Prior exposure to thymidine analogs and didanosine is associated with long-lasting alterations in adipose tissue distribution and cardiovascular risk factors.

BACKGROUND: Thymidine analogs and didanosine (ddI) have been associated with redistribution of body fat from subcutaneous adipose tissue (SAT) to visceral adipose tissue (VAT), which, in turn, is a risk factor for cardiovascular disease. We explored differences in adipose tissue distribution between people living with HIV (PLWH) with prior exposure to thymidine analogs and/or ddI, without exposure, and uninfected controls and the association with cardiovascular disease risk factors. METHODS: In all, 761 PLWH from the Copenhagen Comorbidity in HIV Infection study, and 2283 age and sex-matched uninfected controls from the Copenhagen General Population Study were included. PLWH were stratified according to prior exposure to thymidine analogs and/or ddI. VAT and SAT were determined by abdominal computed tomography scan. Hypotheses were tested using regression analyses. RESULTS: Exposure to thymidine analogs and/or ddI was associated with 21.6 cm larger VAT (13.8-29.3) compared to HIV infection without exposure. HIV-negative status was associated with similar VAT compared to HIV infection without exposure. Cumulative exposure to thymidine analogs and/or ddI [3.7 cm per year (2.3-5.1)], but not time since discontinuation [-1.1 cm per year (-3.4 to 1.1)], was associated with VAT. Prior exposure to thymidine analogs and/or ddI was associated with excess risk of hypertension [adjusted odds ratio (aOR) 1.62 (1.13-2.31)], hypercholesterolemia [aOR 1.49 (1.06-2.11)], and low high-density lipoprotein [aOR 1.40 (0.99-1.99)]. CONCLUSIONS: This study suggests a potentially irreversible and harmful association of thymidine analogs and ddI with VAT accumulation, which appears be involved in the increased risk of hypertension, hypercholesterolemia, and low high-density lipoprotein found in PLWH with prior exposure to thymidine analogs and/or ddI, even years after treatment discontinuation.

An association between K65R and HIV-1 subtype C viruses in patients treated with multiple NRTIs.

Objectives: HIV-1 subtype C might have a greater propensity to develop K65R mutations in patients with virological failure compared with other subtypes. However, the strong association between viral subtype and confounding factors such as exposure groups and ethnicity affects the calculation of this propensity. We exploited the diversity of viral subtypes within the UK to undertake a direct comparative analysis. Patients and methods: We analysed only sequences with major IAS-defined mutations from patients with virological failure. Prevalence of K65R was related to subtype and exposure to the NRTIs that primarily select for this mutation (tenofovir, abacavir, didanosine and stavudine). A multivariate logistic regression model quantified the effect of subtype on the prevalence of K65R, adjusting for previous and current exposure to all four specified drugs. Results: Subtype B patients ( n = 3410) were mostly MSM (78%) and those with subtype C ( n = 810) were mostly heterosexual (82%). K65R was detected in 7.8% of subtype B patients compared with 14.2% of subtype C patients. The subtype difference in K65R prevalence was observed irrespective of NRTI exposure and K65R was frequently selected by abacavir, didanosine and stavudine in patients with no previous exposure to tenofovir. Multivariate logistic regression confirmed that K65R was significantly more common in subtype C viruses (adjusted OR = 2.02, 95% CI = 1.55-2.62, P < 0.001). Conclusions: Patients with subtype C HIV-1 have approximately double the frequency of K65R in our database compared with other subtypes. The exact clinical implications of this finding need to be further elucidated.

New-onset diabetes in HIV-treated adults: predictors, long-term renal and cardiovascular outcomes.

