Nevirapine Levels after Discontinuation of Rifampicin Therapy and 60‐Week Efficacy of Nevirapine‐Based Antiretroviral Therapy in HIV‐Infected Patients with Tuberculosis

Evidence for Implementation: Management of TB in HIV and Pregnancy

PURPOSE OF REVIEW

Pregnant people living with HIV (PLWH) are at especially high risk for progression from latent tuberculosis infection (LTBI) to active tuberculosis (TB) disease. Among pregnant PLWH, concurrent TB increases the risk of complications such as preeclampsia, intrauterine fetal-growth restriction, low birth weight, preterm-delivery, perinatal transmission of HIV, and admission to the neonatal intensive care unit. The grave impact of superimposed TB disease on maternal morbidity and mortality among PLWH necessitates clear guidelines for concomitant therapy and an understanding of the pharmacokinetics (PK) and potential drug-drug interactions (DDIs) between antitubercular (anti-TB) agents and antiretroviral therapy (ART) in pregnancy.

RECENT FINDINGS

This review discusses the currently available evidence on the use of anti-TB agents in pregnant PLWH on ART. Pharmacokinetic and safety studies of anti-TB agents during pregnancy and postpartum are limited, and available data on second-line and newer anti-TB agents used in pregnancy suggest that several research gaps exist. DDIs between ART and anti-TB agents can decrease plasma concentration of ART, with the potential for perinatal transmission of HIV. Current recommendations for the treatment of LTBI, drug-susceptible TB, and multidrug-resistant TB (MDR-TB) are derived from observational studies and case reports in pregnant PLWH. While the use of isoniazid, rifamycins, and ethambutol in pregnancy and their DDIs with various ARTs are well-characterized, there is limited data on the use of pyrazinamide and several new and second-line antitubercular drugs in pregnant PLWH. Further research into treatment outcomes, PK, and safety data for anti-TB agent use during pregnancy and postpartum is urgently needed.

Thai national guidelines for antiretroviral therapy in HIV-1 infected adults and adolescents 2010

In Thailand, more than 150,000 patients are currently treated with antiretroviral drugs under the support of the National AIDS Program (NAP). The appointed Adults and Adolescents Committee consisted of 28 members who are experts in HIV research, patient care or health care policy. Relevant published literature, guidelines, and the most recent relevant clinical trials presented internationally were reviewed. Several peer review and clinical studies conducted in Thailand were included in the review process. Special considerations for patients with co-infection of tuberculosis or hepatitis B were incorporated. Appropriate cut-off of CD4+ T-cell counts when to commence ART among Thai patients have been considered. It is now recommended to start ART at CD4+ T-cell count <350 cells/mm3. For treatment-naive patients, the preferred initial therapy is a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen containing lamivudine plus zidovudine or tenofovir. Stavudine will be phased out in a two-year plan at the national program level. Viral load and CD4+ T-cell counts should be monitored at least once and twice a year. To achieve long-term treatment success, enhancing adherence together with the proper management of antiretroviral-related toxicity is critical. In summary, the major changes from the Thai 2008 guidelines include commencing ART earlier. ART is recommended regardless of CD4+ T cell count if patients have an indication to treat their HBV co-infection. Preferred first regimen uses AZT or TDF, not d4T as the NRTI-backbone. Furthermore, efavirenz is now considered a preferred NNRTI, along with nevirapine.

Current trends and intricacies in the management of HIV-associated pulmonary tuberculosis

