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Phase 2 N=620 Randomized Other

Study of Malaria Vaccine RTS,S/AS01E in Plasmodium Falciparum-infected and Uninfected Adults Pre-treated With Anti-malarial Therapy

Plasmodium Falciparum

Enrolled (actual)
620
Serious AEs
1.7%
Results posted
Jul 2024
Primary outcome: Primary: Time to First PCR-detectable Malaria Infection During the Active Detection of Infection (ADI) Phase in Groups 1 and 4 — 1.01; 1.49 Events per person year at risk — p=0.009

Study Design & Population

Study type
Interventional
Phase
Phase 2
Interventions
Malaria Vaccine RTS,S/AS01E (Biological); Abhayrab rabies vaccine (Biological); Dihydroartemisinin-piperaquine (DHA/Pip) (Drug); Artemether / Lumefantrine (Drug); Primaquine (Drug)
Age
Adult · 18+ yrs
Sex
All
Sponsor
PATH
Primary completion
Jun 2022

Outcome Measures

OutcomeResultp-value
PRIMARY
Time to First PCR-detectable Malaria Infection During the Active Detection of Infection (ADI) Phase in Groups 1 and 4
1.01; 1.49 0.009 sig
SECONDARY
Time to First PCR-detectable Malaria Infection During the Active Detection of Infection Phase in Groups 2 and 5
0.77; 0.62 0.369
SECONDARY
Number of Participants With Serious Adverse Events (SAEs)
3; 2; 1; 1; 3
SECONDARY
Number of Participants With Solicited Local and Systemic Adverse Events (AEs)
24; 26; 14; 20; 16; 14
SECONDARY
Number of Participants With Unsolicited Adverse Events
103; 87; 20; 110; 92
SECONDARY
Geometric Mean Titer of Anti-Plasmodium Falciparum Circumsporozoite (CS) Antibodies in Groups 1, 2, and 3
171.89; 139.80; 231.64; 2328.78; 2538.76; 2744.34
SECONDARY
Anti-Plasmodium Falciparum Circumsporozoite (CS) Antibody Avidity Index in Groups 1, 2, and 3
0.62; 0.64; 0.65; 0.64; 0.67; 0.69
SECONDARY
Geometric Mean Titer (GMT) of Anti-Hepatitis B Surface Antigen (HBsAg) Antibodies in Groups 1, 2, and 3
16.88; 14.32; 15.57; 61.27; 60.16; 87.89

Summary

The main goal of this study is to assess the efficacy of RTS,S/AS01E, a candidate vaccine against malaria caused by Plasmodium falciparum (P. falciparum), in adults positive for P. falciparum at the start of the study, but treated with anti-malarial medications to clear the parasite before receiving multiple doses of the vaccine. The goal is to overcome the reduced vaccine efficacy (hypo-responsiveness to the vaccine) reported in actively or chronically infected adults.

Eligibility Criteria

Inclusion Criteria

  • Provision of signed or thumb printed and dated informed consent form
  • Stated willingness to comply with all study procedures and availability for the duration of the study
  • Male or female between 18 and 55 years of age, inclusive
  • In good general health as evidenced by medical history and clinical examination before entering the study
  • Ability to take oral medication and be willing to adhere to the medication regimen
  • For females, she must be of non-childbearing potential or use appropriate measures to prevent pregnancy for 30 days prior to vaccination through 2 months after completion of the vaccine series. Non-childbearing potential means she is surgically sterilized or at least one year post-menopausal. Appropriate measures to prevent pregnancy include abstinence or adequate contraceptive precautions (i.e. intrauterine contraceptive device; oral contraceptives; diaphragm or condom in combination with contraceptive jelly, cream or foam; Norplant or Depo-Provera). Clinical trial site staff will assist with provision of acceptable birth control for study entry and will discuss with volunteer at screening visit.

Exclusion Criteria

  • Planned administration/administration of a vaccine not foreseen by the study protocol from within 30 days before the first dose of study vaccine until 30 days after the last dose of study vaccine.†

† In the context of the COVID-19 pandemic, the administration of the COVID-19 vaccine will be allowed as an exception to this exclusion criteria as follows. The study team will work with the participant to attempt to have any COVID-19 vaccine administration occur 30 days or more before or after study vaccinations. When this is not possible, COVID-19 vaccination will be allowed 10 days or more before or after study vaccination. Intervals shorter than 10 days can be allowed on a case-by-case basis in discussion with the sponsor.

  • Any prior receipt of any rabies vaccine or experimental malaria vaccine.
  • Confirmed or suspected significant immunosuppressive or immunodeficient condition as determined by the investigator, including clinical stage 3 or 4 human immunodeficiency virus (HIV) infection.
  • A family history of congenital or hereditary immunodeficiency.
  • History of allergic reactions, significant immunoglobulin E (IgE)-mediated events or anaphylaxis to previous immunizations.
  • History of any neurologic disorders.
  • Acute disease (defined as the presence of a moderate or severe illness with or without fever), including acute malaria, at the time of enrolment. All vaccines can be administered to persons with a minor illness, such as diarrhea or mild upper respiratory infection without fever, i.e. Oral temperature < 37.5°C*. Individuals excluded with acute disease, including acute malaria, can become eligible again after complete recovery of the illness, including appropriate treatment as applicable, and can be rescreened at a later date. *Temperature readings may be taken by site staff either using either oral, axillary, or infrared thermal thermometers during clinic or field visits, while subjects enrolled in the reactogenicity cohort will be supplied with oral thermometers for the purposes of recording their own temperature measurements in the memory aid over 7 days after each vaccination.
  • Acute or chronic, clinically significant pulmonary, cardiovascular (including cardiac arrythmias) , hepatic or renal functional abnormality, as determined by medical history, physical examination or laboratory screening tests.
  • History of homozygous sickle cell disease (Hgb SS).
  • Any clinically significant laboratory abnormalities as determined by the investigator on screening labs.
  • History of splenectomy.
  • Administration of immunoglobulins, blood transfusions or other blood products within the three months preceding the first dose of study vaccine or planned administration during the study period.
  • Pregnant (i.e. a positive pregnancy test) or lactating female during immuniz
View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT04661579). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.

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