Maintenance rituximab or observation after frontline treatment with bendamustine-rituximab for follicular lymphoma

The landscape of real-world evidence of rituximab utilization and clinical outcomes in patients with cancer, rheumatoid arthritis, and multiple sclerosis: A scoping review

BACKGROUND

Rituximab (RTX) is an anti-CD20 monoclonal antibody that is used to treat various conditions in cancer, rheumatoid arthritis (RA), and multiple sclerosis (MS). Although RTX has been used in the United States for almost 3 decades, questions remain regarding its real-world utilization and effectiveness.

OBJECTIVE

To describe the state of observational research and real-world evidence evaluating RTX in oncology, RA, and off-label use in MS.

METHODS

A broad search was conducted in MEDLINE, Embase, and CINAHL covering the period of January 2010 to June 2022. Two reviewers independently screened all identified records for each disease category (cancer, RA, MS) beginning with title review, followed by abstract, and full-text review to identify relevant publications to include in the final analysis. Data were extracted and summarized for each disease based on overall trends, similarities, and differences across included studies and stratified by disease state.

RESULTS

A total of 260 studies met eligibility criteria, with 79 studies for the RA cohort, 144 for cancer, and 37 for MS. Across all disease cohorts, most studies (n = 189; 72.7%) were retrospective. 171 (65.8%) studies used hospital or electronic health record data as their data source and 65 (23.2%) used registry databases. Most studies (n = 153; 58.8%) assessed the effectiveness of RTX measured by disease-specific endpoints, followed by safety (n = 60; 23.1%), treatment patterns (n = 32; 12.3%), and descriptive analyses assessing treatment adherence and economic burden of disease (n = 16; 6.2%). Although safety was not the primary outcome for most studies, the majority of studies across all disease states still reported some form of safety measure. Conclusive statements on RTX's benefit varied across disease states, with MS having the most (n = 30; 81.1%) studies suggesting the drug's positive benefit. There were limited studies assessing RTX use, associated economic burden, and biosimilar switching.

CONCLUSIONS

The findings underscore the need for health care providers to better understand the treatment landscape and utilization of RTX, particularly in terms of patient selection, timing of initiation, and long-term outcomes. Real-world evidence can help support health care decisions and treatment using rituximab.

Comparing R-Bendamustine vs. R-CHOP Plus Maintenance Therapy as First-Line Systemic Treatment in Follicular Lymphoma: A Multicenter Retrospective GELTAMO Study

Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and R-bendamustine (R-B) are the most common frontline treatment strategies for advanced-stage follicular lymphoma (FL). After R-CHOP induction therapy, using rituximab for maintenance therapy notably improves outcomes; however, whether this can be achieved by using the same approach after R-B therapy is still being determined. This retrospective analysis compared 476 FL patients from 17 GELTAMO centers who received R-based regimens followed by rituximab maintenance therapy for untreated advanced-stage FL. The complete response rate at the end of induction was higher with R-B and relapses were more frequent with R-CHOP. During induction, cytopenias were significantly more frequent with R-CHOP and so was the use of colony-stimulating factors. During maintenance therapy, R-B showed more neutropenia and infectious toxicity. After a median follow-up of 81 months (95% CI: 77-86), the 6-year rates of progression-free survival (PFS) were 79% (95% CI: 72-86) for R-bendamustine vs. 67% (95% CI: 61-73) for R-CHOP (p = 0.046), and 6-year overall survival (OS) values were 91% (95% CI: 86-96) for R-B vs. 91% (95% CI: 87-94) for R-CHOP (p = 0.49). In conclusion, R-B followed by rituximab maintenance therapy in patients with previously untreated FL resulted in significantly longer PFS than R-CHOP, with older patients also benefiting from this treatment without further toxicity. Adverse events during maintenance were more frequent with R-B without impacting mortality.

