COVID-19Phase 2NCT07215520
Safety and Tolerability of a Newcastle Disease Virus-Based Mucosal COVID-19 Vaccine in Previously Vaccinated Adults
A Phase 2 study testing NDV-HXP-S-KP.2 and COVID-19 mRNA Vaccine in people with COVID-19, run by CastleVax Inc. at 2 sites in United States.
Trial summary
A Double-blind, Randomized, Controlled, Phase 2a Study to Evaluate the Safety and Tolerability of a Newcastle Disease Virus-based Mucosal Vaccine (NDV-HXP-S-KP.2) Relative to an Approved Systemic mRNA Vaccine in Previously Vaccinated Adults Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- COVID-19
- What is being tested?
- NDV-HXP-S-KP.2 and COVID-19 mRNA Vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 2 sitesUnited States
- Study dates
- 3 Nov 2025to 6 Sep 2026
- 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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Is an adult 18 through 64 years of age at time of screening with at least 1 underlying condition that puts the participant at high risk for severe outcomes of COVID-19 per self-report OR is an adult ≥65 years of age at time of screening (with or without at least 1 underlying condition).
- Has completed any WHO/FDA-authorized or approved primary COVID-19 vaccination series per self-report.
- Has received last COVID-19 vaccine ≥6 months prior to study vaccination.
- If a female of childbearing potential who is sexually active, agrees to use an adequate method of birth control from Screening through 90 days after study vaccination, and has used an adequate birth control method for at least 30 days prior to Screening. Sexually active male participants, unless the participant is sterile or otherwise unable to produce sperm, or has exclusively male sexual partners, must agree to abstinence or to use a barrier method (e.g., male condom) from vaccination through 90 days after study vaccination. Male participants must also agree to not donate sperm from vaccination through 90 days after study vaccination.
- Is medically stable, as determined by the site investigator (based on review of health status, vital signs, medical history, and physical examination).
- Agrees to not participate in any other SARS-CoV-2 infection prevention trial (vaccine, drug, biologic, pre-exposure prophylaxis [PrEP]) during participation in the study.
- Willing and able to provide informed consent prior to initiation of study procedures.
- Is available for all study visits, willing to participate in all study procedures, and not planning to relocate from the area for the duration of the study.
Who cannot join
- Has an acute illness, as determined by the site investigator, within 72 hours prior to Screening or study vaccination.
- Has had a positive COVID-19 test within the 90 days prior to Screening or study vaccination.
- Current or planned participation in any other interventional clinical trial.
- Participation in research involving any investigational product within 45 days prior to Screening or study vaccination.
- Receipt of any approved or authorized products intended to prevent SARS-CoV-2 infection within 6 months prior to Screening or study vaccination.
- Receipt of blood products or immunoglobulins within 60 days prior to Screening or study vaccination.
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- Received influenza vaccination within 14 days prior to Screening or study vaccination, or any other vaccine within 30 days prior to Screening or study vaccination.
- Any significant autoimmune, immunodeficiency disease/condition, or auto inflammatory disorder (e.g., any known immunoglobulin A [IgA] deficiency, human immunodeficiency virus [HIV] infection, acquired immunodeficiency syndrome [AIDS])
- Has current active hepatitis B or hepatitis C infection (based on self-reported medical history).
- Has a peripheral arterial oxygen saturation (SpO2) level <92% at Screening, uncontrolled or severe asthma (e.g., more than 1 hospitalization for asthma exacerbation within the 12 months prior to Screening), or other uncontrolled or severe chronic lung disease or known bronchial hyper-reactivity to viruses that, in the opinion of the site investigator, would pose a health risk to the individual if enrolled.
- Has known active tuberculosis.
- Unstable non-cardiac illness (acute or chronic illness) requiring hospitalization or medical procedure during the 90 days prior to Screening or study vaccination, or cardiac condition (acute or chronic) requiring hospitalization or medical procedure (e.g., stenting, cardiac surgery, etc.) during the 1 year prior to Screening or study vaccination.
- History of myocarditis, pericarditis, myopericarditis, or idiopathic cardiomyopathy, or presence of any medical condition (e.g., viral illness within 30 days of Screening or study vaccination) that, in the opinion of the investigator, increases risk of myocarditis, pericarditis, or myopericarditis.
- Chronic kidney disease requiring dialysis or any type of ultrafiltration. Individuals with chronic kidney disease that does not require dialysis or ultrafiltration may be included.
- Individuals with advanced or decompensated chronic liver disease as determined by the site investigator.
