SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Nifurtimox

167

BACKGROUND: With declining vectorial transmission, Chagas disease predominantly affects adults nowadays. The efficacy of nifurtimox in the chronic phase in adult patients is poorly known, particularly in regions where there is no risk of reinfection. Recommendations for treatment outcome assessment rely on serological follow-up. We evaluated the serological and parasitological response to nifurtimox in a cohort of adult patients three years post-treatment in Switzerland. METHODS: Patients treated with nifurtimox in 2008 during a cross-sectional study in Geneva, Switzerland, were contacted for follow-up in 2011. Two ELISAs and a rapid immunochromatographic test were used to test 2008 and 2011 serum samples simultaneously. In addition, conventional and real-time PCR were performed on 2011 samples. RESULTS: Thirty-seven (84.1%) of 44 eligible patients, predominantly female, middle-aged, Bolivians at the indeterminate stage, were enrolled. All 2011 ELISA and immunochromatographic tests were positive. Twenty-eight (75.7%) patients presented a lower optical density (OD) in 2011 compared to 2008. This OD difference was significant in both commercial (P < 0.001) and in-house (P = 0.002) ELISAs. Agreement between the two ELISAs was low (Kappa = 0.469). All patients had negative conventional PCR results but one (2.7%) was positive with real-time PCR. CONCLUSION: Our results highlight the inadequacy of serology for assessing response in adults, three years after treatment. In our cohort, 97.3% had results that could either indicate treatment failure or persistant humoral response despite treatment. The lack of accurate early post-treatment tests of cure prevents appropriate patients information and councelling. New follow-up tests are needed to assess treatments efficacy given the large adult population in need of antiparasitic therapy.

Concepts: Antibody, Epidemiology, Infectious disease, Polymerase chain reaction, Chagas disease, Serology, Antiparasitic, Nifurtimox

28

Chagas disease chemotherapy, currently based on only two drugs, nifurtimox and benznidazole, is far from satisfactory and therefore the development of new antichagasic compounds remains an important goal. On the basis of antichagasic properties previously described for some 1,2-disubstituted 5-nitroindazolin-3-ones (21, 33) and in order to initiate the optimization of activity of this kind of compounds, we have prepared a series of related analogs (22-32, 34-38, 58 and 59) and tested in vitro these products against epimastigote forms of Trypanosoma cruzi. 2-Benzyl-1-propyl (22), 2-benzyl-1-isopropyl (23) and 2-benzyl-1-butyl (24) derivatives have shown high trypanocidal activity and low unspecific toxicity. Other indazole derivatives with different substitution patterns (1-substituted 3-alkoxy-1H-indazoles and 2-substituted 3-alkoxy-2H-indazoles), arising from the synthetic procedures used to prepare the mentioned indazolinones, have moderate to low effectiveness. The exploration of SAR information using the concept of an activity landscape has been carried out with SARANEA software. We have also searched for structural similarities between 225 known antiprotozoan drugs and compound 22. The results confirm that compounds 22-24 constitute promising leads and that 5-nitroindazolin-3-one system is a novel anti-T. cruzi scaffold which may represent an important therapeutic alternative for the treatment of Chagas disease.

Concepts: Infectious disease, Chagas disease, Trypanosoma, Trypanosoma cruzi, Carlos Chagas, Trypanosoma rangeli, Nifurtimox, Benznidazole

26

Introduction: A century after its discovery, American trypanosomiasis or Chagas disease remains a serious health problem in Latin America, where it affects around 7 - 8 million people. The prevalence of Chagas disease in the poorer parts of the world has meant that it has largely been neglected with limited progress that made in identifying new drugs for the treatment. The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available for Chagas disease with limitations that include variable efficacy, long treatment courses and toxicity. Areas covered: This review focuses on different therapeutic strategies that have been used for the discovery of new treatments for Chagas disease. These include combination chemotherapy, drug repositioning, re-dosing regimens for current drugs and the identification of new drugs with specified target profiles. Expert opinion: There are currently several reasons for a more optimistic view about chemotherapy with Chagas disease. However, despite some progress being made in preclinical studies, there is yet to be an ideal drug or formulation for human treatment. One major drawback in the evaluation of potential Chagas disease therapeutics is the lack of tools available to perform the said evaluation. Indeed, there is a great need to discover a better biomarker that could determine the efficacy of potential chemotherapeutics in treated patients.

Concepts: Medicine, Infectious disease, Chagas disease, Trypanosoma, Trypanosoma cruzi, Neglected diseases, Nifurtimox, Benznidazole

6

The control or elimination of neglected tropical diseases (NTDs) has targets defined by the WHO for 2020, reinforced by the 2012 London Declaration. We estimated the economic impact to individuals of meeting these targets for human African trypanosomiasis, leprosy, visceral leishmaniasis and Chagas disease, NTDs controlled or eliminated by innovative and intensified disease management (IDM).

