Lenalidomide and rituximab for the initial treatment of patients with chronic lymphocytic leukemia: a multicenter clinical-translational study from the chronic lymphocytic leukemia research consortium

Maintenance low-dose fixed duration lenalidomide and rituximab following bendamustine and rituximab induction in previously untreated chronic lymphocytic leukemia and small lymphocytic lymphoma

Lenalidomide (LEN) and rituximab (RTX) have independently improved progression-free survival (PFS) in CLL, leading to interest in use of LEN + RTX (R2) following induction chemoimmunotherapy. Patients with previously untreated CLL received bendamustine + RTX (BR) for 6 cycles, then 24 cycles of R2. LEN dosing was 5-10 mg daily; RTX was given odd cycles (12 doses). The primary endpoint is PFS; secondary endpoints are response and overall survival. Thirty-six patients enrolled, median age 64.5 years. Twenty-nine received R2; 12 completed a full course R2 (33.3%), 5 completed R2 with premature discontinuation of LEN. Dose reductions/holds were most often for neutropenia. Complete response was achieved in 33.3%. After median >4 years follow-up, 2-year and 3-year PFS were 86.1% and 69.4%. Five-year overall survival was 92.3%. R2 maintenance may improve PFS after BR induction, and a lower dose of 5 mg/day and ≤1 year of R2 may be most tolerable (NCT00974233).

Long-term follow up of the combination of ofatumumab, high-dose methylprednisolone, and lenalidomide for untreated chronic lymphocytic leukemia with biomarker analysis

BACKGROUND

Advancements in frontline therapy and chemotherapy-sparing treatments in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) have altered the treatment algorithms of this disease. We present a frontline alternative for treatment- naïve (TN) CLL/SLL patients.

METHODS

This was a single-center, phase 2 study of high-dose methylprednisolone (HDMP) and ofatumumab with lenalidomide and ofatumumab consolidative therapy for all comers with TN CLL/SLL. Treatment was continued until disease progression or intolerable side effects. Patients were assessed for response per iwCLL 2008 criteria after completing cycles 3 and 12.

RESULTS

Forty-five patients were enrolled (median age, 62.6 years). High-risk features included del17p (18%), Del11q (22%), and unmutated IGHV gene (76%). Median treatment duration was 32·2 (2·7-75·9) months. Thirty-six patients discontinued treatment due to disease progression (22%), adverse events (40%), allogeneic hematopoietic cell transplantation (allo-HCT) (7%), consent withdrawal (4%), and secondary malignancies (7%). The best overall and complete response rates were 96& and 29% respectively. At median follow-up of 61·7 (5·6-84·9) months, 9 patients remained on treatment. Median progression-free survival was 54·4 (2·9-77·6) months. Three patients underwent allo-HCT after a median of 3 (3-4) treatment cycles. Treatment was well tolerated, with a grade 3/4 infusion reaction in one patient. The most common grade 3/4 hematological adverse event was neutropenia (69%). Four patients had grade 3/4 infections. No grade 3/4 tumor flares, tumor lysis syndrome, or thrombosis were observed.

CONCLUSION

The combination of ofatumumab, HDMP, and lenalidomide was effective and relatively well tolerated in treatment-naive CLL/SLL. Its role in the frontline setting remains unclear given the current available and effective treatment options.

FUNDING

The funders had no role in the study.

Efficacy and safety of add-on anti-CD20 monoclonal antibody to Bruton tyrosine kinase inhibitor treatment for chronic lymphocytic leukemia: a meta-analysis

The efficacy of Bruton tyrosine kinase inhibitors (BTKi) remains suboptimal in chronic lymphocytic leukemia (CLL) treatment. A systematic review and meta-analysis were conducted to compare the outcomes of combining anti-CD20 monoclonal antibodies (mAb) with BTKi therapy versus BTKi monotherapy for patients with CLL. We searched for relevant studies in the Pubmed, Medline, Embase, and Cochrane databases until December 2022. We estimated the effective results using a hazard ratio (HR) for survival outcomes and relative risk (RR) for response outcomes and safety. Four randomized controlled trials (including 1056 patients) were found until November 2022 and fulfilled the inclusion criteria. Progression-free survival was significantly improved with the addition of anti-CD20 mAb to BTKi over BTKi (HR 0.70, 95% confidence interval (CI) 0.51-0.97), whereas pooled analysis of overall survival did not favor combination therapy compared to BTKi monotherapy (HR 0.72, 95% CI 0.50-1.04). Combination therapy was related to a statistically better complete response (RR, 2.03; 95% CI 1.01 to 4.06) and an undetectable minimal residual disease rate (RR, 6.43; 95% CI 3.54 to 11.67). The risk of grade ≥ 3 adverse events was comparable between the two groups (RR, 1.08; (95% CI 0.80 to 1.45). Overall, adding anti-CD20 mAb to BTKi revealed superior efficacy than BTKi alone in untreated or previously treated CLL patients without affecting the safety of single-agent BTKi. Conducting further randomized studies to confirm our results and determine the optimal therapy for managing patients with CLL is essential.

Immunomodulatory Drugs for the Treatment of B Cell Malignancies

Accumulating evidence suggests that the tumor microenvironment (TME) is involved in disease progression and drug resistance in B cell malignancies, by supporting tumor growth and facilitating the ability of malignant cells to avoid immune recognition. Immunomodulatory drugs (IMiDs) such as lenalidomide have some direct anti-tumor activity, but critically also target various cellular compartments of the TME including T cells, NK cells, and stromal cells, which interfere with pro-tumor signaling while activating anti-tumor immune responses. Lenalidomide has delivered favorable clinical outcomes as a single-agent, and in combination therapy leads to durable responses in chronic lymphocytic leukemia (CLL) and several non-Hodgkin lymphomas (NHLs) including follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL), and mantle cell lymphoma (MCL). Recently, avadomide, a next generation cereblon E3 ligase modulator (CELMoD), has shown potent anti-tumor and TME immunomodulatory effects, as well as promising clinical efficacy in DLBCL. This review describes how the pleiotropic effects of IMiDs and CELMoDs could make them excellent candidates for combination therapy in the immuno-oncology era-a concept supported by preclinical data, as well as the recent approval of lenalidomide in combination with rituximab for the treatment of relapsed/refractory (R/R) FL.

