Switching HIV treatment in adults based on CD4 count versus viral load monitoring: a randomized, non-inferiority trial in Thailand

Virological failure and treatment switch after ART initiation among people living with HIV with and without routine viral load monitoring in Asia

INTRODUCTION

Viral load (VL) testing is still challenging to monitor treatment responses of antiretroviral therapy (ART) for HIV treatment programme in Asia. We assessed the association between routine VL testing and virological failure (VF) and determine factors associated with switching to second-line regimen.

METHODS

Among 21 sites from the TREAT Asia HIV Observational Database (TAHOD), people living with HIV (PLHIV) aged ≥18 years initiating ART from 2003 to 2021 were included. We calculated the average number of VL tests per patient per year between the date of ART initiation and the most recent visit. If the median average number of VL tests was ≥ 0.80 per patient per year, the site was classified as a routine VL site. A site with a median < 0.80 was classified into the non-routine VL sites. VF was defined as VL ≥1000 copies/ml during first-line therapy. Factors associated with VF were analysed using generalized estimating equations with Poisson distribution.

RESULTS

Of 6277 PLHIV starting ART after 2003, 3030 (48%) were from 11 routine VL testing sites and 3247 (52%) were from 10 non-routine VL testing sites. The median follow-up was 9 years (IQR 5-13). The median age was 35 (30-42) years; 68% were male and 5729 (91%) started non-nucleoside reverse-transcriptase inhibitor-based regimen. The median pre-ART CD4 count in PLHIV from routine VL sites was lower compared to non-routine VL sites (144 vs. 156 cells/mm3 , p <0.001). Overall, 1021 subsequent VF at a rate of 2.15 (95% CI 2.02-2.29) per 100 person-years (PY). VF was more frequent at non-routine VL sites (adjusted incidence rate ratio 2.85 [95% CI 2.27-3.59]) compared to routine VL sites. Other factors associated with an increased rate of VF were age <50 years and CD4 count <350 cells/mm3 . A total of 817 (13%) patients switched to second-line regimen at a rate of 1.44 (95% CI 1.35-1.54) per 100 PY. PLHIV at routine VL monitoring sites were at higher risk of switching than those at non-routine VL sites (adjusted sub-hazard ratio 1.78 95% CI [1.17-2.71]).

CONCLUSIONS

PLHIV from non-routine VL sites had a higher incidence of persistent VF and a low switching regimen rate, reflecting possible under-utilized VL testing.

Durability of non-nucleotide reverse transcriptase inhibitor-based first-line ART regimens after 7 years of treatment in rural Uganda: A prospective cohort study

Most antiretroviral therapy (ART) programs in resource-limited settings have historically used non-nucleotide reverse transcriptase inhibitor (NNRTI)-based regimens with limited access to routine viral load (VL) testing. We examined the long-term success of these regimens in rural Uganda among participants with 1 measured suppressed VL.We conducted a prospective cohort study of participants who had been on NNRTI-based first-line regimens for ≥4 years and had a VL <1000 copies/mL at enrollment in Jinja, Uganda. We collected clinical and behavioral data every 6 months and measured VL again after 3 years. We quantified factors associated with virologic failure (VF) (VL ≥ 1000 copies/mL) using Wilcoxon Rank Sum, chi-square, and Fisher's Exact Tests.We enrolled 503 participants; 75.9% were female, the median age was 45 years, and the median duration of time on ART was 6.8 years (IQR = 6.0-7.6 years). Sixty-nine percent of participants were receiving nevirapine, lamivudine, and zidovudine regimens; 22.5% were receiving efavirenz, lamivudine, and zidovudine; and 8.6% were receiving other regimens. Of the 479 with complete follow-up data, 12 (2.5%) had VL ≥ 1000 copies/mL. VF was inversely associated with reporting never missing pills (41.7% of VFs vs 72.8% non-VFs, P = .034). There were differences in distribution of the previous ART regimens (P = .005), but no clear associations with specific regimens. There was no association between having a VL of 50 to 999 copies/mL at enrollment and later VF (P = .160).Incidence of VF among individuals receiving ART for nearly 7 years was very low in the subsequent 3 years. NNRTI-based regimens appear to be very durable among those with good initial adherence.

Adaptive Viral Load Monitoring Frequency to Facilitate Differentiated Care: A Modeling Study From Rakai, Uganda

BACKGROUND

After scale-up of antiretroviral therapy (ART), routine annual viral load monitoring has been adopted by most countries, but reduced frequency of viral load monitoring may offer cost savings in resource-limited settings. We investigated if viral load monitoring frequency could be reduced while maintaining detection of treatment failure.

METHODS

The Rakai Health Sciences Program performed routine, biannual viral load monitoring on 2489 people living with human immunodeficiency virus (age ≥15 years). On the basis of these data, we built a 2-stage simulation model to compare different viral load monitoring schemes. We fit Weibull regression models for time to viral load >1000 copies/mL (treatment failure), and simulated data for 10 000 individuals over 5 years to compare 5 monitoring schemes to the current viral load testing every 6 months and every 12 months.

RESULTS

Among 7 monitoring schemes tested, monitoring every 6 months for all subjects had the fewest months of undetected failure but also had the highest number of viral load tests. Adaptive schemes using previous viral load measurements to inform future monitoring significantly decreased the number of viral load tests without markedly increasing the number of months of undetected failure. The best adaptive monitoring scheme resulted in a 67% reduction in viral load measurements, while increasing the months of undetected failure by <20%.

CONCLUSIONS

Adaptive viral load monitoring based on previous viral load measurements may be optimal for maintaining patient care while reducing costs, allowing more patients to be treated and monitored. Future empirical studies to evaluate differentiated monitoring are warranted.

Handling an uncertain control group event risk in non-inferiority trials: non-inferiority frontiers and the power-stabilising transformation

Background

Non-inferiority trials are increasingly used to evaluate new treatments that are expected to have secondary advantages over standard of care, but similar efficacy on the primary outcome. When designing a non-inferiority trial with a binary primary outcome, the choice of effect measure for the non-inferiority margin (e.g. risk ratio or risk difference) has an important effect on sample size calculations; furthermore, if the control event risk observed is markedly different from that assumed, the trial can quickly lose power or the results become difficult to interpret.

