A Study of Annual Doses of MK-1406/CD388 in Healthy Adults (MK-1406-006/CD388.SQ.2.07) (NAVIGATE-2)
August 18, 2026 updated by: Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)
A Phase 2, Open-Label, Long-Term Study to Evaluate the Safety, Pharmacokinetics, and Occurrence of Anti-Drug Antibodies in Healthy Participants Following Annual Doses of CD388, a Novel Long-Acting Antiviral Conjugate
The goal of this clinical study is to learn if giving repeated annual doses of MK-1406 (CD388) is safe and how the body reacts to it in healthy adults who have already received one dose without serious side effects.
The study aims to determine if the body makes antibodies against MK-1406 after repeated doses, which might affect how the drug works or how safe it is, and to better understand the safety and tolerability of repeated doses.
Participants will receive two doses of MK-1406 over two years and be monitored for 18 months.
Researchers will check for immune responses against the drug, watch for any side effects, and measure how the drug behaves in the body over time.
This study is based on the idea that people who tolerated MK-1406 well before will likely continue to tolerate it safely with repeated annual dosing, and that the risk of immune reactions will remain low.
Study Overview
Status
Active, not recruiting
Conditions
Intervention / Treatment
Detailed Description
This is a Phase 2, open-label, long-term study to evaluate the occurrence anti-drug antibodies (ADAs) directed to MK-1406 (CD388) following administration of 2 annual doses of MK-1406 in healthy participants during an 18-month period.
All participants previously completed study CD388.SQ.2.05/MK-1406-004, having received a dose of the active drug without experiencing any serious adverse events (SAEs) during that study.
This study will also evaluate the safety and tolerability of MK-1406 and the pharmacokinetics (PK) of MK-1406 following repeated annual dosing.
Study Type
Interventional
Enrollment (Estimated)
400
Phase
- Phase 2
Contacts and Locations
This section provides the contact details for those conducting the study, and information on where this study is being conducted.
Study Locations
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England
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London, England, United Kingdom, E1 1EQ
- hVIVO Serviced Limited
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London, City of
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London, London, City of, United Kingdom, E1 1EQ
- hVIVO ( Site 0001)
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Florida
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Miami Lakes, Florida, United States, 33016
- Floridian Clinical Research
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Miami Lakes, Florida, United States, 33016
- Floridian Clinical Research ( Site 0102)
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South Carolina
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Spartanburg, South Carolina, United States, 29303
- Spartanburg Medical Research
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Spartanburg, South Carolina, United States, 29303
- Spartanburg Medical Research ( Site 0101)
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Participation Criteria
Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
Eligibility Criteria
Ages Eligible for Study
- Adult
- Older Adult
Accepts Healthy Volunteers
Yes
Description
Inclusion Criteria:
The main inclusion criteria include but are not limited to the following:
- Be in stable health
- Has previously completed participation in study CD388.SQ.2.05/MK-1406-004, and received a subcutaneous (SC) CD388/MK-1406 dose of either 150 mg, 300 mg or 450 mg.
Exclusion Criteria:
The main exclusion criteria include but are not limited to the following:
- Have a contraindication to subcutaneous (SQ) injections and venipunctures (eg, bleeding disorders).
- Has a known or suspected allergy or history of anaphylaxis or other serious adverse events (SAEs) to zanamivir (following administration of inhaled or intravenous formulations), monoclonal antibodies, or any of the components of CD388/MK-1406.
Study Plan
This section provides details of the study plan, including how the study is designed and what the study is measuring.
How is the study designed?
Design Details
- Primary Purpose: Prevention
- Allocation: N/A
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
Experimental: MK-1406
Participant will receive 450 mg dose of MK-1406 (CD388) by subcutaneous (SC) injection followed 1 year later by a repeat single 450 mg dose of MK-1406 administered by SC injection.
|
MK-1406 liquid for injection administered subcutaneously
Other Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Number of Participants with Treatment-Induced Anti-Drug Antibodies (ADAs)
Time Frame: Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
|
Participants are evaluated for the occurrence of treatment-induced ADAs following administration of each annual dose of MK-1406.
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Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
|
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Number of Participants with Treatment-Boosted ADAs
Time Frame: Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
|
Participants are evaluated for the occurrence of treatment-boosted ADAs following administration of each annual dose of MK-1406.
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Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
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Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Number of participants with ≥1 Adverse Event (AE)
Time Frame: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
|
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 number of participants with ≥1 AE will be assessed.
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Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
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Number of Participants Who Discontinued from the Study Due to an AE
Time Frame: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
|
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 number of participants who discontinued the study because of an AE will be assessed.
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Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
|
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Number of Participants with a Solicited Injection-site AE
Time Frame: 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.
The number of participants with a solicited injection-site AE will be assessed.
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Up to approximately Day 8 post dose
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Number of Participants with a Serious Adverse Event (SAE)
Time Frame: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
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An SAE is an AE that results in death, is life threatening, results in a persistent or significant disability or incapacity, results in or prolongs an existing hospitalization, is a congenital anomaly or birth defect, is a cancer, is an overdose, or is another important medical event.
The number of participants with an SAE will be assessed.
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Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
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Plasma Concentration Following Administration of MK-1406
Time Frame: Periods 1 and 2: Pre-dose, Day 8, Day 29, Day 85, Day 169, Day 197
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Blood samples will be collected at multiple time points to assess the plasma concentrations of MK-1406.
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Periods 1 and 2: Pre-dose, Day 8, Day 29, Day 85, Day 169, Day 197
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Plasma concentration of MK-1406 by anti-drug antibody (ADA) status.
Time Frame: Periods 1 and 2: Day 197
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Blood samples will be collected to assess the plasma concentration of MK-1406 where ADAs are present in participants administered MK-1406.
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Periods 1 and 2: Day 197
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Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Investigators
- Study Director: Medical Director, Merck Sharp & Dohme LLC
Publications and helpful links
The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.
Helpful Links
Study record dates
These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.
Study Major Dates
Study Start (Actual)
October 29, 2025
Primary Completion (Estimated)
July 31, 2027
Study Completion (Estimated)
July 31, 2027
Study Registration Dates
First Submitted
November 6, 2025
First Submitted That Met QC Criteria
November 6, 2025
First Posted (Actual)
November 10, 2025
Study Record Updates
Last Update Posted (Actual)
August 20, 2026
Last Update Submitted That Met QC Criteria
August 18, 2026
Last Verified
August 1, 2026
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- CD388.SQ.2.07 (Other Identifier: Cidara)
- MK-1406-006 (Other Identifier: MSD)
- NAVIGATE-2 (Other Identifier: Cidara)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
YES
IPD Plan Description
https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Yes
Studies a U.S. FDA-regulated device product
No
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