Switching to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir versus continuation of non-nucleoside reverse transcriptase inhibitor with emtricitabine and tenofovir in virologically suppressed adults with HIV (STRATEGY-NNRTI): 48 week results of a randomised, open-label, phase 3b non-inferiority trial
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The Lancet Infectious Diseases, Early Online Publication, 5 June 2014
Presented at CROI/2014: http://www.natap.org/2014/CROI/croi_81.htm
Anton Pozniak, Martin Markowitz, Anthony Mills, Hans-Juergen Stellbrink, Antonio Antela, Pere Domingo, Pierre-Marie Girard, Keith Henry,
Thai Nguyen, David Piontkowsky, Will Garner, Kirsten White, Bill Guyer
Coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (tenofovir) might be a safe and efficacious switch option for virologically suppressed patients with HIV who have neuropsychiatric side-effects on a non-nucleoside reverse transcriptase inhibitor (NNRTI) or who are on a multitablet NNRTI-containing regimen and want a regimen simplification. We assessed the non-inferiority of such a switch compared with continuation of an NNRTI-containing regimen.
STRATEGY-NNRTI is a 96 week, international, multicentre, randomised, open-label, phase 3b, non-inferiority trial enrolling adults (≥18 years) with HIV-1 and plasma HIV RNA viral load below 50 copies per mL for at least 6 months on an NNRTI plus emtricitabine and tenofovir regimen. With a computer-generated randomisation sequence, we randomly allocated participants (2:1; blocks of six, stratified by efavirenz use at screening) to switch to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir (switch group) or continue the NNRTI plus emtricitabine and tenofovir regimen (no-switch group). Key eligibility criteria included no history of virological failure and an estimated glomerular filtration rate of 70 mL per min or greater. The primary endpoint was the proportion of participants with plasma viral loads below 50 copies per mL at week 48 based on a snapshot algorithm with a non-inferiority margin of 12% (assessed by modified intention to treat). This trial is ongoing and is registered at ClinicalTrials.gov, number NCT01495702.
Between Dec 29, 2011, and Dec 13, 2012, we randomly allocated 439 participants to treatment: 290 participants in the switch group and 143 participants in the no-switch group received treatment and were included in the modified intention-to-treat population. At week 48, 271 (93%) of 290 participants in the switch group and 126 (88%) of 143 participants in the no-switch group maintained plasma viral loads below 50 copies per mL (difference 5·3%, 95% CI -0·5 to 12·0; p=0·066). We detected no treatment-emergent resistance in either group. Safety events leading to discontinuation were uncommon in both groups: six (2%) of 291 participants in the switch group and one (1%) of 143 in the no-switch group.
Coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir seems to be efficacious and well tolerated in virologically suppressed adults with HIV and might be a suitable alternative for patients on an NNRTI with emtricitabine and tenofovir regimen considering a regimen modification or simplification.
HIV treatment guidelines, including those from the US Department of Health and Human Services and the European AIDS Clinical Society, endorse regimen simplification, or pre-emptive switches, in patients with virological suppression to improve treatment adherence, enhance tolerability, and prevent long-term toxicity.1, 2 Patients with HIV on a non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing regimen might be appropriate candidates for treatment modification to a NNRTI-sparing regimen if they have neuropsychiatric side-effects such as anxiety, insomnia, dizziness, and abnormal dreams.3 Additionally, those who are on a multitablet NNRTI-containing regimen might want a simplification to a single-tablet regimen.
Coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (tenofovir), containing the HIV-1 integrase strand transfer inhibitor (INSTI) elvitegravir boosted by the CYP3A4 enzyme-based pharmacokinetic enhancer cobicistat, is efficacious, safe, and well tolerated in antiretroviral-naive adult patients with HIV and is a recommended INSTI-based regimen in the US Department of Health and Human Services and British HIV Association treatment guidelines.4-9 Whether patients with virological suppression on an NNRTI plus emtricitabine and tenofovir regimen who continue to have neuropsychiatric side-effects would have symptom improvement after switching to an INSTI, or whether those on a multitablet NNRTI-based regimen would subsequently have more treatment satisfaction with treatment simplification to a single-tablet regimen, is unknown. We aimed to answer these questions in the STRATEGY-NNRTI trial.
