Hypertension in Patients Treated With Ibrutinib for Chronic Lymphocytic Leukemia

Hypertension treatment for patients receiving ibrutinib: a multicenter retrospective study

ABSTRACT

Although Bruton tyrosine kinase inhibitors (BTKis) are generally well tolerated and less toxic than chemotherapy alternatives used to treat lymphoid malignancies, BTKis like ibrutinib have the potential to cause new or worsening hypertension (HTN). Little is known about the optimal treatment of BTKi-associated HTN. Randomly selected patients with lymphoid malignancies on a BTKi and antihypertensive drug(s) and with at least 3 months of follow-up data were sorted into 2 groups: those diagnosed with HTN before BTKi initiation (prior-HTN), and those diagnosed with HTN after BTKi initiation (de novo HTN). Generalized estimating equations assessed associations between time varying mean arterial pressures (MAPs) and individual anti-HTN drug categories. Of 196 patients included in the study, 118 had prior-HTN, and 78 developed de novo HTN. Statistically significant mean MAP reductions were observed in patients with prior-HTN who took β blockers (BBs) with hydrochlorothiazide (HCTZ), (-5.05 mmHg; 95% confidence interval [CI], 10.0 to -0.0596; P = .047), and patients diagnosed with de novo HTN who took either an angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) with HCTZ (-5.47 mmHg; 95% CI, 10.9 to -0.001; P = .05). These regimens also correlated with the greatest percentages of normotensive MAPs. Treatment of HTN in patients taking a BTKi is challenging and may require multiple antihypertensives. Patients with prior-HTN appear to benefit from combination regimens with BBs and HCTZ, whereas patients with de novo HTN appear to benefit from ACEi/ARBs with HCTZ. These results should be confirmed in prospective studies.

Risk of New-Onset Atrial Fibrillation Associated With Targeted Treatment of Lymphoma

Background

Lymphoma treatment may be associated with new-onset atrial fibrillation (AF), especially among patients treated with Bruton tyrosine kinase inhibitors (BTKi).

Objectives

The authors sought to assess the risk of new-onset AF, AF risk factors, and the impact of AF on mortality in patients with lymphoma and no history of AF.

Methods

The University of Rochester Medical Center Lymphoma Database was used to identify patients. The primary outcome was any AF episode identified using the International Classification of Diseases-10th Revision codes. Multivariable Cox regression was used to assess the risk of AF through the use of a time-dependent covariate for treatment overall as well as separate time-varying measures of BTKi (mainly ibrutinib) and non-BTKi treatment. The relative risk of all-cause mortality was determined using Cox proportional hazards analysis.

Results

Among 1,957 lymphoma patients, the rate of AF at 5-years following initiation of BTKi treatment was higher (25%) compared to those receiving non-BTKi therapy (8%), and those receiving no treatment (4%). Multivariable analysis showed that BTKi treatment was associated with pronounced increased risk for AF compared to no treatment (HR: 5.07 [95% CI: 2.88-8.90; P < 0.001]). Non-BTKi treatment was associated with an increased risk of AF compared to no treatment (HR: 1.82 [95% CI: 1.14-2.89; P = 0.012]). Risk factors for the development of AF included age ≥64 years, male sex, hypertension, and lymphoma treatment. New AF was associated with an increased risk for subsequent mortality (HR: 3.71 [95% CI: 2.59-5.31]).

Conclusions

Patients undergoing lymphoma treatment, especially those with high-risk features, may benefit from AF surveillance.