[Clinical analysis of fludarabine and cyclophosphamide combined with rituximab in the first-line treatment of 43 cases of chronic lymphoblastic leukemia]

目的

探讨FCR方案（氟达拉滨+环磷酰胺+利妥昔单抗）一线治疗慢性淋巴细胞白血病（CLL）的疗效。

方法

回顾性分析2004年5月至2017年12月一线应用FCR方案治疗的43例CLL患者的临床资料。

结果

①43例CLL患者中，男31例，女12例，接受FCR方案治疗时中位年龄58（36～72）岁；8例患者伴B症状，外周血中位淋巴细胞计数26（3～550）×10⁹/L，IGHV基因未突变62.1％（18/29），P53基因缺失14.0％（6/43），RB1基因缺失18.6％（8/43），12号染色体三体占25.6％（11/33），ATM基因缺失16.7％（7/42）。全部患者FCR方案中位疗程数为4（2～6）个。②全部43例患者的总体反应率（ORR）为88.4％（38/43），完全缓解（CR）20例（46.5％），部分缓解（PR）18例（41.9％），疾病稳定（SD）4例（9.3％），疾病进展（PD）1例（2.3％）；7例（16.3％）患者获得微小残留病（MRD）阴性。③中位随访51（6～167）个月，中位无进展生存（PFS）时间为67（29～105）个月，中位总生存（OS）时间未达到，5年PFS率为（62.1±8.6）％，10年PFS率为（31.0±14.3）％，5年OS率为（70.5±8.3）％，10年OS率为（51.3±13.8）％。疗程数<4为影响OS的不良预后因素，P53基因缺失、疗程数<4为影响PFS的不良预后因素（P<0.001），且在多因素分析中仍具有预后意义［P53基因缺失：HR＝7.65（95％CI 1.74～33.60），P＝0.007；疗程数<4：HR＝3.75（95％CI 1.19～11.80），P＝0.025］。④18例（41.9％）患者于化疗后发生2～3级感染，19例（44.2％）发生3～4级血液学不良反应，1例（2.3％）患者发生肿瘤溶解综合征，所有不良反应经对症处理均恢复。

结论

FCR方案一线治疗CLL的治疗反应及远期生存较理想，不良反应可接受。

Immune Dysfunctions and Immune-Based Therapeutic Interventions in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy characterized by a wide range of tumor-induced alterations, which affect both the innate and adaptive arms of the immune response, and accumulate during disease progression. In recent years, the development of targeted therapies, such as the B-cell receptor signaling inhibitors and the Bcl-2 protein inhibitor venetoclax, has dramatically changed the treatment landscape of CLL. Despite their remarkable anti-tumor activity, targeted agents have some limitations, which include the development of drug resistance mechanisms and the inferior efficacy observed in high-risk patients. Therefore, additional treatments are necessary to obtain deeper responses and overcome drug resistance. Allogeneic hematopoietic stem cell transplantation (HSCT), which exploits immune-mediated graft-versus-leukemia effect to eradicate tumor cells, currently represents the only potentially curative therapeutic option for CLL patients. However, due to its potential toxicities, HSCT can be offered only to a restricted number of younger and fit patients. The growing understanding of the complex interplay between tumor cells and the immune system, which is responsible for immune escape mechanisms and tumor progression, has paved the way for the development of novel immune-based strategies. Despite promising preclinical observations, results from pilot clinical studies exploring the safety and efficacy of novel immune-based therapies have been sometimes suboptimal in terms of long-term tumor control. Therefore, further advances to improve their efficacy are needed. In this context, possible approaches include an earlier timing of immunotherapy within the treatment sequencing, as well as the possibility to improve the efficacy of immunotherapeutic agents by administering them in combination with other anti-tumor drugs. In this review, we will provide a comprehensive overview of main immune defects affecting patients with CLL, also describing the complex networks leading to immune evasion and tumor progression. From the therapeutic standpoint, we will go through the evolution of immune-based therapeutic approaches over time, including i) agents with broad immunomodulatory effects, such as immunomodulatory drugs, ii) currently approved and next-generation monoclonal antibodies, and iii) immunotherapeutic strategies aiming at activating or administering immune effector cells specifically targeting leukemic cells (e.g. bi-or tri-specific antibodies, tumor vaccines, chimeric antigen receptor T cells, and checkpoint inhibitors).

Frontline Therapy of Chronic Lymphocytic Leukemia: Changing Treatment Paradigm

PURPOSE OF REVIEW

The treatment landscape of treatment-naive chronic lymphocytic leukemia (TN-CLL) is rapidly evolving. As more and more new drugs and combinations are becoming part of therapeutic armamentarium, it becomes highly pertinent to understand the evidence for each of the treatment options to select the right drug for the right patient. We summarize the recent data of the available frontline treatment options.

RECENT FINDINGS

The novel agents can overcome adverse biological attributes and provide long-term disease control. MRD may become a reliable surrogate for survival in the evaluation of future therapies. FCR still remains one of the best options in a young fit CLL with mutated IGVH. Long-term follow-up data of ibrutinib confirm its efficacy and safety in both high-risk and elderly TN-CLL patients. A combination of venetoclax with obinutuzumab has provided the hope of fixed-duration therapy and the potential for functional cure in TN-CLL. Several other trials testing the efficacy of other targeted agents and the optimal sequencing approaches are underway. Chemoimmunotherapy holds its ground as an effective treatment in the IGVH-mutated CLL. The targeted agents either singly or in combination have become standard of care in many subsets of TN-CLL.

Efficacy and predictors of response of lenalidomide and rituximab in patients with treatment-naive and relapsed CLL

This phase 2 study was conducted to prospectively evaluate how clinical and biological factors correlate with outcome in patients with treatment-naive (TN) and relapsed (R) chronic lymphocytic leukemia (CLL) treated with lenalidomide and rituximab. Oral lenalidomide 10 mg was administered daily starting on day 9 of cycle 1. IV rituximab 375 mg/m² was administered weekly during cycle 1 and every 4 weeks for cycles 3 to 12. Sequencing of a custom panel of 295 genes was performed in pretreatment bone marrow samples. The study included 61 patients with TN CLL and 59 with R CLL; the overall response rate (ORR) was 73% and 64%, respectively. A baseline β₂-microglobulin level <4 mg/L was associated with higher ORR in both groups (both, P = .03), and absence of mutations in the NOTCH signaling pathway showed a trend for association with higher ORR in R CLL (P = .10). Median PFS was 50 months in TN patients and 28 months in R patients. On multivariate analysis, age ≥65 years (P = .02) was associated with shorter PFS in TN patients, whereas according to univariate analysis, >2 previous therapies (P = .02) was the only factor associated with shorter PFS in R patients. A trend for association between mutations in the NOTCH pathway and shorter PFS was observed in TN CLL (P = .15). Further exploration of the NOTCH pathway may help optimize the efficacy of this combination in patients with CLL. This study protocol was approved by the University of Texas MD Anderson Cancer Center institutional review board and registered at clinicaltrials.gov (#NCT01446133).

