Terlipressin, a vasoactive prodrug recommended in hepatorenal syndrome, is an agonist of human V1, V2 and V1B receptors: Implications for its safety profile

Terlipressin-Associated Complete Heart Block

Terlipressin has been recently approved in the United States to treat hepatorenal syndrome, a feared complication of both acute and chronic liver diseases. Side effects of the medication have been studied through clinical trials and the precedent use in Europe, as well as extrapolation from its analog vasopressin. As its use is becoming more prevalent, unforeseen complications have arisen. We report a case of complete heart block associated with terlipressin use in presumed hepatorenal syndrome in acute liver injury.

From Pathophysiology to Practice: Evolving Pharmacological Therapies, Clinical Complications, and Pharmacogenetic Considerations in Portal Hypertension

Background: Portal hypertension is a major complication of chronic liver diseases, leading to serious issues such as esophageal variceal bleeding. The increase in portal vein pressure is driven by both an organic component and a functional component, including tonic contraction of hepatic stellate cells. These processes result in a pathological rise in intrahepatic vascular resistance, stemming from partial impairment of hepatic microcirculation, which is further exacerbated by abnormalities in extrahepatic vessels, including increased portal blood flow. Objectives: This review aims to provide a comprehensive overview of the evolving pharmacological therapies for portal hypertension, with consideration and discussion of pathophysiological mechanisms, clinical complications, and pharmacogenetic considerations, highlighting potential directions for future research. Methods: A review of recent literature was performed to evaluate current knowledge and potential therapeutic strategies in portal hypertension. Results: For over 35 years, non-selective beta-blockers have been the cornerstone therapy for portal hypertension by reducing portal vein inflow as an extrahepatic target, effectively preventing decompensation and variceal hemorrhages. However, since not all patients exhibit an adequate response to non-selective beta-blockers (NSBBs), and some may not tolerate NSBBs, alternative or adjunctive therapies that enhance the effects of NSBBs on portal pressure are being investigated in preclinical and early clinical studies. Conclusions: A better understanding of pharmacogenetic factors and pathophysiological mechanisms could lead to more individualized and effective treatments for portal hypertension. These insights highlight potential directions for future research.

Terlipressin for hepatorenal syndrome

PURPOSE OF REVIEW

The definition and diagnostic criteria of hepatorenal syndrome-acute kidney injury (HRS-AKI) has undergone recent changes. A major vasoconstrictor, terlipressin, has recently been approved as pharmacotherapy for HRS-AKI in the United States. The purpose of this review is to familiarize the readers with these new diagnostic criteria of HRS-AKI, and how best to use terlipressin.

RECENT FINDINGS

Terlipressin is effective either as bolus dosing or continuous infusion and can achieve reversal of HRS-AKI in approximately 40% of patients. Continuous infusion allows lower daily dose with equal efficacy and less side effects but not an approved mode of administration in the United States. Response to terlipressin in the randomized controlled trials was defined as repeat reduction of serum creatinine to less than 1.5 mg/dl. Newer studies will likely require response to treatment to be defined as a repeat serum creatinine to be less than 0.3 mg/dl from baseline. Terlipressin use is associated with ischemic side effects and potential for respiratory failure development.

SUMMARY

Careful patient selection and close monitoring are necessary for its use. Response to terlipressin with HRS-AKI reversal is associated with improved outcomes with better survival and less requirement for renal replacement therapy.

Hepatorenal Syndrome Type 1: Diagnosis and Treatment

Hepatorenal syndrome (HRS) is a feared complication in patients with advanced cirrhosis and is associated with significant morbidity and mortality. While recognized as a distinct physiologic condition for well over one hundred years, a lack of objective diagnostic tests has made the diagnosis one of exclusion. Since 1979, multiple sets of diagnostic criteria have been proposed. Though varying in detail, the principal intent of these criteria is to identify patients with severe, functional acute kidney injury that is unresponsive to volume resuscitation and exclude those with structural injury. However, accurate differential diagnosis remains challenging. Recently, multiple urinary biomarkers of kidney injury, including neutrophil gelatinase-associated lipocalin, have been studied as a means of objectively phenotyping etiologies of acute kidney injury in patients with cirrhosis. Along with markers reflecting tubular functional integrity, including the fractional excretion of sodium, injury markers will likely be incorporated into future diagnostic criteria. Making an accurate diagnosis is critical, as therapeutic options exist for HRS but must be given in a timely manner and only to those patients likely to benefit. Terlipressin, an analog of vasopressin, is the first line of therapy for HRS in much of the world and has recently been approved for use in the United States. Significant questions remain regarding the optimal dosing strategy, metrics for titration, and the potential role of point-of-care ultrasound to help guide concurrent albumin administration.

