Population Pharmacokinetic and Pharmacodynamic Modeling of Lusutrombopag, a Newly Developed Oral Thrombopoietin Receptor Agonist, in Healthy Subjects

A single course of lusutrombopag for multiple invasive procedures in cirrhosis-associated thrombocytopenia: A case series

RATIONALE

Lusutrombopag is a thrombopoietin receptor agonist which reduces the need for platelet transfusions before planned invasive procedures. A post hoc analysis of data from the registration trials observed that lusutrombopag-treated patients who achieved a platelet count > 50 × 109/L (responder patients) did so in a median of 6 days and the effect on platelet count lasted for nearly 3 weeks in total. Since patients with cirrhosis often require repeat invasive procedures, this kind of response-time trend sheds light on the possibility of placing more than one invasive procedure within a single course of lusutrombopag treatment.

PATIENT CONCERNS

Platelet transfusion represents the gold standard in this setting, but is limited by the risk of adverse events and limited availability.

DIAGNOSES

We describe our experience with lusutrombopag in three patients with severe cirrhosis-associated thrombocytopenia who underwent multiple invasive procedures after a single course of treatment.

INTERVENTIONS

The treatment schedule is lusutrombopag orally 3 mg/daily for 7 days and then a time window of 6 days (day 9-14) for the elective invasive procedure.

OUTCOMES

All three patients achieved good response to lusutrombopag treatment and were able to undergone more invasive procedures in the same course of treatment without need of platelet transfusion.

LESSONS

our preliminary experience supports the safety and the effectiveness of lusutrombopag in patients with severe cirrhosis-associated thrombocytopenia who underwent multiple invasive elective procedures after a single course.

Systematic Review with Meta-Analysis: Efficacy and Safety of Lusutrombopag for Severe Thrombocytopenia in Patients with Chronic Liver Disease Undergoing Invasive Procedures

INTRODUCTION

Lusutrombopag is an oral thrombopoietin receptor agonist (TPO-RA). Clinical trials have shown lusutrombopag's efficacy in reducing need for preoperative platelet transfusion in patients with chronic liver disease (CLD) and severe thrombocytopenia. This analysis assessed efficacy and safety of lusutrombopag in patients with severe thrombocytopenia and CLD undergoing planned invasive procedures.

METHODS

An electronic database search (through 1 December 2020) identified three randomised, placebo-controlled, double-blind clinical trials comparing lusutrombopag with placebo in patients with CLD and platelet count below 50 × 109/L scheduled to undergo a procedure with a perioperative bleeding risk. A random-effects meta-analysis examined treatment effect, with Cochrane Collaboration's tool assessing risk of bias.

RESULTS

The meta-analysis included 343 (lusutrombopag 3 mg, n = 173; placebo, n = 170) patients. More patients met the criteria for treatment response (platelet count at least 50 × 109/L and increase of at least 20 × 109/L from baseline anytime during the study) with lusutrombopag versus placebo (risk ratio [RR] 6.39; 95% confidence interval [CI] 3.69, 11.07; p < 0.0001). The primary efficacy outcome, proportion of patients requiring no platelet transfusion and no rescue therapy for bleeding for at least 7 days post procedure, was achieved by more patients treated with lusutrombopag versus placebo (RR 3.42; 95% CI 1.86, 6.26; p = 0.0001). The risk of any bleeding event was significantly lower with lusutrombopag compared to placebo (RR 0.55; 95% CI 0.32, 0.95; p = 0.03); conversely, thrombosis event rates were similar between lusutrombopag and placebo (RR 0.79; 95% CI 0.19, 3.24; p = 0.74).

CONCLUSION

This meta-analysis showed that treatment of severe thrombocytopenia with lusutrombopag in patients with CLD prior to a planned invasive procedure was efficacious and safe in increasing platelet counts, avoiding the need for platelet transfusions, and reducing risk of bleeding, thereby enhancing the certainty of evidence supporting the efficacy and safety of lusutrombopag.