Evolution in the management of chronic lymphocytic leukemia in Japan: should MRD negativity be the goal?

Advances in the molecular biology of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and development of molecularly targeted therapies have resulted in treatment innovations. Therapeutic approaches for previously untreated CLL/SLL patients are changing from chemoimmunotherapy (CIT) to molecularly targeted drugs. The aim of therapy for CLL patients has been to control the disease; however, FCR (fludarabine, cyclophosphamide, rituximab) has improved outcomes and reduced the high incidence of undetectable minimum/measurable residual disease (MRD) in previously untreated CLL patients with no 17p deletion/TP53 disruption and mutated immunoglobulin heavy chain gene (IGHV). Patients achieving undetectable MRD in the bone marrow are expected to be cured. BTK inhibitors and BCL-2 inhibitors are effective for CLL/SLL patients. However, atrial fibrillation and bleeding are associated with the BTK inhibitor, ibrutinib, while tumor lysis syndrome is an adverse event (AE) of the BCL-2 inhibitor, venetoclax. Although these novel targeted drugs are very useful, they are also expensive. Emergence of resistant clones of CLL cells must also be addressed. Therefore, treatments of indefinite duration until progression have been replaced by fixed-duration treatments. This review introduces advances in the treatment of previously untreated CLL/SLL patients in Europe and the United States.

Targeted Therapies in CLL: Monotherapy Versus Combination Approaches

PURPOSE OF REVIEW

While chemoimmunotherapy has improved outcomes in chronic lymphocytic leukemia (CLL), it is not curative, has significant relapse rates, and is not always well tolerated. Recently, novel targeted therapies have been developed to increase response rates and reduce toxicity, especially in high-risk disease. Current goals of CLL therapies are to produce deep and durable, especially minimal residual disease (MRD)-negative, remissions so as to allow patients to ultimately discontinue treatment for a while. Whether this can be achieved with single agents or combination regimens is being investigated. Here, we comment on what the results of recent and ongoing clinical trials mean for the future of CLL therapy.

RECENT FINDINGS

Large trials have proven the efficacy of novel therapies including small-molecule inhibitors like ibrutinib, idelalisib, and venetoclax. These agents are approved as monotherapy for first-line treatment and/or in the relapsed/refractory setting. However, it appears that combining these drugs with other novel agents or with chemoimmunotherapy can give higher rates of MRD-negative remission, and delay disease resistance. Chimeric antigen receptor-T cells may change the outlook for patients with heavily refractory CLL. Further research will determine which drug combinations are optimal for the various subgroups of CLL patients.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

Feasibility and efficacy of addition of individualized-dose lenalidomide to chlorambucil and rituximab as first-line treatment in elderly and FCR-unfit patients with advanced chronic lymphocytic leukemia

Lenalidomide has been proven to be effective but with a distinct and difficult to manage toxicity profile in the context of chronic lymphocytic leukemia, potentially hampering combination treatment with this drug. We conducted a phase 1-2 study to evaluate the efficacy and safety of six cycles of chlorambucil (7 mg/m² daily), rituximab (375 mg/m² cycle 1 and 500 mg/m² cycles 2-6) and individually-dosed lenalidomide (escalated from 2.5 mg to 10 mg) (induction-I) in first-line treatment of patients with chronic lymphocytic leukemia unfit for treatment with fludarabine, cyclophosphamide and rituximab. This was followed by 6 months of 10 mg lenalidomide monotherapy (induction-II). Of 53 evaluable patients in phase 2 of the study, 47 (89%) completed induction-I and 36 (68%) completed induction-II. In an intention-to-treat analysis, the overall response rate was 83%. The median progression-free survival was 49 months, after a median follow-up time of 27 months. The 2- and 3-year progression-free survival rates were 58% and 54%, respectively. The corresponding rates for overall survival were 98% and 95%. No tumor lysis syndrome was observed, while tumor flair reaction occurred in five patients (9%, 1 grade 3). The most common hematologic toxicity was grade 3-4 neutropenia, which occurred in 73% of the patients. In conclusion, addition of lenalidomide to a chemotherapy backbone followed by a fixed duration of lenalidomide monotherapy resulted in high remission rates and progression-free survival rates, which seem comparable to those observed with novel drug combinations including novel CD20 monoclonal antibodies or kinase inhibitors. Although lenalidomide-specific toxicity remains a concern, an individualized dose-escalation schedule is feasible and results in an acceptable toxicity profile. EuraCT number: 2010-022294-34.

Activation of Th1 Immunity within the Tumor Microenvironment Is Associated with Clinical Response to Lenalidomide in Chronic Lymphocytic Leukemia

Immune stimulation contributes to lenalidomide's antitumor activity. Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of mature, autoreactive B cells in secondary lymphoid tissues, blood, and bone marrow and progressive immune dysfunction. Previous studies in CLL indicated that lenalidomide can repair defective T cell function in vitro. Whether T cell activation is required for clinical response to lenalidomide remains unclear. In this study, we report changes in the immune microenvironment in patients with CLL treated with single-agent lenalidomide and associate the immunologic effects of lenalidomide with antitumor response. Within days of starting lenalidomide, T cells increased in the tumor microenvironment and showed Th1-type polarization. Gene expression profiling of pretreatment and on-treatment lymph node biopsy specimens revealed upregulation of IFN-γ and many of its target genes in response to lenalidomide. The IFN-γ-mediated Th1 response was limited to patients achieving a clinical response defined by a reduction in lymphadenopathy. Deep sequencing of TCR genes revealed decreasing diversity of the T cell repertoire and an expansion of select clonotypes in responders. To validate our observations, we stimulated T cells and CLL cells with lenalidomide in culture and detected lenalidomide-dependent increases in T cell proliferation. Taken together, our data demonstrate that lenalidomide induced Th1 immunity in the lymph node that is associated with clinical response.