OBJECTIVE: To determine the incidence and risk factors for developing diabetes mellitus in a cohort of Thai HIV-infected patients on long-term combination antiretroviral therapy (cART). DESIGN: Prospective study conducted between July 1996 and 30 April 2015. METHODS: A total of 1748 patients (60% men) who did not have diabetes mellitus prior to ART were assessed twice a year. Incident diabetes mellitus was defined as either having two consecutive fasting glucose levels more than 126 mg/dl, or reporting antidiabetes mellitus medication/diabetes mellitus diagnosis after starting cART. Incidence rates were calculated per 1000 person-year follow-up. Multivariate Cox regression was used to determine risk factors for the development of diabetes mellitus. RESULTS: During a median follow-up of 9 years (16 274 person-year of follow-up), 123 patients developed new-onset diabetes mellitus, resulting in an incidence rate of 7.6 (95% confidence interval 6.3-9) per 1000 person-year of follow-up. From the multivariate models, age more than 35 years, male sex, BMI at least 25 kg/m, family history of diabetes, abnormal waist circumference, lipodystrophy and exposure to didanosine were significantly associated with incident diabetes mellitus. The diabetes mellitus group had higher mortality rate (8.1 vs. 4.1%, P = 0.04). A significantly higher proportion diabetes vs. nondiabetes patients developed cardiovascular and cerebrovascular complications (8.9 vs. 3.6%, P = 0.008) or chronic kidney disease stage III (estimated glomerular filtration rate <60 ml/min/1.73 m) (15.3 vs. 1.9%, P < 0.001) over total follow-up. CONCLUSION: In addition to traditional risk factors, lipodystrophy and use of didanosine were strongly associated with development of incident diabetes. Given the higher rate of cardiovascular-cerebrovascular complications and chronic kidney disease among patients with diabetes mellitus, careful assessment and appropriate management of diabetes mellitus are essential.

DIDANOSINE RETINAL TOXICITY.

PURPOSE: To report nine new cases of retinal degeneration secondary to didanosine toxicity and to summarize the previously reported cases in the literature. METHODS: This was a multicenter, retrospective, observational case study from seven institutions. Medical records of patients who demonstrated well-demarcated severe midperipheral chorioretinal degeneration and who were previously treated with didanosine therapy were collected and the following information was reviewed: age, gender, medical history, detailed medication history including current and previous antiretroviral use, ocular and retinal examination findings, and multimodal imaging findings with optical coherence tomography, fundus photography, wide-field fundus autofluorescence, and wide-field fluorescein angiography. When available, findings with electrophysiology testing and automated perimetry were also collected and reviewed. A literature review was also performed to collect all reported cases of chorioretinal degeneration secondary to didanosine toxicity. RESULTS: Nine patients were identified who had findings consistent with peripheral retinal toxicity secondary to didanosine use. Eight of the 9 patients were men, and the median age was 54 years at the time of presentation (mean: 55 years, range, 42-71 years). Snellen distance acuity ranged from 20/20 to 20/32. At least three of the cases in the series demonstrated progression of the peripheral retinal pigment epithelium and photoreceptor atrophy despite didanosine cessation. A review of the literature revealed 10 additional cases of didanosine toxicity. Seven of the 10 cases were in men (70%), and the average age was 26 years with a wide range (2-54 years). Chorioretinal findings were very similar to this cohort. CONCLUSION: Herein, we report the largest series of nine cases of peripheral chorioretinal degeneration secondary to didanosine toxicity in adults. When combined with the cases in the literature, 19 cases of didanosine toxicity, 4 of which occurred in children, were collected and analyzed. Three of the new cases presented showed clear progression of degeneration despite didanosine cessation. Newer nucleoside reverse transcriptase inhibitors may potentiate mitochondrial DNA damage and lead to continued chorioretinal degeneration.

Efavirenz Capsule Sprinkle and Liquid Formulations With Didanosine and Emtricitabine in HIV-1-infected Infants and Children 3 Months to 6 Years of Age: Study AI266-922.