Human immunodeficiency virus (HIV) epidemic has undoubtedly increased the incidence of tuberculosis (TB) globally, posing a formidable global health challenge affecting 1.2 million cases. Pulmonary TB assumes utmost significance in the programmatic perspective as it is readily transmissible as well as easily diagnosable. HIV complicates every aspect of pulmonary tuberculosis from diagnosis to treatment, demanding a different approach to effectively tackle both the diseases. In order to control these converging epidemics, it is important to diagnose early, initiate appropriate therapy for both infections, prevent transmission and administer preventive therapy. Liquid culture methods and nucleic acid amplification tests for TB confirmation have replaced conventional solid media, enabling quicker and simultaneous detection of mycobacterium and its drug sensitivity profile Unique problems posed by the syndemic include Acquired rifampicin resistance, drug-drug interactions, malabsorption of drugs and immune reconstitution inflammatory syndrome or paradoxical reaction that complicate dual and concomitant therapy. While the antiretroviral therapy armamentarium is constantly reinforced by discovery of newer and safer drugs every year, only a few drugs for anti tuberculosis treatment have successfully emerged. These include bedaquiline, delamanid and pretomanid which have entered phase III B trials and are also available through conditional access national programmes. The current guidelines by WHO to start Antiretroviral therapy irrespective of CD4+ cell count based on benefits cited by recent trials could go a long way in preventing various complications caused by the deadly duo. This review provides a consolidated gist of the advancements, concepts and updates that have emerged in the management of HIV-associated pulmonary TB for maximizing efficacy, offering latest solutions for tackling drug-drug interactions and remedial measures for immune reconstitution inflammatory syndrome.

Integrated therapy for HIV and tuberculosis

Tuberculosis (TB) has been the most common opportunistic infection and cause of mortality among HIV-infected patients, especially in resource-limited countries. Clinical manifestations of TB vary and depend on the degree of immunodeficiency. Sputum microscopy and culture with drug-susceptibility testing are recommended as a standard method for diagnosing active TB. TB-related mortality in HIV-infected patients is high especially during the first few months of treatment. Integrated therapy of both HIV and TB is feasible and efficient to control the diseases and yield better survival. Randomized clinical trials have shown that early initiation of antiretroviral therapy (ART) improves survival of HIV-infected patients with TB. A delay in initiating ART is common among patients referred from TB to HIV separate clinics and this delay may be associated with increased mortality risk. Integration of care for both HIV and TB using a single facility and a single healthcare provider to deliver care for both diseases is a successful model. For TB treatment, HIV-infected patients should receive at least the same regimens and duration of TB treatment as HIV-uninfected patients. Currently, a 2-month initial intensive phase of isoniazid, rifampin, pyrazinamide, and ethambutol, followed by 4 months of continuation phase of isoniazid and rifampin is considered as the standard treatment of drug-susceptible TB. ART should be initiated in all HIV-infected patients with TB, irrespective of CD4 cell count. The optimal timing to initiate ART is within the first 8 weeks of starting antituberculous treatment and within the first 2 weeks for patients who have CD4 cell counts <50 cells/mm(3). Non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART remains a first-line regimen for HIV-infected patients with TB in resource-limited settings. Although a standard dose of both efavirenz and nevirapine can be used, efavirenz is preferred because of more favorable treatment outcomes. In the settings where raltegravir is accessible, doubling the dose to 800 mg twice daily is recommended. Adverse reactions to either antituberculous or antiretroviral drugs, as well as immune reconstitution inflammatory syndrome, are common in patients receiving integrated therapy. Early recognition and appropriate management of these consequences can reinforce the successful integrated therapy in HIV-infected patients with TB.

Guidelines for antiretroviral therapy in HIV-1 infected adults and adolescents 2014, Thailand

New evidence has emerged regarding when to commence antiretroviral therapy (ART), optimal treatment regimens, management of HIV co-infection with opportunistic infections, and management of ART failure. The 2014 guidelines were developed by the collaborations of the Department of Disease Control, Ministry of Public Health (MOPH) and the Thai AIDS Society (TAS). One of the major changes in the guidelines included recommending to initiating ART irrespective of CD4 cell count. However, it is with an emphasis that commencing HAART at CD4 cell count above 500 cell/mm³ is for public health, in term of preventing HIV transmission and personal benefit. In tuberculosis co-infected patients with CD4 cell counts ≤50 cells/mm³ or with CD4 cell counts >50 cells/mm³ who have severe clinical disease, ART should be initiated within 2 weeks of starting tuberculosis treatment. The preferred initial ART regimen in treatment naïve patients is efavirenz combined with tenofovir and emtricitabine or lamivudine. Plasma HIV viral load assessment should be done twice a year until achieving undetectable results; and will then be monitored once a year. CD4 cell count should be monitored every 6 months until CD4 cell count ≥350 cells/mm³ and with plasma HIV viral load <50 copies/mL; then it should be monitored once a year afterward. HIV drug resistance genotypic test is indicated when plasma HIV viral load >1,000 copies/mL while on ART. Ritonavir-boosted lopinavir or atazanavir in combination with optimized two nucleoside-analogue reverse transcriptase inhibitors is recommended after initial ART regimen failure. Long-term ART-related safety monitoring has also been included in the guidelines.