STRATEGY-NNRTI is a phase 3b, randomised, open-label, ongoing study done at 72 sites in Australia, Europe, and North America. Participants eligible for inclusion had HIV-1, were aged 18 years or older, and had a plasma HIV RNA viral load below 50 copies per mL while on a stable regimen consisting of an NNRTI with emtricitabine and tenofovir for at least 6 consecutive months. Participants were on their first or second regimen at randomisation. For patients on their second regimen, we excluded those who had a viral load of 50 copies per mL or higher at the time of change in antiretroviral treatment, and those who had had two consecutive viral load measurements of 50 copies per mL or higher after first achieving a viral load below 50 copies per mL. Participants had to have genotypic testing before starting initial combination antiretroviral treatment with no known resistance to any of the study drugs including the reverse transcriptase resistance mutations Met184 Val/Ile, Lys65Arg, or three or more thymidine analogue-associated mutations that included Met41Leu or Leu210Trp. No historical genotype for the integrase gene was required. Additionally, participants had to have not previously used any approved or investigational INSTI and had to have had an estimated glomerular filtration rate (GFR) of 70 mL per min or greater.
The study was done in accordance with the Declaration of Helsinki. The protocol was reviewed and approved by central or site-specific institutional review boards or ethics committees. All participants gave written informed consent.
Randomisation and masking
We randomly allocated eligible participants (2:1; blocks of six, stratified by efavirenz use at screening) to switch to coformulated elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir 300 mg (INSTI regimen) once daily with food (switch group), or remain on the NNRTI regimen, which also included emtricitabine and tenofovir (no-switch group). We used a computer-generated randomisation schedule and an online interactive voice response system created and managed by Bracket (San Fransisco, CA, USA), which had no further role in the trial. The study design was open-label, which allowed assessment of treatment satisfaction and adherence with a single-tablet versus multitablet regimen, when applicable.
Post-baseline study visits occurred at weeks 4, 8, 12, 24, 36, and 48, after which participants continued treatment with visits every 12 weeks until week 96. Safety was assessed by laboratory tests, physical examinations, and adverse events (recorded by investigators on electronic case report forms). Laboratory analyses included haematological tests, serum chemistry tests, urinalysis, CD4 cell counts, fasting lipid parameters (Covance Laboratories; Indianapolis, IN, USA), and plasma HIV RNA testing (Amplicor HIV-1 Monitor Test [version 1.5]; Roche Diagnostics, Rotkreuz, Switzerland). Virological failure was defined as two consecutive visits with a plasma viral load of 50 copies per mL or higher. We did HIV genotyping and phenotyping of protease, reverse transcriptase, and integrase genes in cases of confirmed virological failure with viral loads of 400 copies per mL or higher at the confirmation visit, with viral load of 400 copies per mL or higher at week 48, or on early discontinuation for any reason, using the PhenoSense GT, PhenoSense Integrase, and GeneSeq Integrase assays (Monogram Biosciences; South San Fransisco, CA, USA). We obtained patient-reported outcomes using health-related quality-of-life questionnaires including the expanded HIV symptom index, Center for Epidemiologic Studies Depression, State-Trait Anxiety Inventory, Short Form 36, visual analogue scale adherence, and HIV treatment satisfaction, administered at baseline and subsequent study visits.
All analyses were prespecified in the protocol and statistical analysis plan. Analyses included all data available after the last enrolled participant had completed the week 48 visit (October 31, 2013) or prematurely discontinued the study drug. We did no interim analysis before week 48. The full analysis set was the modified intention-to-treat population, which consisted of participants randomly allocated to treatment and treated with at least one dose of study drug, excluding those with pre-existing prohibited resistance mutations on their historical genotype.10 Participants in both groups were equally assessed and excluded for violation of this major eligibility criterion.
The primary endpoint was the proportion of participants who maintained viral load below 50 copies per mL at week 48 according to the snapshot algorithm as defined by the US Food and Drug Administration (FDA).11 We also did a per-protocol snapshot sensitivity analysis. The per-protocol population consisted of the modified intention-to-treat population, excluding participants with a protocol violation that met prespecified criteria, such as not having sensitivity to emtricitabine and tenofovir on historical genotype, not having virological suppression at both screening and baseline, not having HIV RNA assessments in the week 48 analysis window for reasons other than discontinuation because of lack of efficacy, and taking protocol-prohibited drugs. A secondary efficacy endpoint was the proportion of participants who maintained viral load below 50 copies per mL at week 48 according to the FDA-defined time to loss of virological response (TLOVR) algorithm.12 Secondary endpoints included change in CD4 cell count, safety, and tolerability of the two regimens through week 96. We assessed rates of virological success and differences by subgroup according to age, sex, race, efavirenz and non-efavirenz NNRTI use at baseline, and number of previous antiretroviral regimens.
