Ibrutinib-associated bleeding: pathogenesis, management and risk reduction strategies

Bleeding by Bruton Tyrosine Kinase-Inhibitors: Dependency on Drug Type and Disease

Bruton tyrosine kinase (Btk) is expressed in B-lymphocytes, myeloid cells and platelets, and Btk-inhibitors (BTKi) are used to treat patients with B-cell malignancies, developed against autoimmune diseases, have been proposed as novel antithrombotic drugs, and been tested in patients with severe COVID-19. However, mild bleeding is frequent in patients with B-cell malignancies treated with the irreversible BTKi ibrutinib and the recently approved 2nd generation BTKi acalabrutinib, zanubrutinib and tirabrutinib, and also in volunteers receiving in a phase-1 study the novel irreversible BTKi BI-705564. In contrast, no bleeding has been reported in clinical trials of other BTKi. These include the brain-penetrant irreversible tolebrutinib and evobrutinib (against multiple sclerosis), the irreversible branebrutinib, the reversible BMS-986142 and fenebrutinib (targeting rheumatoid arthritis and lupus erythematodes), and the reversible covalent rilzabrutinib (against pemphigus and immune thrombocytopenia). Remibrutinib, a novel highly selective covalent BTKi, is currently in clinical studies of autoimmune dermatological disorders. This review describes twelve BTKi approved or in clinical trials. By focusing on their pharmacological properties, targeted disease, bleeding side effects and actions on platelets it attempts to clarify the mechanisms underlying bleeding. Specific platelet function tests in blood might help to estimate the probability of bleeding of newly developed BTKi.

Dabigatran in ibrutinib-treated patients with atrial fibrillation and chronic lymphocytic leukemia: experience of three cases

Ibrutinib is the first clinically approved inhibitor of Bruton's tyrosine kinase, an essential enzyme for survival and proliferation of B cells by activating the B-cell receptor-signalling pathway. Ibrutinib has been shown to be highly effective in B-cell malignancies and is recommended in current international guidelines as a first-line and/or second-line treatment of chronic lymphocytic leukemia. The drug has a favorable tolerability and safety profile but the occurrence of specific side effects (e.g. atrial fibrillation, bleeding and hypertension). If atrial fibrillation is diagnosed, anticoagulant therapy may be required. Such patients receiving concomitant anticoagulation should be followed closely. DOAC is preferred over a VKA because of the lower risk of major bleeding events and because of the favorable stroke risk--benefit profile. Of all, Dabigatran offers the availability of an antidote and shows reduced potential for CYP3A4 interactions. We report the cases relating to three patients in concomitant therapy with Ibrutinib and Dabigatran.

Monogenic Immune Diseases Provide Insights Into the Mechanisms and Treatment of Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (GvHD) has become a leading cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HSCT) and can burden patients with devastating and lifelong health effects. Our understanding of the pathogenic mechanisms underlying chronic GvHD remains incomplete and this lack of understanding is reflected by lack of clear therapeutic approaches to steroid refractory disease. Observations predominantly from mouse models and human correlative studies currently support a three phase model for the initiation and development of chronic GvHD: 1) early inflammation and tissue damage triggers the innate immune system. This leads to inflammatory cytokine/chemokine patterns that recruit effector immune cell populations; 2) chronic inflammation causes the loss of central and peripheral tolerance mechanisms leading to emergence of pathogenic B and T cell populations that promote autoimmune and alloimmune reactions; 3) the dysregulated immunity causes altered macrophage polarization, aberrant tissue repair leading to scarring and end organ fibrosis. This model has led to the evaluation of many new therapies aimed at limiting inflammation, targeting dysregulated signaling pathways and restoring tolerance mechanisms. However, chronic GvHD is a multisystem disease with complex clinical phenotypes and it remains unclear as to which cluster of patients will respond best to specific therapeutic strategies. However, it is possible to gain novel insights from immune-related monogenic diseases. These diseases either share common clinical manifestations, replicate steps from the three phase chronic GvHD model or serve as surrogates for perfectly targeted drugs being investigated in chronic GvHD therapy. In this review, we will summarize the evidence from these monogenic immune related diseases that provide insight into pathogenic pathways in chronic GvHD, rationales for current therapies and novel directions for future drug discovery.

High-Risk Mantle Cell Lymphoma in the Era of Novel Agents

PURPOSE OF REVIEW

Mantle cell lymphoma (MCL) is a heterogenous disease with a variety of morphologic and genetic features, some of which are associated with high risk disease. Here we critically analyze the current state of the understanding of MCL's biology and its implications in therapy, with a focus on chemotherapy-free and targeted therapy regimens.

RECENT FINDINGS

Mantle cell lymphoma (MCL) is a rare subtype of non-Hodgkin's lymphoma, defined by a hallmark chromosomal translocation t(11;14) which leads to constitutive expression of cyclin D1. Recent discoveries in the biology of MCL have identified a number of factors, including TP53 mutations and complex karyotype, that lead to unresponsiveness to traditional chemoimmunotherapy and poor outcomes. Bruton tyrosine kinase inhibitors, BH3-mimetics and other novel agents thwart survival of the neoplastic B-cells in a manner independent of high-risk mutations and have shown promising activity in relapsed/refractory MCL. These therapies are being investigated in the frontline setting, while optimal responses to chemotherapy-free regimens, particularly in high-risk disease, might require combination approaches. High-risk MCL does not respond well to chemoimmunotherapy. Targeted agents are highly active in the relapsed refractory setting and show promise in high-risk disease. Novel approaches may soon replace the current standard of care in both relapsed and frontline settings.

Multifactorial Background for a Low Biological Response to Antiplatelet Agents Used in Stroke Prevention

Effective platelet inhibition is the main goal of the antiplatelet therapy recommended as a standard treatment in the secondary prevention of non-embolic ischemic stroke. Acetylsalicylic acid (aspirin) and clopidogrel are commonly used for this purpose worldwide. A low biological response to antiplatelet agents is a phenomenon that significantly reduces the therapeutic and protective properties of the therapy. The mechanisms leading to high on-treatment platelet reactivity are still unclear and remain multifactorial. The aim of the current review is to establish the background of resistance to antiplatelet agents commonly used in the secondary prevention of ischemic stroke and to explain the possible mechanisms. The most important factors influencing the incidence of a low biological response were demonstrated. The similarities and the differences in resistance to both drugs are emphasized, which may facilitate the selection of the appropriate antiplatelet agent in relation to specific clinical conditions and comorbidities. Despite the lack of indications for the routine assessment of platelet reactivity in stroke subjects, this should be performed in selected patients from the high-risk group. Increasing the detectability of low antiaggregant responders, in light of its negative impact on the prognosis and clinical outcomes, can contribute to a more individualized approach and modification of the antiplatelet therapy to maximize the therapeutic effect in the secondary prevention of stroke.

