Pompeyo Viciana

Pharmacokinetic Interactions Between Efavirenz and Rifampicin in HIV-Infected Patients with Tuberculosis

ObjectiveTo evaluate the pharmacokinetic interactions between efavirenz and rifampicin (rifampin) in patients with HIV infection and tuberculosis.DesignNonblind, randomised, pharmacokinetic study.Patients24 patients (21 male, 3 female; mean age 37 years) with HIV infection and tuberculosis.InterventionsPatients were randomised to one of the following treatments: group A (n = 16) received antituberculosis drugs without rifampicin, plus highly active antiretroviral therapy (HAART) including efavirenz 600mg once daily, on days 1 to 7. Patients were then switched to rifampicin in bodyweight-adjusted fixed-dose combination plus HAART including efavirenz 600mg once daily (group A-1; n = 8) or efavirenz 800mg once daily (group A-2; n = 8). Group B (n = 8) received rifampicin in bodyweight-adjusted fixed-dose combination on days 1 to 7; on day 8, HAART including efavirenz 800mg once daily was added. Blood samples were obtained on days 7 and 14.MethodsPlasma concentrations of efavirenz and rifampicin were quantified by using validated high performance liquid chromatography assays, and pharmacokinetic parameter values were determined by noncompartmental methods. The differences between pharmacokinetic parameters on days 7 and 14 were used to assess interactions.ResultsThere was a correlation between the pharmacokinetic parameters of efavirenz and the dose/kg administered. For efavirenz, mean (median) peak concentration, trough concentration and area under the concentration-time curve over the administration interval decreased 24% (24%), 25% (18%) and 22% (10%), respectively, in the presence of rifampicin. Large interpatient variability was observed, suggesting that plasma concentration monitoring of efavirenz may be advisable. Overall, the pharmacokinetics of efavirenz 800mg plus rifampicin were similar to those of efavirenz 600mg without rifampicin. The pharmacokinetics of rifampicin did not change substantially in the presence of efavirenz. Differences in patients’ bodyweight appeared to cause further differences in exposure to efavirenz. Plasma concentrations of efavirenz in patients weighing <50kg were similar to those previously described in HIV-infected patients without concomitant tuberculosis. However, plasma concentrations in patients weighing >50kg were almost halved compared with those in patients weighing <50kg.ConclusionsAlthough the minimal effective efavirenz plasma concentration that assures virological success is not currently known, it may be advisable to increase the dosage of efavirenz to 800mg once daily when it is coadministered with rifampicin. Rifampicin can be used with efavirenz without dosage modification.

The Use of Transient Elastometry for Assessing Liver Fibrosis in Patients with HIV and Hepatitis C Virus Coinfection

BACKGROUND Transient elastometry (TE) is accurate for detecting significant liver fibrosis and cirrhosis in hepatitis C virus (HCV)-monoinfected patients. However, this procedure has been insufficiently validated in patients with human immunodeficiency virus (HIV) and HCV coinfection. The purpose of this study was to validate reported cutoff values of TE that discriminate significant liver fibrosis and cirrhosis in HIV-HCV-coinfected subjects. METHODS Liver stiffness measurements were obtained for 169 HIV-HCV-coinfected adult patients who had undergone a liver biopsy or who had received a nonhistologic diagnosis of cirrhosis within 12 months before or after a liver stiffness measurement. Patients had received no prior therapy for HCV infection. RESULTS TE measurements ranged from 3.6 kPa to 75 kPa. The area under the receiver operating characteristic curve was 0.87 (95% confidence interval, 0.84-0.93) for significant liver fibrosis and 0.95 (95% confidence interval, 0.92-0.99) for cirrhosis. To diagnose significant liver fibrosis, a cutoff value of 7.2 kPa was associated with a positive predictive value of 88% and a negative predictive value of 75%. Thirty-four patients (20%) were misclassified when this cutoff value was used. Thirteen (24%) of 54 patients with liver stiffness values <7.2 kPa had significant liver fibrosis detected by liver biopsy. To diagnose cirrhosis, a cutoff value of 14.6 kPa was associated with a positive predictive value of 86% and a negative predictive value of 94%. Thus, 13 patients (10%) had disease that was misclassified using this cutoff value. CONCLUSIONS We found that the diagnostic accuracy of TE was high for detecting cirrhosis and good for diagnosis of significant liver fibrosis. However, the performance of TE was low for discriminating mild fibrosis from significant liver fibrosis, which might limit the applicability of this technique in clinical practice.