Cardiovascular Toxicities of BTK Inhibitors in Chronic Lymphocytic Leukemia: JACC: CardioOncology State-of-the-Art Review

Over the past decade, the treatment landscape of chronic lymphocytic leukemia (CLL) has dramatically changed, shifting from cytotoxic chemotherapy to targeted therapies. Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the treatment of CLL and are increasingly applied in many other malignancies. However, ibrutinib, the first BTK inhibitor approved, is associated with serious toxicities, including atrial fibrillation in up to 38% of patients, ventricular arrhythmias, and other cardiovascular toxicities. Emerging data suggest several newer BTK inhibitors (eg, acalabrutinib, zanubrutinib) are still associated with cardiotoxic risks. This review examines the current state of evidence, including incidence rates, risk factors, mechanisms, and management strategies of cardiovascular toxicities with BTK inhibitors and other CLL therapies. We specifically focus on atrial fibrillation, ventricular arrhythmias/sudden death, hypertension, heart failure, bleeding, and stroke. We also touch on other emerging BTK therapies (eg, pirtobrutinib). Finally, we highlight key unanswered questions and future directions of research.

Long-term outcomes in patients with chronic lymphocytic leukemia treated with ibrutinib: Focus on hypertension and cardiovascular toxicity

BACKGROUND

Continuous ibrutinib administration is needed to maintain efficacy in patients with chronic lymphocytic leukemia (CLL) and, as such, long-term toxicity is a concern. The authors report the 5-year follow-up of patients with CLL who received treatment with ibrutinib with a focus on hypertension and cardiovascular toxicities.

METHODS

Patient characteristics were assessed, including blood pressure, cardiovascular disease, disease progression, and death. Univariate logistic regression analysis assessed the relation of patient characteristics and the development of new or worsened hypertension. The incidence of hypertensive outcomes was evaluated using competing risk. Survival was estimated using the Kaplan-Meier method.

RESULTS

Three hundred patients with CLL who were treated with ibrutinib on clinical trials were included. The median patient age at study enrollment was 65 years (range, 29-83 years). Seventy percent of patients were men, and 88% were Caucasian. Sixty-nine percent of patients had hypertension at baseline, and 47% were on antihypertensive medication. Eighty-eight percent had relapsed or refractory CLL. New-onset and worsening hypertension were common, occurring in 68.5% and 38% of patients, respectively. Systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥100 mm Hg was observed in 16.9% of patients. Hypertension was reversible after ibrutinib discontinuation. Older age, male sex, tobacco use, and chronic kidney disease were associated with ibrutinib-related hypertension. Baseline hypertension was not associated with major adverse cardiovascular events in ibrutinib-treated patients nor with event-free or overall survival.

CONCLUSIONS

Hypertension is a common toxicity in patients with CLL who receive ibrutinib but is manageable in most patients. Other than chronic kidney disease, baseline cardiovascular disease did not affect ibrutinib-related hypertension nor was hypertension associated with major adverse cardiovascular events or survival.

PLAIN LANGUAGE SUMMARY

Ibrutinib is an effective treatment for patients with chronic lymphocytic leukemia. Ibrutinib is a well tolerated therapy, however hypertension can develop or worsen in patients receiving ibrutinib and other cardiovascular events are significant challenges to the use of this drug. This may be particularly true in patients with heart disease. Short-term side effects may worsen heart disease, but the long-term impact is unknown. The long-term results of ibrutinib on heart disease and hypertension are described.

Cardiotoxicities of Novel Therapies in Hematological Malignancies: Monoclonal Antibodies and Enzyme Inhibitors

Monoclonal antibodies (mAB) selectively target leukemia surface antigens and work by either blocking cell surface receptors or triggering the target cell's destruction. Similarly, enzyme inhibitors bind to complex molecular platforms and induce downstream mechanisms that trigger cell death. These are used in a variety of hematologic malignancies. Yet, they also elicit severe immune-mediated reactions as biological agents that require careful monitoring. Cardiovascular effects include cardiomyopathy, ventricular dysfunction, cardiac arrest, and acute coronary syndrome. While there have been scattered reviews of mAB and enzyme inhibitors, a consolidated resource regarding their cardiovascular risk profile is lacking. We provide general recommendations for initial screening and serial monitoring based on the literature.

