A Phase 3 interventional study of REGN1908 and REGN1909 in Allergic Conjunctivitis, sponsored by Regeneron Pharmaceuticals. Completed at 4 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-08.
Sponsored by Regeneron Pharmaceuticals · Phase 3, Interventional, and Treatment
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:
210 studies on the registry are indexed under Conjunctivitis, Allergic; 18 are open to participants now.
This study's enrollment of 64 is below the median of 87 across 174 interventional studies indexed under Conjunctivitis, Allergic.
Browse Conjunctivitis, Allergic studies →Regeneron Pharmaceuticals is the lead sponsor of 411 studies on the registry; 90 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 79 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: REGN1908 · Drug: REGN1909
Drug: Placebo
Administered per the protocol
Administered per the protocol
Administered per the protocol
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
Time frame: At day 8 post-Conjunctival Allergen Challenge (CAC)
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
Time frame: At day 8 post-CAC
Percent change in cat titrated Skin prick test (tSPT)
Area under the curve (AUC) of the mean wheal diameters
Time frame: 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
Time frame: 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
Time frame: 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)
Time frame: 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
Time frame: 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
Time frame: At day 8 post-CAC
Change in cat tSPT
AUC of the mean wheal diameters
Time frame: Baseline and day 8
Change in cat tSPT
AUC of the mean wheal diameters
Time frame: Baseline and day 113
Percent change in cat tSPT
AUC of the mean wheal diameters
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
Plan to share: Yes — All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
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
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
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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