Steroid-refractory chronic graft-versus-host disease: treatment options and patient management

Chronic graft-versus-host disease (cGVHD) is one of the major causes of late mortality after allogenic hematopoietic stem cell transplantation. Moderate-to-severe cGVHD is associated with poor health-related quality of life and substantial disease burden. While corticosteroids with or without calcineurin inhibitors comprise the first-line treatment option, the prognosis for patients with steroid-refractory cGVHD (SR-cGVHD) remains poor. The mechanisms underlying steroid resistance are unclear, and there are no standard second-line treatment guidelines for patients with SR-cGVHD. In this review, we provide an overview on current treatment options of cGVHD and use a series of theoretical case studies to elucidate the rationale of choices of second- and third-line treatment options for patients with SR-cGVHD based on individual patient profiles.

Effects of Ibrutinib on biophysical parameters of platelet in patients with chronic lymphocytic leukaemia

Patients with chronic lymphocytic leukemia (CLL) treated with Ibrutinib often present hemorrhagic complications. Platelets dysfunction is well documented by aggregometry and flow cytometry, but the mechanisms by which Ibrutinib treatment influences the platelets status is yet to be evaluated. The aim of this study is to identify platelet membrane parameters in chronic lymphocytic leukemia (CLL) that could be altered by Ibrutinib administration. In this paper we propose a set of fluorescence measurements of the following parameters: membrane fluidity, resting membrane potential, and reactive oxygen species production of platelets suspensions obtained from CLL patients treated or not with Ibrutinib as markers for platelets status in this pathological situation. Platelets from CLL patients treated with Ibrutinib have higher membrane fluidity, lower resting membrane potential and higher level of reactive oxygen species production compared to the untreated CLL patients. These patients are also presenting higher membrane fluidity and lower resting membrane potential compared to healthy volunteers.

Inpatient Management of Mucocutaneous GVHD

Purpose of Review

Graft-versus-host disease (GVHD) is an immune mediated disorder affecting 30 - 70% of patients after allogeneic hematopoietic stem cell transplantation (alloHSCT), and is a major cause of morbidity and non-relapse mortality (NRM) [1]. Dermatologists play a critical role in acute and chronic GVHD, as skin involvement is common and often the earliest involved site of disease [2].

Recent Findings

GVHD shares clinical and histopathological features with a variety of other skin diseases, requiring thorough consideration of differential diagnoses in hematopoietic stem cell transplantation (HSCT) recipients with lesions suggestive of cutaneous GVHD. Treatment considerations for GVHD are influenced by factors such as disease classification, overall grading, organ involvement, associated symptoms, and immunological anti-tumor effect. Several treatments are available and may be indicated as monotherapy or adjuvant therapy to allow faster withdrawal or tapering of immunosuppression. While corticosteroids are often first line therapy, oral ruxolitinib has been recently approved for treatment of steroid-refractory aGHVD, and oral ibrutinib has been approved for steroid-refractory cGHVD.

Summary

This article provides current clinical, diagnostic, and therapeutic considerations relevant to the hospitalist for both acute and chronic mucocutaneous GVHD. Optimal inpatient management of these diseases requires an interdisciplinary team.

Novel antiplatelet strategies targeting GPVI, CLEC-2 and tyrosine kinases

Antiplatelet medications comprise the cornerstone of treatment for diseases that involve arterial thrombosis, including acute coronary syndromes (ACS), stroke and peripheral arterial disease. However, antiplatelet medications may cause bleeding and, furthermore, thrombotic events may still recur despite treatment. The interaction of collagen with GPVI receptors on the surface of platelets has been identified as one of the major players in the pathophysiology of arterial thrombosis that occurs following atherosclerotic plaque rupture. Promisingly, GPVI deficiency in humans appears to have a minimal impact on bleeding. These findings together suggest that targeting platelet GPVI may provide a novel treatment strategy that provides additional antithrombotic efficacy with minimal disruption of normal hemostasis compared to conventional antiplatelet medications. CLEC-2 is gaining interest as a therapeutic target for a variety of thrombo-inflammatory disorders including deep vein thrombosis (DVT) with treatment also predicted to cause minimal disruption to hemostasis. GPVI and CLEC-2 signal through Src, Syk and Tec family tyrosine kinases, providing additional strategies for inhibiting both receptors. In this review, we summarize the evidence regarding GPVI and CLEC-2 and strategies for inhibiting these receptors to inhibit platelet recruitment and activation in thrombotic diseases.

Effects of novel Btk and Syk inhibitors on platelet functions alone and in combination in vitro and in vivo

BACKGROUND

Inhibitors of tyrosine kinases downstream of the B-cell receptor, such as Bruton's tyrosine kinase (Btk) or Spleen tyrosine kinase (Syk), used alone or in combination are new therapeutic options in the treatment of B-cell malignancies. A challenge in the development of second-generation Btk inhibitors is to limit their side effects such as the increased bleeding risk. Considering the pivotal role of Syk in immunoreceptor tyrosine-based activation motif mediated platelet signaling, the impact of inhibiting this kinase on platelet functions is also worth analyzing.

OBJECTIVES

We investigated the effect of a novel Btk inhibitor, tirabrutinib, and a Syk inhibitor, entospletinib, alone and in combination on platelet signaling and functions in vitro and ex vivo.

METHODS

Platelet aggregation, secretion, and signaling responses as well as thrombus growth under flow were analyzed in the presence of the inhibitors alone or in combination in vitro, at clinically relevant doses, and ex vivo in patients treated with these inhibitors in the context of a phase I trial.

RESULTS

Although tirabrutinib alone had modest effects on platelet activation in vitro and ex vivo, entospletinib alone efficiently inhibited washed platelet aggregation in response to collagen. However, entospletinib weakly affected platelet activation in platelet-rich plasma, in whole blood and ex vivo. Importantly, the combination of tirabrutinib and entospletinib induced a significant decrease in platelet response to collagen in vitro and ex vivo correlating with mild bleedings reported in some of the treated patients.

CONCLUSION

These new results should contribute to improve the safety of these targeted therapies.