Established and Emerging Cancer Therapies and Cardiovascular System: Focus on Hypertension-Mechanisms and Mitigation

Cardiovascular disease and cancer are 2 of the leading causes of death worldwide. Although improvements in outcomes have been noted for both disease entities, the success of cancer therapies has come at the cost of at times very impactful adverse events such as cardiovascular events. Hypertension has been noted as both, a side effect as well as a risk factor for the cardiotoxicity of cancer therapies. Some of these dynamics are in keeping with the role of hypertension as a cardiovascular risk factor not only for heart failure, but also for the development of coronary and cerebrovascular disease, and kidney disease and its association with a higher morbidity and mortality overall. Other aspects such as the molecular mechanisms underlying the amplification of acute and long-term cardiotoxicity risk of anthracyclines and increase in blood pressure with various cancer therapeutics remain to be elucidated. In this review, we cover the latest clinical data regarding the risk of hypertension across a spectrum of novel anticancer therapies as well as the underlying known or postulated pathophysiological mechanisms. Furthermore, we review the acute and long-term implications for the amplification of the development of cardiotoxicity with drugs not commonly associated with hypertension such as anthracyclines. An outline of management strategies, including pharmacological and lifestyle interventions as well as models of care aimed to facilitate early detection and more timely management of hypertension in patients with cancer and survivors concludes this review, which overall aims to improve both cardiovascular and cancer-specific outcomes.

A real-world study to assess the association of cardiovascular adverse events (CVAEs) with ibrutinib as first-line (1L) treatment for patients with chronic lymphocytic leukaemia (CLL) in the United States

Ibrutinib, a Bruton's tyrosine kinase inhibitor, is often used as first-line (1L) treatment of chronic lymphocytic leukaemia (CLL); however, it is associated with an increased risk for cardiovascular adverse events (CVAEs). This real-world study adds to existing literature by simultaneously investigating the correlation between pre-existing CV risk factors and the relative cardiotoxicity of ibrutinib vs other therapies in CLL/small lymphocytic lymphoma (SLL). Using a real-world database, the risk of subsequent CVAEs (any CVAE, atrial fibrillation [AF], or hypertension) were compared among patients who received 1L ibrutinib monotherapy or another type of non-ibrutinib therapy, grouped as intensive (IT) or non-intensive therapy (NIT). Each patient's baseline CV risk was estimated using the Framingham risk score. Inverse probability treatment weighting was incorporated into a logistic regression model to reduce baseline imbalance. Results showed ibrutinib was significantly associated with higher risk of CVAEs regardless of baseline CV risk. Compared with IT, odds ratios of any CVAE, hypertension, or AF were 2.61, 3.66, and 3.02, respectively vs 1.88, 2.13, and 2.46, respectively, with NIT. Sensitivity analyses confirmed the findings were robust. These results suggest clinical caution should be taken when selecting ibrutinib for patients with CLL/SLL, especially in those with high baseline CV risk.

Long-term safety profile of tirabrutinib: final results of a Japanese Phase I study in patients with relapsed or refractory B-cell malignancies

Tirabrutinib is a Bruton's tyrosine kinase inhibitor for treating B-cell malignancies. We report the final results of a Phase I study of tirabrutinib in 17 Japanese patients with B-cell malignancies. Patients were administered tirabrutinib at a dose of 160 mg, 320 mg, or 480 mg once daily, or 300 mg twice daily (N = 3, 3, 4, and 7, respectively). Three patients continued tirabrutinib until study completion (November 30, 2020). Adverse events (AEs) occurred in all 17 patients, with Grade 3-4 AEs in 8 (47.1%), serious AEs in 7 (41.2%), drug-related AEs in 16 (94.1%), and Grade 3-4 drug-related AEs in 6 (35.3%). Drug-related AEs reported in 3 or more patients were rash, vomiting, neutropenia, arthralgia, and malaise. One additional serious AE (benign neoplasm of the lung, unrelated to tirabrutinib) occurred after the previous data cutoff (January 4, 2018). Tirabrutinib administration and response assessment were continued for over 4 years in 4 patients. The overall response rate was 76.5% (13/17 patients). The median (range) time to response and duration of response were 0.9 (0.9-5.9) months and 2.59 (0.08-5.45) years, respectively. These findings demonstrate the long-term safety and efficacy of tirabrutinib in Japanese patients with B-cell malignancies.Clinical trial registration: JapicCTI-142682 ( http://www.clinicaltrials.jp/ ).

