Active clinical trials for "Malaria"

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.

A clinical trial aimed to standardize a vivax sporozoite infection model in human volunteers was conducted at the Malaria Vaccine and Drug Development Center (MVDC) in collaboration with the Immunology Institute at Valle State University and the Fundación Clínica Valle del Lili (FCVL) in Cali, Colombia. The primary objective was to determine if naïve human volunteers could be safely and reproducibly infected by the bite of An. albimanus mosquitoes carrying P. vivax sporozoites in their salivary glands and a secondary objective consisted in determining the minimal number of infected mosquitoes required to infect all volunteers, with a reproducible pre-patent period. The trial was divided into two steps: Step A directed to obtain human blood infected with P.vivax parasite used to infect anopheles mosquitoes and Step B to produce P. vivax sporozoites in Anopheles mosquitoes to determine the dose response of naive human volunteers exposed to 3 +/- 1, 6 +/- 1 y 9 +/- 1 mosquitoes bites. A total of 15 samples of P. vivax infected donors were used to infect different batches of mosquitoes.

A randomized double-blind controlled trial will be carried out in which young, nulliparous (having never given birth) women will be randomly assigned to receive weekly supplementation with either iron and folic acid or folic acid alone. Women will be followed-up weekly up to 18 months. Women who become pregnant will be followed-up until delivery. Malaria risk in both groups will be compared by assessing the prevalence of peripheral parasitaemia at the first antenatal clinic visit for pregnant women and at the end of the first malaria transmission season for non-pregnant women. The incidence of clinical malaria will be assessed by active and passive case detection throughout the follow-up period.

DDI study of Tafenoquine and Chloroquine

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.

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.

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.