Obesity and Uric Acid Stones Study

Obesity Clinical Trial

Official title:

Phentermine/tOpiramate to eND Obesity and Uric Acid Stones Trial (POuND OUT)

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04621929
• Other study ID #: IRB202001895-A-N
• Secondary ID: 1R21DK122317-01A
• Status: Recruiting
• Phase: Phase 3
• Start date: March 31, 2021
• Est. completion date: March 31, 2024

Study information

• Verified date: June 2023
• Source: University of Florida
• Contact: John Marks
• Phone: 352-273-5618
• Email: marksjg[@]ufl.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The investigator proposes an 18 month, feasibility pilot study, randomizing obese and diabetic individuals with pure uric acid nephrolithiasis (UAN) or mixed calcium oxalate (CO) UAN to either phentermine/topiramate or a pragmatic control group who will remain on their standard medication regimen (citrate salts, allopurinol, diet, etc.).

Description:

Mounting evidence indicates that obesity, diabetes mellitus, and kidney stones are inter-connected diseases, particularly uric acid nephrolithiasis (UAN) with or without components of calcium oxalate (CO). Obese or overweight diabetics have a six-fold increased risk to develop UAN/COUAN due to the inability to properly add buffer (ammonium) to urine. Of the FDA approved drugs in the weight loss market, the combination medication phentermine/ topiramate is the most effective and has a unique side effect of alkalinizing the urine (making it less acidic). The hypothesize of this project is that treatment of obese, diabetic patients with phentermine/topiramate will reduce the incidence of UAN/COUAN by 1) direct urinary alkalinization and 2) weight loss. Weight loss will indirectly improve urinary buffering ability through improvement in insulin sensitivity and will decrease renal oxidative stress. The investigative team proposes an 18 month, feasibility pilot study, randomizing 30 obese and diabetic individuals with UAN/COUAN to either phentermine/topiramate (n=20) or a pragmatic control group (n=10) who would remain on standard medication regimen (citrate salts, allopurinol, diet, etc).

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 40
• Est. completion date: March 31, 2024
• Est. primary completion date: December 31, 2023
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 75 Years

Eligibility

Inclusion Criteria:

• have recurrent pure uric acid nephrolithiasis (UAN) or mixed calcium oxalate (CO)/UAN. Recurrent stone disease is defined as at least two spontaneous kidney stone passages, two previous kidney stone procedures, or one previous stone passage and one previous procedure. Pure UAN is defined as at least one previous stone analysis demonstrating 100% uric acid mineral content. Mixed COUAN will be defined as at least one previous stone analysis with any mix of uric acid =80% and =20% calcium oxalate. If participant has more than one stone analysis, the most recent will be considered the current stone type.

• have obesity, defined as BMI > 30 kg/m2.

• have type 2 diabetes mellitus or pre-diabetes, defined as previously diagnosed by laboratory testing (hemoglobin A1c, fasting plasma glucose, or oral glucose tolerance test) or as demonstrated by use of anti-hyperglycemic medications or insulin.

• have at least one 24-hour urine study off medications demonstrating urine pH < 5.8 or a study 24-hr urine demonstrating urine pH < 5.8

Exclusion Criteria:

• contraindications to topiramate, including: recurrent major depression, current substantial depressive symptoms, uncontrolled depression by PHQ 9 score >= 10, history of suicidal ideation or behavior with intent to act (versus exclude those with depression); current pregnancy or attempting to conceive; pre-existing chronic kidney disease with eGFR < 60 at time of enrollment; active cancer or active treatment for cancer (chemotherapy, radiation); and non-ambulatory.

• contraindications to phentermine, including: unstable cardiovascular disease defined as decompensated heart failure, unstable angina, atrial fibrillation, uncontrolled blood pressure (>160 systolic), hyperthyroidism; monoamine oxidase inhibitor use; current history of drug or alcohol abuse.

Related Conditions & MeSH terms

• Diabetes Mellitus
• Diabetes Mellitus, Type 2
• Nephrolithiasis
• Obesity
• Pre-Diabetes
• Prediabetic State
• Type 2 Diabetes Mellitus in Obese
• Uric Acid Stones

Intervention

Drug:
• Phentermine / Topiramate Oral Product
All participants in the experimental group will receive oral generic tablet phentermine (18.75 or 37.5 mg dose) and topiramate (daily 100 mg or 150 mg dose)

Combination Product:
• Citrate Salts, Allopurinol, Diet
Control participants will complete initial visit requirements and study enrollment and will be maintained on their current therapy.

Locations

Country	Name	City	State
United States	University of Florida	Gainesville	Florida

Sponsors (2)

Lead Sponsor	Collaborator
University of Florida	National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Kidney stone growth (mm2) as determined by non-contrast CT scan	Existing kidney stone growth	18 months
Primary	New kidney stone formation (mm2) as determined by non-contrast CT scan	Formation of a new kidney stone	18 months
Secondary	Change in weight	Expressed as total percent body weight loss (total weight loss in pounds/starting weight in pounds)	18 months
Secondary	Change in urinary pH parameters	Absolute change in urine pH (end of study compared to baseline)	18 months
Secondary	Change in hemoglobin A1c	Percent change in A1c (end of study compared to baseline)	18 months
Secondary	Change in urinary citrate parameters	Percent change in urinary citrate	18 months
Secondary	Change in urinary calcium parameters	Percent change in urinary calcium	18 months
Secondary	Change in urinary uric acid parameters	Percent change in urinary uric acid	18 months