Long-term safety profile of tolvaptan in autosomal dominant polycystic kidney disease patients: TEMPO Extension Japan Trial

Public support for patients with intractable diseases in Japan: impact on clinical indicators from nationwide registries in patients with autosomal dominant polycystic kidney disease

BACKGROUND

Clinical practice guidelines recommend antihypertensive and tolvaptan therapies for patients with autosomal dominant polycystic kidney disease (ADPKD) in Japan. However, tolvaptan therapy may pose an economic burden. The Japanese Ministry of Health, Labour and Welfare supports patients with intractable diseases. This study aimed to confirm the impact of the intractable disease system in Japan on the clinical treatment of ADPKD.

METHODS

We analyzed the data of 3768 patients with ADPKD having a medical subsidy certificate from the Japanese Ministry of Health, Labour and Welfare in 2015-2016. The following quality indicators were use: the adherence rate to the 2014 clinical practice guideline for polycystic kidney disease (prescription rates of antihypertensive agents and tolvaptan in this cohort) and the number of Japanese patients with ADPKD nationwide started on renal replacement therapy in 2014 and 2020.

RESULTS

Compared with new applications from 2015 to 2016, the prescription rates of antihypertensives and tolvaptan for the indicated patients at the 2017 renewal application increased by 2.0% (odds ratio = 1.41, p = 0.008) and 47.4% (odds ratio = 10.1, p > 0.001), respectively. These quality indicators improved with antihypertensive treatment, especially in patients with chronic kidney disease stages 1-2 (odds ratio = 1.79, p = 0.013) and in those aged < 50 years (odds ratio = 1.70, p = 0.003). The number of patients with ADPKD who were started on renal replacement therapy in Japan decreased from 999 in 2014 to 884 in 2020 in the nationwide database (odds ratio = 0.83, p < 0.001).

CONCLUSIONS

The Japanese public intractable disease support system contributes to improvement of ADPKD treatment.

Vaptans or voluntary increased hydration to protect the kidney: how do they compare?

The adverse effects of vasopressin (AVP) in diverse forms of chronic kidney disease have been well described. They depend on the antidiuretic action of AVP mediated by V2 receptors (V2R). Tolvaptan, a selective V2R antagonist, is now largely used for the treatment of patients with autosomal dominant polycystic kidney disease. Another way to reduce the adverse effects of AVP is to reduce endogenous AVP secretion by a voluntary increase in fluid intake. These two approaches differ in several ways, including the level of thirst and AVP. With voluntary increased drinking, plasma osmolality will decline and so will AVP secretion. Thus, not only will V2R-mediated effects be reduced, but also those mediated by V1a and V1b receptors (V1aR and V1bR). In contrast, selective V2R antagonism will induce a loss of fluid that will stimulate AVP secretion and thus increase AVP's influence on V1a and V1b receptors. V1aR is expressed in the luminal side of the collecting duct (CD) and in inner medullary interstitial cells, and their activation induces the production of prostaglandins, mostly prostaglandin E2 (PGE2). Intrarenal PGE2 has been shown to reduce sodium and water reabsorption in the CD and increase blood flow in the renal medulla, both effects contributing to increase sodium and water excretion and reduce urine-concentrating activity. Conversely, non-steroidal anti-inflammatory drugs have been shown to induce significant water and sodium retention and potentiate the antidiuretic effects of AVP. Thus, during V2R antagonism, V1aR-mediated actions may be responsible for part of the diuresis observed with this drug. These V1aR-dependent effects do not take place with a voluntary increase in fluid intake. In summary, while both strategies may have beneficial effects, the information reviewed here leads us to assume that pharmacological V2R antagonism, with resulting stimulation of V1aR and increased PGE2 production, may provide greater benefit than voluntary high water intake. The influence of tolvaptan on the PGE2 excretion rate and the possibility to use somewhat lower tolvaptan doses than presently prescribed remain to be evaluated.