BACKGROUND: AI266-922 was an open-label, dose-ranging study that assessed the pharmacokinetics, safety and efficacy of efavirenz (EFV) in children (3 months to 6 years). METHODS: Antiretroviral-naïve and antiretroviral-experienced HIV-1-infected children received once-daily EFV as oral solution or capsule sprinkle plus didanosine and emtricitabine (FTC). Pharmacokinetic analyses were undertaken at week 2 and repeated at weeks 10 and 18 after an EFV dose change or switch from oral solution to capsule sprinkle. RESULTS: Thirty-seven subjects were treated. EFV area under the plasma concentration-time curve over 1 dosing interval from time 0 to 24 hours postdose values were generally suboptimal (<110 µM × h) in subjects younger than 3 years treated with oral solution; these subjects switched to capsule sprinkle. Twenty of 21 subjects younger than 3 years treated with capsule sprinkle achieved an EFV area under the plasma concentration-time curve over 1 dosing interval from time 0 to 24 hours postdose value >110 µM × h, although higher initial doses were administered in this age group. Interpatient variability in EFV exposure was high. By week 48, 77.8% and 63.0% of subjects achieved HIV-RNA <400 and <50 copies/mL, respectively. Median changes in log10 HIV-RNA and CD4 percentage from baseline were -3.18 copies/mL and +6%, respectively. Two (5.4%) patients discontinued because of adverse events (AEs). Serious AEs occurred in 20 (54.1%) subjects. Common AEs were diarrhea (49%), nasopharyngitis (35%) and pneumonia (30%). Overall, 43% of subjects with suboptimal EFV exposure at week 2 developed resistance. CONCLUSIONS: Once-daily EFV, given as capsule sprinkle, achieved target exposures in this study although doses were 2-3 times higher than Food and Drug Administration-approved doses for children younger than 3 years. These data are useful for dose selection modeling and simulation; however, Food and Drug Administration-approved doses should be used clinically. EFV + didanosine + FTC was efficacious with no new pediatric safety findings reported.

Didanosine-loaded chitosan microspheres optimized by surface-response methodology: a modified "Maximum Likelihood Classification" approach formulation for reverse transcriptase inhibitors.

Didanosine-loaded chitosan microspheres were developed applying a surface-response methodology and using a modified Maximum Likelihood Classification. The operational conditions were optimized with the aim of maintaining the active form of didanosine (ddI), which is sensitive to acid pH, and to develop a modified and mucoadhesive formulation. The loading of the drug within the chitosan microspheres was carried out by ionotropic gelation technique with sodium tripolyphosphate (TPP) as cross-linking agent and magnesium hydroxide (Mg(OH)2) to assure the stability of ddI. The optimization conditions were set using a surface-response methodology and applying the "Maximum Likelihood Classification", where the initial chitosan concentration, TPP and ddI concentration were set as the independent variables. The maximum ddI-loaded in microspheres (i.e. 1433 mg of ddI/g chitosan), was obtained with 2% (w/v) chitosan and 10% TPP. The microspheres depicted an average diameter of 11.42 µm and ddI was gradually released during 2 h in simulated enteric fluid.

In vitro comparative evaluation of monolayered multipolymeric films embedded with didanosine-loaded solid lipid nanoparticles: a potential buccal drug delivery system for ARV therapy.

Drug delivery via the buccal route has emerged as a promising alternative to oral drug delivery. Didanosine (DDI) undergoes rapid degradation in the gastrointestinal tract, has a short half-life and low oral bioavailability, making DDI a suitable candidate for buccal delivery. Recent developments in buccal drug delivery show an increased interest toward nano-enabled delivery systems. The advantages of buccal drug delivery can be combined with that of nanoparticulate delivery systems to provide a superior delivery system. The aim of this study was to design and evaluate the preparation of novel nano-enabled films for buccal delivery of DDI. Solid lipid nanoparticles (SLNs) were prepared via hot homogenization followed by ultrasonication and were characterized before being incorporated into nano-enabled monolayered multipolymeric films (MMFs). Glyceryl tripalmitate with Poloxamer 188 was identified as most suitable for the preparation of DDI-loaded SLNs. SLNs with desired particle size (PS) (201 nm), polydispersity index (PDI) (0.168) and zeta potential (-18.8 mV) were incorporated into MMFs and characterized. Conventional and nano-enabled MMFs were prepared via solvent casting/evaporation using Eudragit RS100 and hydroxypropyl methylcellulose. Drug release from the nano-enabled films was found to be faster (56% versus 20% in first hour). Conventional MMFs exhibited higher mucoadhesion and mechanical strength than nano-enabled MMFs. SLNs did not adversely affect the steady state flux (71.63 ± 13.54 µg/cm(2) h versus 74.39 ± 15.95 µg/cm(2) h) thereby confirming the potential transbuccal delivery of DDI using nano-enabled MMFs. Nano-enabled buccal films for delivery of DDI can be successfully prepared, and these physico-mechanical studies serve as a platform for future formulation optimization work in this emerging field.

