Effectiveness of Nifurtimox Eflornithine Combination Therapy (NECT) in T. b. gambiense second stage sleeping sickness patients in the Democratic Republic of Congo: Report from a field study

Background

Nifurtimox-eflornithine combination therapy (NECT) for the treatment of second stage gambiense human African trypanosomiasis (HAT) was added to the World Health Organization’s Essential Medicines List in 2009 after demonstration of its non-inferior efficacy compared to eflornithine therapy. A study of NECT use in the field showed acceptable safety and high efficacy until hospital discharge in a wide population, including children, pregnant and breastfeeding women, and patients with a HAT treatment history. We present here the effectiveness results after the 24-month follow-up visit.

Methodology/Principal findings

In a multicenter, open label, single arm phase IIIb study, second stage gambiense HAT patients were treated with NECT in the Democratic Republic of Congo. Clinical cure was defined 24 months after treatment as survival without clinical and/or parasitological signs of HAT. Of the 629 included patients, 619 (98.4%) were discharged alive after treatment and were examined for the presence of trypanosomes, white blood cell count in cerebro-spinal fluid, and disease symptoms. The clinical cure rate of 94.1% was comparable for all subpopulations analyzed at the 24-month follow-up visit. Self-reported adverse events during follow-up were few and concerned mainly nervous system disorders, infections, and gastro-intestinal disorders. Overall, 28 patients (4.3%) died during the course of the trial. The death of 16 of the 18 patients who died during the follow-up period was assessed as unlikely or not related to NECT. Within 24 months, eight patients (1.3%) relapsed and received rescue treatment. Sixteen patients were completely lost to follow-up.

Conclusions/Significance

NECT treatment administered under field conditions was effective and sufficiently well tolerated, no major concern arose for children or pregnant or breastfeeding women. Patients with a previous HAT treatment history had the same response as those who were naïve. In conclusion, NECT was confirmed as effective and appropriate for use in a broad population, including vulnerable subpopulations.

Trial registration

The trial is registered at ClinicalTrials.gov, number NCT00906880.

The advanced stage of the neglected tropical disease human African trypanosomiasis was, until relatively recently, treated with an old toxic arsenical drug and there was little investment in an improved treatment option. Eflornithine alone was efficacious, but difficult to administer as it required four two-hour infusions a day for 14 days. Nifurtimox-eflornithine combination therapy (NECT) was developed as a simplified and easier to use treatment and was shown to be effective and sufficiently well tolerated in a randomized clinical trial. The present study was conducted to assess the overall effectiveness, including the feasibility of implementation of NECT under field conditions in a wider population than in the randomized clinical trial. We found that NECT can be implemented under field conditions and in remote areas, with the necessary logistical support and staff training for treatment administration. Adverse events, although very frequent, were considered acceptable given the severity of the disease. Less than 10% of patients showed severe adverse events. Over 24 months, the case fatality rate was 4.5% and relapses were rare (1.3%). The effectiveness of NECT was confirmed in a broad spectrum of second stage gambiense HAT patients, including children, pregnant and breastfeeding women, and patients who had been previously treated for HAT.

Serological response to nifurtimox in adult patients with chronic Chagas disease: An observational comparative study in Argentina

Nifurtimox is indicated in Chagas disease but determining its effectiveness in chronic disease is hindered by the length of time needed to demonstrate negative serological conversion. We manually reviewed long-term follow-up data from hospital records of patients with chronic Chagas disease (N = 1,497) in Argentina diagnosed during 1967-1980. All patients were aged ≥18 years at diagnosis and were either treated with nifurtimox (n = 968) or received no antitrypanosomal treatment (n = 529). The primary endpoint was negative seroconversion (the "event"), defined as a change from positive to negative in the serological or parasitological laboratory test used at diagnosis. Time to event was from baseline visit to date of endpoint event or censoring. The effectiveness of nifurtimox versus no treatment was estimated with Cox proportional hazard regression using propensity scores with overlap weights to calculate the hazard ratio and 95% confidence interval. The nifurtimox group was younger than the untreated group (mean, 32.4 vs. 40.3 years), with proportionally fewer females (47.9% vs. 60.1%), and proportionally more of the nifurtimox group than the untreated group had clinical signs and symptoms of Chagas disease at diagnosis (28.9% vs. 14.0%). Median maximum daily dose of nifurtimox was 8.0 mg/kg/day (interquartile range [IQR]: 8.0-9.0) and median treatment duration was 44 days (IQR: 1-90). Median time to event was 2.1 years (IQR: 1.0-4.5) for nifurtimox-treated and 2.4 years (IQR: 1.0-4.2) for untreated patients. Accounting for potential confounders, the estimated hazard ratio (95% confidence interval) for negative seroconversion was 2.22 (1.61-3.07) favoring nifurtimox. Variable treatment regimens and follow-up duration, and an uncommonly high rate of spontaneous negative seroconversion, complicate interpretation of this epidemiological study, but with the longest follow-up and largest cohort analyzed to date it lends weight to the benefit of nifurtimox in adults with chronic Chagas disease. Trial registration: The study protocol was registered at ClinicalTrials.gov: NCT03784391.

