CaOx Stone Prevention

NCT07225764 | Recruiting Phase 4 FDA Drug

• 1 other identifier: STUDY-25-00784
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

This single-center randomized controlled trial at Mount Sinai West will enroll 80 patients undergoing percutaneous nephrolithotomy for calcium oxalate stones. Participants will be randomized to receive either empiric therapy or selective therapy guided by 24-hour urine evaluation. The primary outcome is change in calcium oxalate supersaturation at 4 weeks, aiming to determine whether empiric therapy can provide outcomes comparable to selective therapy while simplifying access to prevention.

Conditions

Kidney Stones

Keywords

kidney stones; calcium oxalate; nephrolithiasis

Outcome Measures

Primary Outcomes (1)

• Changes in super saturation of calcium oxalate

  Change in urine calcium oxalate supersaturation from baseline to the final follow-up visit, measured via 24-hour urine collection. This is a marker that can be predictive of stone episodes, as recurrent stones may take years to develop.

  4-6 weeks

Secondary Outcomes (3)

• Changes in urinary oxalate levels

  4-6 weeks

• Changes in urinary calcium levels

  4-6 weeks

• Chlorthalidone Adherence Survey (adapted from Brief Medication Questionnaire)

  4-6 weeks

Study Arms (2)

Empiric Therapy

EXPERIMENTAL

Patients randomized to the empiric group will receive treatment based on the pH on urinalysis and stone composition. Patients with greater than 50% calcium oxalate monohydrate (COM) stone composition will be counseled on a low oxalate diet by a medical provider. Patients with greater than 50% calcium oxalate dihydrate (COD) stone composition will be prescribed 25 mg of chlorthalidone once a day. In the rare event the stone composition is 50% COM and 50% COD, then those patients will receive both low oxalate diet counseling and a prescription for chlorthalidone.

Drug: Chlorthalidone; Behavioral: Low oxalate diet

Selective Therapy

ACTIVE COMPARATOR

Patients randomized to the selective group will undergo medical therapy based on the American Urological Association (AUA) guidelines from the 24-hour urine collection results. Patients with idiopathic hyperoxaluria (\> 40mg/day) will receive a low oxalate diet and receive the same dietary counseling, handout, and questionnaire as the empiric group. Patients with idiopathic hypercalciuria (\> 250mg in men, \>200mg in women) will be prescribed 25mg of chlorthalidone once a day.

Drug: Chlorthalidone; Behavioral: Low oxalate diet

Interventions

Chlorthalidone DRUG

Chlorthalidone 25 mg orally once daily is used to reduce urinary calcium excretion and prevent recurrent calcium-containing kidney stones. In this study, it is prescribed either based on stone composition (empiric group) or guided by 24-hour urine results (selective group) for participants meeting criteria for hypercalciuria or calcium oxalate dihydrate stones.

Empiric Therapy; Selective Therapy

Low oxalate diet BEHAVIORAL

Participants receive counseling to follow a low oxalate diet, limiting high oxalate foods (\>50 mg/100 g) and restricting moderate oxalate foods (\<50 mg/100 g) to a single four-ounce serving per day. The diet is prescribed either based on stone composition (empiric group) or guided by 24-hour urine results (selective group) for participants with idiopathic hyperoxaluria or calcium oxalate monohydrate stones.

Empiric Therapy; Selective Therapy

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult age of 18 years
• Diagnosed with kidney stones and scheduled for PCNL.
• Calcium Oxalate Stone Former
• Pre-operative CT-scan within 90 days of surgery and stone density with \> 1000 Hounsfield units
• Non-pregnant or breastfeeding
• Able and willing to provide informed consent.
• Pre-operative eGFR greater than 70 mL/min/1.73 m² -Negative pre-operative urine culture

You may not qualify if:

• Documented history of gastric or intestinal bypass, liver disease, history of gastrointestinal malabsorptive disease (Crohn's disease, ulcerative colitis, and short-gut syndrome)
• Hyperparathyroidism -Renal tubular acidosis
• Active kidney stone prevention treatment (use of thiazides, alkaline therapy, or low oxalate diet) at the time of surgery
• History of hypokalemia or baseline hypotension
• Allergy to medications used in trial or sulfa-containing medications
• Patient prescribed thiazide, loop diuretics, carbonic anhydrase inhibitors, xanthine oxidase inhibitors, active Vitamin D, bisphosphonates, denosumab, glucocorticoids, or potassium supplementation

Sponsors & Collaborators

• Icahn School of Medicine at Mount Sinai: lead

Study Sites (1)

Mount Sinai West

New York, New York, 10019, United States

RECRUITING

MeSH Terms

Conditions

Kidney Calculi; Nephrolithiasis

Interventions

Chlorthalidone

Condition Hierarchy (Ancestors)

Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Urolithiasis; Urinary Calculi; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Benzenesulfonamides; Sulfonamides; Amides; Organic Chemicals; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Benzophenones; Phthalimides; Imides; Ketones; Sulfones; Sulfur Compounds; Isoindoles; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds

Study Officials

• Mantu Gupta, MD

  Mount Sinai West

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Blair Gallante, MPH

CONTACT

631-991-1159; blair.gallante@mountsinai.org

Mantu Gupta, MD

CONTACT

212-241-1272; mantu.gupta@mountsinai.org

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Chair of Urology, MSW and MSM Hospitals Professor, Icahn School of Medicine at Mount Sinai Director of Endourology, Mount Sinai Medical Center

Study Record Dates

• First Submitted: November 5, 2025
• First Posted: November 10, 2025
• Study Start: October 23, 2025
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): June 30, 2027
• Last Updated: November 10, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)