A Study of a Novel Iron-based Phosphate Binder AP301 in Patients With Hyperphosphatemia in the U.S. and China (RESPOND-2)

January 28, 2026 updated by: Alebund Pharmaceuticals

A Randomized, Double-Blind, Multi-Regional, Phase 3 Study to Evaluate the Efficacy and Safety of AP301 on Serum Phosphorus Control in Chronic Kidney Disease Patients Receiving Maintenance Dialysis With Hyperphosphatemia

The goal of this clinical trial is to learn if AP301 could work in the patients receiving maintenance dialysis with elevated blood phosphate. The main questions it aims to answer are:

  • Does AP301 lower blood phosphate levels?
  • Does AP301 works on serum calcium level, calcium times phosphate level, and intact parathyroid hormone level?
  • What discomfort or medical problem do the patients have when taking AP301?
  • Does AP301 improve quality of life in Chinese patients?

The researchers will compare AP301 to an ineffective comparator (a look-alike substance that contains low dose AP301) to see if AP301 works to treat elevated blood phosphate.

In the study, the patients will experience the following stages in a chronicle order:

  • Stop all using blood phosphate-lowering drugs,
  • Take AP301 or the comparator three times a day for 8 weeks,
  • Take AP301 three times a day for 24 weeks, and
  • Take AP301 or the comparator three times a day for 3 weeks.

In the first 32 weeks, the dose of AP301 will be adjusted upwards or downwards based on the patient's blood phosphate level and the study doctor's judgment.

If the participant has a blood phosphate level above or below a certain level, they may receive additional treatment to lower the blood phosphate level.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

264

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100035
        • Recruiting
        • Peking University First Hospital
        • Contact:
      • Beijing, Beijing Municipality, China, 102218
      • Beijing, Beijing Municipality, China, 102218
    • Fujian
      • Xiamen, Fujian, China, 361003
        • Recruiting
        • The First Affiliated Hospital of Xiamen University
        • Contact:
    • Henan
      • Zhengzhou, Henan, China, 450003
        • Recruiting
        • Henan Provincial People's Hospital
        • Contact:
      • Zhengzhou, Henan, China, 450003
        • Recruiting
        • Zhengzhou University-First Affiliated Hospital
        • Contact:
    • Hubei
      • Wuhan, Hubei, China, 430060
        • Recruiting
        • Wuhan University People's Hospital
        • Contact:
      • Wuhan, Hubei, China, 430022
        • Recruiting
        • Huazhong University of Science and Technology-Tongji Medical College - Wuhan Union Hospital
        • Contact:
    • Hunan
      • Changsha, Hunan, China, 410013
        • Recruiting
        • Central South University-The Third Xiangya Hospital
        • Contact:
    • Jiangsu
      • Nanjing, Jiangsu, China, 210009
        • Recruiting
        • Southeast University-Zhongda Hospital
        • Contact:
      • Nanjing, Jiangsu, China, 210029
        • Recruiting
        • Jiangsu Province Hospital (The First Affiliated Hospital with Nanjing Medical University)
        • Contact:
      • Nantong, Jiangsu, China, 226001
        • Recruiting
        • Nantong University-Affiliated Hospital
        • Contact:
      • Wuxi, Jiangsu, China, 214023
        • Recruiting
        • Nanjing Medical University-Wuxi People's Hospital (Wuxi No.1 People's Hospital)
        • Contact:
      • Yangzhou, Jiangsu, China, 225002
    • Jiangxi
      • Nanchang, Jiangxi, China, 330006
        • Recruiting
        • Jiangxi Provincial People's Hospital
        • Contact:
    • Shandong
      • Qingdao, Shandong, China, 266000
        • Recruiting
        • Qingdao University-The Affiliated Hospital
        • Contact:
      • Yantai, Shandong, China, 264099
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China, 200032
      • Shanghai, Shanghai Municipality, China, 200080
        • Not yet recruiting
        • Children's Hospital of Fudan University
        • Contact:
      • Shanghai, Shanghai Municipality, China, 200000
        • Recruiting
        • Shanghai Jiao Tong University School of Medicine (SJTUSM)-Renji Hospital
        • Contact:
      • Shanghai, Shanghai Municipality, China, 200040
      • Shanghai, Shanghai Municipality, China, 200336
    • Sichuan
      • Chengdu, Sichuan, China, 610072
        • Recruiting
        • Sichuan Provincial People'S Hospital
        • Contact:
  • United States
    • California
      • Granada Hills, California, United States, 91344
      • San Dimas, California, United States, 91773
        • Recruiting
        • North America Research Institute - San Dimas
        • Contact:
    • Colorado
      • Lone Tree, Colorado, United States, 80124
    • Connecticut
      • Orange, Connecticut, United States, 06477
        • Recruiting
        • PACT Kidney Care - Orange
        • Contact:
    • Florida
    • Georgia
      • Dalton, Georgia, United States, 30720
        • Recruiting
        • Nephrology & Hypertension Specialists
        • Contact:
    • Louisiana
      • Baton Rouge, Louisiana, United States, 70808
    • Mississippi
      • Columbus, Mississippi, United States, 38801
      • Tupelo, Mississippi, United States, 38801
    • New Mexico
      • Gallup, New Mexico, United States, 87301
        • Recruiting
        • High Desert Nephrology Association - US Renal Care
        • Contact:
    • New York
      • Cheektowaga, New York, United States, 14215
        • Recruiting
        • US Renal Care - West Cheektowaga
        • Contact:
      • Ridgewood, New York, United States, 11385
    • Ohio
      • Toledo, Ohio, United States, 43613
    • Texas
      • Dallas, Texas, United States, 75237
      • Fort Worth, Texas, United States, 76110
      • McAllen, Texas, United States, 78503
        • Recruiting
        • Gamma Medical Research
        • Contact:
      • San Antonio, Texas, United States, 78211
      • San Antonio, Texas, United States, 78251

