007. 17th Conference on Retroviruses & Opportunistic Infections; San Francisco, CA: 2010. Feb 16-19. Abstract 580.
16. Terrault NA, Lok ASF, McMahon BJ, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018;67:1560-1599.
Study Overview
Objective. To evaluate the efficacy and safety of a once-daily 2-drug antiretroviral (ARV) regimen, dolutegravir plus lamivudine, for the treatment of HIV-1 infection in adults naive to antiretroviral therapy (ART).
Design. GEMINI-1 and GEMINI-2 were 2 identically designed multicenter, double-blind, randomized, noninferiority, phase 3 clinical trials conducted between July 18, 2016 and March 31, 2017. Participants were stratified to receive 1 of 2 once-daily HIV regimens: the study regimen, consisting of once-daily dolutegravir 50 mg plus lamivudine 300 mg, or the standard-of-care regimen, consisting of once-daily dolutegravir 50 mg plus tenofovir disoproxil fumarate (TDF) 300 mg plus emtricitabine 200 mg. While this article presents results at week 48, both trials are scheduled to evaluate participants up to week 148 in an attempt to evaluate long-term efficacy and safety.
Setting and participants. Eligible participants had to be aged 18 years or older with treatment-naive HIV-1 infection. Women were eligible if they were not (1) pregnant, (2) lactating, or (3) of reproductive potential, defined by various means, including tubal ligation, hysterectomy, postmenopausal, and the use of highly effective contraception. Initially, eligibility screening restricted participation to those with viral loads between 1000 and 100,000 copies/mL. However, the upper limit was later increased to 500,000 copies/mL based on an independent review of results from other clinical trials1,2 evaluating dual therapy with dolutegravir and lamivudine, which indicated efficacy in patients with viral loads up to 500,000.3-5
Notable exclusion criteria included: (1) major mutations to nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors; (2) evidence of hepatitis B infection; (3) hepatitis C infection with anticipation of initiating treatment within 48 weeks of study enrollment; and (4) stage 3 HIV disease, per Centers for Disease Control and Prevention criteria, with the exception of cutaneous Kaposi sarcoma and CD4 cell counts < 200 cells/mL.
Main outcome measures. The primary endpoint was demonstration of noninferiority of the 2-drug ARV regimen through assessment of the proportion of participants who achieved virologic suppression at week 48 in the intent-to-treat-exposed population. For the purposes of this study, virologic suppression was defined as having fewer than 50 copies of HIV-1 RNA per mL at week 48. For evaluation of safety and toxicity concerns, renal and bone biomarkers were assessed at study entry and at weeks 24 and 48. In addition, participants who met virological withdrawal criteria were evaluated for integrase strand transfer inhibitor mutations. Virological withdrawal was defined as the presence of 1 of the following: (1) HIV RNA > 200 copies/mL at week 24, (2) HIV RNA > 200 copies/mL after previous HIV RNA < 200 copies/mL (confirmed rebound), and (3) a < 1 log10 copies/mL decrease from baseline (unless already < 200 copies/mL).
Main results. GEMINI-1 and GEMINI-2 randomized a combined total of 1441 participants to receive either the once-daily 2-drug ARV regimen (dolutegravir and lamivudine, n = 719) or the once-daily 3-drug ARV regimen (dolutegravir, TDF, and emtricitabine, n = 722). Of the 533 participants who did not meet inclusion criteria, the predominant reasons for exclusion were either having preexisting major viral resistance mutations (n = 246) or viral loads outside the range of 1000 to 500,000 copies/mL (n = 133).
Baseline demographic and clinical characteristics were similar between both groups. The median age was 33 years (10% were over 50 years of age), and participants were mostly male (85%) and white (68%). Baseline HIV RNA counts of > 100,000 copies/mL were found in 293 participants (20%), and 188 (8%) participants had CD4 counts of ≤ 200 cells/mL.
Noninferiority of the once-daily 2-drug versus the once-daily 3-drug ARV regimen was demonstrated in both the GEMINI-1 and GEMINI-2 trials for the intent-to-treat-exposed population. In GEMINI-1, 90% (n = 320) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 93% (n = 332) in the 3-drug ARV group (no statistically significant difference). In GEMINI-2, 93% (n =335 ) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 94% (n = 337) in the 3-drug ARV group (no statistically significant difference).
