Indapamide and Chlorthalidone to Reduce Urine Supersaturation for Kidney Stone Prevention

NCT ID: NCT06111885

Last Updated: 2025-02-19

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

PHASE2

Total Enrollment

99 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-10-01

Study Completion Date

2027-06-30

Brief Summary

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The aim of this study is to test the efficacy of the two long-acting thiazide-like diuretics indapamide and chlorthalidone in reducing urine supersaturation for calcium oxalate and calcium phosphate compared to the short-acting thiazide diuretic hydrochlorothiazide for the prevention of calcium-containing kidney stones.

Detailed Description

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Background and Rationale:

Kidney stones are the most common condition affecting the kidney. Both prevalence and incidence are increasing rapidly, driven by global warming, urbanization, dietary habits and occupational changes. Kidney stones are highly recurrent, associated with increased mortality, significant morbidity and reduced quality of life, and result in enormous health care expenditures. Hence, effective preventive measures are an undisputed medical need. Thiazide and thiazide-like diuretics ("thiazides") have been the cornerstone of pharmacologic recurrence prevention since \>50 years. The NOSTONE trial (NCT03057431), the only state-of-the-art trial ever performed for pharmacologic recurrence prevention, recently revealed that the most widely prescribed and best studied thiazide, hydrochlorothiazide, is not effectively preventing kidney stone recurrence. If these results also apply to the two more potent and long-acting thiazide-like diuretics indapamide and chlorthalidone is currently unknown. No head-to-head comparison of different thiazides for prevention of kidney stone recurrence has ever been performed. Thus, the role of thiazides in the prevention of kidney stone recurrence remains unclear. This poses the urgent need for a clinical trial that addresses this critical knowledge gap.

Objective:

The investigators plan to conduct a single-center, prospective, randomized, double-blind, crossover trial (INDAPACHLOR) to assess if indapamide and chlorthalidone are superior to hydrochlorothiazide in reducing urine supersaturations of calcium oxalate and calcium phosphate, the two best validated biochemical indicators of kidney stone recurrence risk.

Methodology:

Patients will be allocated to indapamide 2.5 mg once daily, chlorthalidone 25 mg once daily and hydrochlorothiazide 50 mg once daily in a random sequence. The three consecutive active treatment periods of 4 weeks each will be separated by wash-out periods of 4 weeks. The investigators will include 99 adult (\>18 years old) patients with recurrent (≥ 2 stone episodes in the last 10 years) calcium-containing kidney stones (containing ≥ 50% of calcium oxalate, calcium phosphate or a mixture of both). All patients will receive a state-of-the art concomitant non-pharmacologic intervention to prevent stone recurrence according to current guidelines. The primary outcome will be reduction of urine supersaturations of calcium oxalate and calcium phosphate at 4 weeks with indapamide or chlorthalidone compared to hydrochlorothiazide. Secondary outcomes will be changes in 24-hour urine and blood parameters, ambulatory blood pressure and adverse events elicited by indapamide or chlorthalidone compared to hydrochlorothiazide. In an exploratory outcome, the abundance of the thiazide target, the sodium/chloride co-transporter, will be analyzed in urinary extracellular vesicles at 4 weeks.

Expected significance:

INDAPACHLOR will provide long-sought evidence on the comparative efficacy of commonly used thiazides in lowering urine supersaturations and is thus expected to have a strong guideline-changing impact, which will transform patient care for this very common disease.

Conditions

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Kidney Stone

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Eligible individuals will be randomly allocated to one of six treatment sequences with indapamide 2.5 mg, chlorthalidone 25 mg or hydrochlorothiazide 50 mg once daily per os in the morning. Active treatment phases will be 28 days each, separated by wash out periods of 28 days. Active treatment periods can be extended by a maximum of one week, wash out periods can be extended to a maximum of eight weeks.
Primary Study Purpose

PREVENTION

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors
Indapamide, hydrochlorothiazide and chlorthalidone will be provided in identically looking bottles containing identically looking capsules. All trial personnel that is involved in recruitment and care of patients, trial assessment, monitoring and statistical analyses will be blinded to the assigned trial arm.