Venous thromboembolism in patients with non-Hodgkin lymphoma or chronic lymphocytic leukemia treated with lenalidomide: a systematic review

Lenalidomide has been associated with an increased risk of venous thromboembolism (VTE) in multiple myeloma. It is unclear whether patients with non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) are also at such risk. We conducted a systematic review of the incidence of VTE in prospective trials of lenalidomide-treated patients with NHL or CLL. Sixty-eight unique reports were assessed for inclusion. For grade ≥3 VTE, 98 events were reported in 3043 patients (60 studies) (crude incidence: 3.22% [95% confidence interval: 2.6-3.9%]). For any grade VTE, 97 events were reported in 2244 patients (46 studies) (crude incidence: 4.32% [3.5-5.2%]). Subgroup analysis showed no difference based on histological subtype or use of prophylaxis. The study is at risk of bias, largely due to insufficient data from the individual studies. Within the limitations of this systematic review, we found a low risk of VTE in patients with NHL treated with lenalidomide.

Optimizing frontline therapy of CLL based on clinical and biological factors

The heterogeneity of the clinical course of chronic lymphocytic leukemia (CLL) ranges from an indolent course, where patients do not require therapy for many years, to a very aggressive disease, where treatment is required soon after diagnosis and relapses may occur early. The improved tools for prognostication allow predicting the outcome of patients with increasing reliability. Some markers also allow selecting more specific therapies with improved activity in the presence of certain genetic or clinical features of CLL. Of these markers, TP53 dysfunction, age, the presence of comorbidities and the immunoglobulin heavy-chain variable region gene mutational status, or serum markers such as β2-microglobulin have shown independent prognostic value in multiple prospective trials. During the last 10 years, multiple novel agents have become available. The advent of oral kinase inhibitors or Bcl-2 antagonists has provided highly effective options with acceptable toxicity. This manuscript summarizes the current evidence of the available treatment options and proposes an integrated algorithm for the frontline therapy of CLL.

What Is Optimal Front-Line Therapy for Chronic Lymphocytic Leukemia in 2017?

OPINION STATEMENT

The front-line management of patients with chronic lymphocytic leukemia (CLL) has evolved significantly in recent years due to introduction of novel, targeted agents. Upon CLL diagnosis, physicians should determine whether treatment or careful observation is indicated. Once treatment is required, choice of therapy should be based on the age and fitness of the patient and the distinct molecular profile of their disease. As multiple novel agents are in various stages of development, all patients regardless of their age, fitness, and disease risk should be evaluated for clinical trial participation before initiating any front-line therapy. If no clinical trial is available, we provide our recommendations for front-line treatment of CLL patients. Healthy, young patients with low-risk disease (mutated IgVH, del (13q)) should be offered fludarabine, chlorambucil, and rituximab (FCR), while similar patients with high-risk disease (unmutated IgVH, del (17p), del (11q), and complex karyotype) should be considered for ibrutinib therapy. For those young, fit patients with high-risk disease and a contraindication to ibrutinib, FCR, or high-dose methylprednisolone and rituximab are options. In regard to older, unfit patients, a careful assessment of their fitness and ability to tolerate treatment should be undertaken before starting therapy. Those who have poor performance and multiple medical comorbidities should be considered for palliative care alone. However, those who are fit enough for treatment can be offered ibrutinib. If there is a contraindication to ibrutinib, they can be separated into low- and high-risk molecular groups. For the low-risk patients, bendamustine and rituximab or obinutuzumab and chlorambucil can be considered. For the high-risk patients, treatment with rituximab and lenalidomide is an option. Herein, we provide an evidence-based front-line treatment algorithm for CLL patients based upon fitness and molecular risk.

Increased SHISA3 expression characterizes chronic lymphocytic leukemia patients sensitive to lenalidomide

Lenalidomide is a therapeutically effective drug in chronic lymphocytic leukemia (CLL). Twenty-seven CLL patients were treated with lenalidomide in a phase II clinical trial. Ten patients were grouped as responders (R) and 6 as nonresponders (NR). We evaluated T lymphocytes, NK, monocytes and dendritic cells at baseline and after treatment. A gene expression analysis was performed on 16 CLL samples collected before treatment. The levels of immune cells or immune-related cytokines are not different between R and NR patients. However, CLL patients sensitive to lenalidomide clearly show a peculiar gene expression profile in leukemic cells. The most up-regulated gene (fold change =  +23 in R vs. NR) is Wnt inhibitor SHISA homolog 3 (SHISA3). SHISA3^highCLL are characterized by a restrained activation of Wnt signaling and sensibility to lenalidomide-induced apoptosis. In conclusion, SHISA3 is a candidate gene for the identification of CLL patients who will benefit of lenalidomide treatment as single agent.

Pharmacotherapy of relapsed/refractory chronic lymphocytic leukemia

INTRODUCTION

The treatment of relapsed/refractory (RR) CLL has been revolutionized by the advent of the new oral inhibitors of B-cell receptor (BCR) signaling and the pro-survival protein, B-cell lymphoma 2 (BCL2). Additionally, new and more potent monoclonal antibodies against CD20 have replaced/may replace rituximab in many settings. Areas covered: Herein, we review the entire therapeutic landscape of RR CLL, with particular attention to the new small-molecule kinase inhibitors and BH3-mimetics. We discuss preclinical data with these agents in CLL, cover available efficacy and safety information, and examine potential resistance mechanisms and possible rational combinations to circumvent them. Expert opinion: The availability of potent and selective inhibitors of BCR signaling and of the anti-apoptotic functions of BCL2 has enormously enhanced our therapeutic armamentarium, with unprecedented efficacy now observed in patients who historically had poor outcomes with chemoimmunotherapy (CIT), e.g., those with deletion 17p/11q and/or IGHV-unmutated disease. The next challenge is to optimally sequence these agents and develop rational combinations that will hopefully lead to deeper and more durable remissions than ever seen before. Indeed, long term relapse free survival, already achievable with CIT in patients with genetically favorable-risk disease, now appears to be a realistic possibility for most patients with CLL.

