Single-agent lenalidomide in the treatment of previously untreated chronic lymphocytic leukemia

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.

Maintenance therapy for chronic lymphocytic leukaemia

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is the most common lymphoproliferative disease in adults and currently remains incurable. As the progression-free period shortens after each successive treatment, strategies such as maintenance therapy are needed to improve the degree and duration of response to previous therapies. Monoclonal antibodies, immunomodulatory agents, and targeted therapies are among the available options for maintenance therapy. People with CLL who achieve remission after previous therapy may choose to undergo medical observation or maintenance therapy to deepen the response. Even though there is widespread use of therapeutic maintenance agents, the benefits and harms of these treatments are still uncertain.

OBJECTIVES

To assess the effects and safety of maintenance therapy, including anti-CD20 monoclonal antibody, immunomodulatory drug therapy, anti-CD52 monoclonal antibody, Bruton tyrosine kinase inhibitor, and B-cell lymphoma-2 tyrosine kinase inhibitor, for individuals with CLL.

SEARCH METHODS

We conducted a comprehensive literature search for randomised controlled trials (RCTs) with no language or publication status restrictions. We searched CENTRAL, MEDLINE, Embase, and three trials registers in January 2022 together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included RCTs with prospective identification of participants. We excluded cluster-randomised trials, cross-over trial designs, and non-randomised studies. We included studies comparing maintenance therapies with placebo/observation or head-to-head comparisons.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. We assessed risk of bias in the included studies using Cochrane's RoB 1 tool for RCTs. We rated the certainty of evidence for the following outcomes using the GRADE approach: overall survival (OS), health-related quality of life (HRQoL), grade 3 and 4 adverse events (AEs), progression-free survival (PFS), treatment-related mortality (TRM), treatment discontinuation (TD), and all adverse events (AEs).

MAIN RESULTS

We identified 11 RCTs (2393 participants) that met the inclusion criteria, including seven trials comparing anti-CD20 monoclonal antibodies (mAbs) (rituximab or ofatumumab) with observation in 1679 participants; three trials comparing immunomodulatory drug (lenalidomide) with placebo/observation in 693 participants; and one trial comparing anti-CD 52 mAbs (alemtuzumab) with observation in 21 participants. No comparisons of novel small molecular inhibitors were found. The median age of participants was 54.1 to 71.7 years; 59.5% were males. The type of previous induction treatment, severity of disease, and baseline stage varied among the studies. Five trials included early-stage symptomatic patients, and three trials included advanced-stage patients (Rai stage III/IV or Binet stage B/C). Six trials reported a frequent occurrence of cytogenic aberrations at baseline (69.7% to 80.1%). The median follow-up duration was 12.4 to 73 months. The risk of selection bias in the included studies was unclear. We assessed overall risk of performance bias and detection bias as low risk for objective outcomes and high risk for subjective outcomes. Overall risk of attrition bias, reporting bias, and other bias was low. Anti-CD20 monoclonal antibodies (mAbs): rituximab or ofatumumab maintenance versus observation Anti-CD20 mAbs maintenance likely results in little to no difference in OS (hazard ratio (HR) 0.94, 95% confidence interval (CI) 0.73 to 1.20; 1152 participants; 3 studies; moderate-certainty evidence) and likely increases PFS significantly (HR 0.61, 95% CI 0.50 to 0.73; 1255 participants; 5 studies; moderate-certainty evidence) compared to observation alone. Anti-CD20 mAbs may result in: an increase in grade 3/4 AEs (rate ratio 1.34, 95% CI 1.06 to 1.71; 1284 participants; 5 studies; low-certainty evidence); little to no difference in TRM (risk ratio 0.82, 95% CI 0.39 to 1.71; 1189 participants; 4 studies; low-certainty evidence); a slight reduction to no difference in TD (risk ratio 0.93, 95% CI 0.72 to 1.20; 1321 participants; 6 studies; low-certainty evidence); and an increase in all AEs (rate ratio 1.23, 95% CI 1.03 to 1.47; 1321 participants; 6 studies; low-certainty evidence) compared to the observation group. One RCT reported that there may be no difference in HRQoL between the anti-CD20 mAbs (ofatumumab) maintenance and the observation group (mean difference -1.70, 95% CI -8.59 to 5.19; 480 participants; 1 study; low-certainty evidence). Immunomodulatory drug (IMiD): lenalidomide maintenance versus placebo/observation IMiD maintenance therapy likely results in little to no difference in OS (HR 0.91, 95% CI 0.61 to 1.35; 461 participants; 3 studies; moderate-certainty evidence) and likely results in a large increase in PFS (HR 0.37, 95% CI 0.19 to 0.73; 461 participants; 3 studies; moderate-certainty evidence) compared to placebo/observation. Regarding harms, IMiD maintenance therapy may result in an increase in grade 3/4 AEs (rate ratio 1.82, 95% CI 1.38 to 2.38; 400 participants; 2 studies; low-certainty evidence) and may result in a slight increase in TRM (risk ratio 1.22, 95% CI 0.35 to 4.29; 458 participants; 3 studies; low-certainty evidence) compared to placebo/observation. The evidence for the effect on TD compared to placebo is very uncertain (risk ratio 0.71, 95% CI 0.47 to 1.05; 400 participants; 2 studies; very low-certainty evidence). IMiD maintenance therapy probably increases all AEs slightly (rate ratio 1.41, 95% CI 1.28 to 1.54; 458 participants; 3 studies; moderate-certainty evidence) compared to placebo/observation. No studies assessed HRQoL. Anti-CD52 monoclonal antibodies (mAbs): alemtuzumab maintenance versus observation Maintenance with alemtuzumab may have little to no effect on PFS, but the evidence is very uncertain (HR 0.55, 95% CI 0.32 to 0.95; 21 participants; 1 study; very low-certainty evidence). We did not identify any study reporting the outcomes OS, HRQoL, grade 3/4 AEs, TRM, TD, or all AEs.

