Tenofovir-related Fanconi's syndrome and osteomalacia in a teenager with HIV

Polymer-Based Nanoparticles as Drug Delivery Systems for Purines of Established Importance in Medicine

Many purine derivatives are active pharmaceutical ingredients of significant importance in the therapy of autoimmune diseases, cancers, and viral infections. In many cases, their medical use is limited due to unfavorable physicochemical and pharmacokinetic properties. These problems can be overcome by the preparation of the prodrugs of purines or by combining these compounds with nanoparticles. Herein, we aim to review the scientific progress and perspectives for polymer-based nanoparticles as drug delivery systems for purines. Polymeric nanoparticles turned out to have the potential to augment antiviral and antiproliferative effects of purine derivatives by specific binding to receptors (ASGR1-liver, macrophage mannose receptor), increase in drug retention (in eye, intestines, and vagina), and permeation (intranasal to brain delivery, PEPT1 transport of acyclovir). The most significant achievements of polymer-based nanoparticles as drug delivery systems for purines were found for tenofovir disoproxil in protection against HIV, for acyclovir against HSV, for 6-mercaptopurine in prolongation of mice ALL model life, as well as for 6-thioguanine for increased efficacy of adoptively transferred T cells. Moreover, nanocarriers were able to diminish the toxic effects of acyclovir, didanosine, cladribine, tenofovir, 6-mercaptopurine, and 6-thioguanine.

Fanconi syndrome induced by the long-term use of tenofovir disoproxil fumarate: a case report and literature review

We present the case of a woman of 50 years of age who experienced widespread bone pain along with digestive symptoms, including nausea and vomiting. She had been prescribed tenofovir disoproxil fumarate (TDF) tablets for the treatment of hepatitis B. Laboratory testing revealed low circulating phosphorus and potassium concentrations and acidosis. A whole-body bone scan revealed abnormal bone metabolism. Rheumatologic and urologic conditions were ruled out, and therefore TDF-induced Fanconi syndrome (FS) and related bone pain was diagnosed. After the TDF was discontinued, the patient's symptoms and laboratory indices significantly improved. In this manuscript, we highlight the clinical manifestations of and laboratory test results associated with FS and summarize the cases of TDF-induced FS reported on PubMed between 2013 and 2022 to improve understanding of FS.

Tenofovir-Induced Delayed Nephro-Osteo Toxicity

Tenofovir disoproxil fumarate (TDF) is the foundation nucleotide reverse-transcriptase inhibitor in the recommended first-line regimen for all naive human immunodeficiency virus-1 (HIV-1) patients whose age is more than 10 years and body weight is more than 30 kg. Although it has a good safety profile overall, nephrotoxicity is a concern and its overall incidence is 1-6% with a long period of clinical latency. Nephrotoxicity may manifest as either proximal renal tubule dysfunction in the form of a partial or complete Fanconi syndrome or as decreased renal function leading to acute or chronic kidney injury. Osteomalacia can also develop secondary to complicating hypophosphataemia and low calcitriol levels. Here we report a 50-year-old HIV-positive male on tenofovir who presented with proximal renal tubular acidosis and fracture of left neck of femur four years after initiation of the drug.

Dual therapy with ritonavir-boosted protease inhibitor (PI) plus lamivudine versus triple therapy with ritonavir-boosted PI plus two nucleos(t)ide reverse-transcriptase inhibitor in HIV-infected patients with viral suppression

BACKGROUND

Dual antiretroviral regimens are attractive options to optimize the combination antiretroviral therapy in light of potential toxicities with long-term cumulative exposure to nucleos(t)ide reverse-transcriptase inhibitors (NRTIs).

METHODS

In this retrospective observational study, we included HIV-infected patients on suppressive antiretroviral therapy with plasma viral load (PVL) < 200 copies/mL for at least 6 months who were switched to dual regimens containing lamivudine (3TC) (150 mg twice daily or 300 mg once daily) plus lopinavir/ritonavir (LPV/r) 250/50 mg twice daily or darunavir/ritonavir (DRV/r) 800/100 mg once daily. Patients maintaining on suppressive triple therapy with DRV/r or LPV/r plus two NRTIs were included for comparisons. The primary endpoint was the proportion of patients with PVL <50 copies/mL after 48 weeks of follow-up.

