Single-Dose Tafenoquine to Prevent Malaria Relapse

MedicalResearch.com Interview with:
Malaria CDC imageGavin C.K.W. Koh, MB BChir MA PhD MCRP DTM&H

Department of Drug Discovery Unit for Diseases of the Developing World
GlaxoSmithKline | GSK

MedicalResearch.com: What is the background for this study?

Response: Malaria still remains one of the greatest global healthcare challenges so, as part of GSK’s efforts to fight diseases that disproportionately impact the poorest, we have been working on tafenoquine as a potential medicine for malaria for over 20 years.  In 2008, GSK entered into a collaboration with the not-for-profit product development partnership, Medicines for Malaria Venture (MMV), to develop tafenoquine as an anti-relapse medicine for patients infected with a particular species of malaria called Plasmodium vivax malaria.

  1. vivaxmalaria is estimated to cause around 7.5 million clinical infections every year. The disease may cause fever, chills, vomiting, malaise, headache and muscle pain, and in some cases, can lead to severe malaria and be fatal.

Unlike other malaria species such as P. falciparumP. vivax also has the ability to lie dormant in the liver from where it may periodically reactivate to cause relapses of P. vivax malaria. A single P. vivax infection may therefore give rise to multiple episodes of malaria, in the absence of a new mosquito bite. These relapses can occur weeks, months or even years after the initial infection. The dormant liver forms of the parasite cannot be treated with most other antimalarial treatments.

Another issue is that the only medicine currently available to stop the relapse is primaquine, a medicine approved in the 1950s, which must be given for 14 days. Given this length of treatment course, many people do not comply with the full course, which results in reduced effectiveness.

The aim of the DETECTIVE study was to look at the effectiveness of treatment in preventing relapse over six months with a 1-day course of tafenoquine, a 14-day course of primaquine, or placebo, with all patients also receiving a 3-day course of chloroquine, a medicine that is used to treat the initial infection.

MedicalResearch.com: What are the main findings?

Response: The DETECTIVE study met its primary endpoint. A significantly greater proportion of patients in the tafenoquine group did not have relapses compared to patients in the placebo group. A similar result was observed for the patients in the primaquine group compared to the placebo group. When considering the compliance issue of primaquine in the real-world setting, we saw that more than 95% of patients in the primaquine group took their treatment as instructed in the setting of a clinical study. From a safety perspective, adverse events from the study were consistent with the known safety profile of tafenoquine.

MedicalResearch.com: What should readers take away from your report?

Response: The positive results of the DETECTIVE study demonstrate the efficacy and safety of tafenoquine in an unprecedented single-dose for relapsing malaria.  These data supported the approval of the medicine by the US Food and Drug Administration and Australia Therapeutic Goods Administration in 2018 marking it as the first new medicine for the radical cure of P. vivax malaria in more than 60 years. Having the data published in the NEJM will help other P. vivax malaria endemic countries as they strive towards malaria elimination. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: The DETECTIVE study was conducted in adult patients with P. vivax malaria and a significant part of the global burden of the disease is in children. GSK and MMV are therefore studying the use of tafenoquine in paediatric patients aged 6 months to 16 years (TEACH study).  In addition, since vivax malaria in Indonesia is frequently resistant to chloroquine, we are conducting another study that is looking at tafenoquine plus dihydroartemisinin–piperaquine as the blood schizonticide (INSPECTOR study) in patients with P. vivax malaria in Indonesia.

Disclosures: The DETECTIVE study was supported by GSK and MMV.

Citation:

Single-Dose Tafenoquine to Prevent Relapse of Plasmodium vivax Malaria
Marcus V.G. Lacerda, M.D., Alejandro Llanos-Cuentas, M.D., Srivicha Krudsood, M.D., Chanthap Lon, M.D., David L. Saunders, M.D., Rezika Mohammed, M.D., Daniel Yilma, M.D., Dhelio Batista Pereira, M.D., Fe E.J. Espino, M.D., Reginaldo Z. Mia, M.D., Raul Chuquiyauri, M.D., Fernando Val, Ph.D., et al.

January 17, 2019
N Engl J Med 2019; 380:215-228
DOI: 10.1056/NEJMoa1710775

Jan 18, 2019 @ 1:24 am 

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The President’s Malaria Initiative Reduced All-Cause Childhood Mortality

MedicalResearch.com Interview with:

Alexsandra Jakubowski

Aleksandra Jakubowski MPH

Aleksandra Jakubowski, MPH PhD candidate
Department of Health Policy and Management
Gillings School of Global Public Health
University of North Carolina at Chapel Hill

MedicalResearch.com: What is the background for this study?