Novel oleic acid derivatives enhance buccal permeation of didanosine.

The aim of this study was to explore the potential of novel oleic acid (OA) derivatives as buccal permeation enhancers for the delivery of didanosine (ddI). The OA derivatives, i.e. ester derivative (OA1E), the dicarboxylic acid derivative (OA1A) and the bicephalous dianionic surfactant (OA1ANa) were synthesized and their effects were compared to the parent OA. OA, OA1E, OA1A and OA1ANa at 1% w/w all showed potential for enhancing the buccal permeability of ddI with enhancement ratio (ER) of 1.29, 1.33, 1.01 and 1.72, respectively. OA1ANa at 1% w/w demonstrated the highest flux (80.30 ± 10.37 µg cm(-2 )h), permeability coefficient (4.01 ± 0.57 × 10(-3) cm h(-1)) and ER (1.72). The highest flux for ddI (144.00 ± 53.54 µg cm(-2 )h) was reported with OA1ANa 2% w/w, which displayed an ER of 3.09 more than that with ddI alone. At equivalent concentrations, OA1ANa (ER = 3.09) had a significantly higher permeation-enhancing effect than its parent OA (ER = 1.54). Histomorphological studies confirmed that OA1ANa at all concentrations (0.5, 2.0 and 6.0% w/w) had no adverse effects on the mucosae. Morphological changes such as vacuoles formation and increased intercellular spaces were attributed to the buccal permeation-enhancing effect of OA1ANa. This study demonstrated the potential of novel OA derivatives as buccal permeation enhancers. OA1ANa at 2% w/w was also identified as the optimal novel OA derivative to widen the pool of fatty acid derivatives as chemical permeation enhancers for buccal drug delivery.

Comparative buccal permeability enhancement of didanosine and tenofovir by potential multifunctional polymeric excipients and their effects on porcine buccal histology.

This study identified and compared the buccal permeability properties of antiretroviral drugs, didanosine (ddI) and tenofovir (TNF), and the permeability effects of polymeric excipients - i.e. carboxymethylcellulose (CMC), sodium alginate (SA), polyacrylic acid (PAA) and polyethylene glycol (PEG) - as potential multifunctional excipients for buccal drug delivery. Permeation studies across porcine buccal mucosa were performed and the drug was quantified using UV spectrophotometry. The mean flux for both ddI (113-181 µg/cm(2)h) and TNF (40-102 µg/cm(2)h) increased linearly with increasing donor concentration. All polymeric excipients improved permeability of TNF while only PEG was effective for ddI. Permeability enhancement ratios at 20 mg/mL for ddI and TNF were 1.63 and 1.74, respectively, using PEG (0.5% w/v) and CMC (0.5% w/v), respectively. The maximum enhancement ratio of 2.13 for TNF was achieved with 4% w/v PEG. Light and transmission electron microscopy revealed no significant loss in cellular integrity of mucosa treated with either TNF or ddI alone or when coupled with PEG as a polymeric enhancer. Histomorphological observations correlated with flux values obtained for TNF and ddI alone, as well as with PEG's effects on drug mass flux. TNF and ddI have demonstrated buccal delivery potential. Selective polymeric excipients provide an effective means to increase their penetration and may serve as potential formulation multifunctional excipients in a delivery system for delivery via the buccal route.

24-Month adherence, tolerance and efficacy of once-a-day antiretroviral therapy with didanosine, lamivudine, and efavirenz in African HIV-1 infected children: ANRS 12103/12167.