Tolvaptan-induced isolated elevation of bilirubin in a patient with Gilbert syndrome

Tolvaptan is the current standard of treatment for autosomal dominant polycystic kidney disease. It operates by acting on V2 receptors and blocks vasopressin interactions, causing a reduction in the rate of renal cyst growth and preserving kidney function. The current known risks of tolvaptan involve a serious liver injury characterized by an elevation in total bilirubin and alanine transaminase and aspartate transaminase levels. In this report, we document a unique liver injury characterized by an elevated bilirubin with normal alanine transaminase and aspartate transaminase levels in a patient who is homozygous for the UGT1A1 consistent with Gilbert syndrome.

The role of tolvaptan in pulmonary hypertension: A retrospective study

Pulmonary hypertension (PH) is a severe form of pulmonary vascular disease that can lead to right heart failure (RHF). Nearly 2-thirds of patients with PH die within 5 years. Studies suggest that a new diuretic medication, called tolvaptan (TLV), can be used to treat PH. However, there is still insufficient evidence to confirm its effectiveness. Therefore, we investigated the role of TLV in patients with PH. This retrospective study included 73 patients with PH hospitalized in Shanghai Pulmonary Hospital between November 2019 and March 2022. All patients received 7.5 to 15.0 mg of TLV for 3 to 21 days starting at admission, in addition to targeted drugs and traditional diuretic therapy. The outcomes included the blood pressure, urine and water intake volumes, electrolyte concentrations, and renal, liver, and cardiac function indexes before and after TLV treatment. In addition, we assessed the clinical symptoms and adverse reactions during the treatment. After TLV treatment, the water intake and urine volumes significantly increased, and body weight, diastolic blood pressure (DBP) and mean arterial pressure significantly decreased. Total bilirubin, direct bilirubin, N-terminal pro-brain natriuretic peptide, and serum uric acid (UA) levels after TLV treatment were significantly lower than before treatment. After TLV treatment, dyspnea significantly improved in 71 of 73 patients, and lower limb edema disappeared in 42 of 53 patients. No obvious adverse reactions occurred during the TLV treatment period. These results suggest that adding TLV to targeted drug and traditional diuretic therapies is effective for patients with PH. However, more data are required to support these findings.

Safety and efficacy of Tolvaptan in real-world patients with autosomal dominant polycystic kidney disease- interim results of SLOW-PKD surveillance

BACKGROUND

Tolvaptan is a vasopressin type 2 receptor antagonist and has been used to treat autosomal dominant polycystic kidney disease (ADPKD) since 2014. There has been limited real-world data on the safety and efficacy of tolvaptan.

METHODS

This post-marketing surveillance was conducted to evaluate the long-term safety and the efficacy of tolvaptan in Japanese patients with ADPKD in real-world clinical settings. The baseline characteristics of 1630 patients treated with tolvaptan are reported. Safety analysis comprises evaluation of adverse drug reactions (ADRs). The efficacy evaluation includes percent change in total kidney volume (TKV) and change in estimated glomerular filtration rate (eGFR) before and after tolvaptan treatment.

RESULTS

Mean age was 49.7 ± 11.2 years and 843 (51.7%) patients were male. Baseline TKV was 2158 ± 1346 mL and eGFR was 44.4 ± 21.7 mL/min/1.73 m². The majority of CKD patients were stage G3b (27.0%) and G4 (30.1%). Frequently reported ADRs were hepatic function abnormal (8.3%), thirst (8.2%), and hyperuricaemia (6.9%). The frequency of ALT elevation (> 30 and > 90 IU/L) was slightly high (32.9 and 8.3%) to previous studies. After tolvaptan treatment, the annual rate of percentage change in TKV reduced from 11.68%/year to 2.73%/year (P < 0.0001). Similar results were also obtained for the effect on change in eGFR from - 3.31 to - 2.28 mL/min/1.73 m²/year after initiation of tolvaptan treatment (P = 0.0403).

CONCLUSION

There were no major problems with safety of tolvaptan treatment and comparable efficacy for TKV and eGFR was observed in relation to the previous pivotal two randomized control trials in this post-marketing surveillance.