Lenalidomide in the treatment of chronic lymphocytic leukemia

INTRODUCTION

Lenalidomide is an immunomodulatory drug (IMiD) with a unique mode of action (MOA) that may vary across disease-type. It is currently approved in multiple myeloma (MM), myelodysplastic syndrome (MDS) and mantle cell lymphoma (MCL), yet is also clinically active in a host of lymphoproliferative diseases, including chronic lymphocytic leukemia (CLL). Due to its protean effects on the immune system, lenalidomide may be particularly appealing in CLL, which is distinct in its ability to evade immune recognition and cause immunosuppression. Areas covered: This review recaps the biological mechanisms of lenalidomide specific for CLL, and summarizes the clinical data in previously untreated and relapsed/refractory (R/R) CLL patients, with emphasis on toxicity. Moreover, lenalidomide treatment is put into the context of the highly effective targeted agents that are drastically changing the therapeutic approach in CLL. Expert opinion: Lenalidomide is a potent drug in CLL, both in first line and relapse. However, in comparison to other newly available agents, lenalidomide has slow onset of efficacy and notable toxicity profile that limits both its single agent use and combinations with chemotherapy. Future trials will hopefully direct our ability to harness lenalidomide MOA to best incorporate it in the rapidly evolving landscape of CLL treatment.

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a malignancy of CD5+ B cells that is characterized by the accumulation of small, mature-appearing lymphocytes in the blood, marrow and lymphoid tissues. Signalling via surface immunoglobulin, which constitutes the major part of the B cell receptor, and several genetic alterations play a part in CLL pathogenesis, in addition to interactions between CLL cells and other cell types, such as stromal cells, T cells and nurse-like cells in the lymph nodes. The clinical progression of CLL is heterogeneous and ranges from patients who require treatment soon after diagnosis to others who do not require therapy for many years, if at all. Several factors, including the immunoglobulin heavy-chain variable region gene (IGHV) mutational status, genomic changes, patient age and the presence of comorbidities, should be considered when defining the optimal management strategies, which include chemotherapy, chemoimmunotherapy and/or drugs targeting B cell receptor signalling or inhibitors of apoptosis, such as BCL-2. Research on the biology of CLL has profoundly enhanced our ability to identify patients who are at higher risk for disease progression and our capacity to treat patients with drugs that selectively target distinctive phenotypic or physiological features of CLL. How these and other advances have shaped our current understanding and treatment of patients with CLL is the subject of this Primer.

The safety profile of monoclonal antibodies for chronic lymphocytic leukemia

INTRODUCTION

Monoclonal antibodies (MoAbs), non-chemotherapeutic agents targeting the antigens present on chronic lymphocytic leukemia (CLL) lymphocytes, are being implemented increasingly more often as treatment options. Areas covered: This article reviews the similarities and differences in the structure, mechanism of action, efficacy and safety profile of commercially-available MoAbs and prevents new agents potentially useful for CLL treatment. Publications in English before June 2016 were surveyed on the MEDLINE database for articles. Proceedings of the American Society of Hematology held during the last five years were also included. Expert opinion: MoAbs, especially those targeting CD20, are highly effective biological options for first-line and salvage treatment of CLL, particularly in chemoimmunotherapy, and possibly also as maintenance therapy. Treatment with MoAbs is associated with reduced risk of such adverse events as cytopenias, infections and secondary neoplasias and is generally well tolerated. Depending on antibody type, the most common adverse events are usually transient and limited to grade 1 and 2 infusion-related reactions. In addition to commercially available MoAbs, several other antibodies exist which are targeted against different antigens studied in the clinical trials.

The biology behind B-cell lymphoma 2 as a target in chronic lymphocytic leukemia

B-cell lymphoma 2 (BCL2)-type proteins are key regulators of the intrinsic or mitochondrial pathway for apoptosis. Since escape from apoptosis is one the main 'hallmarks of cancer', BCL2 inhibitors have emerged as promising therapeutic agents for diverse lymphoid malignancies, particularly chronic lymphocytic leukemia (CLL). Multiple clinical trials have shown efficacy of these agents in patients with relapsed/refractory disease with a favorable toxicity profile. Moreover, some clinical trials indicate that combination with monoclonal antibodies and other novel agents may enhance their effect.

Mobilization of human immature hematopoietic progenitors through combinatory use of bortezomib and immunomodulatory drugs

Combination use of the proteasome inhibitor bortezomib and the immunomodulatory drugs lenalidomide or thalidomide has provided superior outcomes in multiple myeloma over their single use; however, these combinations can produce significant toxicities. Unexpectedly, we found a small but significant increase in the population of immature granulocytes and erythrocytes/megakaryocytes in peripheral blood in 16 of 22 patients (73%) treated with dexamethasone in combination with bortezomib and immunomodulatory drugs (triplet), but not in any of 25 patients treated with either bortezomib or immunomodulatory drugs with dexamethasone (doublet). These immature cells gradually increased to a peak level (mean 2.6% per white blood cells) with triplet therapy, and disappeared immediately after therapy cessation. The numbers of circulating CD34⁺ cells and colony-forming cells derived from peripheral blood mononuclear cells increased after triplet therapy compared with those in patients treated by either bortezomib or immunomodulatory drugs plus dexamethasone. Furthermore, triplet regimen downregulated the expression of CXCR4, a chemokine receptor essential for bone marrow retention, on CD34⁺ cells, suggesting an unexpected effect on normal hematopoietic stem/progenitor cells through the reduced interaction with the bone marrow microenvironment. Our observations suggest that combination use should be carefully evaluated to exert synergistic anti-myeloma effects while avoiding unexpected adverse events.

Phase I-II study of lenalidomide and alemtuzumab in refractory chronic lymphocytic leukemia (CLL): effects on T cells and immune checkpoints

