Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of SAR442501 in Pediatric Participants With Achondroplasia (upreACH-2)

A Phase 2, Open-label, Multi-center, 2-stage Sequential Cohort, Dose Escalation Study to Assess the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of Subcutaneous SAR442501 in Pediatric Participants With Achondroplasia

This is a Phase 2, open-label, multicenter, study to evaluate safety, tolerability and efficacy of SAR442501 in children from birth up to 12 years of age with Achondroplasia.

Study Overview

• Status: Terminated
• Conditions: Osteochondrodysplasia
• Intervention / Treatment: Drug: SAR442501

Detailed Description

Up to approximately 275 weeks: 3 weeks Screening + 52 weeks primary treatment period + up to approximately 216 weeks extended treatment period+ 4 weeks follow-up.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Phase 2

Contacts and Locations

Study Locations

• Australia
  • Victoria
    • Parkville, Victoria, Australia, 3052
      • Investigational Site Number : 0360001
• China
  • Shanghai, China, 200120
    • Investigational Site Number : 1560002
  • Wuhan, China, 430030
    • Investigational Site Number : 1560001
• Italy
  • Lombardy
    • Milan, Lombardy, Italy, 20122
      • Investigational Site Number : 3800002
  • Roma
    • Rome, Roma, Italy, 00168
      • Investigational Site Number : 3800001
• South Korea
  • Seoul-teukbyeolsi
    • Seoul, Seoul-teukbyeolsi, South Korea, 03080
      • Investigational Site Number : 4100001
    • Seoul, Seoul-teukbyeolsi, South Korea, 06351
      • Investigational Site Number : 4100002
• Spain
  • Basque Country
    • Vitoria-Gasteiz, Basque Country, Spain, 01008
      • Investigational Site Number : 7240002
  • Catalunya [Cataluña]
    • Esplugues de Llobregat, Catalunya [Cataluña], Spain, 08950
      • Investigational Site Number : 7240001

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants must have ACH with a confirmed mutation in the FGFR3 gene
• Participants and/or parent(s) or legal representative(s) must be willing and able to perform all the study procedures to the best of their physical ability.
• Parent(s) or legal representative(s) capable of giving signed informed consent and participants capable of giving assent when applicable.

Exclusion Criteria:

• Have hypochondroplasia (or the N540K mutation) or short stature condition other than ACH (eg, trisomy 21, pseudochondroplasia)
• Participants have received any dose of medications or investigational product, including human growth hormone, IGF-1, intended to affect participants' stature or body proportions between the completion of OBS16647 and enrollment (Week 0/Day 1/Visit 2).
• Have a history of growth plate closure.
• Long bone fracture within 3 months of enrollment (Week 0/Day 1/Visit 2)
• Current evidence of corneal or retinal disorder/keratopathy.
• Participants have had a previous surgical intervention involving the foramen magnum (Stage 2 only).
• Hyperphosphatemia.