Dermatological Toxicities of Bruton's Tyrosine Kinase Inhibitors

The development of Bruton's tyrosine kinase (BTK) inhibitors represents a major breakthrough in the treatment of chronic lymphocytic leukemia and other B cell malignancies. The first-generation inhibitor ibrutinib works by covalent irreversible binding to BTK, a non-receptor tyrosine kinase of the TEC (transient erythroblastopenia of childhood) family that plays a critical role in the B-cell receptor signaling pathway. It also induces an 'off-target' inhibition of a range of other kinases including (but not limited to) epidermal growth factor receptor (EGFR), SRC, and other kinases of the TEC family (interleukin-2-inducible T-cell kinase [ITK], Tec, BMX). Dermatological toxicities are among the most common toxicities of ibrutinib, but remain of mild to moderate intensity in most cases and are readily manageable. Their incidence is highest during the first year of treatment and declines over time. In addition, it has been postulated that ibrutinib-related dermatologic adverse events are mediated by the direct binding to both BTK and other 'off-target' kinases. Bruising, ecchymoses, and petechiae represent the most characteristic dermatologic adverse events. Nail and hair changes are also common, as skin infections (opportunistic infections including herpes simplex and herpes zoster virus reactivations, and Staphylococcus aureus superinfection), folliculitis, and other types of rashes. Panniculitis, aphthous-like ulcerations with stomatitis, neutrophilic dermatosis, peripheral edema, and skin cracking can also occur. Next-generation BTK inhibitors, acalabrutinib and zanubrutinib, have been designed to optimize BTK inhibition and minimize off-target inhibition of alternative kinases (Tec, ITK, EGFR, SRC-family kinases). These drugs have been recently FDA-approved for relapsed or refractory mantle cell lymphoma. Although the overall incidence of their toxicities is expected to be more limited, acalubrutinib and zanubrutinib are associated with a range of dermatologic toxic effects that appear to be similar to those previously described with ibrutinib, including bruising and ecchymoses, panniculitis, human herpesvirus infections, cellulitis, and skin rash. In particular, both drugs induce skin bleeding events in more than 30% of patients treated. However, the available dermatological data are still rather limited and will have to be consolidated prospectively. This review article analyses the wide spectrum of dermatological toxicities that can be encountered with first- and second-generation BTK inhibitors. Finally, recommendations for appropriate treatment as well as a synthesis algorithm for management are also proposed.

Risk of Bleeding Associated With Ibrutinib in Patients With B-Cell Malignancies: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Ibrutinib is an oral covalent Bruton's tyrosine kinase inhibitor that has been approved for chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia and some other B-cell malignancies. Some studies have found an increased risk of bleeding with ibrutinib. Some studies, however, found no significant differences in the risk of major bleeding between patients treated with ibrutinib and those with other regimens. So, a systematic review and meta-analysis of randomized controlled trials (RCTs) were performed to estimate the risk of bleeding associated with ibrutinib in patients with B-cell malignancies. Methods: A systematic search of PUBMED, EMBASE, Central Register of Controlled Trials, and ClinicalTrials.gov was conducted from January 2000 to February 2020 to identify RCTs by comparing ibrutinib with other agents or placebo in B-cell malignancies. The RevMan software (version 5.3) was used to carry out this analysis, and the analyzed data were represented by risk ratios (RR) and 95% confidence intervals (CI). Results: There were 11 eligible RCTs (4,288 patients). All studies reported major bleeding, and seven studies reported overall bleeding (any-grade bleeding). Ibrutinib was associated with a significantly increased risk of bleeding (overall bleeding and major bleeding) in patients with B-cell malignancies [RR = 2.56, 95% CI 1.68-3.90, p < 0.0001 and RR = 2.08, 95% CI 1.36-3.16, p = 0.0006, respectively]. The bleeding (overall bleeding and major bleeding) risk in patients with CLL was more obvious [RR = 3.08, 95% CI 2.07-4.58, p < 0.00001 and RR = 2.46, 95% CI 1.37-4.41, p = 0.003, respectively]. There were no statistically significant differences for risk of bleeding between the subgroups based on dose and treatment setting. Conclusion: Ibrutinib was associated with a significantly higher risk of bleeding (both overall bleeding and major bleeding) in patients with B-cell malignancies, especially in CLL.

Incorporating acalabrutinib, a selective next-generation Bruton tyrosine kinase inhibitor, into clinical practice for the treatment of haematological malignancies

Greater understanding of the mechanisms involved in the disease progression of haematological malignancies has led to the introduction of novel targeted therapies with reduced toxicity compared with chemotherapy-based regimens, which has expanded the treatment options for patients with mantle cell lymphoma (MCL) and chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). Ibrutinib is a first-in-class Bruton tyrosine kinase (BTK) inhibitor indicated for the treatment of patients with CLL/SLL or relapsed/refractory MCL. However, next-generation BTK inhibitors have been developed with improved specificity and the potential to reduce the off-target toxicity observed with ibrutinib. Acalabrutinib is a highly selective, next-generation BTK inhibitor, which was granted accelerated approval by the US Food and Drug Administration in 2017 for the treatment of adult patients with MCL who have received at least one prior therapy. In November 2019, it was also granted approval for the treatment of adult patients with CLL/SLL on the basis of two phase 3 clinical trials. This review describes the current understanding of acalabrutinib according to clinical study data for the treatment of MCL and CLL/SLL and shares recommendations from our practice on how it should be used when treating patients in the clinic, including dosing, administration and management of adverse events.

A randomized phase 3 trial of zanubrutinib vs ibrutinib in symptomatic Waldenström macroglobulinemia: the ASPEN study

Bruton tyrosine kinase (BTK) inhibition is an effective treatment approach for patients with Waldenström macroglobulinemia (WM). The phase 3 ASPEN study compared the efficacy and safety of ibrutinib, a first-generation BTK inhibitor, with zanubrutinib, a novel highly selective BTK inhibitor, in patients with WM. Patients with MYD88L265P disease were randomly assigned 1:1 to treatment with ibrutinib or zanubrutinib. The primary end point was the proportion of patients achieving a complete response (CR) or a very good partial response (VGPR) by independent review. Key secondary end points included major response rate (MRR), progression-free survival (PFS), duration of response (DOR), disease burden, and safety. A total of 201 patients were randomized, and 199 received ≥1 dose of study treatment. No patient achieved a CR. Twenty-nine (28%) zanubrutinib patients and 19 (19%) ibrutinib patients achieved a VGPR, a nonstatistically significant difference (P = .09). MRRs were 77% and 78%, respectively. Median DOR and PFS were not reached; 84% and 85% of ibrutinib and zanubrutinib patients were progression free at 18 months. Atrial fibrillation, contusion, diarrhea, peripheral edema, hemorrhage, muscle spasms, and pneumonia, as well as adverse events leading to treatment discontinuation, were less common among zanubrutinib recipients. Incidence of neutropenia was higher with zanubrutinib, although grade ≥3 infection rates were similar in both arms (1.2 and 1.1 events per 100 person-months). These results demonstrate that zanubrutinib and ibrutinib are highly effective in the treatment of WM, but zanubrutinib treatment was associated with a trend toward better response quality and less toxicity, particularly cardiovascular toxicity.