Selecting the optimal BTK inhibitor therapy in CLL: rationale and practical considerations

Bruton’s tyrosine kinase (BTK) inhibitors have dramatically changed the treatment of newly diagnosed and relapsed/refractory chronic lymphocytic leukemia (CLL). Ibrutinib, acalabrutinib, and zanubrutinib are Food and Drug Administration (FDA)-approved BTK inhibitors that have all demonstrated progression-free survival (PFS) benefit compared with chemoimmunotherapy. The efficacy of these agents compared to one another is under study; however, current data suggest they provide similar efficacy. Selectivity for BTK confers different adverse effect profiles, and longer follow-up and real-world use have characterized side effects over time. The choice of BTK inhibitor is largely patient-specific, and this review aims to highlight the differences among the agents and guide the choice of BTK inhibitor in clinical practice.

Hypertension and incident cardiovascular events after next-generation BTKi therapy initiation

BACKGROUND

Post-market analyses revealed unanticipated links between first-generation Bruton's tyrosine kinase inhibitor (BTKi) therapy, ibrutinib, and profound early hypertension. Yet, whether this is seen with novel selective second (next)-generation BTKi therapy, acalabrutinib, is unknown.

METHODS

Leveraging a large cohort of consecutive B cell cancer patients treated with acalabrutinib from 2014 to 2020, we assessed the incidence and ramifications of new or worsened hypertension [systolic blood pressure (SBP) ≥ 130 mmHg] after acalabrutinib initiation. Secondary endpoints were major cardiovascular events (MACE: arrhythmias, myocardial infarction, stroke, heart failure, cardiac death) and disease progression. Observed incident hypertension rates were compared to Framingham heart-predicted and ibrutinib-related rates. Multivariable regression and survival analysis were used to define factors associated with new/worsened hypertension and MACE, and the relationship between early SBP increase and MACE risk. Further, the effect of standard antihypertensive classes on the prevention of acalabrutinib-related hypertension was assessed.

RESULTS

Overall, from 280 acalabrutinib-treated patients, 48.9% developed new/worsened hypertension over a median of 41 months. The cumulative incidence of new hypertension by 1 year was 53.9%, including 1.7% with high-grade (≥ 3) hypertension. Applying the JNC 8 cutoff BP of ≥ 140/90 mmHg, the observed new hypertension rate was 20.5% at 1 year, > eightfold higher than the Framingham-predicted rate of 2.4% (RR 8.5, P < 0.001), yet 34.1% lower than ibrutinib (12.9 observed-to-expected ratio, P < 0.001). In multivariable regression, prior arrhythmias and Black ancestry were associated with new hypertension (HR 1.63, HR 4.35, P < 0.05). The degree of SBP rise within 1 year of treatment initiation predicted MACE risk (42% HR increase for each + 5 mmHg SBP rise, P < 0.001). No single antihypertensive class prevented worsened acalabrutinib-related hypertension.

CONCLUSIONS

Collectively, these data suggest that hypertension may be a class effect of BTKi therapies and precedes major cardiotoxic events.

Use of BTK Inhibitors in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL): A Practical Guidance

