Allergy to CatsPhase 2NCT06069063
Crossover Study of Zafirlukast in Preventing Allergen-induced Signs and Symptoms in Response to Cat Dander Challenge
A Phase 2 study testing Zafirlukast in people with Allergy to Cats, run by Allergy & Asthma Medical Group & Research Center.
Trial summary
The goal of this clinical trial is to test the hypothesis that pre-treatment with a nasal dose of Zafirlukast works well in blocking the signs and symptoms of cat dander in patients sensitive to cat dander. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Allergy to Cats
- What is being tested?
- Zafirlukast
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- No sites listed yet
- Study dates
- 5 Dec 2025to Jul 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 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Active nonsmoking males and females between the ages of 18-65 with allergic rhinitis triggered by cat dander exposure.
- Concomitant medication limited to "as needed" including for mild asthma.
- Baseline resting blood pressure les than or equal to 140/90 mm Hg.
- Baseline resting heart rate less than or equal to 100 beats/min.
- Baseline NIFR must be ≥ 50 L/min.
- Females of childbearing age may participate only if they have a negative urine pregnancy test, are non-lactating, and agree to practice an adequate birth control method (abstinence, combination barrier and spermicide, or hormonal) for the duration of the study.
- The ability to give informed consent and comply with study procedures.
Who cannot join
- Receiving immunotherapy for cat allergy
- Predictable seasonal allergy during the study period
- Newly (< 2 weeks) diagnosed with Corona Virus Disease (COVID-19)
- Regular use of controller medication for moderate to severe asthma
- Subject works with cats or keeps a cat as a pet.
- Inability or unwillingness to give written informed consent.
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- History of upper/lower respiratory tract infection, requiring systemic steroids, antibiotics, and or emergency room (ER) visit or urgent care within 6 weeks of screening visit.
- History of adverse reaction or allergy to Zafirlukast
- History of neurological, hepatic, renal, diabetic mellitus, thyroid disorder, psychiatric, addiction or other medical conditions that may interfere with the interpretation of data or the patient's participation in the study or may increase safety concerns per investigator discretion.
- History of cardiovascular diseases including uncontrolled hypertension (blood pressure >160/100 mmHg), ischemic heart disease, congestive heart failure (New York Heart Association III or IV), valvular heart disease or cardiomyopathy (e.g., depressed left ventricular ejection fraction by echo, arrhythmias).
- Known allergy or sensitivity to atropine or ipratropium bromide.
- Documented or self-reported current history of alcoholism or drug abuse.
- Baseline Spirometry Forced Expiratory Volume in first second (FEV1) <70% of predicted
- Participated in another research trial and received investigational drug within 30 days or 5 half-lives, whichever is longer
- Unwillingness or inability to comply with study procedures.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Double Blind Placebo-controlled Crossover Study of Zafirlukast in Preventing Allergen-induced Signs and Symptoms of Allergic Rhinitis in Response to Cat Dander Challenge
The goal of this clinical trial is to test the hypothesis that pre-treatment with a nasal dose of Zafirlukast works well in blocking the signs and symptoms of cat dander in patients sensitive to cat dander. The main question it aims to answer is:
- What is the difference in the symptoms of patients pre-treated with Zafirlukast and patients treated with a placebo (a look-alike substance that contains no active drug) when exposed to cat dander?
Read more
Participants will screened to see if they qualify for the study based on their reaction to being exposed to cat dander and medical history. If they qualify, they will make two more visits to the allergy center, where they will be pre-treated with either Zafirlukast or a placebo and exposed to cat dander, then observed for four hours.
Participants will
- First be screened for their medical history, the medication they take, and other factors to see if they qualify for the study.
- Participants will then be exposed to a fixed dose of cat dander to test their baseline change in TNSS. Some patients may need to return for a higher dose of cat dander.
- On the next visit, some participants will be pre-treated with Zafirlukast and the rest with a placebo, then they will be exposed to cat dander. Their symptoms will be observed.
- On the final visit, participants who were pre-treated with Zafirlukast on their last visit will be given a placebo. Participants who were pre-treated with a placebo on their last visit will be given Zafirlukast. All participants will then be exposed to cat dander and their symptoms will be observed.
Read the detailed description
The goal of this clinical trial is to test the hypothesis that pre-treatment with a nasal dose of Zafirlukast works well in blocking the signs and symptoms of cat dander in patients sensitive to cat dander. The main question it aims to answer is:
- What is the difference in the Total Nasal Symptoms Score between patients pre-treated with Zafirlukast and patients treated with a placebo (a look-alike substance that contains no active drug)?
