1 Enfermedades Infecciosas, Hospital Ramón y Cajal, Carretera de Colmenar, km 9.100, 28034-Madrid; 2 Laboratorios Dr Esteve, Barcelona; 3 Hospital Virgen de la Victoria, Málaga; 4 Hospital General, Alicante; 5 Hospital Virgen del Rocío, Sevilla; 6 Fundación Jiménez-Díaz, Madrid; 7 Hospital La Paz, Madrid; 8 Hospital Son Dureta, Palma de Mallorca; 9 Hospital Carlos III, Madrid; 10 Centro Nacional Microbiología, Majadahonda, Spain
Received 12 September 2002; returned 7 March 2003; revised 26 September 2003; accepted 17 November 2003
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Abstract |
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Methods: This was a multicentre, open-label (with blinded centralized randomization), parallel, no-treatment, controlled clinical trial. HIV-infected patients, with at least one previous treated episode of VL and with negative bone marrow aspirate for Leishmania parasites prior to the study, were randomized to receive either ABLC 3 mg/kg/day every 21 days (ABLC) or no treatment (NT). Patients were followed-up every 9 weeks for up to 12 months, and the efficacy was measured as the proportion of patients remaining free (non-relapse) of VL at 1 year of follow-up. The primary analysis was performed on an intention-to-treat basis.
Results: One hundred and fifteen patients were screened, but only 17 were randomized: eight in the ABLC group and nine in the NT group. The intention-to-treat analysis of data showed 50% of patients remaining free of VL at 12 months of follow-up (95% CI = 15.7%, 84.3%) in the ABLC group, and 22.2% (95% CI = 2.8%, 60.0%) in the NT group. The non-relapse odds ratio was 3.5 (95% CI = 0.30%, 52.0%) favouring ABLC. ABLC was well tolerated: patients only presented infusion-related mild adverse events. No patients from either group discontinued treatment or died during follow-up.
Conclusions: ABLC, administered every 21 days for 12 months, is useful as secondary prophylaxis in preventing VL relapse in HIV-infected patients, and is well tolerated.
Keywords: leishmaniasis, HIV, amphotericin B, clinical trial with blinded centralized randomization
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Introduction |
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The value of secondary prophylaxis against leishmaniasis in HIV-infected patients in the HAART era is controversial. To date, no prospective randomized clinical trial has been performed to clarify this point. New lipid formulations of AmB are less toxic than non-lipid formulations2 and have shown good anti-leishmanial efficacy in experimental models and in immunocompetent patients.3 The pharmacokinetic properties of AmB lipid formulations allow high tissue levels of AmB to be realized in bone marrow, liver, spleen and lung, thus enabling the reservoir of these infectionsmainly localized in these organsto be treated.
The present study was designed to investigate the efficacy and safety of amphotericin B lipid complex (ABLC) in the secondary prophylaxis of VL in HIV-infected patients.
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Materials and methods |
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Study population
During September 1997December 1999, 115 HIV-infected patients with at least one previous episode of visceral leishmaniasis (parasitologically confirmed) were screened. Inclusion criteria: subjects of either gender, aged 18 years or older, with HIV diagnosis confirmed by Western blot and a negative parasitic culture from bone marrow aspirate. Exclusion criteria: presence of aminotransferase levels 10 times the upper normal limit, cardiomyopathy or heart failure, creatinine levels twice the upper normal limit, allergy to AmB or ABLC, life expectancy <12 months, or other concomitant VL treatment. Women of childbearing age were excluded if they wereor might becomepregnant, or were lactating.
Study design
A multicentre, open-label (with blinded centralized randomization), parallel trial was conducted to compare ABLC with no treatment for the secondary prophylaxis of VL in HIV-infected patients.
Randomization and treatments
A randomization list was prepared using the SAS program. The randomization process was blinded and centralized: once the eligibility of a patient was established, the investigators informed the study headquarters. The patient was then registered in the study and the investigator instructed on which treatment to assign: ABLC (Abelcet; The Liposome Company, Princeton, NJ, USA) 3 mg/kg/day intravenously, every 3 weeks (17 doses, administration performed by the investigator at the hospital) or no treatment. Randomization was stratified according to the number of previous VL episodes. The follow-up period was 51 weeks in both groups.