Prescription of concomitant medications in patients treated with Nifurtimox Eflornithine Combination Therapy (NECT) for T.b. gambiense second stage sleeping sickness in the Democratic Republic of the Congo

BACKGROUND

Nifurtimox eflornithine combination therapy (NECT) to treat human African trypanosomiasis (HAT), commonly called sleeping sickness, was added to the World Health Organisation's (WHO) Essential Medicines List in 2009 and to the Paediatric List in 2012. NECT was further tested and documented in a phase IIIb clinical trial in the Democratic Republic of Congo (DRC) assessing the safety, effectiveness, and feasibility of implementation under field conditions (NECT-FIELD study). This trial brought a unique possibility to examine concomitant drug management.

METHODOLOGY/PRINCIPAL FINDINGS

This is a secondary analysis of the NECT-FIELD study where 629 second stage gambiense HAT patients were treated with NECT, including children and pregnant and breastfeeding women in six general reference hospitals located in two provinces. Concomitant drugs were prescribed by the local investigators as needed. Patients underwent daily evaluations, including vital signs, physical examination, and adverse event monitoring. Concomitant medication was documented from admission to discharge. Patients' clinical profiles on admission and safety profile during specific HAT treatment were similar to previously published reports. Prescribed concomitant medications administered during the hospitalization period, before, during, and immediately after NECT treatment, were mainly analgesics/antipyretics, anthelmintics, antimalarials, antiemetics, and sedatives. Use of antibiotics was reasonable and antibiotics were often prescribed to treat cellulitis and respiratory tract infections. Prevention and treatment of neurological conditions such as convulsions, loss of consciousness, and coma was used in approximately 5% of patients.

CONCLUSIONS/SIGNIFICANCE

The prescription of concomitant treatments was coherent with the clinical and safety profile of the patients. However, some prescription habits would need to be adapted in the future to the evolving available pharmacopoeia. A list of minimal essential medication that should be available at no cost to patients in treatment wards is proposed to help the different actors to plan, manage, and adequately fund drug supplies for advanced HAT infected patients.

TRIAL REGISTRATION NUMBER

The initial study was registered at ClinicalTrials.gov, number NCT00906880.

Detection of Trypanosoma cruzi by PCR in adults with chronic Chagas disease treated with nifurtimox

Chagas disease, a vector-borne parasitosis caused by Trypanosoma cruzi, is endemic to Latin America and has spread to other countries due to immigration of infected persons. It is estimated that 160,000 people are infected in Chile, most of them in the chronic phase and without etiological treatment. The infection is confirmed by conventional serological methods while molecular methods have become in valuable tools to evaluate parasitemia in treated and non-treated chronic Chagas disease patients. The objective of this study was to determine, by conventional Polymerase Chain Reaction, the presence of T. cruzi kinetoplastid DNA in peripheral blood samples from 114 adult individuals with confirmed chronic Chagas disease, before and 6.6 years (average) after treatment with nifurtimox. The samples were received and preserved in guanidine-EDTA until DNA purification. Conventional PCR assays were performed in triplicate with T. cruzi kinetoplastid DNA primers 121 and 122. The amplified products were fractionated by electrophoresis in 2% agarose gels. A 330 bp product represented a positive assay. 84.2% (96 cases) and 6.1% (7 cases) of the samples taken before and after the treatment, respectively, were positive. The McNemar test showed a statistically significant difference between the groups of samples (p<0.001). Since serological negativization (the current cure criterion) delay many years after therapy and positive parasitological results represent a treatment failure, the conversion of pre-therapy positive conventional PCR is a qualitative and complementary tool that could be included in protocols of prolonged follow-up.

