Long-term Safety and Efficacy Evaluation of Subcutaneous Amlitelimab in Adult Participants With Moderate-to-severe Asthma Who Completed Treatment Period of Previous Amlitelimab Asthma Clinical Study (RIVER-ASTHMA)

A Long-term Extension Study to Evaluate the Long-term Safety, Tolerability, and Efficacy of Subcutaneous Amlitelimab in Adult Participants With Moderate-to-severe Asthma Who Completed Treatment Period of Previous Amlitelimab Asthma Clinical Study

This is a study of amlitelimab for the treatment of participants with moderate-to-severe asthma. The study will have a double-blind treatment period until Week 24 for each participant and an open-label treatment period where each participant will receive open-label amlitelimab from Week 24 onwards. The purpose of this study is to evaluate long-term safety, tolerability, and efficacy of amlitelimab for the treatment of adult participants with moderate-to-severe asthma who have previously been enrolled and completed the treatment period of the parent study. The study duration will be up to 156 weeks. The treatment duration will be up to 144 weeks. The number of visits will be 18.

Study Overview

• Status: Active, not recruiting
• Conditions: Asthma
• Intervention / Treatment: Drug: Amlitelimab; Drug: Placebo

Detailed Description

The duration of the study for each participant will be up to 156 weeks.

• Study Type: Interventional
• Enrollment (Actual): 335
• Phase: Phase 2

Contacts and Locations

Study Locations

• Argentina
  • Buenos Aires, Argentina, 1425
    • Investigational Site Number : 0320001
  • Buenos Aires, Argentina, 1121
    • Investigational Site Number : 0320004
  • Buenos Aires, Argentina, 1414
    • Investigational Site Number : 0320003
  • Buenos Aires, Argentina, 1425
    • Investigational Site Number : 0320002
  • Buenos Aires, Argentina, 1650
    • Investigational Site Number : 0320009
  • Buenos Aires
    • La Plata, Buenos Aires, Argentina, 1900
      • Investigational Site Number : 0320008
  • Santa Fe Province
    • Rosario, Santa Fe Province, Argentina, 2000
      • Investigational Site Number : 0320006
    • Rosario, Santa Fe Province, Argentina, 2000
      • Investigational Site Number : 0320007
    • Rosario, Santa Fe Province, Argentina, 2000
      • Investigational Site Number : 0320005
• Brazil
  • São Paulo, Brazil, 05403-000
    • Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo- Site Number : 0760008
  • Espírito Santo
    • Vitória, Espírito Santo, Brazil, 29055-450
      • Centro de Diagnostico e Pesquisa da Osteoporose do Espirito Santo- Site Number : 0760002
  • Estado de Bahia
    • Salvador, Estado de Bahia, Brazil, 40060-330
      • Associacao Proar- Site Number : 0760004
  • Rio Grande do Sul
    • Passo Fundo, Rio Grande do Sul, Brazil, 99010-170
      • Instituto Méderi de Pesquisa e Saúde- Site Number : 0760001
    • Porto Alegre, Rio Grande do Sul, Brazil, 90020-090
      • Irmandade da Santa Casa de Misericórdia de Porto Alegre- Site Number : 0760007
    • Porto Alegre, Rio Grande do Sul, Brazil, 90610-000
      • Hospital São Lucas da PUCRS - Porto Alegre - Avenida Ipiranga- Site Number : 0760006
  • São Paulo
    • Sorocaba, São Paulo, Brazil, 18040-425
      • Clinica de Alergia Martti Antila- Site Number : 0760003
• Canada
  • Ontario
    • Ottawa, Ontario, Canada, K1G 6C6
      • Investigational Site Number : 1240008
  • Quebec
    • Trois-Rivières, Quebec, Canada, G8T 7A1
      • Investigational Site Number : 1240007
• Chile
  • Maule Region
    • Talca, Maule Region, Chile, 3465584
      • Investigational Site Number : 1520006
  • Reg Metropolitana de Santiago
    • Santiago, Reg Metropolitana de Santiago, Chile, 7500692
      • Investigational Site Number : 1520001
    • Santiago, Reg Metropolitana de Santiago, Chile, 7750495
      • Investigational Site Number : 1520003
    • Santiago, Reg Metropolitana de Santiago, Chile, 8380465
      • Investigational Site Number : 1520008
  • Valparaiso
    • Quillota, Valparaiso, Chile, 2260877
      • Investigational Site Number : 1520005
• Hungary
  • Edelény, Hungary, 3780
    • Investigational Site Number : 3480009
  • Gödöllő, Hungary, 2100
    • Investigational Site Number : 3480011
