Biomarkers of P. Vivax Relapse

2020-01-21 11:32:37 | BioPortfolio


Plasmodium vivax malaria is difficult to manage because even after taking medicine that kills the infection in the blood, it can continue to hide quietly in the liver, later re-emerging into the blood and causing another episode of malaria illness (relapse). This clinical trial aims to enroll patient with P. vivax infections and try to detect signals in blood, urine and/or saliva coming from the silent liver stages to help identify who could benefit from treatment with primaquine. It also will explore if certain factors of patients negatively impact primaquine efficacy.


Plasmodium vivax, the most widely distributed human malaria, has resisted control largely due to a relapsing hypnozoite liver stage that is clinically silent until emergence and replication in the blood weeks to months later. Curative treatment with primaquine is often not achieved due to potential toxicity in those with G6PD deficiency, poor adherence to the two-week course, and ineffective metabolism of primaquine in those with polymorphisms in cytochrome P450 isoenzyme 2D6 (CYP2D6). Identifying those who harbor hypnozoites will allow for judicious use of primaquine in returning travelers/active duty personnel as well as targeted administration to those living in endemic areas to interrupt parasite transmission in the community. The trial will be conducted in patients presenting with uncomplicated P. vivax malaria at clinical trial sites run by Armed Forces Research Institute of Medical Sciences (AFRIMS) in Southeast Asia. It is designed to capture vivax patients who still harbor the dormant liver stage hypnozoites after treatment with a short acting oral blood schizonticide, and subsequently relapse during the follow-up period while staying in in study-provided housing to reduce risk of reinfection and surveilled daily for parasites or clinical signs of relapse. Longitudinal blood and urine sampling will be done to allow for retrospective analysis to identify biomarkers of hypnozoite infection and subsequent relapse using a systems biology approach. A smaller arm will be enrolled and will receive the short-activing schizonticide with primaquine radical cure at time of admission and followed similarly for relapse. All subjects will be followed for a total of 6 months in order to assess effectiveness of primaquine radical cure for P. vivax infections.

Study Design






Khun Han Hospital
Khun Han




Armed Forces Research Institute of Medical Sciences, Thailand

Results (where available)

View Results


Published on BioPortfolio: 2020-01-21T11:32:37-0500

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Medical and Biotech [MESH] Definitions

An aminoquinoline that is given by mouth to produce a radical cure and prevent relapse of vivax and ovale malarias following treatment with a blood schizontocide. It has also been used to prevent transmission of falciparum malaria by those returning to areas where there is a potential for re-introduction of malaria. Adverse effects include anemias and GI disturbances. (From Martindale, The Extra Pharmacopeia, 30th ed, p404)

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Vaccines made from antigens arising from any of the four strains of Plasmodium which cause malaria in humans, or from P. berghei which causes malaria in rodents.

A protozoan parasite that causes vivax malaria (MALARIA, VIVAX). This species is found almost everywhere malaria is endemic and is the only one that has a range extending into the temperate regions.

Malaria caused by PLASMODIUM FALCIPARUM. This is the severest form of malaria and is associated with the highest levels of parasites in the blood. This disease is characterized by irregularly recurring febrile paroxysms that in extreme cases occur with acute cerebral, renal, or gastrointestinal manifestations.

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