A phase II trial of lenalidomide plus rituximab in previously untreated follicular non-Hodgkin's lymphoma (NHL): CALGB 50803 (Alliance)

The progress of novel strategies on immune-based therapy in relapsed or refractory diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) can be cured with standard front-line immunochemotherapy, whereas nearly 30-40% of patients experience refractory or relapse. For several decades, the standard treatment strategy for fit relapsed/refractory (R/R) DLBCL patients has been high-dose chemotherapy followed by autologous hematopoietic stem cell transplant (auto-SCT). However, the patients who failed in salvage treatment or those ineligible for subsequent auto-SCT have dismal outcomes. Several immune-based therapies have been developed, including monoclonal antibodies, antibody-drug conjugates, bispecific T-cell engaging antibodies, chimeric antigen receptor T-cells, immune checkpoint inhibitors, and novel small molecules. Meanwhile, allogeneic SCT and radiotherapy are still necessary for disease control for fit patients with certain conditions. In this review, to expand clinical treatment options, we summarize the recent progress of immune-related therapies and prospect the future indirections in patients with R/R DLBCL.

Tisagenlecleucel: CAR-T cell therapy for adult patients with relapsed or refractory follicular lymphoma

INTRODUCTION

Tisagenlecleucel (tisa-cel) is an anti CD19 CAR-T therapy that has demonstrated clinical activity in R/R large B-cell lymphoma and R/R B-cell acute lymphoblastic leukemia. It showed particularly high efficacy in R/R follicular lymphoma (FL) with a manageable toxicity profile. The pivotal ELARA study in R/R FL confirmed these findings and led to the FDA approval of tisa-cel in R/R FL after two lines of systemic therapies.

AREAS COVERED

We start with an introduction of FL and the current treatment landscape with emphasis on the R/R setting. We review the role of CAR-T in R/R FL with focus on currently available products. We describe the ELARA study at a high level to give a perspective of the patient population that was treated. Finally, we discuss aspects related to product selection and whether bispecific antibodies will challenge the role of CAR-T in FL given their similar efficacy.

EXPERT OPINION

Tisa-cel is a highly effective therapy for heavily pretreated R/R FL with a toxicity profile that is low grade and manageable. Durable remissions (including high-risk patients) are seen in the pivotal ELARA study. Clinicians should consider early referral of R/R FL patients for assessment and discussion.

Follicular lymphoma: 2023 update on diagnosis and management

DISEASE OVERVIEW

Follicular lymphoma (FL) is generally an indolent B cell lymphoproliferative disorder of transformed follicular center B cells. FL is characterized by diffuse lymphadenopathy, bone marrow involvement, and splenomegaly. Extranodal involvement is less common. Cytopenias are relatively common but constitutional symptoms of fever, night sweats, and weight loss are uncommon in the absence of transformation to diffuse large B cell lymphoma.

DIAGNOSIS

The diagnosis is based on histology from a biopsy of a lymph node or other affected tissue. Incisional biopsy is preferred over needle biopsies in order to give adequate tissue to assign grade and assess for transformation. Immunohistochemical staining is positive in virtually all cases for cell surface CD19, CD20, CD10, and monoclonal immunoglobulin, as well as cytoplasmic expression of bcl-2 protein. The overwhelming majority of cases have the characteristic t(14;18) translocation involving the IgH/bcl-2 genes.

RISK STRATIFICATION

The Follicular Lymphoma International Prognostic Index (FLIPI) uses five independent predictors of inferior survival: age >60 years, hemoglobin <12 g/dL, serum LDH > normal, Ann Arbor stage III/IV, number of involved nodal areas >4. The presence of 0-1, 2, and ≥3 adverse factors defines low, intermediate, and high-risk disease. There are other clinical prognostic models but the FLIPI remains the most common. Other factors such as time to relapse of less than 2 years from chemoimmunotherapy and specific gene mutations may also be useful for prognosis. Regardless of the prognostic model used, modern therapies have demonstrably improved prognosis.

RISK-ADAPTED THERAPY

Observation continues to be appropriate for asymptomatic patients with low bulk disease and no cytopenias. There is no overall survival (OS) advantage for early treatment with either chemotherapy or single-agent rituximab. For patients needing therapy, most patients are treated with chemoimmunotherapy, which has improved overall response rates (ORR), DOR, and OS. Randomized studies have shown additional benefits for maintenance of rituximab. Lenalidomide was non-inferior to chemoimmunotherapy in a randomized front-line study and, when combined with rituximab, was superior to rituximab alone in relapsed FL. Kinase inhibitors, stem cell transplantation (SCT), and chimeric antigen receptor T cells (CAR-T) are also considered for recurrent disease.

Chicken-derived CD20 antibodies with potent B-cell depletion activity

We report four novel anti-human CD20 (hCD20) monoclonal antibodies (mAbs) discovered from a phylogenetically distant species-chickens. The chicken-human chimaeric antibodies exhibit at least 10-fold enhanced antibody-dependent cellular cytotoxicity (ADCC) and 4-8-fold stronger complement-dependent cytotoxicity (CDC) relative to the clinically used mouse-human chimaeric anti-hCD20 antibody rituximab (RTX). Thus, to our knowledge these mAbs are the first to significantly outperform RTX in both Fc-mediated mechanisms of action. The antibodies show 20-100-fold superior depletion of B cells in whole blood from healthy humans relative to RTX and retain efficacy in vivo. One of the mAbs, AC1, can bind mouse CD20, indicating specificity for a novel hCD20 epitope inaccessible to current (mouse-derived) anti-hCD20 mAbs. A humanized version of one antibody, hAC11-10, was created by complementarity-determining region (CDR) grafting into a human variable region framework and this molecule retained the ADCC, in vitro human whole-blood B-cell depletion, and in vivo lymphoma cell depletion activities of the parent. These mAbs represent promising monotherapy candidates for improving upon current less-than-ideal clinical outcomes in lymphoid malignancies and provide an arsenal of biologically relevant molecules for the development of next-generation CD20-mediated immunotherapies including bispecific T-cell engagers (BiTE), antibody-drug conjugates (ADC) and chimaeric antigen receptor-engineered T (CAR-T) cells.

Chinese expert consensus on oral drugs for the treatment of mature B-cell lymphomas (2020 edition)

Oral drugs such as ibrutinib play an important role in the treatment of mature B-cell lymphoma (BCL) due to their reliable efficacy, manageable safety, high accessibility, and convenience for use. Still, no guidelines or consensus focusing on oral drug therapies for BCL is available. To provide a reference of oral agent-based treatment for mature BCL, a panel of experts from the Lymphocyte Disease Group, Chinese Society of Hematology, Chinese Medical Association conducted an extensive discussion and reached a consensus on oral drugs for Chinese BCL patients on the basis of the current application status of oral drugs in China, combined with the latest authoritative guidelines in the world and current research reports. This consensus reviewed the application of oral drugs in the treatment of BCL and the latest research and provided appropriate recommendations on the use of oral drugs for indolent or aggressive BCL patients. With the deepening of research and the development of standardized clinical applications, oral medications will bring better treatment to BCL patients, enabling more patients to benefit from them.

Six-Year Results From RELEVANCE: Lenalidomide Plus Rituximab (R2) Versus Rituximab-Chemotherapy Followed by Rituximab Maintenance in Untreated Advanced Follicular Lymphoma

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.