Methods

We propose a new way of designing non-inferiority trials to overcome the issues raised by unexpected control event risks. Our proposal involves using clinical judgement to specify a ‘non-inferiority frontier’, i.e. a curve defining the most appropriate non-inferiority margin for each possible value of control event risk. Existing trials implicitly use frontiers defined by a fixed risk ratio or a fixed risk difference. We discuss their limitations and propose a fixed arcsine difference frontier, using the power-stabilising transformation for binary outcomes, which may better represent clinical judgement. We propose and compare three ways of designing a trial using this frontier: testing and reporting on the arcsine scale; testing on the arcsine scale but reporting on the risk difference or risk ratio scale; and modifying the margin on the risk difference or risk ratio scale after observing the control event risk according to the power-stabilising frontier.

Results

Testing and reporting on the arcsine scale leads to results which are challenging to interpret clinically. For small values of control event risk, testing on the arcsine scale and reporting results on the risk difference scale produces confidence intervals at a higher level than the nominal one or non-inferiority margins that are slightly smaller than those back-calculated from the power-stabilising frontier alone. However, working on the arcsine scale generally requires a larger sample size compared to the risk difference scale. Therefore, working on the risk difference scale, modifying the margin after observing the control event risk, might be preferable, as it requires a smaller sample size. However, this approach tends to slightly inflate type I error rate; a solution is to use a slightly lower significance level for testing, although this modestly reduces power. When working on the risk ratio scale instead, the same approach based on the modification of the margin leads to power levels above the nominal one, maintaining type I error under control.

Conclusions

Our proposed methods of designing non-inferiority trials using power-stabilising non-inferiority frontiers make trial design more resilient to unexpected values of the control event risk, at the only cost of requiring somewhat larger sample sizes when the goal is to report results on the risk difference scale.

Routine versus Targeted Viral Load Strategy among Patients Starting Antiretroviral in Hanoi, Vietnam

INTRODUCTION

HIV viral load (VL) testing is recommended by the WHO as the preferred method for monitoring patients on antiretroviral therapy (ART). However, evidence that routine VL (RVL) monitoring improves clinical outcomes is lacking.

METHODS

We conducted a prospective, randomized controlled trial of RVL monitoring every six months versus a targeted VL (TVL) strategy (routine CD4 plus VL testing if clinical or immunological failure) in patients starting ART between April 2011 and April 2014 at Bach Mai Hospital in Hanoi. Six hundred and forty-seven subjects were randomized to RVL (n = 305) or TVL monitoring (n = 342) and followed up for three years. Primary endpoints were death or WHO clinical Stage 4 events between six and thirty-six months of ART and rate of virological suppression at three years.

RESULTS

Overall, 37.1% of subjects were female, median age was 33.4 years (IQR: 29.5 to 38.6), and 47% had a CD4 count ≤100 cells/mm³ at time of ART initiation. Approximately 44% of study events (death, LTFU, withdrawal, or Stage 4 event) and 68% of deaths occurred within the first six months of ART. Among patients on ART at six months, death or Stage 4 event occurred in 3.6% of RVL and 3.9% of TVL (p = 0.823). Survival analysis showed no significant difference between the groups (p = 0.825). Viral suppression at 36 months of ART was 97.2% in RVL and 98.9% in TVL (p = 0.206) at a threshold of 400 copies/mL and was 98.0% in RVL and 98.9% in TVL (p = 0.488) at 1000 copies/mL. In ITT analysis, 20.7% in RVL and 21.9% in TVL (p = 0.693) were unsuppressed at 1000 copies/mL.

CONCLUSIONS

We found no significant difference in rates of death or Stage 4 events and virological failure in patients with RVL monitoring compared to those monitored with a TVL strategy after three years of follow-up. Viral suppression rates were high overall and there were few study events among patients alive and on ART after six months, limiting the study's power to detect a difference among study arms. Nonetheless, these data suggest that the choice of VL monitoring strategy may have less impact on patient outcomes compared to efforts to reduce early mortality and improve ART retention.

Associations between baseline characteristics, CD4 cell count response and virological failure on first-line efavirenz + tenofovir + emtricitabine for HIV

OBJECTIVES

The aim of this study was to investigate associations between baseline characteristics and CD4 cell count response on first-line antiretroviral therapy and risk of virological failure (VF) with or without drug resistance.

METHODS

We conducted an analysis of UK Collaborative HIV Cohort data linked to the UK HIV Drug Resistance Database. Inclusion criteria were viral sequence showing no resistance prior to initiation of first-line efavirenz + tenofovir disoproxil fumarate + emtricitabine and virological suppression within 6 months. Outcomes of VF (≥200 copies/mL) with or without drug resistance were assessed using a competing risks approach fitted jointly with a model for CD4 cell count recovery. Hazard ratios for each VF outcome were estimated for baseline CD4 cell count and viral load and characteristics of CD4 cell count response using latent variables on a standard normal scale.

RESULTS

A total of 3640 people were included with 338 VF events; corresponding viral sequences were available in 134 with ≥1 resistance mutation in 36. VF with resistance was associated with lower baseline CD4 (0.30, 0.09-0.62), lower CD4 recovery (0.04, 0.00-0.17) and higher CD4 variability (4.40, 1.22-12.68). A different pattern of associations was observed for VF without resistance, but the strength of these results was less consistent across sensitivity analyses. Cumulative incidence of VF with resistance was estimated to be <2% at 3 years for baseline CD4 ≥350 cells/μL.

CONCLUSION

Lower baseline CD4 cell count and suboptimal CD4 recovery are associated with VF with drug resistance. People with low CD4 cell count before ART or with suboptimal CD4 recovery on treatment should be a priority for regimens with high genetic barrier to resistance.

Lack of effectiveness of adherence counselling in reversing virological failure among patients on long-term antiretroviral therapy in rural Uganda

Objectives

The current World Health Organization and Uganda Ministry of Health HIV treatment guidelines recommend that asymptomatic patients who have a viral load (VL) ≥ 1000 HIV‐1 RNA copies/mL should receive adherence counselling and repeat VL testing before switching to second‐line therapy. We evaluated the effectiveness of this strategy in a large HIV treatment programme of The AIDS Support Organisation Jinja in Jinja, Uganda.