- Presence of any transplanted solid organs (heart, kidney, lung, liver, pancreas, and/or intestine) or prior receipt of a blood stem cell transplant.
- Administration of immunosuppressants, systemic glucocorticoids, or other immune-modifying drugs within the following timeframes:
- B-cell therapies within the 6 months prior to Screening or study vaccination.
- Prednisone, ≥20 mg or equivalent for more than 2 weeks, within the 30 days prior to Screening or study vaccination.
- Monoclonal antibodies that may suppress aspects of immune response (e.g., Dupixent) within the 6 months prior to Screening or study vaccination.
- Other medications in this category, including but not limited to high-dose inhaled corticosteroids (>800 mcg/day of beclomethasone dipropionate or equivalent); antimetabolites; transplant immunosuppressive agents; alkylating agents; cell-depleting agents; or cancer chemotherapeutics, within the 90 days prior to Screening or study vaccination.
- Any medication for any period of time that, in the opinion of the site investigator, could impede immune response to vaccination.
- Known contraindication to IM injection (e.g., bleeding diathesis, acquired coagulopathy) or to IN administration (e.g., significant nasal abnormality or severe nasal obstruction, significant chronic rhinitis or history of chronic rhinitis, nasal septal defect causing significant breathing problems, unrepaired cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration).
- Receipt or anticipated receipt, within 7 days prior through 7 days after study vaccination, of any Intranasal medication, including FDA-approved prescription or over-the-counter products or non-FDA-approved alternative medicine products (e.g., Ayurvedic oil or other naturopathic substances).
- Anticipated use of nasal irrigation (e.g., Neti PotTM) from Screening through 30 days after study vaccination.
- Any known allergies to components contained in NDV-HXP-S (including egg products) or the comparator vaccine (including polyethylene glycol [PEG] allergies).
- Women who are pregnant, breastfeeding, or who plan to become pregnant during the study.
- Current or prior potential for NDV exposure (e.g., prior NDV-based vaccination, NDV-based oncologic immunotherapy, prior or current experience as a bird-handler, poultry farmer, or scientist conducting research with NDV).
- Individuals who will have close or household high-risk contacts, within 14 days following study vaccination, including but not limited to:
- Any other condition that, in the opinion of the site investigator, would pose a health risk to the participant if enrolled or could interfere with evaluation of the investigational product or interpretation of study results.
- Study team member or first-degree relative of any study team member (inclusive of CastleVax and site personnel involved in the study).
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Skylight Health Research
Burlington, Massachusetts, 01803
Skylight Health Research
Colorado Springs, Colorado, 80917
About this study
Official title: A Double-blind, Randomized, Controlled, Phase 2a Study to Evaluate the Safety and Tolerability of a Newcastle Disease Virus-based Mucosal Vaccine (NDV-HXP-S-KP.2) Relative to an Approved Systemic mRNA Vaccine in Previously Vaccinated Adults
A Double-blind, Randomized, Controlled, Phase 2a Study to Evaluate the Safety and Tolerability of a Newcastle Disease Virus-based Mucosal Vaccine (NDV-HXP-S-KP.2) Relative to an Approved Systemic mRNA Vaccine in Previously Vaccinated Adults
Read the detailed description
This is a double-blind (supported by a double-dummy design), randomized, active comparator-controlled Phase 2a safety and tolerability study. The study will enroll approximately 200 previously COVID-19-vaccinated, male and nonpregnant female adult participants aged ≥18 years. Participants 18 through 64 years of age must have at least 1 underlying condition that puts them at high risk for severe outcomes from COVID-19
- Conditions
- COVID-19
- Being tested
- NDV-HXP-S-KP.2, COVID-19 mRNA Vaccine
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
NDV-HXP-S-KP.2Biological
Nasal Administration of a COVID-19 vaccine to compare against a commercially available mRNA vaccine
COVID-19 mRNA VaccineBiological
Used as a comparator to study vaccine
| Study group | Role | What they receive |
|---|---|---|
| IN administration of study drug plus placebo via IM | Experimental | Nasal Administration of NDV-HXP-S-KP.2 and administration of placebo via Intramuscular Injection Receives: Biological: NDV-HXP-S-KP.2 |
| IN administration of placebo plus COVID-19 vaccine via IM | Active comparator | Nasal Administration of Placebo plus administration of COVID-19 mRNA vaccine via Intramuscular Injection Receives: Biological: COVID-19 mRNA Vaccine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Safety and Tolerability of the NDV-HXP-S-KP.2 Vaccine Compared With an Approved mRNA COVID-19 Vaccine
Safety and tolerability of the NDV-HXP-S-KP.2 vaccine given intranasally and an approved mRNA COVID-19 vaccine given intramuscularly will be assessed in previously immunized adults. Outcomes include the percentage of participants with solicited local and systemic reactogenicity symptoms through 7 days, unsolicited adverse events through 30 days, and serious, medically attended, or special interest adverse events through 180 days. Clinically significant abnormal lab results (chemistry and hematology) will also be assessed through 7 days post-vaccination.
