Frontline therapies for untreated chronic lymphoid leukemia

Acalabrutinib in Chinese patients with relapsed/refractory chronic lymphocytic leukemia: Primary analysis from an open-label, multicenter phase 1/2 trial

Acalabrutinib is a highly selective Bruton tyrosine kinase inhibitor approved in the United States and Europe for chronic lymphocytic leukemia (CLL) based on phase 3 trials with limited representation of Asian populations. This phase 1/2 trial evaluates acalabrutinib in Chinese adults with relapsed/refractory (R/R) CLL receiving acalabrutinib 100 mg twice daily in 28-day cycles until disease progression or treatment discontinuation due to adverse events (AEs) presenting substantial clinical risk. The primary endpoint was blinded independent central review (BICR)-assessed overall response rate (ORR). A total of 60 patients from 20 sites in China received acalabrutinib (median age 62 years; median 1 prior therapy line; 21.7% with del(17p) and/or TP53 mutation; 51.7% with unmutated IGHV). Median total treatment duration was 19.4 months (range 0.6-28.2) with 53 patients (88.3%) receiving acalabrutinib at data cutoff; median study follow-up was 20.2 months. BICR-assessed ORR was 85.0% (95% CI, 73.4-92.9). Median duration of response, progression-free survival (PFS), and overall survival (OS) were not reached. Estimated 12-month and 18-month PFS rates were 91.5% (95% CI, 80.9-96.4) and 78.8% (95% CI, 60.9-89.2); OS rates were both 96.7% (95% CI, 87.3-99.2). AEs of grade ≥ 3 occurred in 25 patients (41.7%), most commonly decreased neutrophil count (13.3%, n = 8), pneumonia (6.7%, n = 4), and upper respiratory tract infection (6.7%, n = 4). AEs led to treatment discontinuation in 2 patients (paraneoplastic pemphigus; rectal neoplasm). This study demonstrated high ORR in acalabrutinib-treated Chinese patients with R/R CLL with no unexpected safety concerns. This trial is registered on ClinicalTrials.gov (NCT03932331).

Efficacy and Safety of Bruton Tyrosine Kinase Inhibitor Monotherapy Compared with Combination Therapy for Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma: A Systematic Review and Meta-Analysis

The effectiveness and safety of combination treatments such as chemoimmunotherapies in chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL) remain controversial. Bruton tyrosine kinase inhibitors (BTKis) are an effective therapy for CLL/SLL patients. This meta-analysis aimed to compare the efficacy and safety of BTKis versus combination therapy in CLL/SLL patients. We searched the PubMed, Cochrane, Medline, and Embase databases through February 2023 for relevant randomized controlled trials (RCTs). Four RCTs (including 1510 patients) were found and met the inclusion criteria. Progression-free survival (PFS) was significantly improved with BTKis when compared to the combination therapy (hazard ratio (HR), 0.30; 95% confidence interval (CI), 0.22–0.40), while a pooled analysis of overall survival did not favor single-agent BTKis over the combination therapy (HR, 0.87; 95% CI, 0.67–1.15). We observed consistent benefits for PFS among patients with high-risk disease characteristics. Although there was no difference in complete response between the two arms (risk ratio (RR), 0.54; 95% CI, 0.20–1.46), BTKi use was related to a better overall response rate (RR, 1.10; 95% CI, 1.04–1.16). The risk of grade ≥3 adverse events (AEs) was comparable between the two arms (RR, 0.82; 95% CI, 0.55–1.23). However, the risk of grade ≥3 AEs was significantly lower in the second-generation BTKi group than in the combination therapy group (RR, 0.73; 95% CI, 0.54–0.98). Overall, BTKis have superior efficacy compared to the combination regimens in patients with untreated or treated CLL/SLL without excess toxicity. Further studies are needed to confirm these results and determine the optimal therapy for managing patients with CLL/SLL.