OCE-205 in rats and non-human primates: Pharmacokinetic and pharmacodynamic analysis

Treatment for complications associated with the hemodynamic consequences of decompensated cirrhosis remains suboptimal. Terlipressin, the latest pharmacological management of hepatorenal syndrome-acute kidney injury (HRS-AKI), targets the vasopressin system but has serious side effects. OCE-205 is a novel peptide designed to target the vasopressin receptor system as a mixed V1a agonist/antagonist, resulting in effective partial agonism without V2 agonism. We examined the in vivo pharmacokinetic/pharmacodynamic properties of OCE-205 in healthy rats and cynomolgus monkeys. OCE-205 was administered by IV or SC bolus injection; arginine vasopressin (AVP) or terlipressin were comparators. After IV OCE-205 administration in rats, mean plasma concentration decreased in a mostly linear manner to 2 mg/mL after 120 min, and for SC administration, slowly decreased to ∼50 ng/mL after 300 min. Compared with pre-test values, arterial blood pressure values significantly increased after all OCE-205 doses tested. For monkeys, the concentration after IV OCE-205 administration was mostly linear to 5 ng/mL after 180 min, and for SC administration, ∼3 ng/mL after 480 min. Subcutaneous OCE-205 administration increased mean arterial pressure (MAP) versus baseline, with ΔMAP in OCE-205-treated animals marked and long-lasting while terlipressin induced an increase from baseline in MAP, with negligible ΔMAP, on average, by 150 min after administration in all groups. AVP, but not OCE-205, significantly increased blood lactate concentrations. OCE-205 was well tolerated in adult male rats and cynomolgus monkeys following single-dose bolus administration. The preclinical results of OCE-205, with its demonstrated V1a selective partial agonist activity and potentially tolerable safety profile, suggest its potential utility for treatment of the cardiovascular complications of cirrhosis.

Institutional protocol number

Procedures were approved by the Ferring Research Institute (FRI) Institutional Animal Care and Use Committee (IACUC) on November 27, 2006 under protocol FRI 06-011, and by the Sinclair Research Center IACUC under protocol S11177.

Acute Kidney Injury in Liver Cirrhosis

Acute kidney injury (AKI) is common in cirrhotic patients affecting almost 20% of these patients. While multiple etiologies can lead to AKI, pre-renal azotemia seems to be the most common cause of AKI. Irrespective of the cause, AKI is associated with worse survival with the poorest outcomes observed in those with hepatorenal syndrome (HRS) and acute tubular necrosis (ATN). In recent years, new definitions, and classifications of AKI in cirrhosis have emerged. More knowledge has also become available regarding the benefits and drawbacks of albumin and terlipressin use in these patients. Diagnostic tools such as urinary biomarkers and point-of-care ultrasound (POCUS) became available and they will be used in the near future to differentiate between different causes of AKI and direct management of AKI in these patients. In this update, we will review these new classifications, treatment recommendations, and diagnostic tools for AKI in cirrhotic patients.

OCE-205, a Selective V1a Partial Agonist, Reduces Portal Pressure in Rat Models of Portal Hypertension

Purpose

Management of decompensated cirrhosis may include the use of vasoconstrictors that can lead to serious adverse events. OCE-205 was designed as a highly selective V1a receptor partial agonist, intended to have a wider therapeutic window than full vasopressin agonists.

Methods

We aimed to characterize the activity of OCE-205 treatment in two rat models of portal hypertension (PHT). For both models, OCE-205 was administered as a subcutaneous bolus injection. Thirty male Wistar rats were fed a methionine/choline-deficient (MCD) diet to model PHT. Animals received OCE-205 (10, 25, 100, or 500 µg/kg) or intra-arterial terlipressin (100 µg/kg). In a more severe model of PHT, 11 male Sprague Dawley rats had the common bile duct surgically ligated (BDL) and received OCE-205. Portal pressure (PP) and mean arterial pressure (MAP) were measured.

Results

For PP in the MCD model, MAP increased while PP decreased in rats treated with OCE-205 or terlipressin; the peak changes to MAP were 14.7 and 33.5 mmHg, respectively. Changes in MAP began to plateau after 10 min in the OCE-205 groups, whereas in the terlipressin group, MAP rapidly increased and peaked after 20 min. Across all treatment groups in the BDL model, a dose-related decrease from baseline in PP was observed following OCE-205, plateauing as the dose increased. In all treatment groups, PP change remained negative throughout the 30-min testing period. In both PHT rat models, a reduction in PP was coupled to an increase in MAP, with both plateauing in dose-response curves.