  • Püspökladány, Hungary, 4150
    • Investigational Site Number : 3480006
  • Százhalombatta, Hungary, 2440
    • Investigational Site Number : 3480012
• Italy
  • Verona, Italy, 37134
    • Investigational Site Number : 3800001
  • Napoli
    • Naples, Napoli, Italy, 80131
      • Investigational Site Number : 3800004
  • Roma
    • Rome, Roma, Italy, 00168
      • Investigational Site Number : 3800003
• Japan
  • Hiroshima, Japan, 732-0052
    • Investigational Site Number : 3920019
  • Tokyo, Japan, 140-8522
    • Investigational Site Number : 3920001
  • Tokyo, Japan, 103-0027
    • Investigational Site Number : 3920005
  • Osaka
    • Sakai, Osaka, Japan, 591-8555
      • Investigational Site Number : 3920010
  • Tokyo
    • Chūō, Tokyo, Japan, 104-0031
      • Investigational Site Number : 3920004
• Mexico
  • Chihuahua City, Mexico, 31000
    • Investigational Site Number : 4840002
  • Jalisco
    • Guadalajara, Jalisco, Mexico, 44100
      • Investigational Site Number : 4840001
    • Guadalajara, Jalisco, Mexico, 44670
      • Investigational Site Number : 4840005
  • Yucatán
    • Mérida, Yucatán, Mexico, 97070
      • Investigational Site Number : 4840008
• Poland
  • Elblag, Poland, 82-300
    • Investigational Site Number : 6160003
  • Greater Poland Voivodeship
    • Poznan, Greater Poland Voivodeship, Poland, 60-693
      • Investigational Site Number : 6160001
  • Lesser Poland Voivodeship
    • Krakow, Lesser Poland Voivodeship, Poland, 31-209
      • Investigational Site Number : 6160006
    • Tarnów, Lesser Poland Voivodeship, Poland, 33-100
      • Investigational Site Number : 6160007
  • Podlaskie Voivodeship
    • Bialystok, Podlaskie Voivodeship, Poland, 15-044
      • Investigational Site Number : 6160004
  • Pomeranian Voivodeship
    • Gdansk, Pomeranian Voivodeship, Poland, 80-405
      • Investigational Site Number : 6160002
• South Africa
  • Benoni, South Africa, 1500
    • Investigational Site Number : 7100007
  • Cape Town, South Africa, 7530
    • Investigational Site Number : 7100002
  • Cape Town, South Africa, 7700
    • Investigational Site Number : 7100001
  • Middelburg, South Africa, 1055
    • Investigational Site Number : 7100004
• South Korea
  • Gyeongsangbuk-do
    • Daegu, Gyeongsangbuk-do, South Korea, 42415
      • Investigational Site Number : 4100004
  • Seoul-teukbyeolsi
    • Seoul, Seoul-teukbyeolsi, South Korea, 05505
      • Investigational Site Number : 4100002
    • Seoul, Seoul-teukbyeolsi, South Korea, 03722
      • Investigational Site Number : 4100001
    • Seoul, Seoul-teukbyeolsi, South Korea, 05030
      • Investigational Site Number : 4100005
    • Seoul, Seoul-teukbyeolsi, South Korea, 06591
      • Investigational Site Number : 4100006
• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye), 34098
    • Investigational Site Number : 7920001
  • Izmir, Turkey (Türkiye), 35100
    • Investigational Site Number : 7920003
  • Kayseri, Turkey (Türkiye), 38039
    • Investigational Site Number : 7920008
  • Mersin, Turkey (Türkiye), 33070
    • Investigational Site Number : 7920002
  • İzmit, Turkey (Türkiye), 41001
    • Investigational Site Number : 7920005
• United Kingdom
  • Bradford, United Kingdom, BD9 6RJ
    • Investigational Site Number : 8260001
• United States
  • California
    • Stockton, California, United States, 95207
      • Bensch Research Associates- Site Number : 8400004
  • Florida
    • Boynton Beach, Florida, United States, 33435
      • Helix Biomedics- Site Number : 8400029
    • Miami Lakes, Florida, United States, 33014
      • Savin Medical Group - Miami Lakes- Site Number : 8400015
    • Pembroke Pines, Florida, United States, 33025
      • Pines Care Research Center- Site Number : 8400028
  • Idaho
    • Boise, Idaho, United States, 83706
      • Treasure Valley Medical Research- Site Number : 8400031
  • Maryland
    • Baltimore, Maryland, United States, 21224
      • Johns Hopkins Bayview Medical Center- Site Number : 8400012
  • Oklahoma
    • Edmond, Oklahoma, United States, 73034
      • OK Clinical Research- Site Number : 8400001
  • Texas
    • Boerne, Texas, United States, 78006
      • South Texas Medical Research Institute - TTS Research- Site Number : 8400011