Human African Trypanosomiasis in Emigrant Returning to China from Gabon, 2017

Human African trypanosomiasis is endemic to parts of sub-Saharan Africa and should be considered in the differential diagnosis of patients who have visited or lived in Africa. We report a 2017 case of stage 2 Trypanosoma brucei gambiense disease in an emigrant who returned to China from Gabon.

Mortality trends and risk factors in advanced stage-2 Human African Trypanosomiasis: A critical appraisal of 23 years of experience in the Democratic Republic of Congo

We conducted a retrospective study on mortality trends and risk factors in 781 naïve cases of advanced stage-2 sleeping sickness admitted between 1989 and 2012 at the National Reference Center for Human African Trypanosomiasis (HAT), Department of Neurology, Kinshasa University, Democratic Republic of Congo (DRC). Death was the outcome variable whereas age, gender, duration of disease, location of trypanosomes in body fluids, cytorachy, protidorachy, clinical status (assessed on a syndromic and functional basis) on admission, and treatment regimen were predictors in logistic regression models run at the 0.05 significance level. Death proportions were 17.2% in the standard melarsoprol schedule (3-series of intravenous melarsoprol on 3 successive days at 3.6 mg/kg/d, with a one-week interval between the series, ARS 9); 12.1% in the short schedule melarsoprol (10 consecutive days of intravenous melarsoprol at 2.2 mg/kg/d, ARS 10), 5.4% in the first-line eflornithine (14 days of eflornithine at 400 mg/kg/d in 4 infusions a day DFMO B), 9.1% in the NECT treatment regimen (eflornithine for 7 days at 400, mg/kg/d in 2 infusions a day combined with oral nifurtimox for 10 days at 15 mg/kg/d in 3 doses a day); and high (36%) in the group with select severely affected patients given eflornithine because of their clinical status on admission, at the time when this expensive drug was kept for treatment of relapses (14 days at 400 mg/kg/d in 4 infusions a day, DFMO A). After adjusting for treatment, death odds ratios were as follows: 10.40 [(95% CI: 6.55-16.51); p = .000] for clinical dysfunction (severely impaired clinical status) on admission, 2.14 [(95% CI: 1.35-3.39); p = .001] for high protidorachy, 1.99 [(95% CI: 1.18-3.37); p = .010] for the presence of parasites in the CSF and 1.70 [(95% CI: 1.03-2.81); p = .038] for high cytorachy. A multivariable analysis within treatment groups retained clinical status on admission (in ARS 9, ARS 10 and DFMO B groups) and high protidorachy (in ARS 10 and DFMO B groups) as significant predictors of death. The algorithm for initial clinical status assessment used in the present study may serve as the basis for further development of standardized assessment tools relevant to the clinical management of HAT and information exchange in epidemiological reports.

Safety Profile of Nifurtimox and Treatment Interruption for Chronic Chagas Disease in Colombian Adults

Nifurtimox (NFX) is one of the approved drugs used to treat Chagas disease. Safety profile studies and models on risk factors for treatment interruption in adults are scarce in Latin America. This study evaluated retrospectively the medical records of adult Chagas disease patients treated with NFX between 2007 and 2012 in Bogotá, Colombia. An accelerated failure time model was used, and associations were expressed as time ratio (TR). In total, 76 adult patients with NFX were included: 60 (79.0%) completed 60 days of treatment, 61 (80.3%) presented adverse drug reactions (ADRs), and 16 (21.0%) required treatment interruption. The predominant symptoms were epigastric pain (23.7%), nauseas (18.4%), sleep disturbances (18.4%), loss of appetite (17.1%), and temporary loss of memory (15.2%). ADRs were classified as mild (64.5%), moderate (30.4%), and severe (5.1%). Time of treatment was significantly longer when presenting ≤ 3 ADRs (TR: 1.78; 95% CI: 1.04–3.03), presence of non-severe ADRs (TR: 6.52; 95% CI: 3.24–13.1), doses of NFX ≤ 8 mg/kg/day (TR: 1.78; 95% CI: 0.90–3.49), and age < 48 years (TR: 1.57; 95% CI: 0.90–2.74). Treatment with NFX in adults caused a high frequency of ADRs, but most of the cases were mild and did not require treatment interruption. Severity and number of ADRs were the main predictors for treatment interruption.

