Short-term Renal Hemodynamic Effects of Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Short-term Renal Hemodynamic Effects of Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease (ADPKD)

A Phase 2a, Single-center Study Investigating the Short-term Renal Hemodynamic Effects, Safety and Pharmacokinetics/ Pharmacodynamics of Oral Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease at Various Stages of Renal Function

The purpose of the trial was to determine the short-term effects of tolvaptan in patients with autosomal dominant polycystic kidney disease (ADPKD) at various levels of renal function.

Renal function was assessed during screening with the estimated glomerular filtration rate (eGFR), which was calculated with the 4-variable modification of diet in renal disease (MDRD) equation using a minimum of 2 creatinine measurements. The eGFR values were used to categorize participants into 1 of 3 mutually exclusive strata (> 60 [Group A], 30 to 60 [Group B], and < 30 [Group C] mL/min/1.73 m^2). Each of the 3 groups received the same tolvaptan treatment. During the 3-week treatment period, participants were up-titrated on a weekly basis from 45/15 mg to 60/30 mg to 90/30 mg (AM and PM [8 hours later] split-dose) to the maximally tolerated dose. The 3-week treatment period was followed by a 3-week post-treatment period during which no study medication was administered. The effects of the highest tolerated split-dose of tolvaptan on renal hemodynamics and pharmacokinetic and pharmacodynamic parameters were assessed throughout the 6 weeks of the study. The reversibility of changes during the post-treatment period after withdrawal of the drug was determined and the acute transitory effects on kidney volume were also explored.

Participants received tolvaptan for the first 3 weeks of the 6 week study. Participants were up-titrated on a weekly basis from tolvaptan 45/15 mg to 60/30 mg to 90/30 mg oral split-dose (AM and PM [8 hours later]) to the maximally tolerated dose.

Participants received tolvaptan for the first 3 weeks of the 6 week study. Participants were up-titrated on a weekly basis from tolvaptan 45/15 mg to 60/30 mg to 90/30 mg oral split-dose (AM and PM [8 hours later]) to the maximally tolerated dose.

Participants received tolvaptan for the first 3 weeks of the 6 week study. Participants were up-titrated on a weekly basis from tolvaptan 45/15 mg to 60/30 mg to 90/30 mg oral split-dose (AM and PM [8 hours later]) to the maximally tolerated dose.

Mean Change From Baseline in Measured Glomerular Filtration Rate (mGFR) After 3 Weeks of Tolvaptan Treatment and at 3 Weeks Post Treatment.

Renal function measurements were performed using the constant infusion method with 125I-iothalamate and 131I-hippuran. A priming solution containing 20 mL infusion solution (0.04 MBq of 125I-iothalamate and 0.03 MBq of 131I-hippuran) was given at 08:00 hours, followed by a constant infusion of 6 to 12 mL/h, with the lowest infusion rates in subjects with impaired renal function, based on previously known serum creatinine concentrations. Plasma concentrations of both tracers were allowed to stabilize during a 1.5-hour equilibration, which was followed by two 2-hour periods (09:30 to 11:30 hours and 11:30 to 13:30 hours) for simultaneous clearances of 125I-iothalamate and 131I-hippuran. Blood was drawn at 1, 2, 3, 4, and 5 hours post consumption of water/tolvaptan (08:30 hours). The mGFR was corrected for voiding errors.

Mean Change From Baseline in Effective Renal Plasma Flow (ERPF) After 3 Weeks of Tolvaptan Treatment and at 3 Weeks Post Treatment.

Renal function measurements were performed using the constant infusion method with 125I-iothalamate and 131I-hippuran. A priming solution containing 20 mL infusion solution (0.04 MBq of 125I-iothalamate and 0.03 MBq of 131I-hippuran) was given at 08:00 hours, followed by a constant infusion of 6 to 12 mL/h, with the lowest infusion rates in subjects with impaired renal function, based on previously known serum creatinine concentrations. Plasma concentrations of both tracers were allowed to stabilize during a 1.5-hour equilibration, which was followed by two 2-hour periods (09:30 to 11:30 hours and 11:30 to 13:30 hours) for simultaneous clearances of 125I-iothalamate and 131I-hippuran. Blood was drawn at 1, 2, 3, 4, and 5 hours post consumption of water/tolvaptan (08:30 hours).

Mean Change From Baseline in Filtration Fraction (GFR/ERFP) After 3 Weeks of Tolvaptan Treatment and at 3 Weeks Post Treatment.

Renal function measurements were performed using the constant infusion method with 125I-iothalamate and 131I-hippuran. A priming solution containing 20 mL infusion solution (0.04 MBq of 125I-iothalamate and 0.03 MBq of 131I-hippuran) was given at 08:00 hours, followed by a constant infusion of 6 to 12 mL/h, with the lowest infusion rates in subjects with impaired renal function, based on previously known serum creatinine concentrations. Plasma concentrations of both tracers were allowed to stabilize during a 1.5-hour equilibration, which was followed by two 2-hour periods (09:30 to 11:30 hours and 11:30 to 13:30 hours) for simultaneous clearances of 125I-iothalamate and 131I-hippuran. Blood was drawn at 1, 2, 3, 4, and 5 hours post consumption of water/tolvaptan (08:30 hours).

