Negligible exposure to nifurtimox through breast milk during maternal treatment for Chagas Disease

Chagas disease in immunocompromised patients

SUMMARYAs Chagas disease remains prevalent in the Americas, it is important that healthcare professionals and researchers are aware of the screening, diagnosis, monitoring, and treatment recommendations for the populations of patients they care for and study. Management of Trypanosoma cruzi infection in immunocompromised hosts is challenging, particularly because, regardless of antitrypanosomal treatment status, immunocompromised patients with Chagas disease are at risk for T. cruzi reactivation, which can be lethal. Evidence-based practices to prevent and manage T. cruzi reactivation vary depending on the type of immunocompromise. Here, we review available data describing Chagas disease epidemiology, testing, and management practices for various populations of immunocompromised individuals, including people with HIV and patients undergoing solid organ and hematopoietic stem cell transplantation.

Clinical trials for Chagas disease: etiological and pathophysiological treatment

Chagas disease (CD) is caused by the flagellate protozoan Trypanosoma cruzi. It is endemic in Latin America. Nowadays around 6 million people are affected worldwide, and 75 million are still at risk. CD has two evolutive phases, acute and chronic. The acute phase is mostly asymptomatic, or presenting unspecific symptoms which makes it hard to diagnose. At the chronic phase, patients can stay in the indeterminate form or develop cardiac and/or digestive manifestations. The two trypanocide drugs available for the treatment of CD are benznidazole (BZ) and nifurtimox (NFX), introduced in the clinic more than five decades ago. WHO recommends treatment for patients at the acute phase, at risk of congenital infection, for immunosuppressed patients and children with chronic infection. A high cure rate is seen at the CD acute phase but better treatment schemes still need to be investigated for the chronic phase. There are some limitations within the use of the trypanocide drugs, with side effects occurring in about 40% of the patients, that can lead patients to interrupt treatment. In addition, patients with advanced heart problems should not be treated with BZ. This is a neglected disease, discovered 114 years ago that still has no drug effective for their chronic phase. Multiple social economic and cultural barriers influence CD research. The high cost of the development of new drugs, in addition to the low economical return, results in the lack of investment. More economic support is required from governments and pharmaceutical companies on the development of more research for CD treatment. Two approaches stand out: repositioning and combination of drugs, witch drastically decrease the cost of this process, when compared to the development of a new drug. Here we discuss the progress of the clinical trials for the etiological and pathophysiological treatment for CD. In summary, more studies are needed to propose a new drug for CD. Therefore, BZ is still the best option for CD. The trials in course should clarify more about new treatment regimens, but it is already possible to indicate that dosage and time of treatment need to be adjusted.

A systematic review on maternal-to-infant transfer of drugs through breast milk during the treatment of malaria, tuberculosis, and neglected tropical diseases

BACKGROUND

Exclusive breastfeeding of infants under 6 months of age is recommended by the World Health Organization. In 2021, over 300 million combined incident cases of malaria, tuberculosis, and neglected tropical diseases (NTDs) were reported, predominantly in low-income countries. For many of the drugs used as first-line treatments for these conditions, there is limited knowledge on infant exposure through breastfeeding with poorly understood consequences. This review summarized available knowledge on mother-to-infant transfer of these drugs to inform future lactation pharmacokinetic studies.

METHODOLOGY

A list of first-line drugs was generated from the latest WHO treatment guidelines. Using standard online databases, 2 independent reviewers searched for eligible articles reporting lactation pharmacokinetics studies and extracted information on study design, participant characteristics, and the mathematical approach used for parameter estimation. A third reviewer settled any disagreements between the 2 reviewers. All studies were scored against the standardized "ClinPK" checklist for conformity to best practices for reporting clinical pharmacokinetic studies. Simple proportions were used to summarize different study characteristics.