Effect of tolvaptan in Japanese patients with autosomal dominant polycystic kidney disease: a post hoc analysis of TEMPO 3:4 and TEMPO Extension Japan

Background

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive condition that eventually leads to end-stage renal disease. A phase 3 trial of tolvaptan (TEMPO 3:4; NCT00428948) and its open-label extension (TEMPO Extension Japan: TEMPO-EXTJ; NCT01280721) were conducted in patients with ADPKD. In this post hoc analysis, effects on renal function and the safety profile of tolvaptan were assessed over a long-term period that included the 3-year TEMPO 3:4 and the approximately 3-year TEMPO-EXTJ trials.

Methods

Patients from Japanese trial sites who completed TEMPO 3:4 were offered participation in TEMPO-EXTJ. Patients whose efficacy parameters were measured at year 2 in TEMPO-EXTJ for efficacy evaluation were included. The annual slope of the estimated glomerular filtration rate (eGFR) and growth in total kidney volume (TKV) were analyzed.

Results

In patients who received tolvaptan in TEMPO 3:4 and TEMPO-EXTJ, the annual slope of eGFR (mL/min/1.73 m²) was − 3.480 in TEMPO 3:4 and − 3.417 in TEMPO-EXTJ, with no apparent effect of an approximately 3.6-month off-treatment interval between the two trials. In patients who received a placebo in TEMPO 3:4 before initiating tolvaptan in TEMPO-EXTJ, the slope of eGFR was significantly less steep from TEMPO 3:4 (− 4.287) to TEMPO-EXTJ (− 3.364), a difference of 0.923 (P = 0.0441).

Conclusion

The TEMPO-EXTJ trial supports a sustained beneficial effect of tolvaptan on eGFR. In patients who received a placebo in TEMPO 3:4, initiation of tolvaptan in TEMPO-EXTJ was associated with a significant slowing of eGFR decline.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02083-y.

Effect of tolvaptan on renal involvement in patients with autosomal dominant polycystic kidney disease according to different gene mutations

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder caused by mutations in the polycystic kidney disease (PKD) gene. Although tolvaptan has benefits for renal involvement, the different effects depending on the gene mutation type are unknown. Thus, we explore the different effects of tolvaptan on the annual changes in total kidney volume (%TKV) and estimated glomerular filtration rate (eGFR) according to the gene mutation type in ADPKD patients.

METHODS

In total, 135 ADPKD patients were screened, and 22 patients taking tolvaptan for at least a year were retrospectively studied at the Kurume University Hospital. We examined the decline in renal function and %TKV by computed tomography and analyzed the gene mutation. Patients were classified into the following four groups according to gene mutation type: PKD1-truncated, PKD1-non-truncated, PKD2, and mutation not found. Patients were treated with tolvaptan, and the effects of tolvaptan were analyzed according to the gene mutation type.

RESULTS

Patients (age: 52.3 ± 11.2 years) were administered tolvaptan at a dose of 45 or 60 mg. No variation was observed in the annual changes in eGFR (%eGFR) (before: - 10.5% ± 13.9%, after: - 14.4% ± 8.1%, P = 0.139), whereas %TKV was significantly improved after the tolvaptan treatment (before: 14.9% ± 8.0%, after: - 5.4% ± 7.6%, P < 0.001). Unlike %eGFR, tolvaptan treatment significantly improved %TKV, regardless of the type of gene mutation.

CONCLUSIONS

A year treatment with tolvaptan significantly improved %TKV in patients with ADPKD, regardless of the gene mutation type.

Impact of Vaptans on Clinical Outcomes in Cirrhosis Patients: A Meta-Analysis of Randomized Controlled Trials

Background: Vaptans have been confirmed to mobilize ascites and improve hyponatremia in cirrhosis patients. However, the effects of vaptans on all-cause mortality, ascites-related complications, and adverse events in cirrhosis patients have not been fully determined.

Objectives: To systematically evaluate the impact of vaptans on the clinical outcomes in patients with cirrhosis.

Materials and Methods: A systematic review and meta-analysis was performed. The PubMed, Embase, and Cochrane’s Library electronic databases were systematically searched for randomized controlled trials (RCTs) investigating the clinical efficacy of vaptans in cirrhosis patients. The results were pooled with a random-effect model.