Nevirapine versus efavirenz-based antiretroviral therapy regimens in antiretroviral-naive patients with HIV and tuberculosis infections in India: a pilot study

Background

Administration of rifampicin along with nevirapine reduces the plasma concentration of nevirapine in human immunodeficiency virus positive individuals with concomitant tuberculosis (HIV-TB patients). Nevirapine is a much cheaper drug than its alternative efavirenz, and might be beneficial in resource constrained settings.

Methods

A randomised open label trial was conducted at All India Institute of Medical Sciences, New Delhi, India. During the regimen of an antiretroviral therapy (ART), naive HIV-TB patients were randomly assigned to receive either nevirapine or efavirenz based ART with concomitant rifampicin based anti-tubercular therapy (ATT). Participants were followed for 24 months after starting ART. The end points were virological, immunological and clinical responses, and progression of HIV disease marked by failure of ART.

Results

Of the 135 HIV-TB patients, who were receiving rifampicin based ATT, 68 were selected randomly to receive efavirenz based ART and 67 to receive nevirapine based ART. The virological failure rates in the overall population, and the nevirapine and efavirenz groups were 14.1% (19/135); 14.9% (10/67) and 13.2% (9/68), respectively (p = 0.94). No significant difference was found between the groups in the rate of clinical, immunological or virological failures. The overall mortality was 17% with no significant difference between the two groups. Except for the lead in period on day 14, the mean nevirapine concentration remained above 3 mg/L. No association was found between plasma levels of nevirapine and incidence of unfavourable outcomes in this group.

Conclusions

Outcome of ART in HIV-TB patients on rifampicin based ATT showed no significant difference, irrespective of whether efavirenz or nevirapine was used. Therefore, nevirapine based ART could be an alternative in the resource limited settings in patients with HIV and tuberculosis co-infection.

Trial registration

NCT No. 01805258.

Dose adjustment of the non-nucleoside reverse transcriptase inhibitors during concurrent rifampicin-containing tuberculosis therapy: one size does not fit all

IMPORTANCE OF THE FIELD

HIV/tuberculosis (TB) co-infection is common and associated with high mortality. Simultaneous highly active antiretroviral therapy during TB treatment is associated with substantial survival benefit but drug-drug interactions complicate NNRTI dosing.

AREAS COVERED IN THIS REVIEW

We reviewed the impact of rifampicin-containing TB therapy on the NNRTIs pharmacokinetics and clinical outcome. PubMed database was searched from 1966 to July 2009 using the terms efavirenz, rifampicin, nevirapine, pharmacokinetics, pharmacogenetics, HIV, TB, CYP2B6, CYP3A4 and metabolism. References from identified articles and abstracts from meetings were also reviewed.

WHAT THE READER WILL GAIN

A comprehensive review of the literature on this subject including pharmacokinetic and clinical studies. Most studies were small, observational or underpowered to detect the true effect of rifampicin on NNRTI-based therapy. None of the studies were controlled for genetic factors and there were limited data on children.

TAKE HOME MESSAGE

There were insufficient data to make definitive recommendations about dose adjustment of the NNRTIs during rifampin-containing therapy. Current data suggest that the standard dose of efavirenz or nevirapine is adequate in most HIV/TB co-infected adults. However, more research is needed in pediatric populations as well as to define role of drug-gene interactions.