Thrombocytopenia in chronic liver disease: Physiopathology and new therapeutic strategies before invasive procedures

Chronic liver disease is characterized by several hematological derangements resulting in a complex and barely rebalanced haemostatic environment. Thrombocytopenia is the most common abnormality observed in these patients and recent advances have led to researchers focus the attention on the multifactorial origin of thrombocytopenia and on the key role of thrombopoietin (TPO) in its physiopathology. Severe thrombocytopenia (platelet count < 50000/μL) complicates the management of patients with chronic liver disease by increasing the potential risk of bleeding for invasive procedures, which may be therefore delayed or canceled even if lifesaving. In the very last years, the development of new drugs which exceed the limits of the current standard of care (platelet transfusions, either immediately before or during the procedure) paves the way to a new scenario in the management of this population of patients. Novel agents, such as the TPO-receptor agonists avatrombopag and lusutrombopag, have been developed in order to increase platelet production as an alternative to platelet transfusions. These agents have demonstrated a good profile in terms of efficacy and safety and will hopefully allow reducing limitations and risks associated with platelet transfusion, without any delay in scheduled interventions. Altogether, it is expected that patients with chronic liver disease will be able to face invasive procedures with one more string in their bow.

Generation of a thrombopoietin-deficient thrombocytopenia model in zebrafish

BACKGROUND

The production of platelets is tightly regulated by thrombopoietin (THPO). Mutations in the THPO gene cause thrombocytopenia. Although mice lacking Thpo present with thrombocytopenia, predicting phenotypes and pathogenicity of novel THPO mutations in mice is limited. Zebrafish can be a powerful tool for fast validation and study of candidate genes of human hematological diseases and have already been used as a model of human thrombocytopenia.

OBJECTIVES

We aim to investigate the role of Thpo in zebrafish thrombopoiesis and to establish a Thpo-deficient zebrafish model. The model could be applied for illustrating the clinically discovered human THPO variants of which the clinical significance is not known and to evaluate the effect of THPO receptor agonists (THPO-Ras), as well as a screening platform for new drugs.

METHODS

We generated a thpo loss-of-function zebrafish model using CRISPR/Cas9. After disruption of zebrafish thpo, thposzy6 zebrafish presented with a significant reduction of thpo expression and developed thrombocytopenia. Furthermore, we performed in vivo studies with zebrafish with the thposzy6 mutation and found two human clinical point mutations (c.091C > T and c.112C > T) that were responsible for the thrombocytopenia phenotype. In addition, effects of THPO-RAs used as therapeutics against thrombocytopenia were evaluated in the Tg(mpl:eGFP);thposzy6 line.

RESULTS AND CONCLUSIONS

Zebrafish with the mutation thposzy6 presented with a significant reduction of thpo expression and developed thrombocytopenia. Thpo loss-of-function zebrafish model can serve as a valuable preclinical model for thrombocytopenia caused by thpo-deficiency, as well as a tool to study human clinical THPO variants and evaluate the effect of THPO-RAs.

Evaluation of covariate effects using variance-based global sensitivity analysis in pharmacometrics

In pharmacometrics, understanding a covariate effect on an interested outcome is essential for assessing the importance of the covariate. Variance-based global sensitivity analysis (GSA) can simultaneously quantify contribution of each covariate effect to the variability for the interested outcome considering with random effects. The aim of this study was to apply GSA to pharmacometric models to assess covariate effects. Simulations were conducted with pharmacokinetic models to characterize the GSA for assessment of covariate effects and with an example of quantitative systems pharmacology (QSP) models to apply the GSA to a complex model. In the simulations, covariate and random variables were generated to simulate the outcomes using the models. Ratios of variance explained by each factor (each covariate and random effect) over the overall variance of the outcome were used as sensitivity indices. The sensitivity indices were consistent with the effect size of covariate. The sensitivity indices identified the importance of creatinine clearance on the pharmacokinetic exposure for a renally-excreted drug. These sensitivity indices could be applied to plasma concentrations over time (repeated measurable outcomes over time) as interested outcomes. Using the GSA, each contribution of all of the covariate effects could be efficiently identified even in the complex QSP model. Variance-based GSA can provide insight when considering the importance of covariate effects by simultaneously and quantitatively assessing all covariate and random effects on interested outcomes in pharmacometrics.