Results: Eighteen RCTs containing 3,059 cirrhosis patients with ascites and/or hyponatremia were included. Meta-analysis showed that vaptans did not significantly affect the risk of all-cause mortality (RR: 1.02, 95% CI: 0.87 to 1.08, p = 0.83; I² = 2%), consistent with studies with short-term (< 26 weeks) and long-term (≥ 26 weeks) follow-up durations. Additionally, vaptans did not affect the incidence of variceal bleeding (RR: 0.96, p = 0.86), showed a trend of reduced incidence of hepatic encephalopathy (RR: 0.86, p = 0.09), significantly reduced the incidence of spontaneous bacterial peritonitis (RR: 0.75, p = 0.03), but did not significantly affect the risk of hepatorenal syndrome or renal failure (RR: 1.09, p = 0.36). Vaptans did not affect the incidence of adverse events in cirrhosis patients.

Discussion: Treatment with vaptans is not associated with improved survival in cirrhosis patients, although it may reduce the risk of hepatic encephalopathy and spontaneous bacterial peritonitis in these patients. The limitations of the current study include limited number of available studies, small sample sizes of the included studies, variations of baseline patient characteristics, and differences in the dose and duration of vaptans.

Sensory primary cilium is a responsive cAMP microdomain in renal epithelia

Primary cilia are hair-like cellular extensions that sense microenvironmental signals surrounding cells. The role of adenylyl cyclases in ciliary function has been of interest because the product of adenylyl cyclase activity, cAMP, is relevant to cilia-related diseases. In the present study, we show that vasopressin receptor type-2 (V2R) is localized to cilia in kidney epithelial cells. Pharmacologic inhibition of V2R with tolvaptan increases ciliary length and mechanosensory function. Genetic knockdown of V2R, however, does not have any effect on ciliary length, although the effect of tolvaptan on ciliary length is dampened. Our study reveals that tolvaptan may have a cilia-specific effect independent of V2R or verapamil-sensitive calcium channels. Live-imaging of single cilia shows that V2R activation increases cilioplasmic and cytoplasmic cAMP levels, whereas tolvaptan mediates cAMP changes only in a cilia-specific manner. Furthermore, fluid-shear stress decreases cilioplasmic, but not cytoplasmic cAMP levels. Our data indicate that cilioplasmic and cytoplasmic cAMP levels are differentially modulated. We propose that the cilium is a critical sensor acting as a responsive cAMP microcompartment during physiologically relevant stimuli.

Urea treatment in fluid restriction-refractory hyponatraemia

OBJECTIVE

Hyponatraemia in hospitalized patients is common and associated with increased mortality. International guidelines give conflicting advice regarding the role of urea in the treatment of SIADH. We hypothesized that urea is a safe, effective treatment for fluid restriction-refractory hyponatraemia.

DESIGN

Review of urea for the treatment of hyponatraemia in patients admitted to a tertiary hospital during 2016-2017. Primary end-point: proportion of patients achieving a serum sodium ≥130 mmol/L at 72 hours.

PATIENTS

Urea was used on 78 occasions in 69 patients. The median age was 67 (IQR 52-76), 41% were female. Seventy (89.7%) had hyponatraemia due to SIADH-CNS pathology (64.3%) was the most common cause. The duration was acute in 32 (41%), chronic in 35 (44.9%) and unknown in the rest.

RESULTS

The median nadir serum sodium was 122 mmol/L (IQR 118-126). Fluid restriction was first-line treatment in 65.4%. Urea was used first line in 21.8% and second line in 78.2%. Fifty treatment episodes (64.1%) resulted in serum sodium ≥130 mmol/L at 72 hours. In 56 patients who received other prior treatment, the mean sodium change at 72 hours (6.9 ± 4.8 mmol/L) was greater than with the preceding treatments (-1.0 ± 4.7 mmol/L; P < 0.001). Seventeen patients (22.7%) had side effects (principally distaste), none were severe. No patients developed hypernatraemia, overcorrection (>10 mmol/L in 24 hours or >18 mmol/L in 48 hours), or died.

CONCLUSIONS

Urea is safe and effective in fluid restriction-refractory hyponatraemia. We recommend urea with a starting dose of ≥30 g/d, in patients with SIADH and moderate to profound hyponatraemia who are unable to undergo, or have failed fluid restriction.

