Kidney Week

Abstract: SA-PO477

Association Between Initial Dose of Tolvaptan and Reduction of Total Kidney Volume in Autosomal Dominant Polycystic Kidney Disease

Session Information

• ADPKD: Clinical Studies
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidney

• 1001 Genetic Diseases of the Kidney: Cystic

Authors

• Honda, Kenjiro, The University of Tokyo, Tokyo, tokyo, Japan

Kenjiro Honda,

• Matsuura, Ryo, The University of Tokyo Hospital, Tokyo, Japan

Ryo Matsuura,

• Ishimoto, Yu, Tokyo University, Hongo, ToKyo, Japan

Yu Ishimoto,

• Nangaku, Masaomi, the University of Tokyo School of Medicine, Tokyo, Japan

Masaomi Nangaku,

Background

It is occasionally difficult to increase dosage of tolvaptan in autosomal dominant polycystic kidney disease (ADPKD) treatment. The reason of difficulty in increase of tolvaptan dosage is mainly limitation of water intake. Therefore, the effect of lower tolvaptan dose is one of major concerns in ADPKD treatment. Despite that TEMPO3:4 trial and REPRISE trial revealed efficacy of high dose tolvaptan among ADPKD patients, dose-dependent efficacy of tolvaptan remains unclear.

Methods

We selected ADPKD patients who underwent tolvaptan treatment from 2014 to 2017 in our department. The association between averaged dose of tolvaptan during the first six months after the initiation of tolvaptan treatment and change rate of total kidney volume after the treatment. Total kidney volume was estimated by abdominal MRI.

Results

The median age of 10 male and 14 female patients was 50 years (IQR, 45 to 65 years). The total kidney volume, height-adjusted total kidney volume, and annual change rate were 1024mL (918 to 1819mL), 673mL/m (606 to 1137mL/m), +10.7% (+7.7 to +26.6%), respectively. Serum creatinine level was 0.9mg/dL (0.74 to1.42mg/dL), and eGFR was 52mL/min/1.73m² (37.7 to 71.8 mL/min/1.73m²). CKD G2, G3a, G3b and G4 were 11 (44%), 4 (16%), 6 (24%), and 4 (16%) while Mayo classification 1A, 1B, 1C, 1D, and 1E were 0 (0%), 14 (58%), 3 (13%), 4 (17%), and 3 (13%). The annual rate of total kidney volume after tolvaptan treatment for six months was significantly lower than that of pretreatment level by -9.6% (-29.1 to +3.2%) (P＜1x10^-5). When all the patients were divided into two groups according to median of difference between annual total kidney volume change before and six months after tolvaptan treatment, averaged tolvaptan dose during the first six months of tolvaptan treatment was higher in a group with stronger inhibition of kidney enlargement than a group with weaker inhibition of kidney enlargement (P=0.05). Mayo classification and CKD GFR stage were similar between the stronger and weaker inhibition groups.

Conclusion

Early effect on inhibition of total kidney volume growth may be associated with initial tolvaptan dose during the first six months after the initiation of tolvaptan treatment.