Allergic ConjunctivitisPhase 3NCT06602726
A Study to Demonstrate How Well REGN1908-1909 Works in Reducing Ocular Allergy Signs and Symptoms in Adult Participants With Cat Allergy
A Phase 3 study testing REGN1908 and REGN1909 in people with Allergic Conjunctivitis, run by Regeneron Pharmaceuticals at 4 sites in 2 countries.
Trial summary
This study is researching 2 experimental drugs, REGN1908 and REGN1909, which are called REGN1908-1909 when mixed together (called "study drug") to reduce eye allergy signs and symptoms from cat allergy. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Allergic Conjunctivitis
- What is being tested?
- REGN1908 and REGN1909
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 64 participants
- Where
- 4 sitesin 2 countries
- Study dates
- 6 Nov 2024to 2 Aug 2025
- Phase
- Phase 3
- Are there results?
- None posted in the registry
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
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Documented or participant-reported history of moderate to severe cat allergy for at least 2 years with bothersome ocular symptoms being near cat(s)
- Positive SPT with cat allergen extract (mean wheal diameter at least 5 mm greater than the negative control) at screening visit 1
- Positive Allergen-specific Immunoglobulin E (sIgE) tests for cat allergen and Fel d 1 (both ≥0.7 kUa/L) at screening visit 1
- Must be able to complete the screening CACs to confirm moderate to severe cat allergen-induced allergic conjunctivitis as described in the protocol
- Must not have lived with a cat(s) in the home for the past 3 years and must be willing to have no exposure to cat(s) at home throughout the study duration as described in the protocol
Who cannot join
- Participation in a prior clinical study and received either REGN1908-1909, REGN1908, or REGN1909 antibodies as described in the protocol
- Inability to complete or termination of the screening or confirmatory CAC (where applicable) due to a safety concern (eg, anaphylaxis), per PI judgement
- Significant and/or severe allergies, ocular, nasal, or systemic disease causing symptoms (eg, ocular itching, ocular redness, etc) that are expected to coincide or potentially interfere with the study CAC assessments, as described in the protocol
- Persistent chronic or recurring acute infection requiring treatment with systemic antibiotics, antivirals, or antifungals, or any untreated respiratory infections within 4 weeks prior to screening visit 1 as described in the protocol
- Presence of ocular conditions associated with acute or chronic vision loss, or any other ophthalmic disease or abnormality that may affect the study outcomes or participant safety, per Principal Investigator (PI) judgement as described in the protocol
- Uncontrolled asthma or on Global Initiative for Asthma (GINA) steps 4 to 5 as described in the protocol
Show all 10Show fewer
- Abnormal lung function as judged by the investigator with Forced expiratory volume in 1 second (FEV1) <70% of predicted at screening
- History of cat immunotherapy (eg, subcutaneous immunotherapy or any other route) in the 3 years prior to screening visit 1
- Ongoing Allergen immunotherapy (AIT) with any allergen other than cat at screening visit 1 as described in the protocol
- Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply
Trial locations and contacts
4 sites in 2 countries.
4 sites in 2 countries
Canada3 sites
Kingston Health Sciences Centre
Kingston, Ontario, K7L 2V7
Red Maple Trials Inc.
Ottawa, Ontario, K1H 1E4
Clinique de Specialisee en Allergie de la Capitale
Québec, G1V 4W2
United States1 site
Andover Eye Associates
Andover, Massachusetts, 01810
About this study
Official title: A Randomized, Double-masked, Placebo-controlled Study to Assess the Efficacy and Safety of REGN1908-1909 to Reduce Signs and Symptoms of Allergic Conjunctivitis in Participants With Cat Allergy
This study is researching 2 experimental drugs, REGN1908 and REGN1909, which are called REGN1908-1909 when mixed together (called "study drug") to reduce eye allergy signs and symptoms from cat allergy.
The aim of the study is to see how safe and effective the study drug is at lowering allergic eye signs and symptoms compared with placebo. A placebo looks like a treatment but does not contain any real medicine.