AUTHORS' CONCLUSIONS

There is currently moderate- to very low-certainty evidence available regarding the benefits and harms of maintenance therapy in people with CLL. Anti-CD20 mAbs maintenance improved PFS, but also increased grade 3/4 AEs and all AEs. IMiD maintenance had a large effect on PFS, but also increased grade 3/4 AEs. However, none of the above-mentioned maintenance interventions show differences in OS between the maintenance and control groups. The effects of alemtuzumab maintenance are uncertain, coupled with a warning for drug-related infectious toxicity. We found no studies evaluating other novel maintenance interventions, such as B-cell receptor inhibitors, B-cell leukaemia-2/lymphoma-2 inhibitors, or obinutuzumab.

Reshaping the tumor microenvironment: The versatility of immunomodulatory drugs in B-cell neoplasms

Immunomodulatory drugs (IMiDs) such as thalidomide, lenalidomide and pomalidomide are antitumor compounds that have direct tumoricidal activity and indirect effects mediated by multiple types of immune cells in the tumor microenvironment (TME). IMiDs have shown remarkable therapeutic efficacy in a set of B-cell neoplasms including multiple myeloma, B-cell lymphomas and chronic lymphocytic leukemia. More recently, the advent of immunotherapy has revolutionized the treatment of these B-cell neoplasms. However, the success of immunotherapy is restrained by immunosuppressive signals and dysfunctional immune cells in the TME. Due to the pleiotropic immunobiological properties, IMiDs have shown to generate synergetic effects in preclinical models when combined with monoclonal antibodies, immune checkpoint inhibitors or CAR-T cell therapy, some of which were successfully translated to the clinic and lead to improved responses for both first-line and relapsed/refractory settings. Mechanistically, despite cereblon (CRBN), an E3 ubiquitin ligase, is considered as considered as the major molecular target responsible for the antineoplastic activities of IMiDs, the exact mechanisms of action for IMiDs-based TME re-education remain largely unknown. This review presents an overview of IMiDs in regulation of immune cell function and their utilization in potentiating efficacy of immunotherapies across multiple types of B-cell neoplasms.

Lenalidomide enhances CD23.CAR T cell therapy in chronic lymphocytic leukemia

Chimeric antigen receptors (CAR)-modified T cells are an emerging therapeutic tool for chronic lymphocytic leukemia (CLL). However, in patients with CLL, well-known T-cell defects and the inhibitory properties of the tumor microenvironment (TME) hinder the efficacy of CAR T cells. We explored a novel approach combining CARs with lenalidomide, an immunomodulatory drug that tempers the immunosuppressive activity of the CLL TME. T cells from patients with CLL were engineered to express a CAR specific for CD23, a promising target antigen. Lenalidomide maintained the in vitro effector functions of CD23.CAR⁺ T cells effector functions in terms of antigen-specific cytotoxicity, cytokine release and proliferation. Overall, lenalidomide preserved functional CAR T-CLL cell immune synapses. In a Rag2^-/-γ_c^-/--based xenograft model of CLL, we demonstrated that, when combined with low-dose lenalidomide, CD23.CAR⁺ T cells efficiently migrated to leukemic sites and delayed disease progression when compared to CD23.CAR⁺ T cells given with rhIL-2. These observations underline the therapeutic potential of this novel CAR-based combination strategy in CLL.

Effect of Lenalidomide Maintenance in Chronic Lymphocytic Leukemia: A Meta-Analysis and Trial-Sequential Analysis

Chronic lymphocytic leukemia (CLL) is the most common lymphoproliferative disease in adults. Despite durable responses and sustained remission rates to frontline therapy, CLL is still incurable within standard therapy and eventually relapses. Maintenance therapies aim to achieve deep remission. However, the efficacy and safety of lenalidomide maintenance are still debated. Randomized controlled trials published before March 2022 were retrieved from databases. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Trial sequential analysis examined analytical power in primary outcomes. Secondary outcomes were Grade 3–4 neutropenia, treatment discontinuation (TD), serious adverse events (SAE), and fatal adverse events (FAE). Hazard (HR) and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Four articles (733 patients) met the selection criteria. Lenalidomide maintenance was associated with a statistically significant effect in prolonging PFS (HR, 0.43; 95% CI, 0.28–0.68; I² = 57%) and higher proportion of SAE (OR 4.64; 95% CI 2.96–7.26; I² = 0%) and exhibited no difference in OS (HR, 0.62; 95% CI, 0.29–1.30; I² = 52%) observation/placebo. It showed no significant difference compared with observation/placebo regarding Grade 3–4 neutropenia (OR 2.30; 95% CI 0.84–6.28; I² = 81%), TD (OR 0.76; 95% CI 0.29–1.99; I² = 84%), and FAE (OR 0.86; 95% CI 0.28–2.63; I² = 0%). Lenalidomide maintenance can prolong PFS in CLL. Further studies should verify its effect on OS.

Tumor Flare Reaction in a Classic Hodgkin Lymphoma Patient Treated With Brentuximab Vedotin and Tislelizumab: A Case Report

Background

Tumor flare reaction (TFR) is a clinical syndrome, which is mainly associated with painful and swollen lymph nodes or splenomegaly, slight fever, bone pain, and skin rash during treatment with immune-related drugs, causing difficulty in distinguishing TFR from disease progression. Brentuximab vedotin (BV) and programmed death 1 (PD-1) inhibitor are two ideal drugs used for the treatment of classic Hodgkin lymphoma, but few studies have reported their adverse effects in association with TFR. The efficacy and safety of monotherapy or combination therapy with these drugs needs to be further evaluated. It is essential to determine whether treated patients can develop TFR, thus enabling more accurate diagnosis and treatment.