The RELEVANCE trial (ClinicalTrials.gov identifier: NCT01650701) showed that lenalidomide plus rituximab (R²) provided similar efficacy to rituximab plus chemotherapy (R-chemo) in patients with advanced-stage, previously untreated follicular lymphoma (FL). We report the second interim analysis of the RELEVANCE trial after 6 years of follow-up. Patients with previously untreated grade 1-3a FL were assigned 1:1 to R² or R-chemo, followed by rituximab maintenance. Coprimary end points were complete response (confirmed/unconfirmed) at week 120 and progression-free survival (PFS). At median follow-up of 72 months, 6-year PFS was 60% and 59% for R² and R-chemo, respectively (hazard ratio = 1.03 [95% CI, 0.84 to 1.27]). Six-year overall survival was estimated to be 89% in both groups. Median PFS and overall survival were not reached in either group. Overall response after progression was 61% and 59%, and 5-year estimated survival rate after progression was 69% and 74% in the R² and R-chemo groups, respectively. The transformation rate per year in the R² and R-chemo groups was 0.68% and 0.45%, and secondary primary malignancies occurred in 11% and 13% (P = .34), respectively. No new safety signals were observed. R² continues to demonstrate comparable, durable efficacy and safety versus R-chemo in previously untreated patients with FL and provides an acceptable chemo-free alternative.

Orelabrutinib Combined With Lenalidomide and Immunochemotherapy for Relapsed/Refractory Primary Central Nervous System Lymphoma: A Retrospective Analysis of Case Series

Background

Relapsed/refractory (r/r) primary central nervous system lymphoma (PCNSL) is an intractable situation without sound treatment. Bruton’s tyrosine kinase (BTK) represents an attractive drug target in PCNSL. Orelabrutinib is a new-generation BTK inhibitor with high cerebrospinal fluid (CSF) concentration. This study aimed to evaluate the efficacy and safety of orelabrutinib-containing combination therapy in patients with r/r PCNSL.

Methods

We retrospectively analyzed r/r PCNSL patients who received combination therapy with rituximab, high-dose methotrexate, temozolomide, orelabrutinib and lenalidomide, and further explored the relationship between the efficacy and genetic characteristics.

Results

A total of fifteen patients were included in this retrospective study. The overall response rate (ORR) was 86.7%, the complete remission (CR) rate was 73.3% and the disease control rate (DCR) was 93.3%. Among 13 responders, 9 patients are still receiving oral orelabrutinib and lenalidomide. The most common adverse event (AEs) was transaminase increase (66.7%). No grade 4 AE or drug-related death was reported. Genomic sequencing showed that patients who responded to orelabrutinib had abnormal NF-κB activation, while those who had no response were mainly enriched with transcriptional misregulation. Patients who had mutations in TLR, BCR, or NF-κB pathway achieved complete or partial response to the orelabrutinib-containing therapy. Moreover, the blood and cerebrospinal fluid circulating tumor DNA (ctDNA) were closely associated with tumor recurrence and treatment response and sustained tumor responses correlated with the clearance of ctDNA.

Conclusion

Orelabrutinib-containing regimen was effective and well-tolerated in patients with r/r PCNSL. Genome sequencing of tumor samples could help to screen patients who may respond to the orelabrutinib-containing regimen, and liquid biopsy may contribute to tracing tumor burden and monitoring treatment response.

Oncological Treatment-Related Fatigue in Oncogeriatrics: A Scoping Review

Simple Summary

Fatigue in older patients has multiple etiologies, as this symptom may be cancer-related, treatment-related, age-related, or part of frailty syndrome. Physicians need to identify this symptom and understand its risk factors but also evaluate the risk/benefit ratio of cancer treatments considering the risk of impairing the patient’s quality of life. This scoping review was aimed to present the level of information currently available on any-grade fatigue and grade 3 or more fatigue for each cancer treatment regimen, either in general or in older populations, for the most prevalent tumors.

Abstract

Fatigue is a highly prevalent symptom in both cancer patients and the older population, and it contributes to quality-of-life impairment. Cancer treatment-related fatigue should thus be included in the risk/benefit assessment when introducing any treatment, but tools are lacking to a priori estimate such risk. This scoping review was designed to report the current evidence regarding the frequency of fatigue for the different treatment regimens proposed for the main cancer indications, with a specific focus on age-specific data, for the following tumors: breast, ovary, prostate, urothelium, colon, lung and lymphoma. Fatigue was most frequently reported using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) versions 3 to 5. A total of 324 regimens were analyzed; data on fatigue were available for 217 (67%) of them, and data specific to older patients were available for 35 (11%) of them; recent pivotal trials have generally reported more fatigue grades than older studies, illustrating increasing concern over time. This scoping review presents an easy-to-understand summary that is expected to provide helpful information for shared decisions with patients regarding the anticipation and prevention of fatigue during each cancer treatment.

Treatment of indolent lymphoma

Treatment of indolent lymphoma has improved significantly in recent decades since the advent of rituximab (anti-CD20 monoclonal antibody). Although, some patients with limited disease can be cured with radiation therapy alone, most patients experience disease progression and recurrence during follow-up despite early initiation of treatment. Thus, watch-and-wait is still regarded the standard for asymptomatic patients. Patients with indolent lymphoma have a significant heterogeneity in terms of tumor burden, symptoms (according to anatomical sites) and the need for instant therapy. Therefore, the initiation of treatment and treatment option should be decided with a clear goal in each patient according to the need for therapy and clinical benefits with the chosen treatment. In this review, we cover the current treatment of follicular lymphoma and marginal zone lymphoma.

SIRPα+ macrophages are increased in patients with FL who progress or relapse after frontline lenalidomide and rituximab

Chemoimmunotherapy is an effective treatment strategy for patients with FL who relapse after frontline R².

SIRPα⁺ and CSF1R⁺macrophages are increased in FL patients who relapse after frontline R².

Limited data exist regarding the outcome of patients with follicular lymphoma (FL) who relapse or progress after frontline lenalidomide and rituximab (R²). Moreover, mechanisms of resistance to R² in FL remain unclear, with increased protumoral macrophages suspected as a major contributory culprit to this phenomenon. This retrospective study analyzed the outcome of patients with advanced-stage FL grade 1 to 3A who relapsed or progressed after frontline R². A multiplex immunofluorescence macrophage panel, including CD47, CD14, CD68, CD115 (also known as colony-stimulating factor 1 receptor [CSF1R]), CD163, CD172a (also known as signal regulatory protein α [SIRPα]), and CD274 (also known as programmed cell death-ligand 1 [PDL1]), was used to stain tissue biopsy specimens collected before initiation of R² and at the time of progression. Among 156 patients with advanced-stage FL treated with frontline R², 33 (21%) relapsed or progressed and required second-line therapy, after a median of 33 months (range, 1-122 months). Second-line therapy was chemoimmunotherapy in 16 (48%) patients and other therapy in 17 (52%). The overall response rate was 78%, and complete response rate was 72%. Median progression-free survival was significantly longer in patients who received chemoimmunotherapy compared with other therapy (99 vs 25 months; P = .004). Three macrophage populations were significantly increased in tissue samples collected at progression compared with before frontline treatment: CD68⁺CD115⁺ (P = .02), CD68⁺CD115⁺CD172a⁺ (P = .02), and CD68⁺CD163⁺CD172a⁺ (P = .01). Chemoimmunotherapy is an effective treatment strategy for patients with FL who relapse after frontline R². Therapies targeting specific macrophage populations may yield novel approaches for improving outcomes with frontline R².

