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

Lusutrombopag as a Repurposing Drug in Combination with Aminoglycosides against Vancomycin-Resistant Enterococcus

Due to the widespread abuse of antibiotics, drug resistance in Enterococcus has been increasing. However, the speed of antibiotic discovery cannot keep pace with the acquisition of bacterial resistance. Thus, drug repurposing is a proposed strategy to solve the crises. Lusutrombopag (LP) has been approved as a thrombopoietin receptor agonist by the Food and Drug Administration. This study demonstrated that LP exhibited significant antimicrobial activities against vancomycin-resistant Enterococcus in vitro with rare resistance occurrence. Further, LP combined with tobramycin exhibited synergistic antimicrobial effects in vitro and in vivo against Enterococcus. No in vitro or in vivo detectable toxicity was observed when using LP. Mechanism studies indicated that the disrupted proton motive force may account for LP's antimicrobial activity. In summary, these results demonstrate that LP has the previously undocumented potential to serve as an antibacterial agent against refractory infections caused by Enterococcus.

Identification of thrombopoiesis inducer based on a hybrid deep neural network model

Thrombocytopenia is a common haematological problem worldwide. Currently, there are no relatively safe and effective agents for the treatment of thrombocytopenia. To address this challenge, we propose a computational method that enables the discovery of novel drug candidates with haematopoietic activities. Based on different types of molecular representations, three deep learning (DL) algorithms, namely recurrent neural networks (RNNs), deep neural networks (DNNs), and hybrid neural networks (RNNs+DNNs), were used to develop classification models to distinguish between active and inactive compounds. The evaluation results illustrated that the hybrid DL model exhibited the best prediction performance, with an accuracy of 97.8 % and Matthews correlation coefficient of 0.958 on the test dataset. Subsequently, we performed drug discovery screening based on the hybrid DL model and identified a compound from the FDA-approved drug library that was structurally divergent from conventional drugs and showed a potential therapeutic action against thrombocytopenia. The novel drug candidate wedelolactone significantly promoted megakaryocyte differentiation in vitro and increased platelet levels and megakaryocyte differentiation in irradiated mice with no systemic toxicity. Overall, our work demonstrates how artificial intelligence can be used to discover novel drugs against thrombocytopenia.

Caulis Polygoni Multiflori Accelerates Megakaryopoiesis and Thrombopoiesis via Activating PI3K/Akt and MEK/ERK Signaling Pathways

Thrombocytopenia is one of the most common complications of cancer therapy. Until now, there are still no satisfactory medications to treat chemotherapy and radiation-induced thrombocytopenia (CIT and RIT, respectively). Caulis Polygoni Multiflori (CPM), one of the most commonly used Chinese herbs, has been well documented to nourish blood for tranquilizing the mind and treating anemia, suggesting its beneficial effect on hematopoiesis. However, it is unknown whether CPM can accelerate megakaryopoiesis and thrombopoiesis. Here, we employ a UHPLC Q–Exactive HF-X mass spectrometer (UHPLC QE HF-X MS) to identify 11 ingredients in CPM. Then, in vitro experiments showed that CPM significantly increased megakaryocyte (MK) differentiation and maturation but did not affect apoptosis and lactate dehydrogenase (LDH) release of K562 and Meg-01 cells. More importantly, animal experiments verified that CPM treatment markedly accelerated platelet recovery, megakaryopoiesis and thrombopoiesis in RIT mice without hepatic and renal toxicities in vivo. Finally, RNA-sequencing (RNA-seq) and western blot were used to determine that CPM increased the expression of proteins related to PI3K/Akt and MEK/ERK (MAPK) signaling pathways. On the contrary, blocking PI3K/Akt and MEK/ERK signaling pathways with their specific inhibitors suppressed MK differentiation induced by CPM. In conclusion, for the first time, our study demonstrates that CPM may be a promised thrombopoietic agent and provide an experimental basis for expanding clinical use.

Recent Advances in Nanomaterials for Diagnosis, Treatments, and Neurorestoration in Ischemic Stroke

Stroke is a major public health issue, corresponding to the second cause of mortality and the first cause of severe disability. Ischemic stroke is the most common type of stroke, accounting for 87% of all strokes, where early detection and clinical intervention are well known to decrease its morbidity and mortality. However, the diagnosis of ischemic stroke has been limited to the late stages, and its therapeutic window is too narrow to provide rational and effective treatment. In addition, clinical thrombolytics suffer from a short half-life, inactivation, allergic reactions, and non-specific tissue targeting. Another problem is the limited ability of current neuroprotective agents to promote recovery of the ischemic brain tissue after stroke, which contributes to the progressive and irreversible nature of ischemic stroke and also the severity of the outcome. Fortunately, because of biomaterials’ inherent biochemical and biophysical properties, including biocompatibility, biodegradability, renewability, nontoxicity, long blood circulation time, and targeting ability. Utilization of them has been pursued as an innovative and promising strategy to tackle these challenges. In this review, special emphasis will be placed on the recent advances in the study of nanomaterials for the diagnosis and therapy of ischemic stroke. Meanwhile, nanomaterials provide much promise for neural tissue salvage and regeneration in brain ischemia, which is also highlighted.