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participants with moderate-to-severe asthma who completed the treatment period of the parent study per protocol
• Participants on background dose with medium-to-high doses of ICS therapy (≥500 µg of fluticasone propionate daily or comparable ICS dosage up to a maximum of 2000 µg/day of fluticasone propionate or clinically comparable) in combination with a second or third controller (eg, LABA, LTRA, LAMA, methylxanthines), with or without OCS (up to a maximum of 15 mg prednisone or equivalent daily or 30 mg every other day) as maintained during the parent study in which they participated Note for Japan: participants must be on ≥400 μg of fluticasone propionate daily or equivalent.
• Contraception for male and female participants;

For female participants:

• incapable of becoming pregnant
• not pregnant or breast feeding
• not to donate or cryopreserve eggs for female participants For male participants
• No sperm donation or cryopreserving sperms

Exclusion Criteria:

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

• Chronic lung disease other than asthma
• Participants who developed a new medical condition or a change in status of an established medical condition or require a new treatment or medication prior to enrollment, which (per Investigator's medical judgment) would adversely affect the participation in this study or would require permanent IMP discontinuation
• Current smoker or active vaping of any products and/or marijuana smoking
• Prescription drug or substance abuse, including alcohol, considered significant by the Investigator
• Any new development with the participant's disease or condition or any significant laboratory test abnormality during the parent study that, in the opinion of the Investigator, may present an unreasonable risk for the participant
• Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the Investigator, contraindicates participation in the study
• Individuals accommodated in an institution because of regulatory or legal order; prisoners or participants who are legally institutionalized
• Participant not suitable for participation, whatever the reason, as judged by the Investigator, including medical or clinical conditions, or participants potentially at risk of noncompliance to study procedures
• Participants are employees of the investigative site or other individuals directly involved in the conduct of the study, or immediate family members of such individuals