A subgroup analysis found no significant impact of baseline HIV RNA (> 100,000 compared to ≤ 100,000 copies/mL) on achieving virologic suppression at week 48. However, a subgroup analysis did find that participants with CD4 counts < 200 copies/mL had a reduced response in the once-daily 2-drug versus 3-drug ARV regimen for achieving virologic response at week 48 (79% versus 93%, respectively).
Overall, 10 participants met virological withdrawal criteria during the study period, and 4 of these were on the 2-drug ARV regimen. For these 10 participants, genotypic testing did not find emergence of resistance to either nucleoside reverse transcriptase or integrase strand transfer inhibitors.
Regarding renal biomarkers, increases of both serum creatinine and urinary excretion of protein creatinine were significantly greater in the 3-drug ARV group. Also, biomarkers indicating increased bone turnover were elevated in both groups, but the degree of elevation was significantly lower in the 2-drug ARV regimen cohort. It is unclear whether these findings reflect an increased or decreased risk of developing osteopenia or osteoporosis in the 2 study groups.
Conclusion. The once-daily 2-drug ARV regimen dolutegravir and lamivudine is noninferior to the guideline-recommended once-daily 3-drug ARV regimen dolutegravir, TDF, and emtricitabine at achieving viral suppression in ART-naive HIV-1 infected individuals with HIV RNA counts < 500,000 copies/mL. However, the efficacy of this ARV regimen may be compromised in individuals with CD4 counts < 200 cells/mL.
Commentary
Currently, the mainstay of HIV pharmacotherapy is a 3-drug regimen consisting of 2 nucleoside reverse transcriptase inhibitors in combination with 1 drug from another class, with an integrase strand transfer inhibitor being the preferred third drug.6 Despite the improved tolerability of contemporary ARVs, there remains concern among HIV practitioners regarding potential toxicities associated with cumulative drug exposure, specifically related to nucleoside reverse transcriptase inhibitors. As a result, there has been much interest in evaluating 2-drug ARV regimens for HIV treatment in order to reduce overall drug exposure.7-10
The 48-week results of the GEMINI-1 and GEMINI-2 trials, published in early 2019, further expand our understanding regarding the efficacy and safety of 2-drug regimens in HIV treatment. These identically designed studies evaluated once-daily dolutegravir and lamivudine for HIV in a treatment-naive population. This goes a step further than the SWORD-1 and SWORD-2 trials, which evaluated once-daily dolutegravir and rilpivirine as a step-down therapy for virologically suppressed individuals and led to the U.S. Food and Drug Administration (FDA) approval of the single-tablet combination regimen dolutegravir/rilpivirine (Juluca).10 Therefore, whereas the SWORD trials evaluated a 2-drug regimen for maintenance of virologic suppression, the GEMINI trials assessed whether a 2-drug regimen can both achieve and maintain virologic suppression.
The results of the GEMINI trials are promising for a future direction in HIV care. The rates of virologic suppression achieved in these trials are comparable to those seen in the SWORD trials.10 Furthermore, the virologic response seen in the GEMINI trials is comparable to that seen in similar trials that evaluated a 3-drug ARV regimen consisting of an integrase strand transfer inhibitor–based backbone in ART-naive individuals.11,12
A major confounder to the design of this trial was that it included TDF as one of the components in the comparator arm, an agent that has already been demonstrated to have detrimental effects on both renal and bone health.13,14 Additionally, the bone biomarker results were inconclusive, and the agents’ effects on bone would have been better demonstrated through bone mineral density testing, as had been done in prior trials.
Applications for Clinical Practice
Given the recent FDA approval of the single-tablet combination regimen dolutegravir and lamivudine (Dovato), this once-daily 2-drug ARV regimen will begin making its way into clinical practice for certain patients. Prior to starting this regimen, hepatitis B infection first must be ruled out due to poor efficacy of lamivudine monotherapy for management of chronic hepatitis B infection.15 Additionally, baseline genotype testing should be performed prior to starting this ART given that approximately 10% of newly diagnosed HIV patients have baseline resistance mutations.16 Obtaining rapid genotype testing may be difficult to accomplish in low-resource settings where such testing is not readily available. Finally, this approach may not be applicable to those presenting with acute HIV infection, in whom viral loads are often in the millions of copies per mL. It is likely that dolutegravir/lamivudine could assume a role similar to that of dolutegravir/rilpivirine, in which patients who present with acute HIV step down to a 2-drug regimen once their viral loads have either dropped below 500,000 copies/mL or have already been suppressed.
