Evolving Strategies for the Treatment of Chronic Lymphocytic Leukemia in the Upfront Setting

Percutaneous coronary intervention and in-hospital outcomes in patients with leukemia: a nationwide analysis

OBJECTIVES

To examine the association between current leukemia diagnosis and in-hospital clinical outcomes in patients undergoing percutaneous coronary intervention (PCI) in the United States.

BACKGROUND

Leukemia is the most common hematological malignancy and is associated with an increased risk of thrombotic and bleeding complications in patients undergoing PCI. There are limited data around clinical outcomes of leukemia patients undergoing PCI.

METHODS

We used the National Inpatient Sample to investigate the outcomes of leukemia patients undergoing PCI between 2004 and 2014. Patients were then subdivided into diagnoses of acute myeloid leukemia (AML) or chronic myeloid leukemia and acute lymphoid leukemia or chronic lymphoid leukemia (CLL). Multiple logistic regressions were used to study the association of a leukemia diagnosis with in-hospital outcomes: mortality, bleeding, vascular and cardiac complications, and stroke.

RESULTS

There were 6,561,445 records of patients who underwent PCI during the study time, of which 15,789 patients had a diagnosis of leukemia. The most common leukemia subtype was CLL accounting for 75% of the cohort (n = 10,800). After multivariable adjustment, a leukemia diagnosis was associated with significantly increased odds of in-hospital mortality (odds ratio [OR]: 1.41; 95% confidence interval [CI]: [1.11-1.79]) and bleeding (OR: 1.87; 95% CI: [1.56-2.09]), whereas patients with AML had a fivefold increase of in-hospital mortality (OR: 5.38; 95% CI: [2.94-9.76]).

CONCLUSIONS

Patients with current diagnosis of leukemia are at increased risk of procedure-related complications following PCI. A multidisciplinary approach is needed among interventional cardiologists, oncologists, and hematologists to minimize procedural complications and improve outcomes in this high-risk cohort.

Low-count monoclonal B-cell lymphocytosis persists after seven years of follow up and is associated with a poorer outcome

Low-count monoclonal B-cell lymphocytosis is defined by the presence of very low numbers of circulating clonal B cells, usually phenotypically similar to chronic lymphocytic leukemia cells, whose biological and clinical significance remains elusive. Herein, we re-evaluated 65/91 low-count monoclonal B-cell lymphocytosis cases (54 chronic lymphocytic leukemia-like and 11 non-chronic lymphocytic leukemia-like) followed-up for a median of seven years, using high-sensitivity flow cytometry and interphase fluorescence in situ hybridization. Overall, the clone size significantly increased in 69% of low-count monoclonal B-cell lymphocytosis cases, but only one subject progressed to high-count monoclonal B-cell lymphocytosis. In parallel, the frequency of cytogenetic alterations increased over time (32% vs. 61% of cases, respectively). The absolute number of the major T-cell and natural killer cell populations also increased, but only among chronic lymphocytic leukemia-like cases with increased clone size vs. age- and sex-matched controls. Although progression to chronic lymphocytic leukemia was not observed, the overall survival of low-count monoclonal B-cell lymphocytosis individuals was significantly reduced vs. non-monoclonal B-cell lymphocytosis controls (P=0.03) plus the general population from the same region (P≤0.001), particularly among females (P=0.01); infection and cancer were the main causes of death in low-count monoclonal B-cell lymphocytosis. In summary, despite the fact that mid-term progression from low-count monoclonal B-cell lymphocytosis to high-count monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia appears to be unlikely, these clones persist at increased numbers, usually carrying more genetic alterations, and might thus be a marker of an impaired immune system indirectly associated with a poorer outcome, particularly among females.

Emerging role of BCR signaling inhibitors in immunomodulation of chronic lymphocytic leukemia

Approved therapies that target the B-cell receptor (BCR) signaling pathway, such as ibrutinib and idelalisib, are known to show activity in chronic lymphocytic leukemia (CLL) via their direct effects on crucial survival pathways in malignant B cells. However, these therapies also have effects on T cells in CLL by mediating toxicity and possibly controlling disease. By focusing on the effects of BCR signaling inhibitors on the T-cell compartment, we may gain new insights into the comprehensive biological outcomes of systemic treatment to further understand mechanisms of drug efficacy, predict the toxicity or adverse events, and identify novel combinatorial therapies. Here, we review T-cell abnormalities in preclinical models and patient samples, finding that CLL T cells orchestrate immune dysfunction and immune-related complications. We then continue to address the effects of clinically available small molecule BCR signaling inhibitors on the immune cells, especially T cells, in the context of concomitant immune-mediated adverse events and implications for future treatment strategies. Our review suggests potentially novel mechanisms of action related to BCR inhibitors, providing a rationale to extend their use to other cancers and autoimmune disorders.