The safety of available chemo-free treatments for mantle cell lymphoma

INTRODUCTION

Conventional treatment for mantle cell lymphoma (MCL) patients includes regimens combining rituximab with other cytotoxic drugs, followed or not by consolidation with autologous stem cell transplantation and rituximab maintenance. However, older, unfit, and relapsed/refractory patients are often ineligible for intense treatment. Currently, available new targeted treatment options seem to offer hope in this group of patients.

AREAS COVERED

This article reviews the safety profiles of new therapeutic chemotherapy-free options for MCL patients. Publications in English from 2010 through June 2020 were surveyed on the MEDLINE database for articles. Proceedings of the American Society of Hematology during the last 5 years were also included.

EXPERT OPINION

MCL is a clinically heterogenous disease predominantly affecting elderly patients. Its variable clinical course requires personalization and individualization of treatment to achieve optimal survival and acceptable safety profiles, especially in poor prognosis patients. Results of clinical trials performed in the past decade indicated that novel drugs used as a single agent or as part of a conventional chemotherapeutic treatment offer promise in minimalizing the relapse rate for MCL and may allow more effective and safer treatment options by reducing the risk of adverse events, especially cytopenias and infections.

Oral Bruton tyrosine kinase inhibitors block activation of the platelet Fc receptor CD32a (FcγRIIA): a new option in HIT?

Activation of the platelet Fc-receptor CD32a (FcγRIIA) is an early and crucial step in the pathogenesis of heparin-induced thrombocytopenia type II (HIT) that has not been therapeutically targeted. Downstream FcγRIIA Bruton tyrosine kinase (BTK) is activated; however, its role in Fc receptor-induced platelet activation is unknown. We explored the potential to prevent FcγRIIA-induced platelet activation by BTK inhibitors (BTKi's) approved (ibrutinib, acalabrutinib) or in clinical trials (zanubrutinib [BGB-3111] and tirabrutinib [ONO/GS-4059]) for B-cell malignancies, or in trials for autoimmune diseases (evobrutinib, fenebrutinib [GDC-0853]). We found that all BTKi's blocked platelet activation in blood after FcγRIIA stimulation by antibody-mediated cross-linking (inducing platelet aggregation and secretion) or anti-CD9 antibody (inducing platelet aggregation only). The concentrations that inhibit 50% (IC50) of FcγRIIA cross-linking-induced platelet aggregation were for the irreversible BTKi's ibrutinib 0.08 µM, zanubrutinib 0.11 µM, acalabrutinib 0.38 µM, tirabrutinib 0.42 µM, evobrutinib 1.13 µM, and for the reversible BTKi fenebrutinib 0.011 µM. IC50 values for ibrutinib and acalabrutinib were four- to fivefold lower than the drug plasma concentrations in patients treated for B-cell malignancies. The BTKi's also suppressed adenosine triphosphate secretion, P-selectin expression, and platelet-neutrophil complex formation after FcγRIIA cross-linking. Moreover, platelet aggregation in donor blood stimulated by sera from HIT patients was blocked by BTKi's. A single oral intake of ibrutinib (280 mg) was sufficient for a rapid and sustained suppression of platelet FcγRIIA activation. Platelet aggregation by adenosine 5'-diphosphate, arachidonic acid, or thrombin receptor-activating peptide was not inhibited. Thus, irreversible and reversible BTKi's potently inhibit platelet activation by FcγRIIA in blood. This new rationale deserves testing in patients with HIT.

Managing Patients at Risk of Medication Related Complications Requiring Dental Extractions in Primary Care

When undertaking dental extractions in modern dental practice, two of the complications that have the potential to cause most apprehension for clinicians are the risks of osteonecrosis of the jaws and uncontrollable haemorrhage. This is especially the case when treating older patients because of the increased likelihood of co-morbidities and accompanying polypharmacy which can predispose patients to these problems. Specific medications of concern to practitioners in relation to osteonecrosis risk are antiangiogenic and antiresorptive drugs. Patients taking dual antiplatelet therapy and direct oral anticoagulants require consideration in relation to bleeding risk. With these medications coming increasingly to the forefront over recent years, guidance has been developed by organisations such as the Scottish Dental Clinical Effectiveness Programme (SDCEP). Appropriate use of these guideline should ensure that patients felt to be at particular risk of these complications can frequently be safely managed in primary care. This article aims to provide advice on recognising patients at risk, and to discuss how to utilise key messages within published guidelines when making treatment decisions. The overall intent is to help primary care clinicians who are likely to encounter these patients more and more.

Drug interactions with Bruton's tyrosine kinase inhibitors: clinical implications and management

Bruton's tyrosine kinase (BTK) plays an essential role in B-cell development, differentiation and B-cell receptor (BCR) signaling. The use of Bruton's tyrosine kinase inhibitors (BTKi) in the treatment of lymphoid malignancies has dramatically increased, owing to both impressive efficacy and ease of administration. However, BTKi have a range of drug-drug and drug-food interactions, which may alter drug efficacy and/or increase toxicity. Healthcare professionals should be aware of the probability of drug interactions with BTKi and make recommendations accordingly. In this article, we discuss the relevant drug-drug and drug-food interactions associated with ibrutinib, acalabrutinib, and zanubrutinib, and provide clinical practice recommendations for managing these interactions based on the available literature.