Small molecules as modulators of regulated cell death against ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury contributes to disability and mortality worldwide. Due to the complicated mechanisms and lack of proper therapeutic targets, few interventions are available that specifically target the pathogenesis of IR injury. Regulated cell death (RCD) of endothelial and parenchymal cells is recognized as the promising intervening target. Recent advances in IR injury suggest that small molecules exhibit beneficial effects on various RCD against IR injury, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, and parthanatos. Here, we describe the mechanisms behind these novel promising therapeutic targets and explain the machinery powering the small molecules. These small molecules exert protection by targeting endothelial or parenchymal cells to alleviate IR injury. Therapies of the ideal combination of small molecules targeting multiple cell types have shown potent synergetic therapeutic effects, laying the foundation for novel strategies to attenuate IR injury.

Evaluating fostamatinib disodium as a treatment option for immune thrombocytopenia in adult patients

INTRODUCTION

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by increased platelet destruction and decreased platelet production, leading to thrombocytopenia with or without bleeding manifestations. The majority of patients experiencing treatment need will eventually need secondary treatment following first line therapy with steroids. In 2018, the oral spleen tyrosine kinase inhibitor fostamatinib received US Food and Drug Administration approval for ITP patients with an insufficient response to a previous treatment.

AREAS COVERED

This review outlines pharmacological characteristics of fostamatinib and provides an overview of its efficacy and safety results in phase II and III trials, followed by the expert opinion of the authors.

EXPERT OPINION

Increasing knowledge on the role of different players and mechanisms in the pathophysiology of autoimmune disorders in general and of ITP in particular, has led to the development of several new treatment options, as illustrated by the introduction of fostamatinib in the treatment of ITP. However, lacking direct comparison with other recent treatment options (in particular thrombopoietin receptor agonists), its use should be evaluated critically taking into account the unique toxicity and potential drug-drug interaction profile.

Association between basal platelet count and all-cause mortality in critically ill patients with acute respiratory failure: a secondary analysis from the eICU collaborative research database

BACKGROUND

Evidence regarding the correlation between platelet count and all-cause mortality in critically ill patients with acute respiratory failure (ARF) is limited. Therefore, the aim of the study was to evaluate whether platelet count was associated with all-cause mortality in critical patients with ARF by using the electronic intensive care unit (eICU) Collaborative Research Database (eICU-CRD).

METHODS

In this retrospective multicenter cohort study, the data of 26961 patients with ARF hospitalized in ICUs between 2014 and 2015 were collected. The independent variable was log2 basal platelet count, and the dependent variables were all-cause in-hospital and ICU mortality. Covariates including demographic data, Acute Physiology and Chronic Health Evaluation (APACHE) IV score, supportive treatment, and comorbidities were collected.

RESULTS

In the fully adjusted model, log2 basal platelet count was negatively associated with all-cause mortality both in hospital [RR: 0.87, 95% CI: 0.84-0.91] and in ICU [RR: 0.87, 95% CI: 0.83-0.92]. A non-linear relationship between log2 basal platelet count and all-cause in-hospital and ICU mortality was identified by the nonlinearity test. The inflection points we got were 6.83 and 6.86 respectively (after inverse log2 logarithmic conversion, the platelet counts were 114×10⁹/L and 116×10⁹/L, respectively). On the right side of the inflection point, however, no association was observed between blood platelets and all-cause in-hospital (RR: 0.96, 95% CI: 0.88-1.03) and ICU mortality (RR: 0.97, 95% CI: 0.91-1.04).

CONCLUSIONS

For patients with ARF in ICU, platelet count was negatively associated with all-cause in-hospital and ICU mortality when the platelet count was less than 114×10⁹/L and 116×10⁹/L respectively, but when the platelet count was higher, we failed to observe a correlation between them. The safe ranges of platelet count for hospital stay and ICU stay were 78×10⁹/L-145×10⁹/L and 89×10⁹/L-147×10⁹/L respectively.