The Total Nasal Symptom Score (TNSS; possible score of 0-12) is the sum of 4 individual subject-assessed symptom scores for
- rhinorrhea (runny nose)
- nasal congestion (stuffy nose)
- nasal itching
- sneezing
Each of these are evaluated using a scale of
- 0=None
- 1=Mild
- 2=Moderate
- 3=Severe
Participants will
- First be screened for their medical history, the medication they take, and other factors to see if they qualify for the study.
- Participants will then be exposed to a fixed dose of cat dander to test their baseline change in TNSS. Some patients may need to return for a higher dose of cat dander.
- On the next visit, some participants will be pre-treated with Zafirlukast and the rest with a placebo, then they will be exposed to cat dander. Their symptoms will be observed.
- On the final visit, participants who were pre-treated with Zafirlukast on their last visit will be given a placebo. Participants who were pre-treated with a placebo on their last visit will be given Zafirlukast. All participants will then be exposed to cat dander and their symptoms will be observed.
- Conditions
- Allergy to Cats
- Being tested
- Zafirlukast
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ZafirlukastDrug
Oral zafirlukast is approved to treat asthma and been shown in previous trials to be effective in blocking or mitigating the symptoms of people allergic to cat dander
| Study group | Role | What they receive |
|---|---|---|
| Zafirlukast cross-over to Placebo | Experimental | This group will receive the Zafirlukast pre-treatment nasally (400 mcg in 150 mcl in each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril) in the first study visit. In the second study visit, they will receive a placebo pre-treatment nasally (150 mcl each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril). Receives: Drug: Zafirlukast |
| Placebo cross-over to Zafirlukast | Experimental | This group will receive a placebo pre-treatment nasally (150 mcl each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril) in the first study visit. In the second study visit, they will receive the Zafirlukast pre-treatment nasally (400 mcg in 150 mcl in each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril). Receives: Drug: Zafirlukast |
What is being measured
The primary outcome is the main question the study is designed to answer.
Total Nasal Symptom Score (TNSS)
The Total Nasal Symptom Score (TNSS; possible score of 0-12) is the sum of 4 individual subject-assessed symptom scores for rhinorrhea, nasal congestion, nasal itching, and sneezing, each evaluated using a scale of 0=None, 1=Mild, 2=Moderate, or 3=Severe.
Measured: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
Secondary outcomes (2)
Total Ocular Symptom Score (TOSS)
The Total Ocular Symptom Score (TOSS; possible score of 0-12) is the sum of 4 individual subject-assessed symptom scores for itchiness, redness, tearing, and swelling, each evaluated using a scale of 0=None, 1=Mild, 2=Moderate, or 3=Severe.
Measured: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
Nasal Inspiratory Flow Rate (NIFR)
NIFR is an inexpensive, rapid, easy-to-use objective measure that directly measures nasal airflow during maximal inspiration. NIFR is measured in L/min.
Measured: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Oct 2023
- Study start5 Dec 2025 (estimated)
- Primary completionJun 2026 (estimated)
- Study completionJul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Allergy to CatsStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Allergy & Asthma Medical Group & Research Center
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Alex Greiner, MD, Principal investigator, Allergy & Asthma Medical Group & Research Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06069063
- Sponsor's protocol ID
- ACC001
- Status last verified
- Sep 2025
- First submitted
- 29 Sep 2023
- Last updated
- 22 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Double Blind Placebo-controlled Crossover Study of Zafirlukast in Preventing Allergen-induced Signs and Symptoms of Allergic Rhinitis in Response to Cat Dander Challenge
- ClinicalTrials.gov ID
- NCT06069063
- Acronym / sponsor ID
- ACC001
- Conditions
- Allergy to Cats
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Allergy & Asthma Medical Group & Research CenterUniversity, hospital or other
- Study start
- 5 Dec 2025 (estimated)
- Primary completion
- Jun 2026 (estimated)
- Study completion
- Jul 2026 (estimated)
- First posted
- 5 Oct 2023 (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 trial is to test the hypothesis that pre-treatment with a nasal dose of Zafirlukast works well in blocking the signs and symptoms of cat dander in patients sensitive to cat dander. The main question it aims to answer is:
- What is the difference in the symptoms of patients pre-treated with Zafirlukast and patients treated with a placebo (a look-alike substance that contains no active drug) when exposed to cat dander?
Participants will screened to see if they qualify for the study based on their reaction to being exposed to cat dander and medical history. If they qualify, they will make two more visits to the allergy center, where they will be pre-treated with either Zafirlukast or a placebo and exposed to cat dander, then observed for four hours.
Participants will
- First be screened for their medical history, the medication they take, and other factors to see if they qualify for the study.
- Participants will then be exposed to a fixed dose of cat dander to test their baseline change in TNSS. Some patients may need to return for a higher dose of cat dander.
