Keywords
HIV/TB coinfection, NNRTI concentrations, drug–drug interactions, antiretroviral therapy, resistance, virological escape
This article is included in the Médecins Sans Frontières gateway.
HIV/TB coinfection, NNRTI concentrations, drug–drug interactions, antiretroviral therapy, resistance, virological escape
Antiretroviral therapy (ART) aims to sustain virological suppression, which is associated with a clinical benefit and immune recovery. It also prevents HIV transmission and limits the emergence of antiretroviral (ARV) drug resistance. In a recent meta-analysis, Gupta et al. reported that East Africa had the highest estimated rate of drug-resistance mutations (29% per year) since the roll-out of ART, with an estimated prevalence of ARV drug resistance of 7.4% at 8 years after rollout1.
In 2016, 80% of the worldwide prescription of ART-included efavirenz (EFV), a non-nucleoside reverse-transcriptase inhibitor (NNRTI)-class drug2. Efavirenz-based ART is also recommended in the context of tuberculosis (TB) coinfection, as drug-drug interactions with rifampicin, a cornerstone anti-TB drug, are limited. However, the risk of central nervous toxicity with EFV may lead to altered adherence to ARTs. Thus, it is important to identify early markers predicting the emergence of new resistance mutations in patients on NNRTI-based ART.
The phase 3 CARINEMO randomized clinical trial enrolled 570 HIV-TB coinfected patients in Mozambique, Africa, and compared the efficacy and safety of two NNRTIs (nevirapine [NVP] and EFV) for ART-naïve patients3. In the intent-to-treat population, 64.6% (95% confidence interval (CI): 58.7-70.1%) of patients who received NVP achieved virological suppression at week 48 (defined as HIV-1 RNA <50 copies per ml), compared with 69.8% (95% CI: 64.1-75.1%) of those who received EFV. The evolution of plasma concentrations of NVP and EFV during and after anti-TB therapy, as well as its association with toxicity and virological suppression, has been previously described4. The emergence of ARV-resistance mutations was observed during the trial and briefly described, but the relationship between NNRTI plasma concentrations and the emergence of resistance was not investigated. Here, we analyzed subgroup datasets from the CARINEMO trial, which provided a unique opportunity to explore the factors associated with viral replication and the emergence of resistance mutations while on ART. These data also offered the possibility to assess the relationship between viral replication, ARV plasma concentrations and the emergence of resistance mutations. The identification of risk factors of virological escape at week 48 in a well-characterized and homogeneous population is critical to prevent treatment failure in settings where the best timing for routine HIV-RNA still needs to be assessed.
The CARINEMO trial (ClinicalTrials.gov identifier: NCT00495326) was conducted in three health centers located in Maputo, Mozambique, from 2007 to 2011; a full description of the trial is available from Bonnet et al.3. Participants were randomized to NVP or EFV (without lead-in dose) and received either a fixed-dose combination of NVP (400 mg/day), lamivudine and stavudine (Triomune®) or EFV (600 mg/day) plus lamivudine and stavudine started 4 weeks after anti-TB treatment initiation and for a duration of 48 weeks. In August 2010, stavudine was replaced by zidovudine. For TB, all patients received a fixed-dose combination of isoniazid (H), rifampicin (R), ethambutol (E) and pyrazinamide (Z) for 2 months, followed by 4 months of isoniazid/rifampin.
Four ethics committees approved the study protocol: the Comite Nacional de Bio-Etica para a Saude (Maputo, Mozambique), the Medecins Sans Frontieres Ethics Review Board (Zurich, Switzerland), the Comite de Protection des Personnes (Saint Germain-en-Laye, France), and the Columbia University ethics review committee (New York, NY, USA). All participants provided signed informed consent.