Case presentation

A 26-year-old female patient, diagnosed with classic Hodgkin lymphoma, had received 2 + 3 cycles of ABVD chemotherapy (a combination of adriamycin, bleomycin, vinblastine, and dacarbazine) and 4 cycles of PD-1 inhibitor (tislelizumab) therapy but exhibited poor efficacy. Subsequently, she was given combination therapy of BV (100 mg) + tislelizumab (200 mg). However, a slight fever, painful and swollen axillary lymph nodes, multiple skin rashes with pruritus, joint pain, and fatigue with poor appetite appeared during the treatment. Ultrasound (US) scans revealed that multiple lymph nodes were significantly enlarged. After treatment with low-dose dexamethasone and cetirizine, the symptoms were alleviated. A biopsy of the left axillary lymph node revealed that lymphoid tissue exhibited proliferative changes, without tumor cell infiltration. These findings were consistent with the clinical and pathological manifestations of TFR.

Conclusion

Combination therapy with BV and PD-1 inhibitor was effective in the treatment of relapsed or refractory classic Hodgkin lymphoma. The results suggest that the combination therapy may cause TFR, and biopsy and also continuous imaging observation are important to determine the disease stage. This approach allows clinicians to decide whether to continue the current treatment plan, and alerts them to the occurrence of excessive activation of the immune system.

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.

T Cell Defects and Immunotherapy in Chronic Lymphocytic Leukemia

In the past few years, independent studies have highlighted the relevance of the tumor microenvironment (TME) in cancer, revealing a great variety of TME-related predictive markers, as well as identifying novel therapeutic targets in the TME. Cancer immunotherapy targets different components of the immune system and the TME at large in order to reinforce effector mechanisms or relieve inhibitory and suppressive signaling. Currently, it constitutes a clinically validated treatment for many cancers, including chronic lymphocytic leukemia (CLL), an incurable malignancy of mature B lymphocytes with great dependency on microenvironmental signals. Although immunotherapy represents a promising therapeutic option with encouraging results in CLL, the dysfunctional T cell compartment remains a major obstacle in such approaches. In the scope of this review, we outline the current immunotherapeutic treatment options in CLL in the light of recent immunogenetic and functional evidence of T cell impairment. We also highlight possible approaches for overcoming T cell defects and invigorating potent anti-tumor immune responses that would enhance the efficacy of immunotherapy.

Impact of COVID-19 in patients with lymphoid malignancies

The first cases of coronavirus disease 2019 (COVID-19) were detected in Wuhan, China, in December 2019. Since this time a concerted global effort of research and observational data gathering has meant that a great deal has been learnt about the impact of COVID-19 in patients with lymphoid malignancies. Approximately one-third of patients with lymphoid malignancies who acquire COVID-19 and have it severely enough to require hospital assessment will die from this infection. Major risk factors for a poor outcome are age and co-morbidities, but when these are taken into account lymphoma patients have a slightly greater than 2-fold increased risk compared to the general population. Notably, despite early concerns regarding the particular vulnerability of lymphoma patients due to the immunosuppressive effects of therapy, active treatment, including B-cell depleting agents such as rituximab, do not appear to be associated with an increased risk of a poorer outcome. Indeed, some treatments such as ibrutinib may be beneficial due to their modulation of the potential fatal hyperinflammatory phase of infection. There are risks associated with hemopoietic stem cell transplantation, but the collective experience is that these can be minimized by preventive strategies and that the majority of transplant recipients with COVID-19 infection will survive. Many questions remain including those regarding the outcome of COVID-19 infection in the rarer lymphoid malignancies and the efficacy of COVID-19 vaccines in lymphoma patients. This review aims to discuss these issues and present a summary of the current knowledge of the impact of COVID-19 in lymphoid malignancies.

A comparison of the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone in the treatment of multiple myeloma

OBJECTIVE

To explore the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone (DXMS) in the treatment of multiple myeloma (MM).

METHODS

A total of 80 patients with newly diagnosed MM were randomly divided into the ID group (ixazomib + DXMS, n=40) and the RD group (lenalidomide + DXMS, n=40). All patients were given DXMS orally on the 1st, 8th, 15th, and 22nd day of the treatment cycle (20 mg each time). The patients in the ID group also received 4 mg of ixazomib citrate capsules orally on the 1st, 8th, and 15th day of the treatment cycle, whereas those in the RD group received 25 mg of lenalidomide capsules orally from the 1st to the 21st day of the treatment cycle continuously. The primary outcome measure was progression-free survival (PFS) within 5 years, and the secondary outcome measures were overall survival (OS), overall response rate (ORR), quality of life, and safety.

RESULTS

The median PFS and median OS in the ID group were similar to those in the RD group (30.03 and 50.21 months vs. 25.04 and 46.33 months, both P>0.05). The ID group had higher complete remission rate (13 cases vs. 5 cases, P<0.05), but similar ORR compared with the RD group (90.00% vs. 82.50%, P>0.05). After treatment, the pain intensity assessed by Numeric Rating Scale and the functional impairment measured by Karnofsky Performance Status Scale of the two groups were both relieved (both P<0.001), and no intergroup differences in these two markers were observed (both P>0.05). The incidence of grade 1-2 peripheral neuropathy in the ID group was higher than that in the RD group (30.00% vs. 20.00%, P=0.032). There were no differences in other adverse reactions between the two groups (all P>0.05).