Sensitivity analysis for causal inference under unmeasured confounding and measurement error problems

In this article, we present a sensitivity analysis for drawing inferences about parameters that are not estimable from observed data without additional assumptions. We present the methodology using two different examples: a causal parameter that is not identifiable due to violations of the randomization assumption, and a parameter that is not estimable in the nonparametric model due to measurement error. Existing methods for tackling these problems assume a parametric model for the type of violation to the identifiability assumption and require the development of new estimators and inference for every new model. The method we present can be used in conjunction with any existing asymptotically linear estimator of an observed data parameter that approximates the unidentifiable full data parameter and does not require the study of additional models.

In-hospital safety in field conditions of nifurtimox eflornithine combination therapy (NECT) for T. b. gambiense sleeping sickness

BACKGROUND

Trypanosoma brucei (T.b.) gambiense Human African trypanosomiasis (HAT; sleeping sickness) is a fatal disease. Until 2009, available treatments for 2(nd) stage HAT were complicated to use, expensive (eflornithine monotherapy), or toxic, and insufficiently effective in certain areas (melarsoprol). Recently, nifurtimox-eflornithine combination therapy (NECT) demonstrated good safety and efficacy in a randomised controlled trial (RCT) and was added to the World Health Organisation (WHO) essential medicines list (EML). Documentation of its safety profile in field conditions will support its wider use.

METHODOLOGY

In a multicentre, open label, single arm, phase IIIb study of the use of NECT for 2(nd) stage T.b. gambiense HAT, all patients admitted to the trial centres who fulfilled inclusion criteria were treated with NECT. The primary outcome was the proportion of patients discharged alive from hospital. Safety was further assessed based on treatment emergent adverse events (AEs) occurring during hospitalisation.

PRINCIPAL FINDINGS

629 patients were treated in six HAT treatment facilities in the Democratic Republic of the Congo (DRC), including 100 children under 12, 14 pregnant and 33 breastfeeding women. The proportion of patients discharged alive after treatment completion was 98.4% (619/629; 95%CI [97.1%; 99.1%]). Of the 10 patients who died during hospitalisation, 8 presented in a bad or very bad health condition at baseline; one death was assessed as unlikely related to treatment. No major or unexpected safety concerns arose in any patient group. Most common AEs were gastro-intestinal (61%), general (46%), nervous system (mostly central; 34%) and metabolic disorders (26%). The overall safety profile was similar to previously published findings.

CONCLUSIONS/SIGNIFICANCE

In field conditions and in a wider population, including children, NECT displayed a similar tolerability profile to that described in more stringent clinical trial conditions. The in-hospital safety was comparable to published results, and long term efficacy will be confirmed after 24 months follow-up.

REGISTRATION

The trial is registered at ClinicalTrials.gov, number NCT00906880.

[Nifurtimox, a bright future for treatment of Chagas disease]

Nifurtimox is one of the two molecules used for treatment of Chagas disease. Although posology has not yet been clearly defined, nifurtimox is increasingly used, especially in combination with eflonithin. Nifurtimox is perfectly suited to the WHO's Chagas disease eradication program.

Current and developing therapeutic agents in the treatment of Chagas disease

Chagas disease must be treated in all its stages: acute, indeterminate, chronic, and initial and middle determinant chronic, due to the fact that DNA of the parasite can be demonstrated by PCR in chronic cases, where optical microscopy does not detect parasites. Nifurtimox (NF) and benznidazole (BNZ) are the drugs accepted to treat humans based upon ethical considerations and efficiency. However, both the drugs produce secondary effects in 30% of the cases, and the treatment must be given for at least 30-60 days. Other useful drugs are itraconazole and posaconazole. The latter may be the drug to treat Chagas disease in the future when all the investigations related to it are finished. At present, there is no criterion of cure for chronic cases since in the majority, the serology remains positive, although it may decrease. In acute cases, 70% cure with NF and 75% with BNZ is achieved. In congenital cases, 100% cure is obtained if the treatment is performed during the first year of life. In chronic acquired cases, 20% cure and 50% improvement of the electrocardiographic changes are obtained with itraconazole.