Unexpected CD4 cell count decline in patients receiving didanosine and tenofovir-based regimens despite undetectable viral load.

Background: We recently observed a significant CD4 cell count decline in patients receiving didanosine (ddI) 400 mg, tenofovir (TDF) and nevirapine (NVP), despite virological suppression. Methods: We identified from our computerized patient database subjects who initiated combinations containing ddI and/or TDF for reasons other than virological failure, including simplification or intolerance. Changes in total, CD4+ and CD8+ lymphocyte counts since the initiation of therapy were analysed retrospectively. Plasma concentration of ddI was prospectively determined in eight of these patients receiving ddI 400 mg + TDF + NVP and 3 weeks after a ddI dosage reduction. Results: A total of 302 patients were studied. A significant decrease in CD4 and CD8 and in total lymphocyte counts was only seen in subjects receiving ddI standard dose + TDF-containing regimens, despite the maintenance of viral suppression. More than 50% of these patients showed a decline of more than 100 CD4 cells at 48 weeks. In contrast, subjects not receiving ddI + TDF together experienced the expected progressive increase in CD4 T-cell counts. Plasma levels of ddI were elevated in all patients receiving the standard ddI dose + TDF. DdI plasma levels significantly decreased when patients weighting > 60 kg reduced ddI dose to 250 mg, achieving similar levels to those generated by ddI 400 mg without TDF. Conclusions: Co-administration of ddI at standard doses plus TDF appears to exert a deleterious effect on CD4 and CD8 counts. Although lymphocyte toxicity related to excessive ddI plasma levels could explain our findings, other mechanisms cannot be excluded. Pharmacokinetic data suggest ddI dose reduction when coadministered with TDF.

Delayed diagnosis of HIV infection in a multicenter cohort: prevalence, risk factors, response to HAART and impact on mortality.

To study the prevalence of Delayed HIV Diagnosis (DHD) and its associated risk factors, to evaluate the effect of DHD on virological and immunological responses to HAART and to estimate the impact of DHD on all-causes mortality. Prospective cohort of 2, 564 HIV-positive HAART-naïve subjects attending 19 hospitals in Spain, 2004-2006. Estimations were made by logistic regression and survival analyses by Cox regression models. Prevalence of DHD was 37.3% (35.0-39.6). DHD was related to low educational level (OR:1.31, 95% CI:1.0-1.7). Compared to men who have sex with men (MSM), DHD was more frequent in heterosexuals (OR:1.9 95% CI:1.5-2.5) and injection drug users (IDUs) (OR:2.0 95% CI:1.5-2.8). An interaction between age and sex was found. Although risk of having DHD did not increase after age 30 in women, it increased linearly with age in men. No differences in virological (OR 1.2 95% CI: 0.8-1.8) and CD4 T cell (OR 1.1 95% CI: 0.7-1.8) responses to HAART were seen. The adjusted hazard ratio for death in patients with DHD was 5.2, (95% CI: 1.9-14.5). DHD is very common, especially in older men, heterosexuals and IDUs. Although we did not find differences in virological and immunological responses to HAART, we did observe higher mortality in people with DHD. Increased efforts to early diagnose HIV infection are urgently needed.

Q fever: epidemiology, clinical features and prognosis. A study from 1983 to 1999 in the South of Spain.

OBJECTIVES Clinical polymorphism is a main feature of Q fever and, depending upon the geographic location, differences in its clinical picture have been described. The objective of this study was to determine the epidemiology, clinical features and prognosis of acute Q fever in our area. METHODS From 1985 to 1999, consecutive cases of Q fever, presented as febrile syndrome and attended in a tertiary teaching hospital in Sevilla, Spain, were included and followed prospectively. RESULTS Two hundred and thirty-one cases of acute Q fever were included. A non-focalized febrile syndrome lasting from 7 to 28 days (fever of intermediate duration) was the most frequent presentation (n=208, 90%). One hundred and forty-eight patients had hepatitis. Overall, 53% of the cases were urban and contact with animals was referred in 39% of the patients. No relationship between clinical presentation and possible route of infection was observed. Prognosis was excellent (100% cured), although in 18 patients fever was prolonged more than 28 days and three patients developed life-threatening organ affection. Antimicrobial treatment was more effective if it was administered in the first two weeks (median defervescence of fever: 3 days versus 5.5 days, p<0.01). CONCLUSIONS Acute Q fever is a common cause of fever of intermediate duration, even in urban areas. Elevation of hepatic enzymes was the most frequent laboratory finding. Severe organ affection is uncommon and the overall prognosis of the disease is excellent. Early treatment seems to shorten the duration of the disease.