RESULTS

In total, 364 patients were included with 93 (25.5%) switched to dual therapy After 48 weeks of observation, PVL <50 copies/mL was observed in 96.8% and 94.1% of dual-therapy and triple-therapy group, respectively, in per-protocol analysis (difference 2.7%; 95% CI -2.5%-7.9%). Nineteen patients (3 [3.2%] in dual-therapy and 16 [7.6%] in triple-therapy group) developed virologic failure, with none having emergent M184V resistance-associated mutation. A statistically significant increase of cholesterol level (13 mg/dL versus 2 mg/dL, p = 0.003) and high-density lipoprotein (3 mg/dL versus -2 mg/dL, p = 0.019) were observed in dual-therapy than in triple-therapy group. Changes of triglyceride, low-density lipoprotein and glycated hemoglobin levels were similar between the two groups.

CONCLUSION

Dual therapy with DRV/r or LPV/r plus lamivudine demonstrated similar effectiveness in maintaining viral suppression to triple therapy.

Tenofovir Has Minimal Effect on Biomarkers of Bone Health in Youth with HIV Receiving Initial Antiretroviral Therapy

Both HIV infection and tenofovir disoproxil fumarate (TDF) treatment adversely impact bone metabolism and may lead to osteopenia, which has critical implications for youth with HIV (YWH). This study evaluates changes in the biomarkers of bone metabolism and inflammation among YWH receiving initial treatment with TDF- and non-TDF-containing antiretroviral therapies (ARTs). YWH [n = 23, median age 21 years (range 18-24), 87% male, 61% African American] were assessed for inflammatory and bone metabolism biomarkers at enrollment, after 48 weeks of TDF-containing ART, and 96 weeks of ART without TDF with continued viral suppression. Spearman's rank correlation evaluated biomarker associations. Bone alkaline phosphatase, parathyroid hormone, and osteopontin increased after TDF treatment. All fell after TDF was discontinued. Levels of RANKL and osteoprotegerin did not change throughout the study. There was little correlation between biomarkers of bone metabolism and either macrophage or lymphocyte activation at any time point. Our results establish baseline associations between bone metabolism and immune biomarkers for this population, and find that before CD4 T cell decline chronic inflammation does not perturb biomarkers of bone metabolism among YWH. The adverse effects of TDF on bone health may be marginal for YWH at the early stages of disease.

Bone Loss in HIV Infection

Human immunodeficiency virus (HIV) infection is an established risk factor for low bone mineral density (BMD) and subsequent fracture, and treatment with combination antiretroviral therapy (cART) leads to additional BMD loss, particularly in the first 1-2 years of therapy. The prevalence of low BMD and fragility fracture is expected to increase as the HIV-infected population ages with successful treatment with cART. Mechanisms of bone loss in the setting of HIV infection are likely multifactorial, and include viral, host, and immune effects, as well as direct and indirect effects of cART, particularly tenofovir disoproxil fumarate (TDF) and the protease inhibitors (PIs). Emerging data indicate that BMD loss following cART initiation can be mitigated by prophylaxis with either long-acting bisphosphonates or vitamin D and calcium supplementation. In addition, newer antiretrovirals, particularly the integrase strand transfer inhibitors and tenofovir alafenamide (TAF), are associated with less intense bone loss than PIs and TDF. However, further studies are needed to establish optimal bone sparing cART regimens, appropriate screening intervals, and preventive measures to address the rising prevalence of fragility bone disease in the HIV population.

Effect of high-dose cholecalciferol (vitamin D3) on bone and body composition in children and young adults with HIV infection: a randomized, double-blind, placebo-controlled trial

It is unknown whether vitamin D supplementation positively impacts body composition and bone outcomes in children and young adults with HIV. This RCT found that despite increasing 25(OH)D concentrations, high dose vitamin D₃ supplementation did not impact bone or body composition in children and young adults with HIV infection.

INTRODUCTION

The objective of this paper was to determine the impact of high-dose daily cholecalciferol (vitamin D₃) supplementation on body composition and bone density, structure, and strength in children and young adults with perinatally acquired (PHIV) or behaviorally acquired (BHIV) HIV infection.