Bruton tyrosine kinase inhibitors in B-cell lymphoma: beyond the antitumour effect

Targeting B-cell receptor signalling using Bruton tyrosine kinase (BTK) inhibitors (BTKis) has become a highly successful treatment modality for B-cell malignancies, especially for chronic lymphocytic leukaemia. However, long-term administration of BTKis can be complicated by adverse on- and/or off-target effects in particular cell types. BTK is widely expressed in cells of haematopoietic origin, which are pivotal components of the tumour microenvironment. BTKis, thus, show broad immunomodulatory effects on various non-B immune cell subsets by inhibiting specific immune receptors, including T-cell receptor and Toll-like receptors. Furthermore, due to the off-target inhibition of other kinases, such as IL-2-inducible T-cell kinase, epidermal growth factor receptor, and the TEC and SRC family kinases, BTKis have additional distinct effects on T cells, natural killer cells, platelets, cardiomyocytes, and other cell types. Such mechanisms of action might contribute to the exceptionally high clinical efficacy as well as the unique profiles of adverse effects, including infections, bleeding, and atrial fibrillation, observed during BTKi administration. However, the immune defects and related infections caused by BTKis have not received sufficient attention in clinical studies till date. The broad involvement of BTK in immunological pathways provides a rationale to combine BTKis with specific immunotherapies, such as immune checkpoint inhibitor or chimeric antigen receptor-T-cell therapy, for the treatment of relapsed or refractory diseases. This review discusses and summarises the above-mentioned issues as a reference for clinicians and researchers.

Pathobiology and Therapeutic Relevance of GSK-3 in Chronic Hematological Malignancies

Glycogen synthase kinase-3 (GSK-3) is an evolutionarily conserved, ubiquitously expressed, multifunctional serine/threonine protein kinase involved in the regulation of a variety of physiological processes. GSK-3 comprises two isoforms (α and β) which were originally discovered in 1980 as enzymes involved in glucose metabolism via inhibitory phosphorylation of glycogen synthase. Differently from other proteins kinases, GSK-3 isoforms are constitutively active in resting cells, and their modulation mainly involves inhibition through upstream regulatory networks. In the early 1990s, GSK-3 isoforms were implicated as key players in cancer cell pathobiology. Active GSK-3 facilitates the destruction of multiple oncogenic proteins which include β-catenin and Master regulator of cell cycle entry and proliferative metabolism (c-Myc). Therefore, GSK-3 was initially considered to be a tumor suppressor. Consistently, GSK-3 is often inactivated in cancer cells through dysregulated upstream signaling pathways. However, over the past 10–15 years, a growing number of studies highlighted that in some cancer settings GSK-3 isoforms inhibit tumor suppressing pathways and therefore act as tumor promoters. In this article, we will discuss the multiple and often enigmatic roles played by GSK-3 isoforms in some chronic hematological malignancies (chronic myelogenous leukemia, chronic lymphocytic leukemia, multiple myeloma, and B-cell non-Hodgkin’s lymphomas) which are among the most common blood cancer cell types. We will also summarize possible novel strategies targeting GSK-3 for innovative therapies of these disorders.

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.

Clinical Trials of the BTK Inhibitors Ibrutinib and Acalabrutinib in Human Diseases Beyond B Cell Malignancies

The BTK inhibitors ibrutinib and acalabrutinib are FDA-approved drugs for the treatment of B cell malignances. Both drugs have demonstrated clinical efficacy and safety profiles superior to chemoimmunotherapy regimens in patients with chronic lymphocytic leukemia. Mounting preclinical and clinical evidence indicates that both ibrutinib and acalabrutinib are versatile and have direct effects on many immune cell subsets as well as other cell types beyond B cells. The versatility and immunomodulatory effects of both drugs have been exploited to expand their therapeutic potential in a wide variety of human diseases. Over 470 clinical trials are currently registered at ClinicalTrials.gov to test the efficacy of ibrutinib or acalabrutinib not only in almost every type of B cell malignancies, but also in hematological malignancies of myeloid cells and T cells, solid tumors, chronic graft versus host disease (cGHVD), autoimmune diseases, allergy and COVID-19 (http:www.clinicaltrials.gov). In this review, we present brief discussions of the clinical trials and relevant key preclinical evidence of ibrutinib and acalabrutinib as monotherapies or as part of combination therapies for the treatment of human diseases beyond B cell malignancies. Adding to the proven efficacy of ibrutinib for cGVHD, preliminary results of clinical trials have shown promising efficacy of ibrutinib or acalabrutinib for certain T cell malignancies, allergies and severe COVID-19. However, both BTK inhibitors have no or limited efficacy for refractory or recurrent solid tumors. These clinical data together with additional pending results from ongoing trials will provide valuable information to guide the design and improvement of future trials, including optimization of combination regimens and dosing sequences as well as better patient stratification and more efficient delivery strategies. Such information will further advance the precise implementation of BTK inhibitors into the clinical toolbox for the treatment of different human diseases.