Study Groups

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Indapamide + Hydrochlorothiazide + Chlorthalidone

1 capsule containing 2.5 mg indapamide per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 50 mg hydrochlorothiazide per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 25 mg chlorthalidone per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Hydrochlorothiazide + Chlorthalidone + Indapamide

1 capsule containing 50 mg hydrochlorothiazide per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 25 mg chlorthalidone per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 2.5 mg indapamide per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Chlorthalidone + Indapamide + Hydrochlorothiazide

1 capsule containing 25 mg chlorthalidone per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 2.5 mg indapamide per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 50 mg hydrochlorothiazide per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Hydrochlorothiazide + Indapamide + Chlorthalidone

1 capsule containing 50 mg hydrochlorothiazide per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 2.5 mg indapamide per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 25 mg chlorthalidone per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Indapamide + Chlorthalidone + Hydrochlorothiazide

1 capsule containing 2.5 mg indapamide per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 25 mg chlorthalidone per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 50 mg hydrochlorothiazide per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Chlorthalidone + Hydrochlorothiazide + Indapamide

1 capsule containing 25 mg chlorthalidone per day for 28 days, followed by a 28 days wash out phase, followed by a second treatment phase with 1 capsule containing 50 mg hydrochlorothiazide per day for 28 days, followed by a 28 days wash out phase, followed by a third treatment phase with 1 capsule containing 2.5 mg indapamide per day for 28 days.

Group Type ACTIVE_COMPARATOR

Indapamide 2.5 MG

Intervention Type DRUG

1 indapamide 2.5 mg capsule per day for 28 days

Hydrochlorothiazide 50Mg

Intervention Type DRUG

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Chlorthalidone 25mg

Intervention Type DRUG

1 chlorthalidone 25 mg capsule per day for 28 days

Interventions

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Indapamide 2.5 MG

1 indapamide 2.5 mg capsule per day for 28 days

Intervention Type DRUG

Hydrochlorothiazide 50Mg

1 hydrochlorothiazide 50 mg capsule per day for 28 days

Intervention Type DRUG

Chlorthalidone 25mg

1 chlorthalidone 25 mg capsule per day for 28 days

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Written, informed consent.
* Age 18 years or older.
* Recurrent kidney stone disease (≥2 kidney stone episodes in the last 10 years prior to randomisation).
* Past kidney stone containing ≥50 % CaOx, CaP, or a mixture of both.

Exclusion Criteria

* Patients with secondary causes of recurrent calcium kidney stones including severe eating disorders (anorexia or bulimia), chronic bowel disease, intestinal or bariatric surgery, sarcoidosis, primary hyperparathyroidism, chronic urinary tract infection.
* Patients with the following medications: Thiazide or loop diuretics, carbonic anhydrase inhibitors (including topiramate), xanthine oxidase inhibitors, alkali, active vitamin D (calcitriol or similar), calcium supplementation, bisphosphonates, denusomab, teriparatide, sodium-glucose co-transporter 2 (SGLT2) inhibitors, strong CYP3A4 inhibitors or inducers (may affect indapamide metabolism), lithium (To be eligible for study participation, patients taking any of the above listed medications at screening must be willing to discontinue these medications at least 28 days before randomization).
* Patients with chronic kidney disease (defined as CKD-EPI eGFR \<30 mL/min).
* Patients with glomerulonephritis.
* Patients with the following biochemical imbalances: severe hypercalcemia (\>2.8 mmol/L), therapy-resistant hypokalemia or conditions with increased potassium loss, severe hyponatremia (\<130 mmol/L), symptomatic hyperuricemia.
* Patients with hepatic encephalopathy or severe liver insufficiency.
* Patients with severe cardiac insufficiency.
* Patient with a recent cerebrovascular event.
* Patients with a solid organ transplant.
* Pregnant and lactating women (A urine pregnancy test must be performed for women of child-bearing potential, defined as women who are not surgically sterilized/hysterectomized, and/or who are postmenopausal for less than 12 months).
* Previous (within 3 months prior to randomization) or concomitant participation in another interventional clinical trial.
* Previous participation in INDAPACHLOR.
* Inability to understand and follow the protocol.
* Allergy to any one of the study drugs.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Department of clinical research, Bern

UNKNOWN

Sponsor Role collaborator

Insel Gruppe AG, University Hospital Bern

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Daniel G Fuster, M.D.

Role: PRINCIPAL_INVESTIGATOR

Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, Bern Switzerland

Locations

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Inselspital, Department of Nephrology and Hypertension

Bern, , Switzerland

Site Status RECRUITING

Countries

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Switzerland

Central Contacts

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Daniel G Fuster, M.D.

Role: CONTACT

+41 (0)31 632 31 44

Facility Contacts

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Daniel Fuster, MD

Role: primary

+41 (0)31 632 31 44

References

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Scoglio M, Bargagli M, Rintelen F, Roumet M, Trelle S, Fuster DG. Indapamide or chlorthalidone to reduce urine supersaturation for secondary prevention of kidney stones: protocol for a randomised, double-blind, cross-over trial (INDAPACHLOR). BMJ Open. 2025 Jun 16;15(6):e101594. doi: 10.1136/bmjopen-2025-101594.

Reference Type DERIVED
PMID: 40523783 (View on PubMed)

Other Identifiers

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INDAPACHLOR Trial

Identifier Type: -

Identifier Source: org_study_id

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