Quantitative systems pharmacology model of thrombopoiesis and platelet life-cycle, and its application to thrombocytopenia based on chronic liver disease

Platelets are produced by hematopoietic stem cells via megakaryocytes in the bone marrow and play a critical role in hemostasis. The aim of this study was to develop a new platelet model based on the thrombopoiesis and platelet life-cycle by a quantitative systems pharmacology modeling approach, which could describe changes in platelet count profiles in platelet-related diseases and drug intervention. The proposed platelet model consists of 44 components. The model was applied to thrombopoiesis of a thrombopoietin receptor agonist, lusutrombopag. It could well describe the observed platelet count profiles after administration of lusutrombopag for both healthy subjects and patients with chronic liver disease and thrombocytopenia. This model should be useful for understanding the disease progression of platelet-related conditions, such as thrombocytopenia and for predicting platelet count profiles in various disease situations related to platelets and drug administration in drug development.

The Thrombopoietin Receptor Agonist Lusutrombopag Is Effective for Patients with Chronic Liver Disease and Impaired Renal Function

BACKGROUND

The thrombopoietin (TPO) receptor agonist lusutrombopag was developed to treat thrombocytopenia in chronic liver disease (CLD). However, its effectiveness remains unclear. The purpose of this study was to assess the efficacy of lusutrombopag and identify predictors associated with increase in platelet count.

METHODS

Eighty CLD patients with thrombocytopenia were enrolled. The primary endpoint was a satisfactory increase in platelets (greater than 1.0 × 10⁴/μL from baseline) in the absence of platelet transfusion. The secondary endpoints were response rate (an increase of greater than 1.0 × 10⁴/μL from baseline), independent predictors of increase in platelets, and the superiority of lusutrombopag over platelet transfusion.

RESULTS

The primary endpoint was achieved in 93.8% (75 of 80) patients. The response rate was 96.2% (77 of 80). Renal function parameters (blood urea nitrogen, creatinine, eGFR) were significantly negatively associated with platelet count (p = 0.033, 0.049, and 0.0014, respectively) and were identified as independent predictors by multiple regression analysis (p = 0.049, 0.0023, and 0.0016, respectively). The median increase in platelet count was significantly higher after lusutrombopag than after platelet transfusion (41,000 vs. 12,000/μL, p = 0.015).

CONCLUSION

Lusutrombopag was more effective than platelet transfusion for CLD patients, and renal function independently predicted increase in platelet count. Renal function parameters were significantly associated with platelet count.

Pharmacokinetic/Pharmacodynamic Modelling and Simulation of Lusutrombopag, a Novel Thrombopoietin Receptor Agonist, for the Treatment of Thrombocytopenia in Patients with Chronic Liver Disease Undergoing Invasive Procedures

BACKGROUND

Patients with thrombocytopenia associated with chronic liver disease (CLD) are at greater risk of bleeding during invasive procedures. This study characterized the pharmacokinetic/pharmacodynamic (PK/PD) profile of lusutrombopag, a novel thrombopoietin-receptor agonist, using modelling and simulation, and evaluated the appropriate dose regimen for treatment of thrombocytopenia in CLD patients undergoing invasive procedures.

METHODS

A population PK/PD model was developed using plasma lusutrombopag concentrations from 78 healthy subjects and 349 CLD patients, as well as platelet counts from 347 of these 349 patients. Covariates were explored from subject characteristics. Monte-Carlo simulations were performed to assess a dose response for efficacy (platelet counts ≥ 50,000/μL) and a risk for platelet overshooting (platelet counts > 200,000/μL).