Cost-effectiveness of a 12-month fixed-duration venetoclax treatment in combination with obinutuzumab in first-line, unfit chronic lymphocytic leukemia in the United States

BACKGROUND: Chronic lymphocytic leukemia (CLL) is a significant health and economic burden in the United States. Treatments include chemoimmunotherapy, such as obinutuzumab (G) plus chlorambucil (Clb) or bendamustine plus rituximab (BR), and chemotherapy-free regimens incorporating oral targeted therapies such as ibrutinib (Ibr), acalabrutinib (Acala), or venetoclax (Ven). Most chemotherapy-free regimens require continuous treatment to progression, while Ven plus G (VenG) is given for a fixed duration of 12 months, based on the CLL14 trial that led to its approval. Fixed-duration VenG has the potential for cost savings compared with treat-to-progression chemotherapy-free regimens. OBJECTIVE: To evaluate the cost-effectiveness of 12 months fixed-duration VenG in first-line treatment of unfit patients with CLL from a US health care payer perspective compared with GClb, BR, Ibr, Ibr + G, Ibr + R, Acala, and Acala + G. METHODS: A partitioned survival model was developed with 3 health states: progression-free survival (PFS), postprogression survival, and dead. The patient population, as based on the CLL14 trial, comprised previously untreated unfit patients with CLL (mean age 71.1 years, 33.1% female). The distribution of patients in each health state over time was estimated using extrapolated PFS and overall survival (OS) curves for VenG and GClb, based on CLL14 data 2 or more years after treatment cessation. PFS and OS for the other comparators were estimated using hazard ratios vs VenG, based on a network metaanalysis. Adverse events, utility values, and costs were obtained from published literature. The model estimated life-years gained, quality-adjusted life-years (QALYs) gained, and costs. The time horizon was 20 years, with a cycle time of 28 days. Outcomes and costs were discounted at 3.0% per year, and costs were estimated from a US health care payer perspective. One-way and probabilistic sensitivity analyses were conducted. RESULTS: In this cross-trial analysis of unfit CLL patients, in the base case, VenG had lower projected total costs than all comparators investigated. VenG also had larger projected health benefits (more QALYs gained) than GClb, BR, Ibr, and Ibr + R. VenG was therefore more effective and less costly than these comparators (dominant). Ibr + G, Acala, and Acala + G showed higher QALYs gained vs VenG (0.022, 0.672, and 0.961, respectively), and substantially higher projected costs vs VenG ($1,488,400, $1,579,737, and $1,656,154, respectively). Thus, Ibr + G, Acala, and Acala + G would cost more than $1,000,000 per QALY gained vs VenG. At the commonly used willingness-to-pay threshold of $150,000 per QALY gained, Ibr + G, Acala, and Acala + G were not cost-effective compared with VenG. CONCLUSIONS: Fixed-duration VenG for 12 months is a cost-effective first-line treatment option for unfit CLL patients compared with other available options and provides value for money to US health care payers at a threshold of $150,000 per QALY gained. Future studies with longer trial follow-up and more mature survival data may help to confirm longer-term cost benefits of VenG. DISCLOSURES: Genentech Inc. and AbbVie provided financial support for this study. Genentech Inc., AbbVie, and Pharmerit - An OPEN Health Company participated in the design, study conduct, analysis, and interpretation of data, as well as the writing, review, and approval of the manuscript. Venetoclax is being developed in a collaboration between Genentech Inc. and AbbVie. Ravelo and Shapouri are employed by Genentech Inc. and have ownership interests. Manzoor and Sail are employed by AbbVie and have ownership interests. Chatterjee, van de Wetering, and Qendri, employees of Pharmerit - An OPEN Health Company, received consultancy fees from AbbVie. Davids has received consultancy fees from AbbVie, AstraZeneca, Eli Lilly, Genentech Inc., Janssen, MEI Pharma, Novartis, Pharmacyclics, and Verastem; research funding from Ascentage Pharma, Genentech Inc., MEI Pharma, Pharmacyclics, Surface Oncology, TG Therapeutics, and Verastem; and has served on board of directors or advisory committees for AbbVie, Adaptive Biotechnologies, AstraZeneca, BeiGene, Eli Lilly, Genentech Inc., Janssen, Pharmacyclics, TG Therapeutics, and Verastem. This study was presented as a poster at ASH 61st Annual Meeting and Exposition; December 7-10, 2019; Orlando, FL.

