Alternatives to currently used antimalarial drugs: in search of a magic bullet

Abstract

Malaria is a major cause of morbidity and mortality in many African countries and parts of Asia and South America. Novel approaches to combating the disease have emerged in recent years and several drug candidates are now being tested clinically. However, it is long before these novel drugs can hit the market, especially due to a scarcity of safety and efficacy data.To reduce the malaria burden, the Medicines for Malaria Venture (MMV) was established in 1999 to develop novel medicines through industry and academic partners’ collaboration. However, no reviews were focused following various preclinical and clinical studies published since the MMV initiation (2000) to till date.We identify promising approaches in the global portfolio of antimalarial medicines, and highlight challenges and patient specific concerns of these novel molecules. We discuss different clinical studies focusing on the evaluation of novel drugs against malaria in different human trials over the past five years.The drugs KAE609 and DDD107498 are still being evaluated in Phase I trials and preclinical developmental studies. Both the safety and efficacy of novel compounds such as KAF156 and DSM265 need to be assessed further, especially for use in pregnant women. Synthetic non-artemisinin ozonides such as OZ277 raised concerns in terms of its insufficient efficacy against high parasitic loads. Aminoquinoline-based scaffolds such as ferroquine are promising but should be combined with good partner drugs for enhanced efficacy. AQ-13 induced electrocardiac events, which led to prolonged QTc intervals. Tafenoquine, the only new anti-relapse scaffold for patients with a glucose-6-phosphate dehydrogenase deficiency, has raised significant concerns due to its hemolytic activity. Other compounds, including methylene blue (potential transmission blocker) and fosmidomycin (DXP reductoisomerase inhibitor), are available but cannot be used in children.At this stage, we are unable to identify a single magic bullet against malaria. Future studies should focus on effective single-dose molecules that can act against all stages of malaria in order to prevent transmission. Newer medicines have also raised concerns in terms of efficacy and safety. Overall, more evidence is needed to effectively reduce the current malaria burden. Treatment strategies that target the blood stage with transmission-blocking properties are needed to prevent future drug resistance.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0196-8) contains supplementary material, which is available to authorized users.

The Toxoplasma Centrocone Houses Cell Cycle Regulatory Factors

“…Highly efficient asexual replication is fundamental to the ability of apicomplexan parasites to spread infections in their hosts, and this is evident by the fact that the actions of the best drugs used to combat these infections all reduce or block parasite proliferation. Unfortunately, existing therapies, particularly against malaria ( 1 ), are under constant pressure from acquired parasite drug resistance, and new treatments are continually needed. The peculiar proliferative cell cycles of Apicomplexa parasites differ substantially from the hosts they inhabit, and it seems safe to predict that a better understanding of the molecular basis of parasite cell division could yield new drug targets.…”

TheToxoplasmacentrocone houses cell cycle regulatory factors

“…Highly efficient asexual replication is fundamental to the ability of apicomplexan parasites to spread infections in their hosts and this is evident by the action of drugs used to combat these infections as the best treatments all reduce or block parasite proliferation. Unfortunately, existing therapies, particularly against malaria (1), are under constant pressure from acquired parasite drug resistance requiring a continuing search for new treatments. The peculiar proliferative cell cycles of Apicomplexa parasites differ substantially from the hosts they inhabit and it seems safe to predict that a better understanding of the molecular basis of parasite cell division could yield new drug targets.…”

In Vivo Antimalarial Activity of the Solvent Fractions of Fruit Rind and Root of Carica papaya Linn (Caricaceae) against Plasmodium berghei in Mice

“…Antimalarial drug resistance remains a major challenge and continued to emerge creating an obstacle in malaria control and elimination [ 5 , 28 ]. At present, developing novel approaches and new alternative antimalarial drugs is pivotal to combat the disease [ 29 ]. From history, medicinal plants are endowed with active antimalarial compounds as artemisinin is obtained from Artemisia annua and quinine from Cinchona bark [ 30 ].…”