Concurrent lung adenocarcinoma and bladder diffuse large B-cell lymphoma: a case report and literature review

Lung adenocarcinoma is one of the most common solid tumors, and diffuse large B-cell lymphoma (DLBCL) is the most common histological subtype of adult non-Hodgkin’s lymphoma. Although extra-nodular lesions are frequently observed in patients with DLBCL, urinary bladder involvement is rare. We report the case of a 77-year-old woman with lung adenocarcinoma who was diagnosed with a second primary bladder DLBCL, 9 months after treatment with molecular targeted drugs. Simultaneous therapies for her lymphoma with lenalidomide and rituximab and a tyrosine kinase inhibitor therapy for her lung cancer were both effective. This result was consistent with previous reports suggesting that patients unable to tolerate intensive chemotherapy could benefit from targeted therapies. Current research into the use of lenalidomide for the treatment of lymphomas and solid tumors is promising in terms of exploring immunotherapy as an alternative option for patients with concurrent solid tumors and lymphomas who have poor tolerance to radiotherapy and chemotherapy.

Obinutuzumab plus lenalidomide (GALEN) in advanced, previously untreated follicular lymphoma in need of systemic therapy

Obinutuzumab and lenalidomide (GALEN) is an active immunomodulatory combination with a manageable safety profile in multiple types of lymphoma. We report efficacy and safety results for the phase 2 GALEN study in previously-untreated patients with advanced follicular lymphoma (FL). Eligible patients aged ≥ 18 years had ECOG PS ≤ 2, high-tumor burden, grade 1-3a FL. Induction treatment was obinutuzumab (1000 mg IV, days 8/15/22, cycle 1; day 1, cycles 2-6) plus lenalidomide (20 mg/day, days 1-21, cycle 1; days 2-22, cycles 2-6) for 6 cycles. Maintenance included obinutuzumab (1000 mg every 2 cycles) plus lenalidomide (10 mg, days 2-22) for ≤ 12 cycles (year 1) followed by obinutuzumab (1000 mg every 56 days) for 6 cycles (year 2). The primary endpoint was complete response rate (CRR) after induction per IWG 1999 criteria. From October 2015 to February 2017, 100 patients were enrolled. CRR after induction was 47% and overall response rate (ORR) 92%. Post-hoc analyses per 2014 Lugano classification including patients with missing bone marrow assessments identified an additional 13 patients fulfilling CRR criteria, resulting in a complete metabolic response of 80% and ORR of 94%. At a median follow-up of 3.7 years, 3-year progression-free and overall survival were 82% and 94%, respectively. The most common adverse event was neutropenia (48% any-grade; 47% grade ≥ 3) but only 2% of patients presented febrile neutropenia; others were mainly grade ≤ 2. No other specific grade ≥3 toxicity occurred at a frequency higher than 3%. Overall, these results demonstrated promising clinical efficacy for the chemo-free backbone obinutuzumab and lenalidomide in previously untreated, high tumor burden FL patients. Except for neutropenia, the safety profile of the combination is remarkable. The study was registered with ClinicalTrials.gov, number NCT01582776.

An Overview of Lenalidomide in Combination with Rituximab for the Treatment of Adult Patients with Follicular Lymphoma: The Evidence to Date

Follicular lymphoma (FL) is an indolent (low-grade) malignancy of B cells and is among the most common hematological cancers affecting adults. Its clinical presentation, natural course, and severity are highly variable. Management of FL depends on the clinical setting; most patients require multiple lines of treatment. Chemoimmunotherapy is the standard of care for FL patients needing treatment; however, alternative treatments are limited for refractory patients or those unfit for chemoimmunotherapy. Multiple alternatives to chemoimmunotherapy for FL are being developed, with some showing significant promise. Lenalidomide combination with rituximab (LR) is among the most successful and extensively studied novel approaches. LR has been compared head-to-head in clinical trials with rituximab monotherapy and chemoimmunotherapy in the frontline and to lenalidomide or rituximab monotherapy in the relapsed or refractory setting for the treatment of FL. Initial reports of these nine trials have been published in the last decade, and their long-term data will be available in the coming years. LR offered superior efficacy to either lenalidomide or rituximab monotherapy alone. The RELEVANCE trial compared the efficacy of LR with chemoimmunotherapy among 1030 FL patients and demonstrated similar efficacy with a different side effect profile. Myelosuppression, rash, and fatigue were among the significant adverse events. Most patients treated with LR received thromboprophylaxis. This paper aims to summarize and comment on the published evidence regarding LR treatment for FL through a literature review. The clinical trials will be presented in detail, and methodological differences complicating their comparisons will be discussed.

Long-term Follow-up and Correlative Analysis of Two Phase II Trials of Rituximab and Lenalidomide Followed by Continuous Lenalidomide in Untreated and Relapsed/Refractory Indolent Lymphoma

PURPOSE

Rituximab and lenalidomide are effective for previously untreated and relapsed/refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). However, long-term survival and predictive biomarkers are not well described.

PATIENTS AND METHODS

We conducted two phase II open-label trials involving 60 patients with previously untreated and R/R advanced-stage iNHL. Patients received lenalidomide and rituximab induction followed by continuous lenalidomide until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Correlative studies included plasma cytokine monitoring, flow cytometry of peripheral blood mononuclear cells (PBMC; days 0, 15, 30, and 60), and RNA sequencing (RNA-seq) of pretreatment tumor biopsies.

RESULTS

At a median follow-up of 63 months for previously untreated and 100 months for R/R, ORR was 82% for both. The 11 R/R patients who achieved complete remission remained in continuous remission for 16 to 141 months, thereafter. Median overall survival (OS) was not reached in the previously untreated and was 140 months (95% confidence interval, 53.4-140) in the R/R group. A mixed-effects linear regression model identified significant associations between Granzyme B⁺ (GranB⁺) CD8⁺ T cells and long-term complete response (LTCR; P = 5.3e-4). Furthermore, prior to start of therapy, treatment response could be predicted by B-cell and GranB⁺ CD8⁺ T-cell levels (% total lymphocytes).

CONCLUSIONS

Rituximab plus lenalidomide followed by continuous lenalidomide is effective with manageable toxicity in patients with previously untreated and R/R iNHL. This regimen produces durable remissions, even in heavily pretreated patients, with some lasting greater than 10 years. GranB⁺ CD8⁺ T cells, B cells, and plasma IFNγ allowed prediction of LTCR but need validation in larger trials.

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.

An Immune-Clinical Prognostic Index (ICPI) for Patients With De Novo Follicular Lymphoma Treated With R-CHOP/CHOP Chemotherapy

Purpose

Although the role of tumor-infiltrating T cells in follicular lymphoma (FL) has been reported previously, the prognostic value of peripheral blood T lymphocyte subsets has not been systematically assessed. Thus, we aim to incorporate T-cell subsets with clinical features to develop a predictive model of clinical outcome.

Methods

We retrospectively screened a total of 1,008 patients, including 252 newly diagnosed de novo FL patients with available peripheral blood T lymphocyte subsets who were randomized to different sets (177 in the training set and 75 in the internal validation set). A nomogram and a novel immune-clinical prognostic index (ICPI) were established according to multivariate Cox regression analysis for progression-free survival (PFS). The concordance index (C-index), Akaike’s information criterion (AIC), and likelihood ratio chi-square were employed to compare the ICPI’s discriminatory capability and homogeneity to that of FLIPI, FLIPI2, and PRIMA-PI. Additional external validation was performed using a dataset (n = 157) from other four centers.

