Chronic liver disease, thrombocytopenia and procedural bleeding risk; are novel thrombopoietin mimetics the solution?

Development of a machine learning-based model to predict hepatic inflammation in chronic hepatitis B patients with concurrent hepatic steatosis: a cohort study

Background

With increasingly prevalent coexistence of chronic hepatitis B (CHB) and hepatic steatosis (HS), simple, non-invasive diagnostic methods to accurately assess the severity of hepatic inflammation are needed. We aimed to build a machine learning (ML) based model to detect hepatic inflammation in patients with CHB and concurrent HS.

Methods

We conducted a multicenter, retrospective cohort study in China. Treatment-naive CHB patients with biopsy-proven HS between April 2004 and September 2022 were included. The optimal features for model development were selected by SHapley Additive explanations, and an ML algorithm with the best accuracy to diagnose moderate to severe hepatic inflammation (Scheuer's system ≥ G3) was determined and assessed by decision curve analysis (DCA) and calibration curve. This study is registered with ClinicalTrials.gov (NCT05766449).

Findings

From a pool of 1,787 treatment-naive patients with CHB and HS across eleven hospitals, 689 patients from nine of these hospitals were chosen for the development of the diagnostic model. The remaining two hospitals contributed to two independent external validation cohorts, comprising 509 patients in validation cohort 1 and 589 in validation cohort 2. Eleven features regarding inflammation, hepatic and metabolic functions were identified. The gradient boosting classifier (GBC) model showed the best performance in predicting moderate to severe hepatic inflammation, with an area under the receiver operating characteristic curve (AUROC) of 0.86 (95% CI 0.83-0.88) in the training cohort, and 0.89 (95% CI 0.86-0.92), 0.76 (95% CI 0.73-0.80) in the first and second external validation cohorts, respectively. A publicly accessible web tool was generated for the model.

Interpretation

Using simple parameters, the GBC model predicted hepatic inflammation in CHB patients with concurrent HS. It holds promise for guiding clinical management and improving patient outcomes.

Funding

This research was supported by the National Natural Science Foundation of China (No. 82170609, 81970545), Natural Science Foundation of Shandong Province (Major Project) (No. ZR2020KH006), Natural Science Foundation of Jiangsu Province (No.BK20231118), Tianjin Key Medical Discipline (Specialty), Construction Project, TJYXZDXK-059B, Tianjin Health Science and Technology Project key discipline special, TJWJ2022XK034, and Research project of Chinese traditional medicine and Chinese traditional medicine combined with Western medicine of Tianjin municipal health and Family Planning Commission (2021022).

Platelets and tyrosine kinase inhibitors: clinical features, mechanisms of action, and effects on physiology

Tyrosine kinase inhibitors (TKIs) have emerged as a promising class of target-directed, small molecule inhibitors used to treat hematologic malignancies, inflammatory diseases, and autoimmune disorders. Recently, TKIs have also gained interest as potential antiplatelet-directed therapeutics that could be leveraged to reduce pathologic thrombus formation and atherothrombotic complications, while minimally affecting platelet hemostatic function. This review provides a mechanistic overview and summarizes the known effects of tyrosine kinase inhibitors on platelet signaling and function, detailing prominent platelet signaling pathways downstream of the glycoprotein VI (GPVI) receptor, integrin αIIbβ3, and G protein-coupled receptors (GPCRs). This review focuses on mechanistic as well as clinically relevant and emerging TKIs targeting major families of tyrosine kinases including but not limited to Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (Syk), Src family kinases (SFKs), Janus kinases (JAK), and signal transducers and activators of transcription (STAT) and evaluates their effects on platelet aggregation and adhesion, granule secretion, receptor expression and activation, and protein phosphorylation events. In summation, this review highlights current advances and knowledge on the effects of select TKIs on platelet biology and furthers insight on signaling pathways that may represent novel druggable targets coupled to specific platelet functional responses.

