Selective Vasopressin V2 Receptor Antagonist Research Articles

#1891 Evaluating the safety and effectiveness of Tolvaptan for management of adult Korean ADPKD patients (ESSENTIAL study): final report

Abstract Background and Aims Tolvaptan, a selective vasopressin V2 receptor antagonist, was first approved by Korean FDA in 2015 as a treatment option in autosomal dominant polycystic kidney disease (ADPKD). In order to prescribe Tolvaptan safely and effectively, we designed the phase 4 clinical trial among Korean ADPKD patients with chronic kidney disease (CKD) stage 1-3. Method Korean patients aged 19 to 50 with rapidly progressing ADPKD were enrolled in the study. The dose titration was performed every one week for a total of 4 weeks. The patient was prescribed Tolvaptan with the maximum tolerable dose up to 120 mg per day. A total duration of Tolvaptan prescription was 24 months. The primary outcome was the incidence of treatment emergent adverse events (TEAE) including drug-induced liver injury (DILI). The secondary outcomes were the annual mean percent change of total kidney volume (TKV) and the annual mean change of estimated glomerular filtration rate (eGFR). Results A total of 117 patients were included in the analysis. Mean age was 38.7 ± 8.4 years old and male were predominant (58.1%). The average TKV was 2066 ± 1094 mL and mean eGFR was 79.7 ± 27.7 mL/min/1.73 m2. Mean duration of Tolvaptan exposure was 1.7 ± 0.6 years and the average daily dose of Tolvaptan was 94.4 ± 24.1 mg/day. A total of 489 treatment-emergent adverse events (TEAE) occurred in 106 (90.6%) patients during study duration. The drug-induced liver injury and aquaresis-related adverse events were two most common adverse events. A total of 17 DILI cases (14.5%) occurred during the study period and mostly within 18-month period. However, liver enzymes were normalized after drug discontinuation The patients with previous history of liver disease as well as those who were prescribed higher dose of Tolvaptan demonstrated higher frequency of DILI. Mean growth rate of TKV after Tolvaptan treatment was 4.5 ± 0.5% and mean eGFR decline rate was -3.0 ± 0.39 mL/min/1.73 m2/year. Comparing with the predicted value from calculation, Tolvaptan attenuated both TKV growth and eGFR decline rate. Conclusion This study is the first post-marketing survey assessing the safety and efficacy of Tolvaptan in Korean ADPKD patients. The incidence of DILI was higher than the previous studies and especially in those with liver disease and higher Tolvaptan prescription dose. While Tolvaptan can effectively reduce TKV and attenuate eGFR decline, the clinicians should be aware of higher frequency of DILI among Korean population.

Additional renoprotective effect of the SGLT2 inhibitor dapagliflozin in a patient with ADPKD receiving tolvaptan treatment.

Autosomal dominant polycystic kidney disease (ADPKD) is a major cause of end-stage kidney disease (ESKD). Vasopressin plays a pivotal role in ADPKD progression; therefore, the selective vasopressin V2 receptor antagonist tolvaptan is used as a key drug in the management of ADPKD. On the other hand, sodium-glucose cotransporter-2 inhibitors (SGLT2i), which may possibly stimulate vasopressin secretion due to the diuretic effect of the drug, have been shown to have both renal and cardioprotective effects in various populations, including those with non-diabetic chronic kidney disease. However, the effect of SGLT2i in patients with ADPKD have not been fully elucidated. Herein, we report the case of a patient with ADPKD on tolvaptan who was administered the SGLT2i dapagliflozin. The patient was a Japanese woman diagnosed with ADPKD at age 30. Despite the treatment with tolvaptan, eGFR was gradually declined from 79.8 to 50ml/min/1.73m2 in almost 5years and 10mg of dapagliflozin was initiated in the hope of renoprotective effects. Although a small increase in vasopressin levels was observed, eGFR decline rate was moderated after dapagliflozin initiation. This case suggested an additional renoprotective effect of dapagliflozin in patient with ADPKD receiving tolvaptan. Although there is no evidence about the renal protective effect of SGLT2i in patients with ADPKD, we hereby report a case successfully treated with dapagliflozin for approximately 2 years. Further research, including clinical trials, is needed to evaluate whether SGLT2i are effective in patients with ADPKD.

Pharmacokinetics, pharmacodynamics and safety of 15mg-tolvaptan administered orally for 7 consecutive days to Chinese patients with child-Pugh B cirrhosis.

