CompletedPhase 2ACTRN12611001203943

Immune response in a human malaria challenge system.

An experimental study to characterize molecular signatures during early Plasmodium falciparum blood stage infection in healthy male volunteers.


Sponsor

Queensland Institute of Medical Research

Enrollment

16 participants

Start Date

Jan 14, 2012

Study Type

Interventional

Conditions

Summary

This is a Phase II clinical trial for the study of the efficacy of antimalarial drugs against Plasmodium falciparum by experimental challenge with a low dose of blood stage parasites in healthy male volunteers. This trial is to be conducted under the Australian Therapeutic Goods Administration (TGA) Clinical Trial Notification Scheme (CTN). The purpose of the study is to compare the gene expression profiles of whole blood and T cell subsets before and after experimental challenge with a low dose of Plasmodium falciparum blood stage parasites; To identify molecular signatures that predict disease outcome, as well as the safety and efficacy of future malaria vaccines and to investigate gametocyte maturation during early blood stage infection.


Eligibility

Sex: MalesMin Age: 18 YearssMax Age: 45 Yearss

Inclusion Criteria6

  • Volunteers will be males, aged between 18 and 45 years who do not live alone (from Day 1 until at least the end of the antimalarial drug treatment).
  • Volunteers must have a BMI within the range 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 the trial (maximum of 4 weeks)
  • 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 Criteria32

  • History of malaria
  • Travelled to or lived (>2 weeks) in a malaria-endemic country during the past 12 months or planned travel to a malaria-endemic country during the course of the study
  • Has evidence of increased cardiovascular disease risk (defined as >10%, 5 year risk) as determined by the method of Gaziano et al., (15). Risk factors include sex, age, systolic blood pressure (mm Hg), smoking status, body mass index (BMI, kg/mm2), reported diabetes status and blood pressure
  • History of splenectomy
  • History of a severe allergic reaction, anaphylaxis or convulsions following any vaccination or infusion.
  • Presence of current or suspected serious 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 or obsessive compulsive disorder, skin carcinoma excluding non spreadable skin cancers such as basal cell and squamous cell carcinoma
  • Known inherited genetic anomaly (known as cytogenetic disorders) e.g., Down’s syndrome
  • Volunteers wishing to be able to donate blood to the ARCBS in the future
  • Presence of retinal or visual field changes either attributable to 4-aminoquinoline compounds or to any other etiology
  • The volunteer has a diagnosis of schizophrenia, bi-polar disease, or other severe (disabling) chronic psychiatric diagnosis
  • The volunteer has been hospitalized within the past 5 years prior to enrollment for psychiatric illness, history of suicide attempt or confinement for danger to self or others
  • The volunteer is receiving psychiatric drugs. Participants who are receiving a single antidepressant 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.
  • 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 condition known to prolong the QTc interval, e.g. volunteers with a history of symptomatic cardiac arrhythmias, with clinically relevant bradycardia or with severe cardiac disease
  • Recent or current therapy with an antibiotic or drug with potential antimalarial activity (tetracycline, azthromycin, clindamycin, hydroxychloroquine etc.)
  • Known hypersensitivity to sulfa drugs
  • Concomitant use of any drug which is metabolised by the cytochrome enzyme CYP2D6 (e.g. 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-adrenal axis suppression such as 1mg/kg/day of prednisone or its equivalent or chronic use of inhaled high potency corticosteroids (budesonide 800 µg per day or fluticasone 750 µg)
  • Presence of acute infectious disease or fever (e.g., sub-lingual temperature ? 38.5°C) within the five days prior to study product administration)
  • Evidence of acute illness within the four weeks before trial prior to screening
  • 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 (i.e. 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 immunoglobulin or blood transfusions
  • Participation in any investigational product study within the 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 reference drug dose in the study
  • Have ever received a blood transfusion
  • Positive test for HIV, Hepatitis B, hepatitis C, Human T-cell Lymphotropic Virus I & II (HTLVI & HTLVII), and syphilis
  • Any clinically significant biochemical or haematologic abnormality (Hb must be =13.5g/dL)
  • Ingestion of any poppy seeds within the 24 hours prior to the screening blood test (volunteers will be advised by phone not to consume any poppy seed in this time period)
  • Detection of any drug listed Appendix 2 in the urine drug screen unless there is an explanation acceptable to the medical investigator (e.g. 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 urine 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.

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Interventions

This is a single-centre, controlled study using a Blood Stage Plasmodium Falciparum Challenge (BSPC) inoculum challenge to characterize molecular signatures during early Plasmodium falciparum blood st

This is a single-centre, controlled study using a Blood Stage Plasmodium Falciparum Challenge (BSPC) inoculum challenge to characterize molecular signatures during early Plasmodium falciparum blood stage infection The study will be conducted in 2 or more cohorts (n equal to 8 and n equal 8). Cohort 2 will not commence until at least after day 13 of the previous cohort and review by Safety Review Team following day 10 exit of the previous cohort. Each participant in the cohort will be inoculated on Day 0 with approximately 450 Plasmodium falciparum-infected human erythrocytes administered intravenously. On an outpatient basis, participants will be monitored daily (AM) or morning (AM) and evening (PM) (once PCR positive for presence of malaria parasites) from day 1 to day 9 for adverse events and the unexpected early onset of symptoms, signs or parasitological evidence of malaria. On the day designated for commencement of treatment, as determined by qPCR results, participants will be admitted to the study unit and confined for safety monitoring and antimalarial treatment. The threshold for commencement of treatment will be when PCR quantification is confirmed to be greater than or equal to 1,000 parasites/mL when the participants will be administered antimalarial treatment. If clinical or parasitological evidence of malaria (either the identification of two or more malaria parasites on a malaria thick film, platelet count less than 100 x109/L, or the onset of clinical features of malaria) occurs or PCR quantification of greater than or equal to 1,000 parasites/mL is detected before day 9 morning, allocated treatment will begin at this time. Following treatment, participants will be followed up as inpatients for at least 36 hours, to ensure tolerance of the therapy and clinical response, then if clinically well on an outpatient basis for safety and continued presence of malaria parasites via PCR and thick blood film review. Adverse events will be monitored via telephone monitoring, within the clinical research unit and on outpatient review after malaria challenge inoculation and antimalarial study drug administration. Blood samples for safety evaluation, malaria monitoring and red blood cell antibodies will be drawn at baseline and at nominated times after malaria challenge.


Locations(1)

Australia

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ACTRN12611001203943


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