Methods

We measured the HIV VL at enrolment, and for participants with VL ≥ 1000 copies/mL we informed them of their result, offered enhanced adherence counselling and repeated the VL measurement after 3 months. All blood samples with VL ≥ 1000 copies/mL were sequenced in the polymerase (pol) region, a 1257‐bp fragment spanning the protease and reverse transcriptase genes.

Results

One thousand and ninety‐one participants were enrolled in the study; 74.7% were female and the median age was 44 years [interquartile range (IQR) 39–50 years]. The median time on antiretroviral therapy (ART) at enrolment was 6.75 years (IQR 5.3–7.6 years) and the median CD4 cell count was 494 cells/μL (IQR 351–691 cells/μL). A total of 113 participants (10.4%) had VLs ≥ 1000 copies/mL and were informed of the VL result and its implications and given adherence counselling. Of these 113 participants, 102 completed 3 months of follow‐up and 93 (91%) still had VLs ≥ 1000 copies/mL. We successfully genotyped HIV for 105 patients (93%) and found that 103 (98%) had at least one mutation: eight (7.6%) had only one mutation, 94 (89.5%) had two mutations and one sample (1%) had three mutations.

Conclusions

In this study, enhanced adherence counselling was not effective in reversing virologically defined treatment failure for patients on long‐term ART who had not previously had a VL test.

Long term renal function in Asian HIV-1 infected adults receiving tenofovir disoproxil fumarate without protease inhibitors

OBJECTIVES

The risk of kidney dysfunction on the WHO recommended first line regimens containing tenofovir disoproxil fumarate (TDF) without protease inhibitors (PI) remains unclear in Asian patients, especially those with low body weight.

METHODS

Using data collected in a multicenter clinical trial in Thailand and proportional hazard regression models, we compared the risk of a >25% estimated glomerular filtration rate (eGFR) reduction in HIV naïve patients initiating TDF or zidovudine (AZT) containing non-PI regimen.

RESULTS

Of 640 patients included in the analysis, 461 (72%) received a TDF-containing regimen for a median 6.7 years and 179 (28%) an AZT-containing regimen for 6.5 years. The risk of a >25% eGFR reduction was not associated with treatment (HR 1.11, 95% CI 0.84-1.47, P = 0.46). In multivariate analysis, the risk of >25% eGFR reduction form baseline was associated with body weight at baseline (HR 2.12, 95% CI 1.48-3.02 for <48 kg patients and HR 1.64, 95% CI 1.20-2.25 for 48-59.9 kg patients, compared to those with >60 kg, P < 0.001) and hypertension (HR 4.03, 95% CI 2.0-8.0, P < 0.001). The effect of baseline weight on >25% eGFR reduction did not significantly vary with treatment (P = 0.27).

CONCLUSIONS

The risk of eGFR reduction was not higher on TDF- versus AZT-based non-PI regimens. Although the risk of eGFR reduction was greater for patients of lower body weight, this risk was not significantly increased by TDF.

Point-of-Care HIV Viral Load Testing: an Essential Tool for a Sustainable Global HIV/AIDS Response

The global public health community has set ambitious treatment targets to end the HIV/AIDS pandemic. With the notable absence of a cure, the goal of HIV treatment is to achieve sustained suppression of an HIV viral load, which allows for immunological recovery and reduces the risk of onward HIV transmission. Monitoring HIV viral load in people living with HIV is therefore central to maintaining effective individual antiretroviral therapy as well as monitoring progress toward achieving population targets for viral suppression. The capacity for laboratory-based HIV viral load testing has increased rapidly in low- and middle-income countries, but implementation of universal viral load monitoring is still hindered by several barriers and delays. New devices for point-of-care HIV viral load testing may be used near patients to improve HIV management by reducing the turnaround time for clinical test results. The implementation of near-patient testing using these new and emerging technologies may be an essential tool for ensuring a sustainable response that will ultimately enable an end to the HIV/AIDS pandemic. In this report, we review the current and emerging technology, the evidence for decentralized viral load monitoring by non-laboratory health care workers, and the additional considerations for expanding point-of-care HIV viral load testing.

Clinical Benefits and Cost-Effectiveness of Laboratory Monitoring Strategies to Guide Antiretroviral Treatment Switching in India

Current Indian guidelines recommend twice-annual CD4 testing to monitor first-line antiretroviral therapy (ART), with a plasma HIV RNA test to confirm failure if CD4 declines, which would prompt a switch to second-line ART. We used a mathematical model to assess the clinical benefits and cost-effectiveness of alternative laboratory monitoring strategies in India. We simulated a cohort of HIV-infected patients initiating first-line ART and compared 11 strategies with combinations of CD4 and HIV RNA testing at varying frequencies. We included adaptive strategies that reduce the frequency of tests after 1 year from 6 to 12 months for virologically suppressed patients. We projected life expectancy, time on failed first-line ART, cumulative 10-year HIV transmissions, lifetime cost (2014 US dollars), and incremental cost-effectiveness ratios (ICERs). We defined strategies as cost-effective if their ICER was <1 × the Indian per capita gross domestic product (GDP, $1,600). We found that the current Indian guidelines resulted in a per person life expectancy (from mean age 37) of 150.2 months and a per person cost of $2,680. Adding annual HIV RNA testing increased survival by ∼8 months; adaptive strategies were less expensive than similar nonadaptive strategies with similar life expectancy. The most effective strategy with an ICER <1 × GDP was the adaptive HIV RNA strategy (ICER $840/year). Cumulative 10-year transmissions decreased from 27.2/1,000 person-years with standard-of-care to 20.9/1,000 person-years with adaptive HIV RNA testing. In India, routine HIV RNA monitoring of patients on first-line ART would increase life expectancy, decrease transmissions, be cost-effective, and should be implemented.

Ten year experience with antiretroviral treatment in Cambodia: Trends in patient characteristics and treatment outcomes

BACKGROUND

Although HIV disease stage at ART initiation critically determines ART outcomes, few reports have longitudinally monitored this within Asia. Using prospectively collected data from a large ART program at Sihanouk Hospital Center of Hope in Cambodia, we report on the change in patient characteristics and outcomes over a ten-year period.