Impact of immunochemotherapy with R-bendamustine or R-CHOP for treatment naïve advanced-stage follicular lymphoma: A subset analysis of the FOLL12 trial by Fondazione Italiana Linfomi

We conducted a post hoc analysis of the FOLL12 trial to determine the impact of different initial immunochemotherapy (ICT) regimens on patient outcomes. Patients were selected from the FOLL12 trial, which included adults with stage II-IV follicular lymphoma (FL) grade 1-3a and high tumor burden. Patients were randomized 1:1 to receive either standard ICT followed by rituximab maintenance (RM) or the same ICT followed by a response-adapted approach. ICT consisted of rituximab-bendamustine (RB) or rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHOP), per physician's decision. A total of 786 patients were included in this analysis, 341 of whom received RB and 445 R-CHOP. RB was more frequently prescribed to older subjects, females, patients without bulky disease, and those with grade 1-2 FL. After a median of 56 months of follow-up, R-CHOP and RB had similar progression-free survival (PFS) (Hazard Ratio for RB 1.11, 95% CI 0.87-1.42, p = 0.392). Standard RM was associated with improved PFS compared to response-adapted management both after R-CHOP and RB. Grade 3-4 hematologic adverse events were more frequent with R-CHOP during induction treatment and more frequent with RB during RM. Grade 3-4 infections were more frequent with RB. RB was also associated with a higher incidence of transformed FL. R-CHOP and RB showed similar activity and efficacy, but with different safety profiles and long-term events, suggesting that the treating physician should carefully select the most appropriate chemotherapy regimen for each patient based on patient's individual characteristics, choices, and risk profile.

Personalised therapy in follicular lymphoma - is the dial turning?

Follicular lymphoma is the most common indolent lymphoma accounting for approximately 20%-25% of all new non-Hodgkin lymphoma diagnoses in western countries. Whilst outcomes are mostly favorable, the spectrum of clinical phenotypes includes high-risk groups with significantly inferior outcomes. This review discusses recent updates in risk stratification and treatment approaches from upfront treatment for limited and advanced stage follicular lymphoma to the growing options for relapsed, refractory disease with perspectives on how to approach this from a personalized lens. Notable gaps remain on how one can precisely and prospectively select optimal treatment for patients based on varying risks, with an anticipation that an increased understanding of the biology of these different phenotypes and increasing refinement of imaging- and biomarker-based tools will, in time, allow these gaps to be closed.

Ki67 proliferation index in follicular lymphoma is associated with favorable outcome in patients treated with R-CHOP

Follicular lymphoma (FL) is a common, indolent small B-cell lymphoma. While the Follicular Lymphoma International Prognostic Index is widely used, reliable prognostic and predictive biomarkers are needed. A recent study suggested that architectural patterns of CD10, BCL6, and Ki67 expression may correlate with progression-free survival (PFS) in FL patients treated with chemotherapy-free regimens. We examined the prognostic and predictive utility of architectural patterns of CD10, BCL6, Ki67, and FOXP1 in 90 patients treated with immunochemotherapy (bendamustine-rituximab [BR] and R-cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP]). We found that high follicular Ki67 (≥30%) was associated with longer PFS in the subgroup of patients treated with R-CHOP but not among those treated with BR. Validation of this biomarker may support routine use of Ki67 as a predictive marker in FL.

Impact of early relapse within 24 months after first-line systemic therapy (POD24) on outcomes in patients with marginal zone lymphoma: A US multisite study

Progression of disease within 24 months (POD24) from diagnosis in marginal zone lymphoma (MZL) was shown to portend poor outcomes in prior studies. However, many patients with MZL do not require immediate therapy, and the time from diagnosis-to-treatment interval can be highly variable with no universal criteria to initiate systemic therapy. Hence, we sought to evaluate the prognostic relevance of early relapse or progression within 24 months from systemic therapy initiation in a large US cohort. The primary objective was to evaluate the overall survival (OS) in the two groups. The secondary objective included the evaluation of factors predictive of POD24 and the assessment of cumulative incidence of histologic transformation (HT) in POD24 versus non-POD24 groups. The study included 524 patients with 143 (27%) in POD24 and 381 (73%) in non-POD24 groups. Patients with POD24 had inferior OS compared to those without POD24, regardless of the type of systemic therapy received (rituximab monotherapy or immunochemotherapy) at diagnosis. After adjusting for factors associated with inferior OS in the univariate Cox model, POD24 remained associated with significantly inferior OS (HR = 2.50, 95% CI = 1.53-4.09, p = 0.0003) in multivariable analysis. The presence of monoclonal protein at diagnosis and those who received first-line rituximab monotherapy had higher odds of POD24 on logistic regression analysis. Patients with POD24 had a significantly higher risk for HT compared to those without POD24. POD24 in MZL might be associated with adverse biology and could be used as an additional information point in clinical trials and investigated as a marker for worse prognosis.