FINDINGS

The most remarkable finding was the scarcity of lactation pharmacokinetic data. Only 15 of the 69 drugs we listed had lactation pharmacokinetics fully characterized. Most studies enrolled few mothers, and only one evaluated infant drug concentrations. Up to 66% of the studies used non-compartmental analysis to estimate pharmacokinetic parameters rather than model-based compartmental analysis. Unlike non-compartmental approaches, model-based compartmental analysis provides for dynamic characterization of individual plasma and breast milk concentration-time profiles and adequately characterizes variability within and between individuals, using sparsely sampled data. The "ClinPK" checklist inadequately appraised the studies with variability in the number of relevant criteria across different studies.

CONCLUSIONS/SIGNIFICANCE

A consensus is required on best practices for conducting and reporting lactation pharmacokinetic studies, especially in neglected diseases such as malaria, tuberculosis, and NTDs, to optimize treatment of mother-infant pairs.

Further Investigations of Nitroheterocyclic Compounds as Potential Antikinetoplastid Drug Candidates

Due to the lack of specific vaccines, management of the trypanosomatid-caused neglected tropical diseases (sleeping sickness, Chagas disease and leishmaniasis) relies exclusively on pharmacological treatments. Current drugs against them are scarce, old and exhibit disadvantages, such as adverse effects, parenteral administration, chemical instability and high costs which are often unaffordable for endemic low-income countries. Discoveries of new pharmacological entities for the treatment of these diseases are scarce, since most of the big pharmaceutical companies find this market unattractive. In order to fill the pipeline of compounds and replace existing ones, highly translatable drug screening platforms have been developed in the last two decades. Thousands of molecules have been tested, including nitroheterocyclic compounds, such as benznidazole and nifurtimox, which had already provided potent and effective effects against Chagas disease. More recently, fexinidazole has been added as a new drug against African trypanosomiasis. Despite the success of nitroheterocycles, they had been discarded from drug discovery campaigns due to their mutagenic potential, but now they represent a promising source of inspiration for oral drugs that can replace those currently on the market. The examples provided by the trypanocidal activity of fexinidazole and the promising efficacy of the derivative DNDi-0690 against leishmaniasis seem to open a new window of opportunity for these compounds that were discovered in the 1960s. In this review, we show the current uses of nitroheterocycles and the novel derived molecules that are being synthesized against these neglected diseases.

Selected Aspects of the Analytical and Pharmaceutical Profiles of Nifurtimox

Nifurtimox is a nitroheterocyclic drug employed for treatment of trypanosomiases (Chagas disease and West African sleeping sickness); its use for certain cancers has also been assessed. Despite having been in the market for over 50 years, knowledge of nifurtimox is still fragmentary and incomplete. Relevant aspects of the chemistry and biology of nifurtimox are reviewed to summarize the current knowledge of this drug. These comprise its chemical synthesis and the preparation of some analogues, as well as its chemical degradation. Selected physical data and physicochemical properties are also listed, along with different approaches toward the analytical characterization of the drug, including electrochemical (polarography, cyclic voltammetry), spectroscopic (ultraviolet-visible, nuclear magnetic resonance, electron spin resonance), and single crystal X-ray diffractometry. The array of polarographic, ultraviolet-visible spectroscopic, and chromatographic methods available for the analytical determination of nifurtimox (in bulk drug, pharmaceutical formulations, and biological samples), are also presented and discussed, along with chiral chromatographic and electrophoretic alternatives for the separation of the enantiomers of the drug. Aspects of the drug likeliness of nifurtimox, its classification in the Biopharmaceutical Classification System, and available pharmaceutical formulations are detailed, whereas pharmacological, chemical, and biological aspects of its metabolism and disposition are discussed.