Results

In the training set, multivariate analysis identified five independent prognostic factors (Stage III/IV disease, elevated lactate dehydrogenase (LDH), Hb <120g/L, CD4+ <30.7% and CD8+ >36.6%) for PFS. A novel ICPI was established according to the number of risk factors and stratify patients into 3 risk groups: high, intermediate, and low-risk with 4-5, 2-3, 0-1 risk factors respectively. The hazard ratios for patients in the high and intermediate-risk groups than those in the low-risk were 27.640 and 2.758. The ICPI could stratify patients into different risk groups both in the training set (P < 0.0001), internal validation set (P = 0.0039) and external validation set (P = 0.04). Moreover, in patients treated with RCHOP-like therapy, the ICPI was also predictive (P < 0.0001). In comparison to FLIPI, FLIPI2, and PRIMA-PI (C-index, 0.613-0.647), the ICPI offered adequate discrimination capability with C-index values of 0.679. Additionally, it exhibits good performance based on the lowest AIC and highest likelihood ratio chi-square score.

Conclusions

The ICPI is a novel predictive model with improved prognostic performance for patients with de novo FL treated with R-CHOP/CHOP chemotherapy. It is capable to be used in routine practice and guides individualized precision therapy.

Lenalidomide triggers T-cell effector functions in vivo in patients with follicular lymphoma

The immunomodulatory drug lenalidomide is used in patients with follicular lymphoma (FL) with the aim of stimulating T-cell antitumor immune response. However, little is known about the effects of lenalidomide on T-cell biology in vivo in patients with FL. We thus undertook an extensive longitudinal immunologic study, including phenotypic, transcriptomic, and functional analyses, on 44 first-line and 27 relapsed/refractory patients enrolled in the GALEN trial (Obinutuzumab Combined With Lenalidomide for Relapsed or Refractory Follicular B-Cell Lymphoma) to test the efficacy of lenalidomide and obinutuzumab combination in patients with FL. Lenalidomide rapidly and transiently induced an activated T-cell phenotype, including HLA-DR, Tim-3, CD137, and programmed cell death protein 1 (PD-1) upregulation. Furthermore, sequential RNA-sequencing of sorted PD-1+ and PD-1- T-cell subsets revealed that lenalidomide triggered a strong enrichment for several gene signatures related to effector memory T-cell features, including proliferation, antigen receptor signaling, and immune synapse restoration; all were validated at the phenotypic level and with ex vivo functional assays. Correlative analyses pinpointed a negative clinical impact of high effector T-cell and regulatory T-cell percentages before and during treatment. Our findings bring new insight in lenalidomide mechanisms of action at work in vivo and will fuel a new rationale for the design of combination therapies.

Chemotherapy-Free Management of Follicular and Marginal Zone Lymphoma

Many patients with follicular (FL) or marginal zone lymphoma (MZL) are not eligible to receive immunochemotherapy due to advanced age or comorbidities. Recent innovations in the treatment of these indolent lymphomas provide options for multiple lines of chemotherapy-free management. More research is needed to determine which older patients are best served by a chemotherapy-free approach in the context of geriatric vulnerabilities. In the first line, regardless of disease burden, rituximab monotherapy can provide high rates of disease control with minimal toxicity, while judicious use of brief maintenance extends the duration of response. Radioimmunotherapy using ibritumomab tiuxetan is an effective and safe post-rituximab consolidation for older patients who have <25% bone marrow involvement. The combination of rituximab and lenalidomide, although “chemotherapy-free”, does not improve tolerability over immunochemotherapy. However, studies support lower doses and shorter duration of lenalidomide exposure as a means to improve safety without materially compromising efficacy for older individuals. Extranodal MZL can often be effectively controlled with low-dose radiation therapy, and splenic MZL has excellent outcomes with rituximab monotherapy. For many patients with relapsed FL/MZL, simple retreatment with anti-CD20 antibodies will prove sufficient. Other currently available options for relapsed/refractory disease include ibritumomab tiuxetan, lenalidomide with rituximab, umbralisib as a potentially less toxic PI3K inhibitor, ibrutinib (for MZL), and tazemetostat (for FL, especially with EZH2 mutation). Emerging data with novel forms of immunotherapy (antibody-drug conjugates like polatuzumab vedotin or loncastuximab tesirine; T-cell-engaging bispecific antibodies like mosunetuzumab or epcoritamab; and chimeric antigen receptor CAR T-cells like axicabtagene ciloleucel) suggest that immune-directed approaches can produce very high and potentially durable responses in FL/MZL with limited toxicities, further obviating the need for chemotherapy.

When to Use Targeted Therapy for the Treatment of Follicular Lymphoma

PURPOSE OF REVIEW

Follicular lymphoma is a common indolent non-Hodgkin lymphoma with survival improving in the modern era. Despite favorable responses and improving remission duration, FL remains largely incurable with patterns of relapsing and remitting disease with many patients requiring multiple lines of therapy. As our understanding of the malignant B-cell biology evolves, more targeted therapies have emerged for the treatment of follicular lymphoma.

RECENT FINDINGS

Targeted therapies entering the treatment landscape of follicular lymphoma include lenalidomide in combination with rituximab based on the randomized AUGMENT. Tazemetostat, an EZH2 inhibitor, joins the list of targeted therapies approved based on single-arm phase 2 studies in the relapsed setting. There are three PI3K inhibitors currently approved and more under development. Herein, I will review the available evidence that supports the use of targeted therapy across the disease course of follicular lymphoma.

Biomarkers for Risk Stratification in Patients With Previously Untreated Follicular Lymphoma Receiving Anti-CD20-based Biological Therapy

Follicular lymphoma (FL) is an indolent B-cell neoplasm of germinal center origin. Standard treatment regimens consist of anti-CD20 therapy with or without chemotherapy. While high response rates to initial therapy are common, patients ultimately relapse or have progressive disease. Clinical risk factors such as the Follicular Lymphoma International Prognostic Index (FLIPI) have been identified, but there is a need for prognostic and predictive biomarkers. We studied markers of lymphoma cells and tumor microenvironment by immunohistochemistry in tissue samples from patients enrolled in 1 of 4 phase 2 trials of anti-CD20-based biological therapy for previously untreated grades 1 to 2 or 3A FL. Results were correlated with progression-free survival (PFS) and PFS status at 24 months. The 4 trials included 238 patients (51.1% male, median age: 55 y) with stage III, IV, or bulky stage II disease. By FLIPI, 24.6% had low-risk, 56.8% had intermediate-risk, and 18.6% had high-risk disease. The outcome differed significantly for patients treated with lenalidomide and rituximab (CALGB 50803) compared with the other 3 trials (median: PFS not reached vs. 3.0 y, hazard ratio=3.47, 95% confidence interval: 2.11-5.72); therefore, data were stratified by clinical trial (CALGB 50803 vs. all others) and adjusted for FLIPI risk group. Among 154 patients with available tissue, interfollicular BCL6 positivity, interfollicular CD10 positivity, and elevated Ki67 proliferation index ≥30% within neoplastic follicles were each associated with inferior PFS and a high risk of the early event by PFS status at 24 months. We identify promising biomarkers for FL risk stratification that warrant further validation in phase 3 trials.

Lenalidomide in follicular lymphoma

Lenalidomide is an immunomodulatory drug approved in the United States for use with rituximab in patients with relapsed/refractory follicular lymphoma. We reviewed data from trials addressing the safety and efficacy of lenalidomide alone and in combination with rituximab as a first-line therapy and as a treatment of patients with relapsed/refractory follicular lymphoma. Lenalidomide-rituximab has been demonstrated to be an effective chemotherapy-free therapy that improves upon single-agent rituximab and may become an alternative to chemoimmunotherapy.