RESULTS

Visual predictive checks indicated the developed models described the PK/PD profile of lusutrombopag well. In the simulations, without stopping criteria, lusutrombopag 3 mg once daily for 7 days before scheduled invasive procedures provided effective platelet response (85.2% probability for efficacy). The probability of platelet overshooting was 1.2%, indicating that platelet monitoring is not necessary. Although body weight was an influential covariate on the pharmacokinetics of lusutrombopag, individually estimated peak platelet counts overlapped among the body weight groups, suggesting no clinically significant effect on body weight.

CONCLUSION

The modelling and simulation support lusutrombopag 3 mg once daily for 7 days without platelet monitoring.

Evaluation of drug-drug interaction of lusutrombopag, a thrombopoietin receptor agonist, via metabolic enzymes and transporters

Purpose

Drug-drug interaction (DDI) potentials of lusutrombopag, a thrombopoietin receptor agonist, on the activity of cytochrome P450 (CYP) 3A and of cyclosporine, which inhibits P-glycoprotein and breast cancer resistance protein, on lusutrombopag pharmacokinetics were assessed via clinical studies and physiologically based pharmacokinetic (PBPK) modeling.

Methods

The effect of lusutrombopag on midazolam (a CYP3A probe substrate) pharmacokinetics was assessed in 15 healthy subjects receiving a single midazolam 5-mg dose with or without coadministration of lusutrombopag 0.75 mg for 6 days (first dose: 1.5-mg dose). The effect of cyclosporine on lusutrombopag pharmacokinetics was assessed in 16 healthy subjects receiving a single lusutrombopag 3-mg dose with or without a single cyclosporine 400- to 600-mg dose. PBPK modeling was employed to extrapolate the effect of lusutrombopag at the clinical dose (3 mg once daily) on midazolam pharmacokinetics.

Results

In the clinical study, mean ratios (90% confidence intervals [CIs]) of with/without lusutrombopag for maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of midazolam were 1.01 (0.908–1.13) and 1.04 (0.967–1.11), respectively, indicating no effect of lusutrombopag on midazolam pharmacokinetics. PBPK modeling suggested no effect of lusutrombopag at the clinical dose on midazolam pharmacokinetics. Mean ratios (90% CIs) of with/without cyclosporine for lusutrombopag C_max and AUC were 1.18 (1.11–1.24) and 1.19 (1.13–1.25), respectively, indicating a slight increase in lusutrombopag exposure.

Conclusions

In consideration with in vitro data, the in vivo and in silico results suggested no clinically significant DDI potential of lusutrombopag with other medical products via metabolic enzymes and transporters.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02960-7) contains supplementary material, which is available to authorized users.

Lusutrombopag: A Review in Thrombocytopenia in Patients with Chronic Liver Disease Prior to a Scheduled Procedure

Lusutrombopag (Mulpleta^®), an orally bioavailable, small molecule thrombopoietin receptor agonist, is approved for the treatment of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure. In placebo-controlled phase 3 clinical trials, lusutrombopag significantly increased the proportion of patients who did not require a platelet transfusion prior to the procedure or rescue therapy for bleeding up to 7 days after the scheduled procedure. Lusutrombopag also significantly increased the proportion of patients who were responders (i.e. had a platelet count ≥ 50 × 10⁹/L and an increase of ≥ 20 × 10⁹/L from baseline) compared with placebo. Lusutrombopag is well tolerated, with headache being the most common adverse reaction in lusutrombopag recipients in clinical trials. Thus, lusutrombopag represents a promising emerging therapeutic option for the treatment of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure.

