A Study to Demonstrate How Well REGN1908-1909 Works in Reducing Ocular Allergy Signs and Symptoms in Adult Participants With Cat Allergy

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.

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 Overview

• Status: Completed
• Conditions: Allergic Conjunctivitis
• Intervention / Treatment: Drug: REGN1908; Drug: REGN1909; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 64
• Phase: Phase 3

Contacts and Locations

Study Locations

• Canada
  • Québec, Canada, G1V 4W2
    • Clinique de Specialisee en Allergie de la Capitale
  • Ontario
    • Kingston, Ontario, Canada, K7L 2V7
      • Kingston Health Sciences Centre
    • Ottawa, Ontario, Canada, K1H 1E4
      • Red Maple Trials Inc.
• United States
  • Massachusetts
    • Andover, Massachusetts, United States, 01810
      • Andover Eye Associates

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

1. Documented or participant-reported history of moderate to severe cat allergy for at least 2 years with bothersome ocular symptoms being near cat(s)
2. Positive SPT with cat allergen extract (mean wheal diameter at least 5 mm greater than the negative control) at screening visit 1
3. Positive Allergen-specific Immunoglobulin E (sIgE) tests for cat allergen and Fel d 1 (both ≥0.7 kUa/L) at screening visit 1
4. Must be able to complete the screening CACs to confirm moderate to severe cat allergen-induced allergic conjunctivitis as described in the protocol
5. 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:

1. Participation in a prior clinical study and received either REGN1908-1909, REGN1908, or REGN1909 antibodies as described in the protocol
2. Inability to complete or termination of the screening or confirmatory CAC (where applicable) due to a safety concern (eg, anaphylaxis), per PI judgement
3. 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
4. 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
5. 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
6. Uncontrolled asthma or on Global Initiative for Asthma (GINA) steps 4 to 5 as described in the protocol
7. Abnormal lung function as judged by the investigator with Forced expiratory volume in 1 second (FEV1) <70% of predicted at screening
8. History of cat immunotherapy (eg, subcutaneous immunotherapy or any other route) in the 3 years prior to screening visit 1
9. 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Drug: Placebo; Administered per the protocol
Experimental: REGN1908-1909	Drug: REGN1908; Administered per the protocol; Drug: REGN1909; Administered per the protocol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	At day 8 post-Conjunctival Allergen Challenge (CAC)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of serious TEAEs		Up to Day 113
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	At day 8 post-CAC
Percent change in cat titrated Skin prick test (tSPT)	Area under the curve (AUC) of the mean wheal diameters	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	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	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)	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	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	At day 8 post-CAC
Change in cat tSPT	AUC of the mean wheal diameters	Baseline and day 8
Change in cat tSPT	AUC of the mean wheal diameters	Baseline and day 113
Percent change in cat tSPT	AUC of the mean wheal diameters	Baseline and day 113
Incidence of Treatment-emergent adverse events (TEAEs)		Up to Day 113
Severity of TEAEs		Up to Day 113
Incidence of Adverse event of special interest (AESIs)		Up to Day 113
Total REGN1908 concentrations in serum over time		Up to Day 113
Total REGN1909 concentrations in serum over time		Up to Day 113
Incidence of Anti-drug antibodies (ADAs) to REGN1908		Up to Day 113
Titers of ADAs to REGN1908		Up to Day 113
Incidence of ADAs to REGN1909		Up to Day 113
Titers of ADAs to REGN1909		Up to Day 113

Collaborators and Investigators

• Sponsor: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Actual): November 6, 2024
• Primary Completion (Actual): May 10, 2025
• Study Completion (Actual): August 2, 2025

Study Registration Dates

• First Submitted: September 17, 2024
• First Submitted That Met QC Criteria: September 17, 2024
• First Posted (Actual): September 19, 2024

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Ocular allergy; Cat allergy; Ocular allergy symptoms; Ocular allergy signs; Eye allergy
• Additional Relevant MeSH Terms: Immune System Diseases; Eye Diseases; Hypersensitivity, Immediate; Hypersensitivity; Conjunctivitis; Conjunctival Diseases; Conjunctivitis, Allergic; Substandard Drugs; Pharmaceutical Preparations; Counterfeit Drugs
• Other Study ID Numbers: R1908-1909-ALG-2416

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

IPD Sharing Time Frame

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

• IPD Sharing Access Criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No