—Evan K. Mallory, PharmD, Banner-University Medical Center Tucson, and Norman L. Beatty, MD, University of Arizona College of Medicine, Tucson, AZ
Study Overview
Objective. To evaluate the efficacy and safety of a once-daily 2-drug antiretroviral (ARV) regimen, dolutegravir plus lamivudine, for the treatment of HIV-1 infection in adults naive to antiretroviral therapy (ART).
Design. GEMINI-1 and GEMINI-2 were 2 identically designed multicenter, double-blind, randomized, noninferiority, phase 3 clinical trials conducted between July 18, 2016 and March 31, 2017. Participants were stratified to receive 1 of 2 once-daily HIV regimens: the study regimen, consisting of once-daily dolutegravir 50 mg plus lamivudine 300 mg, or the standard-of-care regimen, consisting of once-daily dolutegravir 50 mg plus tenofovir disoproxil fumarate (TDF) 300 mg plus emtricitabine 200 mg. While this article presents results at week 48, both trials are scheduled to evaluate participants up to week 148 in an attempt to evaluate long-term efficacy and safety.
Setting and participants. Eligible participants had to be aged 18 years or older with treatment-naive HIV-1 infection. Women were eligible if they were not (1) pregnant, (2) lactating, or (3) of reproductive potential, defined by various means, including tubal ligation, hysterectomy, postmenopausal, and the use of highly effective contraception. Initially, eligibility screening restricted participation to those with viral loads between 1000 and 100,000 copies/mL. However, the upper limit was later increased to 500,000 copies/mL based on an independent review of results from other clinical trials1,2 evaluating dual therapy with dolutegravir and lamivudine, which indicated efficacy in patients with viral loads up to 500,000.3-5
Notable exclusion criteria included: (1) major mutations to nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors; (2) evidence of hepatitis B infection; (3) hepatitis C infection with anticipation of initiating treatment within 48 weeks of study enrollment; and (4) stage 3 HIV disease, per Centers for Disease Control and Prevention criteria, with the exception of cutaneous Kaposi sarcoma and CD4 cell counts < 200 cells/mL.
Main outcome measures. The primary endpoint was demonstration of noninferiority of the 2-drug ARV regimen through assessment of the proportion of participants who achieved virologic suppression at week 48 in the intent-to-treat-exposed population. For the purposes of this study, virologic suppression was defined as having fewer than 50 copies of HIV-1 RNA per mL at week 48. For evaluation of safety and toxicity concerns, renal and bone biomarkers were assessed at study entry and at weeks 24 and 48. In addition, participants who met virological withdrawal criteria were evaluated for integrase strand transfer inhibitor mutations. Virological withdrawal was defined as the presence of 1 of the following: (1) HIV RNA > 200 copies/mL at week 24, (2) HIV RNA > 200 copies/mL after previous HIV RNA < 200 copies/mL (confirmed rebound), and (3) a < 1 log10 copies/mL decrease from baseline (unless already < 200 copies/mL).
Main results. GEMINI-1 and GEMINI-2 randomized a combined total of 1441 participants to receive either the once-daily 2-drug ARV regimen (dolutegravir and lamivudine, n = 719) or the once-daily 3-drug ARV regimen (dolutegravir, TDF, and emtricitabine, n = 722). Of the 533 participants who did not meet inclusion criteria, the predominant reasons for exclusion were either having preexisting major viral resistance mutations (n = 246) or viral loads outside the range of 1000 to 500,000 copies/mL (n = 133).
Baseline demographic and clinical characteristics were similar between both groups. The median age was 33 years (10% were over 50 years of age), and participants were mostly male (85%) and white (68%). Baseline HIV RNA counts of > 100,000 copies/mL were found in 293 participants (20%), and 188 (8%) participants had CD4 counts of ≤ 200 cells/mL.
Noninferiority of the once-daily 2-drug versus the once-daily 3-drug ARV regimen was demonstrated in both the GEMINI-1 and GEMINI-2 trials for the intent-to-treat-exposed population. In GEMINI-1, 90% (n = 320) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 93% (n = 332) in the 3-drug ARV group (no statistically significant difference). In GEMINI-2, 93% (n =335 ) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 94% (n = 337) in the 3-drug ARV group (no statistically significant difference).
