CompletedEarly Phase 1ACTRN12614000228684

A safety and tolerability study in humans for chemically attenuated malaria parasites

A safety and tolerability study in humans for P. falciparum 7G8 blood stage parasites attenuated with different doses of Tafuramycin-A


Sponsor

Griffith University

Enrollment

9 participants

Start Date

Jun 30, 2014

Study Type

Interventional

Conditions

Summary

This study is examining the safety, tolerability, persistence and immunogenicity of chemically attenuated P. falciparum 7G8 infected red blood cells. Participants will receive a single inoculum of malaria parasites attenuated with either 50nM, 100nM or 200nM of Tafuramycin-A. Following administration of the inoculum, we will measure the level of malaria parasites in the blood-stream and then administer anti-malarial treatment (Riamet) at D28. We will also be assessing the safety of the inoculum and the way the immune system responds to it. Determining the safety, persistence and immunogenicity of the Tafuramycin-A malaria parasites is important as they form the basis of a novel malaria vaccine approach.


Eligibility

Sex: MalesMin Age: 18 YearssMax Age: 60 Yearss

Inclusion Criteria6

  • Volunteers will be males, aged 18-60 years of age who do not live alone for the duration of the study.
  • Volunteers must have a BMI within the range of 18-30.
  • Volunteers must understand the procedures involved and agree to participate in the study by giving fully informed, written consent.
  • Be contactable and available for the duration of their study schedule (maximum of 3 months)
  • Volunteers must be non-smokers and in good health, as assessed during pre-study medical examination and by review of screening results
  • Good peripheral venous access

Exclusion Criteria29

  • Has increased cardiovascular disease risk (defined as >10%, 5 yr risk) as determined by the method of Gaziano et al. Risk factors include: sex, age, systolic blood pressure, smoking status, body mass index (BMI, kg/mm2), and reported diabetes status and blood pressure.
  • History of splenectomy
  • History of severe allergic reaction, anaphylaxis or convulsion following any vaccination, infusion or treatment with anti-malarial drugs artemether and/or lumefantrine.
  • Presence of current or suspected chronic diseases such as cardiac or autoimmune disease (HIV or other immunodeficiencies), insulin dependent diabetes, progressive neurological disease, severe malnutrition, acute or progressive hepatic disease, acute or progressive renal disease, psoriasis, rheumatoid arthritis, asthma, epilepsy, obsessive compulsive disorder, skin carcinoma excluding non-spreadable skin cancers such as basal cell and squamous cell carcinoma.
  • Known inherited genetic anomaly (known as cytogenic disorders) eg Down’s syndrome.
  • Individuals wishing to donate blood to the Australian Red Cross Blood Service in the future.
  • The volunteer has a diagnosis of schizophrenia, bi-polar disease, severe depression or other severe (disabling) chronic psychiatric disorder. Participants who are receiving a single anti-depressant drug and are stable for at least 3 months prior to enrollment without decompensating may be allowed to enroll in the study at the investigator’s discretion.
  • Has been hospitalised in the past 5 years prior to enrolment for psychiatric illness, history of suicide attempt or confinement for danger to self or others.
  • Known pre-existing prolongation of the QTc interval. Family history of congenital prolongation of the QTc interval on electrocardiograms or of sudden death or any other clinical conditions known to prolong the QTc interval eg volunteers with a history of symptomatic cardiac arrhythmias, with clinically relevant bradycardia or with severe cardiac disease.
  • Recent or current therapy with antibiotic or drug with potential antimalarial activity (tetracycline, azithromycin, clindamycin, hydroxychloroquine etc).
  • Concomitant use of any drug which is metabolized by the cytochrome enzyme CYP2D6 (eg flecainide, metoprolol, imipramine, amitriptyline, clomipramine) OR drugs that are known to prolong the QTc interval e.g. antiarrhythmics of classes IA and III, neuroleptics, antidepressant agents, certain antibiotics (including some agents of the following classes: macrolides, fluoroquinolones, imidazole and triazole antifungal agents), certain nonsedating antihistamines (terfenadine, astemizole), cisapride.
  • Use of corticosteroids, anti-inflammatory drugs, any immunomodulators or anticoagulants. Currently receiving or have previously received immunosuppressive therapy, including systemic steroids including ACTH or inhaled steroids in dosages which are associated with hypothalamic-pituitary axis suppression such as 1mg/kg/day or prednisone or its equivalent or chronic use of inhaled high potency corticosteroids (budesonide 800 microgram per day or fluticasone 750 microgram).
  • Presence of acute infectious disease or fever (e.g. sub-lingual temperature greater than or equal to 38.5oC) within the five days prior to the study product administration.
  • Evidence of acute illness within the 4 weeks before trial prior to screening and enrollment.
  • Significant intercurrent disease of any type, in particular liver, renal, cardiac, pulmonary, neurologic, rheumatologic or autoimmune disease by history, physical examination and/or laboratory studies including urinalysis.
  • Alcohol consumption greater than community norms (ie more than 21 standard drinks per week for males).
  • A history of drug habituation, or any prior intravenous usage of an illicit substance.
  • Medical requirement for intravenous administration of immunoglobulin or blood transfusions.
  • Participation in any investigational product study within 8 weeks preceding the study.
  • Participation in any research study involving significant blood sampling, or blood donation to Red Cross (or other) blood bank during the 8 weeks preceding the study.
  • Have ever received a blood transfusion.
  • Positive test for HIV, Hepatitis B, Hepatitis C, Human T-cell Lymphotropic Virus I and II(HTLV I and II), TB or syphilis.
  • Any clinically significant biochemical or haematologic abnormality (Hb must be greater than or equal to 13.5g/dL).
  • Ingestion of any poppy seeds within the 48 hours prior to the screening blood test (volunteers will be advised by phone not to consume any poppy seeds in this time period).
  • Detection of any of the following drugs ( Amphetamines, Methamphetamines, Barbiturates, Benzodiazepines, Cocaine, Methadone, Opiates, Phencyclidine, Tetrahydrocannabinols, Tricyclic antidepressants) in the urine drug screen unless there is an explanation acceptable to the medical investigator (eg the subject has stated in advance that they consumed a prescription or OTC product which contained the detected drug) and/or the subject has a negative drug screen on retest by the pathology laboratory.
  • Evidence of any condition that, in the opinion of the clinical investigator, might interfere with the evaluation of the study objectives or pose excessive risks to participants
  • G-6-PD deficiency
  • History of malaria
  • Travelled to or lived ( greater than 2 weeks) in a malaria-endemic country during the past 12 months or planned to travel to a malaria-endemic country during the course of the study.

