Sumonmal Uttayamakul

Effects of CYP2B6 G516T polymorphisms on plasma efavirenz and nevirapine levels when co-administered with rifampicin in HIV/TB co-infected Thai adults.

BackgroundCytochrome P450 2B6 (CYP2B6) metabolizes efavirenz and nevirapine, the major core antiretroviral drugs for HIV in Thailand. Rifampicin, a critical component of tuberculosis (TB) therapy is a potent inducer of CYP enzyme activity. Polymorphisms of CYP2B6 and CYP3A4 are associated with altered activity of hepatic enzyme in the liver and pharmacokinetics resulting in treatment efficacy. This study aimed to investigate whether CYP2B6 or CYP3A4 polymorphisms had effects on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults.ResultsWe studied 124 rifampicin recipients with concurrent HIV-1/TB coinfection, receiving efavirenz (600 mg/day) (n = 65) or nevirapine (400 mg/day) (n = 59) based antiretroviral therapy (ART). The frequencies of GG, GT and TT genotypes of CYP2B6-G516T were 38.46%, 47.69% and 13.85% in efavirenz group and 44.07%, 52.54% and 3.39% in nevirapine group, respectively. The mean 12-hour post-dose plasma efavirenz concentration in patients with TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (10.97 ± 2.32, 13.62 ± 4.21 and 8.48 ± 1.30 mg/L, respectively) were significantly higher than those with GT (3.43 ± 0.29, 3.35 ± 0.27 and 3.21 ± 0.22 mg/L, respectively) (p < 0.0001) or GG genotypes (2.88 ± 0.33, 2.45 ± 0.26 and 2.08 ± 0.16 mg/L, respectively) (p < 0.0001). Likewise, the mean 12-hour post-dose plasma nevirapine concentration in patients carrying TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (14.09 ± 9.49, 7.94 ± 2.76 and 9.44 ± 0.17 mg/L, respectively) tended to be higher than those carrying GT (5.65 ± 0.54, 5.58 ± 0.48 and 7.03 ± 0.64 mg/L, respectively) or GG genotypes (5.42 ± 0.48, 5.34 ± 0.50 and 6.43 ± 0.64 mg/L, respectively) (p = 0.003, p = 0.409 and p = 0.448, respectively). Compared with the effects of CYP2B6- 516TT genotype, we could observe only small effects of rifampicin on plasma efavirenz and nevirapine levels. After 12 weeks of both drug regimens, there was a trend towards higher percentage of patients with CYP2B6-TT genotype who achieved HIV-1 RNA levels <50 copies/mL compared to those with GT or GG genotypes. This is the first report to demonstrate the effects of CYP2B6 G516T polymorphisms on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults.ConclusionsCYP2B6-TT genotype had impact on plasma efavirenz and nevirapine concentrations, while rifampicin co-administration had only small effects.

Plasma nevirapine levels, adverse events and efficacy of antiretroviral therapy among HIV-infected patients concurrently receiving nevirapine-based antiretroviral therapy and fluconazole.

BackgroundThe clinical data of plasma NVP level, safety and efficacy of antiretroviral therapy (ART) for the concurrent use of nevirapine (NVP)-based ART and fluconazole (FLU) is scanty.MethodsA retrospective study was conducted in patients who were initiated NVP-based ART between October 2004 and November 2005. The objectives were to compare NVP levels, adverse events, and 36-week efficacy of NVP-based ART between patients who did not receive FLU (group A) and those who received FLU 200 mg/day or 400 mg/day (group B).ResultsThere were 122 patients with mean ± SD age of 36 ± 9 years; 81 in group A and 41 in group B. Median (IQR) baseline CD4 cell count was 29 (8–79) cell/mm3 in group A and 19 (8–33) cell/mm3 in group B (P = 0.102). Baseline characteristics between the two groups were similar. Mean ± SD NVP levels were 6.5 ± 3.0 mg/L in group A and 11.4 ± 6.1 mg/L in group B(P < 0.001). One (2.4%) patient in group B developed clinical hepatitis (P = 0.336). Six (7.4%) patients in group A developed NVP-related skin rashes (P = 0.096). There were no differences in term of 36-week antiviral efficacy between the two groups (P > 0.05).ConclusionCo-administration of NVP and daily dosage of FLU (200 mg/day and 400 mg/day) results in markedly increased trough plasma NVP level when compared to the administration of NVP alone. The concurrent use of NVP and FLU in very advanced HIV-infected patients is well-tolerated. The immunological and virological responses are favorable.

Body weight cutoff for daily dosage of efavirenz and 60-week efficacy of efavirenz-based regimen in human immunodeficiency virus and tuberculosis coinfected patients receiving rifampin.