ADCs, BiTEs, CARs, and Small Molecules: A New Era of Targeted Therapy in Non-Hodgkin Lymphoma

Novel immunotherapies and small molecular inhibitors are transforming our approach to previously treated and newly diagnosed patients across the spectrum of non-Hodgkin lymphomas (NHLs). Anti-CD19 CAR T cells are now indicated for the treatment of relapsed/refractory aggressive B-cell lymphomas after at least two previous lines of therapy in which durable remissions are achieved in approximately 40% of previously incurable patients. Second-line chemoimmunotherapy remains the standard of care at first relapse, but poor outcomes with conventional treatment in this setting creates an appealing rationale for earlier use of CAR T cells, which is currently under investigation, along with even earlier use in selected high-risk patients in the frontline setting. Other emerging immunotherapies include antibody-drug conjugates (ADCs), such as polatuzumab vedotin for multiple-relapsed diffuse large B-cell lymphoma (DLBCL) in combination with bendamustine-rituximab. Multiple bispecific antibodies that bring malignant B cells in contact with effector T cells appear promising in early clinical trials and will likely emerge as off-the-shelf immunotherapy options. Chemotherapy-free small molecule-based regimens are increasingly available for mantle cell (MCLs) and follicular lymphomas (FLs). Bruton tyrosine kinase inhibitors (BTKi) now represent standard second-line therapy for MCL and are being investigated in combination and as initial therapy. Lenalidomide-rituximab is an active regimen in both FL and MCL and may be used in either relapsed/refractory or previously untreated disease. Three PI3K inhibitors are approved for multiple-relapsed FL and can induce durable remissions in patients with chemotherapy- and rituximab-refractory disease. Additional emerging targeted therapies include BCL2 inhibition in MCL and EZH2 inhibition in FL.

Immunotherapy of lymphomas

Lymphoid malignancies typically promote an infiltrate of immune cells at sites involved by the disease. While some of the immune cells present in lymphoma have effector function, the immune system is unable to eradicate the malignant clone. Therapies that optimize immune function therefore have the potential to improve the outcome of lymphoma patients. In this Review, we discuss immunologic approaches that directly target the malignant cell as well as approaches to optimize both the innate and adaptive immune response to the tumor. While many of these therapies have shown single-agent activity, the future will clearly require thoughtful combinations of these approaches.

Initial report of a phase II study with R-FND followed by ibritumomab tiuxetan radioimmunotherapy and rituximab maintenance in patients with untreated high-risk follicular lymphoma

R-FND (rituximab, fludarabine, mitoxantrone, and dexamethasone) can induce molecular remissions in indolent lymphoma. The addition of ⁹⁰yttrium ibritumomab tiuxetan (⁹⁰YIT) radioimmunotherapy following first-line induction treatment in patients with advanced follicular lymphoma (FL) may improve remission rates. We now report 10-year follow-up results from our sequential treatment approach with an abbreviated regimen of R-FND followed by ⁹⁰YIT consolidation and rituximab maintenance. Forty-nine patients were enrolled; 47 received treatment. Patients had high-risk (FLIPI score ≥3) FL of grade 1-3A and stage III/IV with adequate hematologic function. Following R-FND, the complete and partial response rates were 91% and 8.5%, respectively. After ⁹⁰YIT consolidation, the CR rate increased to 97%. The 10-year PFS rate was 49%. The most common non-hematologic, grade 3 or 4 adverse events were fatigue, dyspnea, and myalgia. Five developed myelodysplastic syndrome (MDS). This treatment approach is most appropriate in FLIPI-based high-risk patients whose outlook with standard therapy is inadequate.

IMiDs New and Old

PURPOSE OF REVIEW

IMiDs are a class of biologic agents with immunomodulatory, anti-angiogenic, and direct anti-cancer activities. This review summarizes current data on clinical development and application of IMiDs in non-Hodgkin lymphoma (NHL) subtypes, focusing primarily on lenalidomide, with additional discussion on managing common side effects.

RECENT FINDINGS

Improved upon the prototype thalidomide, the second-generation compound lenalidomide has enhanced immunological and anti-cancer properties with fewer side effects, while next-generation small molecule cereblon/E3 ubiquitin ligase modulator CC-122 is in early clinical studies. Lenalidomide is FDA-approved for treatment of relapsed/refractory mantle cell lymphoma as a single agent, as well as in combination with rituximab for R/R follicular lymphoma and marginal zone lymphoma. In addition, numerous clinical trials of lenalidomide, as single agent, in combination with anti-CD20 antibodies, or in combination with chemoimmunotherapy regimens, have shown promise in aggressive and indolent NHL in both the upfront and relapsed/refractory setting. As clinical trials with lenalidomide continue to find success in both indolent and aggressive lymphomas, IMiDs are poised to be important building blocks for combinatorial strategies with antibodies, chemotherapy, novel target agents, and emerging immunotherapy involving immune checkpoint inhibitors and chimeric antigen receptor T cell (CAR-T) therapy. Delineation of treatment-specific and disease-specific biomarkers is an important research objective to gain insight into potential mechanisms of action, and to guide future clinical development.

Use of anti-CD20 therapy in follicular and marginal zone lymphoma: a review of the literature

The identification of the CD20 antigen in 1979 was the first step in what would become a therapeutic milestone opening the use of immunotherapy in hematological diseases. This protein is expressed on the surface of developing B cells, but not the early progenitors or mature plasma cells. In 1997, rituximab was approved by the Food and Drug Administration, and since then it has revolutionized the treatment of B-cell malignancies. It is used as a monotherapy and in combination, at induction, at relapsed, and also in maintenance. Indolent non-Hodgkin lymphomas are characterized by a long and non-aggressive course. In this group of lymphomas, rituximab represented a great therapeutic improvement, achieving lasting responses with few adverse effects. Nowadays, second-generation molecules are emerging that may have important advantages compared to rituximab, as well as biosimilars that represent an important cost-effective option.

The combination of ibrutinib and rituximab demonstrates activity in first-line follicular lymphoma

This phase 2 study evaluated the activity and safety of ibrutinib, a Bruton's tyrosine kinase inhibitor, plus rituximab in adults with previously untreated follicular lymphoma. Patients received once-daily ibrutinib 560 mg continuously plus once-weekly rituximab 375 mg/m2 for 4 weeks beginning Week 1 (Arm 1, n = 60) or Week 9 (following an 8-week ibrutinib lead-in) to explore biomarkers (Arm 2, n = 20). The primary endpoint was the best overall response rate (ORR). The median age was 58 years; most had an Eastern Cooperative Oncology Group Performance Status of 0 (74%) and Stage III/IV disease (84%). At a median study follow-up of 34 months in Arm 1 and 29 months in Arm 2, ORRs were 85% [95% confidence interval (CI) 73-93] and 75% (95% CI 51-91), respectively, with complete responses in 40% and 50%. The median duration of response was not reached in either arm; 30-month progression-free and overall survival rates were 67% and 97% (Arm 1) and 65% and 100% (Arm 2). The most common adverse events were fatigue, diarrhoea and nausea. Higher grade (Grade 3/4) haematological, haemorrhagic and cardiac events occurred infrequently. Ibrutinib plus rituximab was active and tolerable in first-line follicular lymphoma.