Antitumor activity of nifurtimox observed in a patient with neuroblastoma

BACKGROUND

Chemotherapy-resistant neuroblastoma is a difficult disease to treat with poor survival.

OBSERVATIONS

We treated a patient with neuroblastoma who had progressed on conventional chemotherapy. This 5-year-old girl with chemotherapy-resistant neuroblastoma developed Chagas disease at the start of salvage chemotherapy for which she was also started on nifurtimox. The neuroblastoma response to these treatments resulted in clinical remission. In vitro, treatment of a neuroblastoma cell line with nifurtimox resulted in decreased cell viability whereas no effect was seen on an endothelial cell line.

CONCLUSIONS

Nifurtimox shows promise as a potential new treatment for neuroblastoma and warrants further testing.

Treatment of human African trypanosomiasis--present situation and needs for research and development

Human African trypanosomiasis re-emerged in the 1980s. However, little progress has been made in the treatment of this disease over the past decades. The first-line treatment for second-stage cases is melarsoprol, a toxic drug in use since 1949. High therapeutic failure rates have been reported recently in several foci. The alternative, eflornithine, is better tolerated but difficult to administer. A third drug, nifurtimox, is a cheap, orally administered drug not yet fully validated for use in human African trypanosomiasis. No new drugs for second-stage cases are expected in the near future. Because of resistance to and limited number of current treatments, there may soon be no effective drugs available to treat trypanosomiasis patients, especially second-stage cases. Additional research and development efforts must be made for the development of new compounds, including: testing combinations of current trypanocidal drugs, completing the clinical development of nifurtimox and registering it for trypanosomiasis, completing the clinical development of an oral form of eflornithine, pursuing the development of DB 289 and its derivatives, and advancing the pre-clinical development of megazol, eventually engaging firmly in its clinical development. Partners from the public and private sector are already engaged in joint initiatives to maintain the production of current drugs. This network should go further and be responsible for assigning selected teams to urgently needed research projects with funds provided by industry and governments. At the same time, on a long term basis, ambitious research programmes for new compounds must be supported to ensure the sustainable development of new drugs.

Interleukin (IL)-6, IL-8 and IL-10 in serum and CSF of Trypanosoma brucei gambiense sleeping sickness patients before and after treatment

Serum and cerebrospinal fluid (CSF) concentrations of interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor-alpha and interferon-gamma were determined in 46 Trypanosoma brucei gambiense sleeping sickness patients in DR Congo, before and after treatment. According to their CSF cell number before treatment, patients were classified as early-stage (0-5 cells/microL), intermediate-stage (6-20 cells/microL) or late-stage patients (> 20 cells/microL). In serum, slightly higher IL-8 concentrations were found in early-stage patients compared to intermediate- or late-stage patients. These high IL-8 levels dropped after treatment. Higher IL-10 concentrations were detected in serum of patients in intermediate or late stage compared to early-stage patients. In both intermediate- and late-stage groups, serum IL-10 decreased after treatment. In CSF, elevated concentrations of IL-6, IL-8 and especially of IL-10 were observed in late-stage T. b. gambiense patients. After treatment, these concentrations dropped to levels similar to those of the other patients. Tumour necrosis factor-alpha was detected only in a few serum and CSF samples, which were scattered over the different patient groups. Interferon-gamma was detected in serum of 5 patients and remained undetectable in CSF.