Conclusion

Data support OCE-205 as a promising candidate for further development.

Institutional Protocol Number

Procedures were approved by the Ferring Research Institute (FRI) Institutional Animal Care and Use Committee on July 13, 2011, under protocol FRI-07-0002.

Hepatorenal Syndrome: Pathophysiology, Diagnosis, and Treatment

Hepatorenal syndrome (HRS) is a primarily functional form of acute kidney injury (AKI) that develops in patients with decompensated cirrhosis. The pathophysiologic cascade that leads to HRS begins with pooling of blood in the splanchnic system, resulting in a decrease in effective circulating arterial volume. The definitive treatment of HRS is liver transplantation. When this is not possible, HRS is treated with a combination of vasoconstrictor agents and intravenous albumin. Although the combination of midodrine and octreotide is used in the United States, the recently approved terlipressin, an analog of vasopressin, is likely to become the first-line standard of care.

Role of Terlipressin in Patients With Hepatorenal Syndrome-Acute Kidney Injury Admitted to the ICU: A Substudy of the CONFIRM Trial

This study assessed the potential advantages of treating hepatorenal syndrome-acute kidney injury (HRS-AKI) with terlipressin versus placebo in the ICU setting.

DESIGN

Patients were randomly assigned in a 2:1 ratio to receive terlipressin or placebo for up to 14 days.

SETTING

A retrospective analysis of data from the phase III CONFIRM study.

PARTICIPANTS

Adult patients with HRS-AKI admitted to the ICU.

MAIN OUTCOMES AND MEASURES

In this substudy, we evaluated outcomes of the ICU stay and the need for organ support, including renal replacement therapy (RRT).

RESULTS

Among 300 patients with HRS-AKI from the CONFIRM study, 45 were treated in the ICU (terlipressin, 31/199 [16%]; placebo, 14/101 [14%]). On ICU admission, baseline demographics were similar across treatment arms, including severity of liver dysfunction. Among patients alive at the end of the ICU stay, those randomized to terlipressin had a significantly shorter median length of ICU stay than placebo (4 vs 11 d; p < 0.001). Terlipressin-treated patients had a significantly larger improvement in renal function from baseline versus placebo (-0.7 vs +0.2 mg/dL; p = 0.001), including when accounting for the interaction between treatment and day-of-patient-admission to the ICU (-0.7 vs +0.9 mg/dL; p < 0.001). Cumulative requirement for RRT through day 90 was improved in the terlipressin arm versus placebo (10/31 [32%] vs 8/14 [57%]; p = 0.12), although not significantly. Of 13 patients who received a liver transplant, five out of five (100%) in the placebo arm needed RRT through day 90 versus five out of eight (63%) in the terlipressin arm.

CONCLUSIONS

In this subanalysis of CONFIRM, patients admitted to the ICU with HRS-AKI who received terlipressin were more likely to achieve renal function improvement, based on serum creatinine changes by the end of treatment, and had significantly shorter lengths of ICU stay than patients randomized to the placebo arm.

Involvement of Vasopressin in Tissue Hypoperfusion during Cardiogenic Shock Complicating Acute Myocardial Infarction in Rats

Acute heart failure (AHF) due to acute myocardial infarction (AMI) is likely to involve cardiogenic shock (CS), with neuro-hormonal activation. A relationship between AHF, CS and vasopressin response is suspected. This study aimed to investigate the implication of vasopressin on hemodynamic parameters and tissue perfusion at the early phase of CS complicating AMI. Experiments were performed on male Wistar rats submitted or not to left coronary artery ligation (AMI and Sham). Six groups were studied Sham and AMI treated or not with either a vasopressin antagonist SR-49059 (Sham-SR, AMI-SR) or agonist terlipressin (Sham-TLP, AMI-TLP). Animals were sacrificed one day after surgery (D₁) and after hemodynamic parameters determination. Vascular responses to vasopressin were evaluated, ex vivo, on aorta. AHF was defined by a left ventricular ejection fraction below 40%. CS was defined by AHF plus tissue hypoperfusion evidenced by elevated serum lactate level or low mesenteric oxygen saturation (SmO₂) at D₁. Mortality rates were 40% in AMI, 0% in AMI-SR and 33% in AMI-TLP. Immediately after surgery, a sharp decrease in SmO₂ was observed in all groups. At D₁, SmO₂ recovered in Sham and in SR-treated animals while it remained low in AMI and further decreased in TLP-treated groups. The incidence of CS among AHF animals was 72% in AMI or AMI-TLP while it was reduced to 25% in AMI-SR. Plasma copeptin level was increased by AMI. Maximal contractile response to vasopressin was decreased in AMI (32%) as in TLP- and SR- treated groups regardless of ligation. Increased vasopressin secretion occurring in the early phase of AMI may be responsible of mesenteric hypoperfusion resulting in tissue hypoxia. Treatment with a vasopressin antagonist enhanced mesenteric perfusion and improve survival. This could be an interesting therapeutic strategy to prevent progression to cardiogenic shock.