Concepts: Infectious disease, Chagas disease, Parasitic diseases, African trypanosomiasis, Neglected diseases, Tropical disease, Nifurtimox, Tropical diseases

5

 Nifurtimox is one of only two medications available for treating Chagas disease, and currently the only drug available in the United States (US), but its safety and tolerance has not been extensively studied. This is the first study to evaluate tolerance of nifurtimox in US patients with Chagas disease.

Concepts: Infectious disease, United States, Chagas disease, Poverty in the United States, U.S. state, Pharmaceutical drug, American football, Nifurtimox

2

The WHO recognizes human African trypanosomiasis, Chagas disease and the leishmaniases as neglected tropical diseases. These diseases are caused by parasitic trypanosomatids and range in severity from mild and self-curing to near invariably fatal. Public health advances have substantially decreased the effect of these diseases in recent decades but alone will not eliminate them. In this Review, we discuss why new drugs against trypanosomatids are required, approaches that are under investigation to develop new drugs and why the drug discovery pipeline remains essentially unfilled. In addition, we consider the important challenges to drug discovery strategies and the new technologies that can address them. The combination of new drugs, new technologies and public health initiatives is essential for the management, and hopefully eventual elimination, of trypanosomatid diseases from the human population.

Concepts: Infectious disease, Chagas disease, African trypanosomiasis, Vector, Neglected diseases, Tropical disease, Nifurtimox, Tropical diseases

2

Current therapeutic options for Chagas' disease are limited to benznidazole and nifurtimox, which have been associated with low cure rates in the chronic stage of the disease and which have considerable toxicity. Posaconazole has shown trypanocidal activity in murine models.

Concepts: Medicine, Infectious disease, Randomized controlled trial, Cure, Chagas disease, The Chronic, Nifurtimox, Benznidazole

0

Interest in nitroheterocyclic drugs for the treatment of infectious diseases has undergone a resurgence in recent years. Here we review the current status of monocyclic and bicyclic nitroheterocyclic compounds as existing or potential new treatments for visceral leishmaniasis, Chagas' disease and human African trypanosomiasis. Both monocyclic (nifurtimox, benznidazole and fexinidazole) and bicyclic (pretomanid (PA-824) and delamanid (OPC-67683)) nitro-compounds are prodrugs, requiring enzymatic activation to exert their parasite toxicity. Current understanding of the nitroreductases involved in activation and possible mechanisms by which parasites develop resistance is discussed along with a description of the pharmacokinetic / pharmacodynamic behaviour and chemical structure-activity relationships of drugs and experimental compounds.

Concepts: Infectious disease, Chagas disease, Parasitic diseases, African trypanosomiasis, Vector, Neglected diseases, Tropical disease, Nifurtimox

0

Nowadays, the pharmacological therapy for the treatment of Chagas disease is based on two old drugs, benznidazole and nifurtimox, which have restricted efficacy against the chronic phase of the illness. To overcome the lack of efficacy of the traditional drugs (and their considerable toxicity), new molecular targets have been studied as starting points to the discovery of new antichagasic compounds. Among them, polyamine transporter TcPAT12 (also known as TcPOT1.1) represents an interesting macromolecule, since polyamines are essential for Trypanosoma cruzi, the parasite that causes the illness, but it cannot synthesize them de novo. In this investigation we report the results of a combined ligand- and structure-based virtual screening for the discovery of new inhibitors of TcPAT12. Initially we filtered out ZINC and Drugbank databases with similarity and QSAR models and then we submitted the candidates to a validated docking based screening. Four structures were selected and tested in T. cruzi epimastigotes proliferation and two of them, Cisapride and [2-(cyclopentyloxy)phenyl]methanamine showed inhibitory effects. Additionally, we performed transport assays which demonstrated that Cisapride interferes with putrescine uptake in a specific mode.

Concepts: Chagas disease, Enzyme inhibitor, Trypanosoma, Trypanosoma cruzi, Carlos Chagas, Polyamine, Trypanosoma rangeli, Nifurtimox

0

Chagas disease is a parasitic disease that mostly affects Latin American countries, but it has currently become a worldwide epidemic due to migration. Both drugs marketed for its treatment (benznidazole and nifurtimox) are associated with a high rate of adverse reactions. Benznidazole is preferred initially because of its more favourable toxicity profile and perceived greater efficacy. Hypersensitivity dermatological reactions, gastrointestinal and neurological disturbances represent the most common drug-related adverse events. General symptoms such as fever, arthralgia, myalgia or bone marrow depression (leucopaenia) are seen less frequently. We describe the case of a 33-year-old woman with chronic Chagas disease who presented with acute gingival bleeding and severe thrombocytopaenia, probably related to benznidazole treatment. Temporal association with drug initiation and recovery after treatment withdrawal were demonstrated. Clinicians should be aware of the possible association between immune thrombocytopaenia and benznidazole, even though the pathogenesis remains unclear at present.

Concepts: Immune system, Medicine, Infectious disease, Hospital, Bone marrow, Chagas disease, Nifurtimox, Benznidazole