CONCLUSION

Compared with the combination of lenalidomide and DXMS, ixazomib combined with DXMS can achieve higher complete remission rate and more improved PFS and OS in patients with newly diagnosed MM, which is a safe and effective method.

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).

Tumour flare reaction in cancer treatments: a comprehensive literature review

In the past decade, tumour flare reaction (TFR) was considered as a new side effect associated with immunomodulatory agents (IMiDs) and as a condition of chronic lymphocytic leukaemia (CLL). However, this phenomenon is also observed with immune checkpoint inhibitors in solid tumours. It is still poorly understood and its incidence is underestimated. TFR has been associated with morbidity, therefore, early recognition and management of patients with TFR is critical. An exhaustive literature research between 1985 and 2016 was performed using PubMed; American Society of Clinical Oncology and American Society of Hematology abstracts reporting TFR or pseudoprogression were identified. The incidence of TFR in CLL ranged from 28 to 58%. Tumour response in patients treated beyond progression was reported in 9.7% with ipilimumab, 10% with nivolumab, 6.7 and 12% with pembrolizumab, and in renal cell carcinoma 69% with nivolumab. Rare life-threatening or fatal cases were reported; symptoms were usually mild. Studies showed that treating patients beyond progression yielded tumour responses, considering TFR as predictive of response. Treatment with immunomodulatory agents is associated with TFR, often misinterpreted as progression. Therefore, the identification of appropriate clinical benefit criteria and the use of immune-related response criteria in prospective trials for a better understanding are compulsory.

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).

Tumour lysis syndrome in patients with chronic lymphocytic leukaemia treated with BCL-2 inhibitors: risk factors, prophylaxis, and treatment recommendations

Tumour lysis syndrome is a complication of chemotherapy for haematological malignancies; in particular, aggressive leukaemias and lymphomas. For haematological malignancies, targeted therapies, such as small molecule inhibitors and monoclonal antibodies, have a high anti-tumour activity, are well tolerated, and have a low incidence of associated tumour lysis syndrome. The BCL-2 inhibitor venetoclax has a high anti-tumour activity in chronic lymphocytic leukaemia, achieving deep remissions by potently inducing apoptosis and increasing the risk for tumour lysis syndrome. In this Viewpoint, we discuss the pathophysiology, risk factors, monitoring, changes in laboratory parameters, and clinical manifestations of tumour lysis syndrome, and the prophylaxis and treatments available for this complication. Prophylaxis and treatment strategies have been implemented as standard of care in patients receiving venetoclax to minimise the risk of both laboratory and clinical manifestations of tumour lysis syndrome.

Lenalidomide plus rituximab (R2 ) in previously untreated marginal zone lymphoma: subgroup analysis and long-term follow-up of an open-label phase 2 trial

Lack of consensus for first‐line marginal zone lymphoma (MZL) treatment and toxicities associated with currently available systemic therapies have inspired evaluation of immunotherapeutic agents yielding robust outcomes with improved tolerability. We previously reported durable efficacy with first‐line lenalidomide and rituximab (R²) in follicular lymphoma, MZL and small lymphocytic lymphoma with a subsequent long‐term follow‐up shown here in MZL patients. This phase 2 investigator‐initiated study included previously untreated, stage III/IV MZL patients treated with lenalidomide 20 mg/day on days 1–21 and rituximab 375 mg/m² on day 1 of each 28‐day cycle, continuing in responders for ≥6–12 cycles. The primary endpoint was overall response rate (ORR); secondary endpoints were complete and partial response (CR, PR), safety, and progression‐free survival (PFS). The ORR was 93% with 70% attaining CR/CR unconfirmed. At median follow‐up of 75·1 months, median PFS was 59·8 months and 5‐year OS was 96%. Most non‐haematological adverse events (AE) were grade 1/2. Grade 3 haematological AEs were neutropenia (33%) and leucopenia (7%), and grade 4 were leucopenia (3%) and thrombocytopenia (3%). Two patients died of secondary malignancies; no treatment‐related fatalities occurred. With extended follow‐up, outcomes for MZL patients receiving R² were robust with no unexpected late or delayed toxicities.

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.

Immunomodulatory Drugs Exert Anti-Leukemia Effects in Acute Myeloid Leukemia by Direct and Immunostimulatory Activities

Immunomodulatory drugs (IMiDs) are anticancer drugs with immunomodulatory, anti-angiogenesis, anti-proliferative, and pro-apoptotic properties. IMiDs are currently used for the treatment of multiple myeloma, myelodysplastic syndrome, and B-cell lymphoma; however, little is known about efficacy in acute myeloid leukemia (AML). We proposed in this study to investigate the relevance of IMiDs therapy for AML treatment. We evaluated the effect of IMiDs on primary AML blasts (n = 24), and the impact in natural killer (NK) cell-mediated immunosurveillance of AML. Using primary AML cells and an immunodeficient mouse leukemia xenograft model, we showed that IMiDs induce AML cell death in vitro and impair leukemia progression in vivo. In addition, treatment of AML blasts with IMiDs resulted in enhanced allogeneic NK cell anti-leukemia reactivity. Treatment by pomalidomide of AML blasts enhanced lysis, degranulation, and cytokine production by primary allogeneic NK cells. Furthermore, the treatment with lenalidomide of patients with myeloid malignancies resulted in NK cell phenotypic changes similar to those observed in vitro. IMiDs increased CD56 and decreased NKp30, NKp46, and KIR2D expression on NK cells. Finally, AML blasts treatment with IMiDs induced phenotypic alterations including downregulation of HLA-class I. The effect of pomalidomide was not correlated with cereblon expression and A/G polymorphism in AML cells. Our data revealed, a yet unobserved, dual effects on AML affecting both AML survival and their sensitivity to NK immunotherapy using IMiDs. Our study encourages continuing investigation for the use of IMiDs in AML, especially in combination with conventional therapy or immunotherapy strategies.