Pharmacokinetic and pharmacodynamic analyses of terlipressin in patients with hepatorenal syndrome

The objective of this population pharmacokinetics (PK) analysis was to characterize the PK of terlipressin and its active metabolite, lysine-vasopressin (L-VP), in patients with hepatorenal syndrome (HRS), following intravenous administration of terlipressin 1 mg to 2 mg every 6 h. Sparse PK samples from 69 patients with HRS who participated in terlipressin phase 3 clinical studies were used for model development. In addition, mean arterial pressure (MAP) and heart rate (HR) from 40 patients with HRS were available to explore the relationship between terlipressin and L-VP plasma concentrations and pharmacodynamic (PD) response. A two-compartment model with first-order elimination adequately described the PK of terlipressin. L-VP was well characterized as the active metabolite of terlipressin by a one-compartment model with first-order elimination. The population PK modeling results showed that the estimated clearances for terlipressin and L-VP are 27.4 L/h and 318 L/h, respectively, for a typical patient with a body weight of 86 kg. Body weight was identified as the only covariate for the clearance of terlipressin. However, simulation suggested that body weight had no clinically meaningful effects on the exposure of L-VP through terlipressin. Therefore, no weight-based dose is needed for terlipressin to treat HRS patients. PD response, change in MAP, and HR were well correlated to L-VP concentrations; compared with baseline values, the estimated maximum decrease in HR would be 10.6 bpm and the estimated maximum increase in MAP would be 16.2 mm Hg.

Terlipressin and the Treatment of Hepatorenal Syndrome: How the CONFIRM Trial Moves the Story Forward

Hepatorenal syndrome (HRS) is a form of acute kidney injury occurring in patients with advanced cirrhosis and is associated with significant morbidity and mortality. The pathophysiology underlying HRS begins with increasing portal pressures leading to the release of vasodilatory substances which result in pooling blood in the splanchnic system and a corresponding reduction in effective circulating volume. Compensatory activation of the sympathetic nervous system, renin-angiotensin-aldosterone system and release of arginine vasopressin serve to defend mean arterial pressure but at the cost of severe constriction of the renal vasculature, leading to a progressive, often fulminant form of AKI. While there are no approved treatments for HRS in the United States, multiple countries, including much of Europe, utilize terlipressin, a synthetic vasopressin analogue, as first-line therapy. The recently published CONFIRM trial, the third randomized trial based in North America evaluating terlipressin, met its primary endpoint, showing greater rates of HRS reversal in the terlipressin arm. However, due to concerns about apparent increased rates of respiratory adverse events and a lack of evidence for mortality benefit, terlipressin was not approved by the Food and Drug Administration (FDA). In this Perspective, we explore the history of regulatory approval for terlipressin in the United States, examine the results from CONFIRM and the concerns they raised and consider the future role of terlipressin in this critical clinical area of continued unmet need.

Juvenile-onset gout and adipsic diabetes insipidus: A case report and literature review

The prevalence of juvenile-onset gout has been increasing. Hereditary factors and secondary diseases should be considered in these patients. Adipsic diabetes insipidus (ADI) is characterized by arginine vasopressin (AVP) deficiency, which results in hypotonic polyuria, and dysfunction of thirst osmoreceptors, which results in failure to generate a thirst sensation in response to hypernatremia. We herein report a case of a boy with gouty arthritis, refractory hyperuricemia, prominent hypernatremia, a high creatinine concentration, and a history of surgery for a hypothalamic hamartoma. The patient was diagnosed with central diabetes insipidus after endocrine evaluation. Because he never had symptoms of thirst, the final diagnosis was corrected to ADI. This is the first report of gout due to chronic ADI in an adolescent. Volume contraction due to ADI might be one cause of hyperuricemia and renal impairment in such patients. Moreover, AVP deficiency might directly lead to low urate clearance due to the lack of vasopressin receptor 1 stimulation. Lack of polydipsia and polyuria may delay the diagnosis of ADI and lead to severe complications of a chronic hyperosmolar status. Sufficient and effective establishment of normovolemia is critical for these patients.