A subgroup analysis found no significant impact of baseline HIV RNA (> 100,000 compared to ≤ 100,000 copies/mL) on achieving virologic suppression at week 48. However, a subgroup analysis did find that participants with CD4 counts < 200 copies/mL had a reduced response in the once-daily 2-drug versus 3-drug ARV regimen for achieving virologic response at week 48 (79% versus 93%, respectively).
Overall, 10 participants met virological withdrawal criteria during the study period, and 4 of these were on the 2-drug ARV regimen. For these 10 participants, genotypic testing did not find emergence of resistance to either nucleoside reverse transcriptase or integrase strand transfer inhibitors.
Regarding renal biomarkers, increases of both serum creatinine and urinary excretion of protein creatinine were significantly greater in the 3-drug ARV group. Also, biomarkers indicating increased bone turnover were elevated in both groups, but the degree of elevation was significantly lower in the 2-drug ARV regimen cohort. It is unclear whether these findings reflect an increased or decreased risk of developing osteopenia or osteoporosis in the 2 study groups.
Conclusion. The once-daily 2-drug ARV regimen dolutegravir and lamivudine is noninferior to the guideline-recommended once-daily 3-drug ARV regimen dolutegravir, TDF, and emtricitabine at achieving viral suppression in ART-naive HIV-1 infected individuals with HIV RNA counts < 500,000 copies/mL. However, the efficacy of this ARV regimen may be compromised in individuals with CD4 counts < 200 cells/mL.
Commentary
Currently, the mainstay of HIV pharmacotherapy is a 3-drug regimen consisting of 2 nucleoside reverse transcriptase inhibitors in combination with 1 drug from another class, with an integrase strand transfer inhibitor being the preferred third drug.6 Despite the improved tolerability of contemporary ARVs, there remains concern among HIV practitioners regarding potential toxicities associated with cumulative drug exposure, specifically related to nucleoside reverse transcriptase inhibitors. As a result, there has been much interest in evaluating 2-drug ARV regimens for HIV treatment in order to reduce overall drug exposure.7-10
The 48-week results of the GEMINI-1 and GEMINI-2 trials, published in early 2019, further expand our understanding regarding the efficacy and safety of 2-drug regimens in HIV treatment. These identically designed studies evaluated once-daily dolutegravir and lamivudine for HIV in a treatment-naive population. This goes a step further than the SWORD-1 and SWORD-2 trials, which evaluated once-daily dolutegravir and rilpivirine as a step-down therapy for virologically suppressed individuals and led to the U.S. Food and Drug Administration (FDA) approval of the single-tablet combination regimen dolutegravir/rilpivirine (Juluca).10 Therefore, whereas the SWORD trials evaluated a 2-drug regimen for maintenance of virologic suppression, the GEMINI trials assessed whether a 2-drug regimen can both achieve and maintain virologic suppression.
The results of the GEMINI trials are promising for a future direction in HIV care. The rates of virologic suppression achieved in these trials are comparable to those seen in the SWORD trials.10 Furthermore, the virologic response seen in the GEMINI trials is comparable to that seen in similar trials that evaluated a 3-drug ARV regimen consisting of an integrase strand transfer inhibitor–based backbone in ART-naive individuals.11,12
A major confounder to the design of this trial was that it included TDF as one of the components in the comparator arm, an agent that has already been demonstrated to have detrimental effects on both renal and bone health.13,14 Additionally, the bone biomarker results were inconclusive, and the agents’ effects on bone would have been better demonstrated through bone mineral density testing, as had been done in prior trials.
Applications for Clinical Practice
Given the recent FDA approval of the single-tablet combination regimen dolutegravir and lamivudine (Dovato), this once-daily 2-drug ARV regimen will begin making its way into clinical practice for certain patients. Prior to starting this regimen, hepatitis B infection first must be ruled out due to poor efficacy of lamivudine monotherapy for management of chronic hepatitis B infection.15 Additionally, baseline genotype testing should be performed prior to starting this ART given that approximately 10% of newly diagnosed HIV patients have baseline resistance mutations.16 Obtaining rapid genotype testing may be difficult to accomplish in low-resource settings where such testing is not readily available. Finally, this approach may not be applicable to those presenting with acute HIV infection, in whom viral loads are often in the millions of copies per mL. It is likely that dolutegravir/lamivudine could assume a role similar to that of dolutegravir/rilpivirine, in which patients who present with acute HIV step down to a 2-drug regimen once their viral loads have either dropped below 500,000 copies/mL or have already been suppressed.