METHODS

Participants were randomized to receive vitamin D₃ supplementation (7000 IU/day) or placebo for 12 months. Serum 25-hydroxyvitamin D [25(OH)D] concentrations, dual energy X-ray absorptiometry (DXA) of the whole body and lumbar spine, and peripheral quantitative computed tomography (pQCT) of tibia sites were acquired at 0, 6, and 12 months. DXA and pQCT outcomes were expressed as sex- and population-ancestry specific Z-scores relative to age and adjusted for height or tibia length, as appropriate.

RESULTS

Fifty-eight participants (5.0 to 24.9 years) received vitamin D₃ supplements (n = 30) or placebo (n = 28). At enrollment, groups were similar in age, sex, population ancestry, growth status, serum 25(OH)D concentrations, body composition, and size-adjusted bone measures. Median 25(OH)D concentrations were similar (17.3 ng/mL in the vitamin D₃ supplementation group vs 15.6 ng/mL in the placebo group), and both groups had mild bone deficits. At 12 months, 25(OH)D rose significantly in the vitamin D supplementation group but not in the placebo group (26.4 vs 14.8 ng/mL, respectively, p < 0.008). After adjusting for population ancestry, sex, antiretroviral therapy use, and season, there were no significant treatment group differences in bone or body composition outcomes.

CONCLUSIONS

Despite increasing 25(OH)D concentrations, 12 months of high-dose vitamin D₃ supplementation did not impact bone or body composition in children and young adults with HIV infection.

Renal and Bone Adverse Effects of a Tenofovir-Based Regimen in the Treatment of HIV-Infected Children: A Systematic Review

INTRODUCTION

Tenofovir disoproxil fumarate (TDF)-containing regimens in the treatment of HIV-infected children have safety concerns with respect to renal and bone toxicity.

OBJECTIVE

The aim of this study was to systematically review and critically appraise the literature relating to the reported renal and bone adverse effects of TDF-based regimens in the treatment of HIV-infected children from 2 to 19 years old.

METHODS

Searches were performed using the Cochrane Central Register of Controlled Trials (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, OvidSP, ScienceDirect and Web of Science databases and platforms. All primary studies involving tenofovir use in HIV-infected children were sought. Studies that involved the use of TDF for pre- and post-exposure prophylaxis, and treatment of chronic hepatitis B virus infection were excluded. Data on study characteristics, participant's characteristics, therapeutic intervention and adverse effects were extracted using a piloted tool. In addition, pharmacovigilance data from the WHO Adverse Reaction database were included.

RESULTS

We identified 19 studies that reported the presence of renal and bone adverse effects of TDF and these included a total of 1100 study participants. The reports were in distinctly heterogeneous participant groups. A total of 287 renal and bone adverse effects were reported (250 renal and 37 bone adverse effects). Approximately 238 (21.6 %) participants were affected by these adverse effects. Of these, 15 participants stopped their TDF-containing regimen due to these adverse effects. In addition, the pharmacovigilance data from the WHO Adverse Reaction database reported 101 renal and bone adverse effects for patients whose indication was HIV/AIDS.

CONCLUSION

This systematic review summarises the reports of renal and bone adverse effects of a TDF-containing regimen in the treatment of HIV-infected children. Our findings suggest that the benefits of using TDF in children need to be balanced against the potential risk of toxicity.

Tenofovir and bone health

PURPOSE OF REVIEW

With continued improvements to the antiviral efficacy and tolerability of antiretroviral therapy, long-term safety of antiretroviral therapy has become paramount. Low bone mineral density and fragility fractures are more common in HIV-infected individuals than in the general population. The aims of this review are to describe potential mechanisms underlying the adverse effects of tenofovir on bone, clinical studies of tenofovir disoproxil fumarate (TDF) and bone, and more recent bone data on tenofovir alafenamide.

RECENT FINDING

Several studies have demonstrated an approximately 1-3% greater bone mineral density loss with TDF compared with other agents. Recent studies with tenofovir alafenamide have shown improved bone (and renal) safety with similar virologic efficacy when compared to TDF.