Background: Tolvaptan, a selective vasopressin V2-receptor antagonist, can elicit a diuretic effect without significant electrolyte loss. The aims were to evaluate multiple-dose pharmacokinetics, pharmacodynamics and safety of daily administration of 15mg tolvaptan in Chinese adult patients with confirmed Child-Pugh Class B cirrhosis accompanied by ascites. Methods: This was an open-label, single-center, single- and multiple-dose study. All patients received a daily 15mg dose of tolvaptan for 7 consecutive days. The plasma concentrations of tolvaptan and its two metabolites (DM-4103, DM-4107) were measured using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). In addition, various pharmacokinetics parameters were calculated. The pharmacodynamic outcomes evaluated changes in serum sodium and potassium concentrations, daily urine volume, daily water consumption, fluid balance and body weight. Safety profiles, including the incidence of treatment-emergent adverse events (TEAEs), were carefully recorded. Results: Eleven patients with Child-Pugh B cirrhosis were eventually enrolled in the study. Plasma concentrations of tolvaptan and DM-4107 reached steady-states after 7 days of consecutive oral administration. No accumulation of tolvaptan or DM-4107 was found, but DM-4103 accumulated 18.2-fold after multiple-dosing. The daily urine volume and daily water consumption were statistically significantly increased after administration of tolvaptan from Day 1 to Day 7 (all p < 0.05), accompanied by an increased serum sodium concentration. Of 11 patients, 9 (81.8%) reported 20 TEAEs, with the majority being mild to moderate in severity. The most commonly occurring TEAEs were thirst (45.5%), pollakiuria (36.4%) and dry mouth (27.3%). Conclusion: Tolvaptan at a daily dose of 15mg had a diuretic effect but did not increase serum sodium excretion or lead to tolvaptan accumulation. It is therefore can be safely used for short-term treatment of Chinese adult patients with confirmed Child-Pugh B cirrhosis. Clinical Trial Registration: https://clinicaltrials.gov/search?term=NCT01359462, identifier NCT01359462.

The Efficacy, the Treatment Response and the Aquaretic Effects of a Three-Year Tolvaptan Regimen in Polycystic Kidney Disease Patients.

Tolvaptan, a selective vasopressin V2 receptor antagonist, is the first and only approved specific treatment for Autosomal-Dominant Polycystic Kidney Disease (ADPKD), and is used in current clinical practice. Real clinical data are missing. In this retrospective study, 41 ADPKD patients received tolvaptan for 3 years, from 2018 to 2021. Total kidney volume (TKV) was measured using Magnetic Resonance Imaging, at initiation and at the end of the treatment period. A complete biochemistry/hematology profile and a 24 h urine volume collection were performed monthly for the first 18 months and every 3 months thereafter. At the end of the treatment period, the median (IQR) estimated Glomerular Filtration Rate (e-GFR) was 5.3 (-1.3, 8.7) mL/min higher than the expected e-GFR decline without treatment, while the prediction for End Stage Chronic Kidney Disease (ESKD) had been prolonged by 1 (0, 2) year. Total Kidney Volume did not change significantly (2250 (1357) mL at 3 years of treatment vs. 2180 (1091) mL expected without treatment, p = 0.48). Younger patients with a relatively preserved e-GFR, lower hypertension burden, better familiar renal prognosis and more severe imaging data showed better outcomes. The aquaretic adverse effects of tolvaptan did not affect renal function and electrolyte balance in 51 patients, in a follow-up period of 18 months. Consequently, tolvaptan seems to be effective in preventing progression of ADPKD when administered in a timely manner in patients with better familiar renal history, shorter hypertension duration and worse imaging profile. Increased diuresis does not affect treatment efficacy.

Long-term low-dose tolvaptan efficacy and safety in SIADH

PurposeTolvaptan, a selective vasopressin V2-receptor antagonist, is approved for the treatment of SIADH-related hyponatremia, but its use is limited. The starting dose is usually 15 mg/day, but recent clinical experience suggests a lower starting dose (<15 mg/day) to reduce the risk of sodium overcorrection. However, long-term low-dose efficacy and safety has not been explored, so far. Aim of our study is to characterize safety and efficacy of long-term SIADH treatment with low-dose Tolvaptan.MethodsWe retrospectively evaluated 11 patients receiving low-dose Tolvaptan (<15 mg/day) for chronic SIADH due to neurological, idiopathic and neoplastic causes. Plasma sodium levels were measured before and 1, 3, 5, 15 and 30 days after starting Tolvaptan and then at 3-month intervals. Anamnestic and clinical data were collected.ResultsMean time spanned 27.3 ± 29.8 months (range 6 months-7 years). Mean plasma sodium levels were within normal range 1, 3 and 6 months after starting Tolvaptan as well as after 1, 2, 3, 5 and 7 years of therapy. Neither osmotic demyelination syndrome nor overcorrection were observed. Plasma sodium levels normalization was associated with beneficial clinical effects. Neurological patients obtained seizures disappearance, improvement in neurological picture and good recovery from rehabilitation. Neoplastic patients were able to start chemotherapy and improved their general condition. Patients did not show hypernatremia during long-term follow-up and reported mild thirst and pollakiuria.ConclusionsThe present study shows that long-term low-dose Tolvaptan is safe and effective in SIADH treatment. No cases of overcorrection were documented and mild side effects were reported.

