A study to evaluate the pharmacodynamic effects, safety, and tolerability of patiromer in children under 12 years of age with hyperkalaemia.

Inclusion Criteria:

• The following inclusion criteria must be met for each participant:
• - Paediatric participants (<12 years of age) with hyperkalaemia at screening.
• - Participant's age should not reach 12 years during the 28 days of the pharmacodynamic/dose-ranging period.
• - Participant is able to receive regular external feeding and medication, including via tubes, i.e., percutaneous endoscopic gastrostomy (PEG) or entero-gastric feeding tube.
• - At screening/baseline, the results from 2 separate and consecutive potassium assessments using the same measurement method (whole blood, plasma, or serum) need to be above the age-appropriate upper limit of normal (ULN).
• - If taking any renin-angiotensin aldosterone system inhibitors (RAASi), beta blockers, fludrocortisone, or diuretic medications, must be on a stable dose for at least 14 days prior to screening.
• - Parent(s) or legally authorised representative(s) or another appropriate person delegated by the legally authorised representatives must be available to help the study-site personnel ensure follow-up; accompany the participant to the study site on each assessment day; accurately and reliably dispense investigational product as directed.
• - Females of childbearing potential must be non-lactating, must have a negative pregnancy test at screening, and must have used an effective, acceptable form of contraception (e.g., abstinence) for at least 1 month before patiromer administration. Females of childbearing potential must agree to continue using contraception throughout the study and for 1 month after the last dose of patiromer.
• - If undergoing peritoneal dialysis, participants must be on a stable treatment plan for a minimum of 4 weeks prior to screening, or at least 8 weeks prior to screening if newly initiated on peritoneal dialysis.

Exclusion Criteria:

• The following criteria exclude a participant from participating in this trial:
• - Preterm birth infants with <37 weeks of gestation cannot be included in Cohort 3.
• - Participants who due to their general condition, e.g., anaemia or low body weight, are not suitable to have blood volume withdrawn.
• - Any of the following renal conditions: maintenance haemodialysis, renal artery stenosis, and acute kidney injury (defined by 2012 Kidney Disease Improving Global Outcomes) or a history of acute renal insufficiency in the past 3 months. Note: Chronic kidney disease (CKD) is not excluded.
• - A history of or current diagnosis of a severe gastrointestinal (GI) diagnosis or surgery that could affect GI transit of the drug (delayed gastric emptying), such as a severe swallowing disorder, severe gastroesophageal reflux, uncorrected pyloric stenosis, intussusception, any other intestinal obstruction (e.g., Hirschsprung disease, chronic intestinal pseudo-obstruction, clinically significant postsurgical abdominal adhesions) or any gut-shortening surgical procedure prior to screening. Pre-gastric above-mentioned pathologies may be disregarded in case of existence of a PEG or entero-gastric feeding tube, as the PEG or entero-gastric feeding tube will serve for nutrition and investigational product administration.
• - Active cancer, currently on cancer treatment, or history of cancer in the past 2 years (except for non-melanoma skin cancer).
• - Scheduled for kidney transplant procedure during the first 28 days after Day 1.
• - History of sudden infant death in a sibling (only for participants <2 years of age at screening).
• - Use of the following medications if doses have not been stable for at least 14 days prior to screening or if doses are anticipated to change during the 4-week pharmacodynamic/
• dose-ranging period: digoxin, bronchodilators, theophylline, heparins (including low molecular heparins), tacrolimus, mycophenolate mofetil, cyclosporine, trimethoprim, or cotrimoxazole.
• - Use of any investigational product for an unapproved indication within 30 days prior to screening or within 5 half-lives, whichever is longer.
• - Known hypersensitivity to patiromer or its components.
• - If the child is being breastfed:
• a)There is suspicion of current alcohol or substance misuse/abuse in breastfeeding mother
• b)The breastfeeding mother is taking potassium supplements
• Other protocol defined Inclusion/Exclusion criteria may apply

CSL Vifor acknowledges the importance of data transparency and commits to sharing, upon request from qualified scientific researchers, patient-level clinical trial data, study-level clinical trial data, and protocols from clinical trials for medicines and indications approved in the United States (US) and the European Union (EU).

Data from Vifor Pharma sponsored non-interventional and interventional clinical trials (phase 1-4) for medicines and indications approved in the US and the EU, will be shared if the evaluation of the request is positive and two years have elapsed since study completion or termination of the program.

Data is shared upon request from qualified scientific researchers under the prerequisite that the trial subjects' rights are kept fully protected, in particular with regards to Good Clinical Practice and Data Privacy, that the proposed analyses aim to yield an appropriate and valid scientific output and are not in conflict with the publication plan for the study. Requests should be submitted including a description of the data requested, a rationale for the proposed research, a Statistical Analysis Plan, a Publication Plan, qualifications and experience of the research team, disclosure of any conflicts of interests and competitive use of data, and source of research funding. If after evaluation the request is approved, the process of sharing the requested data will be initiated. As a prerequisite, a signed personal data processing and transfer agreement between Vifor Pharma and the data requestor is required.