This phase I–II study explored safety, immunomodulatory and clinical effects of lenalidomide (weeks 1–16) and alemtuzumab (weeks 5–16) in 23 patients with refractory chronic lymphocytic leukemia. Most patients had Rai stage III/IV disease and were heavily pretreated (median 4 prior therapies), and 61% had del(17p)/del(11q). Eleven of 19 evaluable patients (58%) responded, with a median response duration of 12 months (1–29+); time to progression was short in non-responders. Lenalidomide had a narrow therapeutic dose range, 2.5 mg/day was not efficient, and maximum tolerated dose was 5 mg/day. Grade 3–4 neutropenia and thrombocytopenia occurred in 84 and 55%, 30% had febrile neutropenia, and CMV-reactivation requiring valganciclovir occurred in 30% of patients. The frequency of proliferating (Ki67⁺) CD8⁺ T cells was increased at week 4, with further increase in both the CD4⁺ and CD8⁺ subsets (p < 0.01 and <0.05), which was accompanied by significant upregulation of HLA-DR after addition of alemtuzumab. Antigen-experienced cells increased at week 4 as the frequency of effector memory cells increased in the CD8⁺ subset (p < 0.003), while effector cells decreased in both the CD8⁺ and CD4⁺ subsets (p < 0.0001 and p < 0.01). The Th1/Th2 balance was unchanged at week 4 but shifted toward a Th2 profile after combination therapy. At end of treatment, the frequency of Th17 and regulatory T cells was reduced (p < 0.01), naïve T cells decreased, and effector memory T cells increased (p < 0.05 and p < 0.01). Granzyme B⁺ T cells increased at 30-week follow-up (p < 0.05). PD-1 expression was unaffected. In conclusion, low-dose lenalidomide and alemtuzumab induced major perturbations of T cells, including increased proliferative activity and cytotoxic potential.

Management of Chronic Lymphocytic Leukemia in the Elderly

BACKGROUND

Because chronic lymphocytic leukemia (CLL) typically follows an indolent course, many patients do not need to initiate therapy until they reach a relatively advanced age, when frailty and reduced organ function can make some of the standard treatments difficult to tolerate and less effective. However, recent advances in the understanding of CLL biology and the approval of agents in novel treatment classes have offered significant advances in the management of the disease.

METHODS

The author reviewed current treatment goals in CLL management, including issues surrounding complete remission (CR) and minimal residual disease (MRD); the findings of trials of treatments from novel drug classes, primarily kinase inhibitors and monoclonal antibodies; and current strategies for use of standard and novel therapies for treatment of individuals diagnosed with CLL, particularly elderly patients.

RESULTS

Several agents and regimens featuring improved clinical outcomes and tolerability are now available or in advanced development for the management of CLL patients, including the elderly and those with high-risk disease. These include ibrutinib, idelalisib plus rituximab, and obinutuzumab plus chlorambucil.

CONCLUSION

The availability of Bruton's tyrosine kinase inhibitors and phosphatidylinositol 3-kinase inhibitors and other novel therapies will allow elderly CLL patients to receive more efficacious treatment with greater tolerability than available with traditional approaches for management of the disease.

Low dose of lenalidmide and PI3K/mTOR inhibitor trigger synergistic cytoxicity in activated B cell-like subtype of diffuse large B cell lymphoma

Background

Activated B cell-like subtype of diffuse large B cell lymphoma (ABC-DLBCL) presents aggressive clinical courses and poor prognosis. Targeting key pathways may raise the possibility of improving clinical outcomes.

Methods

The synergetic effects were assessed by CCK-8 assay and measured by isobologram analysis. The NVP-Bez235 and lenalidomide cytotoxicity were measured by flow cytometry, Western Blot and si-RNA transfection. The combined treatment inducing tumor regression in vivo was performed in nude mice of OCI-Ly10 xenograft mouse model.

Results

Low dose of two agents represented significant inhibition of proliferation with CI value < 1. NVP-Bez235 combined with lenalidomide remarkably increased apoptosis through intrinsic pathway by upregulating Bim, Bax and downregulating Bcl-xL. Akt, especially NF-κB, played an important role in the synergetic effects. Cotreatment also induced the cell cycle to be arrested in G0/G1 phase, and decreased S phase by increasing p21 expression, downregulating cyclinA and diminishing CDK2 phosphorylation in Su-DHL2 and OCI-Ly3 but not in OCI-Ly10. Mice treated with NVP-Bez235/lenalidomide represented obvious tumor growth regression and prolonged overall survival.

Conclusions

Our findings demonstrated the synergistic effect of low dose of NVP-Bez235 and lenalidomide in ABC-DLBCL, the underlying mechanism may be multifunctional, involving apoptosis, Akt and NF-κB inactivation and cell cycle arrest. Cotreatment was also effective in vivo. These data pave the way for potential treatment of ABC-DLBCL with combination of NVP-Bez235 and lenalidomide.

Chronic lymphocytic leukemia (CLL)-Then and now

The field of chronic lymphocytic leukemia (CLL) has witnessed considerable change since the time clinical staging was introduced in clinical practice in 1975. Over the years, the prognostication in CLL has expanded with the addition in late 90s of mutational status of variable region of immunoglobulin heavy chain (IGHV), and chromosomal analyses using fluorescent in situ hybridization (FISH). More recently, stereotypy of BCR (B cell receptor) and whole exome sequencing (WES) based discovery of specific mutations such as NOTCH1, TP53, SF3B1, XPO-1, BIRC3, ATM, and RPS15 further refined the current prognostication system in CLL. In therapy, the field of CLL has seen major changes from oral chlorambucil and steroids prior to 1980s, to chemo-immunotherapy (CIT) with fludarabine, cyclophosphamide, rituximab (FCR) to the orally administered targeted therapeutic agents inhibiting kinases in the B cell receptor (BCR) signaling pathway such as Ibrutinib (BTK inhibitor) and Idelalisib (p110 PI3Kδ inhibitor) and novel anti-CD20 mAb's (monoclonal antibodies) such as obinutuzumab. This progress is continuing and other targeted therapeutics such as Bcl2 antagonists (Venetoclax or ABT-199) and finally chimeric antigen receptor against T cells (CART) are in the process of being developed. This review is an attempt to summarize the major benchmarks in the prognostication and in the therapy of CLL. The topic allocated to us by Dr Ayalew Tefferi and Dr Carlo Brugnara is very appropriate to reminisce what our understanding of chronic lymphocytic leukemia (CLL) was in 1976 and how rapidly have the advances occurring in this field affected the patients with CLL.

The chronic lymphocytic leukemia microenvironment: Beyond the B-cell receptor

Malignant B cells accumulate in the peripheral blood, bone marrow, and lymphoid organs of patients with chronic lymphocytic leukemia (CLL). In the tissue compartments, CLL shape a protective microenvironment by coopting normal elements. The efficacy of drugs that target these interactions further underscores their importance in the pathogenesis of CLL. While the B cell receptor (BCR) pathway clearly plays a central role in the CLL microenvironment, there is also rationale to evaluate agents that inhibit other aspects or modulate the immune cells in the microenvironment. Here we review the main cellular components, soluble factors, and signaling pathways of the CLL microenvironment, and highlight recent clinical advances. As the BCR pathway is reviewed elsewhere, we focus on other aspects of the microenvironment.