Ibrutinib, but not zanubrutinib, induces platelet receptor shedding of GPIb-IX-V complex and integrin αIIbβ3 in mice and humans

The Bruton's tyrosine kinase (Btk) inhibitor ibrutinib has proven to be efficacious in the treatment of B-cell chronic lymphocytic leukemia (B-CLL) and related diseases. However, a major adverse side effect of ibrutinib is bleeding, including major hemorrhages. The bleeding associated with ibrutinib use is thought to be due to a combination of on-target irreversible Btk inhibition, as well as off-target inhibition of other kinases, including EGFR, ITK, JAK3, and Tec kinase. In this study, we investigated the effects of ibrutinib vs zanubrutinib (a more selective Btk inhibitor) on platelet activation, glycoprotein expression, and thrombus formation. Ibrutinib, but not zanubrutinib, induced a time- and dose-dependent shedding of GPIb-IX complex and integrin αIIbβ3, but not of GPVI and GPV, from the platelet surface. The shedding of GPIbα and GPIX was blocked by GM6001 and TAPI-2, an ADAM17 inhibitor but not ADAM10 inhibitor. Ibrutinib but not zanubrutinib treatment of human platelets increased ADAM17 activation. Pretreatment of C57BL/6 mice with ibrutinib (10 mg/kg), but not zanubrutinib (10 mg/kg), inhibited ex vivo and in vivo thrombus growth over time. Platelets from ibrutinib-treated patients with CLL showed reduced GPIb-IX complex and integrin αIIbβ3 surface expression and reduced ex vivo thrombus formation under arterial flow, which was not observed in zanubrutinib-treated patients. In mice, ibrutinib, but not zanubrutinib, led to increased soluble GPIbα and soluble αIIb levels in plasma. These data demonstrate that ibrutinib induces shedding of GPIbα and GPIX by an ADAM17-dependent mechanism and integrin αIIbβ3 by an unknown sheddase, and this process occurs in vivo to regulate thrombus formation.

[Haemorrhagic complications following ibrutinib intake after dermatological surgery]

INTRODUCTION

Ibrutinib is a selective oral inhibitor of Bruton's tyrosine kinase. It is used in haematology to treat lymphoid B disorders. Haemorrhagic complications in dermatological surgery are occasionally associated with the use of anti-platelet and/or anticoagulant medication. Herein, we report a case of haemorrhage under ibrutinib following skin surgery.

PATIENTS AND METHODS

A 70-year-old male patient began treatment with ibrutinib for chronic lymphocytic leukaemia had 2 basal cell carcinomas of the face. The next day he had a persistent haemorrhage lasting more than 48h, with no effects on the final scarring result.

DISCUSSION

Ibrutinib is a tyrosine kinase inhibitor whose mechanism of action plays a role in platelet adhesion. It is known to cause haemorrhaging, either spontaneously or following invasive procedures, especially at the beginning of treatment. In the case of low-risk haemorrhagic procedures in which bleeding may be controlled by mechanical haemostasis, ibrutinib should be discontinued 3 days before and after surgery. In the event of recent initiation of ibrutinib and in the absence of urgent dermatological management, it is preferable to schedule any surgical procedures 3 months after the start of ibrutinib.

Adverse cardiac effects of cancer therapies: cardiotoxicity and arrhythmia

Remarkable progress has been made in the development of new therapies for cancer, dramatically changing the landscape of treatment approaches for several malignancies and continuing to increase patient survival. Accordingly, adverse effects of cancer therapies that interfere with the continuation of best-possible care, induce life-threatening risks or lead to long-term morbidity are gaining increasing importance. Cardiovascular toxic effects of cancer therapeutics and radiation therapy are the epitome of such concerns, and proper knowledge, interpretation and management are needed and have to be placed within the context of the overall care of individual patients with cancer. Furthermore, the cardiotoxicity spectrum has broadened to include myocarditis with immune checkpoint inhibitors and cardiac dysfunction in the setting of cytokine release syndrome with chimeric antigen receptor T cell therapy. An increase in the incidence of arrhythmias related to inflammation such as atrial fibrillation can also be expected, in addition to the broadening set of cancer therapeutics that can induce prolongation of the corrected QT interval. Therefore, cardiologists of today have to be familiar not only with the cardiotoxicity associated with traditional cancer therapies, such as anthracycline, trastuzumab or radiation therapy, but even more so with an ever-increasing repertoire of therapeutics. This Review provides this information, summarizing the latest developments at the juncture of cardiology, oncology and haematology.

Patterns of use and safety of ibrutinib in real-life practice

AIMS

To provide real-life data on patterns of use and safety of ibrutinib.

METHODS

A cohort study including all patients initiating ibrutinib between 21 November 2014 and 21 November 2018, and followed for 1 year was conducted. Patient characteristics, ibrutinib use and adverse drug reactions (ADRs) were collected from medical records. Kaplan-Meier analysis estimated the probability of developing ibrutinib-associated serious ADRs (SADRs) with a 95% confidence interval (CI). A Cox proportional hazards model was used to investigate factors associated with SADR occurrence.

RESULTS

In total, 102 patients were included in the study. The median age was 70.3 years (interquartile range 64.7-75.6), the male/female gender ratio was 2.9. Almost half the patients (47.1%) were prescribed ibrutinib for chronic lymphocytic leukaemia (CLL). Forty-three patients (42.1%) permanently discontinued ibrutinib in the first year, mostly for progression (51.2%) or ADRs (32.6%). Forty-eight patients (47.1%) experienced at least one ibrutinib-associated SADR. Haematological, infectious and vascular disorders were the most frequent SADRs. The probability of developing ibrutinib-associated SADR was 35.1% (95% CI 26.3-45.7%) at 3 months, 44.8% (35.2%; 55.8%) at 6 months and 54.3% (44.0%; 65.2%) at 12 months. Age ≥80 years (hazard ratio [HR] 2.03; 95% CI 1.02-4.05) and CLL (HR 1.81; 95% CI 1.01-3.25) were significantly associated with a higher risk of SADR occurrence.

CONCLUSION

This study found a high cumulative incidence of ibrutinib-associated SADRs within the first year of treatment. In view of the risk of SADR, patients aged ≥80 years or treated for CLL deserve special attention.

Progress toward a Glycoprotein VI Modulator for the Treatment of Thrombosis

Pathogenic thrombus formation accounts for the etiology of many serious conditions including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. Despite the development of numerous anticoagulants and antiplatelet agents, the mortality rate associated with these diseases remains high. In recent years, however, significant epidemiological evidence and clinical models have emerged to suggest that modulation of the glycoprotein VI (GPVI) platelet receptor could be harnessed as a novel antiplatelet strategy. As such, many peptidic agents have been described in the past decade, while more recent efforts have focused on the development of small molecule modulators. Herein the rationale for targeting GPVI is summarized and the published GPVI modulators are reviewed, with particular focus on small molecules. A qualitative pharmacophore hypothesis for small molecule ligands at GPVI is also presented.