Lusutrombopag for the Treatment of Thrombocytopenia in Patients With Chronic Liver Disease Undergoing Invasive Procedures (L-PLUS 2)

Thrombocytopenia may be associated with increased bleeding risk impacting timing and outcome of invasive procedures in patients with chronic liver disease (CLD). Lusutrombopag, a small-molecule, thrombopoietin (TPO) receptor agonist, was evaluated as a treatment to raise platelet counts (PCs) in patients with thrombocytopenia and CLD undergoing invasive procedures. L-PLUS 2 was a global, phase 3, randomized, double-blind, placebo-controlled study. Adults with CLD and baseline PCs < 50 × 10⁹ /L were randomized to receive once-daily lusutrombopag 3 mg or placebo ≤ 7 days before an invasive procedure scheduled 2-7 days after the last dose. The primary endpoint was avoidance of preprocedure platelet transfusion and avoidance of rescue therapy for bleeding. A key secondary endpoint was number of days PCs were ≥ 50 × 10⁹ /L throughout the study. Safety analysis was performed on patients who received at least one dose of study drug. This study occurred between June 15, 2015, and April 19, 2017, with a total of 215 randomized patients (lusutrombopag, 108; placebo, 107); 64.8% (70/108) of patients in the lusutrombopag group versus 29.0% (31/107) in the placebo group met the primary endpoint (P < 0.0001; difference of proportion 95% confidence interval [CI], 36.7 [24.9, 48.5]). The median duration of PCs ≥ 50 × 10⁹ /L was 19.2 days with lusutrombopag (without platelet transfusion) compared with 0.0 in the placebo group (with platelet transfusion) (P = 0.0001). Most adverse events were mild or moderate in severity, and rates were similar in the lusutrombopag and placebo groups (47.7% and 48.6%, respectively). Conclusion: Lusutrombopag was superior to placebo for reducing the need for platelet transfusions and achieved durable PC response in patients with thrombocytopenia and CLD undergoing invasive procedures, with a safety profile similar to placebo.

Effects of Food and Calcium Carbonate on the Pharmacokinetics of Lusutrombopag, a Novel Thrombopoietin Receptor Agonist

PURPOSE

Lusutrombopag is a novel, orally active thrombopoietin receptor agonist. This report describes 3 studies aimed at assessing the effects of food and calcium carbonate on the pharmacokinetic parameters of lusutrombopag in healthy subjects.

METHODS

Three single-dose, open-label crossover studies were conducted. In study 1, eighteen healthy subjects were administered a single 2-mg dose of lusutrombopag as a single tablet in the fasted or fed state or as a 2-mg solution in the fasted state. In study 2, fifteen healthy subjects were administered a single 0.75-mg dose of lusutrombopag as three 0.25-mg tablets in the fasted or fed state, or in the fasted state with coadministration of 4000-mg calcium carbonate. In study 3, fifteen healthy subjects were administered 4-mg lusutrombopag as a single tablet in the fasted or fed state. Pharmacokinetic parameters were estimated from plasma lusutrombopag concentrations.

FINDINGS

Mean fed versus fasted state ratios (90% CIs) of C_max and AUC_0-∞, respectively, were: 0.904 (0.864-0.945) and 0.920 (0.886-0.956) (study 1); 0.972 (0.864-1.09) and 1.02 (0.945-1.11) (study 2); and 0.917 (0.842-0.999) and 0.908 (0.855-0.964) (study 3). The respective ratios for calcium carbonate versus no calcium carbonate (fasted state) were 1.08 (0.959-1.21) and 0.989 (0.913-1.07) (study 2). Lusutrombopag exposure remained unaffected, except for a slight decrease in exposure with food. Lusutrombopag exposure did not change with the coadministration of calcium carbonate. These findings suggest that there was no clinically significant effect of food or calcium carbonate on the bioavailability of lusutrombopag. Each treatment regimen was well tolerated.

IMPLICATIONS

According to the present findings, no specific restrictions are required for lusutrombopag administration with regard to meals (including those with dairy products), mineral supplements, or coadministration of antacids.

CLINICAL TRIAL REGISTRATION

JapicCTI-No.: JapicCTI-194690, JapicCTI-194689. ClinicalTrials.gov identifier: NCT03897413.