METHODS

We conducted a retrospective analysis including all adults (≥ 18 years old) starting ART from March 2003-March 2013 in a non-governmental hospital in Phnom Penh, Cambodia. The cumulative incidence of death, lost to follow-up (LTFU), attrition (death or LTFU) and first line treatment failure were calculated using Kaplan-Meier methods. Independent risk factors for these outcomes were determined using Cox regression modeling.

RESULTS

Over the ten-year period, 3581 patients initiated ART with a median follow-up time of 4.8 years (IQR 2.8-7.2). The median age was 35 years (IQR 30-41), 54% were female. The median CD4 count at ART initiation increased from 22 cells/μL (IQR 4-129) in 2003 to 218 (IQR 57-302) in 2013. Over the 10 year period, a total of 282 (7.9%) individuals died and 433 (12.1%) were defined LTFU. Program attrition (died or LTFU) was 11.1% (95% CI: 10.1%- 12.4%) at one year, 16.3% (95% CI: 15.1%-17.6%) at three years, 19.8% (95% CI: 18.5%-21.2%) at five years and 23.3% (95% CI: 21.6-25.1) at ten years. Male sex and low baseline body mass index (BMI) were associated with increased attrition. Factors independently associated with mortality included a low baseline CD4 count, older age, male sex, low baseline BMI and hepatitis B co-infection. Individuals aged above 40 years old had an increased risk of mortality but were less likely to LTFU. There were a total of 137 individuals with first line ART failure starting second line treatment. The probability of first line failure was estimated at 2.8% (95% CI: 2.3%-3.4%) at 3 years, 4.6% (95% CI: 3.9%-5.5%) at 5 years and 7.8% (95% CI 4.8%-12.5%) at ten years of ART. The probability was particularly high in the first few program years. A lower risk was observed among individuals starting ART during the 2006-2008 period. Factors independently associated with an increased risk of treatment failure included ART-experience, NVP-based ART and a baseline CD4 count below 200 cells/μL.

CONCLUSIONS

Overall program outcomes were fair, and generally compare well to other reports from the region. Despite gradually earlier initiation of ART over the ten year period, ART is still initiated at too low CD4 count levels, warranting increased efforts for early HIV diagnosis and enrolment/retention into HIV care. Tailored strategies for poor prognostic groups (older age, male, low BMI) should be designed and evaluated.

Feasibility of antiretroviral treatment monitoring in the era of decentralized HIV care: a systematic review

BACKGROUND

Regular monitoring of HIV patients who are receiving antiretroviral therapy (ART) is required to ensure patient benefits and the long-term effectiveness and sustainability of ART programs. Prompted by WHO recommendations for expansion and decentralization of HIV treatment and care in low and middle income countries, we conducted a systematic review to assess the feasibility of treatment monitoring in these settings.

METHODS

A comprehensive search strategy was developed using a combination of MeSH and free text terms relevant to HIV treatment and care, health service delivery, health service accessibility, decentralization and other relevant terms. Five electronic databases and two conference websites were searched to identify relevant studies conducted in LMICs, published in English between Jan 2006 and Dec 2015. Outcomes of interest included the proportion of patients who received treatment monitoring and health system factors related to monitoring of patients on ART under decentralized HIV service delivery models.

RESULTS

From 5363 records retrieved, twenty studies were included in the review; all but one was conducted in sub-Saharan African countries. The majority of studies (15/20) had relatively short follow-up duration (≤24 months), and only two studies were specifically designed to assess treatment monitoring practices. The most frequently studied follow-up period was 12 months and a wide range of treatment monitoring coverage was observed. The reported proportions of patients on ART who received CD4 monitoring ranged from very low (6%; N = 2145) to very high (95%; N = 488). The median uptake of viral load monitoring was 86% with studies in program settings reporting coverage as low as 14%. Overall, the longer the follow-up period, the lower the proportion of patients who received regular monitoring tests; and programs in rural areas reported low coverage of laboratory monitoring. Moreover, uptake in the context of research had significantly better where monitoring was done by dedicated research staff. In the absence of point of care (POC) testing, the limited capacity for blood sample transportation between clinic and laboratory and poor quality of nursing staff were identified as a major barrier for treatment monitoring practice.

CONCLUSIONS

There is a paucity of data on the uptake of treatment monitoring, particularly with longer-term follow-up. Wide variation in access to both virological and immunological regular monitoring was observed, with some clinics in well-resourced settings supported by external donors achieving high coverage. The feasibility of treatment monitoring, particularly in decentralized settings of HIV treatment and care may thus be of concern and requires further study. Significant investment in POC diagnostic technologies and, improving the quality of and training for nursing staff is required to ensure effective scale up of ART programs towards the targets of 90-90-90 by the year 2020.

Predictors of treatment failure on second-line antiretroviral therapy among adults in northwest Ethiopia: a multicentre retrospective follow-up study

BACKGROUND

The number of patients using second-line antiretroviral therapy (ART) has increased over time. In Ethiopia, 1.5% of HIV infected patients on ART are using a second-line regimen and little is known about its effect in this setting.

OBJECTIVE

To estimate the rate and predictors of treatment failure on second-line ART among adults living with HIV in northwest Ethiopia.

SETTING

An institution-based retrospective follow-up study was conducted at three tertiary hospitals in northwest Ethiopia from March to May 2015.

PARTICIPANTS

356 adult patients participated and 198 (55.6%) were males. Individuals who were on second-line ART for at least 6 months of treatment were included and the data were collected by reviewing their records.

PRIMARY OUTCOME MEASURE

The primary outcome was treatment failure defined as immunological failure, clinical failure, death, or lost to follow-up. To assess our outcome, we used the definitions of the WHO 2010 guideline.

RESULT

The mean±SD age of participants at switch was 36±8.9 years. The incidence rate of failure was 61.7/1000 person years. The probability of failure at the end of 12 and 24 months were 5.6% and 13.6%, respectively. Out of 67 total failures, 42 (62.7%) occurred in the first 2 years. The significant predictors of failure were found to be: WHO clinical stage IV at switch (adjusted HR (AHR) 2.1, 95% CI 1.1 to 4.1); CD4 count <100 cells/mm³ at switch (AHR 2.0, 95% CI 1.2 to 3.5); and weight change (AHR 0.92, 95% CI 0.88 to 0.95).

CONCLUSIONS

The rate of treatment failure was highest during the first 2 years of treatment. WHO clinical stage, CD4 count at switch, and change in weight were found to be predictors of treatment failure.