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Interventions

Volunteers will be inoculated on Day 0 of the study with human red blood cells infected with Plasmodium falciparum 7G8 and attenuated with Tafuramycin-A. Three different groups will be compared. Gr

Volunteers will be inoculated on Day 0 of the study with human red blood cells infected with Plasmodium falciparum 7G8 and attenuated with Tafuramycin-A. Three different groups will be compared. Group A: 3 x 10^7 Plasmodium falciparum 7G8 infected red blood cells attenuated with 50nM of Tafuramycin-A, administered intravenously Group B: 3 x 10^7 Plasmodium falciparum 7G8 infected red blood cells attenuated with 200nM of Tafuramycin-A, administered intravenously Group C: 3 x 10^7 Plasmodium falciparum 7G8 infected red blood cells attenuated with 200nM of Tafuramycin-A, administered intravenously Duration of inoculum: one dose at day 0. Participants will be actively monitored up to Day 28 post injection and parasite levels in the blood will be monitored during this time period. At Day 28, scheduled anti-malarial drug treatment (Riamet, also known as Artemether-Lumefantrine) will be administered. If however, there is evidence of a developing malaria infection prior to Day 28 (ie indicating attenuation of the parasites was incomplete), then participants will immediately commence anti-malarial treatment with Riamet. Duration and dosage of anti-malarial treatment: Artemether (20mg) and Lumefantrine (120mg): 4 tablets orally as a single dose under direct supervision by clinical staff at the following times: 0, 8hrs, 24hrs, 36hrs, 47hrs and 60hrs making a total dose of 24 tablets in 6 doses.


Locations(1)

QLD, Australia

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