Measured: Up to 180 days after vaccination
Secondary outcomes (3)
Percentage of Participants With Viral Vector-Related Illness or Shedding After Vaccination
The percentage of participants who experience symptoms suggestive of viral vector-related illness at Days 2, 8, 14, and 31 after vaccination will be assessed. The percentage of participants who test positive for viral vector shedding on Day 1 and at Days 2, 8, 14, and 31 post-vaccination will also be evaluated. In addition, the study will monitor whether any household contacts of participants develop symptoms of potential viral vector-related illness at Days 2 and 8 after vaccination.
Measured: Through Day 31 post-vaccination
Humoral Immune Response to the NDV-HXP-S-KP.2 Vaccine Compared With the Comparator Vaccine
The humoral immune response to the NDV-HXP-S-KP.2 vaccine administered intranasally and the comparator vaccine administered intramuscularly in previously immunized adults will be assessed through Day 181 after vaccination. Measurements will include serum geometric mean titers (GMTs) of SARS-CoV-2-specific neutralizing antibodies at Day 1 and at Days 31, 91, and 181 post-vaccination; serum geometric mean fold rise (GMFR) of SARS-CoV-2-specific neutralizing antibodies relative to Day 1 at Days 31, 91, and 181; serum GMTs of spike (S) protein-specific immunoglobulin G (IgG) binding antibodies at Day 1 and at Days 31, 91, and 181; and serum GMFR of S protein-specific IgG binding antibodies relative to Day 1 at Days 31, 91, and 181 post-vaccination.
Measured: From Day 1 through Day 181 post-vaccination
Mucosal Immune Response to the NDV-HXP-S-KP.2 Vaccine Compared With the Comparator Vaccine
The mucosal immune response to the NDV-HXP-S-KP.2 vaccine administered intranasally and the comparator vaccine administered intramuscularly in previously immunized adults will be assessed through Day 181 after vaccination. Measurements will include the nasal lining fluid (NLF) geometric mean titers (GMTs) of spike (S) protein-specific secretory immunoglobulin A (sIgA) binding antibodies and total sIgA at Day 1 and at Days 31, 91, and 181 post-vaccination, as well as the geometric mean fold rise (GMFR) of S protein-specific sIgA binding antibodies and total sIgA relative to Day 1 at Days 31, 91, and 181 post-vaccination.
Measured: From Day 1 through Day 181 post-vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Oct 2025
- Study start3 Nov 2025
- Primary completion6 Sep 2026 (estimated)
- Study completion6 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies 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
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- CastleVax Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Michael Egan, PhD, Study chair, CastleVax Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07215520
- Sponsor's protocol ID
- CVX NDV-HXP-S-KP.2-2a
- Status last verified
- Jul 2026
- First submitted
- 1 Oct 2025
- Last updated
- 22 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: IPD will only be used internally at CastleVax for evaluation of the study outcomes.
Study at a glance
From the registry record, last updated by the sponsor on 22 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Double-blind, Randomized, Controlled, Phase 2a Study to Evaluate the Safety and Tolerability of a Newcastle Disease Virus-based Mucosal Vaccine (NDV-HXP-S-KP.2) Relative to an Approved Systemic mRNA Vaccine in Previously Vaccinated Adults
- ClinicalTrials.gov ID
- NCT07215520
- Acronym / sponsor ID
- CVX NDV-HXP-S-KP.2-2a
- Conditions
- COVID-19
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- CastleVax Inc.Industry (pharma, biotech, devices)
- Study start
- 3 Nov 2025 (actual)
- Primary completion
- 6 Sep 2026 (estimated)
- Study completion
- 6 Sep 2026 (estimated)
- First posted
- 10 Oct 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.