Assessments
Baseline evaluations were performed: confirmation of HIV diagnosis, and bone marrow aspirate; physical examination to assess the absence of VL-related signs and symptoms; electrocardiogram and laboratory tests (CD4 T lymphocyte and complete blood count, coagulation test and blood-chemistry panel). During the treatment period, the clinical evaluation and laboratory tests were repeated every 9 weeks and the electrocardiogram at the end of study. A bone marrow aspirate was repeated whenever the patient had clinical symptoms of VL, or at the end of the 1 year follow-up period.
Adverse events were assessed at each visit. The WHO scale for toxicity was used.
Efficacy was measured as the proportion of patients remaining free (non-relapse) of VL at 1 year of follow-up, defined as a negative resultof both smears and culture of bone marrow aspiratefor the presence of Leishmania parasites 4 weeks after the completion of therapy.
Parasitological test. Central laboratory
All tissue samples were analysed in a central laboratory: the WHO Collaborating Center on Leishmaniasis, Research Unit in Tropical Medicine and International Health, Majadahonda, Madrid, Spain. Demonstration of Leishmania amastigotes in the tissue samples was performed by means of smears of MayGrünwaldGiemsa stains, and examined at x1000 magnification. Tissue samples were cultured in NovyMcNeal Nicolle medium. The cultures were incubated at 25°C and considered negative if no flagellates were observed after 4 weeks. The microbiologists who evaluated tissue samples for absence of VL and relapse were blinded to the patients treatment.
Statistical analysis
This being a pilot study, no formal calculation of the required sample size was performed: 30 patients per group were initially considered sufficient to provide a reasonable estimate of treatment effect.
The proportions of patients remaining free of VL at 1 year were compared between treatment groups by means of the Fishers exact test, and their 95% CIs were estimated using binomial distribution. Odds ratios (OR) and their exact 95% CIs were calculated.
Safety analysis included all patients who had received at least one dose of ABLC. The rates of patients with adverse events were compared by means of the Fishers exact test.
Statistical analysis and data management were carried out by Laboratorios Dr Esteve, using Clintrial, SAS, StatXact and LogXact programs.
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Results |
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A total of 115 HIV-infected patients with at least one episode of visceral leishmaniasis were screened, but only 17 could be randomized in the study: eight patients to the ABLC group and nine patients to the NT group. Six patients had had one previous VL episode (three in the ABLC group and three in the NT group) and 11 patients had had two or more previous VL episodes (five in ABLC and six in NT). The baseline characteristics for the two treatments groups are shown in Table 1.
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The intention-to-treat analysis included all 17 randomized patients. Fifty percent of patients remained free of VL at the 1 year follow-up (95% CI = 15.7, 84.3) in the ABLC group and 22.2% (95% CI = 2.8, 60.0) in the NT group (one-sided P = 0.141). The non-relapse OR was 3.5 (95% CI = 0.30, 52.0) favouring ABLC.
The influence of the other prognostic factors (HIV stage, number of previous VL episodes, CD4 T cell count) was investigated using a logistic regression model including the treatment group. The adjusted non-relapse OR was 3.2 (95% CI = 0.24, 42.13) (one-sided P = 0.1895) favouring ABLC, thus showing that the other prognostic factors did not influence the results.
Safety and tolerability (Table 2)
ABLC mainly showed mild effects (shivering and/or fever) related to its administration, with a higher frequency than in the no-treatment group (P = 0.0032).
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Discussion |
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HIV-associated VL is characterized by its tendency to relapse, and most patients follow a multiple-relapse chronic course despite secondary prophylaxis. It is still unclear whether secondary prophylaxis against leishmaniasis is advisable in HIV-infected patients in the HAART era.4 Several approaches (non-randomized prospective studies) have been used, such as pentamidine every 34 weeks,2,5 liposomal AmB every 2 weeks,6 itraconazole7 and antimonials once a month.8 The pharmacokinetic characteristics of AmB entrapped in lipids has made ABLC a promising prophylactic agent for VL in HIV-infected patients, which is a population with a high incidence of VL relapse. This clinical trial was conducted based on this assumption.