—Evan K. Mallory, PharmD, Banner-University Medical Center Tucson, and Norman L. Beatty, MD, University of Arizona College of Medicine, Tucson, AZ
1. Cahn P, Rolón MJ, Figueroa MI, et al. Dolutegravir-lamivudine as initial therapy in HIV-1 infected, ARV-naive patients, 48-week results of the PADDLE (Pilot Antiretroviral Design with Dolutegravir LamivudinE) study. J Int AIDS Soc. 2017;20:21678.
2. Taiwo BO, Zheng L, Stefanescu A, et al. ACTG A5353: a pilot study of dolutegravir plus lamivudine for initial treatment of human immunodeficiency virus-1 (HIV-1)-infected participants eith HIV-1 RNA <500000 vopies/mL. Clin Infect Dis. 2018;66:1689-1697.
3. Min S, Sloan L, DeJesus E, et al. Antiviral activity, safety, and pharmacokinetics/pharmacodynamics of dolutegravir as 10-day monotherapy in HIV-1-infected adults. AIDS. 2011;25:1737-1745.
4. Eron JJ, Benoit SL, Jemsek J, et al. Treatment with lamivudine, zidovudine, or both in HIV-positive patients with 200 to 500 CD4+ cells per cubic millimeter. North American HIV Working Party. N Engl J Med. 1995;333:1662-1669.
5. Kuritzkes DR, Quinn JB, Benoit SL, et al. Drug resistance and virologic response in NUCA 3001, a randomized trial of lamivudine (3TC) versus zidovudine (ZDV) versus ZDV plus 3TC in previously untreated patients. AIDS. 1996;10:975-981.
6. Department of Health and Human Services. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. http://aidsinfo.nih.gov/contentfiles/lvguidelines/AdultandAdolescentGL.pdf. Accessed April 1, 2019.
7. Riddler SA, Haubrich R, DiRienzo AG, et al. Class-sparing regimens for initial treatment of HIV-1 infection. N Engl J Med. 2008;358:2095-2106.
8. Reynes J, Lawal A, Pulido F, et al. Examination of noninferiority, safety, and tolerability of lopinavir/ritonavir and raltegravir compared with lopinavir/ritonavir and tenofovir/ emtricitabine in antiretroviral-naïve subjects: the progress study, 48-week results. HIV Clin Trials. 2011;12:255-267.
9. Cahn P, Andrade-Villanueva J, Arribas JR, et al. Dual therapy with lopinavir and ritonavir plus lamivudine versus triple therapy with lopinavir and ritonavir plus two nucleoside reverse transcriptase inhibitors in antiretroviral-therapy-naive adults with HIV-1 infection: 48 week results of the randomised, open label, non-inferiority GARDEL trial. Lancet Infect Dis. 2014;14:572-580.
10. Llibre JM, Hung CC, Brinson C, et al. Efficacy, safety, and tolerability of dolutegravir-rilpivirine for the maintenance of virological suppression in adults with HIV-1: phase 3, randomised, non-inferiority SWORD-1 and SWORD-2 studies. Lancet. 2018;391:839-849.
11. Walmsley SL, Antela A, Clumeck N, et al. Dolutegravir plus abacavir-lamivudine for the treatment of HIV-1 infection. N Engl J Med. 2013;369:1807-1818.
12. Sax PE, Wohl D, Yin MT, et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. Lancet. 2015;385:2606-2615.
13. Mulligan K, Glidden DV, Anderson PL, et al. Effects of emtricitabine/tenofovir on bone mineral density in HIV-negative persons in a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2015;61:572-580.
14. Cooper RD, Wiebe N, Smith N, et al. Systematic review and meta-analysis: renal safety of tenofovir disoproxil fumarate in HIV-infected patients. Clin Infect Dis. 2010;51:496-505.