Response: The US President’s Malaria Initiative (PMI) provides approximately $600 million annually to fund implementation of key evidence-based malaria prevention and treatment interventions, including insecticide treated nets (ITNs), artemisinin-based combination therapy (ACT), and indoor residual spraying (IRS) to populations in 19 recipient countries in sub-Saharan Africa (SSA). Despite this considerable investment, no study to date has evaluated the impact of PMI on population health outcomes. Previous evaluations have noted improved health outcomes in PMI countries, but comparison groups are needed to establish whether these changes were beyond the declining trends in mortality observed in the rest of the region. Our study sought to generate objective evidence for policy makers about the role this US-funded malaria aid program may have played in curbing child mortality in SSA.

We used a quasi-experimental design known as difference-in-differences to compare trends in health outcomes in PMI-recipient vs. PMI non-recipient countries. We analyzed publicly-available data from 32 countries in SSA spanning a period that included about ten years before and after the introduction of the program.

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Promising New Drug Can Stop Malaria After Mosquito Bite

MedicalResearch.com Interview with:

Dr Mihály Sulyok MD Eberhard Karls University Institute of Tropical Medicine, Tübingen, Germany

Dr Mihály Sulyok

Dr Mihály Sulyok MD
Eberhard Karls University
Institute of Tropical Medicine,
Tübingen, Germany

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: New antimalarials are desperately needed, not just for treatment, but also for prophylaxis. DSM265, a novel antimalarial compound that selectively inhibits the plasmodial dihydroorotate dehydrogenase has a promising pharmacokinetic profile characterized by a long elimination half-life.

We performed a study at the Institute of Tropical Medicine, Eberhard Karls University (Tübingen, Germany) to investigate safety, tolerability and efficacy of DSM265 using controlled human malaria infection. In the first cohort, 400mg of DSM265 was administered orally to five healthy, malaria naive individuals one day before direct venous inoculation of an established infective dose of P. falciparum sporozoites (PfSPZ Challenge). Placebo was administered to two volunteers. The study was randomized and double blinded. In this cohort all placebo participants developed malaria, whereas all DSM265 participants were protected.

In a second cohort, 400mg DSM265 was administered 7 days before the sporozoite inoculation for six participants, two participants recieved placebo. In this cohort, the two placebo and three of six DSM265 volunteers developed thick blood smear positive malaria. The remaining three DSM265 volunteers developed transient submicroscopic parasitemia without symptoms or thick blood smear positivity. The only possible DSM265-related adverse event was a slight transient elevation in serum bilirubin in one volunteer.

The study was funded by the Global Health Innovative Technology Fund, Wellcome Trust, Bill & Melinda Gates Foundation through Medicines for Malaria Venture, and the German Center for Infection Research.

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Detailed Map of Malaria Mortality Offers Hope of Better Prevention and Control

MedicalResearch.com Interview with:

Simon I. Hay, BSc, DPhil, DSc Professor of Global Health University of Washington Director of Geospatial Science Institute for Health Metrics and Evaluation (IHME).

Prof. Simon Hay

Simon I. Hay, BSc, DPhil, DSc
Professor of Global Health
University of Washington
Director of Geospatial Science
Institute for Health Metrics and Evaluation (IHME).

MedicalResearch.com: Why did you undertake this study?

Response: As malaria control has not been routinely informed by subnational variation of malaria burden, we undertook the study to highlight the potential for high-resolution maps of disease burden to better understand the epidemiology of malaria as well as the contribution of recent control efforts as well as to better inform future malaria control efforts.

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This Generation of Malaria Vaccine Not Perfect But Can Still Save Lives

MedicalResearch.com Interview with:

Philip Bejon, Ph.D. Professor of Tropical Medicine, Director of the Wellcome-KEMRI-Oxford Collaborative Research Programme, Group Head / PI, Consultant Physician and Unit Director Kilifi, Kenya

Dr. Philip Bejon

Philip Bejon, Ph.D.
Professor of Tropical Medicine, Director of the Wellcome-KEMRI-Oxford Collaborative Research Programme, Group Head / PI, Consultant Physician and Unit Director
Kilifi, Kenya

MedicalResearch.com: What is the background for this study?

Response: According to the latest World Health Organisation (WHO) estimates more than 400,000 people died from malaria in 2015, with over 90% of these deaths occurring in sub-Saharan Africa. The vast majority who die are children under 5, and almost all cases are caused by the P. falciparum strain of malaria transmitted by female Anopheles mosquitoes.