Microenvironment interactions and B-cell receptor signaling in Chronic Lymphocytic Leukemia: Implications for disease pathogenesis and treatment

Chronic Lymphocytic Leukemia (CLL) is a malignancy of mature B lymphocytes which are highly dependent on interactions with the tissue microenvironment for their survival and proliferation. Critical components of the microenvironment are monocyte-derived nurselike cells (NLCs), mesenchymal stromal cells, T cells and NK cells, which communicate with CLL cells through a complex network of adhesion molecules, chemokine receptors, tumor necrosis factor (TNF) family members, and soluble factors. (Auto-) antigens and/or autonomous mechanisms activate the B-cell receptor (BCR) and its downstream signaling cascade in secondary lymphatic tissues, playing a central pathogenetic role in CLL. Novel small molecule inhibitors, including the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib and the phosphoinositide-3-kinase delta (PI3Kδ) inhibitor idelalisib, target BCR signaling and have become the most successful new therapeutics in this disease. We here review the cellular and molecular characteristics of CLL cells, and discuss the cellular components and key pathways involved in the cross-talk with their microenvironment. We also highlight the relevant novel treatment strategies, focusing on immunomodulatory agents and BCR signaling inhibitors and how these treatments disrupt CLL-microenvironment interactions. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis, Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza.

Initial therapy of chronic lymphocytic leukemia

Only chronic lymphocytic leukemia (CLL) patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. Prognostic risk factor profile and comorbidity burden are most relevant for the choice of treatment. For physically fit patients, chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab remains the current standard therapy. For unfit patients, treatment with an anti-CD20 antibody (obinutuzumab or rituximab or ofatumumab) plus milder chemotherapy (chlorambucil) may be applied. Patients with a del(17p) or TP53 mutation should be treated with the kinase inhibitors ibrutinib or a combination of idelalisib and rituximab. Clinical trials over the next several years will determine, whether kinase inhibitors, other small molecules, immunotherapeutics, or combinations thereof will further improve outcomes for patients with CLL.

Safety and efficacy of different lenalidomide starting doses in patients with relapsed or refractory chronic lymphocytic leukemia: results of an international multicenter double-blinded randomized phase II trial

The objective of this study was to evaluate the safety and efficacy of different lenalidomide starting doses in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). CLL patients were randomized to receive lenalidomide at initial doses of 5, 10, or 15 mg/d (N = 103). Doses were escalated by 5 mg every 28-d up to a maximum of 25 mg/d; dose reductions in up to 5 mg decrements were permitted. The most common grade ≥3 adverse events (AEs) were neutropenia and thrombocytopenia. Ten patients died during therapy (four deaths considered as related to lenalidomide); 12 patients experienced second primary malignancies. The most common cause for treatment discontinuation was AEs. Overall response rates were similar across arms. Progression-free survival and overall survival rates were longer in patients who escalated treatment (to 15 or 20 mg/d) versus those who did not. Lower starting doses allowed subsequent dose escalation of lenalidomide while maintaining an acceptable tolerability profile in patients with relapsed/refractory CLL.

Targeted therapies for CLL: Practical issues with the changing treatment paradigm

Chemoimmunotherapy (CIT) such as FCR (fludarabine, cyclophosphamide, rituximab) has been the standard first-line therapy for younger patients with CLL. In the last few years, several novel targeted therapies have been developed for patients with CLL. These include B-cell receptor (BCR) inhibitors such as Bruton tyrosine kinase (BTK) inhibitors, PI3 kinase inhibitors, and Syk inhibitors, novel anti-CD20 monoclonal antibodies such as ofatumumab and obinutuzumab, and Bcl-2 antagonists such as venetoclax (ABT-199). Strategies targeting the immune system such as lenalidomide, chimeric antigen receptor (CAR) T cells, and more recently, checkpoint inhibitors, are in clinical development. Ibrutinib and idelalisib are already approved for patients with relapsed and refractory CLL. Ibrutinib is also approved for first-line treatment of CLL patients with del(17p). Several ongoing phase III clinical trials with novel therapies will further define the role of targeted agents in CLL.

Lenalidomide in chronic lymphocytic leukemia: the present and future in the era of tyrosine kinase inhibitors

Lenalidomide is an immunomodulatory agent (IMiD) clinically active in chronic lymphocytic leukemia (CLL), both in heavily pre-treated patients and upfront. Lenalidomide has a unique mechanism of action in CLL. Its efficacy relies on a multifactorial mode-of-action (MOA), comprising a plethora of immunomodulatory actions, the disruption of mutualistic interactions inside CLL microenvironment and direct effects against leukemic cells. In the last few years, a number of new and highly effective drugs appeared in the scenario of CLL therapeutic options, i.e. tyrosine kinase inhibitors (TKIs), showing a good safety profile and impressive clinical response, also in high-risk patients. In this review, we describe the data from clinical studies about lenalidomide efficacy in CLL and we critically dissect the different mechanisms of action of this drug. We point the attention on open issues, including drug dosage and administration schedule, prediction of clinical response to lenalidomide, and combination therapeutic strategies. This overview would be useful to envision a possible role of lenalidomide in the treatment flow-chart of CLL, exploiting its peculiar MOA and also exploring the possible synergetic effect with new drugs.

Novelties in the management of B-cell malignancies: B-cell receptor signaling inhibitors and lenalidomide

B-cell lymphoproliferative disorders comprise 85% of Non-Hodgkin's lymphomas. Despite successful chemoimmunotherapy regimens, responses are not durable and the outcome is fatal in a considerable portion of patients. There is an inevitable need for less toxic and more potent therapeutic agents. Over the recent years, a plethora of agents including monoclonal antibodies, Bcl-2 antagonists, tyrosine kinase inhibitors, cyclin-dependent kinase inhibitors, mTOR inhibitors and immunomodulatory drugs have been developed in B-cell malignancies. The aim of this paper is to focus on B-cell receptor signaling inhibitors and lenalidomide as an immunomodulatory drug and to provide insight on how and when to incorporate these agents into the treatment algorithms.

Treatment of chronic lymphocytic leukemia with monoclonal antibodies, where are we heading?

