A Trial to Evaluate the Effect of CD388 on the Immunogenicity of Fluzone® HD Vaccine (NCT07300085) | Clinical Trial Compass
Active — Not RecruitingPhase 1
A Trial to Evaluate the Effect of CD388 on the Immunogenicity of Fluzone® HD Vaccine
United States100 participantsStarted 2025-11-08
Plain-language summary
The goal of this clinical study is to investigate how safe and effective it is to receive both the Fluzone® High-Dose (HD) influenza vaccine and CD388, a long-acting antiviral medicine, at the same time. Some participants will receive the vaccine and CD388, while others will receive the vaccine and a placebo. The study aims to determine whether taking CD388 together with the flu vaccine affects the body's ability to build protection-called an immune response-against the flu, as compared to getting the vaccine with a placebo. The hypothesis is that giving both at the same time does not weaken the immune response to the vaccine. The study will measure the amount of antibodies (proteins produced by the immune system to fight flu viruses) generated by participants in both groups to check that CD388 does not interfere with how well the vaccine works. Participants will also be closely watched for any side effects or reactions to check that CD388 is safe to take alongside the vaccine. Expanded access to the study treatments (flu vaccine and CD388) will not be provided to participants after the study ends.
Who can participate
Age range
18 Years – 49 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Be ≥ 18 to ≤ 49 years of age at the time of signing the informed consent.
. Be able to understand and comply with the trial procedures, understand the risks involved in the trial, and provide written informed consent before the first trial-specific procedure.
. Be deemed healthy by the Investigator, as determined via medical history and clinical examination before enrolling in the trial.
. Be able to complete all screening period evaluations and attend the required follow-up visits at the site.
. Have not received any seasonal influenza vaccine and have not had a diagnosed or suspected influenza infection within 12 months prior to Day 1 of the trial, based on participant self-report.
. Have a body mass index (BMI; calculated as weight in kilograms \[kg\] divided by height in meters \[m\] squared)) between 18 and 32 kg/m\^2, inclusive, and body weight not less than 50 kg at screening.
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
Immune Responses in Participants Receiving Concomitant Fluzone HD and CD388 Compared to Participants Who Receive Fluzone HD and Placebo
Timeframe: On Day 1 (pre-intervention baseline), Day 15 (±1 day), and Day 29/End of Trial (EOT) (±2 days)
Trial details
NCT IDNCT07300085
SponsorCidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)
. Have resting vital signs at screening within the following ranges:
. Systolic blood pressure ≥100 millimeters of mercury (mmHg)
Exclusion criteria
1. Be willing to abstain from alcohol, recreational drugs, and tobacco-containing and nicotine-containing products throughout their participation in the trial.
2. Have clinical chemistry, hematology, and complete urinalysis results at screening within the reference range for the testing laboratory unless the out-of-range results are deemed not clinically significant by the Investigator.
3. Be seronegative for hepatitis B surface antigen (HbsAg), hepatitis C virus antibody (HCV Ab), and human immunodeficiency virus (HIV) antibody at screening.
4. Must agree to the following contraception requirements:
5. Must agree not to donate blood from Day 1 until 40 weeks after administration of trial intervention.
6. Must be able to read, understand, and complete trial questionnaires and diary entries (paper or electronic), and, if the electronic format is used, be able to work with smartphones, tablets, or computers as applicable. Must also be willing and able to adhere to the prohibitions and restrictions specified in the protocol. If no appropriate language version of the diary or questionnaires (paper or electronic) is available, the participant should not be enrolled.
7. Must be willing to provide verifiable identification, has means to be contacted, and is able to contact the Investigator/trial site and communicate reliably during participation in this trial.
. Has a condition that the Investigator believes would interfere with the participant's ability to provide written informed consent, comply with trial instructions, or which might confound the interpretation of the trial results or put the participant at undue risk.