PS-BPB05-6: TOLVAPTAN INDUCES BODY FLUID LOSS AND ACTIVATION OF RENAL UREA-DRIVEN WATER CONSERVATION IN NORMAL RATS

Objective: We recently reported that body fluid loss models such as high salt-induced natriuresis, impaired urine concentration ability via kidney injury, and enhanced transepidermal water loss due to skin barrier dysfunction exhibit initial water loss and subsequent activation of the water conservation system in multiple organs. This activation of the water conservation system restores or even increases water content at the tissue level, which may be involved in abnormal body fluid distribution in various disease models. The water conservation system consists of renal urea recycling, the energy-intensive nature of hepato-muscular ureagenesis, and suppression of cardiovascular energy expenditure to save energy for ureagenesis. However, it is not clarified whether pharmacological fluid loss by diuretics activates the water conservation system. In this study, we examined the effects of water diuresis by tolvaptan, a selective vasopressin V2 receptor antagonist, on the water conservation system in normal rats. Design and method: 10-week-old male Sprague Dawley rats were fed with a control diet or a diet containing 0.1% tolvaptan. We measured water intake and urine volume for two weeks and also evaluated time-dependent changes in renal urea recycling and hepato-muscular ureagenesis in these rats. In addition, we also evaluated the effects of tolvaptan on blood pressure, heart rate, and renal sympathetic nerve activity by a radiotelemetry system in separate animals. Results: Tolvaptan markedly increased urine volume up to 126.7 ± 25.9 ml on day-1, which gradually decreased as much as one-third (48.1 ± 18.0 ml) on day-7. Tolvaptan significantly decreased body water content and increased plasma albumin concentration, an indicator of oncotic pressure, on day-1, suggesting that tolvaptan decreased body fluid and plasma volume on day-1. These changes in total body water content and plasma albumin concentration were restored on day-7. The restoration of body fluid on day-7 was associated with an increase in urea transporter A1-associated renal urea recycling. On the other hand, tolvaptan did not alter hepato-muscular ureagenesis or cardiovascular energy expenditure throughout the treatment. Conclusions: Tolvaptan induces initial body fluid loss by water diuresis and subsequent activation of renal urea recycling to restore the water loss. Activation of the water conservation system in addition to a rise in urine volume may be involved in the unknown distinct effect of the diuretics.

Transcriptomic and metabolic profiling of Tolvaptan treated Autosomal dominant polycystic kidney disease (ADPKD) patient

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is the most common and life‐threatening genetic kidney disease that characterized by the aberrant renal tubule epithelial cells proliferation leads to the formation of multiple fluid‐filled cysts, and most of the ADPKD patient will leads to kidney failure by age of 50. Currently, dialysis or a transplant are the only treatments for end‐stage ADPKD patients. Tolvaptan is a is a selective vasopressin V2‐receptor antagonist which was used to treat hyponatremia in heart failure but was approved by FDA for ADPKD treatment in 2018. However, there are limitations for ADPKD patients to receive Tolvaptan treatment and significant side effects severely affect patient’s life quality. In our study, a 34‐year‐old man was diagnosed with familial ADPKD. He had cysts in kidney (Mayo class 1c) and liver and showed no symptoms other than hypertension. His baseline eGFR was 76.98 ml/min/1.732mg/dL but declined to 57.02 ml/min/1.732mg/dL two years after his first diagnosis, and there was an increase in number and size of the cysts due to the rapidly progressive ADPKD. Tolvaptan was started with the 45‐0‐15 dose and the patient was well‐tolerated. After 60 days of treatment, the renal function dramatic improved (73.02 ml/min/1.732mg/dL). With the titrate to 60‐0‐30 dose of tolvaptan, his eGFR maintains above than 60 ml/min/1.732mg/dL more than 3 months until present.MethodInformation of transcriptome and metabolome has significantly contributed to identifying potential therapeutic targets for the management of diseases. In our study, we collect his blood and urine before Tolvaptan treatment and 2 and 3 months after Tolvaptan treatment for transcriptomic and metabolic profiling. Total RNA was extracted using Trizol® Reagent (Invitrogen, USA) according to the manual. cDNA libraries were prepared by SureSelect XT HS2 mRNA Library Preparation kit (Agilent, USA) and sequenced on Nextseq. Differential expression analysis was performed using StringTie and DEseq2 with genome bias detection/correction using Welgene Biotech's in‐house pipeline. Genes with p value &lt; 0.05 and &gt; 2.0‐fold changes were considered significantly differentially expressed, and functional enrichment assay in differentially expressed genes of each experiment design was performed using clusterProfiler v3.6.ResultsOur data indicates that tight junction proteins (Log2 ratio: CRB3, 11.01; CLDN10, 10.09; MAPK10, 7.34), cytoskeleton regulating proteins (Log2 ratio: FGF17, 9.47; MYH14, 7.04) which also genes involved in the regulation of calcium and MAPK signaling and following focal adhesion proteins were significantly (p&lt;0.05) preserved after 3 months Tolvaptan treatment. Furthermore, Hypoxanthine, Creatine, L‐a‐aminobutyric acid and Trimethylamine N‐oxide were significantly decreased in our metabolomics data analysis which is also indicates the inhibition of paracellular transportation in kidney epithelial/endothelial cells.ConclusionOur data indicates a potential molecular mechanism of Tolvaptan treatment in regulating the integrity of tight junction and kidney cells, and provides novel therapeutic targets in in ADPKD.