The structure, function, and clinical use of the thrombopoietin receptor agonist avatrombopag

Thrombopoietin regulates platelet production through activation of the thrombopoietin receptor (TPO-R). TPO-R agonists (TPO-RAs) are available to treat thrombocytopenia in chronic immune thrombocytopenia (ITP), chronic liver disease (CLD) patients who are undergoing a procedure, severe aplastic anemia (SAA), and hepatitis C virus (HCV) infection. There are four TPO-RAs approved in the US and Europe: romiplostim (ITP), eltrombopag (ITP, SAA, HCV), avatrombopag (ITP, CLD), and lusutrombopag (CLD). It is important to understand pharmacological characteristics of these agents when evaluating treatment options. Avatrombopag interacts with the transmembrane domain of the TPO-RA and does not compete with endogenous thrombopoietin for TPO-R binding. Structural differences between avatrombopag and other TPO-RAs may impart differential downstream effects on cell signaling pathways, potentially resulting in clinically relevant differences in outcome. Avatrombopag has a favorable pharmacological profile with similar exposure in Japanese, Chinese, or Caucasian patients and no drug-drug interactions, food interactions, or potential for chelation.

A Unified Transcriptional, Pharmacogenomic, and Gene Dependency Approach to Decipher the Biology, Diagnostic Markers, and Therapeutic Targets Associated with Prostate Cancer Metastasis

Simple Summary

This manuscript demonstrates how integrated bioinformatic and statistical reanalysis of publicly available genomic datasets can be utilized to identify molecular pathways and biomarkers that may be clinically relevant to metastatic prostate cancer (mPrCa) progression. The most notable observation is that the transition from primary prostate cancer to mPrCa is characterized by upregulation of processes associated with DNA replication, metastasis, and events regulated by the serine/threonine kinase PLK1. Moreover, our analysis also identified over-expressed genes that may be exploited for potential targeted therapeutics and minimally invasive diagnostics and monitoring of mPrCa. The primary data analyzed were two transcriptional datasets for tissues derived from normal prostate, primary prostate cancer, and mPrCa. Also incorporated in the analysis were the transcriptional, gene dependency, and drug response data for hundreds of cell lines, including those derived from prostate cancer tissues.

Abstract

Our understanding of metastatic prostate cancer (mPrCa) has dramatically advanced during the genomics era. Nonetheless, many aspects of the disease may still be uncovered through reanalysis of public datasets. We integrated the expression datasets for 209 PrCa tissues (metastasis, primary, normal) with expression, gene dependency (GD) (from CRISPR/cas9 screen), and drug viability data for hundreds of cancer lines (including PrCa). Comparative statistical and pathways analyses and functional annotations (available inhibitors, protein localization) revealed relevant pathways and potential (and previously reported) protein markers for minimally invasive mPrCa diagnostics. The transition from localized to mPrCa involved the upregulation of DNA replication, mitosis, and PLK1-mediated events. Genes highly upregulated in mPrCa and with very high average GD (~1) are potential therapeutic targets. We showed that fostamatinib (which can target PLK1 and other over-expressed serine/threonine kinases such as AURKA, MELK, NEK2, and TTK) is more active against cancer lines with more pronounced signatures of invasion (e.g., extracellular matrix organization/degradation). Furthermore, we identified surface-bound (e.g., ADAM15, CD276, ABCC5, CD36, NRP1, SCARB1) and likely secreted proteins (e.g., APLN, ANGPT2, CTHRC1, ADAM12) that are potential mPrCa diagnostic markers. Overall, we demonstrated that comprehensive analyses of public genomics data could reveal potentially clinically relevant information regarding mPrCa.

Engineered Bio-inspired Multifunctional Peptide- and Protein-based Therapeutic Biomolecules for Better Wound Care

Developing non-immunogenic therapeutic biomolecules for facilitating blood clotting followed by wound healing via therapeutic angiogenesis, still remains a formidable challenge. Excessive blood loss of accident victims and battalions cause a huge number of deaths worldwide. Patients with inherited bleeding disorders face acute complications during injury and post-surgery. Biologically-inspired peptide-based hemostat can act as a potential therapeutic for handling coagulopathy. Additionally, non-healing wounds for patients having ischemic diseases can cause severe clinical complications. Advancement in stabilized growth-factor-based proangiogenic therapy may offer effective possibilities for the treatment of ischemic pathology. This review will discuss nature-inspired biocompatible stabilized peptide- and protein-based molecular medicines to serve unmet medical challenges for handling traumatic coagulopathy and impaired wound healing.