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in the western world and monoclonal antibodies (mAbs) are important part of CLL treatment. The goal of this article was to summarize current literature on the position of mAbs in CLL treatment and to mention factors influencing effectiveness of mAbs in CLL. Several new mAbs have been developed and investigated in CLL over the past few years. Mainly anti-CD20 monoclonal antibodies are still used routinely in CLL therapy. Unfortunately, the clinical application of mAbs needs to be further improved. Novel combinations and sequences of mAbs with other compounds need to be studied in clinical trials in order to increase overall response rate and prolong remission duration. Mechanisms of action of mAbs or mechanisms of resistance to mAbs have to be also investigated to predict effectiveness of mAb in particular patient.

Targeting chronic lymphocytic leukemia cells in the tumor microenviroment: A review of the in vitro and clinical trials to date

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Despite significant advances in therapy over the last decade CLL remains incurable. Current front-line therapy often consists of chemoimmunotherapy-based regimens, most commonly the fludarabine, cyclophosphamide plus rituximab combination, but rates of relapse and refractory disease are high among these patients. Several key signaling pathways are now known to mediate the survival and proliferation of CLL cells in vivo, the most notable of which are the pathways mediated by the B-cell receptor (BCR) and cytokine receptors. A better understanding of the pathogenesis of the disease, the underlying biology of the CLL-cell and the roles of the tumour microenvironment has provided the rationale for trials of a range of novel, more targeted therapeutic agents. In particular, clinical trials of ibrutinib and idelalisib, which target the Brutons tyrosine kinase and the delta isoform of phosphoinositol-3 kinase components of the BCR signaling pathway respectively, have shown extremely promising results. Here we review the current literature on the key signaling pathways and interactions of CLL cells that mediate the survival and proliferation of the leukemic cells. For each we describe the results of the recent clinical trials and in vitro studies of novel therapeutic agents.

Emerging immunological drugs for chronic lymphocytic leukemia

INTRODUCTION

Over the last few years, several new immunological drugs, particularly monoclonal antibodies (mAbs), immunomodulatory drugs and B-cell receptor (BCR) pathway inhibitors have been developed and investigated in chronic lymphocytic leukemia (CLL). This article summarizes recent discoveries regarding their mechanism of action, pharmacological properties, clinical activity and toxicity, as well as the emerging role of these agents in CLL.

AREAS COVERED

A literature review of mAbs, BCR pathway inhibitors and immunomodulating drugs was conducted of the MEDLINE database via PubMed for articles in English. Publications from 2000 through February 2015 were scrutinized. The search terms used were alemtuzumab, BI 836826, duvelisib ibrutinib, idelalisib, lenalidomide, monoclonal antibodies, MEDI-551, MOR208, obinutuzumab, ocaratuzumab, ofatumumab, ONO-4059, otlertuzumab, spebrutinib, veltuzumab and XmAb5574 in conjunction with CLL. Conference proceedings from the previous 5 years of the American Society of Hematology, European Hematology Association, American Society of Clinical Oncology, and ACR/ARHP Annual Scientific Meetings were searched manually. Additional relevant publications were obtained by reviewing the references from the chosen articles.

EXPERT OPINION

The use of mAbs, BCR inhibitors and immunomodulating drugs is a promising new strategy for chemotherapy-free treatment of CLL. However, definitive data from ongoing and future clinical trials will aid in better defining the status of immunological drugs in the treatment of this disease.

Reduced-dose fludarabine, cyclophosphamide, and rituximab (FCR-Lite) plus lenalidomide, followed by lenalidomide consolidation/maintenance, in previously untreated chronic lymphocytic leukemia

Fludarabine, cyclophosphamide, and rituximab (FCR) remains the standard of care for fit chronic lymphocytic leukemia (CLL) patients requiring first therapy. However, side effects can be significant, and patients with poor risk features have inferior outcomes. The purpose of this study was to evaluate reduced-dose FCR (FCR-Lite) plus lenalidomide (FCR(2) ) followed by lenalidomide maintenance as a strategy to shorten immunochemotherapy in untreated CLL. Patients received four to six cycles of FCR(2) . Patients who were minimal residual disease (MRD) negative in peripheral blood (PB) and bone marrow (BM) initiated 12 months of lenalidomide maintenance after either four or six cycles (based on MRD status). The primary study endpoint was the complete response (CR) rate after four cycles of FCR(2) . Twenty patients were evaluable. After four cycles of FCR(2) , response rates were: CR, 45.0%; CR with incomplete blood count recovery (CRi), 5.0%; partial response (PR), 45.0%; and stable disease (SD), 5.0%. BM and PB samples from 27.8% and 52.9% of patients, respectively, were MRD negative. After six cycles, response rates were: CR, 58.3%; CRi, 16.7%; and PR, 25.0%. BM and PB samples from 50.0% and 72.7% of patients, respectively, were MRD negative. Overall, 75% of evaluable patients achieved a CR or CRi following FCR(2) . After 17.4 months of median follow-up, one progression and one death occurred. Our findings suggest that FCR(2) combines encouraging clinical activity with acceptable toxicity in previously untreated CLL. Lenalidomide can be safely added to FCR and may reduce chemotherapy exposure without compromising outcomes.

Expanding role of lenalidomide in hematologic malignancies

Lenalidomide is an immunomodulatory agent that has been approved by the US Food and Drug Administration for treatment of multiple myeloma, deletion 5q myelodysplastic syndrome, and mantle cell lymphoma. In addition, it has clinical activity in lymphoproliferative disorders and acute myeloid leukemia. The mode of action includes immunomodulatory, anti-inflammatory, antiangiogenic, and antiproliferative mechanisms. The antitumor effect is a result of direct interference of key pathways in tumor cells and indirect modulation of the tumor microenvironment. There has been no recent collective review on lenalidomide in multiple myeloma, myelodysplastic syndrome/acute myeloid leukemia, and lymphoma. This review summarizes the results of current clinical studies of lenalidomide, alone and in combination with other agents, as a therapeutic option for various hematologic malignancies.

Haematological malignancies: at the forefront of immunotherapeutic innovation

The recent successes of cancer immunotherapies have stimulated interest in the potential widespread application of these approaches; haematological malignancies have provided both initial proofs of concept and an informative testing ground for various immune-based therapeutics. The immune-cell origin of many of the blood malignancies provides a unique opportunity both to understand the mechanisms of cancer immune responsiveness and immune evasion, and to exploit these mechanisms for therapeutic purposes.