Tolvaptan induces body fluid loss and subsequent water conservation in normal rats

We have recently reported that the urea osmolyte-associated water conservation system is activated in fluid loss models such as high salt-induced natriuresis, renal injury-induced impaired renal concentrating ability, or skin barrier dysfunction-induced transepidermal water loss. The system consists of the interaction of multiple organs including renal urea recycling, hepato-muscular ureagenesis, and suppression of cardiovascular energy expenditure. Here, we determined the effect of pharmacological fluid loss induced by tolvaptan, a selective vasopressin V2 receptor antagonist, on water conservation. We evaluated the water conservation system in rats that consumed a control diet or a diet containing 0.1% tolvaptan. Tolvaptan increased urine volume on day 1, but this renal water loss then gradually decreased. Body water and osmolyte content were decreased by tolvaptan on day 1 but had normalized by day 7. Tolvaptan induced fluid loss on day 1, and the following restoration of body fluid on day 7 was associated with an increase in urea transporter A1-associated renal urea recycling. Tolvaptan did not affect hepato-muscular ureagenesis on day 1 and day 7, or cardiovascular energy expenditure during treatment. Thus, tolvaptan-induced fluid loss leads to activation of the water conservation system via renal urea recycling.

Tolvaptan, a vasopressin V2 receptor antagonist, is the world's first approved drug for treatment of autosomal dominant polycystic kidney disease (ADPKD)

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disease. Fluid-filled cysts develop and enlarge in both kidneys, eventually leading to kidney failure. Tolvaptan is a selective vasopressin V2 receptor antagonist and the first and only drug approved for treatment of ADPKD. It blocks binding of arginine vasopressin (AVP) to V2 receptors in the collecting duct of kidney, thereby inducing water diuresis (aquaresis) without losing electrolytes. Therefore, tolvaptan was originally developed and approved as the first oral aquaretic agent for treatment of hyponatremia and fluid volume overload in heart failure and cirrhosis. During the development of tolvaptan as aquaretics, efficacy of V2 antagonist in polycystic kidney animal model was reported and then the development of tolvaptan for ADPKD was also initiated. Cyclic adenosine monophosphate (cAMP) plays an important role in cyst growth by promoting cell proliferation and fluid secretion. Tolvaptan showed suppression of cyst growth through inhibiting AVP-induced cAMP production and delayed the onset of end-stage renal disease in an animal model. In the phase 3 clinical trial in ADPKD patients (TEMPO 3:4 trial), 3-year treatment with tolvaptan slowed the disease progression including increase of kidney volume and decline in renal function. Efficacy of tolvaptan in patients with late-stage ADPKD was confirmed in another 1-year phase 3 REPRISE trial. Tolvaptan is approved for treatment of ADPKD in more than 40 countries and we expect it can contribute to more ADPKD patients worldwide. We also expect that drugs with new mechanisms will be available in the near future.

Effect of oral tolvaptan for 1 year in patients with functional mitral regurgitation.

The effect of the oral selective vasopressin V2-receptor antagonist tolvaptan for chronic phase therapy on patients with FMR remains unclear. We aimed to determine the efficacy of oral tolvaptan in patients with significant functional mitral regurgitation (FMR) to reduce the mortality and rehospitalization due to worsening heart failure (HF). We enrolled 219 patients (mean age 76 ± 9years, 59.4% men) who were admitted at our hospital due to congestive HF during different two 1-year periods. The patients were divided into 2 groups: those who had significant FMR (MR ≥ grade 2 [n = 76]) and those who did not (MR < grade 2 [n = 143]) at discharge. The patients were further divided into a study group that received tolvaptan during follow-up and a control group that did not receive tolvaptan. We used an inverse probability of treatment weighting method with the primary end point defined as overall all-cause mortality and rehospitalization due to worsening HF within 1year. Of the 76 patients with significant FMR at discharge, 2 of 20 (10%) who were administered tolvaptan died and 8 (40%) were readmitted to a hospital. Of the 56 patients who did not receive tolvaptan, 2 (3.5%) died and 18 (27.5%) required rehospitalization. After multiple adjustments, there were no significant differences for overall survival and rehospitalization between the groups (log-rank p = 0.700 and 0.510, respectively). Our results suggest that oral tolvaptan administration in addition to conventional diuretics had less impact on outcomes in patients with significant FMR.