Diffuse Alveolar Hemorrhage Secondary to Ibrutinib Therapy in a Patient With Refractory Mantle Cell Lymphoma

Ibrutinib is a Bruton tyrosine kinase inhibitor that is approved by the FDA for the treatment of mantle cell lymphoma and other hematological malignancies. Bruton tyrosine kinases promote platelet aggregation, and, therefore, bleeding is a common side effect of ibrutinib. At least half of patients taking ibrutinib experience a bleeding event, and up to 10% may experience major bleeding. Patient-specific factors that predict bleeding events remain unknown. This report describes a case of diffuse alveolar hemorrhage in a 67-year-old male taking ibrutinib for refractory mantle cell lymphoma. He was initially admitted to the hospital for recurrence of mantle cell lymphoma and evidence of tumor lysis syndrome, including acute kidney injury and hyperuricemia. He was taking aspirin prior to being hospitalized and was thrombocytopenic. A deep vein thrombosis was noted following admission, and the patient was started on enoxaparin. Two days after starting ibrutinib as an inpatient, the patient developed diffuse alveolar hemorrhage, which was ultimately fatal. Bronchoscopy with bronchoalveolar lavage ruled out infectious and other etiologies. To our knowledge, this is the first case of diffuse alveolar hemorrhage associated with ibrutinib. Based on the available literature, it is unclear if the patient's recent aspirin use, concurrent enoxaparin, or thrombocytopenia was contributory. Further studies are necessary to clarify these patient-specific risks.

Promises and pitfalls of targeted agents in chronic lymphocytic leukemia

Targeted agents have significantly improved outcomes for patients with chronic lymphocytic leukemia, particularly high-risk subgroups for whom chemoimmunotherapy previously offered limited efficacy. Two classes of agent in particular, the Bruton tyrosine kinase inhibitors (e.g., ibrutinib) and the B-cell lymphoma 2 inhibitor, venetoclax, induce high response rates and durable remissions in the relapsed/refractory and frontline settings. However, maturing clinical data have revealed promises and pitfalls for both agents. These drugs induce remissions and disease control in the majority of patients, often in situations where modest efficacy would be expected with traditional chemoimmunotherapy approaches. Unfortunately, in the relapsed and refractory setting, both agents appear to be associated with an inevitable risk of disease relapse and progression. Emerging patterns of resistance are being described for both agents but a common theme appears to be multiple sub-clonal drivers of disease progression. Understanding these mechanisms and developing effective and safe methods to circumvent the emergence of resistance will determine the longer-term utility of these agents to improve patients' quality and length of life. Rational drug combinations, optimised scheduling and sequencing of therapy will likely hold the key to achieving these important goals.

Ibrutinib Resistance Mechanisms and Treatment Strategies for B-Cell lymphomas

Chronic activation of B-cell receptor (BCR) signaling via Bruton tyrosine kinase (BTK) is largely considered to be one of the primary mechanisms driving disease progression in B-Cell lymphomas. Although the BTK-targeting agent ibrutinib has shown promising clinical responses, the presence of primary or acquired resistance is common and often leads to dismal clinical outcomes. Resistance to ibrutinib therapy can be mediated through genetic mutations, up-regulation of alternative survival pathways, or other unknown factors that are not targeted by ibrutinib therapy. Understanding the key determinants, including tumor heterogeneity and rewiring of the molecular networks during disease progression and therapy, will assist exploration of alternative therapeutic strategies. Towards the goal of overcoming ibrutinib resistance, multiple alternative therapeutic agents, including second- and third-generation BTK inhibitors and immunomodulatory drugs, have been discovered and tested in both pre-clinical and clinical settings. Although these agents have shown high response rates alone or in combination with ibrutinib in ibrutinib-treated relapsed/refractory(R/R) lymphoma patients, overall clinical outcomes have not been satisfactory due to drug-associated toxicities and incomplete remission. In this review, we discuss the mechanisms of ibrutinib resistance development in B-cell lymphoma including complexities associated with genomic alterations, non-genetic acquired resistance, cancer stem cells, and the tumor microenvironment. Furthermore, we focus our discussion on more comprehensive views of recent developments in therapeutic strategies to overcome ibrutinib resistance, including novel BTK inhibitors, clinical therapeutic agents, proteolysis-targeting chimeras and immunotherapy regimens.

Cardiovascular Toxicities Associated With Ibrutinib

BACKGROUND

Ibrutinib has revolutionized treatment for several B-cell malignancies. However, a recent clinical trial where ibrutinib was used in a front-line setting showed increased mortality during treatment compared with conventional chemotherapy. Cardiovascular toxicities were suspected as the culprit but not directly assessed in the study.

OBJECTIVES

The purpose of this study was to identify and characterize cardiovascular adverse drug reactions (CV-ADR) associated with ibrutinib.

METHODS

This study utilized VigiBase (International pharmacovigilance database) and performed a disproportionality analysis using reporting odds ratios (ROR) and information component (IC) to determine whether CV-ADR and CV-ADR deaths were associated with ibrutinib. IC compares observed and expected values to find associations between drugs and adverse drug reactions using disproportionate Bayesian-reporting; IC₀₂₅ (lower end of the IC 95% credibility interval) >0 is significant.

RESULTS

This study identified 303 ibrutinib-associated cardiovascular deaths. Ibrutinib was associated with higher reporting of supraventricular arrhythmias (SVAs) (ROR: 23.1; 95% confidence interval: 21.6 to 24.7; p < 0.0001; IC₀₂₅: 3.97), central nervous system (CNS) hemorrhagic events (ROR: 3.7; 95% confidence interval: 3.4 to 4.1; p < 0.0001; IC₀₂₅: 1.63), heart failure (ROR: 3.5; 95% confidence interval: 3.1 to 3.8; p < 0.0001; IC₀₂₅: 1.46), ventricular arrhythmias (ROR: 4.7; 95% confidence interval: 3.7 to 5.9; p < 0.0001; IC₀₂₅: 0.96), conduction disorders (ROR: 3.5; 95% confidence interval: 2.7 to 4.6; p < 0.0001; IC₀₂₅: 0.76), CNS ischemic events (ROR: 2.2; 95% confidence interval: 2.0 to 2.5; p < 0.0001; IC₀₂₅: 0.73), and hypertension (ROR: 1.7; 95% confidence interval: 1.5 to 1.9; p < 0.0001; IC₀₂₅: 0.4). CV-ADR often occurred early after ibrutinib administration. Importantly, CV-ADR were associated with fatalities that ranged from ∼10% (SVAs and ventricular arrhythmias) to ∼20% (CNS events, heart failure, and conduction disorders). Ibrutinib-associated SVA portends poor prognosis when CNS events occur concomitantly, with 28.8% deaths (15 of 52 cases).