Despite the high number of patients screened, only 17 could be randomized for a number of reasons: 43% had bone marrow samples positive for Leishmania; 36% of patients declined inclusion due to the possibility of being randomized to receive no treatment (many Spanish hospitals follow an empirical secondary prophylaxis protocol); fewer patients than hitherto were screened due to the low incidence of VL since the implementation of HAART.9
All patients included in this clinical trial were on HAART and most of them had a CD4 T cell count >200 cells/mm3 at inclusion, suggesting good restoration of immunity. The use of secondary life-long prophylaxis, such as that used for other opportunistic parasitic infections in AIDS patients, appears to be useful. The results obtained with ABLC are similar to those displayed in a retrospective study.7,9
The prognostic factors (HIV stage, number of previous VL episodes, CD4 T cell count) had no on important influence on the results, mainly due to the good balance obtained by randomization and blinded treatment assignment.
ABLC displayed a high rate of non-relapse at 12 months, with a low rate of adverse events (no patients died during the treatment period). Accordingly, ABLC is suggested to be a useful prophylaxis for VL/HIV co-infection. In order to support our proposal, however, more clinical trials are required on the efficacy of prophylaxis, and pharmacoeconomic studies are required.
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Acknowledgements |
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Members of the Spanish HIV-Leishmania Study Group, in alphabetic order: Dr Jordi Altés, Hospital Comarcal de lAlt Penedés (Barcelona); Dr Francisco Antunes, Hospital de Santa María (Lisboa, Portugal); Dr Elisabeth Buira, Hospital Clínic (Barcelona); Dr Almudena García, Hospital La Paz (Madrid); Dr Josep M. Gatell, Hospital Clínic (Barcelona); Dr Fuensanta Gavilán, Hospital Reina Sofía (Córdoba); Dr Jorge Marrero, Fundación Jiménez Díaz (Madrid); Dr Lola Prados, Hospital Virgen del Rocío (Sevilla); Dr Vicente Pintado, Hospital Ramón y Cajal (Madrid); Dr José Pérez-Molina, Hospital Gregorio Marañón (Madrid); Dr Federico Pulido, Hospital 12 de Octubre (Madrid); Dr Carmen Quereda, Hospital Ramón y Cajal (Madrid); Dr Antonio Rivero, Hospital Reina Sofía (Córdoba); Dr Víctor Roca, Hospital Clínico San Carlos (Madrid); Dr Rafael Rubio, Hospital 12 de Octubre (Madrid); Dr Jesús Santos, Hospital Virgen de la Victoria (Málaga); Dr Jesús Sanz, Hospital de La Princesa (Madrid); Dr Oscar Serrano, Hospital La Paz (Madrid); Dr Guillem Sirera, Hospital Germans Trías i Pujol (Barcelona); Dr Cecilia Tortajada, Hospital Clínic (Barcelona); Dr Julián Torre-Cisneros, Hospital Reina Sofía (Córdoba); Dr Eulalia Valencia, Hospital Carlos III (Madrid); Dr Elisa Vidal, Hospital Reina Sofía (Córdoba); Dr Carmen Chicharro, Instituto de Salud Carlos III, Majadahonda (Madrid); Mr Ismael Cruz, Instituto de Salud Carlos III, Majadahonda (Madrid); Mr Miguel A. Morales, Instituto de Salud Carlos III, Majadahonda (Madrid); Mrs Emilia García, Instituto de Salud Carlos III, Majadahonda (Madrid); Mrs Beatriz Gutierrez, Instituto de Salud Carlos III, Majadahonda (Madrid); Ms Soledad Casals, Laboratorios Dr Esteve (Barcelona); Dr Carmen García, Laboratorios Dr Esteve (Barcelona); Mr Artur Sans, Laboratorios Dr Esteve (Barcelona); Mr Alberto Puyada, Laboratorios Dr Esteve (Barcelona); Mr Ignasi Tolrà, Laboratorios Dr Esteve (Barcelona).
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Footnotes |
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Members of the Spanish HIV-Leishmania Study Group are listed in the Acknowledgements.
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References |
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