RTS,S, which protects only against P. falciparum, was developed by GlaxoSmithKline with support from the PATH Malaria Vaccine Initiative (MVI) and with grant funds from the Bill & Melinda Gates Foundation to MVI. In July 2015, it received a positive opinion from the European Medicines Agency.

Earlier this year, the WHO recommended further evaluation of the four-dose regimen of RTS,S in a pilot implementation programme in sub-Saharan Africa, to address several knowledge gaps before the vaccine might be rolled out more widely.

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Drop in Immunity To Malaria Can Mean More Serious Infections in Pregnancy

Alfredo Mayor Aparicio PhD Associate Research Professor Barcelona Institute for Global HealthMedicalResearch.com Interview with:
Alfredo Mayor Aparicio PhD

Associate Research Professor
Barcelona Institute for Global Health

Medical Research: What is the background for this study? What are the main findings?

Dr. Mayor: The malaria parasite is a well-adapted pathogen which can persist and reappear in areas where infection is no longer circulating or at very low levels. Prevention of such reinfections and resurgences is critical for the current goal of malaria eradication. However, little is known about the determinants and consequences of malaria declines and resurgences. For this reason, understanding the relationship between malaria transmission, immunity and disease burdens is essential to rationalise malaria interventions aimed at reducing host-parasite encounters. We have described changes in prevalence among pregnant women delivering between 2003 and 2012 at antenatal clinics in Southern Mozambique, and showed that a reduction of malaria-specific immunity associated with drops in transmission is accompanied with an increase the severity of malaria infection among those women becoming infected. These results suggest that success of control and elimination activities may lead through a transitional period where infrequent infections will likely slowdown the rate of acquisition of host defenses and will be thus associated with more deleterious effects during pregnancy, thus requiring more precise diagnosis and surveillance methods, as well as improved prevention.

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Benefits of Iron Supplementation During Pregnancy Outweighed Malaria Risks

Dr. Martin N. Mwangi Researcher Division of Human Nutrition, Nutrition and Health over the lifecourse International Nutrition Unit Wageningen University The Netherlands


MedicalResearch.com Interview with:
Dr. Martin N. Mwangi
Researcher
Division of Human Nutrition,
Nutrition and Health over the lifecourse
International Nutrition Unit
Wageningen University
The Netherlands

 

Medical Research: What is the background for this study?

Dr. Mwangi : Anemia in pregnancy is a moderate or severe health problem in more than 80 percent of countries worldwide, but particularly in Africa, where it affects 57 percent of pregnant women. Iron deficiency is the most common cause, but iron supplementation during pregnancy has uncertain health benefits. There is some evidence to suggest that iron supplementation may increase the risk of infectious diseases, including malaria.

Our main objective was to measure the effect of antenatal iron supplementation on maternal Plasmodium infection risk, maternal iron status, and neonatal outcomes. We randomly assigned 470 pregnant Kenyan women living in a malaria endemic area to daily supplementation with 60 mg of iron (n = 237 women) or placebo (n = 233) until 1 month postpartum. All women received 5.7 mg iron/day through flour fortification during intervention and usual intermittent preventive treatment against malaria.

Medical Research: What are the main findings?

Dr. Mwangi : Overall, we found no effect of daily iron supplementation during pregnancy on risk of maternal Plasmodium infection. Iron supplementation resulted in an increased birth weight [5.3 ounces], gestational duration, and neonatal length; enhanced maternal and infant iron stores at 1 month after birth; and a decreased risk of low birth weight (by 58 percent) and prematurity. The effect on birth weight was influenced by initial maternal iron status. Correction of maternal iron deficiency led to an increase in birth weight by [8.4 ounces].

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Red Blood Cell Surface Molecule May Be Target For New Malaria Vaccine and Treatment

Manoj Duraisingh Ph.D. John LaPorte Given Professor of Immunology and Infectious Diseases Harvard T.H. Chan School of Public Health Department of Immunology and Infectious DiseasesBoston, MassachusettsMedicalResearch.com Interview with:
Manoj Duraisingh Ph.D.
John LaPorte Given Professor of Immunology and Infectious Diseases
Harvard T.H. Chan School of Public Health
Department of Immunology and Infectious Diseases
Boston, Massachusetts


MedicalResearch: What is the background for this study? What are the main findings?