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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Treatment group 1; Subcutaneous Injection as per protocol	Drug: Amlitelimab; Injection Solution: by subcutaneous injection (SCI)
Experimental: Treatment group 2; Subcutaneous injection as per protocol	Drug: Placebo; Injection Solution: by subcutaneous injection (SCI)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants with treatment-emergent adverse events	Percentage of participants with treatment emergent Adverse Events.	From baseline up to Week 156 (EOS of LTS17510)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from parent study baseline in prebronchodilator (BD) and post-BD forced expiratory volume in 1 second (FEV1) at each spirometry endpoint		From baseline of parent study up to week 144 (EOT of LTS17510)
Change from LTS17510 study baseline in pre bronchodilator (BD) and post-BD forced expiratory volume in 1 second (FEV1) at each spirometry endpoint		From baseline of LTS17510 study up to week 144 (EOT of LTS17510)
Change from parent study baseline in pre-BD and post-BD peak expiratory flow [PEF] at each spirometry endpoint		From baseline of parent study up to Week 144 (EOT of LTS17510)
Change from LTS17510 study baseline in pre-BD and post-BD peak expiratory flow [PEF] at each spirometry endpoint		From baseline of LTS17510 study up to Week 144 (EOT of LTS17510)
Change from parent study baseline in Pre-BD and post-BD forced vital capacity [FVC] at each spirometry endpoint		From baseline of parent study up to Week 144 (EOT of LTS17510)
Change from LTS17510 study Baseline in Pre-BD and post-BD forced vital capacity [FVC] at each spirometry endpoint		From baseline of lTS17510 study up to Week 144 (EOT of LTS17510)
Change from parent study baseline in pre-BD and post-BD forced expiratory flow [FEF] 25% to 75%) at each spirometry endpoint		From baseline of parent study up to Week 144 (EOT of LTS17510)
Change from LTS17510 study baseline in pre-BD and post-BD forced expiratory flow [FEF] 25% to 75%) at each spirometry endpoint		From baseline of LTS17510 study up to Week 144 (EOT of LTS17510)
Change from parent study baseline in Asthma Control Questionnaire (ACQ)-5, ACQ-6, and ACQ-7 scores	The ACQ is a validated questionnaire that measures the adequacy of asthma control and any changes in asthma control that may occur spontaneously or as a result of treatment. Each item of the ACQ is measured on a 7-point response scale (0=no impairment, 6=maximum impairment). The ACQ score is the mean of the item responses and ranges from 0 (totally controlled) and 6 (severely uncontrolled).	From parent study baseline up to Week 144 (EOT of LTS17510)
Change from LTS17510 study baseline in Asthma Control Questionnaire (ACQ)-5, ACQ-6, and ACQ-7 scores	The ACQ is a validated questionnaire that measures the adequacy of asthma control and any changes in asthma control that may occur spontaneously or as a result of treatment. Each item of the ACQ is measured on a 7-point response scale (0=no impairment, 6=maximum impairment). The ACQ score is the mean of the item responses and ranges from 0 (totally controlled) and 6 (severely uncontrolled).	From LTS17510 study baseline up to Week 144 (EOT of LTS17510)
Change from parent study baseline in Fractional Exhaled Nitric Oxide (FeNO)		From parent study baseline up to Week 144 (EOT of LTS17510)
Change from LTS17510 study baseline in Fractional Exhaled Nitric Oxide (FeNO)		From LTS17510 study baseline up to Week 144 (EOT of LTS17510)
Serum amlitelimab concentrations		From baseline up to Week156 (EOS of LTS17510)
Incidence of anti- amlitelimab antibody positive response		From baseline up to Week 156 (EOS of LTS17510)
Percentage of participants who experienced adverse events.	Data reported for participants who experienced adverse events of special interest (AESI) and serious adverse events (SAEs).	From baseline up to Week 156 (End of Study [EOS] of LTS17510)
Change from parent study baseline and from LTS17510 in Asthma Quality of Life Questionnaire with Standardized Activities (AQLQ [S]) Self-Administered Score	The AQLQ(S) was designed as a self-administered participant reported outcome to measure the functional impairments that are most troublesome to adolescents and adults ≥12 years of age as a result of their asthma over the past two weeks. The instrument is comprised of 32 items, each rated on a 7-point Likert scales from 1 to 7.	From baseline up to Weeks 144 (EOT of LTS17510)