The efficacy and safety of thrombopoietin receptor agonists in patients with chronic liver disease undergoing elective procedures: a systematic review and meta-analysis

Thrombopoietin receptor agonists (TPO-RAs) can mitigate preprocedural thrombocytopenia in patients with chronic liver disease (CLD) however their effects on procedural outcomes is unclear. In this meta-analysis, we aimed to better define the efficacy, thrombotic risk and bleeding mitigation associated with the use of preoperative TPO-RAs in patients with CLD. We performed a systematic review and meta-analysis of randomized placebo-controlled clinical trials to assess the use of preprocedural TPO-RAs in patients with CLD, searching MEDLINE, EMBASE and the Cochrane library database. Six publications comprising eight randomized trials (1229 patients; 717 received TPO-RAs, 512 received placebo) and three unique TPO-RAs were retrieved. The majority of the included procedures were endoscopic. TPO-RAs were significantly more likely to result in a preoperative platelet count greater than 50 x 109/L (72.1% vs 15.6%, RR 4.8, 95% CI 3.6-6.4 p < .00001. NNT 1.8) and reduced the incidence of platelet transfusions (22.5% vs 67.8%, RR 0.33, 95% CI 0.3-0.4 p < .00001. NNT 2.2). Total periprocedural bleeding was decreased in patients who received TPO-RAs (11.6% vs 15.6%, RR 0.64, 95% CI 0.5-0.9 p = .01. NNT 24.7) and there was no increase in the rate of thrombosis (2.2% vs 1.8% RR 1.25, 95% CI 0.6-2.9 p = .60. NNH 211.1). In patients with CLD the use of preprocedural TPO-RAs resulted in significant increased platelet counts, and decreased the incidence of platelet transfusions as compared to placebo. TPO use likewise decreased the incidence of total periprocedural bleeding without increasing the rate of thrombosis.

Assessing the periprocedural magnitude of platelet count change in response to lusutrombopag

BACKGROUND & AIMS

Despite limitations, platelet transfusion has been used to minimise bleeding risk in patients with thrombocytopaenia. Lusutrombopag is an oral, thrombopoietin receptor agonist approved for treatment of thrombocytopaenia associated with chronic liver disease in patients undergoing planned invasive procedures. This post-hoc analysis assessed the magnitude of platelet count change based on the integrated per-protocol population from 2 similar phase III multicentre, randomised, double-blind, placebo-controlled trials.

METHODS

Adults with chronic liver disease-induced thrombocytopaenia and platelet count <50 (× 109/L) received lusutrombopag 3 mg or placebo ≤7 days before invasive procedure scheduled 9-14 days after randomisation. Platelet transfusion was required per protocol if the platelet count remained <50 no more than 2 days before the planned invasive procedure. Post-hoc analysis included: proportion of patients with platelet count ≥50, ≥1.5-fold increase, and a doubling of platelet count; maximum and maximum change in platelet count; and platelet count time course.

RESULTS

Platelet count ≥50, a platelet count increase ≥1.5-fold, and at least a doubling in platelet count were achieved in 88.3%, 86.9%, and 52.6% of patients in the lusutrombopag group (n = 137) vs. 58.6%, 32.3%, and 6.0% of patients in the placebo group (n = 133), respectively. In the lusutrombopag group, median maximum platelet count across baseline platelet counts of <30, ≥30 to <40, and ≥40 was 46, 76, and 87, respectively. Median maximum change in platelet count by baseline platelet count was +24, +42, and +40, respectively. Patients who received lusutrombopag without platelet transfusion achieved a median platelet count ≥50 for 3 weeks.

CONCLUSIONS

Patients treated with lusutrombopag experienced a clinically relevant response in platelet count for a substantial duration of time.

LAY SUMMARY

Patients with low platelet counts caused by chronic liver disease may not receive planned invasive procedures or surgeries because of an increased risk of bleeding. Lusutrombopag has previously demonstrated efficacy in raising platelet counts and is approved to treat chronic liver disease patients with low platelet counts in advance of a planned surgery. Physicians need to understand more clearly what to expect in terms of platelet count change when using lusutrombopag; this integrated analysis provides data to help guide its clinical application.

Baseline thrombopoietin level is associated with platelet count improvement in thrombocytopenic chronic hepatitis C patients after successful direct-acting antiviral agent therapy

BACKGROUND

Thrombocytopenia can rapidly improve in chronic hepatitis C (CHC) patients receiving direct-acting antiviral agents (DAA). The role of baseline (BL) thrombopoietin (TPO) in this phenomenon is unclear.

METHODS

From June 2016 to February 2019, a total of 104 CHC patients receiving DAA, with a sustained virologic response and BL thrombocytopenia, at Dalin Tzu Chi Hospital, were enrolled in this retrospective study. Significant platelet count improvement and platelet count improvement ratio were analyzed for correlation with BL TPO.