Plasma HIV-RNA levels were measured at inclusion and then at weeks 12, 24, 36 and 48 using the Roche Cobas Amplicor HIV-1 Monitor Test v1.5 (Roche Diagnostics, Basel, Switzerland) at the molecular biology laboratory of the Instituto Nacional de Saúde, Maputo, Mozambique. Resistance mutations to NRTI and NNRTI were determined in all patients with plasma HIV-1 RNA >400 copies/ml at week 48 by sequencing the reverse transcriptase gene using the consensus technique of the AC11 ANRS Resistance Group (www.hivfrenchresistance.org) at the Department of Virology, Necker Hospital (Paris, France). A patient was defined as having an emergence of resistance mutations at week 48 if at least one (N)NRTI resistance mutation was detected at any level.
Adherence counseling on both ART and anti-TB therapies was provided by the study team at the clinics. At each follow-up visit, adherence to both ART and anti-TB treatment was monitored using an analog visual scale, standardized questionnaire administered by a nurse and pill counts. Adherence to ART was calculated for each time point using pills counts only. The number of returned doses during the last 3 months prior to weeks 12, 24, 36 and 48 were compared to the number of doses prescribed and refills. An indicator of compliance was defined by classifying adherence with a threshold of 95%.
Pre-dose concentrations of NVP and 12 h after the evening intake of EFV were measured at weeks 12, 24, 36 and 48. Patients for whom the measured concentrations were below the limit of quantification at each measurement were removed from the analysis, assuming the ART was not taken at all.
Virological suppression was defined as an HIV-RNA below 400 copies/ml at week 48 and virological escape as an HIV-RNA above 400 copies/ml. Patients switched during follow-up to another ART regimen were excluded from the analysis. Percentiles (P) of drug concentrations were provided for each NNRTI at each time point. The P10, P25, P50, P75 and P95 were calculated and used to categorize drug concentrations. The P10 value was used to classify patients as having low drug concentrations (threshold below which 10% of drug concentrations were measured). Mean changes in HIV-1 RNA values after log transformation at each time point vs. baseline values were compared between patients with and without the emergence of resistance mutations by performing an analysis of covariance at each time point with HIV-1 RNA baseline values (log transformed) and treatment as covariates. Univariate and multivariate logistic regression models were fitted to assess the associations between virological escape and the emergence of resistance mutations at week 48 with drug concentrations at weeks 12 and 24, adherence to ART and other patient-associated factors, such as body mass index, sex, age, CD4 cell counts, as well as the HIV-1 RNA and ART regimen at treatment initiation. For both outcomes, factors associated with a P-value <0.20 in univariate analysis were selected for the initial multivariate analysis and a manual backward stepwise approach was used to obtain the final multivariate model. Only factors significantly associated (P<0.05) with the outcomes remained in the model and the importance of each in the final model was tested with a likelihood ratio test at the same level of significance (5%). The area under the receiver operating characteristics (ROC) curve was computed to assess the prediction of the low drug concentration on the risk of virological escape and the emergence of resistance mutation. The same analysis was repeated to evaluate the prediction of the HIV 1 RNA at weeks 12 and 24 on the risk of virological escape at week 48 and the emergence of resistance mutation. Other statistical comparisons were performed using the Chi-square test, Fisher’s exact test or Student’s t-test as appropriate. A P-value of ≤0.05 was considered statistically significant. Tests were performed with Stata 14 (StataCorp LP, College Station, TX).
Of the 570 patients randomized in the CARINEMO trial, 470 had available measurement of HIV-RNA at week 48. Among these, 446 had at least one measure of detectable drug plasma concentrations without being switched during follow-up to another ART regimen (Figure 1). Demographic data and clinical characteristics at baseline and during the 48-week follow-up are summarized in Table 1. De-identified raw data for each patient is available on figshare5.
Among the 446 patients an adherence rate less than 95% was observed among 7 (1.6%) patients from enrolment up to week 12, in 11 (2.5%) patients from weeks 12 up to 24, in 11 (2.5%) patients between weeks 24 and 36, and 8 (1.8%) patients between weeks 36 and 48.
Among the 446 patients, 54 (12.1%) presented a virological escape; 48 patients (10.8%) had a genotype performed and 35 (7.8%) had at least one major resistance mutation detected on the reverse transcriptase gene. The decrease in HIV-1 RNA levels from baseline was significantly slower in patients in whom resistance mutations were identified at week 48 compared with those with no occurrence of resistance (Table 3).