The treatment landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has changed significantly since the development of oral Bruton’s tyrosine kinase (BTK) inhibitors. While chemoimmunotherapy was previously the standard of care for first-line treatment, BTK inhibitors have proven to be a highly effective and safe therapeutic option for CLL/SLL, and now constitute one of the preferred first-line options. Ibrutinib, the first approved covalent BTK inhibitor in CLL/SLL, has the most long-term data supporting its efficacy in CLL/SLL treatment although is associated with increased risk of cardiovascular and hemorrhage adverse events due to off-target kinase inhibition. The second-generation covalent BTK inhibitors, including acalabrutinib and zanubrutinib, are more selective to BTK with less off-target effects. Resistance to covalent BTK inhibitors may emerge over time due to mutations in BTK and downstream kinases. Novel non-covalent BTK inhibitors currently being studied are showing promising activities to overcome such resistance. In this review, we discuss the role of BTK inhibitors in treatment of CLL/SLL, review the data that led to approval of BTK inhibitors in CLL/SLL, outline the toxicity profile of each approved BTK inhibitor and management, and give practical guidance on how to select the most appropriate agent for treatment.

Pre-existing cardiovascular disease increases risk of atrial arrhythmia and mortality in cancer patients treated with Ibrutinib

Background

Ibrutinib is a Bruton’s tyrosine kinase inhibitor used in the treatment of hematological malignancies. The most common cardiotoxicity associated with ibrutinib is atrial arrhythmia (atrial fibrillation and flutter). It is known that patients with cardiovascular disease (CVD) are at an increased risk for developing atrial arrhythmia. However, the rate of atrial arrhythmia in patients with pre-existing CVD treated with ibrutinib is unknown.

Objective

This study examined whether patients with pre-existing CVD are at a higher risk for developing atrial arrhythmias compared to those without prior CVD.

Methods

A single-institution retrospective chart review of patients with no prior history of atrial arrhythmia treated with ibrutinib from 2012 to 2020 was performed. Patients were grouped into two cohorts: those with CVD (known history of coronary artery disease, heart failure, pulmonary hypertension, at least moderate valvular heart disease, or device implantation) and those without CVD. The primary outcome was incidence of atrial arrhythmia, and the secondary outcomes were all-cause mortality, risk of bleeding, and discontinuation of ibrutinib. The predictors of atrial arrhythmia (namely atrial fibrillation) were assessed using logistic regression. A Cox-Proportional Hazard model was created for mortality.

Results

Patients were followed for a median of 1.1 years. Among 217 patients treated with ibrutinib, the rate of new-onset atrial arrhythmia was nearly threefold higher in the cohort with CVD compared to the cohort without CVD (17% vs 7%, p = 0.02). Patients with CVD also demonstrated increased adjusted all-cause mortality (OR 1.9, 95% CI 1.06-3.41, p = 0.01) and decreased survival probability (43% vs 54%, p = 0.04) compared to those without CVD over the follow-up period. There were no differences in risk of bleeding or discontinuation between the two cohorts.

Conclusions

Pre-existing cardiovascular disease was associated with significantly higher rates of atrial arrhythmia and mortality in patients with hematological malignancies managed with ibrutinib.

Management of ibrutinib treatment in patients with B-cell malignancies: clinical practice in Portugal and multidisciplinary recommendations

OBJECTIVES

Ibrutinib, a potent inhibitor of the Bruton tyrosine kinase, has revolutionized the treatment of many B-cell malignancies. Ibrutinib has an established favorable toxicity profile with up to 8 years of experience in clinical trials; however, despite ibrutinib's favorable toxicity profile, dose reductions and treatment discontinuations are becoming more evident in clinical practice, particularly in the setting of specific clinical contexts and patient characteristics. This manuscript is set to provide practical recommendations on the management of patients treated with this agent in daily practice.

METHODS

A group of multidisciplinary experts from Portugal met to discuss and highlight practical recommendations, supported on both literature and clinical insights, for the management of the treatment with ibrutinib.

RESULTS/DISCUSSION

Handling of both toxicities and drug-drug interactions during ibrutinib treatment poses several challenges to healthcare providers and can benefit from a multidisciplinary approach. The involvement of specialties, such as cardiology, infectiology and pharmacology, can bring an added value to patient care, not only in anticipating/managing safety issues and dose adjustments but also in enhancing adherence to treatment, ultimately improving the risk/benefit balance.

