Prospective Clinical Assessment Study in Children With Achondroplasia (ACH)

Open to people ages 30 months to 10 years

• Signed informed consent by study participant or parent(s) or legally authorized representative (LAR) and signed informed assent by the study participant (when applicable)
• Aged 2.5 to 10 years (inclusive) at study entry
• Diagnosis of ACH
• Ambulatory and able to stand without assistance
• Study participants and parent(s) or LAR(s) are willing and able to comply with study visits and study procedures

• Have hypochondroplasia or short stature condition other than ACH (e.g trisomy 21, pseudoachondroplasia, psychosocial short stature)
• In females, having had their menarche
• Height < -2 or > +2 standard deviations for age and sex based on reference tables on growth in children with ACH
• Annualized height growth velocity ≤1.5 cm/year over a period ≥6 months prior to screening
• Have a concurrent disease or condition that in the view of the Investigator and/or Sponsor, may impact growth or where the treatment is known to impact growth.
• Significant abnormality in screening laboratory results.
• Have been treated with growth hormone, insulin-like growth factor 1 (IGF 1), or anabolic steroids in the previous 6 months or long-term treatment (>3 months) at any time
• Have received a C-type natriuretic peptide (CNP) analog or treatment targeting fibroblast growth factor receptor (FGFR) inhibition at any time
• Have had regular long-term treatment (>1 month) with oral corticosteroids (low-dose ongoing inhaled steroid for asthma is acceptable)
• Have used any other investigational product or investigational medical device for the treatment of ACH or short stature
• Have had previous limb-lengthening surgery