Protective effect of tolvaptan against cyclophosphamide-induced nephrotoxicity in rat models.

Cyclophosphamide (CP) is a chemotherapeutic agent which is extensively used in the treatment of multiple neoplastic and nonneoplastic diseases like breast cancer, lymphomas, systemic lupus erythematosus, and multiple sclerosis. Dose‐limiting side effects, mainly nephrotoxicity is a major problem hindering its use in the clinical practice. CP induces nephrogenic syndrome of inappropriate antidiuresis mostly via the activation of arginine vasopressin V2 receptors. Moreover, CP produces reactive metabolites which is responsible for augmentation of lipid peroxidation and oxidative stress. Tolvaptan (TOL) is a selective vasopressin V2 receptor antagonist used in the treatment of clinically significant hyponatremia, volume overload in heart failure, and liver cirrhosis with edema. The present study aimed to investigate the potential protective effect of TOL in CP‐induced nephrotoxicity. Twenty‐four adult male albino rats were randomly divided into four groups: the control group, TOL group that treated daily with tolvaptan (10 mg/kg/d, orally), CP group where CP was administered intraperitoneally 75 mg/kg on days 3, 4, 5, 19, 20, and 21 of study, and the CP + TOL group where animals were treated with TOL daily with (10 mg/kg/d, orally) for 22 days with concomitant administration of CP as described before. Coadministration of TOL with CP induces significant improvement in the level of urine volume, serum Na+, serum osmolarity, urinary creatinine, and free water clearance in addition to significant reduction of body weight, serum creatinine, urea, serum K+, blood pressure, urine osmolarity, and the fractional excretion of sodium as compared to CP‐treated group. In addition, coadministration of TOL significantly reduced MDA, the marker of lipid peroxidation, and different pro‐inflammatory cytokines. Histopathological changes showed improvement in the signs of nephrotoxicity with the coadministration of TOL. Also, co‐treatment with TOL significantly decreased the level of markers of apoptosis as caspase‐3 and Bax with increased expression of antiapoptotic Bcl‐2 in renal tissue as compared to CP‐treated group.

P0331ASSESSMENT OF DELIVERY OF NICE APPROVED USE OF TOLVAPTAN (JINARC) IN ADULTS WITH AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE IN A UK RENAL CENTRE

Abstract Background and Aims Until recently, the management of ADPKD has largely been limited to lifestyle changes (smoking cessation, salt avoidance and diet with weight loss) and tight blood pressure control, in addition to kidney pain management and prompt treatment of complications such as infections. The approval of Tolvaptan, a highly selective vasopressin V2 receptor antagonist, by NICE, following the pivotal TEMPO 3:4 trial provides clinicians with an opportunity to modify the progression of ADPKD and preserve kidney function. Tolvaptan works by slowing cyst growth patients with ADPKD (and therefore potentially reducing kidney pain, urinary tract infections and haematuria). During the TEMPO 3:4 trial, a reversible elevation (&amp;gt; 3X upper limit) of liver enzymes was observed in 4.4% patients taking tolvaptan vs 1% on placebo. The onset of liver injury was between 3 – 14 months of initiation of tolvaptan; therefore, monthly blood tests are required to mitigate the potential injury associated with the increase in liver enzymes. The main side effects are polyuria and thirst. The aims for the audit were Method We carried out a prospective questionnaire-based study on all patients who were on tolvaptan therapy. All patients received a comprehensive explanation of the merits and side-effects of Tolvaptan with written literature and a copy of their initial assessment consultation prior to commencement of therapy. In addition, we reviewed patients’ clinic attendances, relevant biochemical results and liver function test as per licence agreement tolvaptan therapy. This was approved by the Hull University Teaching Hospitals (HUTH) NHS Trust Audit department with a signed Clinical Governance Form 1. Results In total, 27 patients, consisting of 18 males and 9 females [mean age 44.5yrs] and all Caucasian on tolvaptan therapy were evaluated. The median duration of treatment was 10months. Two patients [7.4%] dropped out of treatment: one patient opted out of treatment due to the polyuria interfering with his job requirements and the other had relocated to another country; giving HUTH a retention rate of 92.6%. 55.5% of patients responded to not having missed a dose of drug at any time at any time despite a significant number experiencing side-affects (Figure1). Some purposely missed medication due to a social event. Although 100% of patients did respond to experiencing side effects of tolvaptan, 74% of patients said it did not interfere with their quality of life. 88.8% of patients were on the full dose of 90mg in the morning and 30mg after 8 hours. The Tolvaptan clinic in HUTH is run as a pharmacist led with consultant oversight. Currently no issues have arisen but the patients’ view of a pharmacist led-clinic is currently being studied. Conclusion This study demonstrates that despite a number of expected side-affects; with good patient education and follow-up, few patients stopped therapy and most patients remain compliant to tolvaptan therapy. Currently a pharmacist led, consultant backed tolvaptan clinic has not adversely affected this success.