ABSTRACT Seventy-one human immunodeficiency virus-infected patients with tuberculosis who were receiving a rifampin (rifampicin)-containing regimen were initiated on treatment with efavirenz at 600 mg/day plus stavudine-lamivudine. Fasting efavirenz concentrations at 12 h after dosing (C12) were monitored. The mean ± standard deviation efavirenz C12 at weeks 6 and 12 and after rifampin discontinuation were 4.5 ± 4.3, 3.8 ± 3.5, and 3.5 ± 2.7 mg/liter, respectively. High body weight was associated with a low efavirenz C12 at weeks 6 and 12 (P = 0.003, r = −0.255). The efavirenz C12 regression prediction line at 1 mg/liter intercepted a mean body weight of 57.5 kg.

Long-term seroprotective response of trivalent seasonal influenza vaccine in HIV-infected children, regardless of immunogenicity before immunisation.

Influenza vaccination can reduce disease in HIV-infected children. The durability of the antibody response after trivalent influenza vaccine is important for management. The aim of this prospective study was to assess the durability of seroprotection for trivalent influenza vaccine strains and the factors effecting seroprotective response regardless of immunogenicity before trivalent influenza vaccine at one and six months after immunisation. Hemagglutination inhibition assay was done at one and six months. Seventy-five HIV-infected children were enrolled after vaccination. Four children were lost to follow-up. None of the children had confirmed influenza infection between immunisation and hemagglutination inhibition at six months after influenza vaccination. Seventy-one children were included in the final analysis and immunogenicity of trivalent influenza vaccine strains at one and six months. Of these, 27 (38%) had complete seroprotection (Group A) and 44 (62%) had non-complete seroprotection (Group B). Sex, age and the body mass index of both groups were not different from each other (p > 0.05). There was a higher mean CD4 level and more children with RNA ≤40 copies/mL among Group A compared with Group B (p < 0.05). Other factors did not differ significantly. The durability of the seroprotective response after trivalent influenza vaccine was associated with a high CD4 level and virological suppression before vaccination.

Genome-Wide Association Study of HIV-Related Lipoatrophy in Thai Patients: Association of a DLGAP1 Polymorphism with Fat Loss

Abstract HIV-related lipoatrophy (LA) is a major adverse drug effect among HIV patients receiving the antiretroviral drug stavudine (d4T) in Southeast Asia. Although the development of LA could be observed in almost all HIV patients administered d4T for extended periods, there is considerable variation in the duration required to develop LA within this patient population. This study aimed to identify host genetic polymorphisms affecting the rate of LA onset in Thai HIV patients. We performed a genome-wide association study of HIV-related LA among patients at the Bamrasnaradura Infectious Diseases Institute, Thailand. Genotypes of HIV patients who developed LA within 2 years of treatment were compared with those of patients who did not develop LA after at least 4 years of treatment (non-LA patients). Genotypes of 49 LA and 92 non-LA patients at 578,525 single nucleotide polymorphisms (SNPs) were determined by Illumina bead arrays. The TaqMan real-time PCR method was used in a replication study. Five SNPs in the bead arrays, which showed the lowest p values in a comparison of LA with non-LA patients, were further tested in independent and sex-matched subpopulations consisting of 95 LA and 95 non-LA patients. This replication study revealed a significant association of LA with an SNP (rs12964965) in the gene encoding the Disks Large Homolog-Associated Protein 1 (DLGAP1), even after the correction for five multiple comparisons. These results strongly suggested involvement of the DLGAP1 gene product in the development of LA in Thai HIV patients.

The Effect of Detectable HIV Viral Load among HIV-Infected Children during Antiretroviral Treatment: A Cross-Sectional Study

The RNA viral load of human immunodeficiency virus (HIV) is initially used to determine the status of the HIV infection. The goal of therapy following treatment failure is to achieve and maintain virologic suppression. A detectable viral load may relate to the progression of HIV infection. A cross-sectional survey was conducted from January 2013 to December 2014 at the Bamrasnaradura Infectious Diseases Institute, Thailand. The aim was to determine the prevalence of detectable HIV viral load (dVL) and analyze the factors associated with post-dVL conditions that occur independently of a switch to a new antiretroviral agent. The prevalence of dVL was 27% (27 of 101). The mean ages of dVL and non-dVL children were 12.0 and 12.3 years, respectively. Age, sex, body mass index for age z-scores, previous tuberculosis disease history and parental tuberculosis history of both groups were not significantly different (p > 0.05). The prevalence of poor adherence (<95%), influenza-like illness (ILI) and opportunistic infections were higher in dVL than non-dVL children (p < 0.05). The mean nadir CD4 cell count during the study was lower in dVL than non-dVL children (646 compared to 867, respectively; p < 0.05). Other factors were not significant (all p > 0.05). In multivariable analysis, dVL was significantly associated with ILI (odds ratio (OR) = 9.6, 95% confidence interval (CI) = 1.3–69.4), adherence (OR = 0.195, 95% CI = 0.047–0.811) and nadir CD4 during the study (OR = 1.102, 95% CI = 1.100–1.305). The prevalence of dVL was 27% with this dVL among HIV-infected children found to be associated with ILI, poor adherence and lower nadir CD4 during the study.

Influenza A Virus Infection and Nucleotide Sequencing in HIV-Infected Children: A Case Report and Review of Literature

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