Review of pharmacological options for the treatment of Chagas disease

Chagas disease (CD) is a worldwide problem, with over 8 million people infected in both rural and urban areas. CD was first described over a century ago, but only two drugs are currently available for CD treatment: benznidazole (BZN) and nifurtimox (NF). Treating CD-infected patients, especially children and women of reproductive age, is vital in order to prevent long-term sequelae, such as heart and gastrointestinal dysfunction, but this aim is still far from being accomplished. Currently, the strongest data to support benefit-risk considerations come from trials in children. Treatment response biomarkers need further development as serology is being questioned as the best method to assess treatment response. This article is a narrative review on the pharmacology of drugs for CD, particularly BZN and NF. Data on drug biopharmaceutical characteristics, safety and efficacy of both drugs are summarized from a clinical perspective. Current data on alternative compounds under evaluation for CD treatment, and new possible treatment response biomarkers are also discussed. Early diagnosis and treatment of CD, especially in paediatric patients, is vital for an effective and safe use of the available drugs (i.e. BZN and NF). New biomarkers for CD are urgently needed for the diagnosis and evaluation of treatment efficacy, and to guide efforts from academia and pharmaceutical companies to accelerate the process of new drug development.

Screening for Chagas Disease during Pregnancy in the United States-A Literature Review

Obstetrician-gynecologists in the United States have little clinical experience with the epidemiology, pathophysiology, diagnosis, and treatment of Chagas disease. The number of US parturients born in Central and South America has continued to increase over the last 20 years, making US obstetricians more and more likely to care for Chagas-infected mothers who may never be identified until dealing with long-term consequences of the disease. A literature search demonstrates that few US obstetric care providers recognize the risk of vertical transmission for the neonate and the missed opportunity of infant treatment to decrease disease prevalence. Most women will be asymptomatic during pregnancy, as will their neonates, making routine laboratory screening a necessity for the identification of at-risk neonates. While the benefits of treating asymptomatic women identified in pregnancy are not as clear as the benefits for the infants, future health screenings for evidence of the progression of Chagas disease may be beneficial to these families. The literature suggests that screening for Chagas in pregnancy in the US can be done in a cost-effective way. When viewed through an equity lens, this condition disproportionately affects families of lower socioeconomic means. Improved education of healthcare providers and appropriate resources for diagnosis and treatment can improve this disparity in health outcomes.

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

Clinical investigation of the biopharmaceutical characteristics of nifurtimox tablets - Implications for quality control and application

Nifurtimox is approved in Chagas disease and has been used in endemic countries since the 1960s. Nifurtimox, available as a 120 mg tablet, is administered with food typically three times daily, and dose is adjusted for age and bodyweight. Accurately or reproducibly fragmenting the 120 mg tablet for dose adjustment in young children and those with low bodyweight is problematic. Based on the existing tablet formulation, new nifurtimox 30 mg and 120 mg tablets have been developed in a format that can be divided accurately into 15 mg and 60 mg fragments. In adults with chronic Chagas disease, we investigated whether nifurtimox bioavailability is affected by tablet dissolution rate, and whether different diets affect nifurtimox bioavailability. In an open-label, three-period cross-over study (n=36; ClinicalTrials.gov, NCT03350295), patients randomly received three 30 mg tablet formulations (slow, medium, or fast dissolution; a 4 × 30 mg dose of one formulation per period). In an open-label, four-period cross-over study (n=24; ClinicalTrials.gov, NCT03334838) patients randomly fasted or received one of three meal types (high-fat/high-calorie, low-fat, dairy-based) before ingesting nifurtimox (a 4 × 30 mg dose per period). Acceptance criteria for no difference between groups were 90% confidence intervals (CIs) of exposure ratios in the range 0.8-1.25. Nifurtimox bioavailability was unaffected by tablet dissolution kinetics. Ratios of area under the curve at final assessment (AUC_(0-tlast) [90% CI]) were: fast/medium dissolution, 1.061 (0.990-1.137); slow/medium dissolution, 0.964 (0.900-1.033); fast/slow dissolution, 1.100 (1.027-1.179). Compared with a fasting state, nifurtimox bioavailability increased by 73% after a high-fat/high-calorie meal (AUC_(0-tlast) ratio [90% CI], 1.732 [1.581-1.898]); smaller increases were seen with the other meal types (low-fat: 1.602 [1.462-1.755]; dairy-based: 1.340 [1.222-1.468]). Although type of diet can affect bioavailability, taking nifurtimox with food is most important.