In the primary efficacy analysis, non-inferiority would be concluded if the lower bound of a two-sided 95% CI for the difference in proportions (switch group minus no-switch group) of participants who maintained plasma viral load below 50 copies per mL at week 48 was greater than -12%. We calculated the two-sided 95% CI for the difference in percentages of virological success between treatment groups with an unconditional exact method using two inverted one-sided tests with standardised statistics using StatXact (version 8).13 If non-inferiority was established in the primary efficacy analysis and the lower bound of 95% CI was greater than zero, then we would test superiority at the nominal 5% significance level with Fisher's exact test. A sample size of 420 participants provided at least 85% power to establish non-inferiority for the percentage of participants maintaining virological suppression at week 48, with assumed response rates of 82% in both groups, and a non-inferiority margin of 12%. We used nQuery Advisor (version 6.0) to calculate sample sizes.
We summarised all safety data obtained on or after the first dose of study drug up to 30 days after the last dose of study drug with descriptive statistics. We coded adverse events using the Medical Dictionary for Regulatory Activities (version 16.1), and estimated GFR by use of the Cockcroft-Gault method.14 We tested treatment differences for continuous laboratory results using the Wilcoxon Rank Sum test. We used SAS (version 9.2) for all statistical analyses.
Between Dec 29, 2011, and Dec 13, 2012, we screened and randomly allocated 439 participants to treatment (figure 1). At randomisation, 338 (78%) of 434 participants were on a single-tablet regimen and the most common reason for interest in the study given on the enrolment survey (self-administered at screening) was related to side-effects of their current regimen, whereas 80 (83%) of 96 participants on a multitablet NNRTI-containing regimen cited a desire to simplify their current regimen as the reason for their interest in the study. Other reasons for enrolment in the study (patients could give more than one reason) included a desire to contribute to HIV research, access to HIV drugs, and drug dosing preferences. Baseline characteristics were well matched between the two treatment groups (table 1). Most participants were on an efavirenz-containing regimen and on their first regimen at the time of randomisation. We excluded one participant (in the switch group) from the modified intention-to-treat population because they had resistance to study drugs on historical genotype (Asp67Asn, Lys70Arg, Met184Val, Thr215Tyr, and Lys219Gln).
The switch regimen was non-inferior to the no-switch regimen at the week 48 primary endpoint based on the number of participants with viral loads below 50 copies per mL (treatment difference 5·3%, 95% CI -0·5 to 12·0; p=0·066; table 2). Few participants had virological failure at week 48 in either group (table 2). A larger proportion of participants in the no-switch group than in the switch group had no virological data at week 48 (16 [11%] of 143 participants vs 16 [6%] of 290 participants), with the difference driven mainly by participants who withdrew consent but whose last viral load was below 50 copies per mL (table 2).
Virological suppression was high in both groups in the sensitivity per-protocol analysis: 267 (99%) of 269 participants in the switch group and 123 (99%) of 124 in the no-switch group had viral load below 50 copies per mL at week 48 (difference 0·1%, 95% CI -2·1 to 3·5; p=1·00), showing non-inferiority of the switch regimen to the no-switch regimen. A secondary efficacy analysis, based on FDA-defined TLOVR algorithm, showed that 266 (92%) of 290 participants in the switch group and 124 (87%) of 143 participants in the no-switch group responded to treatment at week 48 (difference 5·0%, -1·1% to 12·1; p=0·12). Subgroup analyses according to age, sex, race, efavirenz and non-efavirenz NNRTI use, and number of previous regimens showed high rates of virological success on the switch regimen at week 48 (figure 2).
One participant in each group met the criteria for genotypic resistance testing, but neither had emergent resistance. Both participants remained on study treatment and achieved virological suppression after week 48. We saw no between-group difference in increases from baseline at week 48 in CD4 count: mean 56 cells per μL (SD 147) in the switch group versus 58 cells per μL (179) in the no-switch group.
