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Objectives: Hyponatremia (serum sodium [Na+] concentration <136 mmol/L) is a prevalent and potentially life-threatening medical comorbidity for schizophrenic patients. No definitive pharmacological treatments have been established. Tolvaptan (OPC-41061), an oral non-peptide V2-receptor antagonist, was recently shown to correct hyponatremia in a diverse population of 448 hyponatremic patients. Efficacy in a sub-set of 19 schizophrenic patients with idiopathic hyponatremia included in that sample is specifically examined. Methods: Nineteen subjects were randomly assigned to receive placebo (n = 12) or tolvaptan (n = 7) once daily for 30 days. Dosage adjustment was based on serum Na+ changes, initially 15 mg, titratable to 30 or 60 mg. The average daily area under the curve (AUC) changes in serum Na+ from baseline to Day 4 and Day 30 were co-primary end points. Results: Increases in serum Na+ concentrations were significantly greater with tolvaptan than placebo at Day 4 (p = .0055) and at Day 30 (p < .0001). Two subjects receiving tolvaptan (28.6%) became dehydrated and experienced hypotension, and five subjects receiving placebo (41.7%) experienced symptoms associated with dilutional hyponatremia. Conclusions: These results suggest that tolvaptan effectively normalizes idiopathic hyponatremia in schizophrenic patients. Clinicians are advised to carefully monitor fluid status especially at the beginning of treatment to prevent dehydration. [Copyright &y& Elsevier]

Hyponatremia is common and is associated with a poor prognosis. Traditional management with fluid restriction is difficult to maintain, and it is often ineffective. The objective of this study was to determine the effect of tolvaptan versus fluid restriction on serum sodium concentration. The study was a prospective, multicenter, randomized, active-controlled, open-label trial. Twenty-eight hospitalized subjects with serum sodium <135 mmol/L were enrolled in the study. After a 2-day run-in period, subjects were randomized 2:1 to tolvaptan alone (n = 17) or fluid restriction (1,200 ml/day) plus placebo (n = 11). Oral tolvaptan was started at 10 mg/day and increased to 60 mg/day as needed. Treatment was continued for up to 27 days, and follow-up continued for up to 65 days. The primary end point was the normalization of serum sodium, defined as >135 mmol/L or a ≥10% increase from baseline. At the last inpatient visit, serum sodium had increased by 5.7 ± 3.2 mmol/L in the tolvaptan group and 1.0 ± 4.7 mmol/L in the fluid restriction group (p = 0.0065). No differences in adverse events were observed between the groups. In conclusion, tolvaptan appears to be more effective than fluid restriction at correcting hyponatremia in hospitalized subjects, without an increase in adverse events. [Copyright &y& Elsevier]

Several letters to the editor are presented in response to a study on the efficacy of tolvaptan for the treatment of autosomal dominant polycystic kidney disease by V. E. Torres et al., published in the December 20, 2012 issue.

Background: Hyponatremia (serum sodium concentration, <135 mmol per liter) is a predictor of death among patients with chronic heart failure and cirrhosis. At present, therapy for acute and chronic hyponatremia is often ineffective and poorly tolerated. We investigated whether tolvaptan, an orally active vasopressin V2-receptor antagonist that promotes aquaresis — excretion of electrolyte-free water — might be of benefit in hyponatremia. Methods: In two multicenter, randomized, double-blind, placebo-controlled trials, the efficacy of tolvaptan was evaluated in patients with euvolemic or hypervolemic hyponatremia. Patients were randomly assigned to oral placebo (223 patients) or oral tolvaptan (225) at a dose of 15 mg daily. The dose of tolvaptan was increased to 30 mg daily and then to 60 mg daily, if necessary, on the basis of serum sodium concentrations. The two primary end points for all patients were the change in the average daily area under the curve for the serum sodium concentration from baseline to day 4 and the change from baseline to day 30. Results: Serum sodium concentrations increased more in the tolvaptan group than in the placebo group during the first 4 days (P<0.001) and after the full 30 days of therapy (P<0.001). The condition of patients with mild or marked hyponatremia improved (P<0.001 for all comparisons). During the week after discontinuation of tolvaptan on day 30, hyponatremia recurred. Side effects associated with tolvaptan included increased thirst, dry mouth, and increased urination. A planned analysis that combined the two trials showed significant improvement from baseline to day 30 in the tolvaptan group according to scores on the Mental Component of the Medical Outcomes Study 12-item Short-Form General Health Survey. Conclusions: In patients with euvolemic or hypervolemic hyponatremia, tolvaptan, an oral vasopressin V2-receptor antagonist, was effective in increasing serum sodium concentrations at day 4 and day 30. (ClinicalTrials.gov numbers, NCT00072683 [SALT-1] and NCT00201994 [SALT-2].) N Engl J Med 2006;355:2099-112. [ABSTRACT FROM AUTHOR]