Biopharmaceutical Characteristics of Nifurtimox Tablets for Age- and Body Weight-Adjusted Dosing in Patients With Chagas Disease

Treatment of Chagas disease with nifurtimox requires age‐ and body weight‐adjusted dosing, resulting in complex dosing instructions. Appropriate formulations are needed for precise and compliant dosing, especially in pediatric patients. We characterized the biopharmaceutical features of a standard nifurtimox 120‐mg tablet and a 30‐mg tablet developed to improve dose accuracy. Two open‐label, randomized crossover studies were conducted in adult outpatients with Chagas disease. One study investigated whether 4 × 30‐mg tablets and 1 × 120‐mg tablet were bioequivalent and whether tablets can be administered as an aqueous slurry without affecting bioavailability. The second study investigated the effect of a high‐calorie/high‐fat diet versus fasting on the absorption of nifurtimox after a single 4 × 30‐mg dose. Interventions were equivalent if the 90% confidence interval (CI) of their least‐squares (LS) mean ratios for both AUC_0‐tlast and C_max were in the range of 80%‐125%. The 4 × 30‐mg and 1 × 120‐mg tablet doses were bioequivalent (AUC_0‐tlast: LS mean ratio, 104.7%; 90%CI, 99.1%‐110.7%; C_max: LS mean ratio, 101.7%; 90%CI, 89.4%‐115.6%; n = 24). Exposure when giving the 4 × 30‐mg dose as a slurry or as tablets was comparable, with an AUC_0‐tlast ratio of 93.2% (84.2%‐103.1%; n = 12) and a slightly decreased C_max ratio for the slurry of 76.5% (68.8%‐85.1%). Food improved the bioavailability of nifurtimox substantially (AUC_0‐tlast ratio_fed/fasted, 172%; 90%CI, 154%‐192%; C_max ratio_fed/fasted, 168%; 90%CI, 150%‐187%). The data indicate that the 30‐ and 120‐mg tablets are suitable for dosing adult and pediatric patients accurately; nifurtimox should be administered under fed conditions.

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

WHF IASC Roadmap on Chagas Disease

Background

Chagas Disease is a neglected tropical disease caused by the protozoan Trypanosoma cruzi, with some of the most serious manifestations affecting the cardiovascular system. It is a chronic, stigmatizing condition, closely associated with poverty and affecting close to 6 million people globally. Although historically the disease was limited to endemic areas of Latin America recent years have seen an increasing global spread. In addition to the morbidity and mortality associated with the disease, the social and economic burdens on individuals and society are substantial. Often called the 'silent killer', Chagas disease is characterized by a long, asymptomatic phase in affected individuals. Approximately 30% then go on develop chronic Chagas cardiomyopathy and other serious cardiac complications such as stroke, rhythm disturbances and severe heart failure.

Methods

In a collaboration of the World Hearth Federation (WHF) and the Inter-American Society of Cardiology (IASC) a writing group consisting of 20 diverse experts on Chagas disease (CD) was convened. The group provided up to date expert knowledge based on their area of expertise. An extensive review of the literature describing obstacles to diagnosis and treatment of CD along with proposed solutions was conducted. A survey was sent to all WHF Members and, using snowball sampling to widen the consultation, to a variety of health care professionals working in the CD global health community. The results were analyzed, open comments were reviewed and consolidated, and the findings were incorporated into this document, thus ensuring a consensus representation.

Results

The WHF IASC Roadmap on Chagas Disease offers a comprehensive summary of current knowledge on prevention, diagnosis and management of the disease. In providing an analysis of 'roadblocks' in access to comprehensive care for Chagas disease patients, the document serves as a framework from which strategies for implementation such as national plans can be formulated. Several dimensions are considered in the analysis: healthcare system capabilities, governance, financing, community awareness and advocacy.

Conclusion

The WHF IASC Roadmap proposes strategies and evidence-based solutions for healthcare professionals, health authorities and governments to help overcome the barriers to comprehensive care for Chagas disease patients. This roadmap describes an ideal patient care pathway, and explores the roadblocks along the way, offering potential solutions based on available research and examples in practice. It represents a call to action to decision-makers and health care professionals to step up efforts to eradicate Chagas disease.