A Study to Assess the Tolerability of Oxylanthanum Carbonate in Patients With Chronic Kidney Disease on Dialysis

The goal of this clinical study is to test the tolerability of oxylanthanum carbonate (OLC) in patients with chronic kidney disease on hemodialysis and have hyperphosphatemia (too much phosphorus in their blood). The main question it aims to answer is whether patients taking OLC for hyperphosphatemia are able to tolerate the drug.

Participants will continue with their scheduled dialysis treatments and replace their current phosphate binder drug with OLC.

This is a 17-week study consisting of 4 parts. In Part 1, patients are screened for eligibility. In Part 2 patients undergo approximately 3-weeks of washout from previous phosphate binder therapy. Part 3 of the study is up to 6-week titration period where patients are treated with OLC starting at a dose level of 1500 mg/day. At the end of 2 weeks, the dose will be adjusted based on serum phosphate level, up to a maximum dose of 3000 mg/day. Part 4 of the study is a 4-week Maintenance Period with patients treated for 4 weeks on the clinically effective dose of oxylanthanum carbonate (OLC) identified in the Titration Period. Patients will return to the clinic for the End-of-Study Visit on the last day of the 4-week Maintenance Period before restarting their prescribed phosphate binder therapy. The primary endpoint will be to evaluate the tolerability of OLC (as assessed by rate of discontinuations due to treatment-related adverse events) and the secondary endpoints are the evaluation of the safety of clinically effective doses of OLC and evaluate the pharmacokinetics of OLC. Once weekly, at one of the patient's scheduled dialysis appointments and at the End-of-Study Visit, the tolerability will be assessed. After the End-of-Study Visit, patients will reinitiate standard therapy. Toxicity will be assessed during the study based on the severity grade (mild, moderate, or severe) as assessed by the Investigator.

Eligibility Criteria:
Inclusion Criteria:

1. Patient must be ≥18 years of age.
2. Patient must be willing and capable of giving written Informed Consent, adhering to dosing and visit schedules, and meeting all study requirements.
3. Patient must be willing and able to swallow whole tablets.
4. Patient has chronic kidney disease and is undergoing, and compliant with, hemodialysis treatment at least 3 times per week for at least 12 weeks prior to signing the ICF, at the Investigator's discretion
5. Patient has mean historical serum phosphorous of ≥4.0 mg/dL and ≤7.0 mg/dL while on a phosphate binder (other than lanthanum carbonate) over the 8 weeks prior to signing the ICF
6. Patient has study specific Screening laboratory serum phosphorus value ≥4.0 mg/dL and ≤7.5 mg/dL during Screening (this value can be repeated up to two times if the value is outside the range).
7. Patient, if on calcimimetic agents or Vitamin D receptor activators (VDRAs), has had no changes in their prescription for at least 4 weeks prior to Day 1 (T1).
8. Patient has a single-pool Kt/V of ≥1.2 during the most recent historical monthly laboratory evaluation.
9. Patient is willing to practice an effective form of contraception from study entry until at least 14 days after the last dose of OLC.
10. Females of childbearing potential must have a negative pregnancy test at Screening.

Exclusion Criteria:

1. Patient with known or suspected intolerance or hypersensitivity to the investigational product or any related lanthanum compound (eg, lanthanum carbonate \[Fosrenol\]).
2. Patient has had prior treatment with lanthanum-based phosphate binder (eg, lanthanum carbonate \[Fosrenol\]) within the past 8 weeks prior to signing the ICF.
3. Patient's most recent historical PTH \>1500 pg/mL within the last 3 months prior to signing the ICF
4. Patient has received any investigational medicinal product (IMP) in a clinical research study within the 30 days prior to Day 1, or less than 5 elimination half-lives prior to Day 1, whichever is longer.
5. Patient is unable to take drugs orally due to disorders or diseases that may affect gastrointestinal function, such as inflammatory bowel diseases (eg, Crohn's disease, ulcerative colitis) or malabsorption syndrome, or procedures that may affect gastrointestinal function, such as gastrectomy, enterectomy, or colectomy as assessed by the Investigator.
6. Patient has a known history of drug or alcohol abuse that the Investigator assesses would interfere with participation in the study.
7. Patient has an active uncontrolled infection on Day 1 in the opinion of the Investigator
8. Patient has an underlying medical condition or other serious illness that would not be appropriate for this study as assessed by the Investigator.
9. Patient is pregnant or breast-feeding.