Antiretroviral treatment changes in adults from Côte d'Ivoire: the roles of tuberculosis and pregnancy

OBJECTIVE

To determine the rates and causes of first antiretroviral treatment changes in HIV-infected adults in Côte d'Ivoire.

METHODS

We evaluated adults who initiated antiretroviral treatment in an outpatient clinic in Abidjan. We recorded baseline and follow-up data, including drug prescriptions and reasons for changing to alternative first-line regimens (drug substitution for any reason but failure) or second-line regimens (switch for failure).

RESULTS

Two thousand and twelve HIV-infected adults (73% women) initiated antiretroviral treatment. At baseline, 9% of all patients were on treatment for tuberculosis and 3% of women were pregnant. First-line antiretroviral treatment consisted of two nucleoside reverse transcriptase inhibitors (58% stavudine-lamivudine, 42% zidovudine-lamivudine) and efavirenz (63%), nevirapine (32%) or indinavir (5%). Median follow-up time was 16.9 months. During this time, 205 (10%) patients died and 261 (13%) were lost to follow-up. Overall, the rate of treatment modifications was 20.7/100 patient-years. The most common modifications were drug substitutions for intolerance (12.4/100 patient-years), pregnancy (4.5/100 patient-years) and tuberculosis (2.5/100 patient-years). The rates of intolerance-related substitutions were 17.9/100 patient-years for stavudine, 6.3/100 patient-years for nevirapine, 3.9/100 patient-years for zidovudine and 0.1/100 patient-years for efavirenz. Twenty percent of efavirenz substitutions resulted from pregnancy and 18% of nevirapine substitutions were related to tuberculosis treatment.

CONCLUSION

During the first months following antiretroviral treatment initiation, a third of all treatment changes occurred for reasons other than intolerance to the drug or treatment failure. In Africa, drug forecasting is crucial to ensuring the success of HIV treatment programmes. Drugs that do not require interruptions during pregnancy or tuberculosis treatment should be made more readily available as first-line drugs in sub-Saharan Africa.

HIV care and treatment factors associated with improved survival during TB treatment in Thailand: an observational study

Background

In Southeast Asia, HIV-infected patients frequently die during TB treatment. Many physicians are reluctant to treat HIV-infected TB patients with anti-retroviral therapy (ART) and have questions about the added value of opportunistic infection prophylaxis to ART, the optimum ART regimen, and the benefit of initiating ART early during TB treatment.

Methods

We conducted a multi-center observational study of HIV-infected patients newly diagnosed with TB in Thailand. Clinical data was collected from the beginning to the end of TB treatment. We conducted multivariable proportional hazards analysis to identify factors associated with death.

Results

Of 667 HIV-infected TB patients enrolled, 450 (68%) were smear and/or culture positive. Death during TB treatment occurred in 112 (17%). In proportional hazards analysis, factors strongly associated with reduced risk of death were ART use (Hazard Ratio [HR] 0.16; 95% confidence interval [CI] 0.07–0.36), fluconazole use (HR 0.34; CI 0.18–0.64), and co-trimoxazole use (HR 0.41; CI 0.20–0.83). Among 126 patients that initiated ART after TB diagnosis, the risk of death increased the longer that ART was delayed during TB treatment. Efavirenz- and nevirapine-containing ART regimens were associated with similar rates of adverse events and death.

Conclusion

Among HIV-infected patients living in Thailand, the single most important determinant of survival during TB treatment was use of ART. Controlled clinical trials are needed to confirm our findings that early ART initiation improves survival and that the choice of non-nucleoside reverse transcriptase inhibitor does not.

Durability of stavudine, lamivudine and nevirapine among advanced HIV-1 infected patients with/without prior co-administration of rifampicin: a 144-week prospective study

BACKGROUND

To date, data on the durability of a regimen of stavudine, lamivudine and nevirapine are very limited, particularly from the resource-limited settings.