Chronic Lymphocytic Leukemia: Diagnosis and Treatment

The complexity of the treatment of patients with chronic lymphocytic leukemia has increased substantially over the past several years as a consequence of the advent of novel biological agents such as ibrutinib, idelalisib, and venetoclax, as well as increasingly potent anti-CD20 monoclonal antibodies. In addition, the identification of molecular predictive markers and the introduction of more sensitive and sophisticated techniques to assess minimal residual disease have allowed optimization of the use of chemoimmunotherapy and targeted therapies and may become standard of care in the future. This review summarizes the diagnosis, prognostication, and treatment of patients with chronic lymphocytic leukemia with emphasis on new prognostic and predictive factors and novel treatment strategies.

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.

Critical molecular pathways in CLL therapy

Chronic lymphocytic leukemia (CLL), the most frequent type of leukemia in western countries, is characterized by the progressive accumulation in blood, bone marrow and lymphoid tissues of monoclonal B lymphocytes with a characteristic immunophenotype. Despite advances in therapy and improved outcome, in most instances CLL is an incurable disorder. Signaling via the B-cell receptor (BCR), the upregulation of anti-apoptotic proteins, and the cross-talk between CLL cells and microenvironment constitute key factors in the pathogenesis of CLL. Currently, inhibitors of kinases like BTK or PI3K blocking BCR signaling, and molecules that mimic the BH3 domain to compete with BCL-2 are established tools in the treatment of CLL. As the complex biology of CLL is rapidly unfolding, the number of small molecules targeting CLL molecular pathways is increasing and it is likely that they will further improve the outcome of patients with this form of leukemia.

Clinical implications of cancer gene mutations in patients with chronic lymphocytic leukemia treated with lenalidomide

Lenalidomide is clinically active in chronic lymphocytic leukemia (CLL), but its effectiveness in the context of the CLL mutational landscape is unknown. We performed targeted capture sequencing of 295 cancer genes in specimens from 102 CLL patients with treatment-naïve disease (TN patients) and 186 CLL patients with relapsed/refractory disease (R/R patients) who received lenalidomide-based therapy at our institution. The most frequently mutated gene was SF3B1 (15%), followed by NOTCH1 (14%) and TP53 (14%), with R/R patients having significantly more TP53 mutations than did TN patients. Among all lenalidomide-treated patients, del(17p) (P ≤ .001), del(11q) (P = .032), and complex karyotype (P = .022), along with mutations in TP53 (P ≤ .001), KRAS (P = .034), and DDX3X (P ≤ .001), were associated with worse overall response (OR). R/R patients with SF3B1 and MGA mutations had significantly worse OR (P = .025 and .035, respectively). TN and R/R patients with del(17p) and TP53 mutations had worse overall survival (OS) and progression-free survival (PFS). In R/R patients, complex karyotype and SF3B1 mutations were associated with worse OS and PFS; DDX3X mutations were associated with worse PFS only. Weibull regression multivariate analysis revealed that TP53 aberrations (del(17p), TP53 mutation, or both), along with complex karyotype and SF3B1 mutations, were associated with worse OS in the R/R cohort. Taken together, cancer gene mutations in CLL contribute to the already comprehensive risk stratification and add to prognosis and response to treatment. The related trials were registered at www.clinicaltrials.gov as #NCT00267059, #NCT00535873, #NCT00759603, #NCT01446133, and #NCT01002755.

Elevated absolute NK cell counts in peripheral blood predict good prognosis in chronic lymphocytic leukemia

PURPOSE

The aim of this study was to investigate the prognostic significance of the absolute natural killer (NK) cell counts in peripheral blood in patients with chronic lymphocytic leukemia (CLL).

METHODS

A total of 273 previously untreated patients with CLL from April 2004 and October 2015 were enrolled into this retrospective study. We analysed the T cell subsets of all patients and figured out the number of NK cells. Comparisons of NK cell count as continuous parameter in different groups were described using Mann-Whitney U test and the Kruskal-Wallis test. Kaplan-Meier method was used to survival analysis, and the Cox proportional hazards models were used for the estimation of prognostic factors.

RESULTS

NK cell counts were calculated in 273 therapy-naive CLL patients, and higher number of NK cell was observed in those with Binet stage A/B, ZAP-70 < 20%, normal serum albumin and β₂-microglobulin levels. Using a NK cell count cut-off of 0.40 × 10⁹/L, patients with lower NK cell count (< 0.40 × 10⁹/L) had a significantly shorter overall survival (OS) than those with higher NK cell count (≥ 0.40 × 10⁹/L) (P = 0.0014). Multivariate analysis showed that NK cell counts remained its prognostic value. However, the effect of NK cell count on time to treatment was not significant.

CONCLUSIONS

Our results suggest that NK cell count is an independent prognostic marker for OS in patients with CLL and NK cell counts ≥ 0.40 × 10⁹/L can routinely be used to identify patients with favorable survival.

Managing Tumor Lysis Syndrome in the Era of Novel Cancer Therapies

Abstract Tumor lysis syndrome (TLS) is a potentially life-threatening emergency that can develop rapidly after the release of intracellular contents from lysed malignant cells. The advent of novel and targeted therapies that have improved tumor-killing efficacy has the potential to increase the risk of TLS when used as part of front-line therapy. A recent review of TLS risk in patients with hematologic malignancies treated with newer targeted agents highlighted the need to revisit TLS risk stratification and to describe the practical challenges of TLS prevention, treatment, and monitoring. Although this era of rapid development of novel cancer therapies provides new hope for patients with hematologic malignancies, it is essential to be prepared for TLS because monitoring and prophylaxis can almost always prevent severe and life-threatening consequences. Heightened awareness of the development of TLS with novel and targeted agents, accompanied by aggressive hydration and rational, risk-appropriate management, are the keys to successful outcomes.