RESULTS

This cohort included 40 men (38.5%). Seventy-two (69.2%) patients had advanced fibrosis. The platelet count [median (range)] increased from 110.5 (32-149) × 10³/µL at BL to 116.5 (40-196) and 118.0 (35-275) × 10³/µL at end of treatment (EOT) and 12 weeks after EOT (P12), respectively, (EOT vs. BL, P < 0.001; P12 vs. BL, P < 0.001). BL TPO was positively correlated with significant platelet count improvement (P < 0.001), platelet count improvement ratio at EOT (P = 0.004), and P12 (P < 0.001). The area under the receiver operating characteristic curve and optimal cutoffs (pg/ml) were 0.77 (95% confidence interval, 0.67-0.86) and 120, respectively, for significant platelet count improvement prediction. The sensitivity, specificity, and accuracy were 88.6%, 71.7%, and 78.8%, respectively.

CONCLUSIONS

BL TPO level might be a useful marker for predicting significant platelet count improvement in thrombocytopenic patients after successful DAA therapy.

Lusutrombopag Is Safe and Efficacious for Treatment of Thrombocytopenia in Patients With and Without Hepatocellular Carcinoma

BACKGROUND & AIMS

Patients with hepatocellular carcinoma (HCC) secondary to chronic liver disease often require invasive procedures but frequently have thrombocytopenia. Lusutrombopag is an agonist of the thrombopoietin receptor that activates platelet production.

METHODS

We performed an integrated analysis of data from 2 phase 3 trials (L-PLUS 1, Japan, October 2013 to May 2014, and L-PLUS 2, global, June 2015 to April 2017) that compared the efficacy and safety of lusutrombopag with placebo in patients with chronic liver disease, with and without HCC. Our analysis included patients with Eastern Cooperative Oncology Group grades of 0 or 1, Child-Pugh classes A or B, and a platelet count less than 50 × 10⁹/L who were scheduled to undergo invasive procedures in 9 to 14 days. Patients received lusutrombopag (3 mg) or placebo daily for 7 days or fewer before an invasive procedure. Imaging studies assessed treatment-emergent adverse events, including asymptomatic portal vein thrombosis. The primary end point was no requirement for platelet transfusion before the invasive procedure and rescue therapies for bleeding 7 days or fewer after the invasive procedure.

RESULTS

The per-protocol population included 270 patients (95 with HCC). A significantly higher proportion of patients with HCC who received lusutrombopag achieved the primary end point (68.0%) vs patients who received placebo (8.9%) (P < .0001); in patients without HCC, these proportions were 77.0% vs 21.6% (P < .0001). Lusutrombopag reduced the need for platelet transfusions, increased platelet counts for 3 weeks, and reduced the number of bleeding events in patients with and without HCC compared with placebo. Risk of thrombosis was similar to that of placebo.

CONCLUSIONS

Patients with and without HCC receiving lusutrombopag had a reduction in the number of platelet transfusions before invasive procedures compared with patients receiving placebo, with no increase in thrombosis or bleeding. L-PLUS 1: JapicCTI-132323; L-PLUS 2: ClinicalTrials.gov number no: NCT02389621.

Pharmacokinetics of Lusutrombopag, a Novel Thrombopoietin Receptor Agonist, in Rats by UPLC-MS/MS

Lusutrombopag is a second oral thrombopoietin (TPO) receptor agonist that selectively acts on human TPO receptors. In the study, UPLC-MS/MS was used to establish a selective and sensitive method to determine lusutrombopag with poziotinib as IS (internal standard) in rat plasma. Samples were prepared by precipitating protein with acetonitrile as a precipitant. Separation of lusutrombopag and poziotinib was performed on a CORTECS UPLC C18 column (2.1 ∗ 50 mm, 1.6 μm). The mobile phase (acetonitrile and water containing 0.1% formic acid) with gradient elution was set at a flow rate of 0.4 ml/min. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM) of m/z 592.97 ⟶ 491.02 for lusutrombopag and m/z for poziotinib (IS) 492.06 ⟶ 354.55. The linear calibration curve of the concentration range was 2–2000 ng/ml for lusutrombopag, with a lower limit of quantification (LLOQ) of 2 ng/ml. RSD of interday and intraday precision were both no more than 9.66% with the accuracy ranging from 105.82% to 108.27%. The extraction recovery of lusutrombopag was between 82.15% and 90.34%. The developed and validated method was perfectly used in the pharmacokinetic study of lusutrombopag after oral administration in rats.

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.