BACKGROUND: There is no data on long-term benefit of once-a-day antiretroviral therapy (ART) with combination of DDI, 3TC and EFV to allow its use in future therapeutic strategies. OBJECTIVES: To assess 24-month immuno-virological, adherence, tolerance, and effectiveness of a once-a-day ART with DDI, 3TC and EFV. METHODS: A phase 2 open trial including 51 children aged from 30 months to 15 years, monitored a once-a-day regimen for 24 months from 2006 to 2008 in the Departement de Pediatrie du CHUSS, at Bobo-Dioulasso in Burkina Faso. We tested immunological and virological response, adherence, tolerance and resistance of the treatment. RESULTS: Children with CD4 >25% at 24 months were 67.4% (33/49) CI 95% [54%, 80%]. The proportion of children with viral plasma RNA <300 cp / ml at 24 months of treatment was 81.6 % (40/49) CI [68.0% 91.2%]. Good adherence was obtained with more than 88% adherence > 95% over the 24 months. Drugs were well tolerated. CONCLUSIONS: Given the limited number of antiretroviral drugs available in Africa and the inadequacy of laboratory monitoring in support program, once-a-day treatment and especially the DDI-based combination strategies could be an attractive operational option.

Monolayered multipolymeric buccal films with drug and polymers of opposing solubilities for ARV therapy: physico-mechanical evaluation and molecular mechanics modelling.

Although buccal permeation investigations with antiretroviral drug solutions have confirmed their transbuccal delivery potential, studies on their formulation into delivery systems are lacking. Multipolymeric monolayered films (MMFs) with drugs and polymers of opposing solubilities will offer several advantages for the controlled release delivery of didanosine (DDI) via the buccal route. The aim of this study was to employ a co-blending-co-plasticization technique for preparation of MMFs containing Eudragit(®) RS 100 (EUD) and Hydroxypropyl methylcellulose (HPMC) and to undertake molecular modelling and in vitro characterizations. Uniform drug content (91-105%) with low variability was obtained for all films. Co-blending of DDI:HPMC:EUD (1:1:10) was required to achieve controlled drug release. The buccal permeability potential of DDI from the MMFs was successfully demonstrated with a permeability coefficient of 0.72±0.14×10(-2) cm/h and a steady state flux of 71.63±13.54 µg/cm(2) h. Films had acceptable mucoadhesivity (2184 mN), mechanical strength (0.698 N/mm(2)) and surface pH (6.63). The mechanism inherent to the mucoadhesive and drug release profile performance of the MMFs was elucidated via static lattice molecular mechanics simulations wherein a close corroboration among the in vitro-in silico (IVIS) data was observed. These extensive physico-mechanical and molecular atomistic studies have confirmed the use of MMFs containing DDI, HPMC and EUD as a buccal delivery system.

A novel pharmacokinetic approach to predict virologic failure in HIV-1-infected paediatric patients.

OBJECTIVE: The objective of this study was to develop in children an HIV dynamic model able to predict simultaneously the viral load and CD4 lymphocyte evolutions, and to take into account, through a composite inhibition score, the relative contribution of each drug of the combination efavirenz-didanosine-lamivudine and use this score as a predictor of treatment failure in a multidrug therapy. DESIGN: Open phase II trial (BURKINAME - ANRS 12103) registered in the ClinicalTrials.gov database (http://clinicaltrials.gov) with the no. NCT00122538. METHODS: Forty-nine children aged from 2.5 to 15 years were administered once-daily dose of lamivudine, didanosine and efavirenz. The three drugs effect was then characterized by a composite inhibition score combining the effect of each drug, according to their site and mechanism of action and their relative contribution. RESULTS: Efavirenz was the most potent antiretroviral and was responsible for 65% of the total effect, and then didanosine for 23% and lamivudine was the less potent with 12% of the total observed effect. An EC90 for efavirenz was determined (3.3 mg/l). AUC90 was estimated for lamivudine and didanosine: 8.4 and 1.5 mg h/l, respectively. The composite inhibition score was the best predictor of virologic failure compared with the concentrations of each drug taken independently [hazard ratio (HR) 0.6 per 10% increase, 95% confidence interval (CI) 0.41-0.88]. CONCLUSION: The relative contributions of three combined drugs were assessed on plasma viral load and CD4 lymphocyte count kinetics in HIV-1-infected children. Pharmacokinetics targets have been suggested for lamivudine and didanosine. A composite inhibition score has been determined to be a high predictor of treatment failure in a multidrug therapy.