Read more
The study is looking at several other research questions, including:
- What side effects may happen from taking the study drug
- How much study drug is in the blood at different times
- Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)
- Conditions
- Allergic Conjunctivitis
- Being tested
- REGN1908, REGN1909, Placebo
- Keywords
- Cat allergy, Eye allergy, Ocular allergy, Ocular allergy symptoms, Ocular allergy signs
- Medical subject headings
- Conjunctivitis, Allergic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
REGN1908Drug
Administered per the protocol
REGN1909Drug
Administered per the protocol
PlaceboDrug
Administered per the protocol
| Study group | Role | What they receive |
|---|---|---|
| REGN1908-1909 | Experimental | Not described Receives: Drug: REGN1908; Drug: REGN1909 |
| Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ocular itch score
Assessed using the Ora Calibra® Conjunctival Allergen Challenge Ocular Itching Scale, a 0-4 point scale where 0= none and 4= incapacitating itch, 0.5 unit increments
Measured: At day 8 post-Conjunctival Allergen Challenge (CAC)
Secondary outcomes (20)
Conjunctival redness score
Assessed using the Ora Calibra® Hyperemia Scale (for conjunctival [conjunctival redness scale], ciliary [ciliary redness scale] and episcleral [episcleral redness scale] vessel beds), a 0 to 4 point scale, where 0 = none and 4 = extremely severe, 0.5 unit increments
Measured: At day 8 post-CAC
Percent change in cat titrated Skin prick test (tSPT)
Area under the curve (AUC) of the mean wheal diameters
Measured: Baseline and day 8
Tearing score
Assessed using the Ora Calibra® Conjunctival Allergen Challenge Tearing Scale, a 0-4 scale where 0 = none and 4 = very severe, 1 unit increments
Measured: At day 8 post-CAC
Total Ocular Symptom Score (TOSS)
TOSS is a summed score of ocular itch score (graded 0 = none to 4 = incapacitating itch), conjunctival redness score (graded 0 = none to 4 = extremely severe), and tearing score (graded 0 = none to 4 = very severe) for a total range from 0 to 12, where higher scores indicate worse responses
Measured: At day 8 post-CAC
Total redness score
The total redness score is calculated for CAC: range 0 to 12, where higher scores indicate worse responses (calculated as a sum of the bilateral averages for conjunctival redness score, graded 0 = none to 4 = extremely severe + ciliary redness score, graded 0 = none and 4 = extremely severe + episcleral redness score, graded 0 = none and 4 = extremely severe)
Measured: At day 8 post-CAC
Ciliary redness score
Assessed using the Ora Calibra® Hyperemia Scale (for conjunctival [conjunctival redness scale], ciliary [ciliary redness scale] and episcleral [episcleral redness scale] vessel beds), a 0 to 4 point scale, where 0 = none and 4 = extremely severe, 0.5 unit increments
Measured: At day 8 post-CAC
Episcleral redness score
Assessed using the Ora Calibra® Hyperemia Scale (for conjunctival [conjunctival redness scale], ciliary [ciliary redness scale] and episcleral [episcleral redness scale] vessel beds), a 0 to 4 point scale, where 0 = none and 4 = extremely severe, 0.5 unit increments
Measured: At day 8 post-CAC
Change in cat tSPT
AUC of the mean wheal diameters
Measured: Baseline and day 8
Change in cat tSPT
AUC of the mean wheal diameters
Measured: Baseline and day 113
Percent change in cat tSPT
AUC of the mean wheal diameters
Measured: Baseline and day 113
Incidence of Treatment-emergent adverse events (TEAEs)
Measured: Up to Day 113
Severity of TEAEs
Measured: Up to Day 113
Incidence of serious TEAEs
Measured: Up to Day 113
Incidence of Adverse event of special interest (AESIs)
Measured: Up to Day 113
Total REGN1908 concentrations in serum over time
Measured: Up to Day 113
Total REGN1909 concentrations in serum over time
Measured: Up to Day 113
Incidence of Anti-drug antibodies (ADAs) to REGN1908
Measured: Up to Day 113
Titers of ADAs to REGN1908
Measured: Up to Day 113
Incidence of ADAs to REGN1909
Measured: Up to Day 113
Titers of ADAs to REGN1909
Measured: Up to Day 113
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Sep 2024
- Study start6 Nov 2024
- Primary completion10 May 2025
- Study completion2 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Allergic ConjunctivitisStudies of the same condition, open and under way.
- More trials run by Regeneron PharmaceuticalsThe sponsor's other registered studies.
- 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 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 64 participants (actual)
Sponsor and investigators
- Lead sponsor
- Regeneron Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Clinical Trial Management, Study director, Regeneron Pharmaceuticals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06602726
- Sponsor's protocol ID
- R1908-1909-ALG-2416
- Status last verified
- Apr 2026
- First submitted
- 17 Sep 2024
- Last updated
- 8 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-masked, Placebo-controlled Study to Assess the Efficacy and Safety of REGN1908-1909 to Reduce Signs and Symptoms of Allergic Conjunctivitis in Participants With Cat Allergy
- ClinicalTrials.gov ID
- NCT06602726
- Acronym / sponsor ID
- R1908-1909-ALG-2416
- Conditions
- Allergic Conjunctivitis
- Keywords
- Cat allergy, Eye allergy, Ocular allergy, Ocular allergy symptoms, Ocular allergy signs
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 64 participants (actual)
- Lead sponsor
- Regeneron PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 6 Nov 2024 (actual)
- Primary completion
- 10 May 2025 (actual)
- Study completion
- 2 Aug 2025 (actual)
- First posted
- 19 Sep 2024 (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.
