Phase II Dose-ranging Study of Pyronaridine/Artesunate in Adults Patients With Plasmodium Falciparum Malaria

The primary trial objective is to determine the clinically effective dose of orally administered pyronaridine/artesunate (Pyramax®, PA) with a 3:1 ratio to treat adults with acute, symptomatic, uncomplicated P. falciparum malaria in South East Asia and Africa. Secondary trial objectives are to determine the safety of once-daily dosing for 3 days of PA and to explore possible ethnic differences in safety or efficacy.

This is a double-blind, multicentre, randomized, parallel group, dose-finding study of the efficacy, safety and tolerability of a once-daily 3-day regimen of PA with a 3:1 weight/weight ratio for patients with acute, symptomatic, uncomplicated P. falciparum malaria. Patients will be recruited from 5 to 7 study sites in endemic regions of South East Asia and Africa and will be randomized to 1 of 3 treatment groups differing in dosage, with 160 patients per group (n-480). Randomization will be balanced within each study site across all 3 study groups in pre-assigned treatment blocks.

The first dose will be administered on Day 0 and patients will remain hospitalized for at least 4 days whilst undertaking the 3-day regimen. Patients will remain near the study site for a minimum of 7 days or once fever and parasite clearance is confirmed (assessed by 3 negative readings of fever and/or slide).

The primary efficacy end point is the cure rate on Day 28 - the proportion of patients with PCR-corrected adequate clinical and parasitological response (ACPR). Despite this Day 28 end point, the relatively long half-life of pyronaridine necessitates follow-up until Day 42. In the case of adverse events reported and unresolved at Day 42, patients will be followed up for a further 30 days, or until resolution of the event.

Eligibility Criteria:
Inclusion Criteria:

1. Male or female patients between the age of 15 and 60 years of age inclusive
2. Written informed consent, in accordance with local practice, provided by patient and/or parent/guardian/spouse. If the patient is unable to write, witnessed consent is permitted according to local ethical considerations
3. Absence of severe malnutrition (defined as the weight-for-height being below -3 standard deviations or \<70% of the median of the NCHS/WHO normalized reference values)
4. Weight of between 35 kg and 75 kg inclusive
5. Presence of acute symptomatic uncomplicated P. falciparum malaria with a diagnosis confirmed by a positive blood smear with asexual forms of P. falciparum only (i.e. no mixed infection) plus history of fever within the previous 24 hours or a measured temperature of ≥37.5°C (depending on method of measurement):

   * the acceptable range is between 1,000 and 100,000 asexual parasite count/μl of blood and
   * axillary/tympanic temperature of ≥ 37.5°C or oral/rectal temperature of ≥ 38.0°C
6. Ability to swallow oral medication
7. Ability to comply with study visit schedule: patients will be hospitalised for at least 4 days and will be required to remain in the vicinity of the trial site for a minimum of 7 days or until clearance of fever and parasite for at least 24 hours, whichever is the later. The patient is to return to the study site or to make themselves available for all scheduled follow up visits, until discharge at Day 42.
8. Females must not be pregnant or lactating and be willing to take measures to not become pregnant during the study period
9. Willingness and ability to comply with the study protocol for the duration of the study

Exclusion Criteria:

1. Patients with signs and symptoms of severe/complicated malaria requiring parenteral treatment according to the World Health Organization Criteria 2000
2. Mixed Plasmodium infection
3. Severe vomiting, defined as \>3 times in the 24 hours prior to inclusion in the trial or inability to tolerate oral treatment
4. Known history or evidence of clinically significant disorders such as cardiovascular (including arrhythmia), respiratory (including active tuberculosis), hepatic, renal, gastrointestinal, immunological (including active HIV-AIDS), neurological (including auditory), endocrine, infectious, malignancy, psychiatric or other clinically important abnormality (including head trauma).
5. Presence of febrile conditions caused by diseases other than malaria
6. Known history of hypersensitivity, allergic or adverse reactions to pyronaridine or artesunate or other artemisinins
7. Evidence of use of any other antimalarial agent within 2 weeks prior to the start of the study confirmed by a negative urine test or using Eggelte dipsticks
8. Positive urine pregnancy test or lactating
9. Received an investigational drug within the past 4 weeks
10. Known active Hepatitis A IgM (HAV-IgM), Hepatitis B surface antigen (HBsAg) or Hepatitis C antibody (HCV Ab)
11. Known seropositive HIV antibody
12. Liver function tests \[ASAT/ALAT levels\] \>2.5 times upper limit of normal values
13. Known significant renal impairment as indicated by a serum creatinine of ≥ 1.4 mg/dl
14. Previous participation in this clinical trial