Terlipressin-induced modifications of Doppler ultrasound signals of systemic arteries in preterm infants with vasoactive-resistant patent ductus arteriosus: A pilot study

PURPOSE

To study the effects of terlipressin (TP) infusion on systemic perfusion, estimated with pulsed-wave Doppler ultrasonography of systemic arteries, in a population of extremely low birth-weight (ELBW) preterm infants with vasoactive-resistant ductus arteriosus.

METHODS

This prospective, observational cohort included, during five years, 12 ELBW infants with hemodynamically significant patent ductus arteriosus and absent or reversed diastolic flow at Doppler ultrasonography of systemic arteries, despite treatment and high-dose vasoactive support. We measured flow velocity of the anterior cerebral, right renal, and superior mesenteric arteries before and after TP infusion. Changes were evaluated by Spearman's rho coefficient analysis, Wilcoxon signed-rank, and Friedman test.

RESULTS

Time-averaged mean velocity of the renal artery (P = .028) increased, while renal pulsatility (P = .010) and resistance (P = .004) indexes, and cerebral artery resistance index (P = .021) decreased after TP infusion. Time-averaged mean velocity of the anterior cerebral artery proportionately increased with dopamine dose (rho = 0.678; P = .015), but showed opposite shifts after TP (rho = -0.662; P = .024).

CONCLUSIONS

These changes suggest that TP may improve systemic perfusion in the ELBW infants with vasoactive-resistant ductus arteriosus.

In vitro binding and receptor-mediated activity of terlipressin at vasopressin receptors V1 and V2

Terlipressin, a synthetic, systemic vasoconstrictor with selective activity at vasopressin-1 (V₁) receptors, is a pro-drug for the endogenous/natural porcine hormone [Lys₈]-vasopressin (LVP). We investigated binding and receptor-mediated cellular activities of terlipressin, LVP, and endogenous human hormone [Arg₈]-vasopressin (AVP) at V₁ and vasopressin-2 (V₂) receptors. Cell membrane homogenates of Chinese hamster ovary cells expressing human V₁ and V₂ receptors were used in competitive binding assays to measure receptor-binding activity. These cells were used in functional assays to measure receptor-mediated cellular activity of terlipressin, LVP, and AVP. Binding was measured by [³H]AVP counts, and the activity was measured by fluorometric detection of intracellular calcium mobilization (V₁) and cyclic adenosine monophosphate (V₂). Binding potency at V₁ and V₂ was AVP>LVP>>terlipressin. LVP and terlipressin had approximately sixfold higher affinity for V₁ than for V₂. Cellular activity potency was also AVP>LVP>>terlipressin. Terlipressin was a partial agonist at V₁ and a full agonist at V₂; LVP was a full agonist at both V₁ and V₂. The in vivo response to terlipressin is likely due to the partial V₁ agonist activity of terlipressin and full V₁ agonist activity of its metabolite, LVP. These results provide supportive evidence for previous findings and further establish terlipressin pharmacology for vasopressin receptors.

Dual Organ Duel: The Hepatorenal Axis

Recent developments in our understanding of the pathogenesis of kidney disease in the setting of liver failure have highlighted that kidney injury, rather than occurring in isolation, is a marker of systemic disease and poor prognosis. The differential diagnosis of kidney disease associated with liver failure is broader than formerly described and new biopsy data, along with better acute kidney injury classification tools, have increased appreciation for distinct pathophysiological mechanisms. Evidence suggests that acute kidney injury contributes to worsening hepatic failure by directly injuring hepatic cells and by imposing restrictions on therapeutic strategies for portal hypertension. Furthermore, kidney injury limits the use of various therapeutic agents and increases their toxicity due to altered pharmacodynamics. A greater appreciation of CKD in this population is also overdue because management decisions are affected and increased vigilance may avoid further kidney injury. A multidisciplinary approach to kidney injury in the setting of liver failure will enable targeted therapeutic strategies that are safe and effective and serve to guide further research, while limiting clinical potential for harm. Finally, new hepatitis C antiviral therapies promise to change the landscape of liver failure, and a discussion of kidney risk factors and antiviral therapy of patients with kidney disease and hepatitis C is worthwhile.