Follicular lymphoma: an update on biology and optimal therapy

Follicular lymphoma (FL) is a mature B-cell neoplasm with a mostly indolent course. Genetic hallmark characteristics are Bcl-2 overexpression based on a t(14;18) translocation and additional secondary genetic and epigenetic aberrations. Standard treatment for early-stage patients has curative intent and usually consists of radiotherapy with or without rituximab. In the advanced stage, the main therapeutic focus is on prolonged remissions. Therefore, treatment in asymptomatic patients is usually deferred. Symptomatic patients are subject to immunochemotherapy induction followed by antibody maintenance. Importantly, about one in five patients subsequently experiences a more rapid clinical course, achieving only short remissions with multiple relapses (POD24). In those patients, there is still an urgent need for improved therapeutic options. Accordingly, a plethora of targeted and immunotherapeutic options, including immunomodulatory drugs, small molecule inhibitors, monoclonal antibodies as well as bispecific T-cell engager antibodies and CAR-T cell products have been recently evaluated in such relapsed high-risk patients.

Benefit of rituximab maintenance is associated with Follicular Lymphoma International Prognostic Index in patients with follicular lymphoma

Rituximab maintenance (RM) prolongs the progression-free survival (PFS) of responding patients with follicular lymphoma (FL), but the maintenance efficacy in different Follicular Lymphoma International Prognostic Index (FLIPI) risk group is still confusing. We performed a retrospective analysis of the effect of RM treatments in patients with FL responding to induction therapy based on their FLIPI risk assessment carried out prior to treatment. We identified 93 patients between 2013 and 2019 who received RM every 3 months for ≥4 doses (RM group), and 60 patients who did not accept RM or received rituximab less than 4 doses (control group). After a median follow-up of 39 months, neither median overall survival (OS) nor PFS was reached for the entire population. The PFS was significantly prolonged in the RM group compared to the control group (median PFS NA vs 83.1 months, P = .00027). When the population was divided into the 3 FLIPI risk groups, the PFS differed significantly (4-year PFS rates, 97.5% vs 88.8% vs 72.3%, P = .01) according to group. There was no significant difference in PFS for FLIPI low-risk patients with RM compared to the control group (4-year PFS rates, 100% vs 93.8%, P = .23). However, the PFS of the RM group was significantly prolonged for FLIPI intermediate-risk (4-year PFS rates, 100% vs 70.3%, P = .00077) and high-risk patients (4-year PFS rates, 86.7% vs 57.1%, P = .023). These data suggest that standard RM significantly prolongs the PFS of patients assigned to intermediate- and high-risk FLIPI groups but not to low-risk FLIPI group, and pending larger-scale studies to validate.

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.

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.

An international analysis evaluating frontline bendamustine with rituximab in extranodal marginal zone lymphoma

Extranodal marginal zone lymphoma (EMZL) is a heterogeneous non-Hodgkin lymphoma. No consensus exists regarding the standard-of-care in patients with advanced-stage disease. Current recommendations are largely adapted from follicular lymphoma, for which bendamustine with rituximab (BR) is an established approach. We analyzed the safety and efficacy of frontline BR in EMZL using a large international consortium. We included 237 patients with a median age of 63 years (range, 21-85). Most patients presented with Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 (n = 228; 96.2%), stage III/IV (n = 179; 75.5%), and intermediate (49.8%) or high (33.3%) Mucosa Associated Lymphoid Tissue International Prognosis Index (MALT-IPI). Patients received a median of 6 (range, 1-8) cycles of BR, and 20.3% (n = 48) received rituximab maintenance. Thirteen percent experienced infectious complications during BR therapy; herpes zoster (4%) was the most common. Overall response rate was 93.2% with 81% complete responses. Estimated 5-year progression-free survival (PFS) and overall survival (OS) were 80.5% (95% CI, 73.1% to 86%) and 89.6% (95% CI, 83.1% to 93.6%), respectively. MALT-IPI failed to predict outcomes. In the multivariable model, the presence of B symptoms was associated with shorter PFS. Rituximab maintenance was associated with longer PFS (hazard ratio = 0.16; 95% CI, 0.04-0.71; P = .016) but did not impact OS. BR is a highly effective upfront regimen in EMZL, providing durable remissions and overcoming known adverse prognosis factors. This regimen is associated with occurrence of herpes zoster; thus, prophylactic treatment may be considered.