Percentile values for NVP and EFV drug concentrations at each time points are presented in Table 2. Values of P10, P25 and P50 at week 12 were 1253 ng/ml, 1784 ng/ml and 2786 ng/ml, respectively, for EFV, and 1893 ng/ml, 2996 ng/ml and 4095 ng/ml, respectively, for NVP. The distribution of drug concentrations using these percentile categories differed statistically between patients with virological suppression and those with virological escape at week 48. At week 12, 28.2% (11/39) of patients with a plasma concentration of the NNRTI-component within the P10 failed to suppress their viral load at week 48 compared with 10.1% (35/348) in those with higher concentrations (p=0.001) similar to week 24 (35% [14/40] vs. 9.2% [32/348], respectively; p<0.001). Among these patients, median concentrations were lower in those with virological escape compared to cases with virological suppression at week 12 for the NVP group and in both the EFV and NVP groups at week 24 (Figure 2, p=NS). The same differences were observed in the distribution of drug concentrations between patients with or without the emergence of resistance mutations. At week 12, 21.2% (8/37) of patients presenting plasma drug concentrations of the NNRTI component within the P10 had resistance mutations at week 48, compared with 5.8% (20/344) in those with higher concentrations (p<0.001), similar to week 24 (26.3% [10/38] vs. 5.2% [18/345], respectively).
Data given as mean (standard deviation).
Multivariate analyses showed that plasma drug concentrations below the P10 threshold at weeks 12 and 24 were independently associated with virological escape at week 48 (adjusted odds ratio [aOR]=2.9; 95% CI: 1.1 -7.2; p=0.0312 and aOR=4.2; 95% CI: 1.8-9.8; p=0.0019, respectively), as well as adherence below 95% at week 24 (aOR=10.5; 95% CI: 1.2-89.8; p=0.044, respectively) (Table 4). There was no influence of the choice of the NNRTI component or the CD4 cell count at baseline on factors associated with virological escape at week 48. Drug concentrations below the P10 threshold at weeks 12 and 24 (aOR=4.5; 95% CI: 1.8-14.6; p=0.009 at week 12; aOR=5.1; 95% CI: 1.8-14.6 at week 24) were also independently associated with an increased risk of emergence of resistance mutation as well as the ARV treatment received at initiation (aOR=3.2; 95% CI: 1.1-9.1; p=0.0244), for NVP vs. EFV. Adherence below 95% at week 24 was no longer shown to be associated at the significance level of 5% (p=0.0581) (Table 5).
Among the 345 patients with both mid-dose concentrations at weeks 12 and 24, the ROC analysis showed an area under the curve (AUC) at week 12 of 0.62 (95% CI: 0.52-0.72) and 0.67 (95% CI: 0.65-0.82) at week 24 for virological escape. An AUC of 0.76 (95% CI: 0.66 -0.87) and 0.75 (95% CI: 0.63-0.86) at weeks 12 and 24, respectively, was observed for the emergence of resistance mutations, thus indicating a better predictability of the mid-dose concentration on resistance mutations in contrast to virological escape. When using the HIV-1 RNA values at weeks 12 and 24 to predict the two outcomes, the ROC analysis showed AUCs of 0.69 (95% CI: 0.60-0.77) and 0.66 (95% CI: 0.55-0.76), respectively, for virological escape and 0.72 (95% CI: 0.63-0.80) and 0.75 (95% CI: 0.65-0.86), respectively, for the emergence of resistance mutations. These results indicate a better predictability of the HIV-1 RNA values on resistance mutations in contrast to virological escape.