Background: The PROPKD score has been proposed to stratify the risk of progression to end-stage renal disease in autosomal dominant polycystic kidney disease (ADPKD) subjects. We aimed to assess its prognostic value in a genotyped subgroup of subjects from the Tolvaptan Phase 3 Efficacy and Safety Study in Autosomal Dominant Polycystic Kidney Disease (TEMPO3/4) trial., Methods: In the post hoc analysis, PKD1 and PKD2 were screened in 770 subjects and the PROPKD score was calculated in mutation-positive subjects (male: 1 point; hypertension <35 years: 2 points; first urologic event <35 years: 2 points; nontruncating PKD1 mutation: 2 points; truncating PKD1 mutation: 4 points). Subjects were classified into low-risk (LR; 0-3 points), intermediate-risk (IR; 4-6 points) and high-risk (HR; 7-9 points) groups., Results: The PROPKD score was calculated in 749 subjects (LR = 132, IR = 344 and HR = 273); age was inversely related to risk (LR = 43.6 years, IR = 39.5 years, HR = 36.2 years; P < 0.001). Subjects from the HR group had significantly higher height-adjusted total kidney volume (TKV) and rates of TKV growth. While baseline renal function was similar across all risk groups, the rate of estimated glomerular filtration rate (eGFR) decline significantly increased from LR to HR in the placebo group. Tolvaptan treatment effectiveness to reduce TKV growth was similar in all three risk categories. While tolvaptan significantly slowed eGFR decline in the IR (tolvaptan = -2.34 versus placebo = -3.33 mL/min/1.73 m2/year; P = 0.008) and HR groups (tolvaptan = -2.74 versus placebo = -3.94 mL/min/1.73 m2/year; P = 0.002), there was no difference in the LR group (tolvaptan = -2.35 versus placebo = -2.50 mL/min/1.73 m2/year; P = 0.72). Excluding the LR subjects from the analysis improved the apparent treatment effect of tolvaptan on eGFR decline., Conclusion: This study confirms the prognostic value of the PROPKD score and suggests that it could reduce costs and enhance endpoint sensitivity by enriching future study populations for rapidly progressing ADPKD subjects.

The vasopressin-cAMP-osmolality axis is abnormal in autosomal dominant polycystic kidney disease (ADPKD). In the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes 3:4 Trial, a 3-year randomized, placebo-controlled trial in adults, the vasopressin V2 receptor antagonist tolvaptan slowed ADPKD progression in patients with preserved GFR. Here, we investigated the determinants of baseline urine osmolality (Uosm) and its value as a severity marker of ADPKD, the factors influencing the response to tolvaptan, and whether change in Uosm associated with key trial end points. At baseline, lower Uosm independently associated with female sex, presence of hypertension, lower eGFR, higher total kidney volume (TKV), and higher age. Tolvaptan consistently reduced Uosm by 200-300 mOsm/kg over 36 months. The Uosm response to tolvaptan depended on baseline eGFR and Uosm. Subjects with greater change in Uosm experienced a significant reduction in clinical progression events. Among subjects receiving tolvaptan, those with a greater suppression of Uosm had slower renal function decline. Assessment at follow-up, off medication, revealed a significant decrease in Uosm in both placebo and treated groups. Tolvaptan significantly increased plasma osmolality, which returned to baseline at follow-up. In conclusion, baseline Uosm in ADPKD reflects age, renal function, and TKV, and baseline Uosm, eGFR, and TKV influence the effect of tolvaptan on Uosm. The greatest renal benefit occurred in subjects achieving greater suppression of Uosm, that is, those with better eGFR at baseline. These results support the link between vasopressin V2 receptor signaling and ADPKD progression., (Copyright © 2017 by the American Society of Nephrology.)