Pancreatic insufficiency in patients with HIV infection: role of didanosine questioned.

OBJECTIVES: The aim of the study was to identify possible causes of pancreatic insufficiency in patients with HIV infection. METHODS: A retrospective analysis of 233 HIV-positive patients for whom faecal elastase measurement was available was performed to investigate potential associations with core demographic data, HIV infection characteristics, degree of immunosuppresion, exposure to antiretroviral therapy (ART), alcohol misuse, diabetes, hepatitis C virus (HCV) infection, triglyceride and cholesterol levels and symptomatology. The response to pancreatic enzyme replacement for patients with evidence of insufficiency was also evaluated. RESULTS: Of 233 patients, 104 (45%) had evidence of pancreatic exocrine insufficiency (faecal elastase < 200 mcg/g). A positive association with exocrine pancreatic insufficiency was found for HCV infection (P = 0.007), previous or current HCV treatment (P = 0.003), alcohol misuse history (P = 0.006) and the presence of steatorrhoea (P = 0.03). There was no demonstrated association between exocrine pancreatic insufficiency and didanosine (ddI) exposure (P = 0.43) or stavudine (d4T) exposure (P = 0.62). Seventy-seven per cent of patients who were treated with pancreatic enzymatic supplementation reported a subjective improvement in symptoms. CONCLUSIONS: Faecal elastase sampling should form part of the routine work-up for HIV-positive patients with chronic diarrhoea even in the absence of 'traditional' risk factors such as ddI exposure. In particular, if the patient has steatorrhoea, a history of alcohol exposure or their HCV serology is positive, they should be considered for investigation. Treatment with pancreatic enzyme supplementation appears to be effective in the treatment of chronic diarrhoea caused by pancreatic insufficiency in the majority of patients.

Didanosine (ddI) associates with increased liver fibrosis in adult HIV-HCV coinfected patients.

The role of exposure to antiretrovirals (ARV) and serum matrix metalloproteases (MMPs) on liver fibrosis (LF) progression in human immunodeficiency virus (HIV) mono or HIV- hepatitis C virus (HCV) coinfection is unclear. Thus, 213 Caucasian adult HIV-infected patients were studied, 111 of whom had HCV-coinfection and 68 were HCV-monoinfected. Patients with ethanol consumption >50 g/day, hepatitis B coinfection, non-infective liver diseases or HAART adherence <75% were excluded. LF was assessed by transient elastometry (TE, Fibroscan). Serum levels of MMPs (MMP -1,-2,-3,-8,-9,-10 and -13) and their tissue inhibitors (TIMP-1,-2 and -4) were measured by ELISA microarrays. Associations with LF were statistically analysed. Protease inhibitors, usually administered to patients with advanced LF were excluded from the analysis. Increased LF was significantly associated with d4T (P = 0.006) and didanosine (ddI) use (P = 0.007), months on d4T (P = 0.001) and on ARV (P = 0.025), duration of HIV (P < 0.0001) and HCV infections (P < 0.0001), higher HIV (P = 0.03) and HCV loads (P < 0.0001), presence of lipodystrophy (P = 0.02), male gender (P = 0.02), older age (P = 0.04), low nadir (P = 0.02) and current CD4(+) T-cells (P < 0.0001), low gain of CD4(+) T-cells after HAART (P = 0.01) and higher MMP-2 (P = 0.02) and TIMP-2 serum levels (P = 0.02). By logistic regression the only variables significantly associated with increased LF were: use of ddI (OR 8.77, 95% CI: 2.36-32.26; P = 0.005), male gender (OR 7.75, 95% CI: 2.33-25.64, P = 0.0008), HCV viral load (in log) (OR 3.53, 95% CI: 2.16-5.77; P < 0.0001) and age (in years) (OR 1.21, 95% CI: 1.09-1.34, P = 0.0003). We conclude that only higher HCV viral load, older age, male gender, and use of ddI associated independently with increased LF in our study.