P0680A POST-HOC ANALYSIS OF EFFICACY AND SAFETY OF TOLVAPTAN (TOL) IN DECREASING RATE OF RENAL FUNCTION DECLINE IN PATIENTS WITH VERY LATE-STAGE AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE (ADPKD)

Abstract Background and Aims ADPKD is a progressive inherited disease that causes end-stage renal disease (ESRD) in ∼50% of the affected individuals by 60 years of age. TOL, a selective vasopressin V2-receptor antagonist, has been shown in randomized, placebo-controlled trials to slow the progression of renal function decline in ADPKD subjects with an eGFR of 25 mL/min/1.73m2 or higher. The efficacy and safety of TOL in subjects with lower eGFR remain understudied. This post-hoc analysis evaluated the efficacy and safety of TOL in subjects with stage 4 ADPKD (eGFR of &amp;lt;30 mL/min/1.73m2). Method This is a retrospective analysis of a subgroup of ADPKD subjects who enrolled in the TOL long-term open-label extension (OLE) trial (NCT02251275). Included subjects had a baseline eGFR of &amp;lt;30 mL/min/1.73m2, received ≥ 1 TOL dose, and were randomized to the placebo group in the REPRISE trial (NCT02160145). Two subgroups of subjects were analyzed, one with baseline eGFR of 25-30 (Subgroup 1) and one with &amp;lt;25 (Subgroup 2). The variables evaluated included: 1) demographics, 2) adverse event (AE) profile, 3) intra-subject comparison of change in annualized eGFR decline during the open-label study (treatment period) to that during placebo use in the REPRISE trial (control period). Annualized eGFR change slopes in the treatment period were calculated using eGFR values between Month 1 and 12 visits to compensate for the acute hemodynamic effect of tolvaptan. Comparison was made by linear mixed model. Results Of the 1,803 subjects enrolled, 159 (8.8%) subjects (76 in Subgroup 1 and 83 in Subgroup 2) met the selection criteria for analysis. Annualized eGFR change slopes for all subjects (n=148) were -5.28 (SE 0.27) in the control period and -3.16 (SE 0.30) in the treatment period with a treatment effect of 2.11 mL/min/1.73m2/year (95% CI 1.56, 2.66), p&amp;lt;0.0001). Demographic information, baseline eGFR, treatment duration and effects in the 2 subgroups are shown in the Table below. Treatment-emergent AEs were observed in 95% and 90% of the subjects in the 2 subgroups, respectively. Discontinuation due to AEs occurred in 15% and 17% of the 2 subgroups, respectively. The 5 most common AEs for all subjects were thirst (32%), polyuria (30%), renal pain (25%), blood creatinine increase (23%) and nocturia (22%); the rates were similar between the 2 subgroups. One incidence of hepatic enzyme increase, hemodialysis and death (unrelated to TOL) was observed in Subgroup 2, but not in Subgroup 1. Conclusion This post-hoc analysis demonstrated that TOL significantly decreases the rate of eGFR decline in ADPKD subjects with stage 4 CKD, including those with an eGFR of &amp;lt;25 mL/min/1.73m2.

Clinical implications with tolvaptan on monitored bioimpedance-defined fluid status in patients with cirrhotic ascites: an observational study

BackgroundPrognostic value or clinical implications of fluid status monitoring in liver cirrhosis are not fully elucidated. Tolvaptan, an orally available, selective vasopressin V2-receptor antagonist approved for hyponatremia in the United States and European Union. It is also used for cirrhotic ascites at a relatively low dose (3.75 mg to 7.5 mg) in Japan, exerts its diuretic function by excreting electrolyte-free water. We hypothesized that bioimpedance-defined dynamic changes in fluid status allow prediction of response of V2 antagonism and survival in cirrhotic patients.MethodsIn this prospective observational study, 30 patients with decompensated liver cirrhosis who were unresponsive to conventional diuretics were enrolled. Detailed serial changes of body composition that were assessed by using non-invasive bioimpedance analysis (BIA) devices, along with biochemical studies, were monitored at 5 time points.ResultsSixteen patients were classified as short-term responders (53%). Rapid and early decrease of BIA-defined intracellular water, as soon as 6 h after the first dose (ΔICWBIA%-6 h), significantly discriminated responders from non-responders (AUC = 0.97, P < 0.0001). ΔICWBIA%-6 h was highly correlated with the change of BIA-derived phase angle of trunk, e.g. reduced body reactance operated at 50 kHz after 24 h of the first dose of tolvaptan. Lower baseline blood urea nitrogen and lower serum aldosterone were predictive of a rapid and early decrease of ICWBIA. A rapid and early decrease of ICWBIA in response to tolvaptan was also predictive of a better transplant-free survival.ConclusionsBIA-defined water compartment monitoring may help predict short-term efficacy and survival in decompensated cirrhotic patients treated with tolvaptan.