Updated Canadian Expert Consensus on Assessing Risk of Disease Progression and Pharmacological Management of Autosomal Dominant Polycystic Kidney Disease

PURPOSE

The purpose of this article is to update the previously published consensus recommendations from March 2017 discussing the optimal management of adult patients with autosomal dominant polycystic kidney disease (ADPKD). This document focuses on recent developments in genetic testing, renal imaging, assessment of risk regarding disease progression, and pharmacological treatment options for ADPKD.

SOURCES OF INFORMATION

Published literature was searched in PubMed, the Cochrane Library, and Google Scholar to identify the latest evidence related to the treatment and management of ADPKD.

METHODS

All pertinent articles were reviewed by the authors to determine if a new recommendation was required, or if the previous recommendation needed updating. The consensus recommendations were developed by the authors based on discussion and review of the evidence.

KEY FINDINGS

The genetics of ADPKD are becoming more complex with the identification of new and rarer genetic variants such as GANAB. Magnetic resonance imaging (MRI) and computed tomography (CT) continue to be the main imaging modalities used to evaluate ADPKD. Total kidney volume (TKV) continues to be the most validated and most used measure to assess disease progression. Since the publication of the previous consensus recommendations, the use of the Mayo Clinic Classification for prognostication purposes has been validated in patients with class 1 ADPKD. Recent evidence supports the benefits of a low-osmolar diet and dietary sodium restriction in patients with ADPKD. Evidence from the Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD (REPRISE) trial supports the use of ADH (antidiuretic hormone) receptor antagonism in patients with ADPKD 18 to 55 years of age with eGFR (estimated glomerular filtration rate) of 25 to 65 mL/min/1.73 m2 or 56 to 65 years of age with eGFR of 25 to 44 mL/min/1.73 m2 with historical evidence of a decline in eGFR >2.0 mL/min/1.73 m2/year.

LIMITATIONS

Available literature was limited to English language publications and to publications indexed in PubMed, the Cochrane Library, and Google Scholar.

IMPLICATIONS

Advances in the assessment of the risk of disease progression include the validation of the Mayo Clinic Classification for patients with class 1 ADPKD. Advances in the pharmacological management of ADPKD include the expansion of the use of ADH receptor antagonism in patients 18 to 55 years of age with eGFR of 25 to 65 mL/min/1.73 m2 or 56 to 65 years of age with eGFR of 25 to 44 mL/min/1.73 m2 with historical evidence of a decline in eGFR >2.0 mL/min/1.73 m2/year, as per the results of the REPRISE study.

Effects of tolvaptan on renal function in chronic kidney disease patients with volume overload

Background

Fluid overload in chronic kidney disease (CKD) is generally controlled by diuretics, with potentially harmful effects on renal function. The efficacy of tolvaptan, a vasopressin V2-receptor antagonist and aquaretic, has not been evaluated for fluid control in CKD with reduced renal function.

Methods

Each patient from a group of 24 CKD patients on tolvaptan 15 mg/d plus conventional diuretics (T group) was matched by age and sex with a patient from a group of 24 CKD patients on conventional nonaquaretic diuretics alone not associated to tolvaptan other than tolvaptan (C group). Changes in renal function were compared between the groups for 1 year.

Results

There were no significant differences in blood pressure, hemoglobin levels, cardiac function, urine specific gravity, and urinary sodium concentration between the 2 groups at the beginning of the follow-up period and 1 year after. The estimated glomerular filtration rate (eGFR) by the formula developed by Japanese Society of Nephrology (in mL/min/1.73 m²) decreased: C group (from 28.3±13.6 to 23.0±12.3, p=0.09), T group (from 22.7±12.4 to 19.4±12.2, p=0.18), but both did not reach significance. A 50% reduction in eGFR was observed in 4 patients in the C group and 1 in the T group (p<0.05). A subgroup analysis performed on the patients with stage 3-4 CKD demonstrated a significant reduction in eGFR in the C group (n=17, p=0.04), but not in T group (n=17, p=0.07).

Conclusion

These results suggest that tolvaptan may have less effects on CKD progression among stage 3-4 CKD patients who are on conventional diuretics.