Efficacy of pegylated interferon plus ribavirin treatment in HIV/hepatitis C virus co-infected patients receiving abacavir plus lamivudine or tenofovir plus either lamivudine or emtricitabine as nucleoside analogue backbone

OBJECTIVES To compare the response to hepatitis C virus (HCV) therapy among human immunodeficiency virus (HIV)/HCV co-infected patients receiving a nucleos(t)ide reverse transcriptase inhibitor [N(t)RTI] backbone consisting of abacavir plus lamivudine with that observed in subjects who receive tenofovir plus lamivudine or emtricitabine. METHODS A total of 256 subjects, enrolled in a cohort of 948 HIV-infected patients who received pegylated interferon and ribavirin from October 2001 to January 2006, were included in this study. All patients were taking one protease inhibitor or one non-nucleoside reverse transcriptase inhibitor and abacavir plus lamivudine or tenofovir plus lamivudine or emtricitabine as N(t)RTI backbone during HCV therapy. Sustained virological response (SVR) rates in both backbone groups were compared. RESULTS In an intention-to-treat analysis, 20 out of 70 (29%) individuals under abacavir and 83 out of 186 (45%) under tenofovir showed SVR (P = 0.02). N(t)RTI backbone containing tenofovir was an independent predictor of SVR in the multivariate analysis [adjusted odds ratio (95% CI), 2.6 (1.05-6.9); P = 0.03]. The association between abacavir use and lower SVR was chiefly seen in patients with plasma HCV-RNA load higher than 600 000 IU/mL and genotype 1 or 4. Among patients treated with ribavirin dose <13.2 mg/kg/day, 3 (20%) of those under abacavir versus 22 (52%) under tenofovir reached SVR (P = 0.03), whereas the rates were 31% and 38% (P = 0.4), respectively, in those receiving >/=13.2 mg/kg/day. CONCLUSIONS HIV-infected patients who receive abacavir plus lamivudine respond worse to pegylated interferon plus ribavirin than those who are given tenofovir plus lamivudine or emtricitabine as N(t)RTI backbone, especially in those receiving lower ribavirin doses.

Patients' characteristics and clinical implications of suboptimal CD4 T-cell gains after 1 year of successful antiretroviral therapy.

To describe characteristics and prognosis of patients with suboptimal immunological response to combined antiretroviral therapy (CART). Using data from a multicenter cohort study, we selected patients who initiated CART and showed suboptimal CD4-T cell response (defined as <50 cells/L increase) after 1 year of therapy, despite sustained virological suppression. Characteristics of those patients were compared with subjects who showed optimal immunological response. Of 650 patients with virological suppression, 108 (16.6%) showed suboptimal CD4-T cell response. Independent predictors of suboptimal response were previous injection drug use (OR, 1.85; 95% CI, 1.12-2.98) and age at CART initiation (OR, 1.04 per year increase; 95%CI, 1.01-1.06). Hepatitis C virus coinfection was not associated with impaired immunological response. As compared with patients with optimal immunological response, those with suboptimal response had a higher mortality rate (3.22 versus 0.71 per 100 person-years; p=.001), but a similar rate of new AIDS-defining events. In patients with sustained virological suppression with CART, previous injection drug use, but not hepatitis C virus coinfection, and older age at initiation of therapy were associated with suboptimal CD4 T-cell responses. Patients with suboptimal response had a higher mortality over time, mainly due to diseases other than AIDS-defining events.

Recomendaciones de GESIDA/Plan Nacional sobre el Sida respecto al tratamiento antirretroviral en pacientes adultos infectados por el virus de la inmunodeficiencia humana en el año 2002