Management of Adverse Events From the Combination of Rituximab and Lenalidomide in the Treatment of Patients With Follicular and Low-Grade Non-Hodgkin Lymphoma

Frontline treatment for patients with indolent non-Hodgkin lymphoma often includes immunochemotherapy. Although the disease of most patients responds to initial treatment, relapse is common. Recent results from the phase 3 Augment trial showed that combining rituximab with the immunomodulatory drug lenalidomide (R²) significantly improved efficacy over rituximab monotherapy in patients with recurrent non-Hodgkin lymphoma. As a result of these data, R² was approved in the US (Food and Drug Administration) and Japan (Pharmaceuticals and Medical Devices Agency) for previously treated adult patients with follicular and marginal zone lymphoma; and by the European Medicine Agency and the Swiss Agency for Therapeutic Products (Swissmedic) for previously treated adult patients with follicular lymphoma. R² has also been studied as initial treatment, where results have been comparable, but not superior, to chemoimmunotherapy. The resulting expanded use of R² reinforces the need for a detailed review of its safety profile and management, as presented here. Tolerability of R² has been consistent among trials, with most adverse events (AEs) being predictable and manageable. Hematologic AEs, particularly grade 3/4 neutropenia; low-grade cutaneous reactions, such as rash; and gastrointestinal AEs represent the most common AEs associated with R². The general R² safety profile and optimal strategies for AE management are discussed.

Follicular lymphoma: 2020 update on diagnosis and management

DISEASE OVERVIEW

Follicular lymphoma (FL) is generally an indolent B cell lymphoproliferative disorder of transformed follicular center B cells. Follicular lymphoma is characterized by diffuse lymphadenopathy, bone marrow involvement, and splenomegaly. Extranodal involvement is less common. Cytopenias are relatively common but constitutional symptoms of fever, night sweats, and weight loss are uncommon in the absence of transformation to diffuse large B cell lymphoma.

DIAGNOSIS

The diagnosis is based on histology from a biopsy of a lymph node or other affected tissue. Incisional biopsy is preferred over needle biopsies in order to give adequate tissue to assign grade and assess for transformation. Immunohistochemical staining is positive in virtually all cases for cell surface CD19, CD20, CD10 and monoclonal immunoglobulin, as well as cytoplasmic expression of bcl-2 protein. The overwhelming majority of cases have the characteristic t(14;18) translocation involving the IgH/bcl-2 genes.

RISK STRATIFICATION

The Follicular Lymphoma International Prognostic Index (FLIPI) uses five independent predictors of inferior survival: age > 60 years, hemoglobin <12 g/dL, serum LDH > normal, Ann Arbor stage III/IV, number of involved nodal areas >4. The presence of 0-1, 2, and ≥ 3 adverse factors defines low, intermediate, and high-risk disease. There are other clinical prognostic models but the FLIPI remains the most common. Other factors such as time to relapse of less than 2 years from chemoimmunotherapy and specific gene mutations may also be useful for prognosis. Regardless of the prognostic model used, modern therapies have demonstrably improved prognosis.

RISK-ADAPTED THERAPY

Observation continues to be appropriate for asymptomatic patients with low bulk disease and no cytopenias. There is no overall survival advantage for early treatment with either chemotherapy or single agent rituximab. For patients needing therapy, most patients are treated with chemoimmunotherapy, which has improved response rates, duration of response and overall survival (OS). Randomized studies have shown additional benefit for maintenance rituximab. Lenalidomide was non-inferior to chemoimmunotherapy in a randomized front-line study and, when combined with rituximab, was superior to rituximab alone in relapsed FL. Kinase inhibitors, other immunotherapies, and stem cell transplantation (SCT) are also considered for recurrent disease.

Follicular lymphoma treatment patterns between 2000 and 2014: a SEER-Medicare analysis of elderly patients

Aim: Characterize follicular lymphoma (FL) treatment patterns among elderly patients using a dataset with longer follow-up time. Materials & methods: Using the linked Surveillance, Epidemiology and End Results-Medicare data, we identified patients diagnosed with FL between 2000 and 2013 with claims data until 2014. We investigated the treatments received and assigned them to lines of treatment. Results: We identified 10,238 elderly patients. Over a 4.7-year median follow-up, 78% of the patients received at least first-line treatment. Fewer individuals received second-line (47%) and third-line (30%) treatments. RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone), RCVP (rituximab, cyclophosphamide, vincristine and prednisolone) and rituximab monotherapy were the most common treatment regimens. Conclusion: One in five elderly patients did not receive FL-directed therapy. The most common treatment regimens were limited to RCHOP, RCVP and rituximab monotherapy.

Analysis of Japanese patients from the AUGMENT phase III study of lenalidomide + rituximab (R2) vs. rituximab + placebo in relapsed/refractory indolent non-Hodgkin lymphoma

Patients with indolent non-Hodgkin lymphoma (iNHL) typically respond to first-line immunochemotherapy, but relapse is common. Treatment options for relapsed iNHL include chemotherapy ± rituximab and rituximab monotherapy. Lenalidomide plus rituximab (R²) is an immunomodulatory regimen that enhances rituximab-mediated cytotoxicity and improves clinical activity in iNHL. AUGMENT was a double-blind phase III randomized trial of R² vs. rituximab + placebo (R-placebo) in patients with relapsed/refractory follicular lymphoma or marginal zone lymphoma who were not refractory to rituximab. The primary endpoint was progression-free survival (PFS). Data reported here focus on Japanese patients from AUGMENT and reflect 36 patients (n = 18, each group). PFS was superior in the R² group, HR = 0.32 (95% CI 0.11-0.96). Median PFS was not reached (95% CI 19.7-NE) in the R² group vs. 16.5 months (95% CI 11.3-30.6) in the R-placebo group. Grade 3/4 adverse events were more frequent in patients treated with R² (67%) than with R-placebo (22%), primarily attributable to increased neutropenia (50% vs 17%). R² resulted in significantly longer median PFS than R-placebo in Japanese patients with R/R iNHL, and the efficacy and the safety profile of R² were similar to those reported in the global population.

Follicular lymphoma

Follicular lymphoma (FL) is a systemic neoplasm of the lymphoid tissue displaying germinal centre (GC) B cell differentiation. FL represents ~5% of all haematological neoplasms and ~20-25% of all new non-Hodgkin lymphoma diagnoses in western countries. Tumorigenesis starts in precursor B cells and becomes full-blown tumour when the cells reach the GC maturation step. FL is preceded by an asymptomatic preclinical phase in which premalignant B cells carrying a t(14;18) chromosomal translocation accumulate additional genetic alterations, although not all of these cells progress to the tumour phase. FL is an indolent lymphoma with largely favourable outcomes, although a fraction of patients is at risk of disease progression and adverse outcomes. Outcomes for FL in the rituximab era are encouraging, with ~80% of patients having an overall survival of >10 years. Patients with relapsed FL have a wide range of treatment options, including several chemoimmunotherapy regimens, phosphoinositide 3-kinase inhibitors, and lenalidomide plus rituximab. Promising new treatment approaches include epigenetic therapeutics and immune approaches such as chimeric antigen receptor T cell therapy. The identification of patients at high risk who require alternative therapies to the current standard of care is a growing need that will help direct clinical trial research. This Primer discusses the epidemiology of FL, its molecular and cellular pathogenesis and its diagnosis, classification and treatment.