Repurposing Pharmaceuticals Previously Approved by Regulatory Agencies to Medically Counter Injuries Arising Either Early or Late Following Radiation Exposure

The increasing risks of radiological or nuclear attacks or associated accidents have served to renew interest in developing radiation medical countermeasures. The development of prospective countermeasures and the subsequent gain of Food and Drug Administration (FDA) approval are invariably time consuming and expensive processes, especially in terms of generating essential human data. Due to the limited resources for drug development and the need for expedited drug approval, drug developers have turned, in part, to the strategy of repurposing agents for which safety and clinical data are already available. Approval of drugs that are already in clinical use for one indication and are being repurposed for another indication is inherently faster and more cost effective than for new agents that lack regulatory approval of any sort. There are four known growth factors which have been repurposed in the recent past as radiomitigators following the FDA Animal Rule: Neupogen, Neulasta, Leukine, and Nplate. These four drugs were in clinic for several decades for other indications and were repurposed. A large number of additional agents approved by various regulatory authorities for given indications are currently under investigation for dual use for acute radiation syndrome or for delayed pathological effects of acute radiation exposure. The process of drug repurposing, however, is not without its own set of challenges and limitations.

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.

Treatment of severe thrombocytopenia associated with systemic lupus erythematosus in pregnancy with eltrombopag: A case report and literature review

WHAT IS KNOWN AND OBJECTIVE

Severe thrombocytopenia associated with systemic lupus erythematosus (SLE) in pregnancy is infrequent. Its occurrence can lead to serious adverse pregnancy consequences and perinatal complications. The thrombopoietin (TPO) analogue eltrombopag has been successfully used in the treatment of autoimmune thrombocytopenia, but its safety and efficacy in severe thrombocytopenia during pregnancy remain unclear.

CASE SUMMARY

We report a 33-year-old woman with SLE at 29 + 3 weeks gestational age who developed severe thrombocytopenia with complaints of epistaxis, gum bleeding and haematuresis. Most conventional treatments including glucocorticoids, intravenous immunoglobulin (IVIG) and cyclosporine did not elevate her platelets, but eltrombopag worked well and her platelet count gradually recovered, allowing her to deliver a healthy baby at 36 + 3 weeks gestational age.

WHAT IS NEW AND CONCLUSION

This suggests that eltrombopag in combination with glucocorticoids has a good safety and efficacy profile in pregnant patients with SLE complicated by severe thrombocytopenia.

An evaluation of avatrombopag for the treatment of thrombocytopenia

Introduction: The thrombopoietin receptor agonists (TPO-RAs) are a class of drugs that have been FDA-approved for immune thrombocytopenia (ITP), periprocedural thrombocytopenia in patients with chronic liver disease (CLD), aplastic anemia, and thrombocytopenia associated with antiviral treatment of hepatitis C. Avatrombopag is a TPO-RA that is currently FDA-approved for ITP and periprocedural thrombocytopenia in patients with CLD and is currently undergoing evaluation for chemotherapy-induced thrombocytopenia (CIT) in an international phase III clinical trial. Areas covered: This paper summarizes the chemistry, pharmacodynamics, and pharmacokinetics of avatrombopag. In addition, the authors review the efficacy and safety of avatrombopag, covering clinical trials in patients with ITP and in patients with CLD scheduled to undergo a procedure. Expert opinion: Avatrombopag has demonstrated efficacy in patients with ITP. With its low side-effect burden, absence of hepatotoxicity, ease of use as an oral medication, and lack of food-drug interactions, avatrombopag is a favorable option for ITP, though there is a lack of long-term safety data. In periprocedural thrombocytopenia in patients with CLD, avatrombopag is comparable to lusutrombopag, another TPO-RA. Finally, the results of the study of avatrombopag in CIT are eagerly awaited, as there are no currently approved medications for this indication in the USA.

Thrombopoietin-receptor agonists in perioperative treatment of patients with chronic liver disease

Thrombocytopenia is a multifactorial disorder that is common in patients with chronic liver disease (CLD), leading to challenging perioperative planning. As thrombocytopenia in CLD is associated with thrombopoietin (TPO) deficiency, the use of TPO-receptor agonists (TPO-RAs) to increase platelet counts is a promising approach. This has led to the development of various TPO-RAs, including romiplostim, eltrombopag, avatrombopag, and lusutrombopag. Of these, only avatrombopag and lusutrombopag are approved by the United States Food and Drug Administration for the perioperative treatment of thrombocytopenia in patients with CLD. Platelet transfusion is commonly used for the clinical management of thrombocytopenia in patients with CLD undergoing invasive procedures. However, the limitations and possible risks of transfusion, including short duration of efficacy, development of antiplatelet antibodies, risk of infections and such complications as transfusion-related acute lung injury or circulatory overload, and possibility of refractoriness, limit its use. Moreover, there is no consensus among guidelines as to the platelet count at which transfusions are indicated. Results from studies using TPO-RAs perioperatively in patients with thrombocytopenia and CLD are promising and provide an alternative to platelet transfusions in the pre- and post-operative setting. These TPO-RAs are the subject of this review, with focus on their use in the perioperative setting in patients with thrombocytopenia, associated supporting clinical trials, efficacy and safety data, and their use with respect to platelet transfusions.