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NCT Number: NCT07675811

A Study to Evaluate the Efficacy and Safety of Fel d 1 Monoclonal Antibodies in Adult and Pediatric Participants With Allergic Conjunctivitis Due to Cat Allergy

This study is researching two experimental medicines, freneslerbart and mevonlerbart. Freneslerbart and mevonlerbart can be given alone or together. When given together, the medicine is called "REGN-2Cat". These medicines are also known as the "study drugs".

The aim of the study is to see what side effects freneslerbart, mevonlerbart, and REGN-2Cat may have and if they help reduce eye allergy symptoms caused by cat hair/dander compared with a placebo.

The study is looking at several other research questions, including:

* 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) * How long the study drug effect lasts

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Key information

Conditions

Allergic Conjunctivitis Conjunctival Diseases Conjunctivitis Conjunctivitis, Allergic Eye Diseases Hypersensitivity Hypersensitivity, Immediate Immune System Diseases

Age range

8 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Part A: adult participants aged 18 years and older. For part B: pediatric participants ≥8 years and <18 years, and adult participants aged 18 years and older.
  • Positive SPT to cat allergen extract
  • Positive specific Immunoglobulin E (sIgE) tests for cat and Fel d 1
  • Positive CAC criteria

Key Exclusion Criteria:

  • Significant and/or severe environmental allergies causing symptoms (eg, ocular itching, ocular redness, etc) outside of the challenge setting that are expected to coincide or may interfere with study assessments
  • Presence of any ophthalmic disease/ abnormality/ condition that may interfere with study assessments, affect the study outcomes or participant safety
  • A clinical history of asthma with treatment of asthma requiring systemic (oral or parenteral) corticosteroid treatment as defined in the protocol

Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply

Treatment and study plan

REGN-2Cat

Drug

Administered per the protocol

Other names: REGN1908-REGN1909

Freneslerbart

Drug

Administered per the protocol

Other names: REGN1908

Mevonlerbart

Drug

Administered per the protocol

Other names: REGN1909

Placebo

Drug

Administered per the protocol

Primary outcomes

  1. Ocular itch score in participants receiving REGN-2Cat as compared to placebo

    Time frame: At day 8, post-Conjunctival Allergen Challenge (CAC)

Secondary outcomes

  1. 1. Ocular itch score in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  2. 2. Conjunctival redness score in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  3. 3. Achievement of at least a 1-point reduction from baseline in ocular itch score for at least 2 out of 3 post-CAC time points in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  4. 4. Achievement of at least a 1-point reduction from baseline in conjunctival redness score for at least 2 out of 3 post-CAC time points in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  5. 5. Percent change from baseline in cat titrated Skin Prick Test (tSPT) in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85

  6. 6. Ocular itch score in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  7. 7. Conjunctival redness score in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  8. 8. Achievement of at least a 1-point reduction from baseline in ocular itch score for at least 2 out of 3 post-CAC time points in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  9. 9. Achievement of at least a 1-point reduction from baseline in conjunctival redness score for at least 2 out of 3 post-CAC time points in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  10. 10. Percent change from baseline in cat tSPT in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85

  11. 11. Ocular itch score in participants receiving mevonlerbart as compared to placebo

    Time frame: At day 8, post-CAC

    Part A

  12. 12. Conjunctival redness score in participants receiving mevonlerbart as compared to placebo

    Time frame: At day 8, post-CAC

    Part A

  13. 13. Achievement of at least a 1-point reduction from baseline in ocular itch score for at least 2 out of 3 post-CAC time points in participants receiving mevonlerbart as compared to placebo

    Time frame: At day 8, post-CAC

    Part A

  14. 14. Achievement of at least a 1-point reduction from baseline in conjunctival redness score for at least 2 out of 3 post-CAC time points in participants receiving mevonlerbart as compared to placebo

    Time frame: At day 8, post-CAC

    Part A

  15. 15. Ocular itch score in participants receiving REGN-2Cat as compared to mevonlerbart

    Time frame: At day 8, post-CAC

    Part A

  16. 16. Ocular itch score in participants receiving REGN-2Cat as compared to freneslerbart

    Time frame: At day 8, post-CAC

  17. 17. Achievements of different degrees of clinical response, as measured by change from baseline in ocular itch score among participants receiving REGN-2Cat, freneslerbart, mevonlerbart or placebo

    Time frame: At day 8, post-CAC

  18. 18. Percent change from baseline in cat tSPT in participants receiving REGN-2Cat as compared to freneslerbart

    Time frame: At day 8

  19. 19. Percent change from baseline in cat tSPT in participants receiving REGN-2Cat as compared to mevonlerbart

    Time frame: At day 8

    Part A

  20. 20. Ciliary redness score in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  21. 21. Episcleral redness score in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  22. 22. Total redness score in participants receiving REGN-2Cat as compared to placebo

    Time frame: Up to day 85, post-CAC

  23. 23. Ciliary redness score in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  24. 24. Episcleral redness score in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  25. 25. Total redness score in participants receiving freneslerbart as compared to placebo

    Time frame: Up to day 85, post-CAC

  26. 26. Percent change from baseline in cat tSPT in participants receiving mevonlerbart as compared to placebo

    Time frame: Up to day 85

    Part A

  27. 27. Occurrence of Treatment Emergent Adverse Events (TEAEs)

    Time frame: Up to day 113

  28. 28. Severity of TEAEs

    Time frame: Up to day 113

  29. 29. Occurrence of Treatment Emergent-Serious Adverse Events (TE-SAEs)

    Time frame: Up to day 113

  30. 30. Concentrations of total freneslerbart in serum

    Time frame: Up to day 113

  31. 31. Concentrations of total mevonlerbart in serum

    Time frame: Up to day 113

  32. 32. Occurrence of Anti-Drug Antibodies (ADA) to freneslerbart

    Time frame: Up to day 113

  33. 33. Magnitude of ADA to freneslerbart

    Time frame: Up to day 113

  34. 34. Occurrence of ADA to mevonlerbart

    Time frame: Up to day 113

  35. 35. Magnitude of ADA to mevonlerbart

    Time frame: Up to day 113

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Trials Administrator

CONTACT

[email protected]

844-734-6643

Sponsors and collaborators

Lead sponsor

Regeneron Pharmaceuticals

Industry

Registry information

Official study title

A Randomized, Double-Masked, Placebo-Controlled, Phase 3 Study to Assess the Efficacy and Safety of Fel d 1 Monoclonal Antibodies in Participants With Allergic Conjunctivitis Due to Cat Allergy

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Jun 30, 2026
Registry last updated
Jun 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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