Novel Targeted Therapies for Chronic Lymphocytic Leukemia in Elderly Patients: A Systematic Review

Prognosis of older adults with chronic lymphocytic leukemia: A Surveillance, Epidemiology, and End Results-Medicare cohort study

INTRODUCTION

While prognosis for patients with chronic lymphocytic leukemia (CLL) has improved over time in younger adults, only modest improvements have occurred in older adults. We conducted a descriptive study of prognosis in older adults with CLL.

MATERIALS AND METHODS

We used data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database from 2003 to 2016. We identified older adults (≥66 years) diagnosed with primary CLL between 2004 and 2015 (Overall Cohort). A subset who initiated CLL-directed therapy during the year following diagnosis was also identified (Treated Cohort). Both cohorts were matched to Medicare beneficiaries without cancer based on age, sex, and region. For each year from 2004 to 2013, three-year survival for patients with CLL and non-cancer comparators was described using Kaplan-Meier analysis. Inverse probability weighted Cox regression models were used to compare survival in the CLL and non-cancer comparator cohorts, accounting for demographic information and comorbidity and frailty indices. Among older adults with CLL, ten-year cause-specific cumulative mortality was estimated using Aalen-Johansen estimators that accounted for competing risks. Predictors of cause-specific mortality, including comorbidity and frailty burden, were assessed using sub-distribution hazards models.

RESULTS

In the Overall Cohort, three-year survival increased non-monotonically from 71.4% in 2004 to 73.4% in 2013, with a peak of 74.4% in 2011, and was lower than survival in non-cancer comparators (78.3% in 2004 to 83.2% in 2013). In the Treated Cohort, three-year survival was 56.3% in 2004 and 56.5% in 2013, with a peak of 64.2% in 2011. Cox models suggested that survival in the Treated Cohort was approaching survival in non-cancer comparators after 2011 (hazard ratio = 1.04, 95% confidence interval, 0.93-1.17). Ten-year cumulative mortality was 68.6% in the Overall Cohort and 81.7% in the Treated Cohort, with most deaths attributed to non-CLL causes. In the sub-distribution hazards models, age, year of diagnosis, frailty, and comorbidities were all associated with prognosis.

DISCUSSION

Prognosis in older adults has been stable over time and most patients with CLL die from non-CLL causes. CLL-directed treatment decision-making in older adults should consider age-related factors, such as comorbidity and frailty.

Bruton's Tyrosine Kinase Inhibitors (BTKIs): Review of Preclinical Studies and Evaluation of Clinical Trials

In the last few decades, there has been a growing interest in Bruton's tyrosine kinase (BTK) and the compounds that target it. BTK is a downstream mediator of the B-cell receptor (BCR) signaling pathway and affects B-cell proliferation and differentiation. Evidence demonstrating the expression of BTK on the majority of hematological cells has led to the hypothesis that BTK inhibitors (BTKIs) such as ibrutinib can be an effective treatment for leukemias and lymphomas. However, a growing body of experimental and clinical data has demonstrated the significance of BTK, not just in B-cell malignancies, but also in solid tumors, such as breast, ovarian, colorectal, and prostate cancers. In addition, enhanced BTK activity is correlated with autoimmune disease. This gave rise to the hypothesis that BTK inhibitors can be beneficial in the therapy of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), Sjögren's syndrome (SS), allergies, and asthma. In this review article, we summarize the most recent findings regarding this kinase as well as the most advanced BTK inhibitors that have been developed to date and their clinical applications mainly in cancer and chronic inflammatory disease patients.

Aberrantly expressed Wnt5a in nurse-like cells drives resistance to Venetoclax in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of neoplastic B lymphocytes with high levels of Wnt5a in the plasma. Currently, the cell source of Wnt5a remains controversial. The receptor of Wnt5a is ROR1, whose expression is associated with disease progression and resistance to venetoclax, a BCL-2 inhibitor approved for the treatment of CLL. In this study, we found that the levels of Wnt5a in the plasma of CLL patients were positively correlated with absolute monocyte counts, but not lymphocyte counts. We cultured monocyte-derived nurse-like cells (NLCs) from patients with CLL, and detected Wnt5a expressed in NLCs. Flow cytometry and transwell assays showed that the antibody neutralizing Wnt5a inhibited the enhanced survival and migration in CLL cells co-cultured with NLCs. Furthermore, we performed a drug screening with CLL cells cultured with or without NLCs with a library containing 133 FDA-approved oncology drugs by using high-throughput flow cytometry. We observed a significant resistance to venetoclax in CLL cells co-cultured with NLCs. Immunoblot revealed the activation of NF-κB with enhanced expression of MCL-1 and BCL-XL in CLL cells co-cultured with NLCs. Neutralizing Wnt5a or blocking NF-κB pathway significantly decreased the expression of MCL-1 and BCL-XL, which leads to enhanced sensitivity to venetoclax in CLL cells co-cultured with NLCs. In conclusion, our data showed that NLCs could be one of the sources of Wnt5a detected in patients with CLL, and Wnt5a-induced NF-κB activation in the CLL microenvironment results in resistance to venetoclax in CLL cells.

Cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia: a systematic review of the literature

The continuous improvement of life expectancy of patients with chronic lymphocytic leukemia (CLL) has resulted in increased risk of second primary malignancy that potentially may affect survival and quality of life of CLL patients. We performed a systematic review to assess the risk and the clinical‐pathological features and prognosis of cutaneous squamous cell carcinoma (cSCC) in patients with CLL. We searched PubMed, Embase, and Cochrane Central Register of Control Trials databases for articles published from database inception to December 31, 2019. English‐language studies reporting original data on patients with a specific diagnosis of CLL and cSCC were included. Data were extracted using a standardized extraction form, and any discordance was resolved by consensus. Descriptive data were generated by pooling patients from eligible studies. Of the 4588 non‐duplicate records identified, 55 articles met our inclusion criteria. These studies reported that CLL patients have a 3.2% prevalence of cSCC, with an 11.5% cSCC‐related lethality and an overall risk of metastasis of 5.7% (7.3% for regional lymph node involvement and 3.8% for distant metastasis). The quality of evidence was limited by the high heterogeneity in the design, populations, and objectives of the included studies. This systematic review suggests that cSCC in CLL patients tends to behave less aggressively compared with the solid organ transplant recipients but has a higher morbidity and mortality than in the general population. Future prospective studies are needed to increase the quality of evidence and to determine the best treatment modalities and screening intervals for these patients.

Current and future treatment strategies in chronic lymphocytic leukemia

Treatment decisions for patients with chronic lymphocytic leukemia (CLL) are dependent on symptoms and classification into high-, medium-, or low-risk categories. The prognosis for CLL hinges, in part, on the presence or absence of less-favorable genetic aberrations, including del(17p), del(11q), TP53 dysfunction, and IGHV mutations, as these markers are associated with worse treatment response. Promising results from multiple clinical trials show emerging therapies targeting Burton tyrosine kinase, B-cell leukemia/lymphoma 2, and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta result in better outcomes and prolonged progression-free survival for patients both with and without certain high-risk aberrations. Favorable outcomes using these novel oral targeted therapies, either alone or in combination with other treatments such as anti-CD20 antibodies, has led to their use almost entirely supplanting chemoimmunotherapy in the treatment of CLL. In this narrative review, we summarize the current clinical evidence for the use of targeted mono- and combination therapies for CLL, discuss new and next-generation treatment approaches currently in development, and provide insight into areas of unmet need for the treatment of patients with CLL.