Active clinical trials for "Malaria, Falciparum"

The study will determine if amodiaquine tablet (Pfizer), an antimalaria agent, is pharmaceutically equivalent to a comparator product (Arsuamoon-Guilin China).

This study aims to assess the safety and effectiveness of four new candidate malaria vaccines; ChAd63 CS, ChAd63 ME-TRAP, MVA CS & MVA ME-TRAP. These vaccines consist of viruses (ChAd63 and MVA) which have been genetically modified so (i) they cannot replicate in humans and (ii) they include parts of the malaria parasite; Plasmodium falciparum (CS and ME-TRAP). The hope is that these vaccines will induce immune responses in vaccinees that are able to prevent malaria. This proposed study will compare how effective ChAd63-MVA CS is at preventing malaria infection in UK volunteers following malaria challenge compared to ChAd63-MVA ME-TRAP. 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.

The study is designed to establish infectivity of Plasmodium falciparum sporozoites (PfSPZ) via intravenous (IV) administration in three groups with different malaria immunity-status: Adults with a history of lifelong malaria exposure without sickle cell trait (HbAA) Adults with a history of lifelong malaria exposure with sickle cell trait (HbAS) Adults without previous malaria episodes without sickle cell trait (HbAA) Initially a dose of 3,200 PfSPZ will be given and the time until thick blood smear positivity after challenge will be assessed. If in any of the groups with a history of lifelong malaria exposure, 50% or less of individuals become thick blood smear positive during the 28 days post injection of PfSPZ Challenge, the dose will be increased 4-fold to 12,800 PfSPZ in this group.

Malaria is one of the major infectious diseases in the world with a tremendous impact on the quality of life significantly contributing to the ongoing poverty in endemic countries. It causes almost one million deaths per year, the majority of which are children under the age of five. The malaria parasite enters the human body through the skin, by the bite of an infected mosquito. Subsequently, it invades the liver and develops and multiplies inside the hepatocytes. After a week, the hepatocytes burst open and the parasites are released in the blood stream, causing the clinical phase of the disease. As a unique opportunity to study malaria immunology and efficacy of immunisation strategies, a protocol has been developed in the past to conduct experimental human malaria infections (EHMIs). EHMIs generally involve small groups of malaria-naïve volunteers infected via the bites of P. falciparum infected laboratory-reared Anopheline mosquitoes. Although potentially serious or even lethal, P. falciparum malaria can be radically cured at the earliest stages of blood infection where risks of complications are virtually absent. The investigators have shown previously that healthy human volunteers can be protected from a malaria mosquito (sporozoite) challenge by immunization with sporozoites (by mosquito bites) under chloroquine prophylaxis (CPS immunization). However, it is unknown how many mosquito bites are necessary to confer protection. Moreover, as all volunteers were protected in this study, no correlates of protection could be established. For future development of vaccines and understanding of protective immunity to malaria, it is important to investigate the lowest dose of CPS immunization that confers 100% protection and to find correlates of protection. Therefore, the present study aims to make the CPS immunization protocol more sensitive by lowering the number of infected mosquito bites, in order to study the underlying mechanisms of protection.

In Malawi, the standard of care to prevent malaria during pregnancy at the time of the study was a two dose sulfadoxine-pyrimethamine intermittent protective treatment (SP IPT) regimen administered in the second and third trimester of pregnancy. In this investigation, this two dose strategy was compared to a monthly SP regimen. The objective for the study was to determine the efficacy of the different regimens for HIV positive and HIV negative women in the prevention of placental malaria.

The purpose of this study is to evaluate an experimental malaria vaccine for its ability to prevent malaria infection or disease in a blood-stage challenge model (when volunteers are infected with malaria parasites using malaria-infected red blood cells). The vaccine being testing is a protein called FMP2.1, which is given with an adjuvant (a substance to improve the body's response to a vaccination) called AS01B. The aim is to use this protein and adjuvant to help the body make an immune response against parts of the malaria parasite. This study will enable assessment of: The ability of the vaccine to prevent malaria infection. The safety of the vaccine in healthy participants. The response of the human immune system to the vaccine. This will be done by giving participants three vaccinations and then exposing them to malaria infection by transfusing a small number of red blood cells infected with malaria under carefully regulated conditions. Participants will be followed closely to observe if and when they develop malaria. If the vaccine provides some protection against malaria, participants will take longer to develop malaria than usual or will not develop malaria at all. The study will enrol 15 participants to be vaccinated and then challenged with malaria in addition to recruit 15 individuals to be control subjects.

This is a clinical trial in which healthy volunteers will be administered experimental malaria vaccines. One group of volunteers will receive vaccination with the leading malaria vaccine candidate, RTS,S/AS01. This vaccine schedule will consist of 3 doses of RTS,S/AS01 with an interval of 4 weeks between doses (Doses given at 0,4 and 8 week timepoints). Another group will receive a vaccination schedule composed of the same dosage and timing regimen of RTS,S, but they will also receive vaccination with ChAd63 ME-TRAP, 2 weeks after the first RTS,S followed 8 weeks later by vaccination with MVA ME-TRAP (2 and 10 week timepoints). The study will assess the safety of the vaccinations, and the immune responses to vaccination. Immune responses are measured by tests on blood samples. Volunteers will be infected with malaria by mosquito bites, 12 weeks after the first vaccination. In addition, a group of volunteers not receiving vaccines will also be infected with malaria by the same method. These infection experiments will be used to assess vaccine efficacy: how well the vaccines act to prevent malaria disease. A further single volunteer may also be infected with malaria; this volunteer participated in a previous trial where they received vaccines and was completely protected against malaria disease after infection by mosquito bite. The RTS,S/AS01 vaccine is a protein (RTS,S) mixed with an adjuvant (AS01). The ChAd63 ME-TRAP and MVA ME-TRAP vaccines are called viral vectored vaccines. They are made from viruses which are modified so that they can not multiply. The viruses have extra DNA in them so that after injection, the body makes malaria proteins (but malaria does not develop), so that the immune system builds a response to malaria without having been infected by it. Healthy volunteers will be recruited in England at three research sites: in Oxford, London and Southampton.

The study will determine if artesunate tablet (Pfizer), an antimalarial agent, is pharmaceutically equivalent to Arsuamoon® tablets (Guilin-China).

The primary goal of this study is to quantify the benefit of adding artesunate to amodiaquine in treating patients with uncomplicated P. falciparum malaria, in a low transmission area in Colombia. The benefit will be assessed in terms of: Efficacy Tolerability Time of fever clearance Time of parasite clearance Proportion of gametocyte carriers

This is a single-center, open label study. The primary aim of this project is to develop a controlled human malaria infection transmission model ("CHMI-trans") or "challenge model" to evaluate the capacity of vaccines, biologics (monoclonal antibodies, or mAbs), and drugs to block malaria parasite transmission by assessing infectiousness of Plasmodium falciparum (Pf) gametocyte carriers for Anopheles mosquitoes.