CONCLUSION

By involving a multidisciplinary group of experts, this work provides a set of key recommendations to optimize care and outcomes for ibrutinib-treated patients. Despite not being a fully comprehensive review on the topic, it is intended as a framework to hematologists and other healthcare professionals who manage these patients in their daily clinical practice.

Vascular Impact of Cancer Therapies: The Case of BTK (Bruton Tyrosine Kinase) Inhibitors

Novel targeted cancer therapies have revolutionized oncology therapies, but these treatments can have cardiovascular complications, which include heterogeneous cardiac, metabolic, and vascular sequelae. Vascular side effects have emerged as important considerations in both cancer patients undergoing active treatment and cancer survivors. Here, we provide an overview of vascular effects of cancer therapies, focusing on small-molecule kinase inhibitors and specifically inhibitors of BTK (Bruton tyrosine kinase), which have revolutionized treatment and prognosis for B-cell malignancies. Cardiovascular side effects of BTK inhibitors include atrial fibrillation, increased risk of bleeding, and hypertension, with the former 2 especially providing a treatment challenge for the clinician. Cardiovascular complications of small-molecule kinase inhibitors can occur through either on-target (targeting intended target kinase) or off-target kinase inhibition. We will review these concepts and focus on the case of BTK inhibitors, highlight the emerging data suggesting an off-target effect that may provide insights into development of arrhythmias, specifically atrial fibrillation. We believe that cardiac and vascular sequelae of novel targeted cancer therapies can provide insights into human cardiovascular biology.

Etiology and management of hypertension in patients with cancer

The pathophysiology of hypertension and cancer are intertwined. Hypertension has been associated with an increased likelihood of developing certain cancers and with higher cancer-related mortality. Moreover, various anticancer therapies have been reported to cause new elevated blood pressure or worsening of previously well-controlled hypertension. Hypertension is a well-established risk factor for the development of cardiovascular disease, which is rapidly emerging as one of the leading causes of death and disability in patients with cancer. In this review, we discuss the relationship between hypertension and cancer and the role that hypertension plays in exacerbating the risk for anthracycline- and trastuzumab-induced cardiomyopathy. We then review the common cancer therapies that have been associated with the development of hypertension, including VEGF inhibitors, small molecule tyrosine kinase inhibitors, proteasome inhibitors, alkylating agents, glucocorticoids, and immunosuppressive agents. When available, we present strategies for blood pressure management for each drug class. Finally, we discuss blood pressure goals for patients with cancer and strategies for assessment and management. It is of utmost importance to maintain optimal blood pressure control in the oncologic patient to reduce the risk of chemotherapy-induced cardiotoxicity and to decrease the risk of long-term cardiovascular disease.

Cardiotoxicity of Novel Targeted Hematological Therapies

Chemotherapy-related cardiac dysfunction, also known as cardiotoxicity, is a group of drug-related adverse events negatively affecting myocardial structure and functions in patients who received chemotherapy for cancer treatment. Clinical manifestations can vary from life-threatening arrythmias to chronic conditions, such as heart failure or hypertension, which dramatically reduce quality of life of cancer survivors. Standard chemotherapy exerts its toxic effect mainly by inducing oxidative stress and genomic instability, while new targeted therapies work by interfering with signaling pathways important not only in cancer cells but also in myocytes. For example, Bruton’s tyrosine kinase (BTK) inhibitors interfere with class I phosphoinositide 3-kinase isoforms involved in cardiac hypertrophy, contractility, and regulation of various channel forming proteins; thus, off-target effects of BTK inhibitors are associated with increased frequency of arrhythmias, such as atrial fibrillation, compared to standard chemotherapy. In this review, we summarize current knowledge of cardiotoxic effects of targeted therapies used in hematology.

Chemotherapy-free frontline therapy for CLL: is it worth it?

