Healthy Participants
Conditions
Keywords
Influenza, Antiviral Agents
Brief summary
Approximately one billion cases of seasonal influenza occur annually. Of these, 3 to 5 million illnesses are severe and responsible for up to 650,000 deaths per year (WHO 2025). Yearly administration of an influenza vaccine for the prevention of influenza is currently recommended. However, the real-world vaccine effectiveness varied from 10% to 60% in the general population across the years of 2004 to 2024, with effectiveness in most years below 50% (CDC 2025) and decreasing to as low as 5% in immunocompromised individuals (Hughes 2021). Researchers are looking for other ways to prevent severe illness from the influenza virus. The goals of this study are to learn if: * MK-1406 (formerly CD388) is safe to take with Fluzone® * MK-1406 affects the immune response to Fluzone®
Detailed description
This is a Phase 1, double-blind, randomized trial to evaluate the immunogenicity of Fluzone® HD influenza vaccine when concomitantly administered with either MK-1406 or placebo, in healthy participants. This study will also evaluate the safety and tolerability of MK-1406 when administered with Fluzone® High-Dose (HD) compared to Fluzone® HD with placebo.
Interventions
BIOLOGICALFluzone® High-Dose (HD) influenza vaccine
Fluzone® HD injectable suspension administered by intramuscular (IM) injection
COMBINATION_PRODUCTMK-1406 Injection
MK-1406 liquid for injection administered subcutaneously
COMBINATION_PRODUCTPlacebo
MK-1406 matched liquid for SC injection
Sponsors
Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 49 Years
Healthy volunteers
Yes
Inclusion criteria
The main inclusion criteria include but are not limited to the following: * Be ≥18 to ≤49 years of age * Be deemed healthy by the Investigator * 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
Exclusion criteria
The main
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Geometric Mean of Hemagglutinin Inhibition (HAI) Titers Against the Influenza Strains Contained in the Vaccine Among Participants Receiving Concomitant Fluzone® High-Dose (HD) and MK-1406 Compared to Participants Who Receive Fluzone® HD and Placebo | Predose (Day 1), Day 15 and Day 29 | Geometric mean of HAI titers at 2-weeks and 4-weeks post-trial intervention against the influenza virus strains contained in the vaccine among participants receiving concomitant Fluzone® HD influenza vaccine and MK-1406 compared to participants who receive Fluzone® HD and placebo will be determined. HAI testing will be performed using validated methods in accordance with applicable Good Clinical Laboratory Practice (GCLP) and laboratory Standard Operating Procedures (SOPs). Geometric Mean Titers (GMTs) will be summarized by treatment group and influenza strain. |
| Percentage of Participants with Seroconversion Rates against the Influenza Strains Contained in the Vaccine Among Participants Receiving Concomitant Fluzone® HD and MK-1406 Compared to Participants Who Receive Fluzone® HD and Placebo | Predose (Day 1), Day 15 and Day 29 | Seroconversion is defined as a 4-fold increase in influenza titer as measured by HAI assay at each visit compared to baseline. Seroconversion rates at 2-weeks and 4-weeks post-trial intervention against the influenza virus strains contained in the vaccine among participants receiving concomitant Fluzone® HD influenza vaccine and MK-1406 compared to participants who receive Fluzone® HD and placebo will be determined. Seroconversion rates will be summarized by treatment group and influenza strain. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Participants with a Solicited Systemic Adverse Event | Up to approximately Day 29 | An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The solicited systemic AEs assessed are muscle pain/myalgia, joint pain/arthralgia, headache, and tiredness/fatigue. |
| Percentage of participants with ≥1 Adverse Event (AE) | Up to approximately Day 29 | An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product temporally associated with the use of study treatment, whether or not considered related to the study treatment. |
| Percentage of Participants Who Discontinued from the Study Due to an Adverse Event | Up to approximately Day 29 | An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product temporally associated with the use of study treatment, whether or not considered related to the study treatment. The percentage of participants who discontinued the study because of an AE (as defined above) will be assessed. |
| Percentage of Participants with a Solicited Injection-site Adverse Event | Up to approximately Day 8 post-dose | An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The solicited injection-site AEs assessed are redness/erythema, swelling, and tenderness/pain. |
Countries
United States
Contacts
STUDY_DIRECTORMedical Director
Merck Sharp & Dohme LLC
Outcome results
None listed