New Small Molecule Drugs for Thrombocytopenia: Chemical, Pharmacological, and Therapeutic Use Considerations

This review provides details about three small molecules that were recently approved by the FDA for the treatment of thrombocytopenia. The new treatments include lusutrombopag, avatrombopag, and fostamatinib. The first two drugs are orally active thrombopoietin receptor (TPO-R) agonists which are FDA-approved for the treatment of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure. Fostamatinib is orally active prodrug that, after activation, becomes spleen tyrosine kinase (SYK) inhibitor. Fostamatinib is currently used to treat chronic and refractory immune thrombocytopenia in patients who have had insufficient response to previous treatment. Chemical structures, available dosage forms, recommended dosing, pharmacokinetics, results of toxicity studies in animals, most frequent adverse effects, significant outcomes of the corresponding clinical trials, and their use in specific patient populations are thoroughly described. Described also is a comparative summary of the different aspects of five currently available therapies targeting TPO-R or SYK for the treatment of thrombocytopenia.

Efficacy and safety of repeated use of lusutrombopag prior to radiofrequency ablation in patients with recurrent hepatocellular carcinoma and thrombocytopenia

AIMS

Thrombocytopenia is often associated with chronic liver disease. Lusutrombopag is a small molecule thrombopoietin receptor agonist designed to temporarily increase the platelet count in patients with chronic liver disease for whom elective invasive procedures are planned. In the present study, the efficacy and safety of repeated use of lusutrombopag prior to radiofrequency ablation (RFA) for recurrent hepatocellular carcinoma were examined.

METHODS

Eight patients with hepatocellular carcinoma who had a platelet count <50 000/μL prior to both initial and repeat RFA at the time of recurrence received lusutrombopag (3 mg/day) orally for 7 days between March 2016 and August 2018. The following were compared: the effect of lusutrombopag to increase the platelet count as determined by the platelet count after the initial and repeated use of lusutrombopag, the rate of avoiding platelet transfusion, and the presence of any complications.

RESULTS

The platelet count increased to 103 100 ± 22 800/μL 14 days after the first treatment and to 110 700 ± 17 800/μL 14 days after the repeated use. None of the patients required platelet transfusion. None of the patients developed clinical symptoms such as thrombosis, fever, rash, portal vein thrombosis, bleeding, or any other serious adverse events.

CONCLUSIONS

Repeated use of lusutrombopag increased the platelet count. It did not cause any serious adverse events and led to avoidance of platelet transfusion. Radiofrequency ablation was carried out safely in all patients. Future studies with more cases of repeated use are needed to examine the long-term efficacy and safety of lusutrombopag.

Romiplostim in adult patients with newly diagnosed or persistent immune thrombocytopenia (ITP) for up to 1 year and in those with chronic ITP for more than 1 year: a subgroup analysis of integrated data from completed romiplostim studies

The thrombopoietin receptor agonist romiplostim is approved for second-line use in chronic immune thrombocytopenia (ITP), but its effects in patients with ITP for ≤1 year are not well characterized. This analysis of pooled data from 9 studies included patients with ITP for ≤1 year (n = 311) or >1 year (n = 726) who failed first-line treatments and received romiplostim, placebo or standard of care. In subgroup analysis by ITP duration, patient incidences for platelet response at ≥75% of measurements were higher for romiplostim [ITP ≤1 year: 74% (204/277); ITP >1 year: 71% (450/634)] than for placebo/standard of care [ITP ≤1 year: 18% (6/34); ITP >1 year: 9% (8/92)]. Of patients with ≥9 months on study, 16% with ITP ≤1 year and 6% with ITP >1 year discontinued romiplostim and maintained platelet counts ≥50 × 109 /l for ≥6 months without ITP treatment (treatment-free remission). Independent of ITP duration, rates of serious adverse events and bleeding were lower with romiplostim than placebo/standard of care and thrombotic events occurred at similar rates. In this analysis, romiplostim and placebo/standard of care had similar safety profiles and romiplostim increased platelet counts in patients with either ITP ≤1 year or ITP >1 year, with more treatment-free remission in those with ITP ≤1 year.