Adverse events occurred at similar frequencies in both groups and most were grade 1 or 2 in severity (table 3). In analysis of adverse events that occurred in 5% or more of participants in either group, fatigue, cough, headache, and nausea occurred more often in the switch group compared with the no-switch group (table 3). We saw no between-group difference in the occurrence of other adverse events. Most headache and nausea were grade 1 or 2 in severity, occurred by week 4 or week 8, and were transient-none led to discontinuation of study drugs. Rates of headache and nausea were similar between treatment groups by week 12 (figure 3).
Adverse events that led to study drug discontinuation were uncommon in both groups: causes in the switch group were arthralgia, coccydnia, paraesthesia, muscle atrophy, and hypoaesthesia (one patient had all five symptoms), suicide (one), dysgeusia (one), prurigo (one), acquired Fanconi's syndrome (one), and increased blood creatinine (one); the cause in the no-switch group was altered mood (one). The individual with Fanconi's syndrome had laboratory test results suggestive of proximal renal tubulopathy including proteinuria and glycosuria on a tenofovir-containing regimen at screening and baseline visits; his renal function and tubular markers improved to baseline levels after discontinuation of tenofovir. One participant in the switch group died from suicide during the study-the investigator regarded this death as being unrelated to study drug.
Most participants had at least one treatment-emergent laboratory abnormality reported during the study, which were mostly grade 1 or 2 in severity. Grade 3 or 4 laboratory abnormalities were reported for a similar percentage of participants in the switch (28 [10%] of 291 participants) and the no-switch (19 [14%] of 143) groups. Starting at week 4, we saw increases from baseline in serum creatinine concentration that generally stabilised and were non-progressive through week 48 in the switch group (median 11 μmol/L [IQR 4 to 18]); we saw no change between baseline and week 48 in serum creatinine concentrations in the no-switch group (-1 μmol/L, -5 to 6; appendix).
Other than a small decrease in high-density lipoprotein cholesterol in the switch group versus no change in the no-switch group, we saw no changes from baseline at week 48 in fasting lipid concentrations in both groups (appendix). Subgroup analysis showed small decreases from baseline at week 48 in fasting total (p=0·01), low-density lipoprotein (p=0·001), and high-density lipoprotein (p=0·008) cholesterol in participants in the efavirenz switch subgroup versus no changes from baseline in those who continued an efavirenz-containing regimen (appendix). We recorded small increases from baseline at week 48 in low-density lipoprotein cholesterol (p=0·018) and the ratio of total cholesterol to high-density lipoprotein cholesterol (p=0·026) in participants in the non-efavirenz NNRTI switch subgroup (appendix).
Results of the expanded HIV symptom index showed that occurrence of anxiety, insomnia, dizziness, vivid dreams, weird or intense dreams, and nightmares decreased from week 4 to week 48 compared with baseline in particpants who switched from an efavirenz-containing regimen to the INSTI regimen (appendix); whereas we saw no changes in these symptoms in participants who switched from a non-efavirenz NNRTI nor in those continuing an efavirenz-containing regimen.
Rates of the other HIV symptoms did not increase or decrease compared with baseline, from week 4 to week 48, in either group (data not shown). Participants in the efavirenz switch subgroup had higher treatment satisfaction scores than did those who continued an efavirenz-containing regimen (range -30 to 30) at week 4 (mean 17·6 [SD 11·9] vs 11·7 [12·9]; p=0·0005) and week 24 (21·3 [10·3] vs 13·7 [12·6]; p <0·0001). Patient-reported outcomes from other questionnaires including Center for Epidemiologic Studies Depression, State-Trait Anxiety Inventory, Short Form 36, and visual analogue scale adherence were generally favourable in both groups, unchanged from baseline within treatment group, and not different between treatment groups (data not shown).
Our findings suggest that a switch to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir is non-inferior to continuing an existing NNRTI-based regimen for the treatment of virologically suppressed adult patients with HIV and no history of virological failure. To the best of our knowledge, STRATEGY-NNRTI is the first fully powered study to show the efficacy, safety, and tolerability of switching to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir from an NNRTI, emtricitabine, and tenofovir regimen in such patients (panel).
