Inclusion Criteria:
1. Signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. For adolescents, written assent and parental/legal authorized representative (LAR) consent must be obtained, in accordance with local regulations.
2. Able to provide proof of identity to the satisfaction of the Investigator or delegate completing the enrolment process
3. Able and willing to communicate effectively and comply with all study procedures for the duration of the study (including IM injections, safety assessments, blood sampling, malaria monitoring, follow-up visits)
4. Living within local jurisdiction of trial site(s) and available for the duration of the trial Demographics and Contraception
5. Male or female participants aged 12 to 50 years inclusive at the time of signing informed consent/assent.
6. WOCBP must be non-pregnant and non-lactating, confirmed by a negative highly sensitive serum pregnancy test at screening and a negative urine pregnancy test at admission, prior to IMP administration. WOCBP must agree to use, at minimum, acceptable contraception methods, as defined by the Clinical Trials Coordination Group (CTCG) guidance, from 21 days prior to study Day 1 through the End-of Study visit (Week 24) (Clinical Trials Coordination Group (CTCG), 2024).
7. Post-menopausal participants must have menopause confirmed at screening, defined as a follicle-stimulating hormone (FSH) level ≥ 25.8 mIU/mL Baseline Characteristics
8. Healthy volunteers, as determined by:
physical examination Vital signs 12 lead ECG absence of malaria symptoms at baseline (note: a positive blood smear without malaria symptoms at baseline is not exclusionary) Hematology, biochemistry or urinalysis results at screening or at the admission visit (Day -1) that are within the standard clinically acceptable laboratory ranges defined for this study (See section 10.7 Appendix 7)
9. For adults (18-50 years): Body Weight ≥45 kg at screening
10. For adolescents (12-17 years): body weight ≥35 kg at screening Participant-reported outcomes (PROs)
11. Able to understand and complete participant-reported outcome assessments (e.g., injection-site reaction diary and injection acceptability assessments), either independently or with assistance, in a language and format approved by the Ethics Committee.
Exclusion Criteria:
* Medical Conditions
1. Positive malaria blood smear microscopy at the Admission visit (Day -1).
2. Acute febrile illness within 96 hours prior to enrolment or within 96h prior to Day 1.
3. Serious adverse reaction or clinically significant hypersensitivity to drugs or formulation excipients used in the study: artemether-lumefantrine (Coartem® or generic formulations) and atovaquone (Wellvone®/Mepron® and/or Malarone® or their generics).
4. Any history of severe allergic reaction with generalized urticaria, angioedema, or anaphylaxis prior to enrolment that, in the opinion of the Investigator, has a reasonable risk of recurrence during the trial.
5. Any current uncontrolled medical or psychiatric condition, or substance abuse problems that, in the opinion of the Investigator, would make it unlikely for the participant to comply with the protocol, may interfere with study assessments, or could jeopardize the safety of the participant.
6. Evidence of clinically significant neurologic, cardiac, gastro-intestinal, dermatologic, pulmonary, hepatic, endocrine, rheumatologic, autoimmune, haematological, oncologic, or renal disease, as determined by medical history, physical examination, and/or laboratory evaluations, including urinalysis.
7. History of a bleeding disorder diagnosed by a physician (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or a history of significant bruising with blood draws.
8. Known or documented sickle cell disease by history. Note: known sickle cell trait is not exclusionary.
9. Presence of sinus node dysfunction; clinically significant PR interval prolongation (\>220 msec); intermittent second- or third-degree atrioventricular block; complete bundle branch block; sustained cardiac arrhythmias including, but not limited to, atrial fibrillation or supraventricular tachycardia; any symptomatic arrhythmia except isolated extrasystoles; abnormal T wave morphology that may interfere with QT/QTc assessment; or QTcF \>450 msec (adults and adolescents).
Physical Examination
10. Participants who do not have adequate venous access for multiple venipunctures or cannulation, as assessed by the Investigator or delegate at screening.
11. Participants with tattoos, scars or other clinically significant dermatological lesions or conditions overlying the deltoid, gluteal, or vastus lateralis region that, in the opinion of the Investigator, may interfere with injection site assessments.
Diagnostic Assessments
12. Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab). or human immunodeficiency virus (HIV) 1 and 2 antibody results.
Prior Study Participation
13. Participants who have received any IMP in a clinical research study within the 90 days prior to Day 1, or within fewer than 5 elimination half-lives prior to Day 1 (whichever is longer). Note: Past, current, or planned participation in non-interventional (observational) studies is not exclusionary.
14. Participants who are currently enrolled in another interventional clinical trial within 90 days prior to Day 1, or who intend to participate in another interventional clinical trial during their participation in this study.
15. Donation of blood or plasma, or loss of more than 400 mL of blood, within 90 days prior to Day 1.
Prior and Concomitant Medication or Vaccine
16. Use of antimalarial chemoprevention or treatment, and/or antibiotics with known antimalarial activity (see Section 10.6 Appendix 6), within 6 weeks or fewer than 5 elimination half-lives prior to Screening (whichever is longer).
17. Current or recent (within 30 days prior to Day 1) use of rifampin/rifampicin, rifabutin, tetracycline, or indinavir due to potential drug-drug interaction risk with atovaquone.
18. Use of chronic (≥14 days) oral or IV corticosteroids (excluding topical or nasal) at immunosuppressive doses (i.e., prednisone \>10 mg/day) or other immunosuppressive drugs within 30 days prior to Day 1.
19. Receipt of a live attenuated vaccine within 4 weeks or an inactivated vaccine within 2 weeks prior to Day 1.
20. Receipt or planned receipt during the study of any doses of a malaria vaccine (investigational or registered, such as RTS, S/AS01 or R21/Matrix-M) or monoclonal antibodies (mAb) directed against Plasmodium falciparum.
21. Receipt of immunoglobulins and/or blood products within the past 6 months. Lifestyle Characteristics
22. History or medical, occupational, or family problems related to alcohol or illicit drug use within the past 12 months that, in the opinion of the Investigator, may interfere with study participation, compliance, or participant safety.
Other Exclusion Criteria
23. Participants who are, or are immediate family members of, study site staff or Sponsor employees involved in the conduct of the study.
24. Any other condition or circumstance that, in the opinion of the Investigator, would make the participant unsuitable for the study or could compromise participant safety or data integrity.