Time to first exacerbation event from LTS17510 study baseline		From baseline of the LTS17510 study Up to Week 144 (EOT of LTS17510)
Annualized rate of severe exacerbation events over treatment period from parent study baseline	Severe exacerbation events over treatment period from parent study baseline are defined as: Worsening of asthma requiring the use of systemic corticosteroids for ≥3 days (or a single IM or IV injection of corticosteroids) or, in the case of a stable maintenance regimen of oral corticosteroids for the treatment of asthma, a doubling of the dose for 3 or more days; or Hospitalization or emergency room visit or urgent care visit because of asthma, requiring systemic corticosteroids.	From baseline of the parent study up to Week 144 (End of Treatment [EOT] of LTS17510)
Annualized rate of severe exacerbation events over treatment period from LTS17510 study baseline	Severe exacerbation events over treatment period from LTS17510 study baseline defined as: Worsening of asthma requiring the use of systemic corticosteroids for ≥3 days (or a single IM or IV injection of corticosteroids) or, in the case of a stable maintenance regimen of oral corticosteroids for the treatment of asthma, a doubling of the dose for 3 or more days; or Hospitalization or emergency room visit or urgent care visit because of asthma, requiring systemic corticosteroids.	From baseline of the LTS17510 study Up to Week 144 (EOT of LTS17510)
Annualized rate of severe asthma exacerbations requiring hospitalization or emergency room or urgent care visit over treatment period from parent study baseline	Severe asthma exacerbations are defined as: Worsening of asthma requiring the use of systemic corticosteroids for ≥3 days (or a single IM or IV injection of corticosteroids) or, in the case of a stable maintenance regimen of oral corticosteroids for the treatment of asthma, a doubling of the dose for 3 or more days; or Hospitalization or emergency room visit or urgent care visit because of asthma, requiring systemic corticosteroids.	From baseline of the parent study up to Week 144 (EOT of LTS17510)
Annualized rate of severe asthma exacerbations requiring hospitalization or emergency room or urgent care visit over treatment period from LTS17510 study baseline	Severe asthma exacerbations are defined as: Worsening of asthma requiring the use of systemic corticosteroids for ≥3 days (or a single IM or IV injection of corticosteroids) or, in the case of a stable maintenance regimen of oral corticosteroids for the treatment of asthma, a doubling of the dose for 3 or more days; or Hospitalization or emergency room visit or urgent care visit because of asthma, requiring systemic corticosteroids.	From baseline of the LTS17510 study up to Week 144 (EOT of LTS17510)

Collaborators and Investigators

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

Publications and helpful links

General Publications

• Seluk L, Davis AE, Rhoads S, Wechsler ME. Novel asthma treatments: Advancing beyond approved novel step-up therapies for asthma. Ann Allergy Asthma Immunol. 2025 Jan;134(1):9-18. doi: 10.1016/j.anai.2024.09.016. Epub 2024 Oct 10.

Helpful Links

• LTS17510 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): September 5, 2023
• Primary Completion (Estimated): September 29, 2026
• Study Completion (Estimated): September 29, 2026

Study Registration Dates

• First Submitted: September 5, 2023
• First Submitted That Met QC Criteria: September 5, 2023
• First Posted (Actual): September 13, 2023

Study Record Updates

• Last Update Posted (Actual): May 20, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Immune System Diseases; Respiratory Tract Diseases; Lung Diseases; Bronchial Diseases; Lung Diseases, Obstructive; Respiratory Hypersensitivity; Hypersensitivity, Immediate; Hypersensitivity; Asthma
• Other Study ID Numbers: LTS17510; U1111-1280-5321 (Registry Identifier: ICTRP); 2023-503385-24 (Registry Identifier: CTIS)

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