In-depth analysis of HIV-1 drug resistance mutations in HIV-infected individuals failing first-line regimens in West and Central Africa

OBJECTIVE

In resource-limited countries, antiretroviral therapy (ART) has been scaled up, but individual monitoring is still suboptimal. Here, we studied whether or not ART had an impact on the frequency and selection of drug resistance mutations (DRMs) under these settings. We also examined whether differences exist between HIV-1 genetic variants.

DESIGN

A total of 3736 sequences from individuals failing standard first-line ART (n = 1599, zidovudine/stavudine + lamivudine + neviparine/efavirenz) were analyzed and compared with sequences from reverse transcriptase inhibitor (RTI)-naive individuals (n = 2137) from 10 West and Central African countries.

METHODS

Fisher exact tests and corrections for multiple comparisons were used to assess the significance of associations.

RESULTS

All RTI-DRM from the 2015 International Antiviral Society list, except F227C, and nine mutations from other expert lists were observed to confer extensive resistance and cross-resistance. Five additional independently selected mutations (I94L, L109I, V111L, T139R and T165L) were statistically associated with treatment. The proportion of sequences with multiple mutations and the frequency of all thymidine analog mutations, M184V, certain NNRTIS, I94L and L109I showed substantial increase with time on ART. Only one nucleoside and two nonnucleoside RTI-DRMs differed by subtype/circulating recombinant form.

CONCLUSION

This study validates the global robustness of the actual DRM repertoire, in particular for circulating recombinant form 02 predominating in West and Central Africa, despite our finding of five additional selected mutations. However, long-term ART without virological monitoring clearly leads to the accumulation of mutations and the emergence of additional variations, which limit drug options for treatment and can be transmitted. Improved monitoring and optimization of ART are necessary for the long-term effectiveness of ART.

Projecting the epidemiological effect, cost-effectiveness and transmission of HIV drug resistance in Vietnam associated with viral load monitoring strategies

OBJECTIVES

The objective of this study was to investigate the potential epidemiological impact of viral load (VL) monitoring and its cost-effectiveness in Vietnam, where transmitted HIV drug resistance (TDR) prevalence has increased from <5% to 5%-15% in the past decade.

METHODS

Using a population-based mathematical model driven by data from Vietnam, we simulated scenarios of various combinations of VL testing coverage, VL thresholds for second-line ART initiation and availability of HIV drug-resistance tests. We assessed the cost per disability-adjusted life year (DALY) averted for each scenario.

RESULTS

Projecting expected ART scale-up levels, to approximately double the number of people on ART by 2030, will lead to an estimated 18 510 cases (95% CI: 9120-34 600 cases) of TDR and 55 180 cases (95% CI: 40 540-65 900 cases) of acquired drug resistance (ADR) in the absence of VL monitoring. This projection corresponds to a TDR prevalence of 16% (95% CI: 11%-24%) and ADR of 18% (95% CI: 15%-20%). Annual or biennial VL monitoring with 30% coverage is expected to relieve 12%-31% of TDR (2260-5860 cases), 25%-59% of ADR (9620-22 650 cases), 2%-6% of HIV-related deaths (360-880 cases) and 19 270-51 400 DALYs during 2015-30. The 30% coverage of VL monitoring is estimated to cost US$4848-5154 per DALY averted. The projected additional cost for implementing this strategy is US$105-268 million over 2015-30.

CONCLUSIONS

Our study suggests that a programmatically achievable 30% coverage of VL monitoring can have considerable benefits for individuals and leads to population health benefits by reducing the overall national burden of HIV drug resistance. It is marginally cost-effective according to common willingness-to-pay thresholds.

No differences in clinical outcomes with the addition of viral load testing to CD4 cell count monitoring among HIV infected participants receiving ART in rural Uganda: Long-term results from the Home Based AIDS Care Project

BACKGROUND

We compared clinical outcomes among HIV-infected participants receiving ART who were randomized to viral load (VL) and CD4 cell count monitoring in comparison to CD4 cell count monitoring alone in Tororo, Uganda.

METHODS

Beginning in May 2003, participants with CD4 cell counts <250 cells/μL or WHO stage 3 or 4 disease were randomized to clinical monitoring alone, clinical monitoring plus quarterly CD4 cell counts (CD4-only); or clinical monitoring, quarterly CD4 cell counts and quarterly VL testing (CD4-VL). In 2007, individuals in clinical monitoring arm were re-randomized to the other two arms and all participants were followed until March 31, 2009. We used Cox Proportional Hazard models to determine if study arm was independently associated with the development of opportunistic infections (OIs) or death.

RESULTS

We randomized 1211 participants to the three original study arms and 331 surviving participants in the clinical monitoring arm were re-randomized to the CD4-VL and CD4 only arms. At enrolment the median age was 38 years and the median CD4 cell count was 134 cells/μL. Over a median of 5.2 years of follow-up, 37 deaths and 35 new OIs occurred in the VL-CD4 arm patients, 39 deaths and 42 new OIs occurred in CD4-only patients. We did not observe an association between monitoring arm and new OIs or death (AHR =1.19 for CD4-only vs. CD4-VL; 95 % CI 0.82-1.73).

CONCLUSION

We found no differences in clinical outcomes associated with the addition of quarterly VL monitoring to quarterly CD4 cell count monitoring.

Sustainable HIV treatment in Africa through viral-load-informed differentiated care

There are inefficiencies in current approaches to monitoring patients on antiretroviral therapy in sub-Saharan Africa. Patients typically attend clinics every 1 to 3 months for clinical assessment. The clinic costs are comparable with the costs of the drugs themselves and CD4 counts are measured every 6 months, but patients are rarely switched to second-line therapies. To ensure sustainability of treatment programmes, a transition to more cost-effective delivery of antiretroviral therapy is needed. In contrast to the CD4 count, measurement of the level of HIV RNA in plasma (the viral load) provides a direct measure of the current treatment effect. Viral-load-informed differentiated care is a means of tailoring care so that those with suppressed viral load visit the clinic less frequently and attention is focussed on those with unsuppressed viral load to promote adherence and timely switching to a second-line regimen. The most feasible approach to measuring viral load in many countries is to collect dried blood spot samples for testing in regional laboratories; however, there have been concerns over the sensitivity and specificity of this approach to define treatment failure and the delay in returning results to the clinic. We use modelling to synthesize evidence and evaluate the cost-effectiveness of viral-load-informed differentiated care, accounting for limitations of dried blood sample testing. We find that viral-load-informed differentiated care using dried blood sample testing is cost-effective and is a recommended strategy for patient monitoring, although further empirical evidence as the approach is rolled out would be of value. We also explore the potential benefits of point-of-care viral load tests that may become available in the future.