15. Kim D, Wheeler W, Ziebell R, et al. Prevalence of antiretroviral drug resistance among newly diagnosed HIV-1 infected persons, United States, 2007. 17th Conference on Retroviruses & Opportunistic Infections; San Francisco, CA: 2010. Feb 16-19. Abstract 580.
16. Terrault NA, Lok ASF, McMahon BJ, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018;67:1560-1599.
1. Cahn P, Rolón MJ, Figueroa MI, et al. Dolutegravir-lamivudine as initial therapy in HIV-1 infected, ARV-naive patients, 48-week results of the PADDLE (Pilot Antiretroviral Design with Dolutegravir LamivudinE) study. J Int AIDS Soc. 2017;20:21678.
2. Taiwo BO, Zheng L, Stefanescu A, et al. ACTG A5353: a pilot study of dolutegravir plus lamivudine for initial treatment of human immunodeficiency virus-1 (HIV-1)-infected participants eith HIV-1 RNA <500000 vopies/mL. Clin Infect Dis. 2018;66:1689-1697.
3. Min S, Sloan L, DeJesus E, et al. Antiviral activity, safety, and pharmacokinetics/pharmacodynamics of dolutegravir as 10-day monotherapy in HIV-1-infected adults. AIDS. 2011;25:1737-1745.
4. Eron JJ, Benoit SL, Jemsek J, et al. Treatment with lamivudine, zidovudine, or both in HIV-positive patients with 200 to 500 CD4+ cells per cubic millimeter. North American HIV Working Party. N Engl J Med. 1995;333:1662-1669.
5. Kuritzkes DR, Quinn JB, Benoit SL, et al. Drug resistance and virologic response in NUCA 3001, a randomized trial of lamivudine (3TC) versus zidovudine (ZDV) versus ZDV plus 3TC in previously untreated patients. AIDS. 1996;10:975-981.
6. Department of Health and Human Services. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. http://aidsinfo.nih.gov/contentfiles/lvguidelines/AdultandAdolescentGL.pdf. Accessed April 1, 2019.
7. Riddler SA, Haubrich R, DiRienzo AG, et al. Class-sparing regimens for initial treatment of HIV-1 infection. N Engl J Med. 2008;358:2095-2106.
8. Reynes J, Lawal A, Pulido F, et al. Examination of noninferiority, safety, and tolerability of lopinavir/ritonavir and raltegravir compared with lopinavir/ritonavir and tenofovir/ emtricitabine in antiretroviral-naïve subjects: the progress study, 48-week results. HIV Clin Trials. 2011;12:255-267.
9. Cahn P, Andrade-Villanueva J, Arribas JR, et al. Dual therapy with lopinavir and ritonavir plus lamivudine versus triple therapy with lopinavir and ritonavir plus two nucleoside reverse transcriptase inhibitors in antiretroviral-therapy-naive adults with HIV-1 infection: 48 week results of the randomised, open label, non-inferiority GARDEL trial. Lancet Infect Dis. 2014;14:572-580.
10. Llibre JM, Hung CC, Brinson C, et al. Efficacy, safety, and tolerability of dolutegravir-rilpivirine for the maintenance of virological suppression in adults with HIV-1: phase 3, randomised, non-inferiority SWORD-1 and SWORD-2 studies. Lancet. 2018;391:839-849.
11. Walmsley SL, Antela A, Clumeck N, et al. Dolutegravir plus abacavir-lamivudine for the treatment of HIV-1 infection. N Engl J Med. 2013;369:1807-1818.
12. Sax PE, Wohl D, Yin MT, et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. Lancet. 2015;385:2606-2615.
13. Mulligan K, Glidden DV, Anderson PL, et al. Effects of emtricitabine/tenofovir on bone mineral density in HIV-negative persons in a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2015;61:572-580.
14. Cooper RD, Wiebe N, Smith N, et al. Systematic review and meta-analysis: renal safety of tenofovir disoproxil fumarate in HIV-infected patients. Clin Infect Dis. 2010;51:496-505.
15. Kim D, Wheeler W, Ziebell R, et al. Prevalence of antiretroviral drug resistance among newly diagnosed HIV-1 infected persons, United States, 2007. 17th Conference on Retroviruses & Opportunistic Infections; San Francisco, CA: 2010. Feb 16-19. Abstract 580.
16. Terrault NA, Lok ASF, McMahon BJ, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018;67:1560-1599.