A Phase 4 interventional study of Tenapanor and Placebo in Hyperoxaluria, sponsored by University of Texas Southwestern Medical Center. Completed at 1 site in United States. Open to participants aged 18 Years to 99 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-07.
Sponsored by University of Texas Southwestern Medical Center · Phase 4, Interventional, and Basic science
This pilot study is proposing a novel approach to directly target intestinal oxalate absorption with the drug Tenapanor, which was recently FDA-approved for treating hyperphosphatemia in patients with chronic kidney disease. Tenapanor works by blocking paracellular phosphate absorption by the intestine, but the underlying mechanisms have not been clearly defined. Since phosphate and oxalate ions are absorbed through the same paracellular pathway, and are of similar size and charge, Tenapanor is hypothesized to also reduce dietary oxalate absorption and consequently lower urinary oxalate excretion.
The proposed proof-of-concept studies will determine whether Tenapanor reduces urine oxalate in normal human subjects receiving a high-oxalate diet in a crossover placebo-controlled short-term metabolic study.
Study Design Screening - One 24-hour urine for analysis of stone-risk profile, one blood sample for comprehensive metabolic panel and cystatin C, one stool sample for fecal calprotectin, physical exam, social and medical history, vital signs, demographic information, personal information.This is a two-phase study, each phase is 5 days in duration.
Phase 1: The subjects will consume a pre-prepared oxalate-rich metabolic diet for 5 days while taking 30 mg Tenapanor or Placebo twice a day just prior to the morning and evening meals. On days 4 and 5 they will collect two 24-hour urines for measurement of urine oxalate and stone-risk profile.
Washout: The subjects will undergo a 9-day washout period. Phase 2: The subjects will consume a pre-prepared oxalate-rich metabolic diet for 5 days while taking 30 mg Tenapanor or Placebo twice a day just prior to the morning and evening meals. On days 4 and 5 they will collect two 24-hour urines for measurement of urine oxalate and stone-risk profile.
University of Texas Southwestern Medical Center is the lead sponsor of 990 studies on the registry; 201 are open to participants now.
Of its 135 completed or terminated interventional studies of FDA-regulated products, 100 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
30 mg Tenapanor twice a day
Drug: Tenapanor
30 mg Placebo twice a day
Other: Placebo
Each tablet 30 mg
Also known as: XPHOZAH, IBSRELA
Placebo
Total Urinary Oxalate Excretion Total Urinary Oxalate Excretion
The urinary excretion of oxalate was measured in two 24-hour urine collections on days 4 and 5 of each 5-day study phase. The data from the two 24-hour urine collections were averaged to produce a single reported value.
Time frame: 2 × 24-h urine collections on days 4 and 5 of each 5-day study phase.
Adult participants were recruited from UT Southwestern Medical Center, Dallas, Texas.
| Milestone | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) |
|---|---|---|
| Started | 5 | 5 |
| Completed | 5 | 5 |
| Not completed | 0 | 0 |
The urinary excretion of oxalate was measured in two 24-hour urine collections on days 4 and 5 of each 5-day study phase. The data from the two 24-hour urine collections were averaged to produce a single reported value.
| mg/24-h | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) |
|---|---|---|
| Placebo | 33.2 ± 12.4 | 32.1 ± 5.2 |
| Tenapanor | 48 ± 18.5 | 37.7 ± 14.1 |
Collected over Participants were assessed for adverse events during a site visit at the end of each 5-day study phase.. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Tenapanor | 0/10 (0%) | 0/10 (0%) | 0/10 (0%) |
| Placebo | 0/10 (0%) | 0/10 (0%) | 0/10 (0%) |
Healthy adults with no history of kidney stones or kidney disease.
| Age, Categorical(Participants) | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) | Total |
|---|---|---|---|
| <=18 years | 0 | 0 | 0 |
| Between 18 and 65 years | 5 | 5 | 10 |
| >=65 years | 0 | 0 | 0 |
| Sex: Female, Male(Participants) | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) | Total |
|---|---|---|---|
| Female | 3 | 4 | 7 |
| Male | 2 | 1 | 3 |
| Ethnicity (NIH/OMB)(Participants) | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) | Total |
|---|---|---|---|
| Hispanic or Latino | 1 | 1 | 2 |
| Not Hispanic or Latino | 4 | 4 | 8 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 1 | 1 | 2 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 0 | 0 | 0 |
| White | 4 | 4 | 8 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Region of Enrollment(participants) | Tenapanor (Phase 1), Then Placebo (Phase 2) | Placebo (Phase 1), Then Tenapanor (Phase 2) | Total |
|---|---|---|---|
| United States | 5 | 5 | 10 |
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Plan to share: No
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Hyperoxaluria
University of Texas Southwestern Medical Center