Research in Context
We searched Medline, Embase, Biosis, and Current Contents with the following search terms for randomised controlled, clinical trials of a switch in treatment from a non-nucleoside reverse transcriptase inhibitor to an integrase inhibitor in virologically suppressed patients with HIV : elvitegravir or vitekta, raltegravir or isentress, dolutegravir or tivicay, HIV integrase inhibitor or integrase strand transfer inhibitor, non-nucleoside reverse transcriptase inhibitor, switch, and simplification. We searched for papers written in English and did our last search on April 14, 2014. Excluding reviews, we identified two reports. SWITCH-ER was a 4 week, randomised, double-blinded crossover study assessing the preference of virologically suppressed patients on efavirenz (n=57) for an efavirenz or raltegravir regimen.15 Most patients preferred raltegravir; these patients also had lower anxiety and stress scores after switching. RASTA was a 48 week, randomised, open-label study assessing virologically suppressed patients switching from a non-nucleoside reverse transcriptase inhibitor (NNRTI; n=16), protease inhibitor (n=23), or other antiretroviral (n=2) to raltegravir.16 Virological failure was seen in five (13%) patients who switched to raltegravir. Patients who switched from efavirenz (n=15) had improvement in cognitive function evidenced by statistically significant improvement in delayed recall of words on the Rey's memory test.
STRATEGY-NNRTI is being done in parallel with STRATEGY-PI,17 another fully powered, randomised, open-label non-inferiority trial assessing the safety and efficacy of switching to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir from a ritonavir-boosted protease inhibitor in combination with the same NRTI backbone of emtricitabine and tenofovir in virologically suppressed adult with HIV. In both studies, switching regimen was non-inferior to continuation of the baseline NNRTI or a ritonavir-boosted protease inhibitor regimen in maintaining virological suppression at week 48. The integrase strand transfer inhibitor (INSTI)-based regimen was well-tolerated with favourable patient-reported outcomes. In STRATEGY-NNRTI, rates of virological success for participants switching regimen compared with those continuing an NNRTI plus emtricitabine and tenofovir regimen were high in the overall study population and across subgroups according to age, sex, race, efavirenz versus non-efavirenz NNRTI, and the number of previous regimens. We recorded no treatment-emergent resistance in the switch group up to week 48. The limitations of both studies are similar: both had an open-label study design, which might have contributed to the higher number of discontinuation due to non-virological reasons in the comparator groups. Results of these phase 3b switch trials suggest that coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir is efficacious and well tolerated in virologically suppressed adults with HIV on an NNRTI or a ritonavir-boosted protease inhibitor with emtricitabine and tenofovir regimen considering a regimen modification or simplification.
The low rate of virological failure and absence of emergent resistance in the switch group over 48 weeks suggest that this treatment could be a durable switch option. At baseline, all participants had virological suppression and differed from treatment-naive participants who were viraemic in the pivotal phase 3 studies GS-US-236-01024 and GS-US-236-0103.5 Nevertheless, the absence of emergent resistance to reverse transcriptase and integrase in our trial was reassuring when participants were switched from one antiretroviral drug class to another (ie, NNRTI to INSTI). However, our findings of no emergent resistance might not be replicated in real-life settings in larger groups of patients with less stringent follow-up.
The INSTI regimen was well tolerated by participants who switched from the NNRTI-containing regimen, as evidenced by infrequent discontinuations due to adverse events. Adverse events such as fatigue, cough, headache, and nausea were more common in the switch group but were consistent with the known safety profile of the regimen from previous phase 3 studies.4, 5 After switching treatment, some patients might not tolerate a new regimen, and in this study six patients who switched and one patient who continued the original antiretroviral treatment regimen discontinued study treatment because of adverse events.