Background: and objectives The Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes 3:4 study demonstrated a significant beneficial effect of the vasopressin V2 receptor antagonist tolvaptan on rates of kidney growth and eGFR decline in autosomal dominant polycystic kidney disease (ADPKD). This post hoc analysis was performed to reassess the primary and secondary efficacy endpoints by CKD stage at baseline., Design, Setting, Participants, & Measurements: In a phase 3, multicenter, double-blind, placebo-controlled, 3-year trial, 1445 patients with ADPKD (age 18-50 years), with total kidney volume (TKV) ≥750 ml and estimated creatinine clearance ≥60 ml/min, were randomly assigned 2:1 to split-dose tolvaptan (45/15, 60/30, or 90/30 mg daily as tolerated) or placebo. The primary endpoint was annualized rate of TKV change. Secondary endpoints included a composite endpoint of time to multiple composite ADPKD-related events (worsening kidney function, kidney pain, hypertension, and albuminuria) and rate of kidney function decline., Results: Tolvaptan reduced annualized TKV growth by 1.99%, 3.12%, and 2.61% per year (all P<0.001; subgroup-treatment interaction, P=0.17) and eGFR decline by 0.40 in CKD1 (P=0.23), 1.13 in CKD2 (P<0.001) and 1.66 ml/min per 1.73 m(2) per year in CKD3 (P<0.001) with a trend for a positive subgroup-treatment interaction (P=0.07) across CKD1, CKD2 and CKD3. ADPKD-related events were less frequent in tolvaptan recipients than in placebo recipients among those with CKD1 (hazard ratio [HR], 0.83; 95% confidence interval [95% CI], 0.70-0.98; P=0.03) and those with CKD 3 (HR, 0.71; 95% CI, 0.57-0.89; P=0.003), but not among those with CKD2 (HR, 1.02; 95% CI, 0.85-1.21; P=0.86). Aquaresis-related adverse events (more frequent in the tolvaptan group) and ADPKD-related adverse events (more frequent in the placebo group) were not associated with CKD stage. Hypernatremia events in tolvaptan-treated patients with CKD3 and plasma aminotransferase elevations in tolvaptan-treated patients across CKD stages 1-3 occurred more frequently than in placebo recipients., Conclusions: This post hoc analysis suggests clinically similar beneficial effects of tolvaptan in ADPKD across CKD stages 1-3., (Copyright © 2016 by the American Society of Nephrology.)

Objective: OPC-28326 is a selective alpha-adrenergic antagonist with preferential binding to the alpha(2C)-adrenergic receptor (alpha(2C)-AR) subtype. This study observed the effect of OPC-28326 on skin temperature and digital blood flow following an acute cold challenge in patients with Raynaud's phenomenon secondary to scleroderma., Methods: The study was designed as a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of OPC-28326 (oral doses of 10 mg or 40 mg) or placebo. The primary outcome measures were the time to recover 50% and 70% of the fall (induced by cold challenge) in baseline digital skin temperature., Results: Twelve of 13 enrolled patients completed the study. The mean time to achieve 50% and 70% recovery of the change in prechallenge digital skin temperature was shorter after the OPC-28326 40-mg dose than after placebo (50% recovery at 5.8 minutes versus 10.0 minutes [P = 0.02]; 70% recovery at 13.8 minutes versus 19.5 minutes [P = 0.01]). These recovery times tended to be shorter in the 10 mg OPC-28326 group as well, but the difference versus placebo was not significant (50% recovery at 9.0 minutes versus 10.0 minutes [P = 0.65]; 70% recovery at 15.3 minutes versus 19.5 minutes [P = 0.07]). Total digital blood flow tended to be lower prior to the cold challenge and after administration of 40 mg OPC-28326, as compared with that after placebo, but the difference was not significant. Symptoms that were potentially drug-related were reported more frequently with 40 mg OPC-28326 than with 10 mg OPC-28326 or with placebo, but none were serious or sustained., Conclusion: OPC-28326 at doses of 10 mg and 40 mg was well tolerated during this study. The shorter time to skin temperature recovery after 40 mg OPC-28326 suggests that selective alpha(2C)-AR blockade improves digital skin perfusion during recovery from cooling in patients with Raynaud's phenomenon secondary to scleroderma.

Background: In this study, we evaluated the effects of tolvaptan (OPC-41061), a novel, oral, nonpeptide vasopressin V2-receptor antagonist in patients with chronic heart failure (CHF)., Methods and Results: This was a double-blind study investigating the effects of three doses of tolvaptan and placebo in patients with CHF. After a run-in period, 254 patients were randomly assigned to placebo (n=63) or tolvaptan [30 mg (n=64), 45 mg (n=64), or 60 mg (n=63)] once daily for 25 days. Patients were not fluid-restricted and were maintained on stable doses of furosemide. At day 1, when compared with baseline, a decrease in body weight of -0.79+/-0.99, -0.96+/-0.93, and -0.84+/-0.02 kg was observed in the 30-, 45-, and 60-mg tolvaptan groups, respectively, and a body weight increase of +0.32+/-0.46 kg in the placebo group (P<0.001 for all treatment groups versus placebo). Although the initial decrease in body weight was maintained during the study, no further reduction was observed beyond the first day. An increase in urine volume was observed with tolvaptan when compared with placebo (3.9+/-0.6, 4.2+/-0.9, 4.6+/-0.4, and 2.3+/-0.2 L/24 hours at day 1 for 30-, 45-, and 60-mg tolvaptan groups, and placebo, respectively; P<0.001). A decrease in edema and a normalization of serum sodium in patients with hyponatremia were observed in the tolvaptan group but not in the placebo group. No significant changes in heart rate, blood pressure, serum potassium, or renal function were observed., Conclusions: In patients with CHF, tolvaptan was well tolerated; it reduced body weight and edema and normalized serum sodium in the hyponatremic patients.