DS2330b Alone and With Sevelamer in Patients on Chronic Hemodialysis

• DS-2330b PIB (Drug): DS-2330b as powder in bottle with stock solution (PIB)
• Placebo (Drug): Placebo matching stock solution in bottle
• Sevelamer (Drug), also known as Sevelamer carbonate: Sevelamer is a phosphate binder. It is used to decrease serum phosphate (Pi) level in people with chronic kidney disease who are on dialysis.
• DS-2330b Tablet (Drug): DS-2330b as tablet formulation

Primary outcomes

• Part A, Period 1: Maximum concentration (Cmax) of DS-2330a [Period 1, Pre-dose to 48 hours post-dose]
• Part A, Period 2: Cmax of DS-2330a [Period 2, Pre-dose to 48 hours post-dose]
• Part A, Period 1: Time to maximum concentration (Tmax) of DS-2330a [Period 1, Pre-dose to 48 hours post-dose]
• Part A, Period 2: Tmax of DS-2330a [Period 2, Pre-dose to 48 hours post-dose]
• Part A, Period 1: Area under the drug concentration curve (AUC) for DS-2330a over 24 hours (AUC-24) [Period 1, Pre-dose to 24 hours post-dose]
• Part A, Period 2: AUC for DS-2330a for DS-2330a over 24 hours (AUC-24) [Period 2, Pre-dose to 24 hours post-dose]
• Part A, Period 1: AUC at the last observable concentration (AUClast) and to infinity (AUCinf) for DS-2330a [Period 1, Pre-dose to 48 hours post-dose]: Categories (with the same unit of measure ng*hr/mL): AUClast, AUCinf
• Part A, Period 2: AUClast and AUCinf for DS-2330a [Period 2, Pre-dose to 48 hours post-dose]: Categories (with the same unit of measure ng*hr/mL): AUClast, AUCinf
• Parts B and C: Serum phosphate (Pi) levels before hemodialysis [within 15 days]
• All Parts: Number of trial participants with treatment-emergent adverse events (TEAEs) [through trial completion (about 15 months)]: TEAEs are adverse events (side effects) associated with taking an investigational product, whether or not they were caused by the investigational product. Clinically significant changes in physical exam findings, vital signs, electrocardiograms, clinical lab tests and thyroid function are recorded as TEAEs.

Secondary outcomes

• Parts B and C: Cmax of DS-2330a [within 24 hours on Day 1]
• Parts B and C: Cmax of DS-2330a [within 24 hours on Day 13]
• Parts B and C: Tmax of DS-2330a [within 24 hours, Day 1]
• Parts B and C: Tmax of DS-2330a [within 24 hours, Day 13]
• Parts B and C: AUC-24 for DS-2330a [Day 1]
• Parts B and C: AUC-24 for DS-2330a [Day 13]
• Parts B and C: AUCinf for DS-2330a [Day 1]
• Parts B and C: AUCinf for DS-2330a [Day 13]
• Parts B and C: Minimum concentration (Ctrough) of DS-2330a [within 11 days]: Trough blood levels for DS-2330a will be collected before the morning dose (prior to breakfast)
• Part B: Dialysis clearance of DS-2330a [on Day 11]

Sex: All, ages: 18 Years to 80 Years

Inclusion Criteria:

* Has a body mass index (BMI) of 18 kg/m\^2 to 40 kg/m\^2 (inclusive)
* Is on prescribed maintenance hemodialysis (three times a week) for at least 3 months before Screening with adequacy demonstrated by a dialysis clearance within 3 months before the first dose of the investigational medicinal product
* Has permanent vascular access \[arteriovenous (A-V) fistula or graft\]
* Is willing to comply with protocol-specified methods for family planning
* For Parts B and C only:

  1. Has protocol-specified acceptable serum Pi levels at Screening and in serum Pi after up to 3 weeks of washout from all Pi binders
  2. Has protocol-specified acceptable serum Ca\^2+ level and intact parathyroid hormone (iPTH) level at screening

Exclusion Criteria:

* Is employed by the clinic or the sponsor
* Has family relationship with another study participant
* Has any history, current condition, or drug use that per protocol or in the opinion of the investigator might compromise:

  1. safety of the participant or their children
  2. safety of study staff
  3. analysis of study results
* For Parts B and C only:

  1. Is not able to take sevelamer carbonate
  2. Has had partial or total parathyroidectomy within the last six months

• Results publication: Natale P, Green SC, Ruospo M, Craig JC, Vecchio M, Elder GJ, Strippoli GF. Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD). Cochrane Database Syst Rev. 2025 Jun 27;6(6):CD006023. doi: 10.1002/14651858.CD006023.pub4. PMID 40576086

• Global Clinical Leader, Study director, Daiichi Sankyo