Efficacy of front-line immunochemotherapy for follicular lymphoma: a network meta-analysis of randomized controlled trials

Front-line treatment for follicular lymphoma has evolved with the introduction of maintenance therapy, bendamustine (Benda), obinutuzumab (G), and lenalidomide (Len). We conducted a random-effects Bayesian network meta-analysis (NMA) of phase 3 randomized controlled trials (RCTs) to identify the regimens with superior efficacy. Progression-free survival (PFS) was compared between 11 modern regimens with different immunochemotherapy and maintenance strategies. G-Benda-G resulted in with the best PFS, with an HR of 0.41 compared to R-Benda, a surface under the cumulative ranking curve (SUCRA) of 0.97, a probability of being the best treatment (PbBT) of 72%, and a posterior ranking distribution (PoRa) of 1 (95% BCI 1-3). This was followed by R-Benda-R4 (HR = 0.49, PbBT = 25%, PoRa = 2) and R-Benda-R (HR = 0.60, PbBT = 3%, PoRa = 3). R-CHOP-R (HR = 0.96) and R-Len-R (HR = 0.97) had similar efficacy to R-Benda. Bendamustine was a better chemotherapy backbone than CHOP either with maintenance (R-Benda-R vs R-CHOP-R, HR = 0.62; G-Benda-G vs G-CHOP-G, HR = 0.55) or without maintenance therapy (R-Benda vs R-CHOP, HR = 0.68). Rituximab maintenance improved PFS following R-CHOP (R-CHOP-R vs R-CHOP, HR = 0.65) or R-Benda (R-Benda-R vs R-Benda, HR = 0.60; R-Benda-R4 vs R-Benda, HR = 0.49). In the absence of multi-arm RCTs that include all common regimens, this NMA provides an important and useful guide to inform treatment decisions.

Late-onset complications with bendamustine versus CHOP or CVP based chemoimmunotherapy in indolent Non-Hodgkin's lymphoma

Bendamustine is a preferred first-line chemoimmunotherapy regimen for indolent non-Hodgkin's lymphoma (iNHL). Emerging evidence suggests an increased incidence of late-onset complications with bendamustine-based regimens compared with CHOP/CVP; however, this evidence is limited. We retrospectively compared late-onset complications from January 2005 to May 2020 in adults with previously untreated iNHL who received rituximab or obinutuzumab with CHOP, CVP, or bendamustine. Forty-six patients received CHOP/CVP; 119 received bendamustine. No difference in incidence of late-onset infections was observed. Bendamustine led to a higher rate of prolonged and unresolved lymphocytopenia and a greater incidence of late-onset neutropenia. Many patients receiving bendamustine did not have lymphocyte recovery even three years following administration. Ongoing infection prophylaxis with bendamustine-based regimens may offset translation of these laboratory findings to late-onset infectious risk.

Reduction of cycles of bendamustine plus rituximab therapy in the cases with good response for indolent B-cell lymphomas

Bendamusutine plus rituximab (BR) regimen is one of the standard regimens for indolent B-cell lymphomas, yet the possibility of reduction of cycles of BR therapy without compromising therapeutic effects is not still uncovered. We retrospectively surveyed 57 cases including 40 follicular lymphoma cases who underwent BR regimen in our institute. The overall response (OR) rate and complete response (CR) rate were 86.0% (95% confidential interval (CI), 74.2-93.7) and 54.4% (40.7-67.6), respectively. Five-year overall survival (OS) and 5-years progression-free survival (PFS) were 76.8% and 45.7%, respectively. We then grouped the patients by the number of administered cycles of BR regimen. PFS was significantly longer in 41 cases of the later cessation group (cycle 4-6) than in 16 cases of the earlier cessation group (cycle 1-3) (p = 0.012, 5-years PFS; 46.8% vs. 35.2%, respectively), and both of OR and CR rate of the former was better than the latter (OR rate; 95.1% vs. 62.5%, p < 0.01, CR rate; 61.4% vs. 31.3%, p = 0.04). Interestingly PFS of twenty-one (36.8%) cases receiving just 4 cycles was longer than that of 20 cases who received five or 6 cycles (p < 0.01, 5-years PFS; 71.8% vs. 23.2%, respectively). Focusing on the group of four cycles, the 12 case with CR revealed longer PFS than seven cases with partial response (PR), and median PFS was not reached in CR cases and 16.9 months in the PR cases (p < 0.01). These results suggest that four cycles at least should be administered if possible, and the outcome of the patients who discontinued BR after four cycles was not inferior to that of the cases who received five or six cycles. In conclusion, discontinuation after four cycles may be permissible in some cases with complete response to BR regimen.

