Extension Study of Infigratinib in Children with Achondroplasia (ACH)

Key Rollover Subjects Inclusion Criteria:

1. Pediatric subjects with ACH who have completed a previous QED-sponsoredinterventional study with infigratinib.

2. Subjects and parent(s), legal guardian(s), or caregiver(s) are willing and able tocomply with study visits and study procedures.

3. Subjects are able to swallow oral medication.

4. Negative pregnancy test in girls ≥10 years of age or girls of any age who haveexperienced menarche.

5. If sexually active, subject must be willing to use a highly effective method ofcontraception while taking study drug and for 1 month after the last dose of studydrug.

6. The PI, or a person designated by the PI, will obtain written informed consent fromeach subject's parent(s), legal guardian(s), or caregiver(s) and the subject'sassent, when applicable, before any study-specific activity is performed.

Key Rollover Subjects Exclusion Criteria:

1. Subject has concurrent circumstance, disease, or condition that, in the view of thePI and/or sponsor, would interfere with study participation or safety evaluations.

2. Subjects who developed a medical condition that will require the initiation oftreatment with a prohibited medication.

3. Subjects prematurely discontinued a prior QED-sponsored interventional study withinfigratinib

4. Current participation in an ongoing clinical study with a sponsor other than QED

5. Subjects that have reached final height or near final height.

Key Inclusion Criteria for Treatment Naïve Subjects

1. Subject must be 3 to <18 years of age at screening and have growth potential.

2. Subjects and parent(s), legal guardian(s), or caregiver(s) are willing and able tocomply with study visits and study procedures.

3. Subjects are able to swallow oral medication.

4. Subjects who have a diagnosis of ACH, documented clinically and confirmed by genetictesting.

5. Subjects have at least a 6-month period of growth assessment in the PROPEL study (Protocol QBGJ398 001) before study entry.

6. Negative pregnancy test in girls ≥10 years of age or girls of any age who haveexperienced menarche.

7. If sexually active, subject must be willing to use a highly effective method ofcontraception while taking study drug and for 1 month after the last dose of studydrug.

8. The PI, or a person designated by the PI, will obtain written informed consent fromeach subject's parent(s), legal guardian(s), or caregiver(s) and the subject'sassent, when applicable, before any study-specific activity is performed.

Key Exclusion Criteria for Treatment Naïve Subjects

1. Subjects who have hypochondroplasia or short stature condition other than ACH (e.g.,trisomy 21, pseudoachondroplasia, psychosocial short stature).

2. Subjects who have significant concurrent disease or condition that, in the view ofthe PI and/or sponsor, would represent an increased risk to the subject or wouldinterfere with study participation or safety evaluations.

3. Subjects who have a history of malignancy.

4. Subjects who are currently receiving treatment with agents that are known stronginducers or inhibitors of cytochrome P450 (CYP) 3A4.

5. Subjects who discontinued treatment with prohibited medications for at least 5half-lives before screening are eligible.

6. Subjects who have received treatment with growth hormone, insulin-like growth factor 1 (IGF 1), anabolic steroids or any investigational or approved drug for thetreatment of ACH in the previous 6 months.

7. Subjects who have significant abnormality in screening laboratory results.

8. Subjects who have had a fracture within 12 months of screening.