Compared with baseline, rates of patient-reported, efavirenz-associated, neuropsychiatric symptoms (eg, anxiety, insomnia, dizziness, and abnormal dreams)3decreased from week 4 through week 48 in participants who switched to the INSTI regimen. The higher rates of neuropsychiatric symptoms shown by the HIV symptom index than reported by investigators suggest that many patients on an efavirenz-containing regimen might continue to have these symptoms for years without reporting them to their physician. Findings from a previous efavirenz-to-rilpivirine open-label switch study and several small double-blind studies assessing a switch from efavirenz to etravirine or raltegravir have also shown similar improvement in neuropsychiatric symptoms.15, 18, 19 Efavirenz is a recommended or first-line NNRTI in most HIV treatment guidelines1, 2, 9 and is the comparator treatment in non-inferiority trials of many new antiretroviral drugs.4 Although the virological efficacy of an efavirenz-containing regimen and the INSTI regimen was similar between our trial and a previous trial of treatment-naive patients,4 the tolerability profile of the INSTI regimen, as defined by investigator-reported adverse events and patient-reported outcomes, differentiates it from efavirenz.
Participants switching treatment had increases in serum creatinine concentrations consistent with the inhibitory effect of cobicistat on the multidrug and toxin extrusion-1 (MATE-1; also known as SLCA7A1) renal transporter, which mediates renal tubular creatinine secretion.20, 21 The scale of increase in serum creatinine concentration seen in this study was similar to that seen in the pivotal phase 3 studies of treatment-naive patients.4, 5 Use of cobicistat in patients with estimated glomerular filtration rates lower than that recruited to this study is under investigation.22 Although the long-term effect of cobicistat inhibition on renal transporters is unknown, studies of cobicistat in healthy volunteers showed that inhibition on MATE-1 is reversible on its discontinuation.20 Switching to the INSTI regimen from a regimen containing efavirenz was associated with a small improvement in some fasting lipid variables, which might not be clinically significant but is consistent with the preferential lipid profile of the INSTI regimen compared with efavirenz, emtricitabine, and tenofovir as seen in a previous study (GS-US-236-0102).4 Fasting lipid parameters such as low-density lipoprotein cholesterol and triglycerides did not worsen with the switch to a cobicistat-boosted regimen, which was reassuring. Cobicistat is a pharmacokinetic booster that has been likened to ritonavir, which is known for its lipid effects.23
Some limitations of this study include the small number of women and the open-label design. The difference in rates of virological success might have been smaller if the study had been double-blinded. The higher rate of virological success in the switch group was driven primarily by the higher rate of discontinuation in the no-switch group for non-virological reasons. Participants with tolerability issues on an NNRTI or those on a multitablet NNRTI-based regimen who were not assigned to the switch group might have felt deprived of the chance to try the switch treatment and might have been more likely to withdraw from the study. Additionally, a potential bias could have occurred in patient-reported symptoms because of knowledge of treatment assignment. Potential bias also exists when patients are excluded from the intention-to-treat analysis population after randomisation. In this study, only participants with a major eligibility violation (eg, prohibited resistance mutations to study drugs) were excluded, and this was done with equal scrutiny without regards for treatment assignment. Investigators might also have been more likely to attribute an adverse event to study drug in patients in the switch group than in those who continued a stable regimen-this might explain the higher rates of some investigator-reported adverse events in participants who switched treatment. These biases are less likely to exist in a double-blind study, but such a study would hamper assessment of patient satisfaction with a single-tablet versus multitablet regimen. Additionally, because we enrolled individuals receiving various NNRTIs, including nevirapine, which is given only as part of a multitablet NNRTI-containing regimen, a double-blinded study with placebo pills would have been impractical. Finally, the well described side-effects of some NNRTIs such as efavirenz and the increases in serum creatinine concentration associated with a cobicistat-containing regimen would make double-blinding less effective.
Few participants were on a multitablet NNRTI-containing regimen at screening. Most of these individuals enrolled in the study because they wanted to simplify their treatment regimen. One possible definition of simplification is the reduction in the number of pills or dosing frequency of antiretroviral treatment. Findings from studies assessing regimen simplification strategies showed that patients prefer to take fewer pills,24, 25 and findings from observational studies indicate that virological and clinical outcomes can be better for patients treated with single-tablet versus multitablet regimen, even in the most difficult-to-treat patient populations.26-29 The benefits of a single-tablet regimen include improved adherence, reduced risk of selective noncompliance, and lower risk of prescription error, all of which might decrease the risk of treatment failure and drug resistance.30
Because continuation of an NNRTI-containing single-tablet or multitablet regimen is not suitable for all patients, coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir-the first INSTI-based single-tablet regimen-is an alternative treatment option for virologically suppressed patients with no history of virological failure or resistance to study drugs.