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Provision of signed and dated ICF
  • Age ≥ 12 years when signing the ICF
  • Patients on dialysis for ≥ 3 months before signing the ICF and throughout the study
  • For HD patients, spKt/V ≥ 1.2; for PD patients, total Kt/V ≥ 1.7/week

  • Patients who receive phosphate-lowering drugs over 4 weeks and their serum phosphate level is:

    1. Screening: 1.13 mmol/L (3.5 mg/dL) ≤ serum phosphate < 2.58 mmol/L (8.0 mg/dL)
    2. After washout: 1.94 mmol/L (6.0 mg/dL) ≤ serum phosphate < 3.23 mmol/L (10.0 mg/dL)

Key Exclusion Criteria:

  • History or plan of kidney transplantation
  • History or plan of parathyroid intervention 6 months before signing the ICF
  • Serum calcium < 1.9 mmol/L (7.6 mg/dL) or > 2.75 mmol/L (11 mg/dL) at screening
  • Serum intact parathyroid hormone > 127 pmol/L (1200 pg/mL) at screening
  • Presence of clinically significant gastrointestinal (GI) disorder
  • History of gastrectomy or duodenectomy, or GI surgery within 3 months before signing the ICF
  • Known allergic to any ingredient of AP301, or known history of severe allergies leading to emergency medical care
  • Female who are breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: AP301
A blood phosphate-lowering medication containing iron
Drug: AP301
Three times a day, administered orally with three meals at a daily dose level from 2.7g to 9.0g
Experimental: AP301 Low Dose
A blood phosphate-lowering medication containing iron, but with a low dose considered as ineffective
Drug: AP301 Low Dose
Three times a day, administered orally with three meals at a daily dose level from 0.075g to 0.25g

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in serum phosphate concentrations in the AP301 and the AP301 low dose groups
Time Frame: From Baseline to the end of Week 8
The amount of phosphate in the blood will be measured with a standard laboratory test. The change in phosphate levels will be compared between the group receiving AP301 and the group receiving AP301 low dose.
From Baseline to the end of Week 8

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Chang in serum phosphate concentrations in the AP301 maintenance dose and the AP301 low dose groups
Time Frame: From the beginning of Week 33 to the end of Week 35
The amount of phosphate in the blood will be measured with a standard laboratory test. The change in phosphate levels will be compared between the group receiving AP301 maintenance dose and the group receiving AP301 low dose.
From the beginning of Week 33 to the end of Week 35
Change in serum phosphate concentrations over time throughout the study
Time Frame: From Baseline to the end of Week 35
From Baseline to the end of Week 35
Change in serum calcium (Ca) and intact parathyroid hormone levels over time
Time Frame: From Baseline to the end of Week 35
The amount of calcium and intact parathyroid hormone (iPTH) in the blood will be measured with standard laboratory tests.
From Baseline to the end of Week 35
Number of adverse events
Time Frame: From Baseline to Follow-up (Up to 37 weeks)
From Baseline to Follow-up (Up to 37 weeks)
Change in QT intervals measured by 12-lead electrocardiagram test over time
Time Frame: From Baseline to the end of Week 35
The duration of QT intervals will be measured with a standard 12-lead electrocardiagram test.
From Baseline to the end of Week 35

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in the health-related quality of life questionnaires of EQ-5D-5L in Chinese patients only
Time Frame: From Baseline to Week 33
The change in the scores of the questionnaire EuroQol 5-Dimension 5-Level (EQ-5D-5L), including the health state index score (the higher, the better quality of life) and the visual anaglog scale (ranging from 0 to 100; the higher, the better quality of life).
From Baseline to Week 33
Change in the health-related quality of life questionnaires of KDQoL-36 in Chinese only
Time Frame: From Baseline to Week 33
The change in the scores of the questionnaire Kidney Disease Quality of Life 36-item short form (KDQoL-36). The score ranges from 0 to 100 for five domains, with higher scores indicating better quality of life.
From Baseline to Week 33

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Alebund Pharmaceuticals

Collaborators

Fortrea

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 13, 2025

Primary Completion (Estimated)

June 20, 2026

Study Completion (Estimated)

January 10, 2027

Study Registration Dates

First Submitted

March 19, 2025

First Submitted That Met QC Criteria

April 10, 2025

First Posted (Actual)

April 18, 2025

Study Record Updates

Last Update Posted (Actual)

January 29, 2026

Last Update Submitted That Met QC Criteria

January 28, 2026

Last Verified

June 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AP301-HP-03

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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