This is an open-label, adaptive study that will utilise the P. falciparum induced blood stage malaria (IBSM) model to characterise the pharmacokinetic/pharmacodynamic (PK/PD) profile of pyronaridine. Up to 18 healthy, malaria naïve adult participants are planned to be enrolled into this study, in cohorts of up to six participants each. Following a screening period of up to 28 days, cohorts of up to 6 healthy participants will be enrolled. Each participant will be inoculated intravenously on Day 0 with P. falciparum infected erythrocytes. Participants will be followed up daily on Days 1 to 3, and will attend the clinical unit once on Days 4, 5, 6 and 7 for clinical evaluation and blood sampling. Participants will be admitted to the clinical trial unit on Day 8 for a single oral dose of pyronaridine. Different doses of pyronaridine will be administered across and within cohorts. Participants will be randomised to a dose group on the day of dosing. The highest dose of pyronaridine administered will be no more than 720 mg; the lowest dose administered will be no less than 180 mg. Each subsequent cohort will be composed of up to 3 dose groups. The Safety Data Review Team (SDRT) will review all available safety and tolerability data from the previous cohort/s prior to inoculation of the next cohort. Participants will be confined in the clinical unit for at least 96 h (Days 8 - 12) to monitor the safety and tolerability of pyronaridine dosing. Upon discharge from the clinical unit participants will be monitored on an outpatient basis up to Day 50±2. Participants will receive compulsory antimalarial rescue treatment with Riamet® (artemether/lumefantrine) on Day 47±2 or earlier.
This is an open-label, adaptive study that will utilise the P. falciparum induced blood stage malaria (IBSM) model to characterise the pharmacokinetic/pharmacodynamic (PK/PD) profile of pyronaridine. Up to 18 healthy, malaria naïve adult participants are planned to be enrolled into this study, in cohorts of up to six participants each. Following a screening period of up to 28 days, cohorts of up to 6 healthy participants will be enrolled. Each participant will be inoculated intravenously on Day 0 with approximately 2,800 viable P. falciparum infected erythrocytes. Participants will be followed up daily via phone call or text message on Days 1 to 3 post-inoculation to solicit any adverse events. Participants will attend the clinical unit once on Days 4, 5, 6 and 7 for clinical evaluation and blood sampling to monitor the progression of parasitaemia, using quantitative polymerase chain reaction (qPCR) targeting the gene encoding 18S rRNA (referred to hereafter as malaria 18S qPCR). Participants will have a nasopharyngeal aspirate (NPA) for SARS-CoV-2 on Day 6 am in the event that there is community transmission in South East Queensland of SARS-CoV-2. Participants will also have blood collected on Day 7 am to monitor haematology and biochemistry. Participants will be admitted to the clinical trial unit on Day 8 for dosing with the investigational medicinal product (IMP; pyronaridine) when parasitaemia for the majority of participants is expected to be above 5,000 parasites/mL. Pyronaridine will be administered as a single oral dose. Different doses of pyronaridine will be administered across and within cohorts in order to effectively characterise the PK/PD relationship. Each cohort will comprise up to three dose groups, with participants randomised to a dose group on the day of dosing. The highest dose of pyronaridine administered will be no more than 720 mg; the lowest dose administered will be no less than 180 mg. The proposed dosing regimen for the Cohort 1, assuming six participants are enrolled, is as below. If less than six participants are enrolled the Safety Data Review Team (SDRT) will meet between Day 0 and Day 8, to decide on the dose/s to be administered. Dose group 1A (n=2) 360 mg 1B (n=2) 540 mg 1C (n=2) 720 mg Each subsequent cohort will be composed of up to 3 dose groups. If more than one dose is tested in a given cohort, subjects will be randomised after inoculation day (Day 0) but prior to Day 8. The dose/s administered to Cohort 2 and Cohort 3 will be selected based on PK/PD and safety data from the preceding cohort/s. The SDRT will review all available safety and tolerability data and PK/PD analysis outcomes from the previous cohort/s prior to inoculation of the next