Multifaceted Immunomodulatory Effects of the BTK Inhibitors Ibrutinib and Acalabrutinib on Different Immune Cell Subsets - Beyond B Lymphocytes

The clinical success of the two BTK inhibitors, ibrutinib and acalabrutinib, represents a major breakthrough in the treatment of chronic lymphocytic leukemia (CLL) and has also revolutionized the treatment options for other B cell malignancies. Increasing evidence indicates that in addition to their direct effects on B lymphocytes, both BTK inhibitors also directly impact the homeostasis, phenotype and function of many other cell subsets of the immune system, which contribute to their high efficacy as well as adverse effects observed in CLL patients. In this review, we attempt to provide an overview on the overlapping and differential effects of ibrutinib and acalabrutinib on specific receptor signaling pathways in different immune cell subsets other than B cells, including T cells, NK cells, monocytes, macrophages, granulocytes, myeloid-derived suppressor cells, dendritic cells, osteoclasts, mast cells and platelets. The shared and distinct effects of ibrutinib versus acalabrutinib are mediated through BTK-dependent and BTK-independent mechanisms, respectively. Such immunomodulatory effects of the two drugs have fueled myriad explorations of their repurposing opportunities for the treatment of a wide variety of other human diseases involving immune dysregulation.

Novel agents and regimens for hematological malignancies: recent updates from 2020 ASH annual meeting

Antibodies and chimeric antigen receptor-engineered T cells (CAR-T) are increasingly used for cancer immunotherapy. Small molecule inhibitors targeting cellular oncoproteins and enzymes such as BCR-ABL, JAK2, Bruton tyrosine kinase, FLT3, BCL-2, IDH1, IDH2, are biomarker-driven chemotherapy-free agents approved for several major hematological malignancies. LOXO-305, asciminib, "off-the-shelf" universal CAR-T cells and BCMA-directed immunotherapeutics as well as data from clinical trials on many novel agents and regimens were updated at the 2020 American Society of Hematology (ASH) Annual Meeting. Major developments and updates for the therapy of hematological malignancies were delineated at the recent Winter Symposium and New York Oncology Forum from the Chinese American Hematologist and Oncologist Network (CAHON.org). This study summarized the latest updates on novel agents and regimens for hematological malignancies from the 2020 ASH annual meeting.

The fading star of obinutuzumab-chlorambucil regimen in patients with comorbidities with chronic lymphocytic leukemia - are we ready for chemo-free immunotherapy approach?

INTRODUCTION

Chronic lymphocytic leukemia (CLL) is the most common leukemia in Western countries occurring typically in elderly patients. These patients often present with comorbidities limiting treatment options. During the last decade, the treatment paradigm has rapidly changed with the introduction of novel oral targeted agents and monoclonal antibodies.

AREAS COVERED

The review focuses on the combination of type II antiCD20 antibody obinutuzumab in combination with chemotherapy or oral targeted agents in patients not suited for fludarabine-based therapy because of comorbidities or age. The main focus of the review is whether classical immunochemotherapy with obinutuzumab-chlorambucil is still a valid therapeutic option or whether the combination of obinutuzumab and ibrutinib or venetoclax presents novel standard of care.

EXPERT OPINION

Both pivotal and registrational studies iLLLUMINATE study testing the combination of ibrutinib and obinutuzumab and CLL14 study testing the fixed combination of venetoclax and obinutuzumab have shown major benefit over chemoimmunotherapy approach in this population. Furthermore, they have excellent activity in high-risk subgroups of CLL paving the road toward a chemo-free immunotherapy approach in this setting. However, there are some pitfalls in these strategies warranting further research.

