A Strep Throat Controlled Human Infection Trial in Healthy Adults (NCT06992141) | Clinical Trial Compass
CompletedEarly Phase 1
A Strep Throat Controlled Human Infection Trial in Healthy Adults
Australia40 participantsStarted 2025-07-24
Plain-language summary
This aim of this study is to further develop a new way to study the bacteria that causes pharyngitis (strep throat). The scientific name for this bacterium is Streptococcus pyogenes and it is commonly known as Strep A. Strep A is a common type of bacteria that can cause various infections. These range from skin infections and strep throat to more serious conditions like rheumatic heart disease. In recent years there has been an increase in severe Strep A infections in most countries. Many of these cases have been reported in the news.
Human challenge models are studies which allow researchers to study organisms that cause infections in humans. In this human challenge model study, healthy participants will be carefully exposed to a specific type of Strep A under controlled conditions to cause sore throat and learn more about how Strep A causes infection. The study team has already developed a safe human challenge model using a strain of Strep A called M75. This study will use a different strain of Strep A, called M1.
The main goal of this study is to check if the procedure is safe for participants and to understand how the participant's body responds to M1 Strep A. The study will explore:
1. How much M1 Strep A is required to cause an infection.
2. How M1 Strep A grows in the body.
3. How the body reacts to M1 Strep A.
The information the investigators will get about M1 Strep A from this study will help plan future research. It may also help in designing better studies to test vaccines against Strep A.
Who can participate
Age range
18 Years – 40 Years
Sex
ALL
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Males or females, aged 18 - 40 years (inclusive) on the day of informed consent.
. Medically healthy, which can be determined by medical history, physical examination, BMI, transthoracic echocardiogram, non-clinically significant laboratory profiles, vital signs, and 12-lead ECG at screening, as deemed necessary by the research physician or investigator.
. Systolic blood pressure (SBP) of 90 mmHg - 140 mmHg and diastolic blood pressure (DBP) of 60 mmHg - 90 mmHg. Vital signs can be repeated up to two times.
. Resting heart rate (HR) of 55-100 bpm (confirmed by one repeat at screening).
. Females must be non-pregnant, non-lactating, or postmenopausal for at least 1 year (as confirmed by follicle-stimulating hormone \[FSH\]), or surgically sterile for at least 6 months prior to dosing.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
The proportion of participants at each dose level of M1 S. pyogenes who reach the study pharyngitis endpoint
Timeframe: Up to 5 days after the challenge dose of M1 S. pyogenes is administered
. Males must not have a pregnant partner and must agree to use condoms as a method of contraception from the time of signing informed consent until the second planned outpatient visit approximately 1 month following the inpatient challenge admission.
. Must be willing and able to read, understand, and sign the participant information and consent form. Willing to comply with all study requirements, including the inpatient period and outpatient visits for the duration of the study (approx. 3 months).
. Willing to abstain from the use of mouthwash from the day of screening until the first outpatient visit at one week post discharge.
Exclusion criteria
. History of any clinically important cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, and renal, or other major disease, as determined by the Investigator.
. Significant history of hospitalisation for illness within the six months prior to enrolment into study, or major surgery within the 12 months prior to enrolment into study, as assessed by research physician or investigator.
. History of tonsillectomy, adenoidectomy or splenectomy.
. Known or suspected autoimmune disease or impairment/alteration of immune function resulting from:
. Congenital or acquired immunodeficiency (including immunoglobulin A \[IgA\] deficiency)
. Receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months.
. History of a severe drug reaction or severe allergic reaction (eg. anaphylaxis, convulsions) or clinically significant allergic disease diagnosed by a physician.
. Personal or family history of severe S. pyogenes infection (toxic shock syndrome, necrotizing fasciitis, bloodstream infection, pleural empyema, meningitis) or post-infectious sequelae (such as acute rheumatic fever, rheumatic heart disease, post-streptococcal glomerulonephritis).