cohort. The study will conclude when sufficient data have been obtained to define the PK/PD parameters for pyronaridine (the primary endpoint). A maximum sample size of 18 participants administered pyronaridine is expected to be sufficient to achieve the primary endpoint. Participants will be confined in the clinical unit for at least 96 h (Days 8 - 12) to monitor the safety and tolerability of pyronaridine dosing and to ensure adequate clinical response against P. falciparum. During confinement, regular safety assessments will be performed and blood will be collected to monitor parasite clearance and pyronaridine concentration. If participants are clinically well at the end of the confinement period, they will be discharged and monitored on an outpatient basis up to Day 50±2. Participants will receive compulsory antimalarial rescue treatment with Riamet® (artemether/lumefantrine) on Day 47±2 or earlier.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
10
Single dose
Induced Blood Stage Malaria
South Bank
Brisbane, Queensland, Australia
USC Clinical Trials, Morayfield
Brisbane, Queensland, Australia
Emax
Maximum drug killing rate, calculated using the combined data from all doses/arms/groups in both period 1 and 2, as prespecified in section 10 of the Statistical Analysis Plan. The PKPD relationship was identified using SysFit as an Emax model with the parameters estimated from the parasitaemia data.
Time frame: Day 8 to Day 50+/-2
EC50
Half Maximal Effective Concentration Calculated using the combined data from all doses/arms/groups in both period 1 and 2, as prespecified in section 10 of the Statistical Analysis Plan. The PKPD relationship was identified using SysFit as an Emax model with the parameters estimated from the parasitaemia data.
Time frame: Day 8 to Day 50+/-2
Hill Coefficient
Hill coefficient is the slope of the drug concentration-response curve (i.e. response in this study is the parasite killing). Calculated using the combined data from all doses/arms/groups in both period 1 and 2, as prespecified in section 10 of the Statistical Analysis Plan. The PKPD relationship was identified using SysFit as an Emax model with the parameters estimated from the parasitaemia data. The "Emax-model" assumes a direct effect of concentrations on parasite killing/clearance, such as: Kill = Emax x (Cc\^Hill /(Cc\^Hill + EC50\^Hill)) where Cc is the concentration in the central compartment, Emax is the maximum effect of the drug, EC50 is the concentration that results in 50% of the maximum effect, and Hill is the Hill coefficient.
Time frame: Day 8 to Day 50+/-2
Minimum Inhibitory Concentration (MIC)
MIC is defined as the concentration when drug killing equals the parasite growth, i.e., the time at which the minimum parasite concentration is observed. Calculated using the combined data from all doses/arms/groups in both period 1 and 2, as prespecified in section 10 of the Statistical Analysis Plan.
Time frame: Day 8 to Day 50+/-2
Minimal Parasiticidal Concentration (MPC90)
MPC90 is defined as the concentration at which the clearance effect is at 90% of the maximum. Calculated using the combined data from all doses/arms/groups in both period 1 and 2, as prespecified in section 10 of the Statistical Analysis Plan.
Time frame: Day 8 to Day 50+/-2
Parasite Reduction Ratio in 48 h (log10PRR48)
PRR48 is defined as the parasite reduction ratio achieved within 48 hours, usually given as the reduction of values on log10 transformed scale. PRR48 provides an efficacy estimate of anti-malarial treatment and is the ratio of the parasite density over a 48 hour time-period. PRR48 is estimated using the slope of the optimal fit of the log-linear relationship of the parasitemia decay. Optimal fit is derived using the geometric mean parasitemia data (i.e. 18S qPCR measuring all blood stage malaria parasites). Optimal fit of log-linear parasitemia by time relationship is determined using left and right censoring to systematically remove potential lag phase and tail phase of parasitemia decay. The PRR48 was calculated per subject in MMV\_PYR using daily PCR data; and if the model fit was adequate for the subject (defined as overall model p-value\<0.001), the slope and corresponding standard error (SE) from the log-linear regression was used to calculate the overall dose-specific PRR48
Time frame: Day 8 to Day 50+/-2
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