METHODS

A prospective cohort study was conducted among 140 antiretroviral-naïve patients who were enrolled to initiate d4T, 3TC and NVP between November 2004 and March 2005. The objectives were to determine immunological and virological responses after 144 weeks of antiretroviral therapy. Seventy patients with tuberculosis also received rifampicin during the early period of antiviral treatment (TB group).

RESULTS

Of all, median (IQR) baseline CD4 cell count was 31 (14-79) cells/mm3; median (IQR) baseline HIV-1 RNA was 433,500 (169,000-750,000) copies/mL. The average body weight was 55 kilograms. By intention-to-treat analysis at 144 weeks, the overall percentage of patients who achieved plasma HIV-1 RNA <50 copies/mL was 59.3% (83/140). In subgroup analysis, 61.4% (43/70) patients in TB group and 57.1% (40/70) patients in control group achieved plasma HIV-1 RNA <50 copies/mL (RR = 1.194, 95%CI = 0.608-2.346, P = 0.731). Eight (5.8%) patients discontinued d4T due to neuropathy and/or symptomatic lactic acidosis.

CONCLUSION

The overall durability and efficacy of antiviral response of d4T, 3TC and NVP are satisfied and they are not different between HIV-1 infected patients with and without co-administration of rifampicin due to tuberculosis. However, stavudine-related adverse effects are concerns.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT00703898.

Population pharmacokinetics of nevirapine in combination with rifampicin-based short course chemotherapy in HIV- and tuberculosis-infected South African patients

OBJECTIVE

The aim was to develop a model to describe the population pharmacokinetics of nevirapine in South African human immunodeficiency virus (HIV)-infected patients who were taking nevirapine-based antiretroviral therapy concomitantly or in the absence of rifampicin-based tuberculosis therapy.

METHODS

Patients were divided into two groups: (1) patients receiving nevirapine-containing antiretroviral regimen (200 mg twice daily) and continuation phase rifampicin-containing tuberculosis therapy (n = 27) in whom blood samples were obtained before and not less than 14 days after they completed tuberculosis therapy; (2) patients without tuberculosis who were receiving a nevirapine-containing antiretroviral regimen for at least 3 weeks (n = 26). The population pharmacokinetics of nevirapine was described using nonlinear mixed effects modelling with NONMEM software. Based on the developed model, plasma concentration profiles after 300, 400 and 500 mg of nevirapine twice daily were simulated.

RESULTS

Concomitant administration of rifampicin increased nevirapine oral clearance (CL/F) by 37.4% and reduced the absorption rate constant (k(a)) by almost sixfold. Rifampicin reduced the nevirapine average minimum concentration by 39%. Simulated doses of 300 mg twice daily elevated nevirapine concentrations above subtherapeutic levels in most patients, with minimum exposure above the recommended maximum concentration. The area under the concentration-time curve of 12-hydroxynevirapine was not different in the presence of rifampicin. 2-, 3- and 8-Hydroxynevirapine were not detectable (LLOQ = 0.025 mg/L).

CONCLUSION

The developed model adequately describes nevirapine population pharmacokinetics in a South African population when taken with/and in the absence of rifampicin treatment. The simulations suggest that an increased dose of 300 mg twice daily would achieve adequate nevirapine concentrations in most patients during rifampicin-containing treatment for tuberculosis.

Pharmacokinetics and 48-Week Efficacy of Nevirapine: 400 mg Versus 600 mg per day in HIV–Tuberculosis Coinfection Receiving Rifampicin

Background

We aim here to determine the appropriate dose of nevirapine (NVP) in Thai HIV–tuberculosis (TB)-coinfected patients receiving rifampicin.

Methods

Thirty-two HIV-infected adults with CD4+ T-cell counts <200 cells/mm3 and active TB, receiving rifampicin for 2–6 weeks were randomized to receive either NVP 400 mg (NVP400) or 600 mg (NVP600) per day plus two nucleoside reverse transcriptase inhibitors; a 2-week NVP lead-in was performed at 200 mg once daily (OD) and 200 mg twice daily, respectively. Plasma NVP levels were determined at weeks 2, 4 and 12. Twelve-hour pharmacokinetics (PK) were obtained ( n=20) at week 4.