This study is researching 2 experimental drugs, REGN1908 and REGN1909, which are called REGN1908-1909 when mixed together (called "study drug") to reduce eye allergy signs and symptoms from cat allergy.
The aim of the study is to see how safe and effective the study drug is at lowering allergic eye signs and symptoms compared with placebo. A placebo looks like a treatment but does not contain any real medicine.
The study is looking at several other research questions, including:
- What side effects may happen from taking the study drug
- How much study drug is in the blood at different times
- Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| REGN1908-1909 | Experimental | Drug: REGN1908, Drug: REGN1909 |
| Placebo | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Documented or participant-reported history of moderate to severe cat allergy for at least 2 years with bothersome ocular symptoms being near cat(s)
- Positive SPT with cat allergen extract (mean wheal diameter at least 5 mm greater than the negative control) at screening visit 1
- Positive Allergen-specific Immunoglobulin E (sIgE) tests for cat allergen and Fel d 1 (both ≥0.7 kUa/L) at screening visit 1
- Must be able to complete the screening CACs to confirm moderate to severe cat allergen-induced allergic conjunctivitis as described in the protocol
- Must not have lived with a cat(s) in the home for the past 3 years and must be willing to have no exposure to cat(s) at home throughout the study duration as described in the protocol
Key exclusion criteria (10 listed)
- Participation in a prior clinical study and received either REGN1908-1909, REGN1908, or REGN1909 antibodies as described in the protocol
- Inability to complete or termination of the screening or confirmatory CAC (where applicable) due to a safety concern (eg, anaphylaxis), per PI judgement
- Significant and/or severe allergies, ocular, nasal, or systemic disease causing symptoms (eg, ocular itching, ocular redness, etc) that are expected to coincide or potentially interfere with the study CAC assessments, as described in the protocol
- Persistent chronic or recurring acute infection requiring treatment with systemic antibiotics, antivirals, or antifungals, or any untreated respiratory infections within 4 weeks prior to screening visit 1 as described in the protocol
- Presence of ocular conditions associated with acute or chronic vision loss, or any other ophthalmic disease or abnormality that may affect the study outcomes or participant safety, per Principal Investigator (PI) judgement as described in the protocol
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 |
|---|---|---|
| REGN1908Administered per the protocol | Drug | REGN1908-1909 |
| REGN1909Administered per the protocol | Drug | REGN1908-1909 |
| PlaceboAdministered per the protocol | Drug | Placebo |
Primary outcome
Ocular itch score
Time frame: At day 8 post-Conjunctival Allergen Challenge (CAC)
Assessed using the Ora Calibra® Conjunctival Allergen Challenge Ocular Itching Scale, a 0-4 point scale where 0= none and 4= incapacitating itch, 0.5 unit increments
20 secondary outcomes
Conjunctival redness score
Time frame: At day 8 post-CAC
Percent change in cat titrated Skin prick test (tSPT)
Time frame: Baseline and day 8
Tearing score
Time frame: At day 8 post-CAC
Total Ocular Symptom Score (TOSS)
Time frame: At day 8 post-CAC
Total redness score
Time frame: At day 8 post-CAC
Ciliary redness score
Time frame: At day 8 post-CAC
Episcleral redness score
Time frame: At day 8 post-CAC
Change in cat tSPT
Time frame: Baseline and day 8
Change in cat tSPT
Time frame: Baseline and day 113
Percent change in cat tSPT
Time frame: Baseline and day 113
Incidence of Treatment-emergent adverse events (TEAEs)
Time frame: Up to Day 113
Severity of TEAEs
Time frame: Up to Day 113
Incidence of serious TEAEs
Time frame: Up to Day 113
Incidence of Adverse event of special interest (AESIs)
Time frame: Up to Day 113
Total REGN1908 concentrations in serum over time
Time frame: Up to Day 113
Total REGN1909 concentrations in serum over time
Time frame: Up to Day 113
Incidence of Anti-drug antibodies (ADAs) to REGN1908
Time frame: Up to Day 113
Titers of ADAs to REGN1908
Time frame: Up to Day 113
Incidence of ADAs to REGN1909
Time frame: Up to Day 113
Titers of ADAs to REGN1909
Time frame: Up to Day 113
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Individual participant dataSharing planned: Yes. All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
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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.
Clinical Trial Management study director
Regeneron Pharmaceuticals
4 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing REGN1908 and REGN1909 in people with Allergic Conjunctivitis, run by Regeneron Pharmaceuticals at 4 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 5 inclusion and 10 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: finished, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in Canada, 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. Some participants in this study may receive a placebo. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Ocular itch score (time frame: At day 8 post-Conjunctival Allergen Challenge (CAC)). 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 8 May 2026; AzTrials last refreshed its copy on 30 Oct 2026.