Mean Change From Baseline in Free Water Clearance After 3 Weeks of Tolvaptan Treatment and at 3 Weeks Post Treatment

Renal function measurements were performed using the constant infusion method with 125I-iothalamate and 131I-hippuran. A priming solution containing 20 mL infusion solution (0.04 MBq of 125I-iothalamate and 0.03 MBq of 131I-hippuran) was given at 08:00 hours, followed by a constant infusion of 6 to 12 mL/h, with the lowest infusion rates in subjects with impaired renal function, based on previously known serum creatinine concentrations. Plasma concentrations of both tracers were allowed to stabilize during a 1.5-hour equilibration, which was followed by two 2-hour periods (09:30 to 11:30 hours and 11:30 to 13:30 hours) for simultaneous clearances of 125I-iothalamate and 131I-hippuran. Blood was drawn at 1, 2, 3, 4, and 5 hours post consumption of water/tolvaptan (08:30 hours).

Blood sampling for determination of tolvaptan concentrations took place at the Baseline, Final Treatment, and the Post Treatment or Early Termination visits. At the Final Treatment visit (Day 21 [+/- 1 day)]), blood samples were collected prior to the start of infusion of study treatment and at 1, 2, 3, 4, and 5 hours postdose. At the Baseline (Day 0), and Post Treatment visit (3 weeks [+/-3 days] after last dose), a blood sample was collected prior to the start of infusion of study treatment.

Blood sampling for determination of tolvaptan concentrations took place at the Baseline, Final Treatment, and the Post Treatment or Early Termination visits. At the Final Treatment visit (Day 21 [+/- 1 day)]), blood samples were collected prior to the start of infusion of study treatment and at 1, 2, 3, 4, and 5 hours postdose. At the Baseline (Day 0), and Post Treatment visit (3 weeks [+/-3 days] after last dose), a blood sample was collected prior to the start of infusion of study treatment.

Area Under the Concentration-time Curve From 0 to 5 Hours (AUC0-5) After 3 Weeks of Tolvaptan Treatment.

Blood sampling for determination of tolvaptan concentrations took place at the Baseline, Final Treatment, and the Post Treatment or Early Termination visits. At the Final Treatment visit (Day 21 [+/- 1 day)]), blood samples were collected prior to the start of infusion of study treatment and at 1, 2, 3, 4, and 5 hours postdose. At the Baseline (Day 0), and Post Treatment visit (3 weeks [+/-3 days] after last dose), a blood sample was collected prior to the start of infusion of study treatment.

Percentage Change From Baseline in Total Kidney Volume (TKV) After 3 Weeks of Tolvaptan Treatment and at 3 Weeks Post Treatment.

Mean Change From Baseline in 24 Hour Urine Volume After 3 Weeks Tolvaptan Treatment and at 3 Weeks Post Treatment.

A 24-hour split urine sample (approximate times: 0700 to 1700 hours, 1700 hours to bedtime, and bedtime to 0700 hours) was collected beginning the day before the Baseline, Final Treatment, and Post Treatment visits and ending at admission to the renal function ward. Individual voids in a collection interval were pooled and the total volume determined.

Mean Change From Baseline in 2 Hour Urine Volume After 3 Weeks Tolvaptan Treatment and at 3 Weeks Post Treatment.

The volume of urine from each 2-hour urine collection in the renal function tests at Baseline, Final Treatment, and Post Treatment was recorded. Individual voids in a collection interval were pooled before determination of total volume.

Inclusion Criteria: Diagnosis of autosomal dominant polycystic kidney disease (ADPKD) by Ravine criteria. Exclusion Criteria: Renal replacement therapy. Use of therapies for the purpose of affecting polycystic kidney disease (PKD) cysts. Evidence of significant renal disease, eg, active glomerular nephritides, renal cancer, single kidney. Significant risk-factors for renal impairment, eg, chronic use of diuretics, advanced diabetes, use of nephrotoxic drugs. History of significant coagulation defects or hemorrhagic diathesis.

Boertien WE, Meijer E, de Jong PE, Bakker SJ, Czerwiec FS, Struck J, Oberdhan D, Shoaf SE, Krasa HB, Gansevoort RT. Short-term renal hemodynamic effects of tolvaptan in subjects with autosomal dominant polycystic kidney disease at various stages of chronic kidney disease. Kidney Int. 2013 Dec;84(6):1278-86. doi: 10.1038/ki.2013.285. Epub 2013 Jul 31.

Reddy B, Chapman AB. Acute Response to Tolvaptan in ADPKD: A Window to Predict Long-term Efficacy? Am J Kidney Dis. 2015 Jun;65(6):811-3. doi: 10.1053/j.ajkd.2015.03.004. No abstract available.

Boertien WE, Meijer E, de Jong PE, ter Horst GJ, Renken RJ, van der Jagt EJ, Kappert P, Ouyang J, Engels GE, van Oeveren W, Struck J, Czerwiec FS, Oberdhan D, Krasa HB, Gansevoort RT. Short-term Effects of Tolvaptan in Individuals With Autosomal Dominant Polycystic Kidney Disease at Various Levels of Kidney Function. Am J Kidney Dis. 2015 Jun;65(6):833-41. doi: 10.1053/j.ajkd.2014.11.010. Epub 2015 Jan 15.

Kramers BJ, van Gastel MDA, Boertien WE, Meijer E, Gansevoort RT. Determinants of Urine Volume in ADPKD Patients Using the Vasopressin V2 Receptor Antagonist Tolvaptan. Am J Kidney Dis. 2019 Mar;73(3):354-362. doi: 10.1053/j.ajkd.2018.09.016. Epub 2018 Dec 19.