Daily Monitoring of Serum Wisteria floribunda Agglutinin-Positive Mac-2 Binding Protein Is Useful for Predicting Therapeutic Effect of Tolvaptan in Cirrhotic Ascites.

Wisteria floribunda agglutinin (WFA) is a lectin that binds to the sugar chain of Mac-2 binding protein (M2BP), and WFA-positive M2BP (WFA+-M2BP) has been reported as a useful marker for assessing liver fibrosis in chronic liver disease. Tolvaptan (TLV), a selective vasopressin V2 receptor antagonist, is used for cirrhotic ascites in Japan, but good predictors of treatment efficacy remain to be established. Our aim was to investigate whether WFA+-M2BP monitoring before and after TLV administration can predict treatment efficacy in patients with cirrhotic ascites. Twenty patients (10 men), with a median age of 72 years, were enrolled. Cirrhosis was caused by hepatitis B virus (n = 3), hepatitis C virus (n = 4), alcohol (n = 8), and others (n = 5). Responders were defined as having a body weight loss of ≥ 1.5 kg/week after TLV administration. Serum WFA+-M2BP levels were measured at baseline and days 1, 3, and 7 after TLV treatment. Twelve patients (60%) were responders. Baseline WFA+-M2BP levels were correlated with serum albumin levels (r = -0.544, P = 0.013). The baseline furosemide dose was lower and platelet count was higher in responders than in non-responders (P < 0.05). The ratio of WFA+-M2BP levels on day 1 after TLV administration to baseline was lower in responders than in non-responders (P < 0.05). The decrease in the ratio discriminated responders from non-responders (AUC = 0.844, P < 0.05). In conclusion, monitoring serum WFA+-M2BP is helpful for predicting the efficacy of TLV treatment in patients with cirrhotic ascites.

Lixivaptan, a New Generation Diuretic, Counteracts Vasopressin-Induced Aquaporin-2 Trafficking and Function in Renal Collecting Duct Cells.

Vasopressin V2 receptor (V2R) antagonists (vaptans) are a new generation of diuretics. Compared with classical diuretics, vaptans promote the excretion of retained body water in disorders in which plasma vasopressin concentrations are inappropriately high for any given plasma osmolality. Under these conditions, an aquaretic drug would be preferable over a conventional diuretic. The clinical efficacy of vaptans is in principle due to impaired vasopressin-regulated water reabsorption via the water channel aquaporin-2 (AQP2). Here, the effect of lixivaptan—a novel selective V2R antagonist—on the vasopressin-cAMP/PKA signaling cascade was investigated in mouse renal collecting duct cells expressing AQP2 (MCD4) and the human V2R. Compared to tolvaptan—a selective V2R antagonist indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia—lixivaptan has been predicted to be less likely to cause liver injury. In MCD4 cells, clinically relevant concentrations of lixivaptan (100 nM for 1 h) prevented dDAVP-induced increase of cytosolic cAMP levels and AQP2 phosphorylation at ser-256. Consistent with this finding, real-time fluorescence kinetic measurements demonstrated that lixivaptan prevented dDAVP-induced increase in osmotic water permeability. These data represent the first detailed demonstration of the central role of AQP2 blockade in the aquaretic effect of lixivaptan and suggest that lixivaptan has the potential to become a safe and effective therapy for the treatment of disorders characterized by high plasma vasopressin concentrations and water retention.

Tolvaptan: A Review in Autosomal Dominant Polycystic Kidney Disease.

Tolvaptan [Jynarque® (USA); Jinarc® (EU, Canada); Samsca® (Japan)] is a highly selective vasopressin V2 receptor antagonist approved for the treatment of autosomal dominant polycystic kidney disease (ADPKD). In the phaseIII TEMPO3:4 trial, 3years' treatment with tolvaptan slowed the increase in total kidney volume (TKV) and the decline in renal function relative to placebo. The composite secondary endpoint of time to investigator-assessed clinical progression also favoured tolvaptan over placebo. Although tolvaptan did not demonstrate a sustained disease-modifying effect on TKV over the longer term in the TEMPO4:4 extension trial, the effect of tolvaptan in slowing renal function decline was maintained for a further 2years. The phaseIII REPRISE trial confirmed the efficacy of tolvaptan in patients with later-stage ADPKD. Most of the adverse events commonly observed with tolvaptan (e.g. polyuria, nocturia, polydipsia, thirst) are consistent with its pharmacological activity. In the TEMPO trials, tolvaptan was also associated with idiosyncratic hepatotoxicity which was reversible on discontinuation of the drug. Although the use of tolvaptan requires careful consideration and balancing of benefits and risks, it provides a valuable treatment option to slow the progression of ADPKD in patients at risk of or with evidence of rapidly progressing disease.