The role of nucleoside reverse transcriptase inhibitors usage in the incidence of hyperlactatemia and lactic acidosis in HIV/AIDS patients.

Hyperlactatemia and lactic acidosis (LA) are among the most dangerous and life-threatening side effect that occurs during therapy with some nucleoside reverse transcriptase inhibitors (NRTIs), mainly didanosine (ddI) and stavudine (d4T), also known as d-drugs. Therefore, we performed a prospective, follow-up study and aimed to examine the incidence rates (IR) and rate ratios (RR) of hyperlactatemia and LA for each NRTI. Three hundred and ninety-six HIV-patients were included in final analysis comprising 783.8 person-years of follow-up. Between 1st January 2000 and 1st January 2008, 19 cases of hyperlactatemia and 15 cases of LA were recorded. Between regimens with the significant impact for developing hyperlactatemia and LA the lowest IR was for didanosine (IR=2.87 per 100 person-years, 95%CI=0.45-9.25 and IR=4.31 per 100 person-years, 95%CI=1.07-13.91, respectively), and the highest for didanosine+stavudine (IR=10.17 per 100 person-years, 95%CI=1.02-19.76 and IR=7.39 per 100 person-years, 95%CI=1.02-13.05, respectively). Compared to didanosine alone the RR of hyperlactatemia was 2.67 (95%CI=1.11-12.52) for stavudine, and 4.06 (95%CI=1.31-15.48) for didanosine+stavudine. The RR of LA was 3.12 (95%CI=1.13-10.65) for stavudine, and 5.13 (95%CI=1.54-13.37) for didanosine+stavudine in comparison with didanosine alone. Other risk factors for AP were CD4 cell count less than 200 cells/mm³ and female sex. Our results suggest that the use of stavudine alone or in combination with didanosine should not be used as first-line therapy, especially in patients with CD4 cell count less than 200 cells/mm³ and females if other treatment options are available.

The combined use of known antiviral reverse transcriptase inhibitors AZT and DDI induce anticancer effects at low concentrations.

A hallmark of tumor cell survival is the maintenance of elongated telomeres. It is known that antiviral reverse transcriptase inhibitors (RTIs) such as azidothymidine (AZT) and didanosine (ddI) lead to telomere shortening at high, potentially toxic concentrations. We hypothesized that those drugs might have synergistic effects enabling successful therapy with low, nontoxic concentrations. Biologic effects of AZT and ddI were analyzed at concentrations that correspond to minimal plasma levels achieved during human immunodeficiency virus therapy. Long-term coapplication of low-dose AZT and ddI induced a significant shortening of telomeres in the tumor cell lines HCT-116, SkMel-28, MelJuso, and Jurkat. Treatment of cells with both RTI, but not with single RTI, led to a significant accumulation of γH2AX, to p53 phosphorylation, and to cell apoptosis in all cell lines. Oral low-dose dual RTI application but not low-dose single RTI application was associated with a significantly reduced tumor growth of HCT-116 cells in mice. This antiproliferative activity of the combined use of AZT and ddI at low, clinically applicable concentrations warrants clinical testing in human solid cancer.

Noncirrhotic portal hypertension associated with didanosine: a case report and literature review.

Noncirrhotic portal hypertension (NCPH) has recently been reported as a liver complication in human immunodeficiency virus (HIV)-infected patients and has been found to be associated with exposure to didanosine. Here, we describe the case of an HIV-infected patient with portal hypertension who initially presented with massive ascites and portal vein thrombosis. The patient's HIV-1 infection was well-controlled with highly active antiretroviral therapy (lamivudine/didanosine plus nevirapine) for 3 years since its diagnosis in 2007. He had no history of alcoholism, drug abuse, or liver diseases. An extensive work-up for other possible causes of liver disease was performed, but the results were inconclusive. In addition to reporting this case, we have reviewed the literature on didanosine-related NCPH and analyzed the findings of 61 similar previously reported cases.

Ten-year diabetes incidence in 1046 HIV-infected patients started on a combination antiretroviral treatment.