Indolent lymphomas: pushing the pace with novel agents

Chemoimmunotherapy has been a hallmark of treatment of indolent B-cell non-Hodgkin lymphomas for the past 2 decades, with high response rates seen but relapses nearly inevitable and patients spending, on average, 20 years on and off treatment. Treatment advances, then, should be aimed at maintaining efficacy while minimizing toxicity or at achieving cure. Improved understanding of the genetic and molecular features of these diseases, as well as of the interaction between the tumor cell and its immune microenvironment, has resulted in an accelerated expansion of tolerable treatment options for patients, with new combinations of therapy holding promise that definitive therapy in these diseases is possible. These drugs include immunomodulating agents such as lenalidomide, small-molecule inhibitors of the B-cell receptor signaling pathway such as ibrutinib and idelalisib, B-cell lymphoma 2 homology 3 mimetics such as venetoclax, and enhancer of zeste homolog 2 inhibitors such as tazemetostat. Therapies that improve the host immune response against the malignant B cell are also of great interest, given the durable remission seen after allogeneic stem cell transplant in these diseases, and immune checkpoint inhibitors, agonist antibodies against immunostimulatory T-cell receptors, antibody-drug conjugates, bispecific antibodies, and finally chimeric antigen receptor T cells are all being investigated, with promising early efficacy signals. These treatments may not necessarily replace chemotherapy but rather augment it in an attempt to improve quality of life and survival for these patients.

Current targeted therapies in lymphomas

Purpose

This article summarizes current targeted therapies that have received regulatory approval for the treatment of B- and T-cell lymphomas.

Summary

Over the last 20 years, new drug therapies for lymphomas of B cells and T cells have expanded considerably. Targeted therapies for B-cell lymphomas include: (1) monoclonal antibodies directed at the CD20 lymphocyte antigen, examples of which are rituximab, ofatumumab, and obinutuzumab; (2) gene transfer therapy, an example of which is chimeric antigen receptor–modified T-cell (CAR-T) therapy directed at the CD19 antigen expressed on the cell surface of both immature and mature B cells; and (3) small-molecule inhibitors (ibrutinib, acalabrutinib, copanlisib, duvelisib, and idelalisib) that target the B-cell receptor signaling pathway. Of note, brentuximab vedotin is an antibody–drug conjugate that targets CD30, another lymphocyte antigen expressed on the cell surface of both Hodgkin lymphoma (a variant of B-cell lymphoma) and some T-cell lymphomas. Although aberrant epigenetic signaling pathways are present in both B- and T-cell lymphomas, epigenetic inhibitors (examples include belinostat, vorinostat, and romidepsin) are currently approved by the Food and Drug Administration for T-cell lymphomas only. In addition, therapies that target the tumor microenvironment have been developed. Examples include mogamulizumab, bortezomib, lenalidomide, nivolumab, and pembrolizumab. In summary, the efficacy of these agents has led to the development of supportive care to mitigate adverse effects, due to the presence of on- or off-target toxicities.

Conclusion

The therapeutic landscape of lymphomas has continued to evolve. In turn, the efficacy of these agents has led to the development of supportive care to mitigate adverse effects, due to the presence of on- or off-target toxicities. Further opportunities are warranted to identify patients who are most likely to achieve durable response and reduce the risk of disease progression. Ongoing trials with current and investigational agents may further elucidate their place in therapy and therapeutic benefits.

Safety and Tolerability of Phosphatidylinositol-3-Kinase (PI3K) Inhibitors in Oncology

Activation of phosphatidylinositol-3-kinase (PI3K) and downstream signalling by AKT/mammalian target of rapamycin (mTOR) modulates cellular processes such as increased cell growth, cell proliferation and increased cell migration as well as deregulated apoptosis and oncogenesis. The PI3K/AKT/mTOR pathway (particularly Class I PI3K isoforms) is frequently activated in a variety of solid tumours and haematological malignancies, making PI3K an attractive therapeutic target in oncology. Inhibitors of PI3K also have the potential to restore sensitivity to other modalities of treatments when administered as part of combination regimens. Although many PI3K inhibitors have reached different stages of clinical development, only two (idelalisib and copanlisib) have been currently approved for use in the treatment of B cell lymphoma and leukaemias. While these two agents are effective clinically, their use is associated with a number of serious class-related as well as drug-specific adverse effects. Some of these are immune-mediated and include cutaneous reactions, severe diarrhoea with or without colitis, hepatotoxicity and pneumonitis. They also induce various metabolic abnormalities such as hyperglycaemia and hypertriglyceridaemia. Not surprisingly, therefore, many new PI3K inhibitors with a varying degree of target selectivity have been synthesised in expectations of improved safety and efficacy, and are currently under clinical investigations for use in a variety of solid tumours as well as haematological malignancies. However, evidence from early clinical trials, reviewed herein, suggests that these newer agents are also associated not only with class-related but also other serious and unexpected adverse effects. Their risk/benefit evaluations have resulted in a number of them being discontinued from further development. Cumulative experience with the use of PI3K inhibitors under development suggests that, compared with their use as monotherapy, combining them with other anticancer therapies may be a more effective strategy in improving current standard-of-care and clinical outcomes in cancers beyond haematological cancers. For example, combination of alpelisib with fulvestrant has recently demonstrated unexpectedly superior efficacy compared to fulvestrant alone. Furthermore, the immunomodulatory activity of PI3Kδ and PI3Kγ inhibitors also provides unexpected opportunities for their use in cancer immunotherapy, as is currently being tested in several clinical trials.

Short regimen of rituximab plus lenalidomide in follicular lymphoma patients in need of first-line therapy

The SAKK 35/10 phase 2 trial, developed by the Swiss Group for Clinical Cancer Research and the Nordic Lymphoma Group, compared the activity of rituximab vs rituximab plus lenalidomide in untreated follicular lymphoma patients in need of systemic therapy. Patients were randomized to rituximab (375 mg/m² IV on day 1 of weeks 1-4 and repeated during weeks 12-15 in responding patients) or rituximab (same schedule) in combination with lenalidomide (15 mg orally daily for 18 weeks). Primary end point was complete response (CR)/unconfirmed CR (CRu) rate at 6 months. In total, 77 patients were allocated to rituximab monotherapy and 77 to the combination (47% poor-risk Follicular Lymphoma International Prognostic Index score in each arm). A significantly higher CR/CRu rate at 6 months was documented in the combination arm by the investigators (36%; 95% confidence interval [CI], 26%-48% vs 25%; 95% CI, 16%-36%) and confirmed by an independent response review of computed tomography scans only (61%; 95% CI, 49%-72% vs 36%; 95% CI, 26%-48%). After a median follow-up of 4 years, significantly higher 30-month CR/CRu rates and longer progression-free survival (PFS) and time to next treatment (TTNT) were observed for the combination. Overall survival (OS) rates were similar in both arms (≥90%). Toxicity grade ≥3 was more common in the combination arm (56% vs 22% of patients), mainly represented by neutropenia (23% vs 7%). Addition of lenalidomide to rituximab significantly improved CR/CRu rates, PFS, and TTNT, with expected higher, but manageable toxicity. The excellent OS in both arms suggests that chemotherapy-free strategies should be further explored. This trial was registered at www.clinicaltrials.gov as #NCT01307605.

Targeting Biology in Non-Hodgkin Lymphoma

Chemotherapy nonspecifically affects all cells undergoing DNA replication and has severe side effects. Understanding of the biology of non-Hodgkin lymphomas has led to development of drugs that target specific lymphoma cell functions and tumor microenvironment. Targeted agents used in combination with chemotherapy pave the way to a chemotherapy-free world. These drugs target multiple oncogenic pathways and modulate the immune system, with better outcomes. Such combinations should be administered only in clinical trials. Incorporating studies of the biology and genetics of these tumors into therapeutic studies may lead to a chemotherapy-free world with improved outcomes and reduced toxicities.