Tumor Lysis Syndrome in Chronic Lymphocytic Leukemia with Novel Targeted Agents

Tumor lysis syndrome (TLS) is an uncommon but potentially life-threatening complication associated with the treatment of some cancers. If left untreated, TLS may result in acute renal failure, cardiac dysrhythmia, neurologic complications, seizures, or death. Tumor lysis syndrome is most commonly observed in patients with hematologic malignancies with a high proliferation rate undergoing treatment with very effective therapies. In chronic lymphocytic leukemia (CLL), historically, TLS has been observed less often, owing to a low proliferation rate and slow response to chemotherapy. New targeted therapies have recently been approved in the treatment of CLL, including the oral kinase inhibitors, idelalisib and ibrutinib, and the B-cell lymphoma-2 protein inhibitor, venetoclax. Several others are also under development, and combination strategies of these agents are being explored. This review examines the diagnosis, prevention, and management of TLS and summarizes the TLS experience in CLL clinical trials with newer targeted agents. Overall, the risk of TLS is small, but the consequences may be fatal; therefore, patients should be monitored carefully. Therapies capable of eliciting rapid response and combination regimens are increasingly being evaluated for treatment of CLL, which may pose a higher risk of TLS. For optimal management, patients at risk for TLS require prophylaxis and close monitoring with appropriate tests and appropriate management to correct laboratory abnormalities, which allows for safe and effective disease control.

IMPLICATIONS FOR PRACTICE

Tumor lysis syndrome (TLS) is a potentially fatal condition observed with hematologic malignancies, caused by release of cellular components in the bloodstream from rapidly dying tumor cells. The frequency and severity of TLS is partly dependent upon the biology of the disease and type of therapy administered. Novel targeted agents highly effective at inducing rapid cell death in chronic lymphocytic leukemia (CLL) may pose a risk for TLS in patients with tumors characterized by rapid growth, high tumor burden, and/or high sensitivity to treatment. In this review, prevention strategies and management of patients with CLL who develop TLS are described.

Lenalidomide maintenance therapy in previously treated chronic lymphocytic leukaemia (CONTINUUM): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

The efficacy and safety of lenalidomide as maintenance therapy after chemotherapy-based second-line therapy in patients with chronic lymphocytic leukaemia is unknown. Although kinase inhibitors can improve outcomes for some patients with relapsed and refractory disease, not all patients have access to these novel drugs. In this study, we aimed to assess the efficacy and safety of lenalidomide as maintenance therapy in patients with previously treated chronic lymphocytic leukaemia.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial (CONTINUUM) was done at 111 hospitals, medical centres, and clinics in 21 countries. Patients were eligible if they had chronic lymphocytic leukaemia; were aged 18 years or older; had been treated with two lines of therapy (with at least a partial response after second-line therapy); had received a purine analogue, bendamustine, anti-CD20 antibody, chlorambucil, or alemtuzumab as first-line or second-line treatment; and had an Eastern Cooperative Oncology Group performance score of 0-2. Eligible patients were randomly assigned (1:1) by an interactive voice-response system to receive either oral lenalidomide (2·5 mg/day) or matching oral placebo capsules (2·5 mg/day) for 28-day cycles, until disease progression or unacceptable toxicity. Lenalidomide dose escalation (to 5 mg or 10 mg per day) was permitted if the drug was well tolerated. Patients, investigators, and those completing data analyses were masked to treatment allocation. Randomisation was stratified by age, response to second-line therapy, and prognostic factors. Co-primary endpoints were progression-free survival and overall survival; the primary endpoint was later changed to overall survival after the data cutoff for this analysis. Secondary endpoints were time from randomisation to second disease progression or death (PFS2),³² tumour response (improvement in response and duration of response), safety, and health-related quality of life (HRQoL). Efficacy analyses were done in the intention-to-treat population. Safety was analysed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT00774345, and is closed to accrual, but follow-up is ongoing.

FINDINGS

Between Feb 16, 2009 and Sept 29, 2015, 314 patients with chronic lymphocytic leukaemia were enrolled and randomly assigned to receive either lenalidomide (n=160) or placebo (n=154). With a median follow-up of 31·5 months (IQR 18·9-50·8), there was no significant difference in overall survival between the lenalidomide and the placebo groups (median 70·4 months, 95% CI 57·5-not estimable [NE] vs NE, 95% CI 62·8-NE; hazard ratio [HR] 0·96, 95% CI 0·63-1·48; p=0·86). Progression-free survival was significantly longer in the lenalidomide group (median 33·9 months, 95% CI 25·5-52·5) than in the placebo group (9·2 months, 7·4-13·6; HR 0·40, 95% CI 0·29-0·55; p<0·0001). PFS2 was significantly longer in the lenalidomide group than in the placebo group (median 57·5 months [47·7-NE] vs 32·7 months [26·4-49·0]; HR 0·46, 95% CI 0·29-0·70; p<0·01). Improved responses from baseline were observed in ten (6%) of 160 lenalidomide-treated patients versus four (3%) of 154 placebo-treated patients (p=0·12). Median time to improved response was 12·2 weeks (IQR 7·2-22·5) in the lenalidomide group versus 76·3 weeks (20·2-182·6) in the placebo group. Duration of improved response was not estimable in either group (95% CI 22·9-NE in the lenalidomide group vs NE-NE for placebo). There were no clinically meaningful differences in HRQoL between lenalidomide-treated patients and placebo-treated patients, as measured by FACT-Leu and EQ-5D, during maintenance treatment. In the safety population, the most common grade 3 or 4 adverse events included neutropenia (94 [60%] of 157 patients in the lenalidomide group vs 35 [23%] of 154 patients in the placebo group), thrombocytopenia (26 [17%] vs ten [6%]), and diarrhoea (13 [8%] vs one [<1%]). There were five fatal adverse events (three [2%] patients in the lenalidomide group and two [1%] patients in the placebo group).

