An Extension Study to Investigate the Long-term Safety and Tolerability of Itepekimab in Adult Participants With Inadequately Controlled Chronic Rhinosinusitis With Nasal Polyps (CEREN-3)

A Double-blinded Extension Study to Evaluate the Long-term Safety and Tolerability of Itepekimab in Adult Participants With Inadequately Controlled Chronic Rhinosinusitis With Nasal Polyps (CRSwNP) Who Participated in Either EFC18418 or EFC18419 Clinical Studies

This is a double-blind, parallel-group, Phase 3, 2-arm study that is designed to provide additional safety information, assess the durability of treatment response, and provide additional PK and immunogenicity assessments.

The primary purpose of this study is to evaluate safety and tolerability of both new or continued treatment with itepekimab 300 mg SC high dose or itepekimab 300 mg SC low dose in participants with CRSwNP having completed the intervention period of the clinical studies EFC18418 or EFC18419. A secondary purpose of this study is to provide efficacy outcomes beyond the intervention period of the parent trials EFC18418 and EFC18419.

Study details include:

• The study duration will be up to 72 weeks.
• The intervention duration will be 52 weeks.
• A follow-up period of 20 weeks will be conducted.
• The number of visits will be 8 and the number of phone contacts will be 4.

Study Overview

• Status: Enrolling by invitation
• Conditions: Chronic Rhinosinusitis With Nasal Polyps
• Intervention / Treatment: Drug: Itepekimab (SAR440340); Drug: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 380
• Phase: Phase 3

Contacts and Locations

Study Locations

• Australia
  • Western Australia
    • Spearwood, Western Australia, Australia, 6163
      • Investigational Site Number : 0362001
• Canada
  • Quebec
    • Québec, Quebec, Canada, G1V 4G5
      • Investigational Site Number : 1241001
• Chile
  • Maule Region
    • Talca, Maule Region, Chile, 3465584
      • Investigational Site Number : 1521003
  • Reg Metropolitana de Santiago
    • Santiago, Reg Metropolitana de Santiago, Chile, 7500505
      • Investigational Site Number : 1522003
    • Santiago, Reg Metropolitana de Santiago, Chile, 7500692
      • Investigational Site Number : 1521002
• China
  • Beijing, China, 100730
    • Investigational Site Number : 1562001
  • Chengdu, China, 610017
    • Investigational Site Number : 1562004
  • Jingzhou, China, 434020
    • Investigational Site Number : 1562008
  • Shenyang, China, 110004
    • Investigational Site Number : 1562006
  • Taiyuan, China, 030001
    • Investigational Site Number : 1562010
• South Korea
  • Seoul-teukbyeolsi
    • Seoul, Seoul-teukbyeolsi, South Korea, 07061
      • Investigational Site Number : 4101001
• United Kingdom
  • Bradford, United Kingdom, BD9 6RJ
    • Investigational Site Number : 8261004
  • Lancashire
    • Wigan, Lancashire, United Kingdom, Wn6 9ep
      • Investigational Site Number : 8262002
• United States
  • California
    • La Mesa, California, United States, 91942
      • Velocity Clinical Research - San Diego- Site Number : 8402041
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73120
      • Allergy, Asthma and Clinical Research- Site Number : 8402002

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participants with CRSwNP who completed the 52-weeks intervention period in a previous itepekimab CRSwNP Phase 3 clinical study (ie, EFC18418 or EFC18419) and for which an EOT visit occurred no later than 5 days before the enrollment visit of this study.

• A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies:

  • Is not a women of childbearing potential (WOCBP), OR
  • Is a WOCBP who agrees to follow the contraceptive guidance during the intervention period and for at least 20 weeks after the last dose of study intervention.

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

• Diagnosis of a malignancy during parent study, except a squamous or basal cell carcinoma of the skin.
• Any opportunistic infection during the parent study, such as tuberculosis (TB) or other infections whose nature or course may suggest an immunocompromised status.
• Anaphylactic reactions or systemic allergic reactions that are related to IMP and require treatment during the parent study.
• Any other situation that led to a permanent premature IMP discontinuation in parent trials.

The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Itepekimab high dose; Subcutaneous (SC) administration of Itepekimab high dose for 52 weeks	Drug: Itepekimab (SAR440340); Pharmaceutical form: Solution for injection in prefilled syringe. Route of administration: Subcutaneous; Other Names: REGN3500
Experimental: Itepekimab low dose; SC administration of Itepekimab low dose for 52 weeks	Drug: Itepekimab (SAR440340); Pharmaceutical form: Solution for injection in prefilled syringe. Route of administration: Subcutaneous; Other Names: REGN3500; Drug: Placebo; Pharmaceutical form: Solution for injection in prefilled syringe. Route of administration: Subcutaneous

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of treatment-emergent adverse events (AEs), adverse events of special interest (AESIs), serious adverse events (SAEs), AEs leading to death, and AEs leading to permanent treatment discontinuation	All AEs (serious or nonserious) will be collected from the signing of the ICF until end of study (EOS) visit	Baseline to EOS (Week 72)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Annualized rate of SCS course or surgery for CRS		Baseline up to Week 52
Change from baseline of the parent studies (EFC18418, EFC18419) in endoscopic NPS	The Nasal Polyp Score (NPS) is the sum of the right and left nostril scores, as evaluated by means of nasal endoscopy. Nasal polyp is graded based on polyp size from 0 to 4 with higher scores indicating larger polyps. The sum of right and left nostril scores ranges from 0 (no polyps) to 8 (large polyps).	Baseline to Week 52
Change from baseline of the parent studies (EFC18418, EFC18419) in NCS	The Nasal Congestion Score (NCS) is scored using a 0 to 3 categorical scale where 0 = no symptoms, 1 = mild symptoms, 2 = moderate symptoms and 3 = severe symptoms.	Baseline to EOS (Week 72)
Functional itepekimab concentration in serum		Baseline to EOS (Week 72)
Incidence of treatment-emergent anti-drug antibody (ADA) responses		Baseline to EOS (Week 72)
Proportion of participants with CRSwNP requiring systemic corticosteroid(s) (SCS) or surgery for chronic rhinosinusitis (CRS)		Baseline up to Week 52

Collaborators and Investigators

• Sponsor: Sanofi
• Collaborators: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Sciences & Operations, Sanofi

Publications and helpful links

Helpful Links

• LTS18420 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): March 12, 2026
• Primary Completion (Estimated): December 12, 2028
• Study Completion (Estimated): December 12, 2028

Study Registration Dates

• First Submitted: February 13, 2026
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 20, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 24, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: itepekimab
• Other Study ID Numbers: LTS18420; 2025-522983-33 (Registry Identifier: CTIS); U1111-1320-4430 (Registry Identifier: ICTRP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Drug and device information, study documents

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