In the present study, we used the data of a large randomized clinical trial assessing two drugs of the NNRTI class in combination with anti-TB drugs. Our findings showed that very low drug plasma concentrations early after treatment initiation (week 12) were predictive factors of virological escape and the emergence of resistance mutations at week 48. Low drug concentrations may be explained by a suboptimal adherence or a potent drug interaction when patients receive other drugs such as rifampicin. Recently, it was suggested that the wave of ART treatment failure primarily affecting resource-limited countries should be considered as a fourth epidemic6. This epidemic, accompanied by the emergence of ARV drug resistance, could affect 3 to 5 million individuals between 2020 and 20307. Therefore, early predictors of ART failure are critically important. Until low-cost, simple assays for drug monitoring are available, pharmacological drug monitoring cannot be routinely recommended in low-resource settings to trigger drug resistance testing8,9. For this reason, we advocate for the development of easy-to-use point-of-care tests for anti-HIV drugs to help monitoring for adequate drug intake and therefore drug exposure during clinic visits. This would allow reducing unnecessary viral load measurements and viral genotype determination and could prevent unnecessary switches to costly and complex salvage ART in contexts where the preservation of future treatment lines is critical.
Adherence is a complex non-steady phenomenon and there is no gold standard or universal tool at present to detect irregular adherence10–14. This is particularly true during the first months of treatment initiation in a given population for a given ART treatment, taking into account forgiveness of the combined three ARV drugs15. Our study confirms that an adherence rate below 95% is independently associated with an increased risk of virological escape and the emergence of drug resistance16. In the absence of an adequate tool, surveillance of plasma concentrations with a simple assay in a subset of randomly selected patients could be a strategy to monitor a given cohort of patients starting ART. Viral load testing and adequate adherence support from the very first weeks of treatment should also be implemented in these settings17. The World Health Organization recommends performing the first viral load testing after ARV initiation at 24 weeks. However, some field reports have observed an improvement in long-term virological suppression in patients undergoing 12-week viral load testing18. Newly-developed, point-of-care test assays will benefit low-resource settings and help to expand such viral load measurements monitoring17,19,20.
Our results demonstrated that the early detection of low drug plasma levels of the NNRTI component of the treatment regimen was able to discriminate patients who will later develop a resistance mutation. We showed that low to very low drug concentrations (below P10) in the first months after starting ART were significantly associated with the emergence of later virological escape and drug-resistance mutations. We were surprised by the EFV concentration levels in our study, which triggered a signal for viral escape. Indeed, the P10 at week 12 was 1253 ng/ml for the EFV component, whereas concentrations below 1000 ng/ml were sufficient in earlier studies21 to predict treatment failure. Furthermore, the ENCORE1 study showed the efficacy of the 400 mg EFV daily dose, suggesting also that the efficacy cut-off might be lower than 1000 ng/ml22. We hypothesized that the high frequency of CYP2B6 genetic polymorphism in individuals of African descent may explain a population concentration distribution above that observed in Caucasian patients by Marzolini et al.21.
This study has some limitations. First, in the CARINEMO clinical trial, data were collected at fixed time points and HIV-1 RNA and plasma drug concentrations started to be measured for all patients at week 12. This limited the assessment of earlier effects on virological escape and the emergence of resistance mutations in the very first weeks of treatment initiation. Second, included patients may not be representative of larger coinfected TB/HIV populations. In particular, these patients were closely followed and received support to sustain adherence to the ART and TB drugs. However, the use of pill counts only to calculate the compliance rate may have overestimated adherence. This was shown earlier in other reports16,23 as observed by the proportion of patients with adherence below 95% and low drug concentrations, even though other factors such as drug genetic polymorphism may have influenced the drug concentrations. Third, the nucleoside analog (NRTI) backbone used in this study is no longer recommended (d4T/lamivudine or zidovudine/lamivudine) and the current use of a backbone such as tenofovir disoproxil fumarate or tenofovir alafenamide, with a longer intracellular half-life, may have changed these results. Although NVP is no longer a preferred first-line therapy and many countries have now transitioned to a dolutegravir-based regimen, we believe that our results remain relevant. Dolutegravir has a shorter half-life than NVP and EFV, and assessing early drug exposure is likely to be extremely critical. In addition, when combined with anti-TB drugs, the dose of dolutegravir needs to be doubled, which supports the use of EFV-based ARV in coinfected TB patients. Fourth, the co-administration of anti-TB drugs with ART may have altered drug concentrations24 as rifampicin is a known potent inducer of NNRTI metabolism, in particular for NVP-based ART25. However, although no treatment effect was shown in our findings on virological escape, we observed a significant treatment effect in the multivariate analyses on resistance mutations, similar to previous trials26. ARV concentrations measured 12 h post-dose were previously used to predict virological and resistance outcomes, and were significantly associated with both outcomes at week 4814,27,28, despite the high inter-individual variability. Finally, the analyses were performed post hoc and were not discussed at the time of the initial statistical analysis plan.
