An Study to Investigate the Safety and Efficacy of PA21 (Velphoro®) and Calcium Acetate (Phoslyra®) in Paediatric and Adolescent Chronic Kidney Disease (CKD) Patients With Hyperphosphataemia

Inclusion Criteria:

1. Subjects 0 to <18 years at time of consent.

2. Subjects with hyperphosphataemia

3. Subjects ≥1 year with CKD Stages 4-5 defined by a glomerular filtration rate <30
mL/min/1.73 m2 or with CKD Stage 5D receiving adequate maintenance haemodialysis (HD)
or peritoneal dialysis (PD) for at least 2 months prior to screening.

4. Subjects <1 year must have CKD.

5. Appropriate written informed consent and, where appropriate/required assent, have been
provided.

Exclusion Criteria:

1. Subjects with hypercalcaemia at screening

2. Subjects with intact parathyroid hormone (iPTH) levels >700 pg/mL at screening.

3. Subjects who are PB naïve who weigh <5 kg at screening. Subjects receiving stable
doses of PBs who weigh <6 kg at screening

4. Subjects requiring feeding tube sizes ≤6 FR (French catheter scale).

5. Subjects with history of major gastrointestinal surgery or significant
gastrointestinal disorders.

6. Subjects with hypocalcaemia (serum total corrected calcium <1.9 mmol/L; <7.6 mg/dL) at
screening.

7. Subject is pregnant (e.g., positive human chorionic gonadotropin test) or breast
feeding.

8. Subject has a significant medical condition(s)