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: Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort 1	Drug: SAR442501; Solution for injection; Subcutaneous injection
Experimental: Cohort 2	Drug: SAR442501; Solution for injection; Subcutaneous injection
Experimental: Cohort 3	Drug: SAR442501; Solution for injection; Subcutaneous injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stage 1: Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs)	An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. An SAE was defined as any untoward medical occurrence (whether considered to be related to study drug or not) that at any dose: resulted in death; or was life-threatening; or required inpatient hospitalization or prolongation of existing hospitalization; or resulted in persistent or significant disability/incapacity; or was a congenital anomaly/birth defect; or was an important medical event. An AESI was an AE (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and immediate notification by the Investigator to the Sponsor was required. The TEAEs were defined as events that were newly reported or reported to worsen in severity after the start of study drug up to 5 days post last dose of the study drug.	From the first dose of study drug administration (Day 1) up to early termination of the study, approximately 58 weeks (Stage 1: SAR442501 Dose A) and 46 weeks (Stage 1: SAR442501 Dose B)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stage 1: Change From Baseline to Weeks 26 and 52 in Growth Velocity Z-Score	Post-treatment annualized growth velocity (AGV) was calculated from height measurements collected during the study. AGV was calculated as: AGV (centimeter per year)= (Height at Date 2 - Height at Date 1) divided by interval length in days x 365.25, where interval length in days was calculated as (Date 2 - Date 1+1). Z scores were calculated using LMS methods (Box Cox power L, Median M and Variation S), where appropriate: If L≠ 0: Z= [(AGV/M)^L-1]/(LxS); If L= 0: Z= ln(AGV/M)/S. A Z score of 0 represents the mean AGV of the reference achondroplasia (ACH) population. For AGV Z scores in children with ACH: Higher Z scores represent better outcomes, meaning faster linear growth relative to age and sex matched reference populations. Lower Z scores represent worse outcomes, indicating slower growth compared to reference norms. Baseline value was defined as last available pre dose height measurement meeting statistical analysis plan specified time interval definitions.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Annualized Growth Velocity	The AGV was defined as follows: (Height at Date 2 - height at Date 1) divided by interval length in days x 365.25, where the interval length in days was calculated as (Date 2 - Date 1 +1) days. The post-treatment AGV was calculated from height measurements collected during the study. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Height Z-Score	Post-treatment AGV was calculated from height measurements collected during the study. AGV was calculated as: AGV (centimeter per year)= (Height at Date 2 - Height at Date 1) divided by interval length in days x 365.25, where interval length in days was calculated as (Date 2 - Date 1+1). Z scores were calculated using LMS methods (Box Cox power L, Median M and Variation S), where appropriate: If L≠ 0: Z= [(AGV/M)^L-1]/(LxS); If L= 0: Z= ln(AGV/M)/S. A Z score of 0 represents the mean AGV of the reference population (ACH). For AGV Z scores in children with ACH: Higher Z scores represent better outcomes, meaning faster linear growth relative to age and sex matched reference populations. Lower Z scores represent worse outcomes, indicating slower growth compared to reference norms. Baseline value was defined as last available pre dose height measurement meeting statistical analysis plan specified time interval definitions.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Upper to Lower Body Segment Ratio	The upper to lower body segment ratio was calculated by (standing height or total length - lower body segment length) divided by lower body segment length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Upper to Lower Extremity Ratio	The upper to lower extremity ratio was calculated by (upper arm + forearm length) divided by (upper leg + lower leg length). The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Sitting to Standing Height Ratio	The sitting to standing height ratio was calculated by sitting height divided by standing height, or crown to rump length divided by total length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Arm Span to Height Ratio	The arm span to height ratio was calculated by arm span divided by standing height, or arm span divided by total length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Upper Arm to Forearm Length Ratio	The upper arm to forearm length ratio was calculated by upper arm length divided by forearm length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Upper Leg to Lower Leg Ratio	The upper leg to lower leg length ratio was calculated by upper leg length divided by lower leg length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Head Circumference to Height Ratio	The head circumference to height ratio was calculated by head circumference divided by standing height, or head circumference divided by total length. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 2: Change From Baseline to Week 52 in Brainstem, Skull, and Spine Morphometric and Volumetric Parameters	The magnetic resonance imaging was planned to be collected to measure foramen magnum and other brainstem, skull, and spine morphometric parameters in Stage 2 participants. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Week 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Social Score, Emotional Score, and School Functioning Score	The pediatric quality of life (PedsQL) Generic Core Scales assesses pediatric health related quality of life (HRQOL) across functioning domains. Items use a 5-point scale (0=Never to 4=Almost Always). Responses are reverse scored and linearly transformed to a 0-100 scale (0→100, 1→75, 2→50, 3→25, 4→0), where higher scores indicate better quality of life (fewer problems). Domain scores for Social, Emotional, and School Functioning are calculated from the transformed item scores. If more than 50% of items in a domain are missing, the domain score is not computed. If at least 50% are completed, the domain score equals the mean of the non missing transformed item scores. All domain scores range from 0 (almost always) to 100 (never), with higher scores indicate better HRQOL. Baseline was defined as the last available value prior to the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Psychosocial Health Summary Score, Physical Health Summary Score, and Total Score	The PedsQL core scale was a brief, standardized, generic instrument that was used to measure HRQOL in various pediatric conditions. Psychosocial health summary scores were the meaning of item scores in emotional, social, and school functioning scales; and Physical health summary scores were the meaning of item scores in physical scale. Total score was the mean of all the item scores in all scales. Psychosocial and physical health summary scores and total scores each ranged from 0 (almost always) to 100 (never). Higher scores indicate better HRQOL. For participants aged 5 to 7, only parents completed the questionnaire. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Mobility Score	The screening tool for everyday mobility and symptoms (STEMS) was completed by clinicians for participants 5 years of age and older. The STEMS captures mobility, use of mobility aides, and impact of pain and/or fatigue at the end of the day across 3 environments: home, school/work and community. Mobility aides were recorded using numeric 5-point rating scale, score ranged from 1 to 5, where 1= independent on all surfaces including stairs, 2= use of sticks, 3= use of crutches, 4= use of wheeled walking device, and 5= use of wheelchair or mobility scooter. Lower score indicated the better outcome. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Participants Reported Symptoms	The STEMS was completed by clinicians for participants 5 years of age and older. The STEMS captures mobility, use of mobility aides, and impact of pain and/or fatigue at the end of the day across 3 environments: home, school/work and community. Participant reported symptoms were recorded using letters where A= no pain or fatigue, B1= pain only, B2= fatigue and C= pain and fatigue. This was completed for each of the 3 environments resulting in 3 scores, whereby the numeric rating reflects the use of mobility aides and the letter reflects the symptoms. The baseline value was defined as the last available value before the first dose of study drug. Only participants with a Baseline response of "A" were included in the "A to A," "A to B1," and "A to missing" categories at each time point. Similarly, only participants with a Baseline response of "B1" were included in the "B1 to A" and "B1 to missing" categories at each time point.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in General Fatigue, Sleep/Rest Fatigue and Cognitive Fatigue Scores and Total Score	The PedsQL Multidimensional Fatigue Scale measures fatigue across 3 subscales:General Fatigue, Sleep/Rest Fatigue and Cognitive Fatigue. Items are rated on a 5 point scale (0=Never to 4=Almost Always). Responses are reverse scored and linearly transformed to a 0-100 scale (0→100, 1→75, 2→50, 3→25, 4→0), with higher scores indicate less fatigue and better functioning. Subscale scores are calculated as mean of transformed item scores within each subscale. A Total Score was calculated as mean of all transformed items across subscales. If more than 50% of items are missing within a subscale or across total scale, corresponding score is not computed. If at least 50% are completed, scores are calculated as mean of non missing transformed items. All scores range from 0 (no pain) to 100 (severe pain), with higher scores indicate less fatigue. Baseline was defined as last available value prior to first dose of study drug. For participants aged 5-7 years, only parent proxy report was completed.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Current Pain and Worst Pain Rating (PPQ) Score	The PedsQL PPQ assesses current pain and worst pain intensity in the last week using a visual analog scale as well as pain location using a body map. Current and worst pain were scored separately, and scoring was based on the line length to the nearest 0.5 centimeter (5 millimeter). The score ranged from 0 (no pain) to 100 (severe pain), where higher scores indicated greater levels of pain intensity. The PedsQL PPQ was only administered in participants ages 5 years of age and older using both self-report (ages 8 and older) and parent proxy report (ages 5 and older) forms in all countries. For participants aged 5 to 7, only parents completed the questionnaire. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 2: Change From Baseline to Week 52 in Achievement of Gross Motor, Fine Motor, Communication, and Feeding Milestones	For Stage 2 participants, achievement of developmental milestones was planned to be assessed using the ACH developmental recording form. This form allows developmental milestones to be recorded and was not a formalized screening tool or assessment. The form measures the domains of gross motor function, fine motor function, communication and feeding via participant reports to the Investigator. The form depicts the cumulative percentage distributions for children with ACH for each item as well as norms for reference based on the Denver II test, where available. Data collected via this form was planned to be evaluated descriptively to explore the age at which participants in this study achieve developmental milestones. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Week 52
Stage 1: Plasma Concentration of SAR442501	Blood samples are collected to determine plasma concentration of SAR442501.	Pre-dose and 6, 24 and 72 hours post dose on Day 1; Pre-dose and 3, 6, 12, 24 and 72 hours post dose on Day 57
Stage 1: Maximum Observed Plasma Concentration (Cmax) of SAR442501	Blood samples are collected to determine Cmax of SAR442501. The Cmax of SAR442501 was calculated using non-compartmental method.	Pre-dose and 3, 6, 12, 24 and 72 hours post dose on Day 57
Stage 1: Time to Reach the Maximum Concentration (Tmax) of SAR442501	Blood samples are collected to determine tmax of SAR442501. The tmax of SAR442501 was calculated using non-compartmental method.	Pre-dose and 3, 6, 12, 24 and 72 hours post dose on Day 57
Stage 1: Area Under the Concentration Versus Time Curve From Time 0 to 72 Hours After Study Drug Administration (AUC0-tau) of SAR442501	Blood samples are collected to determine AUC0-tau of SAR442501. The AUC0-tau of SAR442501 was calculated using non-compartmental method.	Pre-dose and 3, 6, 12, 24 and 72 hours post dose on Day 57
Stage 1: Minimum Plasma Concentration (Ctrough) of SAR442501	Blood samples are collected to determine Ctrough of SAR442501. The Ctrough of SAR442501 was calculated using non-compartmental method.	Pre-dose on Days 8, 29, 57, 92, 183, 274, 365 and 449
Stage 1: Change From Baseline to Week 26 in Collagen X Biomarker (CXM) Level	Serum samples were collected to assess the change in CXM level with study drug. The CXM was also named PRO-C10 because the biomarker assay used was aimed to target the recognition of the C terminus of the NC1 domain of type X collagen. The baseline value was defined as the last available value before the first dose of study drug. Change from baseline in CXM level has been reported.	Baseline (Day 1) and Week 26
Stage 1: Change From Baseline to Weeks 26 and 52 in Osteocalcin Level	Serum samples were collected to assess the change in osteocalcin level with study drug. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Bone-Specific Alkaline Phosphatase Level	Serum samples were collected to assess the change in bone-specific alkaline phosphatase level with study drug. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Procollagen Type 1 N-Terminal Propeptide (P1NP) Level	Serum samples were collected to assess the change in P1NP level with study drug. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Change From Baseline to Weeks 26 and 52 in Collagen-Type 1 C-Telopeptide (CTX) Level	Serum samples were collected to assess the change in CTX level with study drug. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52
Stage 1: Number of Participants With Anti-drug Antibodies (ADA) to SAR442501	Serum samples were collected to assess the antibodies to SAR442501. Samples were screened and then confirmed for antibodies binding to SAR442501 and the titer of confirmed positive samples were reported. Positive ADA refers to pre-existing ADA at the pre-dose assessment on Day 1.	From the first dose of study drug administration (Day 1) up to early termination of the study, approximately 58 weeks (Stage 1: SAR442501 Dose A) and 46 weeks (Stage 1: SAR442501 Dose B)
Stage 2: Number of Participants With Change From Baseline to Weeks 26 and 52 in Neurological Examination Findings	A complete neurological examination included assessment of mental status, motor function and balance, sensory exam, newborn and infant reflexes, muscle stretch reflexes in the older children and evaluation of the cranial nerves. The baseline value was defined as the last available value before the first dose of study drug.	Baseline (Day 1) and Weeks 26 and 52

Collaborators and Investigators

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

Publications and helpful links

Helpful Links

• DRI16646 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): October 10, 2023
• Primary Completion (Actual): February 12, 2025
• Study Completion (Actual): February 12, 2025

Study Registration Dates

• First Submitted: September 20, 2023
• First Submitted That Met QC Criteria: September 28, 2023
• First Posted (Actual): October 4, 2023

Study Record Updates

• Last Update Posted (Actual): June 25, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Genetic Diseases, Inborn; Bone Diseases, Developmental; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Osteochondrodysplasias
• Other Study ID Numbers: DRI16646; U1111-1280-5374 (Registry Identifier: ICTRP); 2023-503677-37 (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