CONCLUSIONS

Severe and occasionally fatal cardiac events occur in patients exposed to ibrutinib. These events should be considered in patient care and in clinical trial designs. (Evaluation of Reporting of Cardio-vascular Adverse Events With Antineoplastic and Immunomodulating Agents [EROCA]; NCT03530215).

Revving the CAR - Combination strategies to enhance CAR T cell effectiveness

Chimeric antigen receptor (CAR) T cell therapy is currently approved for treatment of refractory B-cell malignancies. Response rates in these diseases are impressive by historical standards, but most patients do not have a durable response and there remains room for improvement. To date, CAR T cell activity has been even more limited in solid malignancies. These limitations are thought to be due to several pathways of resistance to CAR T cells, including cell-intrinsic mechanisms and the immunosuppressive tumor microenvironment. In this review, we discuss current experimental strategies that combine small molecules and monoclonal antibodies with CAR T cells to overcome these resistance mechanisms. We describe the biological rationale, pre-clinical data and clinical trials in progress that test the efficacy and safety of these combinations.

Drug Review: Ibrutinib

Ibrutinib is an irreversible BTK inhibitor, characterized by high selectivity and potency. It has revolutionized the therapy of B-cell lymphomas, especially chronic lymphocytic leukemia (CLL) and mantle cell lymphoma. Importantly, it has expanded the armamentarium for those patients who are refractory to conventional chemoimmunotherapy. This small-molecule inhibitor has shown efficacy in this difficult-to-treat subset – those with del(17p)/TP53-mutated CLL. Its immunomodulatory properties make it an excellent choice for combining with other immunotherapeutic agents such as venetoclax. The drug is not without drawbacks. The need for indefinite therapy and the presence of adverse effects such as infection, bleeding, hypertension, and arrhythmia temper our enthusiasm for this versatile drug. But overall, ibrutinib's favorable risk profile and lack of myelosuppression make it an ideal therapy for the elderly and those with multiple comorbidities.

Ibrutinib-Associated Cardiac Tamponade with Concurrent Antiplatelet Therapy

Ibrutinib is approved for the first-line treatment of chronic lymphocytic leukemia (CLL). A well-known side effect of ibrutinib therapy is increased bleeding risk, which ranges from mild mucocutaneous bleeding to rarely life-threatening hemorrhage. The increased bleeding tendency associated with ibrutinib is thought to be related to its effect on several platelet signaling pathways, which can be exacerbated in the setting of concurrent antiplatelet or anticoagulant therapy. We present an 82-year-old male with CLL on ibrutinib and concurrent antiplatelet therapy who developed cardiac tamponade due to a hemorrhagic pericardial effusion requiring emergent placement of a pericardial window. This case further highlights the risk of major bleeding in patients treated with ibrutinib and concurrent antiplatelet therapy.

Pharmacists' Role in Managing Patients with Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a hematologic malignancy that has seen significant advances in care over the last 5 years with the approval of oral agents such as ibrutinib and venetoclax for the treatment of this disease. As such, there has been a substantial shift away from the traditional chemotherapy infusions which have allowed patients greater autonomy with oral cancer therapies. This paradigm shift poses new challenges for the medical team, including drug-drug interactions, adherence counseling, and financial toxicity. Pharmacists are uniquely trained and equipped to help to manage the changing landscape of CLL care. From identifying common medications which may impair ibrutinib clearance to ensuring patients are on the appropriate anti-infective prophylaxis while receiving obinutuzumab, pharmacists can play a vital role in ensuring the highest quality of patient care. Furthermore, additional credentialing of clinical pharmacists in select states allows for independent visits with the pharmacists, allowing for greater involvement, particularly for initiation of venetoclax and management of ibrutinib-induced toxicities. Pharmacists are essential to both expanding and enhancing the care of patients with CLL and should be leveraged to improve patient outcomes whenever possible.

Oral Anticancer Therapy: Management of Drug Interactions

Oral anticancer therapy is increasingly integrated into the care of patients with cancer. Recognition and management of drug-drug interactions (DDIs) is critical to providing efficacious and safe anticancer treatment. DDIs with QTc-prolonging agents, anticoagulants, enzyme inducers and inhibitors, antidepressants, and acid suppressants are commonly encountered with anticancer therapies. Here, we review frequently observed DDIs and outline literature-supported suggestions for their management.

Is there a role for proton pump inhibitor prophylaxis in haematology patients?

While proton pump inhibitors (PPI) are widely prescribed as prophylaxis in selected haematology inpatient and outpatients, an informal survey of haematology units around Australia found wide variations in the specific indications for their use. This is consistent with a literature review which showed a paucity of robust evidence to support their use, specifically in chemotherapy-induced mucositis, thrombocytopenia or administration of high dose glucocorticosteroids in the absence of additional risk factors. Rationalising PPI prescribing is clinically important from both a cost and safety perspective, given the emerging evidence of adverse events associated with prolonged PPI administration. A review of prescribing practices at our institution over a 14-month period found that approximately 60% of myeloma, lymphoma and autograft patients received PPI prophylaxis during and beyond chemotherapy without an accepted indication. We encourage institutions to review their PPI prescribing practices with the intent of rationalising their use, and to conduct studies aiming to fill the substantial gaps in our knowledge.

Recommendations for ibrutinib treatment in patients with atrial fibrillation and/or elevated cardiovascular risk

Ibrutinib is the first clinically approved inhibitor of Bruton's tyrosine kinase, an enzyme that is essential for survival and proliferation of B‑cells by activating the B‑cell receptor signalling pathway. Ibrutinib has been shown to be highly effective in B‑cell malignancies in clinical trials and is recommended in current international guidelines as a first and/or second line treatment of chronic lymphocytic leukemia. The drug has a favorable tolerability and safety profile but the occurrence of specific side effects (e.g. atrial fibrillation, bleeding and hypertension) may complicate or be of concern for doctors and patients considering the use of this treatment. In many cases, however, it is not necessary to withhold this effective therapy. In contrast, ibrutinib treatment can be initiated or continued, if certain recommendations are followed. The possibilities of prevention, diagnosis and management of specific clinical situations are discussed in detail and recommendations are derived, which should facilitate ibrutinib use.