OBJECTIVE: To evaluate the incidence and determinants of diabetes in a cohort of HIV-infected adults initiated with combination antiretroviral treatment (cART) in 1997-1999 and followed up to 2009. DESIGN: Prospective study of 1046 patients at 47 French clinical sites. METHODS: Potential determinants of diabetes occurrence, defined by confirmed increased glycemia and/or initiation of antidiabetic treatment, were assessed by a proportional hazards model, including time-updated metabolic parameters and ART exposure. RESULTS: Among the cohort, representing 7846 person-years of follow-up (PYFU), 54% received indinavir, 75% stavudine and 52% didanosine. Overall, 111 patients developed diabetes, with an incidence of 14.1/1000 PYFU (14.6 in men, 12.6 in women). Incidence peaked in 1999-2000 (23.2/1000 PYFU) and decreased thereafter. The incidence of diabetes was associated [adjusted hazard ratio (aHR), all P<0.02] with older age (hazard ratio = 2.13 when 40-49 years, hazard ratio = 3.63 when ≥50 years), overweight (hazard ratio = 1.91 for a BMI 25-29 kg/m(2), hazard ratio = 2.85 >30 kg/m(2)), waist-to-hip ratio (hazard ratio = 3.87 for ≥0.97 male/0.92 female), time-updated lipoatrophy (hazard ratio = 2.14) and short-term exposure to indinavir (0-1 year: hazard ratio = 2.53), stavudine (0-1 year: hazard ratio = 2.56, 1-2 years: hazard ratio = 2.65) or didanosine (2-3 years: hazard ratio = 3.16). Occurrence of diabetes was not associated with HIV-related markers, hepatitis C, hypertension or family history of diabetes. Insulin resistance was predictive for incident diabetes. CONCLUSIONS: In this nationwide cohort, followed for 10 years after cART initiation, diabetes incidence peaked in 1990-2000, was markedly higher than that reported for European uninfected or other HIV-infected populations (4-6/1000 PYFU) and linked with age and adiposity. Adiposity and glycemic markers should be monitored in aging HIV-infected patients.

The use of hot and cold high pressure homogenization to enhance the loading capacity and encapsulation efficiency of nanostructured lipid carriers for the hydrophilic antiretroviral drug, didanosine for potential administration to paediatric patients.

A major obstacle to the application of nanostructured lipid carriers (NLCs) as carriers for hydrophilic drugs is the limited loading capacity (LC) and encapsulation efficiency (EE) of NLCs for these molecules. The purpose of this research was to design and implement a strategy to enhance the LC and EE of NLCs for the hydrophilic drug, didanosine (DDI). DDI was dispersed in Transcutol(®) HP and the particle size of DDI in the liquid lipid was reduced gradually using hot high pressure homogenization (HPH). The product obtained thereafter was added to Precirol(®) ATO 5 and the hot mixture was immediately dried using liquid nitrogen. The dried materials were then ground and passed through a 200 µm sieve and the solid lipid particles were dispersed in a surfactant solution and subsequently used to manufacture DDI-loaded NLCs using cold HPH. The LC and EE of NLCs for DDI manufactured using the new strategy were 3.39 ± 0.63% and 51.58 ± 1.31%, respectively, compared to 0.079 ± 0.001% and 32.45 ± 0.08%, respectively, obtained when DDI-loaded NLCs were produced using conventional hot HPH. The enhanced LC and EE for DDI make NLCs a potential technology for the oral administration of DDI to paediatric patients.

Squalenoylation: a generic platform for nanoparticular drug delivery.

Squalene is a triterpene widely distributed in nature that is an intermediate in the cholesterol biosynthesis pathway. The remarkable dynamic folded conformation of squalene has been used to chemically conjugate this lipid with various therapeutic molecules to construct nanoassemblies of 100-300 nm. In this review, we discuss the new concept of "squalenoylation" through application to anticancer (i.e. gemcitabine, paclitaxel, cisplatin etc.…) or antiviral (ddI, ddC) compounds. In a lego-type approach, it is also possible to construct multifunctional nanoparticles endowed with additional imaging functionalities (i.e. "Nanotheragnostics"). This new nanotechnology platform is expected to have important applications in pharmacology.