ASCEND: Phase III, Randomized Trial of Acalabrutinib Versus Idelalisib Plus Rituximab or Bendamustine Plus Rituximab in Relapsed or Refractory Chronic Lymphocytic Leukemia

PURPOSE

Acalabrutinib, a highly selective, potent, Bruton tyrosine kinase inhibitor, was evaluated in this global, multicenter, randomized, open-label, phase III study in patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL).

METHODS

Eligible patients, aged ≥ 18 years with R/R CLL, were randomly assigned 1:1 centrally and stratified by del(17p) status, Eastern Cooperative Oncology Group performance status score, and number of prior lines of therapy. Patients received acalabrutinib monotherapy or investigator's choice (idelalisib plus rituximab [I-R] or bendamustine plus rituximab [B-R]). The primary end point was progression-free survival (PFS) assessed by an independent review committee (IRC) in the intent-to-treat population. Key secondary end points included IRC-assessed overall response rate, overall survival, and safety.

RESULTS

From February 21, 2017, to January 17, 2018, a total of 398 patients were assessed for eligibility; 310 patients were randomly assigned to acalabrutinib monotherapy (n = 155) or investigator's choice (n = 155; I-R, n = 119; B-R, n = 36). Patients had received a median of two prior therapies (range, 1-10). After a median follow-up of 16.1 months (range, 0.03-22.4 months), median PFS was significantly longer with acalabrutinib monotherapy (PFS not reached) compared with investigator's choice (16.5 months [95% CI, 14.0 to 17.1 months]; hazard ratio, 0.31 [95% CI, 0.20 to 0.49]; P < .0001). Estimated 12-month PFS was 88% (95% CI, 81% to 92%) for acalabrutinib and 68% (95% CI, 59% to 75%) for investigator's choice. Serious adverse events occurred in 29% of patients (n = 44 of 154) treated with acalabrutinib monotherapy, 56% (n = 66 of 118) with I-R, and 26% (n = 9 of 35) with B-R. Deaths occurred in 10% (n = 15 of 154), 11% (n = 13 of 118), and 14% (n = 5 of 35) of patients receiving acalabrutinib monotherapy, I-R, and B-R, respectively.

CONCLUSION

Acalabrutinib significantly improved PFS compared with I-R or B-R and has an acceptable safety profile in patients with R/R CLL.

Efficacy and safety of rituximab in autoimmune and microangiopathic hemolytic anemia: a systematic review and meta-analysis

Background

The efficacy and safety of rituximab (RTX) on hemolytic anemia (HA) is unknown. Therefore we retrospectively analyze the efficacy and safety of RTX in autoimmune hemolytic anemia (AIHA) and microangiopathic hemolytic anemia (MAHA) from the previous literature.

Methods

Data in clinical trials and observational studies were collected from PubMed, Cochrane, Embase, and Google Scholar until Oct 15, 2018. The efficacy and safety of RTX in patients with AIHA or MAHA were assessed and overall response rates (ORRs), complete response rates (CRRs), adverse events (AEs) and relapse rates (RRs) were extracted if available. A meta-analysis was performed with a random-effects model, estimating mean proportions in all studies, and relative rates in comparative studies.

Results

After quality assessment, a total of 37 investigations encompassing 1057 patients eligible for meta-analysis were included. Pooled mean proportion of ORR was 0.84 (95% confidence interval [CI] 0.80–0.88), and that of CRR was 0.61 (95% CI 0.49–0.73). Mean AE rate was 0.14 (95% CI 0.10–0.17), and mean RR was 0.21 (95% CI 0.15–0.26). Relative ORR was 1.18 (95% CI 1.02–1.36), and relative CRR was 1.17 (95% CI 0.98–1.39) fold more than the respective non-RTX counter parts. Relative AE rate was 0.77 (95% CI 0.36–1.63), and relative RR was 0.93 (95% CI 0.56–1.55) fold less than the respective non-RTX counter parts.

Conclusion

RTX is more effective than the treatments without RTX for AIHA and MAHA and is well-tolerated.