Targeting PI3K in cancer: mechanisms and advances in clinical trials

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is one of the most important intracellular pathways, which can be considered as a master regulator for cancer. Enormous efforts have been dedicated to the development of drugs targeting PI3K signaling, many of which are currently employed in clinical trials evaluation, and it is becoming increasingly clear that PI3K inhibitors are effective in inhibiting tumor progression. PI3K inhibitors are subdivided into dual PI3K/mTOR inhibitors, pan-PI3K inhibitors and isoform-specific inhibitors. In this review, we performed a critical review to summarize the role of the PI3K pathway in tumor development, recent PI3K inhibitors development based on clinical trials, and the mechanisms of resistance to PI3K inhibition.

Combination lenalidomide-rituximab immunotherapy activates anti-tumour immunity and induces tumour cell death by complementary mechanisms of action in follicular lymphoma

Chemotherapy plus rituximab has been the mainstay of treatment for follicular lymphoma (FL) for two decades but is associated with immunosuppression and relapse. In phase 2 studies, lenalidomide combined with rituximab (R²) has shown clinical synergy in front‐line and relapsed/refractory FL. Here, we show that lenalidomide reactivated dysfunctional T and Natural Killer (NK) cells ex vivo from FL patients by enhancing proliferative capacity and T‐helper cell type 1 (Th1) cytokine release. In combination with rituximab, lenalidomide improved antibody‐dependent cellular cytotoxicity in sensitive and chemo‐resistant FL cells, via a cereblon‐dependent mechanism. While single‐agent lenalidomide and rituximab increased formation of lytic NK cell immunological synapses with primary FL tumour cells, the combination was superior and correlated with enhanced cytotoxicity. Immunophenotyping of FL patient samples from a phase 3 trial revealed that R² treatment increased circulating T‐ and NK‐cell counts, while R‐chemotherapy was associated with reduced cell numbers. Finally, using an in vitro model of myeloid differentiation, we demonstrated that lenalidomide caused a reversible arrest in neutrophil maturation that was distinct from a cytotoxic chemotherapeutic agent, which may help explain the lower rates of neutropenia observed with R²versus R‐chemotherapy. Taken together, we believe these data support a paradigm shift in the treatment of FL – moving from combination immunochemotherapy to chemotherapy‐free immunotherapy.

One Size Does Not Fit All: Who Benefits From Maintenance After Frontline Therapy for Follicular Lymphoma?

Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma and the most common indolent B-cell malignancy. The disease often presents in advanced stage and can often be observed before initiation of therapy. Although the incidence is only approximately 15,000 new cases per year, the prevalence is substantially higher owing to the favorable overall survival (OS) of most patients. The most impactful advance responsible for the improvement of OS in FL was the introduction of the anti-CD20 monoclonal antibody (mAb) rituximab over 20 years ago. Phase III trials demonstrate that rituximab improves the OS in FL when combined with chemotherapy. However, unlike aggressive B-cell lymphomas, advanced stage FL is generally incurable and often displays a pattern of progressively shorter remissions with subsequent lines of therapy. Hence, maintenance strategies have been developed to prolong remissions achieved with frontline therapy. The value of maintenance after frontline therapy has been most extensively studied with extended treatment of anti-CD20 mAb, but recent approaches include chemotherapy-free combinations and targeted therapies given for extended durations. Here, we review relevant data that provide rationale in support of maintenance therapy in FL as well as the risks and limitations of a "one-size-fits-all" approach. Importantly, we note the biologic and clinical heterogeneity across patients with FL that must be considered when making clinical decisions. Finally, we highlight ongoing research that explores response-adapted approaches based on the depth of response as defined by PET scans and assays for minimal residual disease (MRD) that aim to better personalize individual management strategies.

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.

Where to start? Upfront therapy for follicular lymphoma in 2018

The initial approach to the management of follicular lymphoma (FL) is challenging for patients and physicians. Most FL patients present with minimal symptoms; given the lack of a survival benefit to early treatment in this population, a period of observation without therapy is often appropriate. Once there is disease progression beyond low-tumor-burden criteria or symptoms prompting intervention, patients may be considered for an array of potential treatment options. These range from single-agent rituximab (anti-CD20) to various forms of chemoimmunotherapy, including rituximab or the newer anti-CD20 monoclonal antibody obinutuzumab. Unfortunately, prognostic and other clinical factors are of limited value in guiding optimal selection of therapy. Once patients complete initial treatment and achieve a complete or a partial remission, the next decision relates to the pros and cons of maintenance anti-CD20 therapy. Maintenance antibody administration can improve progression-free, but not overall, survival; hence, patient preferences typically drive this decision. Monitoring after remission is achieved should generally be guided by symptoms, physical examination, and laboratory findings, with routine surveillance imaging discouraged in the absence of new clinical issues. Given the wide range of options available and the importance of optimizing quality of life in this chronic health condition, education and shared decision making are pillars in the upfront management of FL to help patients achieve the best possible outcomes.

Rituximab plus Lenalidomide in Advanced Untreated Follicular Lymphoma

BACKGROUND

Rituximab plus chemotherapy has been shown to be effective in patients with advanced-stage, previously untreated follicular lymphoma; nevertheless, most patients will have a relapse. Combination immunotherapy with lenalidomide and rituximab is an immunomodulatory regimen that has shown promising activity in patients with indolent B-cell non-Hodgkin's lymphoma.

METHODS

We conducted this multicenter, international, phase 3 superiority trial to evaluate rituximab plus lenalidomide, as compared with rituximab plus chemotherapy, in patients with previously untreated follicular lymphoma. Patients were randomly assigned to receive one of the two regimens, followed by maintenance monotherapy with rituximab. Treatment with rituximab plus lenalidomide consisted of 18 cycles of the two drugs, followed by rituximab maintenance therapy every 8 weeks for 12 cycles (six additional doses). Treatment with rituximab plus chemotherapy consisted of the investigator's choice of one of three rituximab-based regimens, followed by maintenance monotherapy with rituximab every 8 weeks for 12 cycles. The primary end points were complete response (confirmed or unconfirmed) at 120 weeks and progression-free survival.

RESULTS

A total of 1030 patients were randomly assigned to receive rituximab plus lenalidomide (513 patients) or rituximab plus chemotherapy (517 patients). The rate of confirmed or unconfirmed complete response at 120 weeks was similar in the two groups: 48% (95% confidence interval [CI], 44 to 53) in the rituximab-lenalidomide group and 53% (95% CI, 49 to 57) in the rituximab-chemotherapy group (P=0.13). The interim 3-year rate of progression-free survival was 77% (95% CI, 72 to 80) and 78% (95% CI, 74 to 82), respectively. A higher percentage of patients in the rituximab-chemotherapy group had grade 3 or 4 neutropenia (32% vs. 50%) and febrile neutropenia of any grade (2% vs. 7%), and a higher percentage of patients in the rituximab-lenalidomide group had grade 3 or 4 cutaneous reactions (7% vs. 1%).

CONCLUSIONS

Among patients with previously untreated follicular lymphoma, efficacy results were similar with rituximab plus lenalidomide and rituximab plus chemotherapy (with both regimens followed by rituximab maintenance therapy). The safety profile differed in the two groups. (Funded by Celgene; RELEVANCE ClinicalTrials.gov numbers, NCT01476787 and NCT01650701 , and EudraCT number, 2011-002792-42 .).