- On the next visit, some participants will be pre-treated with Zafirlukast and the rest with a placebo, then they will be exposed to cat dander. Their symptoms will be observed.
- On the final visit, participants who were pre-treated with Zafirlukast on their last visit will be given a placebo. Participants who were pre-treated with a placebo on their last visit will be given Zafirlukast. All participants will then be exposed to cat dander and their symptoms will be observed.
Detailed description
The goal of this clinical trial is to test the hypothesis that pre-treatment with a nasal dose of Zafirlukast works well in blocking the signs and symptoms of cat dander in patients sensitive to cat dander. The main question it aims to answer is:
- What is the difference in the Total Nasal Symptoms Score between patients pre-treated with Zafirlukast and patients treated with a placebo (a look-alike substance that contains no active drug)?
The Total Nasal Symptom Score (TNSS; possible score of 0-12) is the sum of 4 individual subject-assessed symptom scores for
- rhinorrhea (runny nose)
- nasal congestion (stuffy nose)
- nasal itching
- sneezing
Each of these are evaluated using a scale of
- 0=None
- 1=Mild
- 2=Moderate
- 3=Severe
Participants will
- First be screened for their medical history, the medication they take, and other factors to see if they qualify for the study.
- Participants will then be exposed to a fixed dose of cat dander to test their baseline change in TNSS. Some patients may need to return for a higher dose of cat dander.
- On the next visit, some participants will be pre-treated with Zafirlukast and the rest with a placebo, then they will be exposed to cat dander. Their symptoms will be observed.
- On the final visit, participants who were pre-treated with Zafirlukast on their last visit will be given a placebo. Participants who were pre-treated with a placebo on their last visit will be given Zafirlukast. All participants will then be exposed to cat dander and their symptoms will be observed.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Zafirlukast cross-over to Placebo | Experimental | Drug: ZafirlukastThis group will receive the Zafirlukast pre-treatment nasally (400 mcg in 150 mcl in each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril) in the first study visit. In the second study visit, they will receive a placebo pre-treatment nasally (150 mcl each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril). |
| Placebo cross-over to Zafirlukast | Experimental | Drug: ZafirlukastThis group will receive a placebo pre-treatment nasally (150 mcl each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril) in the first study visit. In the second study visit, they will receive the Zafirlukast pre-treatment nasally (400 mcg in 150 mcl in each nostril) once before the allergen challenge (0.87mcg Fel d1 in 100mcl in each nostril). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Active nonsmoking males and females between the ages of 18-65 with allergic rhinitis triggered by cat dander exposure.
- Concomitant medication limited to "as needed" including for mild asthma.
- Baseline resting blood pressure les than or equal to 140/90 mm Hg.
- Baseline resting heart rate less than or equal to 100 beats/min.
- Baseline NIFR must be ≥ 50 L/min.
Key exclusion criteria (15 listed)
- Receiving immunotherapy for cat allergy
- Predictable seasonal allergy during the study period
- Newly (< 2 weeks) diagnosed with Corona Virus Disease (COVID-19)
- Regular use of controller medication for moderate to severe asthma
- Subject works with cats or keeps a cat as a pet.
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 |
|---|---|---|
| ZafirlukastOral zafirlukast is approved to treat asthma and been shown in previous trials to be effective in blocking or mitigating the symptoms of people allergic to cat dander | Drug | Placebo cross-over to Zafirlukast, Zafirlukast cross-over to Placebo |
Primary outcome
Total Nasal Symptom Score (TNSS)
Time frame: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
The Total Nasal Symptom Score (TNSS; possible score of 0-12) is the sum of 4 individual subject-assessed symptom scores for rhinorrhea, nasal congestion, nasal itching, and sneezing, each evaluated using a scale of 0=None, 1=Mild, 2=Moderate, or 3=Severe.
2 secondary outcomes
Total Ocular Symptom Score (TOSS)
Time frame: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
Nasal Inspiratory Flow Rate (NIFR)
Time frame: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.
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 Sep 2025.
- Individual participant dataSharing planned: No
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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.
Alex Greiner, MD principal investigator
Allergy & Asthma Medical Group & Research Center
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Zafirlukast in people with Allergy to Cats, run by Allergy & Asthma Medical Group & Research Center.
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 7 inclusion and 15 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: opening soon, as of the sponsor's last update on 22 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
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?
Contact Teresa Lloyd, BSRT (858-268-2368 ext. 143, teresalloyd@allergyandasthma.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Total Nasal Symptom Score (TNSS) (time frame: Starts at 10 minutes after the cat allergen challenge, then 30, 60, 120, and 240 minutes after.). 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 Sep 2025.