Healthy ParticipantsPhase 2NAVIGATE-2NCT07225959
A Study of Annual Doses of MK-1406/CD388 in Healthy Adults (MK-1406-006/CD388.SQ.2.07)
A Phase 2 study testing MK-1406 Injection in people with Healthy Participants, run by Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA) at 6 sites in 2 countries.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 66 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Participants
- What is being tested?
- MK-1406 Injection
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 400 participants
- Where
- 6 sitesin 2 countries
- Study dates
- 29 Oct 2025to 31 Jul 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 66 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
6 sites in 2 countries.
6 sites in 2 countries
United States4 sites
Floridian Clinical Research ( Site 0102)
Miami Lakes, Florida, 33016
Floridian Clinical Research
Miami Lakes, Florida, 33016
Spartanburg Medical Research ( Site 0101)
Spartanburg, South Carolina, 29303
Spartanburg Medical Research
Spartanburg, South Carolina, 29303
United Kingdom2 sites
hVIVO Serviced Limited
London, England, E1 1EQ
hVIVO ( Site 0001)
London, London, City of, E1 1EQ
About this study
Official title: 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.
Read the 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.
- Conditions
- Healthy Participants
- Being tested
- MK-1406 Injection
- Keywords
- Influenza, Antiviral Agents
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MK-1406 InjectionCombination product
Also called CD388
MK-1406 liquid for injection administered subcutaneously
| Study group | Role | What they receive |
|---|---|---|
| MK-1406 | Experimental | 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. Receives: Combination Product: MK-1406 Injection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants with Treatment-Induced Anti-Drug Antibodies (ADAs)
Participants are evaluated for the occurrence of treatment-induced ADAs following administration of each annual dose of MK-1406.
Measured: Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
Number of Participants with Treatment-Boosted ADAs
Participants are evaluated for the occurrence of treatment-boosted ADAs following administration of each annual dose of MK-1406.
Measured: Periods 1 and 2: Day 1, Day 29, Day 85, Day 169, and Day 197
Secondary outcomes (6)
Number of participants with ≥1 Adverse Event (AE)
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.
Measured: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
Number of Participants Who Discontinued from the Study Due to an AE
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.
Measured: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
Number of Participants with a Solicited Injection-site AE
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.
Measured: Up to approximately Day 8 post dose
Number of Participants with a Serious Adverse Event (SAE)
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.
Measured: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
Plasma Concentration Following Administration of MK-1406
Blood samples will be collected at multiple time points to assess the plasma concentrations of MK-1406.
Measured: Periods 1 and 2: Pre-dose, Day 8, Day 29, Day 85, Day 169, Day 197
Plasma concentration of MK-1406 by anti-drug antibody (ADA) status.
Blood samples will be collected to assess the plasma concentration of MK-1406 where ADAs are present in participants administered MK-1406.
Measured: Periods 1 and 2: Day 197
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Nov 2025
- Study start29 Oct 2025
- Primary completion31 Jul 2027 (estimated)
- Study completion31 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy ParticipantsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 400 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07225959
- Sponsor's protocol ID
- CD388.SQ.2.07
- Other IDs
- CD388.SQ.2.07, MK-1406-006, NAVIGATE-2
- Acronym
- NAVIGATE-2
- Status last verified
- Aug 2026
- First submitted
- 6 Nov 2025
- Last updated
- 20 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Study at a glance
From the registry record, last updated by the sponsor on 20 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07225959
- Acronym / sponsor ID
- NAVIGATE-2 / CD388.SQ.2.07
- Conditions
- Healthy Participants
- Keywords
- Influenza, Antiviral Agents
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 400 participants (estimated)
- Lead sponsor
- Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)Industry (pharma, biotech, devices)
- Study start
- 29 Oct 2025 (actual)
- Primary completion
- 31 Jul 2027 (estimated)
- Study completion
- 31 Jul 2027 (estimated)
- First posted
- 10 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| MK-1406 | Experimental | Combination Product: MK-1406 InjectionParticipant 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. |
Who may qualify
- Ages
- 18 to 66 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- 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.
Key exclusion criteria (3 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MK-1406 InjectionAlso: CD388MK-1406 liquid for injection administered subcutaneously | Combination product | MK-1406 |
Primary outcome
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.
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.
6 secondary outcomes
Number of participants with ≥1 Adverse Event (AE)
Time frame: Period 1: Up to approximately Day 280. Period 2: Up to approximately Day 197.
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.
Number of Participants with a Solicited Injection-site AE
Time frame: Up to approximately Day 8 post dose
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.
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
Plasma concentration of MK-1406 by anti-drug antibody (ADA) status.
Time frame: Periods 1 and 2: Day 197
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Aug 2026.
- Merck Clinical Trials InformationLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Medical Director study director
Merck Sharp & Dohme LLC
6 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing MK-1406 Injection in people with Healthy Participants, run by Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA) at 6 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 20 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in United States, United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Aug 2026.