In summary, early monitoring of drug intake may prevent the occurrence of late virological escape and the selection of viral resistance mutations. Adherence measurement using solely pill counts does not allow for such a prediction. Indeed, higher concentrations of NNRTI were associated with better virological outcomes. In low-resource settings, implementing routine 12-week HIV-1 viral load and innovative adherence measurements might ensure long-term treatment success and reduce the possibility of the emergence of drug resistance mutations.
Raw data associated with this study, including basic demographic information and data on viral load, are available on figshare. DOI: https://doi.org/10.6084/m9.figshare.7655630.v15.
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).
This work was supported by UNITAID.
The funders had no role in experimental design, data analysis and interpretation, or the decision to submit the work for publication.
We thank the medical, research team and patients from the trial sites: Centro de Saúde de Alto Maé, Hospital Geral de Mavalane, Hospital Geral de José Macamo in Maputo, Mozambique; the Instituto Nacional de Saúde; Médecins sans Frontières – Switzerland (MSF- CH), Mozambique; the International Care AIDS Program (ICAP) in Maputo and the Agence nationale de recherches sur le sida et les hépatites virales (ANRS) (for the funding of the trial).
Ilesh V. Jani MD PhD, Nádia Sitoe Bsc, Adolfo Vubil Bsc MSc, Maria Nhadzombo, Fernando Sitoe, Delário Nhumaio, Odete Bule (Instituto Nacional de Saúde, Mozambique); Rui Bastos MD and Elizabete Nunes MD (Hospital Central, Maputo, Mozambique); Paula Samo Gudo MD MPH (National Tuberculosis Control Program, Mozambique); Josué Lima MD and Mie Okamura (International Center for AIDS Care and Treatment Programs, Mozambique); Laura Ciaffi MD, Agnès Sobry MD, Mariano Lugli and Bruno Lab (Médecins Sans Frontières - Switzerland, Mozambique); Avertino Barreto MD (Mozambique National AIDS Service Organisation, Mozambique); Christophe Michon MD (Regional Hospital, Annecy, France); Alexandra Calmy MD PhD (Médecins Sans Frontières; Division of Infectious Diseases, Geneva University Hospital, Geneva, Switzerland); Alpha Diallo (ANRS pharmacovigilance unit, France); Christine Rouzioux PharmD PhD (Paris-Descartes University, EA3620, Sorbonne Paris Cite, APHP, Necker Hospital, Paris, France).
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Is the work clearly and accurately presented and does it cite the current literature?
Yes
Is the study design appropriate and is the work technically sound?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
Partly
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Are the conclusions drawn adequately supported by the results?
Yes
References
1. Paterson DL, Swindells S, Mohr J, Brester M, et al.: Adherence to Protease Inhibitor Therapy and Outcomes in Patients with HIV Infection. Annals of Internal Medicine. 2000; 133 (1). Publisher Full TextCompeting Interests: No competing interests were disclosed.
Reviewer Expertise: I have had experience researching ARV drug concentrations as objective adherence measures & other adherence measures
Is the work clearly and accurately presented and does it cite the current literature?
Yes
Is the study design appropriate and is the work technically sound?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
Yes
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Are the conclusions drawn adequately supported by the results?
Yes
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: HIV and co-infections: Cryptococol Meningitis and Tuberculosis
Alongside their report, reviewers assign a status to the article:
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Version 1 08 Feb 19 |
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