A Double-blind, Randomized, Controlled, Phase 2a Study to Evaluate the Safety and Tolerability of a Newcastle Disease Virus-based Mucosal Vaccine (NDV-HXP-S-KP.2) Relative to an Approved Systemic mRNA Vaccine in Previously Vaccinated Adults
Detailed description
This is a double-blind (supported by a double-dummy design), randomized, active comparator-controlled Phase 2a safety and tolerability study. The study will enroll approximately 200 previously COVID-19-vaccinated, male and nonpregnant female adult participants aged ≥18 years. Participants 18 through 64 years of age must have at least 1 underlying condition that puts them at high risk for severe outcomes from COVID-19
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| IN administration of study drug plus placebo via IM | Experimental | Biological: NDV-HXP-S-KP.2Nasal Administration of NDV-HXP-S-KP.2 and administration of placebo via Intramuscular Injection |
| IN administration of placebo plus COVID-19 vaccine via IM | Active comparator | Biological: COVID-19 mRNA VaccineNasal Administration of Placebo plus administration of COVID-19 mRNA vaccine via Intramuscular Injection |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Is an adult 18 through 64 years of age at time of screening with at least 1 underlying condition that puts the participant at high risk for severe outcomes of COVID-19 per self-report OR is an adult ≥65 years of age at time of screening (with or without at least 1 underlying condition).
- Has completed any WHO/FDA-authorized or approved primary COVID-19 vaccination series per self-report.
- Has received last COVID-19 vaccine ≥6 months prior to study vaccination.
- If a female of childbearing potential who is sexually active, agrees to use an adequate method of birth control from Screening through 90 days after study vaccination, and has used an adequate birth control method for at least 30 days prior to Screening. Sexually active male participants, unless the participant is sterile or otherwise unable to produce sperm, or has exclusively male sexual partners, must agree to abstinence or to use a barrier method (e.g., male condom) from vaccination through 90 days after study vaccination. Male participants must also agree to not donate sperm from vaccination through 90 days after study vaccination.
- Is medically stable, as determined by the site investigator (based on review of health status, vital signs, medical history, and physical examination).
Key exclusion criteria (31 listed)
- Has an acute illness, as determined by the site investigator, within 72 hours prior to Screening or study vaccination.
- Has had a positive COVID-19 test within the 90 days prior to Screening or study vaccination.
- Current or planned participation in any other interventional clinical trial.
- Participation in research involving any investigational product within 45 days prior to Screening or study vaccination.
- Receipt of any approved or authorized products intended to prevent SARS-CoV-2 infection within 6 months prior to Screening or study vaccination.
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 |
|---|---|---|
| NDV-HXP-S-KP.2Nasal Administration of a COVID-19 vaccine to compare against a commercially available mRNA vaccine | Biological | IN administration of study drug plus placebo via IM |
| COVID-19 mRNA VaccineUsed as a comparator to study vaccine | Biological | IN administration of placebo plus COVID-19 vaccine via IM |
Primary outcome
Safety and Tolerability of the NDV-HXP-S-KP.2 Vaccine Compared With an Approved mRNA COVID-19 Vaccine
Time frame: Up to 180 days after vaccination
Safety and tolerability of the NDV-HXP-S-KP.2 vaccine given intranasally and an approved mRNA COVID-19 vaccine given intramuscularly will be assessed in previously immunized adults. Outcomes include the percentage of participants with solicited local and systemic reactogenicity symptoms through 7 days, unsolicited adverse events through 30 days, and serious, medically attended, or special interest adverse events through 180 days. Clinically significant abnormal lab results (chemistry and hematology) will also be assessed through 7 days post-vaccination.
3 secondary outcomes
Percentage of Participants With Viral Vector-Related Illness or Shedding After Vaccination
Time frame: Through Day 31 post-vaccination
Humoral Immune Response to the NDV-HXP-S-KP.2 Vaccine Compared With the Comparator Vaccine
Time frame: From Day 1 through Day 181 post-vaccination
Mucosal Immune Response to the NDV-HXP-S-KP.2 Vaccine Compared With the Comparator Vaccine
Time frame: From Day 1 through Day 181 post-vaccination
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 22 Jul 2026.
- Individual participant dataSharing planned: No. IPD will only be used internally at CastleVax for evaluation of the study outcomes.
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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.
Michael Egan, PhD study chair
CastleVax Inc.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing NDV-HXP-S-KP.2 and COVID-19 mRNA Vaccine in people with COVID-19, run by CastleVax Inc. at 2 sites in United States.
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 8 inclusion and 31 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 22 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. 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?
Safety and Tolerability of the NDV-HXP-S-KP.2 Vaccine Compared With an Approved mRNA COVID-19 Vaccine (time frame: Up to 180 days after vaccination). 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 22 Jul 2026.