Objetivo Efectuar una puesta al dia de las recomendaciones sobre el tratamiento antirretroviral (TAR) para los adultos infectados por el virus de la inmunodeficiencia humana (VIH). Metodos Estas recomendaciones se han consensuado por un comite del Grupo de Estudio de Sida (GESIDA) y del Plan Nacional sobre el Sida (PNS). Para ello, se han revisado los avances en la fisiopatologia del VIH, los resultados de eficacia y seguridad de ensayos clinicos, estudios de cohortes y de farmacocinetica, publicados en revistas biomedicas o presentados en congresos en los ultimos anos. Se han definido tres niveles de evidencia segun la procedencia de los datos: estudios aleatorizados (nivel A), de cohortes o de caso-control (nivel B) u opinion de expertos (nivel C). En cada una de las situaciones se ha establecido recomendar, considerar o no recomendar el TAR. Resultados En el momento actual, el TAR con combinaciones de al menos 3 farmacos constituye el tratamiento de eleccion de la infeccion cronica por el VIH. En los pacientes con una infeccion por VIH sintomatica se recomienda iniciar el TAR. En los pacientes asintomaticos el inicio de TAR se basara en la cifra de linfocitos CD4+/μl y en la carga viral plasmatica (CVP): a) en pacientes con linfocitos CD4+ 350 cel./μl se puede diferir el inicio del TAR. El objetivo del TAR es lograr una CVP indetectable. La adherencia al TAR tiene un papel en la durabilidad de la respuesta antiviral. Las opciones terapeuticas en los fracasos del TAR son limitadas por la aparicion de resistencias cruzadas. Los estudios genotipicos en estos casos son de utilidad. La toxicidad es un factor limitante del TAR. Tambien se discuten los criterios de TAR de la infeccion aguda, embarazo y profilaxis postexposicion, y el manejo de la coinfeccion por el VIH y los virus de las hepatitis B y C (VHC y VHB). Conclusiones En la actualidad existe una actitud mas conservadora para iniciar el TAR que en recomendaciones previas. La cifra de linfocitos CD4+ es el factor de referencia mas importante para iniciar el TAR en pacientes asintomaticos. Por otra parte, el numero considerable de farmacos disponibles, los metodos de monitorizacion mas sensibles (CVP) y la posibilidad de determinar las resistencias hacen que las estrategias terapeuticas sean mucho mas individualizadas.

Clinical Outcome of HIV-Infected Patients with Sustained Virologic Response to Antiretroviral Therapy: Long-Term Follow-Up of a Multicenter Cohort

Background Limited information exists on long-term prognosis of patients with sustained virologic response to antiretroviral therapy. We aimed to assess predictors of unfavorable clinical outcome in patients who maintain viral suppression with HAART. Methods Using data collected from ten clinic-based cohorts in Spain, we selected all antiretroviral-naive adults who initiated HAART and maintained plasma HIV-1 RNA levels <500 copies/mL throughout follow-up. Factors associated with disease progression were determined by Cox proportional-hazards models. Results Of 2,613 patients who started HAART, 757 fulfilled the inclusion criteria. 61% of them initiated a protease inhibitor-based HAART regimen, 29.7% a nonnucleoside reverse-transcriptase inhibitor-based regimen, and 7.8% a triple-nucleoside regimen. During 2,556 person-years of follow-up, 22 (2.9%) patients died (mortality rate 0.86 per 100 person-years), and 40 (5.3%) died or developed a new AIDS-defining event. The most common causes of death were neoplasias and liver failure. Mortality was independently associated with a CD4-T cell response <50 cells/L after 12 months of HAART (adjusted hazard ratio [AHR], 4.26 [95% confidence interval {CI}, 1.68–10.83]; P = .002), and age at initiation of HAART (AHR, 1.06 per year; 95% CI, 1.02–1.09; P = .001). Initial antiretroviral regimen chosen was not associated with different risk of clinical progression. Conclusions Patients with sustained virologic response on HAART have a low mortality rate over time. Long-term outcome of these patients is driven by immunologic response at the end of the first year of therapy and age at the time of HAART initiation, but not by the initial antiretroviral regimen selected.

Hepatitis C virus and human immunodeficiency virus coinfection in Spain

OBJECTIVE AND METHODS In a cross-sectional study, based on a cohort composed of HIV-infected patients of fifteen tertiary level institutions of Spain, the main data of the entire cohort are described, characteristics of patients with or without hepatitis C coinfection are compared, and the possible association of hepatitis C virus coinfection with socioeconomic, HIV-related, and hepatitis B-related variables is assessed. RESULTS A total of 4,709 patients are studied. Median of age is 37 years, 78.3% are male. HIV risk behaviours are: parenteral drug use in 63.8% of patients, heterosexual in 22.3%, and homosexual in 10.8%. Serology of hepatitis C is positive in 69.2% of participants. The following variables are associated with increased prevalence of hepatitis C coinfection, both in univariate and in multivariate analysis: HIV risk behaviour, positive anti-HBs, longer time elapsed since HIV infection diagnosis, younger age, lower social status, lower CD4 cell count increase between nadir and last available result, and lower educational level (all P<0.001). Patients with heterosexual behaviour are more frequently coinfected than patients with homosexual behaviour (P<0.001). CONCLUSION This study highlights that, in Spain, more than two thirds of patients with HIV infection are coinfected with hepatitis C virus.