Active clinical trials for "Malaria"

A randomised, placebo-controlled, dose-escalation study to investigate safety and toleration of OZ439 OD for 3 days to healthy male and female volunteers. The study aims: To determine the safety and tolerability of ascending doses of OZ439 OD for three days. To assess pharmacokinetic parameters of ascending doses of OZ439 given OD. To identify the maximum tolerated dose of OZ439 administered.

This is an open label, multi-centre phase I/IIa sporozoite-challenge trial to assess the safety, immunogenicity and efficacy of two combination ChAd63-MVA heterologous prime-boost vaccination regimens. All volunteers recruited will be healthy, malaria naïve adults aged between 18 and 45 years. To determine the efficacy of each of two combinations of heterologous prime-boost immunisation strategies: ChAd63-MVA ME-TRAP combined with ChAd63-MVA CS ChAd63-MVA ME-TRAP combined with ChAd63-MVA CS and ChAd63-MVA AMA1 The study will be conducted at the University of Oxford's Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), Oxford, UK and the Wellcome Trust Clinical Research Facility in Southampton, UK. The malaria challenge will take place at the insectary at Imperial College (Infection and Immunity Section) in London, UK.

Malaria, a disease caused by the parasite Plasmodium, is one of the world's major infectious diseases. With approximately 627.000 deaths a year, there is desperate need for an effective vaccine. Though a number of vaccine-candidates have been developed, they have yet to achieve the level of efficacy necessary to eliminate malaria. It has been shown previously that healthy human volunteers bitten by malaria-infected mosquitoes while taking chloroquine, medicine that prevents malaria, are fully protected against a subsequent malaria challenge. This is called CPS-immunization. The unprecedented effectiveness of CPS-immunization makes it a good model to identify what immune responses protect against malaria, to further guide vaccine development. In this study we will use CPS-immunization to induce protection against malaria in healthy subjects and then analyse their immune response to a malaria challenge infection.

This study will randomize 30 healthy adult participants to one of three cohorts comprised of six groups of 5 individuals per group to simultaneously receive PfSPZ Challenge via the ID route. The goal will be to determine the optimal dose required to achieve 100% infectivity (ID100) of adult volunteers with P. falciparum malaria.

The purpose of this protocol is to perform Phase 1 (safety/toxicity and pharmacokinetic) Studies of an investigational aminoquinoline antimalarial (AQ-13) in human subjects. The compound to be studied (AQ-13) is being examined because it is active in vitro against Plasmodium falciparum malaria parasites resistant to chloroquine (CQ) and other antimalarials (multi-resistant P. falciparum), and because its safety was similar to that of CQ in preclinical studies performed by SRI International (IND 55,670). AQ-13 was also selected for study because it is active in vivo in two monkey models of human malaria: 1] P. cynomolgi in the rhesus monkey (Macaca mulatta), a model of human infection with P. vivax, and 2] CQ-resistant P. falciparum in the squirrel monkey, a model of human infection with CQ-resistant P. falciparum.

The study is a randomized open label clinical trial to verify the reproducibility of a sporozoite challenge model for Plasmodium vivax in humans. The verification of the reproducibility of such a model will make it possible to evaluate the efficacy of candidate P. vivax vaccines in Phase 2a trials. The study is divided into two successive steps: Step A Parasite Blood Donation: Volunteers will be recruited passively from a group of patients who present with active P. vivax infection and accept to donate infected blood. Samples of P. vivax infected blood will be collected and will be screened for infectious diseases, according to standard blood bank procedures. Colonized Anopheles albimanus mosquitoes will be fed with this blood using a Membrane Feeding Assay (MFA). Sixteen (16) days after, selected positive mosquito batches will be used for step B. Step B Challenge: After informed consent signature, a total of 18 healthy volunteers will be randomly allocated to Groups 1, 2 and 3, of 6 volunteers each and will be challenged with the bite of 3±1, P. vivax infected mosquitoes. Each group will be exposed to a different isolated parasite. Volunteers will be closely monitored post infection, and will be treated as soon as blood infection becomes patent as ascertained by microscopic examination of thick blood smears (TBS). Comparison of data obtained in the three different groups will be used to determine reproducibility of challenge model. Primary objective: To demonstrate that naïve human volunteers can be safely and reproducibly infected by the bite of An. albimanus mosquitoes carrying P. vivax sporozoites in their salivary glands. Secondary objective: To determine the influence of the type of parasite isolated on reproducibility and safety of the challenge model with P. vivax in human volunteers Hypothesis:It is possible to safely develop a reproducible P. vivax infection in human volunteers using P. vivax experimentally infected An. albimanus mosquitoes.

The overall objective is to evaluate the effect of exposure to Plasmodium (P.) falciparum erythrocytic stage antigens during different periods of infancy on the development of naturally acquired immunity (NAI). Hypothesis: Exposure to P. falciparum prior to 5 months of age does not result in the development of NAI, while exposure to P. falciparum after 5 months of age leads to the development of NAI. The risks of clinical malaria and anaemia during the second year of life will be compared between cohorts, as well as their correlations with the type and quality of immune responses (antibodies to several P. falciparum antigens, cytokines), oxidative stress markers and host genetic factors. These results should shed light on the determinants of the development of anti-P. falciparum responses early in life and the potential constraints to early life immunisation.

Even with optimal anti-malaria therapy and supportive care, severe and cerebral malaria are associated with a 10-30% mortality rate and neurocognitive deficits in up to 33% of survivors. Adjunctive therapies that modify host immune-pathological processes may further improve outcome over that possible with anti-malarials alone. Investigators aim to evaluate a PPARγ agonist ( "rosiglitazone") as adjunctive therapy for severe malaria.

The primary objective of the study is to demonstrate and quantify the protective efficacy (PE) of spatial repellent products in reducing the incidence of malaria infection in human cohorts. The null hypothesis (H0) is that there is no difference in malaria incidence between intervention and control arms.

Both artemether-lumefantrine and chloroquine are currently used and recommended by Malaysian Ministry of Health as blood stage treatments for non-severe P. vivax and P. knowlesi malaria. Microscopic misdiagnosis between Plasmodium species remains a large issue in Sabah, Malaysia and elsewhere. In order to facilitate potential policy change to a unified ACT guideline for all malaria species in Sabah artemether-lumefantrine needs to be evaluated for P. vivax malaria. Preliminary data in a recently completed RCT evaluating artesunate-mefloquine vs chloroquine for P. vivax showed up to 36% P. vivax recurrence with chloroquine monotherapy by day 28 post treatment without primaquine. Based on these data blood stage chloroquine treatment failure rates should also be evaluated in the context of standard concurrent (rather than delayed) liver stage primaquine dosing, due to both its potential blood stage synergistic effect in addition to known decreased recurrence rates. As artemether-lumefantrine is one of the current first line Ministry of Health ACTs used in Sabah with a lower adverse event profile compared to artesunate-mefloquine, this was recommended as the more appropriate ACT to evaluate against chloroquine.