Lack of awareness of treatment failure among HIV-1-infected patients in Guinea-Bissau - a retrospective cohort study

INTRODUCTION

With more people receiving antiretroviral treatment (ART), the need to detect treatment failure and switch to second-line ART has also increased. We assessed CD4 cell counts (as a marker of treatment failure), determined the rate of switching to second-line treatment and evaluated mortality related to treatment failure among HIV-infected patients in Guinea-Bissau.

METHODS

In this retrospective cohort study, adult patients infected with HIV-1 receiving ≥6 months of ART at an HIV clinic in Bissau were included from June 2005 to July 2014 and followed until January 2015. Treatment failure was defined as 1) a fall in CD4 count to baseline (or below) or 2) CD4 levels persistently below 100 cells/µL after ≥6 months of ART. Cox hazard models, with time since six months of ART as the time-varying coefficient, were used to estimate the hazard ratio for death and loss to follow-up.

RESULTS

We assessed 1,591 HIV-1-infected patients for immunological treatment failure. Treatment failure could not be determined in 594 patients (37.3%) because of missing CD4 cell counts. Among the remaining 997 patients, 393 (39.4%) experienced failure. Only 39 patients (9.9%) with failure were switched from first- to second-line ART. The overall switching rate was 3.1 per 100 person-years. Mortality rate was higher in patients with than without treatment failure, with adjusted hazard rate ratios (HRRs) 10.0 (95% CI: 0.9-107.8), 7.6 (95% CI: 1.6-35.5) and 3.1 (95% CI: 1.5-6.3) in the first, second and following years, respectively. During the first year of follow-up, patients experiencing treatment failure had a higher risk of being lost to follow-up than patients not experiencing treatment failure (adjusted HRR 4.4; 95% CI: 1.7-11.8).

CONCLUSIONS

We found a high rate of treatment failure, an alarmingly high number of patients for whom treatment failure could not be assessed, and a low rate of switching to a second-line therapy. These factors could lead to an increased risk of resistance development and excess mortality.

HIV-1 Drug Resistance and Second-Line Treatment in Children Randomized to Switch at Low Versus Higher RNA Thresholds

BACKGROUND

The PENPACT-1 trial compared virologic thresholds to determine when to switch to second-line antiretroviral therapy (ART). Using PENPACT-1 data, we aimed to describe HIV-1 drug resistance accumulation on first-line ART by virologic threshold.

METHODS

PENPACT-1 had a 2 × 2 factorial design, randomizing HIV-infected children to start protease inhibitor (PI) versus nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, and switch at a 1000 copies/mL versus 30,000 copies/mL threshold. Switch criteria were not achieving the threshold by week 24, confirmed rebound above the threshold thereafter, or Center for Disease Control and Prevention stage C event. Resistance tests were performed on samples ≥1000 copies/mL before switch, resuppression, and at 4-years/trial end.

RESULTS

Sixty-seven children started PI-based ART and were randomized to switch at 1000 copies/mL (PI-1000), 64 PIs and 30,000 copies/mL (PI-30,000), 67 NNRTIs and 1000 copies/mL (NNRTI-1000), and 65 NNRTI and 30,000 copies/mL (NNRTI-30,000). Ninety-four (36%) children reached the 1000 copies/mL switch criteria during 5-year follow-up. In 30,000 copies/mL threshold arms, median time from 1000 to 30,000 copies/mL switch criteria was 58 (PI) versus 80 (NNRTI) weeks (P = 0.81). In NNRTI-30,000, more nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations accumulated than other groups. NNRTI mutations were selected before switching at 1000 copies/mL (23% NNRTI-1000, 27% NNRTI-30,000). Sixty-two children started abacavir + lamivudine, 166 lamivudine + zidovudine or stavudine, and 35 other NRTIs. The abacavir + lamivudine group acquired fewest NRTI mutations. Of 60 switched to second-line, 79% PI-1000, 63% PI-30,000, 64% NNRTI-1000, and 100% NNRTI-30,000 were <400 copies/mL 24 weeks later.

CONCLUSIONS

Children on first-line NNRTI-based ART who were randomized to switch at a higher virologic threshold developed the most resistance, yet resuppressed on second-line. An abacavir + lamivudine NRTI combination seemed protective against development of NRTI resistance.

Monitoring and switching of first-line antiretroviral therapy in adult treatment cohorts in sub-Saharan Africa: collaborative analysis

BACKGROUND

HIV-1 viral load testing is recommended to monitor antiretroviral therapy (ART) but is not universally available. The aim of our study was to assess monitoring of first-line ART and switching to second-line ART in sub-Saharan Africa.

METHODS

We did a collaborative analysis of cohort studies from 16 countries in east Africa, southern Africa, and west Africa that participate in the international epidemiological database to evaluate AIDS (IeDEA). We included adults infected with HIV-1 who started combination ART between January, 2004, and January, 2013. We defined switching of ART as a change from a non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based regimen to one including a protease inhibitor, with adjustment of one or more nucleoside reverse-transcriptase inhibitors (NRTIs). Virological and immunological failures were defined according to WHO criteria. We calculated cumulative probabilities of switching and hazard ratios with 95% CIs comparing routine viral load monitoring, targeted viral load monitoring, CD4 monitoring, and clinical monitoring, adjusting for programme and individual characteristics.