Nifurtimox plus pyrimethamine for treatment of murine toxoplasmosis

In the search for novel antitoxoplasmic agents, we evaluated the efficacy of nifurtimox (3-methyl-4[5'-nitrofurfurylidene-amino]-tetrahydroe-4H-1,4- thiazine-1,1-dioxide), an antiprotozoal drug effective against trypanosomiasis, in an experimental model of acute toxoplasmosis in mice. One hundred NIH mice were inoculated intraperitoneally, each with 2,614 RH tachyzoites of Toxoplasma gondii, and randomly allocated into 5 groups (n = 19-21). Animals from each group were orally treated for 10 days either with nifurtimox 25 mg/kg/day (NF1), nifurtimox 50 mg/kg/day (NF2), pyrimethamine 60 mg/kg/day (P), the combination nifurtimox 50 mg/kg/day plus pyrimethamine 60 mg/kg/day (NF2-P), or with corn oil (controls). Survival of mice was recorded daily for 1 mo after the experimental infection. Comparisons of cumulative mortality between groups were made applying the chi2 test. Mean survival time was longer in animals from P and NF2-P groups than those from NF1, NF2, and control groups. Cumulative mortality was less in mice from the NF2-P group (25%), than that in mice from the P (65%), the NF1 (100%), the NF2 (89%), or the control (95%) groups (P < 0.01). The doses of nifurtimox used in the present study were not significantly effective against murine toxoplasmosis. However, when combined with pyrimethamine, a strong anti-toxoplasma effect was obtained in comparison with survival rates associated with pyrimethamine or nifurtimox alone. It seems feasible that nifurtimox inhibits the replication of T. gondii tachyzoites similar to that of other protozoans, e.g., Trypanosoma and Leishmania. It will be important to determine if the reduction of mortality in mice treated with the nifurtimox-pyrimethamine combination results from summation or from synergism. Further studies on the toxic mechanisms exerted by nifurtimox on T. gondii seem warranted.

Etiological drug treatment of human infection by Trypanosoma cruzi

Forty-nine American Trypanosomiasis (Chagas' disease) patients, with xenodiagnosis proven parasitemia were treated by the authors. Forty-one of these patients were given benznidazole, at dosages ranging from 5mg/kg/day to 8mg/kg/day, during a pre-established period of 60 days. In this group, 17 patients had an undetermined form of the disease, whereas 22 had cardiologic disease and 4 had digestive disease (two patients had a mixed form of the disease). Side effects were frequent, and led to the discontinuation of treatment in 17 patients. The follow-up period ranged from 1 to 20 years (mean follow-up period of 6 yrs. 7 mo). 26 (63.4%) of the patients became parasitemia-negative. The other eight patients were treated with nifurtimox, during 120 days, following a variable dose regime of 5mg/kg/day (initial dose) to 17 mg/kg/day (final dose). Six of them had severe side effects, and only one patient remained parasitemia-negative throughout the observation period (ranging from 1 to 18 years). Benznidazole proved to be better tolerated and more effective in the management of parasitemia when compared to nifurtimox, although more effective and less toxic drugs are still desirable.

The disposition of nifurtimox in the rat isolated perfused liver: effect of dose size

The disposition of nifurtimox was studied in the rat isolated perfused liver using a recirculating system. The drug was administered as a bolus (5.0, 15.0 or 30.0 micrograms mL-1), and its disappearance was monitored by analysing perfusate samples. In all experiments perfusate disappearance was monoexponential, and no significant difference was found between the three doses for the elimination constant (0.016, 0.011 and 0.012 min-1, respectively), half-life (46.6, 65.8 and 66.8 min, respectively), extraction rate (0.128, 0.091 and 0.099, respectively) and distribution volume (41.1, 47.3 and 30.7 mL g-1, respectively). At 30 micrograms mL-1 the hepatic clearance was lower than the other concentrations of nifurtimox (0.66, 0.51 and 0.34 mL min-1 g-1, respectively). Relatively little parent drug was recovered from the liver at the end of the perfusions. In summary, nifurtimox is cleared slowly from the rat isolated perfused liver, is poorly extracted by hepatocyte cells and is completely metabolized from 2 to 4 h after perfusion.

High-dose nifurtimox for arseno-resistant Trypanosoma brucei gambiense sleeping sickness: an open trial in central Zaire

Thirty patients with arseno-resistant Trypanosoma brucei gambiense sleeping sickness were treated with high-dose nifurtimox (30 mg/kg/d for 30 d). During treatment, the cerebrospinal fluid (CSF) white blood cell (WBC) count decreased in all patients except one (mean CSF WBC count before nifurtimox: 117/mm3; after nifurtimox: 25/mm3), and trypanosomes disappeared from the CSF of all 9 patients in whom parasites had been demonstrated before nifurtimox. Among 25 patients seen at least once after treatment, 9 (36%) have relapsed so far. High-dose nifurtimox was significantly toxic: one patient died during treatment and 8 others developed adverse neurological effects. High-dose nifurtimox seems more effective than the previously used regimen (15 mg/kg/d for 60 d), but at the expense of significant toxicity.