Results

Baseline body weight was comparable. There were more patients with NVP plasma concentration at 12 h (C12) <3.1 mg/l at week 2 in NVP400 than in NVP600 (79% versus 19%, respectively; P=0.002). However, the proportions were comparable at weeks 4 and 12. From week 4, 12 h PK studies showed that NVP400 had lower median NVP area under the plasma concentration-0–12 h (AUC0–12 h), maximum concentration in plasma (Cmax) and C12 than NVP600 ( P<0.05). Four patients in NVP600 developed NVP hypersensitivity. At week 48, the median CD4+ T-cell count rise and proportion with viral load <50 copies/ml (intention-to-treat analysis 56% versus 50% and as-treated analysis 75% versus 89%) were comparable.

Conclusions

In rifampicin-treated patients, 200 mg NVP OD lead-in led to a significant short-term suboptimal NVP C12 level, while NVP 400 mg lead-in then 600 mg/day was associated with a high rate of NVP hypersensitivity. Forty-eight week efficacy was comparable. Thus, NVP 600 mg/day in rifampicin-treated patients is not recommended.

Update on rifampin and rifabutin drug interactions

Rifampin is a potent inducer of cytochrome P-450 oxidative enzymes as well as the P-glycoprotein transport system. Several examples of well-documented clinically significant interactions include warfarin, oral contraceptives, cyclosporine, itraconazole, digoxin, verapamil, nifedipine, simvastatin, midazolam, and human immunodeficiency virus-related protease inhibitors. Rifabutin reduces serum concentrations of antiretroviral agents, but less so than rifampin. Examples of clinically relevant interactions demonstrated by recent reports include everolimus, atorvastatin, rosiglitazone/pioglitazone, celecoxib, clarithromycin, caspofungin, and lorazepam. To avoid a decreased therapeutic response, therapeutic failure, or toxic reactions when rifampin is added to or discontinued from medication regimens, clinicians need to be cognizant of these interactions. Studies and cases of rifampin drug interactions continue to increase rapidly. This review is a timely reminder to clinicians to be vigilant.

Challenges of Childhood TB/HIV Management in Malawi

The diagnosis and management of childhood tuberculosis (TB) are major challenges in countries such as Malawi with high incidence of TB and human immunodeficiency virus (HIV) infection. Diagnosis of TB in children often relies only on clinical features but clinical overlap with the presentation of HIV and other HIV-related lung disease is common. The tuberculin skin test (TST), the standard marker of M. tuberculosis infection in immune competent children, has poor sensitivity in HIV-infected children and is not usually available in Malawi. HIV test should be routine in children with suspected TB as it improves clinical management. HIV-infected children are at increased risk of developing active disease following TB exposure which justifies the use of isoniazid preventive therapy (IPT) once active disease has been excluded but this is difficult to implement and appropriate duration of IPT is unknown. HIV-infected children with active TB experience higher mortality and relapse rates on standard TB treatment compared to HIV-uninfected children, highlighting the need for further research to define optimal treatment regimens. HIV-infected children should also receive appropriate supportive care including cotrimoxazole prophylaxis and anti-retroviral treatment (ART) if indicated. There are concerns about concurrent use of some anti-TB drugs such as rifampicin with some ARTs.

Concurrent drug therapy for tuberculosis and HIV infection in resource-limited settings: present status and future prospects

Rapid scale-up of antiretroviral treatment (ART) in resource-limited settings where the burden of tuberculosis (TB) is high has resulted in the increasingly frequent need for patients to receive TB treatment and ART concurrently. This presents a major challenge to ART programs in these settings, where the therapeutic options and the healthcare infrastructure to effectively deliver and monitor overlapping treatment are limited. This article reviews the issues of pharmacokinetic interactions, drug cotoxicity and TB immune reconstitution disease. The currently available treatment options and the impact of concurrent treatment on patient outcomes are described. The use of ART in the treatment of HIV-associated multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) is also considered. Finally we discuss how new therapeutic agents currently in development may improve treatment options in the future.