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A Trial to Evaluate the Effect of CD388/MK1406 on the Immunogenicity of Fluzone® HD Vaccine (CD388.SQ.1.08/MK-1406-007)

NCT07300085 · Status: ACTIVE_NOT_RECRUITING · Phase: PHASE1 · Type: INTERVENTIONAL · Enrollment: 710

Last updated 2026-08-19

No results posted yet for this study

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®

Conditions

  • Healthy Participants

Interventions

BIOLOGICAL

Fluzone® High-Dose (HD) influenza vaccine

Fluzone® HD injectable suspension administered by intramuscular (IM) injection

COMBINATION_PRODUCT

MK-1406 Injection

MK-1406 liquid for injection administered subcutaneously

COMBINATION_PRODUCT

Placebo

MK-1406 matched liquid for SC injection

Sponsors & Collaborators

  • Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)

    lead INDUSTRY

Principal Investigators

  • Medical Director · Merck Sharp & Dohme LLC

Study Design

Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
49 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2025-11-08
Primary Completion
2026-12-31
Completion
2026-12-31
FDA Drug
Yes

Countries

  • United States

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07300085 on ClinicalTrials.gov