Biochemical characterization of tirabrutinib and other irreversible inhibitors of Bruton's tyrosine kinase reveals differences in on - and off - target inhibition

BACKGROUND

Bruton's tyrosine kinase (BTK) is a key component of the B-cell receptor (BCR) pathway and a clinically validated target for small molecule inhibitors such as ibrutinib in the treatment of B-cell malignancies. Tirabrutinib (GS-4059/ONO-4059) is a selective, once daily, oral BTK inhibitor with clinical activity against many relapsed/refractory B-cell malignancies.

METHODS

Covalent binding of tirabrutinib to BTK Cys-481 was assessed by LC-MSMS analysis of BTK using compound as a variable modification search parameter. Inhibition potency of tirabrutinib, ibrutinib, acalabrutinib, and spebrutinib against BTK and related kinases was studied in a dose-dependent manner either after a fixed incubation time (as used in conventional IC₅₀ studies) or following a time course where inactivation kinetics were measured.

RESULTS

Tirabrutinib irreversibly and covalently binds to BTK Cys-481. The inactivation efficiency k_inact/K_i was measured and used to calculate selectivity among different kinases for each of the four inhibitors studied. Tirabrutinib showed a k_inact/K_i value of 2.4 ± 0.6 × 10⁴ M^-1 s^-1 for BTK with selectivity against important off-targets.

CONCLUSIONS

For the BTK inhibitors tested in this study, analysis of the inactivation kinetics yielded a more accurate measurement of potency and selectivity than conventional single-time point inhibition measurements. Subtle but clear differences were identified between clinically tested BTK inhibitors which may translate into differentiated clinical efficacy and safety.

GENERAL SIGNIFICANCE

This is the first study that offers a detailed side-by-side comparison of four clinically-relevant BTK inhibitors with respect to their inactivation of BTK and related kinases.

Design of Potent and Selective Covalent Inhibitors of Bruton's Tyrosine Kinase Targeting an Inactive Conformation

Bruton's tyrosine kinase (BTK) is a member of the TEC kinase family and is selectively expressed in a subset of immune cells. It is a key regulator of antigen receptor signaling in B cells and of Fc receptor signaling in mast cells and macrophages. A BTK inhibitor will likely have a positive impact on autoimmune diseases which are caused by autoreactive B cells and immune-complex driven inflammation. We report the design, optimization, and characterization of potent and selective covalent BTK inhibitors. Starting from the selective reversible inhibitor 3 binding to an inactive conformation of BTK, we designed covalent irreversible compounds by attaching an electrophilic warhead to reach Cys481. The first prototype 4 covalently modified BTK and showed an excellent kinase selectivity including several Cys-containing kinases, validating the design concept. In addition, this compound blocked FcγR-mediated hypersensitivity in vivo. Optimization of whole blood potency and metabolic stability resulted in compounds such as 8, which maintained the excellent kinase selectivity and showed improved BTK occupancy in vivo.

Bleeding Disorders Associated with Cancer

Cancer can be associated with several distinct coagulation defects which can lead to bleeding complications. The primary hyperfibrinolytic syndrome associated with acute promyelocytic leukemia has been well recognized and is one of the most severe bleeding disorders. Acquired hemophilia, while rare and not only seen in the oncology setting, can be triggered by a malignancy and must be promptly recognized in order to prevent catastrophic hemorrhage. Other, less serious coagulopathic states have been linked to cancer, including acquired von Willebrand disease. Finally, several anti-neoplastic drugs can alter hemostasis and increase the risk of bleeding. A good understanding of this field can help mitigate the risk of complications in the cancer patient.

Central nervous system emergencies in haematological malignancies

Neurological emergencies are frequently catastrophic events in the course of haematological malignancies (HM) that, if not promptly recognized and treated, may lead to lethal outcomes or chronic sequelae. They may occur at any time during the disease course, but are more frequently observed following relapse. Practice guidelines are lacking in the management of most central nervous system (CNS) complications in HM. Herein we review the pathophysiology, presentation and treatment of elevated intracranial pressure, spinal cord compression, status epilepticus, neurovascular complications, CNS infection, leucostasis and hyperviscosity. Further, we discuss the expanding spectrum of neurological complications of old and novel treatments in HM.

Pentostatin, Cyclophosphamide, and Rituximab Followed by Alemtuzumab for Relapsed or Refractory Chronic Lymphocytic Leukemia: A Phase 2 Trial of the ECOG-Acrin Cancer Research Group (E2903)

Patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) may benefit from salvage chemoimmunotherapy (CIT). To explore further the use of CIT in the pre-novel agent era, ECOG-ACRIN undertook a phase 2 trial (E2903) for R/R CLL utilizing pentostatin, cyclophosphamide, and rituximab (PCR) followed by a consolidation course of alemtuzumab. This trial enrolled 102 patients with a median age of 64 years. Treatment consisted of 6 cycles of PCR followed by alemtuzumab for either 4 or 18 weeks depending on the initial response to PCR. The overall response after PCR (complete remission, CR, nodular partial remission, nPR, and partial remission, PR) was 55%. Major responses (CR or nPR) were achieved in 6%. The median overall survival (OS) and the median progression-free survival were 28 and 12 months, respectively. The most serious nonlethal adverse events were myelosuppression, febrile neutropenia, fatigue, nausea, and hyponatremia. PCR is an effective and well-tolerated nucleoside-based regimen for heavily pretreated CLL patients with R/R disease. The addition of alemtuzumab to CLL patients with a minor response (PR) or stable disease did not result in a significant number of higher responses (CR or nPR) nor an improvement in OS.

Acquired platelet function disorders

The possibility of an acquired platelet function disorder should be considered in patients who present with recent onset muco-cutaneous bleeding. Despite the availability of newer and faster platelet function assays, light transmission aggregometry (LTA) remains the preferred diagnostic test. This review examines and discusses the causes of acquired platelet dysfunction; most commonly drugs, dietary factors, medical disorders and procedures. In addition to well-known antiplatelet therapies, clinicians should be alert for newer drugs which can affect platelets, such as ibrutinib. There is little clinical trial evidence to guide the management of acquired platelet function defects, but we summarise commonly employed strategies, which include addressing the underlying cause, antifibrinolytic agents, desmopressin infusions, and in selected patients, platelet transfusions.