FINDINGS

Of 297,825 eligible patients, 10,352 (3%) switched to second-line ART during 782 ,412 person-years of follow-up. Compared with CD4 monitoring, hazard ratios for switching were 3·15 (95% CI 2·92-3·40) for routine viral load monitoring, 1·21 (1·13-1·30) for targeted viral load monitoring, and 0·49 (0·43-0·56) for clinical monitoring. Of 6450 patients with confirmed virological failure, 58·0% (95% CI 56·5-59·6) switched by 2 years, and of 15,892 patients with confirmed immunological failure, 19·3% (18·5-20·0) switched by 2 years. Of 10,352 patients who switched, evidence of treatment failure based on one CD4 count or viral load measurement ranged from 86 (32%) of 268 patients with clinical monitoring to 3754 (84%) of 4452 with targeted viral load monitoring. Median CD4 counts at switching were 215 cells per μL (IQR 117-335) with routine viral load monitoring, but were lower with other types of monitoring (range 114-133 cells per μL).

INTERPRETATION

Overall, few patients switched to second-line ART and switching happened late in the absence of routine viral load monitoring. Switching was more common and happened earlier after initiation of ART with targeted or routine viral load testing.

FUNDING

National Institute of Allergy and Infectious Diseases, Swiss National Science Foundation.

CD4+ gain percentile curves for monitoring response to antiretroviral therapy in HIV-infected adults

OBJECTIVES

We constructed CD4 cell count gain percentile distributions standardized by baseline CD4 cell count and assessed the association between poor CD4 cell count gain and subsequent death and virological failure on antiretroviral therapy (ART).

DESIGN

Secondary analysis of 10 years of clinical data from a cohort of adults initiated on ART at the Themba Lethu clinic in Johannesburg, South Africa.

METHODS

The generalized additive model for location, scale and shape was used to construct percentile curves for CD4 cell count gain standardized by baseline CD4 cell count in the first 28 months of ART. Cox proportional models were used to assess the association between lower percentiles (<50th) of CD4 cell count gain, and subsequent death and virological failure.

RESULTS

Among 9640 nonpregnant adults 7406, with available CD4 cell count results for CD4 gain calculation at 4 months of ART, 843 (8.7%) died subsequently and 1101 (11.4%) experienced virologic failure, respectively. For CD4 gains below the third percentile, the adjusted hazard ratios at different time points ranged between 2.72 and 5.73 for death, and between 1.48 and 6.93 for virologic failure. The CD4 percentile curves revealed a gradient of increasing risk of subsequent death and virological failure, with lower CD4 gain percentiles and increasing time on ART, and were more informative than the WHO criteria for immunological failure or current CD4 cell count.

CONCLUSION

Percentile curves of CD4 cell count gain provide a simple tool for healthcare workers in low-resource settings to monitor response to ART with improved information regarding risk of death and virological failure compared to current WHO criteria for immunological failure.

Durable Suppression of HIV-1 after Virologic Monitoring-Based Antiretroviral Adherence Counseling in Rakai, Uganda

OBJECTIVES

HIV viral load is recommended for monitoring antiretroviral treatment and identifying treatment failure. We assessed the durability of viral suppression after viral load-triggered adherence counseling among patients with HIV viremia 6 months after ART initiation.

DESIGN

Observational cohort enrolled in an antiretroviral treatment program in rural Uganda.

METHODS

Participants who underwent routine viral load determination every 24 weeks and had at least 48 weeks of follow-up were included in this analysis. Patients with viral loads >400 copies/ml at 24 weeks of treatment were given additional adherence counseling, and all patients were followed to assess the duration of viral suppression and development of virologic failure.

RESULTS

1,841 participants initiating antiretroviral therapy were enrolled in the Rakai Health Sciences Program between June 2005 and June 2011 and were followed with viral load monitoring every 24 weeks. 148 (8%) of patients did not achieve viral suppression at 24 weeks and were given additional adherence counseling. 85 (60%) of these patients had undetectable viral loads at 48 weeks, with a median duration of viral suppression of 240 weeks (IQR 193-288 weeks). Failure to achieve an undetectable viral load at 48 weeks was associated with age <30 years and 24 week viral load >2,000 copies/ml in multivariate logistic regression analysis.

CONCLUSIONS

The majority of patients with persistent viremia who were provided adherence counseling achieved robust viral suppression for a median 4.6 years. Access to virologic monitoring and adherence counseling is a priority in resource-limited settings.

Durability of antiretroviral therapy and predictors of virologic failure among perinatally HIV-infected children in Tanzania: a four-year follow-up

BACKGROUND

In Tanzania, HIV-1 RNA testing is rarely available and not standard of care. Determining virologic failure is challenging and resistance mutations accumulate, thereby compromising second-line therapy. We evaluated durability of antiretroviral therapy (ART) and predictors of virologic failure among a pediatric cohort at four-year follow-up.

METHODS

This was a prospective cross-sectional study with retrospective chart review evaluating a perinatally HIV-infected Tanzanian cohort enrolled in 2008-09 with repeat HIV-1 RNA in 2012-13. Demographic, clinical, and laboratory data were extracted from charts, resistance mutations from 2008-9 were analyzed, and prospective HIV RNA was obtained.

RESULTS

161 (78%) participants of the original cohort consented to repeat HIV RNA. The average age was 12.2 years (55% adolescents ≥12 years). Average time on ART was 6.4 years with 41% receiving second-line (protease inhibitor based) therapy. Among those originally suppressed on a first-line (non-nucleoside reverse transcriptase based regimen) 76% remained suppressed. Of those originally failing first-line, 88% were switched to second-line and 72% have suppressed virus. Increased level of viremia and duration of ART trended with an increased number of thymidine analogue mutations (TAMs). Increased TAMs increased the odds of virologic failure (p = 0.18), as did adolescent age (p < 0.01).

CONCLUSIONS

After viral load testing in 2008-09 many participants switched to second-line therapy. The majority achieved virologic suppression despite multiple resistance mutations. Though virologic testing would likely hasten the switch to second-line among those failing, methods to improve adherence is critical to maximize durability of ART and improve virologic outcomes among youth in resource-limited settings.

Viral load versus CD4⁺ monitoring and 5-year outcomes of antiretroviral therapy in HIV-positive children in Southern Africa: a cohort-based modelling study

OBJECTIVES

Many paediatric antiretroviral therapy (ART) programmes in Southern Africa rely on CD4⁺ to monitor ART. We assessed the benefit of replacing CD4⁺ by viral load monitoring.

DESIGN

A mathematical modelling study.