INTERPRETATION

Lenalidomide might delay time to subsequent therapy and does not adversely affect response to subsequent therapy. Chemoimmunotherapy followed by lenalidomide maintenance could be an effective treatment option for patients with chronic lymphocytic leukaemia who do not have access to kinase inhibitors.

FUNDING

Celgene Corporation.

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.

Feasibility of Lenalidomide Therapy for Persistent Chronic Lymphocytic Leukemia after Allogeneic Transplantation

In patients with chronic lymphocytic leukemia (CLL), persistence of disease after allogeneic stem cell transplantation (alloSCT) can result in poor outcomes. In an effort to improve these outcomes, patients with persistent CLL who were 90 to 100 days beyond alloSCT with no evidence of graft-versus-host-disease (GVHD) were randomized to receive lenalidomide or standard care (withdrawal of immunosuppression followed by donor lymphocyte infusion). Lenalidomide was initiated at 5 mg every other day and increased to 10 mg daily, if tolerated, in each patient. Of 38 patients enrolled, 17 (45%) met the eligibility criteria for randomization. Of these 17 patients, 8 were randomized to undergo lenalidomide therapy. Five (62%) patients had to stop taking the drug because of toxicity. The main reason for drug discontinuation was acute GVHD in 43% of patients. This incidence was 11% in the patients who were randomized to not receive lenalidomide. With a median follow-up of 2.6 years, the median survival was 3.4 years for those receiving lenalidomide. This was not reached in patients randomized to not receive lenalidomide and in patients in complete remission who were not randomized. These results suggested that treatments other than lenalidomide are needed for persistent CLL after alloSCT.

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.

New Pharmacotherapies in Chronic Lymphocytic Leukemia

The authors present the clinical outcomes and therapeutic application of newly approved pharmacotherapies for chronic lymphocytic leukemia and highlight emerging investigational therapeutic options.

Results of a phase II study of lenalidomide and rituximab for refractory/relapsed chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is an incurable disease in need of new therapeutic strategies. The immunomodulatory agent, lenalidomide, has shown activity as salvage therapy for CLL. In this phase II trial, we combined lenalidomide with rituximab in 25 patients (range, 41-79) with refractory/relapsed CLL. Lenalidomide was administered orally on escalating doses, with cycle 1 doses of 2.5mg daily on days 1-7, 5mg on days 8-14, and 10mg on days 15-21 followed by 7days off. On cycle 2 and beyond, lenalidomide was administered at 20mg daily on days 1-21. Rituximab was administered at 375mg/m(2) intravenously on a weekly basis for the first cycle starting on day 15 for 4 doses, with each cycle being 28days. Treatment was continued until disease progression or toxicity. Overall response rate was 45.8% on intent-to-treat and 61.1% in evaluable patients (all partial responses). Median time to treatment failure was 14.3 months for evaluable patients, and median overall survival was not reached. The most common grade 3/4 toxicity was neutropenia (72% of patients). The most common nonhematologic toxicity was infection (29% of patients). Lenalidomide combined with rituximab showed activity in heavily treated refractory CLL with an acceptable toxicity profile.

Sequential ofatumumab and lenalidomide for the treatment of relapsed and refractory chronic lymphocytic leukemia and small lymphocytic lymphoma

Ofatumumab is a fully human anti-CD20 monoclonal antibody with enhanced antibody dependent and complement dependent cytotoxicity. Lenalidomide induces T cell and natural killer (NK) cell activation and in vitro enhances clearance of chronic lymphocytic leukemia (CLL) cells by monoclonal antibodies. We performed a multi-center, phase 2 trial of sequential treatment with ofatumumab and lenalidomide in patients with advanced, relapsed and refractory (R/R) CLL, consisting of ofatumumab 2000 mg intravenously on day 1 and lenalidomide 10 mg on days 8-28, for up to six cycles. Twenty-one subjects were included with median age of 63 years and two prior lines of therapy. The overall response rate was 47.6% and 23.8% had stable disease. Median overall survival was 21.5 months. Neutropenia and thrombocytopenia were the most frequent adverse events. Tumor flare reaction occurred in 43% of subjects. Intracycle sequential ofatumumab plus lenalidomide is active in high-risk R/R CLL and well tolerated except for frequent cytopenias.

Lenalidomide treatment and prognostic markers in relapsed or refractory chronic lymphocytic leukemia: data from the prospective, multicenter phase-II CLL-009 trial

Efficacy of lenalidomide was investigated in 103 patients with relapsed/refractory chronic lymphocytic leukemia (CLL) treated on the prospective, multicenter randomized phase-II CLL-009 trial. Interphase cytogenetic and mutational analyses identified TP53 mutations, unmutated IGHV, or del(17p) in 36/96 (37.5%), 68/88 (77.3%) or 22/92 (23.9%) patients. The overall response rate (ORR) was 40.4% (42/104). ORRs were similar irrespective of TP53 mutation (36.1% (13/36) vs 43.3% (26/60) for patients with vs without mutation) or IGHV mutation status (45.0% (9/20) vs 39.1% (27/68)); however, patients with del(17p) had lower ORRs than those without del(17p) (21.7% (5/22) vs 47.1% (33/70); P=0.049). No significant differences in progression-free survival and overall survival (OS) were observed when comparing subgroups defined by the presence or absence of high-risk genetic characteristics. In multivariate analyses, only multiple prior therapies (⩾3 lines) significantly impacted outcomes (median OS: 21.2 months vs not reached; P=0.019). This analysis indicates that lenalidomide is active in patients with relapsed/refractory CLL with unfavorable genetic profiles, including TP53 inactivation or unmutated IGHV. (ClinicalTrials.gov identifier: NCT00963105).