The treatment of chronic lymphocytic leukemia (CLL) embodies one of the great success stories in translational research, with the development of therapies aimed at disrupting crucial pathways that allow for the survival and proliferation of the malignant clone. The arrival of targeted agents into our armamentarium, along with the advent of novel monoclonal antibodies that can achieve deeper remissions, has steered the field to a new treatment paradigm. Given the panoply of therapeutic options available, the question arises whether chemotherapy still has a role in the management of CLL. The novel targeted agents, which include the Bruton's tyrosine kinase inhibitors, ibrutinib and acalabrutinib, along with the B-cell lymphoma-2 inhibitor, venetoclax, are highly effective in achieving a response with improved remission duration and survival, particularly in high-risk patients. Despite this major progress, the new agents bring a unique set of toxicities unlike those associated with cytotoxic chemotherapy. There is a paucity of head-to-head comparisons among all of the novel agents, because their approval was based on randomization against traditional chemoimmunotherapeutic regimens. Parallel to the increase in the number of available targeted agents, there has been a significant improvement in quality of life and life expectancy of the patients with a CLL diagnosis over the last decade. Our review will examine whether "chemotherapy-free" frontline treatment approaches are worth the associated risks. Our goal is to help identify optimal treatment strategies tailored to the individual by reviewing available data on monotherapy vs combination strategies, depth of response, treatment duration, and potential toxicities.

Bruton tyrosine kinase inhibitors for the frontline treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (cll) is the most commonly diagnosed adult leukemia in Canada. Biologic heterogeneity of cll between patients results in variable disease trajectories and responses to therapy. Notably, compared with patients lacking high-risk features, those with such features-such as deletions in chromosome 17p, aberrations in the TP53 gene, or unmutated immunoglobulin heavy chain variable region genes-experience inferior outcomes and responses to standard chemoimmunotherapy. Novel agents that target the B cell receptor signalling pathway, such as Bruton tyrosine kinase (btk) inhibitors, have demonstrated clinical efficacy and safety in patients with treatment-naïve cll, particularly those with high-risk features. However, given the current lack of head-to-head trials comparing btk inhibitors, selection of the optimal btk inhibitor for patients with cll is unclear and requires consideration of multiple factors. In the present review, we focus on the efficacy, safety, and pharmacologic features of the btk inhibitors that are approved or under clinical development, and we discuss the practical considerations for the use of those agents in the Canadian treatment landscape.

Hypertensive Cardiotoxicity in Cancer Treatment-Systematic Analysis of Adjunct, Conventional Chemotherapy, and Novel Therapies-Epidemiology, Incidence, and Pathophysiology

Cardiotoxicity is the umbrella term for cardiovascular side effects of cancer therapies. The most widely recognized phenotype is left ventricular dysfunction, but cardiotoxicity can manifest as arrhythmogenic, vascular, myocarditic and hypertensive toxicities. Hypertension has long been regarded as one of the most prevalent and modifiable cardiovascular risk factors in the general population, but its relevance during the cancer treatment journey may be underestimated. Hypertensive cardiotoxicity occurs de novo in a substantial proportion of treated cancer patients. The pathology is incompletely characterized—natriuresis and renin angiotensin system interactions play a role particularly in conventional treatments, but in novel therapies endothelial dysfunction and the interaction between the cancer and cardiac kinome are implicated. There exists a treatment paradox in that a significant hypertensive response not only mandates anti-hypertensive treatment, but in fact, in certain cancer treatment scenarios, hypertension is a predictor of cancer treatment efficacy and response. In this comprehensive review of over 80,000 patients, we explored the epidemiology, incidence, and mechanistic pathophysiology of hypertensive cardiotoxicity in adjunct, conventional chemotherapy, and novel cancer treatments. Conventional chemotherapy, adjunct treatments, and novel targeted therapies collectively caused new onset hypertension in 33–68% of treated patients. The incidence of hypertensive cardiotoxicity across twenty common novel therapies for any grade hypertension ranged from 4% (imatinib) to 68% (lenvatinib), and high grade 3 or 4 hypertension in <1% (imatinib) to 42% (lenvatinib). The weighted average effect was all-grade hypertension in 24% and grade 3 or 4 hypertension in 8%.

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.

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.