[Changes in parasitemia evaluated using the modified Strout method in patients with acute Chagas disease under treatment]

Em 18 pacientes com doença de Chagas aguda foi semiquantificada a parasitemia, pelo método de Strout modificado, antes e durante o tratamento. Antes da terapêutica a parasitemia variou entre 1 e 104 tripanossomos, e após o início do tratamento a parasitemia foi lida repetidamente com um intervalo, na maioria dos casos, entre dois e cinco dias, até a negativação. A dose inicial dos medicamentos foi de 10 a 15mg/kg/dia de Nifurtimox para sete pacientes, e 10 a 20mg/kg/dia de Benzonidazol para onze indivíduos. Após início do tratamento com Nifurtimox um paciente ficou o mínimo de cinco e dois o máximo de 23 dias com parasitemia enquanto com o Benzonidazol um paciente permaneceu o máximo de 15 dias.com parasitemia patente. O Benzonidazol baixou a parasitemia mais rapidamente que o Nifurtimox

Trypanocidal drugs and the role of kidney forms of Trypanosoma (Herpetosoma) musculi in immunity of mice against reinfection

Adrenals, hearts, kidneys, livers, lungs, and spleens were removed from C3H/Anf mice which had been inoculated with Trypanosoma (Herpetosoma) musculi and no longer exhibited parasitemias. Imprints of each organ were examined microscopically, and each was homogenized and injected into recipient mice. It was confirmed that trypanosomes could be detected only in the donor kidneys. Lampit or Ethidium treatment eliminated bloodstream and kidney forms when administration was initiated after the development of patent parasitemias. However, mice treated with Lampit on the same day they were inoculated with T. musculi developed parasitemias later than animals injected with drug after parasites had appeared in their blood. Both Lampit and Ethidium depressed antibody production as detected in enzyme-linked immunosorbent assays of antisera from animals having parasitemias at the time of treatment. The elimination of kidney forms by Lampit or Ethidium treatment did not reduce the resistance of mice to reinfection by T. musculi 12 weeks or 15 and 22 weeks, respectively, after the initial inoculation of these animals with the parasites. Kidney forms were not required for the sustained protective immunity of the mice against reinfection during the intervals of these experiments.

The effect of Lampit on Trypanosoma rangeli in experimentally infected mice

Mice experimentally inoculated with metacyclic forms of Trypanosoma rangeli were given orally 10, 25, 50 or 100 mg/kg of body weight/day of Lampit on 20 consecutive days. The results of combined examinations of fresh blood, Giemsa stained blood preparations, blood cultures, blood concentration, repeated xenodiagnosis with Rhodnius prolixus and blind passages via triatomine bites to other mice demonstrated that a dose of 50 to 100 mg/kg/day of the drug eliminated T. rangeli from the blood of all mice in the first seven days of treatment. In mice receiving 10 or 25 mg/kg/day of drug, 60% and 30% respectively still harboured trypanosomes 90 days after infection. The results indicate that Lampit is at least as effective against T. rangeli as it is against T. cruzi in mice.

Further trials of nifurtimox in mucocutaneous leishmaniasis

At a dosage level of 8 to 10 mg/kg body-weight daily for 120 days nifurtimox was associated with clinical healing of cutaneous leishmaniasis in five of eight patients. At a dosage level of 20 mg/kg body-weight daily for 10 days in six of 10 patients the skin ulcer healed. Results and the reasons why both schemes are impracticable are briefly discussed.

A preliminary trial of nifurtimox in the treatment of onchocerciasis

Nifurtimox tablets were given at a dose of 15-20 mg per kg bodyweight daily for 5 days to 14 patients with onchocerciasis in the savanna of Cameroon. In general the therapy was well tolerated. During the course there were no clinical signs of microfilaricidal effects. 6 patients were re-examined after an interval of 8 months. The microfilarial load had decreased in 3 patients, while it was unchanged in 2, and increased in the last. There was no improvement in ocular lesions. These preliminary results suggest a possible effect on the adult parasite, and further trials are justified.