METHODS

A simulation model of HIV progression over 5 years in children on ART, parameterized by data from seven South African cohorts. We simulated treatment programmes with 6-monthly CD4⁺ or 6- or 12-monthly viral load monitoring. We compared mortality, second-line ART use, immunological failure and time spent on failing ART. In further analyses, we varied the rate of virological failure, and assumed that the rate is higher with CD4⁺ than with viral load monitoring.

RESULTS

About 7% of children were predicted to die within 5 years, independent of the monitoring strategy. Compared with CD4⁺ monitoring, 12-monthly viral load monitoring reduced the 5-year risk of immunological failure from 1.6 to 1.0% and the mean time spent on failing ART from 6.6 to 3.6 months; 1% of children with CD4⁺ compared with 12% with viral load monitoring switched to second-line ART. Differences became larger when assuming higher rates of virological failure. When assuming higher virological failure rates with CD4⁺ than with viral load monitoring, up to 4.2% of children with CD4⁺ compared with 1.5% with viral load monitoring experienced immunological failure; the mean time spent on failing ART was 27.3 months with CD4⁺ monitoring and 6.0 months with viral load monitoring. Conclusion: Viral load monitoring did not affect 5-year mortality, but reduced time on failing ART, improved immunological response and increased switching to second-line ART.

Cost-effectiveness of HIV drug resistance testing to inform switching to second line antiretroviral therapy in low income settings

Background

To guide future need for cheap resistance tests for use in low income settings, we assessed cost-effectiveness of drug resistance testing as part of monitoring of people on first line ART - with switching from first to second line ART being conditional on NNRTI drug resistance mutations being identified.

Methods

An individual level simulation model of HIV transmission, progression and the effect of ART which accounts for adherence and resistance development was used to compare outcomes of various potential monitoring strategies in a typical low income setting in sub-Saharan Africa. Underlying monitoring strategies considered were based on clinical disease, CD4 count or viral load. Within each we considered a strategy in which no further measures are performed, one with a viral load measure to confirm failure, and one with both a viral load measure and a resistance test. Predicted outcomes were assessed over 2015–2025 in terms of viral suppression, first line failure, switching to second line regimen, death, HIV incidence, disability-adjusted-life-years averted and costs. Potential future low costs of resistance tests ($30) were used.

Results

The most effective strategy, in terms of DALYs averted, was one using viral load monitoring without confirmation. The incremental cost-effectiveness ratio for this strategy was $2113 (the same as that for viral load monitoring with confirmation). ART monitoring strategies which involved resistance testing did not emerge as being more effective or cost effective than strategies not using it. The slightly reduced ART costs resulting from use of resistance testing, due to less use of second line regimens, was of similar magnitude to the costs of resistance tests.

Conclusion

Use of resistance testing at the time of first line failure as part of the decision whether to switch to second line therapy was not cost-effective, even though the test was assumed to be very inexpensive.

Delayed switch of antiretroviral therapy after virologic failure associated with elevated mortality among HIV-infected adults in Africa

OBJECTIVE

Routine monitoring of plasma HIV RNA among HIV-infected patients on antiretroviral therapy (ART) is unavailable in many resource-limited settings. Alternative monitoring approaches correlate poorly with virologic failure and can substantially delay switch to second-line therapy. We evaluated the impact of delayed switch on mortality among patients with virologic failure in Africa.

DESIGN

A cohort.

METHODS

We examined patients with confirmed virologic failure on first-line nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens from four cohorts with serial HIV RNA monitoring in Uganda and South Africa. Marginal structural models aimed to estimate the effect of delayed switch on mortality in a hypothetical trial in which switch time was randomly assigned. Inverse probability weights adjusted for measured confounders including time-updated CD4+ T-cell count and HIV RNA. Results: Among 823 patients with confirmed virologic failure, the cumulative incidence of switch 180 days after failure was 30% [95% confidence interval (CI) 27-33]. The majority of patients (74%) had not failed immunologically as defined by WHO criteria by the time of virologic failure. Adjusted mortality was higher for individuals who remained on first-line therapy than for those who had switched [odds ratio (OR) 2.1, 95% CI 1.1-4.2]. Among those without immunologic failure, the relative harm of failure to switch was similar (OR 2.4; 95% CI 0.99-5.8) to that of the entire cohort, although of borderline statistical significance.

CONCLUSION

Among HIV-infected patients with confirmed virologic failure on first-line ART, remaining on first-line therapy led to an increase in mortality relative to switching. Our results suggest that detection and response to confirmed virologic failure could decrease mortality.

Predicting treatment failure in adults and children on antiretroviral therapy: a systematic review of the performance characteristics of the 2010 WHO immunologic and clinical criteria for virologic failure

OBJECTIVE

We systematically reviewed the performance of 2010 WHO immunologic and clinical criteria for predicting virologic failure in HIV-infected patients on antiretroviral therapy (ART).

DESIGN

Systematic review.

METHODS

We used Cochrane Collaboration methods. We calculated unweighted sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of immunologic and clinical criteria for predicting virologic failure.

RESULTS

We identified 18 studies. Sixteen assessed immunologic criteria in adults; 12 defined virologic failure as a plasma viral load of more than 50 to more than 1000 copies/ml in adults, three as viral load at least 5000 copies/ml, and two as viral load more than 10,000 copies/ml; the sensitivity ranged from 16.8 to 54.9%, specificity from 82.9 to 95.5%, PPV from 15.0 to 38.8%, and NPV from 90.9 to 98.6%. Seven studies assessed clinical criteria to predict viral load of more than 50 to more than 1000 copies/ml; the sensitivity was 11.0%, specificity 90.5%, PPV 44.9%, and NPV 90.2%. Seven studies assessed clinical or immunologic criteria defining virologic failure as viral load of more than 50 to more than 1000 copies/ml; their sensitivity was 26.6%, specificity 85.9%, PPV 49.4%, and NPV 91.1%. Four studies assessed immunologic criteria in children; three defined virologic failure as viral load at least 5000 copies/ml and one as viral load at least 400 copies/ml. The sensitivity ranged from 4.5 to 6.3%, specificity from 97.7 to 99.3%, PPV from 20.0 to 54.9%, and NPV from 85.5 to 91.8%.

CONCLUSION

The 2010 WHO clinical and immunologic criteria are insensitive and have low PPV for predicting virologic failure. These data support the strong recommendation 2013 treatment guidelines that viral load testing be used to monitor for, diagnose, and confirm ART failure.