Utilization and budget impact of tolvaptan in the inpatient setting among patients with heart failure and hyponatremia

Objective: Assess characteristics of patients with heart failure (HF) and hyponatremia (HN) using tolvaptan, a selective vasopressin V2-receptor antagonist, for sodium correction, and estimate the budget impact of tolvaptan use in a hospital.Methods: The Premier hospital database was analyzed to assess the utilization of tolvaptan, characteristics of users and non-users, and hospitalization costs among patients with HF and HN. Using these findings, a model was developed to estimate tolvaptan costs in proportion to total medical costs of managing patients with HF and HN, and the budget impact of tolvaptan use. Results were regenerated using data from the Healthcare Cost and Utilization Project (HCUP) database, and robustness was assessed in sensitivity analyses.Results: Tolvaptan was used in 4.96% of inpatient visits among patients with HF and HN, more commonly among sicker patients as reflected in high utilization during intensive care stays (30.46%). Additionally, utilization increased by length of stay, which can serve as a proxy for disease severity. The model estimated that tolvaptan costs accounted for 0.3% of total hospitalization-related costs for patients with HF and HN, and the budget impact was $52.42 per visit.Conclusions: Results demonstrate that tolvaptan is used infrequently among patients with HF and HN, and is utilized among sicker patients. Tolvaptan accounted for 0.3% of total spending on management of inpatient visits with HF and HN, and had a marginal impact on hospital budget when compared with fluid restriction for HN correction. Availability of tolvaptan can provide an additional therapeutic option for sodium correction.

Tolvaptan in the treatment of autosomal dominant polycystic kidney disease: patient selection and special considerations.

Standard of care therapies for autosomal dominant polycystic kidney disease (ADPKD) may limit morbidity and mortality due to disease-related complications, but they do not delay disease progression. Tolvaptan, a selective vasopressin V2 receptor antagonist, delays the increase in kidney volume (a surrogate marker for disease progression), slows the decline in renal function, and reduces pain in ADPKD patients with relatively preserved renal function. The most common adverse events of tolvaptan are linked to its aquaretic effect, and rare cases of idiosyncratic hepatitis were observed. Additional ongoing studies will determine whether the benefits are sustained over time, whether they can be observed in patients with advanced kidney disease, and whether they can be translated in terms of quality of life and cost/effectiveness parameters. Tolvaptan is currently approved in Europe and several countries throughout the world. In real-life conditions, selection of patients that would be good theoretical candidates to tolvaptan is a key but complex question. Eligibility criteria slightly differ from one country to another, and several models (based on conventional data, genetics, renal volume) were recently proposed to identify patients with evidence or risk of rapid disease progression. Eligible patients will ultimately make the decision to start tolvaptan, after complete information, consideration, and balancing of benefits, adverse events, and risks.

The V2 receptor antagonist tolvaptan raises cytosolic calcium and prevents AQP2 trafficking and function: an in vitro and in vivo assessment.

Tolvaptan, a selective vasopressin V2 receptor antagonist, is a new generation diuretic. Its clinical efficacy is in principle due to impaired vasopressin‐regulated water reabsorption via aquaporin‐2 (AQP2). Nevertheless, no direct in vitro evidence that tolvaptan prevents AQP2‐mediated water transport, nor that this pathway is targeted in vivo in patients with syndrome of inappropriate antidiuresis (SIAD) has been provided. The effects of tolvaptan on the vasopressin–cAMP/PKA signalling cascade were investigated in MDCK cells expressing endogenous V2R and in mouse kidney. In MDCK, tolvaptan prevented dDAVP‐induced increase in ser256‐AQP2 and osmotic water permeability. A similar effect on ser256‐AQP2 was found in V1aR −/− mice, thus confirming the V2R selectively. Of note, calcium calibration in MDCK showed that tolvaptan per se caused calcium mobilization from the endoplasmic reticulum resulting in a significant increase in basal intracellular calcium. This effect was only observed in cells expressing the V2R, indicating that it requires the tolvaptan–V2R interaction. Consistent with this finding, tolvaptan partially reduced the increase in ser256‐AQP2 and the water permeability in response to forskolin, a direct activator of adenylyl cyclase (AC), suggesting that the increase in intracellular calcium is associated with an inhibition of the calcium‐inhibitable AC type VI. Furthermore, tolvaptan treatment reduced AQP2 excretion in two SIAD patients and normalized plasma sodium concentration. These data represent the first detailed demonstration of the central role of AQP2 blockade in the aquaretic effect of tolvaptan and underscore a novel effect in raising intracellular calcium that can be of significant clinical relevance.