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

Chronic lymphocytic leukemia (CLL) is a disease of marked clinical heterogeneity, and while some patients have a normal life expectancy, others develop rapidly progressive disease shortly after diagnosis. The current standard for upfront treatment of CLL is chemoimmunotherapy for younger fit patients, FCR (fludarabine, cyclophosphamide, and rituximab) being the prototype. For older patients, BR (bendamustine and rituximab) exhibits excellent activity with decreased toxicity. For the frailest patients, CD20 monoclonal antibodies with or without chlorambucil have proven to be efficacious. The novel oral kinase inhibitors ibrutinib and idelalisib are FDA-approved in the relapsed/refractory setting, and ibrutinib is approved upfront for those with del(17p). These drugs have produced long-term durable responses in the relapsed/refractory setting, and studies are underway using these as single agent upfront or in combination with both chemotherapy and monoclonal antibodies. Here, we review standard upfront therapies and new agents and combinations that are on the horizon for 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.

Bendamustine + rituximab chemoimmunotherapy and maintenance lenalidomide in relapsed, refractory chronic lymphocytic leukaemia and small lymphocytic lymphoma: A Wisconsin Oncology Network Study

Bendamustine + rituximab (BR) has demonstrated high response rates in relapsed/refractory (R/R) chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma (SLL). However, progression-free survival (PFS) after BR is <18 months. This study was designed to determine if maintenance lenalidomide after BR induction could improve PFS in R/R CLL/SLL. Thirty-four patients with R/R CLL/SLL who had received 1-5 prior chemotherapy regimens were treated with 6 cycles of BR induction. Patients achieving at least a minor response received twelve 28-d cycles of lenalidomide 5-10 mg/d. The primary endpoint was PFS. The median age was 67 years, with a median of 2 prior therapies. Eleven patients had confirmed presence of 17p and/or 11q deletions. Twenty-five (74%) completed 6 cycles of induction BR (response rate 56%). Nineteen (56%) patients received maintenance lenalidomide; only 6 patients completed the intended 12 cycles, highlighting the limited feasibility of lenalidomide in this setting, primarily due to haematological and infectious toxicities. The observed median PFS of 18·3 months is not significantly different from that of BR induction in R/R CLL/SLL without maintenance therapy (15·2 months). It is possible that lenalidomide maintenance may be more feasible and effective in the front-line setting, which is being tested in an ongoing trial (NCT01754857).

Immunotherapy in Chronic Lymphocytic Leukaemia (CLL)

Chronic lymphocytic leukaemia (CLL) is well known to generate impaired immune responses in the host, with the malignant clone residing in well-vascularized tissues and circulating in peripheral blood but also in close proximity to effector cells that are capable, if activated appropriately, of eliciting a cytotoxic response. These, combined with the fact that this is frequently a condition affecting older patients with co-morbidities often unfit for many "traditional" cytotoxic agents with their significant associated toxicities, make CLL an ideal candidate for the development of immunotherapy. The impressive results seen with the addition of a monoclonal antibody, rituximab, to a chemotherapy backbone, for example, is testament to how effective harnessing an immune-mediated response in CLL can be. This review serves to outline the available arsenal of immunotherapies-past and present-demonstrated to have potential in CLL with some perspectives on how the landscape in this disease may evolve in the future.

Tumor lysis syndrome in the era of novel and targeted agents in patients with hematologic malignancies: a systematic review

Effective new treatments are now available for patients with hematologic malignancies. However, their propensity to cause tumor lysis syndrome (TLS) has not been systematically examined. A literature search identified published Phase I-III clinical trials of monoclonal antibodies (otlertuzumab, brentuximab, obinutuzumab, ibritumomab, ofatumumab); tyrosine kinase inhibitors (alvocidib [flavopiridol], dinaciclib, ibrutinib, nilotinib, dasatinib, idelalisib, venetoclax [ABT-199]); proteasome inhibitors (oprozomib, carfilzomib); chimeric antigen receptor (CAR) T cells; and the proapoptotic agent lenalidomide. Abstracts from major congresses were also reviewed. Idelalisib and ofatumumab had no reported TLS. TLS incidence was ≤5 % with brentuximab vedotin (for anaplastic large-cell lymphoma), carfilzomib and lenalidomide (for multiple myeloma), dasatinib (for acute lymphoblastic leukemia), and oprozomib (for various hematologic malignancies). TLS incidences were 8.3 and 8.9 % in two trials of venetoclax (for chronic lymphocytic leukemia [CLL]) and 10 % in trials of CAR T cells (for B-cell malignancies) and obinutuzumab (for non-Hodgkin lymphoma). TLS rates of 15 % with dinaciclib and 42 and 53 % with alvocidib (with sequential cytarabine and mitoxantrone) were seen in trials of acute leukemias. TLS mitigation was employed routinely in clinical trials of alvocidib and lenalidomide. However, TLS mitigation strategies were not mentioned or stated only in general terms for many studies of other agents. The risk of TLS persists in the current era of novel and targeted therapy for hematologic malignancies and was seen to some extent with most agents. Our findings underscore the importance of continued awareness, risk assessment, and prevention to reduce this serious potential complication of effective anticancer therapy.

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.