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Malaria drug treatment breakthrough

April 6, 2013 1 comment

An international study, involving researchers from Griffith University’s Eskitis Institute, has discovered a molecule which could form the basis of powerful new anti-malaria drugs.

Professor Vicky Avery from Griffith University’s Eskitis Institute is co-author of the paper “Quinolone-3-Diarylethers: a new class of drugs for a new era of malaria eradication” which has been published in the journal Science Translational Medicine.

“The 4(1H)-quinolone-3- diarylethers are selective potent inhibitors of the parasite mitochondrial cytochrome bc1 complex,” Professor Avery said.

“These compounds are highly active against the types of malaria parasites which infect humans, Plasmodium falciparum and Plasmodium vivax,” she said.

“What is really exciting about this study is that a new class of drugs based on the 4(1H)- quinolone-3- diarylethers would target the malaria parasite at different stages of its lifecycle.”

This provides the potential to not only kill the parasite in people who are infected, thus treating the clinical symptoms of the disease, but also to reduce transmission rates.

“Just one of these properties would be of great benefit but to achieve both would really make a difference in reducing the disease burden on developing nations,” Professor Avery said.

“There is also the real possibility that we could begin to impact on the incidence and spread of malaria, bringing us closer to the ultimate goal of wiping out malaria altogether.”

The selected preclinical candidate compound, ELQ-300, has been demonstrated to be very effective at blocking transmission in the mouse models.

There is a further benefit in that the predicted dosage in patients would be very low and it’s expected that ELQ-300, which has a long half-life, would provide significant protection.

The development of a new chemical class of anti-malarial drugs is very timely as the parasite is becoming increasing resistant to currently available treatments.

Eskitis Director Professor Ronald J Quinn AM said “I congratulate Professor Avery on her contribution to the discovery of this new class of anti-malarials. This is an exciting discovery that closely aligns with the Institute’s focus on global health and fighting diseases that burden the developing world. We are continuing to take the fight to malaria along a number of fronts, including targeting its many life cycle stages.”

Journal reference: Science Translational Medicine

A. Nilsen, A. N. LaCrue, K. L. White, I. P. Forquer, R. M. Cross, J. Marfurt, M. W. Mather, M. J. Delves, D. M. Shackleford, F. E. Saenz, J. M. Morrisey, J. Steuten, T. Mutka, Y. Li, G. Wirjanata, E. Ryan, S. Duffy, J. X. Kelly, B. F. Sebayang, A.-M. Zeeman, R. Noviyanti, R. E. Sinden, C. H. Kocken, R. N. Price, V. M. Avery, I. Angulo-Barturen, M. B. Jiménez-Díaz, S. Ferrer, E. Herreros, L. M. Sanz, F.-J. Gamo, I. Bathurst, J. N. Burrows, P. Siegl, R. K. Guy, R. W. Winter, A. B. Vaidya, S. A. Charman, D. E. Kyle, R. Manetsch, M. K. Riscoe, Quinolone-3-Diarylethers: A New Class of Antimalarial Drug. Sci. Transl. Med. 5, 177ra37 (2013).

Provided by: Griffith University

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Breakthrough in Malaria Treatment in the Run Up to World Malaria Day

April 21, 2011 Leave a comment

Ahead of World Malaria Day (25 April), EU-funded researchers have discovered that drugs originally designed to inhibit the growth of cancer cells can also kill the parasite that causes malaria. They believe this discovery could open up a new strategy for combating this deadly disease, which, according to World Health Organisation statistics, infected around 225 million and killed nearly 800,000 people worldwide in 2009.

Efforts to find a treatment have so far been hampered by the parasite’s ability to quickly develop drug resistance. The research involved four projects funded by the EU (ANTIMAL, BIOMALPAR, MALSIG and EVIMALAR) and was led by laboratories in the UK, France and Switzerland with partners from Belgium, Germany, Denmark, Greece, Spain, Italy, Netherlands, Portugal, and Sweden, along with many developing nations severely affected by malaria.

Research, Innovation and Science Commissioner Máire Geoghegan-Quinn said: “This discovery could lead to an effective anti-malaria treatment that would save millions of lives and transform countless others. This demonstrates yet again the added value both of EU-funded research and innovation in general and of collaboration with researchers in developing countries in particular. The ultimate goal is the complete eradication of the global scourge of malaria and collaborative work across many borders is the only way of confronting such global challenges effectively.”

Cancer drugs to kill malaria parasite

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites reproduce in the liver, and then infect and multiply in red blood cells. Joint research led by EU-funded laboratories at the Inserm-EPFL Joint Laboratory, Lausanne, (Switzerland/France), Wellcome Trust Centre for Molecular parasitology, University of Glasgow (Scotland), and Bern University (Switzerland) showed that, in order to proliferate, the malaria parasite depends upon a signalling pathway present in the host’s liver cells and in red blood cells. They demonstrated that the parasite hijacks the kinases (enzymes) that are active in human cells, to serve its own purposes. When the research team used cancer chemotherapy drugs called kinase inhibitors to treat red blood cells infected with malaria , the parasite was stopped in its tracks.

A new strategy opens up

Until now the malaria parasite has managed to avoid control by rapidly developing drug resistance through mutations and hiding from the immune system inside liver and red blood cells in the body of the host, where it proliferates. The discovery that the parasite needs to hijack some enzymes from the cell it lives in opens up a whole new strategy for fighting the disease. Instead of targeting the parasite itself, the idea is to make the host cell environment useless to it, by blocking the kinases in the cell. This strategy deprives the parasite of a major modus operandi for development of drug resistance.

Several kinase-inhibiting chemotherapy drugs are already used clinically in cancer therapy, and many more have already passed phase-I and phase II clinical trials. Even though these drugs have toxic side-effects, they are still being used over extended periods for cancer treatment. In the case of malaria, which would require a shorter treatment period, the problem of toxicity would be less acute. Researchers are proposing therefore that these drugs should be evaluated immediately for anti-malarial properties, drastically reducing the time and cost required to put this new malaria-fighting strategy into practice.

The next steps will include mobilising public and industrial partners to verify the efficacy of kinase inhibitors in malaria patients and to adjust the dose through clinical trials, before the new treatments can be authorised and made available to malaria patients worldwide.

Journal Reference:

  1. Audrey Sicard, Jean-Philippe Semblat, Caroline Doerig, Romain Hamelin, Marc Moniatte, Dominique Dorin-Semblat, Julie A. Spicer, Anubhav Srivastava, Silke Retzlaff, Volker Heussler, Andrew P. Waters, Christian Doerig. Activation of a PAK-MEK signalling pathway in malaria parasite-infected erythrocytesCellular Microbiology, 2011; DOI:10.1111/j.1462-5822.2011.01582.x
  2. The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by European Commission, Research & Innovation DG, viaAlphaGalileo.