Dr. Duraisingh: The malaria parasite P. falciparum is one of the most important pathogens of humans, with enormous mortality resulting from blood-stage infections, when parasites replicate exponentially in red blood cells. Although anti-Plasmodial drugs are in clinical use, widespread and increasing parasite drug-resistance has contributed to an ongoing public health crisis, and we urgently need to find novel approaches to prevent and treat disease.

Targeting host red blood cell molecules presents an unexploited alternative. However, the highly differentiated and enucleated red blood cell poses a significant technical hurdle for genetic experimentation, due to the lack of a nucleus.

Here we have developed a novel, forward genetic screen to identify critical factors of malaria infection of red blood cells in an unbiased fashion. Our screen takes advantage of recent advances in human stem cell biology that enable the ex vivo culture of red blood cells from nucleated hematopoietic precursors which are amenable to in vitro genetics.

We have now identified a surface molecule CD55 (alias Decay-Accelerating Factor, DAF) as an essential host factor required for the invasion of red blood cells by P. falciparum. We demonstrate that this protein is required by all P. falciparum strains tested (laboratory and field) for invasion. Furthermore, we demonstrate that CD55 acts at the initial stage of invasion when the P. falciparum parasite attaches to the surface of the red blood cell.

Collectively, our findings indicate that CD55 is an ideal target for the development of new host-directed and vaccine therapeutics for malaria.

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Viagra Derivatives May Block Malaria Transmission

MedicalResearch.com Interview with:
Dr. Gordon Langsley
Laboratoire de Biologie Cellulaire Comparative des Apicomplexes,
Institut Cochin, INSERM U1016, CNRS UMR 8104,
Faculté de Medecine
Université Paris Descartes, Paris

Medical Research: What is the background for this study? What are the main findings?

Response: We have been studying the role of cAMP-dependent PKA signaling in Plasmodium falciparum-infected red blood cells for some time; see just a few examples: PMID: 25522250; PMID: 22626931; PMID: 18248092; PMID: 11559352 and we came to the conclusion that intra cellular cAMP levels regulate infected red blood cell deformability and adhesion to for example, brain endothelial cells.

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Malaria Vaccine Has Potential To Contribute To Disease Control

Mary J Hamel, M.D. Chief, Strategic and Applied Sciences Unit, And Deputy Branch Chief for Science, CDC Malaria Branch US Centers for Disease Control and Prevention 1600 Clifton Rd, NE, MS A06 Atlanta GA 30333MedicalResearch.com Interview with:
Mary J Hamel, M.D.
Chief, Strategic and Applied Sciences Unit,
And Deputy Branch Chief for Science, CDC Malaria Branch
US Centers for Disease Control and Prevention
1600 Clifton Rd, NE, MS A06
Atlanta GA 30333
Dr. Hamel was principal investigator at the Siaya site in western Kenya.

Medical Research: What is the background for this study? What are the main findings?

Dr. Hamel: Major progress has been made in malaria control during the past decade with the scale up of proven interventions including insecticide treated nets (ITNs), indoor residual spraying, effective diagnosis and treatment for malaria, and intermittent preventive treatment of malaria in pregnancy. Nonetheless, malaria remains a major cause of morbidity and mortality, and a leading cause of pediatric death worldwide. An estimated 198 million cases of malaria and 580,000 deaths occurred in 2013 – most of these in African children.

Now we face additional challenges in malaria control – the emergence of insecticide and drug resistance threatens some of our most effective interventions. New tools are needed to reach the goal of malaria elimination and eventual eradication. Vaccines are some of our most cost-effective interventions, and an effective malaria vaccine would be an important addition to our current malaria control tools.

This week, the RTS,S Clinical Trials Partnership published the final vaccine efficacy and safety results from the RTS,S/AS01 malaria vaccine phase 3 trial in the Lancet (Efficacy and safety of RTS,S/AS01 malaria vaccine with or without a booster dose in infants and children in Africa: final results of a phase 3, individually randomised, controlled trial, http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60721-8/abstract). This large randomized controlled double-blind phase 3 clinical trial was conducted in 11 sites in 7 African countries across a range of malaria transmission levels. In all, 15,460 children and young infants were enrolled in two age-categories, those first vaccinated at 5-17 months of age (referred to as children), and those first vaccinated at 6-12 weeks of age (referred to as young infants) who received the RTS,S/AS01 vaccine along with their routine childhood immunizations. Participants were randomized into 3 groups – the first group received three doses of the RTS,S/AS01 vaccine followed 18 months later by a booster dose; the second group received three doses of the RTS,S/AS01 vaccine without a booster; and the third group received a comparator vaccine. All participants received an ITN. Children were followed for an average of 48 months and infants for an average of 38 months.