SUMMARY

Given these findings, TDF-containing regimens may be gradually replaced with non-TDF containing regimens for the treatment of HIV infection, especially in those at higher risk for fragility fracture.

Distal renal tubular acidosis without renal impairment after use of tenofovir: a case report

BACKGROUND

Tenofovir, one of antiretroviral medication to treat human immunodeficiency virus (HIV) infection, is known to cause proximal renal tubular acidosis such as Fanconi syndrome, but cases of distal renal tubular acidosis had never been reported.

CASE PRESENTATION

A 20-year-old man with HIV infection developed nausea and vomiting without diarrhea after starting antiretroviral therapy. Arterial blood gas revealed non-anion-gap metabolic acidosis and urine test showed positive urine anion gap. Tenofovir, one of antiretroviral medicine the patient received, was considered to be the cause of this acidosis and all antiretroviral drugs were discontinued. Symptoms disappeared promptly without recurrence of symptoms after resuming antiretroviral medications without tenofovir.

CONCLUSION

Distal renal tubular acidosis caused by tenofovir, without renal impairment is very rare. Since causes of nausea and vomiting among HIV/AIDS patients are very diverse, awareness of this phenomenon is useful in diagnosing and managing the problem.

Drug-Induced Metabolic Acidosis

Metabolic acidosis could emerge from diseases disrupting acid-base equilibrium or from drugs that induce similar derangements. Occurrences are usually accompanied by comorbid conditions of drug-induced metabolic acidosis, and clinical outcomes may range from mild to fatal. It is imperative that clinicians not only are fully aware of the list of drugs that may lead to metabolic acidosis but also understand the underlying pathogenic mechanisms. In this review, we categorized drug-induced metabolic acidosis in terms of pathophysiological mechanisms, as well as individual drugs’ characteristics.

Prevalence of lipodystrophy and metabolic abnormalities in HIV-infected African children after 3 years on first-line antiretroviral therapy

BACKGROUND

Most pediatric lipodystrophy data come from high-income/middle-income countries, but most HIV-infected children live in sub-Saharan Africa, where lipodystrophy studies have predominantly investigated stavudine-based regimens.

METHODS

Three years after antiretroviral therapy (ART) initiation, body circumferences and skinfold thicknesses were measured (n = 590), and fasted lipid profile assayed (n = 325), in children from 2 ARROW trial centres in Uganda/Zimbabwe. Analyses compared randomization to long-term versus short-term versus no zidovudine from ART initiation [unadjusted; latter 2 groups receiving abacavir+lamivudine+non-nucleoside-reverse-transciptase-inhibitor (nNRTI) long-term], and nonrandomized (confounder-adjusted) receipt of nevirapine versus efavirenz.

RESULTS

Body circumferences and skinfold thicknesses were similar regardless of zidovudine exposure (P > 0.1), except for subscapular and supra-iliac skinfolds-for-age which were greater with long-term zidovudine (0.006 < P < 0.047). Circumferences/skinfolds were also similar with efavirenz and nevirapine (adjusted P > 0.09; 0.02 < P < 0.03 for waist/waist-hip-ratio). Total and high-density lipoprotein (HDL)-cholesterol, HDL/triglyceride-ratio (P < 0.0001) and triglycerides (P = 0.01) were lower with long-term zidovudine. Low-density lipoprotein (LDL)-cholesterol was higher with efavirenz than nevirapine (P < 0.001). Most lipids remained within normal ranges (75% cholesterol, 85% LDL and 100% triglycerides) but more on long-term zidovudine (3 NRTI) had abnormal HDL-cholesterol (88% vs. 40% short/no-zidovudine, P < 0.0001). Only 8/579(1.4%) children had clinical fat wasting (5 grade 1; 3 grade 2); 2(0.3%) had grade 1 fat accumulation.

CONCLUSIONS

Long-term zidovudine-based ART is associated with similar body circumferences and skinfold thicknesses to abacavir-based ART, with low rates of lipid abnormalities and clinical lipodystrophy, providing reassurance where national programs now recommend long-term zidovudine. Efavirenz and nevirapine were also similar; however, the higher LDL observed with efavirenz and lower HDL observed with zidovudine suggests that zidovudine+lamivudine+efavirenz should be investigated in future.