A randomized controlled trial of lusutrombopag in Japanese patients with chronic liver disease undergoing radiofrequency ablation

BACKGROUND

Thrombocytopenia represents an obstacle for invasive procedures in chronic liver disease (CLD) patients. We aimed to estimate the appropriate dose and evaluate the efficacy and safety of lusutrombopag for the treatment of thrombocytopenia before percutaneous liver radiofrequency ablation (RFA) for primary hepatic cancer in patients with CLD.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled study conducted in Japan, 61 CLD patients with platelet count < 50 × 10³/µL at screening were randomized to placebo or lusutrombopag 2, 3, or 4 mg once daily for 7 days, followed by a 28-day post-treatment assessment period. The primary efficacy endpoint was the proportion of patients who did not require platelet transfusion before RFA. The pre-specified key secondary efficacy endpoint was the proportion of responders. Adverse events (AEs) and thrombosis-related AEs were evaluated.

RESULTS

The proportion of patients who did not require platelet transfusion before RFA and that of responders were significantly higher (p < 0.01) in the 2-mg (80.0, 66.7%), 3-mg (81.3, 68.8%), and 4-mg groups (93.3, 80.0%) compared with the placebo group (20.0, 6.7%) and showed a dose-dependent effect. The incidence of AEs was 97.8 and 100% in the lusutrombopag (all groups) and placebo groups, respectively; no dose-related increase was observed. Four patients experienced thrombosis-related events (one each in the placebo and 2-mg groups, and two in the 4-mg group). A total of 16 (18%) adverse drug reactions occurred in the safety analysis set.

CONCLUSIONS

Lusutrombopag 3 mg once daily for 7 days was effective without raising concerns about excessive increases in platelet count.

CLINICAL TRIAL REGISTRATION

The study is registered at JapicCTI-121944.

Relationship between response to lusutrombopag and splenic volume

AIM

To assess the correlation between the efficacy of lusutrombopag and clinical characteristics in patients with chronic liver disease.

METHODS

In this retrospective, multicenter study, which conducted at four locations in Japan, 50 thrombocytopenic patients with chronic liver disease were enrolled. All patients received oral lusutrombopag (3.0 mg/d for 7 d) for chronic liver disease. We assessed the increase in platelet count after the trial drug administration. A treatment response was defined as a platelet count ≥ 5 × 104/μL and an increased platelet count ≥ 2 × 104/μL from baseline after drug administration. We evaluated the response to lusutrombopag compared to baseline clinical characteristics in patients with chronic liver disease.

RESULTS

The numbers of responders and non-responders were 40 (80.0%) and 10 (20.0%), respectively. The patients were divided into a responder and non-responder group, and we added factors that may correspond to successful treatment with lusutrombopag. Splenic volume and body weight were lower in the responder group than in the non-responder group. White blood cell count and hemoglobin level were higher in responders compared with non-responders. Using a logistic regression model to assess the relationship between response to lusutrombopag and clinical characteristics, multivariate analysis confirmed that splenic volume was an independent factor that predicted the response of platelet counts (P = 0.025; odds ratio = 11.2; 95% confidence interval: 1.354-103.0). Splenic volume negatively correlated to changes in platelet count (r = -0.524, P = 0.001).

CONCLUSION

Splenic volume influences the change in platelet counts after administration of lusutrombopag in patients with chronic liver disease.

Two cases of liver cirrhosis treated with lusutrombopag before partial splenic embolization

Lusutrombopag, a small molecule thrombopoietin receptor agonist, has been approved for the treatment of chronic liver disease-associated thrombocytopenia due to hypersplenism in patients scheduled to undergo elective invasive procedures in Japan. We performed partial splenic embolization (PSE) after administration of lusutrombopag in two patients with thrombocytopenia due to cirrhosis.　Case 1 involved a 50-year-old man who developed cirrhosis due to hepatitis B virus (HBV) infection and alcohol consumption. Case 2 involved a 30-year-old woman who developed cirrhosis due to HBV infection only. Lusutrombopag administration led to an increase in platelet count in both patients, and PSE was performed safely. However, in Case 2, the patient developed disseminated intravascular coagulation. Further study with a larger population is required to investigate the indications for and risks of the use of lusutrombopag.