We found that vaccine efficacy was modest. Vaccine efficacy against clinical malaria in children was 36% with a booster and 28% without, and vaccine efficacy against severe malaria was 32% with a booster and non-significant without.   Efficacy results in young infants were lower than those in children– vaccine efficacy against clinical malaria was 36% with a booster and 28% without, and vaccine efficacy against severe malaria was non-significant.

However, impact, defined as the number of cases averted per 1000 participants vaccinated, was substantial in both age-categories, and highest where malaria burden was greatest. In children who received the booster, during 4 years follow-up, 1700 cases of clinical malaria were averted per 1000 children vaccinated. In young infants, during 3 years follow-up, nearly 1000 cases were averted per 1000 young infants vaccinated.

The safety findings were comparable overall in the different study arms, but two safety findings are notable. Meningitis occurred more frequently among children (but not young infants) who received RTS,S/AS01 than among those who received the comparator vaccines. There was no relationship between when the vaccine was administered and when meningitis occurred, most cases occurred in only two study sites, and the finding may be due to chance. If RTS,S/AS01 is licensed, post-licensing studies will be done to establish the significance of this finding. Both children and young infants experienced more episodes of fever and associated febrile convulsions during the 7 days following vaccination; convulsions occurred in 2.2 – 2.5/1000 vaccine doses. Continue reading

Biomarkers May Lead to Breath Test For Malaria

Wikipedia mosquitoMedicalResearch.com Interview with:
Amalia Z. Berna

CSIRO Food and Nutrition Flagship
Acton ACT 2601

MedicalResearch: What is the background for this study? What are the main findings?

Response: Globally an estimated 3.2 billion people in 97 countries are at risk of malaria and, in 2013, an estimated 198 million cases and 584,000 deaths were attributed to this infection. Accurate diagnosis of malaria is important to provide adequate treatment, conserve valuable drugs, and help prevent the emergence of resistant strains of the parasite. It is becoming important to be able to diagnose low level and asymptomatic cases, to support the drive towards local and/or global eradication.

Detection of volatile chemicals in expired breath has been used to diagnose or monitor a small number of diseases, including Helicobacter pylori infection, diabetes and lung inflammation but, if breath analysis is to be more broadly useful, we need to identify reliable biomarkers for a wider range of diseases and to develop more robust methods for breath analysis.

In collaboration with Professor James McCarthy of the QIMR Berghofer Institute and Associate Professor Kevin Saliba of the ANU, we found:

  1. Four specific thioether biomarkers in the breath of volunteers with experimentally induced blood stage Plasmodium falciparum
  2. That the levels of the volatiles strongly correlate with the levels of malaria parasitaemia.
  3. That the thioethers are not produced by in vitro cultures of falciparum.
  4. That although we do not know the metabolic origin of the thioethers, our results suggest that interplay between host and parasite metabolic pathways is involved in their production.

We think it is important to emphasise that no volunteer was infected with malaria primarily for the purpose of this study. Our research was entirely piggy-backed on pre-existing trials of malaria therapeutics.

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Detecting Infectious Disease Without Needles, Through Skin Patch

Dr. Simon Corrie PhD The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Delivery of Drugs and Genes Group Australian Infectious Diseases Research Centre, St. Lucia, Queensland, AustraliaMedicalResearch.com: Interview with:
Dr. Simon Corrie PhD
The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Delivery of Drugs and Genes Group
Australian Infectious Diseases Research Centre, St. Lucia, Queensland, Australia

Medical Research: What is the background for this study? What are the main findings?

Dr. Corrie: P. falciparum malaria is a major cause of morbidity and mortality around the world, particularly in developing countries. Some estimates also suggest that in developing countries, children under 5 account for ~90% mortality. As malaria is treatable, positive detection is important rule out other causes, avoid over-treatment leading to resistance, and to guide appropriate treatment. Our focus is on developing diagnostic devices for infectious diseases, which do not require needles, lancets or laboratory processing.

These devices are “microprojection arrays”, silicon chips that can be applied to the skin to capture circulating protein biomarkers in the interstitial fluid of the skin. In this publication we:
(a) developed methods to improve the sensitivity of the devices for capturing HRP2,
(b) confirmed that HRP2 protein injected intravenously is detectable in skin fluid and
(c) showed that we could capture both HRP2 and total IgG (as a positive control for penetration into skin) at the same time.

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