Novel Therapy Approaches to Follicular Lymphoma

Follicular lymphoma (FL) is the most common form of indolent non-Hodgkin lymphoma. It is a disease characterised by a long median overall survival and high response rates to currently available chemotherapy and anti-CD20 monoclonal antibody therapy combinations. However, for a sub-group of patients the disease behaves aggressively, fails to respond adequately to initial therapy or relapses early. For others, the disease becomes resistant following multiple lines of therapy, and despite recent advances the main cause of death for patients with FL remains their lymphoma. A wide landscape of novel therapies is emerging and the role of individual agents in the FL treatment paradigm is still being established. Some agents, including the cereblon modulator lenalidomide, the phosphatidylinositol 3-kinase inhibitors idelalisib, copanlisib and duvelisib, and the EZH2 inhibitor tazemetostat have received regulatory approval in the USA or European Union and have entered clinical practice for relapsed FL. Other developments, such as the emergence of immunotherapies including CAR-T cell therapy and bispecific antibodies, are expected to fundamentally change the approach to FL treatment in the future.

How we treat mature B-cell neoplasms (indolent B-cell lymphomas)

Mature B cell neoplasms, previously indolent non-Hodgkin lymphomas (iNHLs), are a heterogeneous group of malignancies sharing similar disease courses and treatment paradigms. Most patients with iNHL have an excellent prognosis, and in many, treatment can be deferred for years. However, some patients will have an accelerated course and may experience transformation into aggressive lymphomas. In this review, we focus on management concepts shared across iNHLs, as well as histology-specific strategies. We address open questions in the field, including the influence of genomics and molecular pathway alterations on treatment decisions. In addition, we review the management of uncommon clinical entities including nodular lymphocyte-predominant Hodgkin lymphoma, hairy cell leukemia, splenic lymphoma and primary lymphoma of extranodal sites. Finally, we include a perspective on novel targeted therapies, antibodies, antibody-drug conjugates, bispecific T cell engagers and chimeric antigen receptor T cell therapy.

Precision medicine in follicular lymphoma: Focus on predictive biomarkers

Current care for patients with follicular lymphoma (FL) offers most of them long-term survival. Improving it further will require careful patient selection. This review focuses on predictive biomarkers (ie, those whose outcome correlations depend on the treatment strategy) in FL, because awareness of what patient subsets benefit most or least from each therapy will help in this task. The first part of this review aims to summarize what biomarkers are predictive in FL, the magnitude of the effect and the quality of the evidence. We find predictive biomarkers in the setting of (a) indication of active treatment, (b) front-line induction (use of anthracyline-based regimens, CHOP vs bendamustine, addition of rituximab), (c) post-(front-line)induction (rituximab maintenance, radioimmunotherapy), and (d) relapse (hematopoietic stem cell transplant) and targeted agents. The second part of this review discusses the challenges of precision medicine in FL, including (a) cost, (b) clinical relevance considerations, and (c) difficulties over the broad implementation of biomarkers. We then provide our view on what biomarkers may become used in the next few years. We conclude by underscoring the importance of assessing the potential predictiveness of available biomarkers to improve patient care but also that there is a long road ahead before reaching their broad implementation due to remaining scientific, technological, and economic hurdles.

Antibody Therapy Maintenance in Follicular Lymphoma

Because patients with follicular lymphoma (FL) usually experience repeated disease recurrences, maintenance treatment is an attractive option to prolong remission after induction therapy. Rituximab maintenance therapy has been shown in multiple randomized studies to significantly improve progression-free survival in FL with both low and high tumor burden after induction therapy, independently of patient and disease characteristics. Several questions regarding the use of antibody directed against CD20 (anti-CD20) maintenance remain open, including the optimal antibody administration schedule and duration, the risk/benefit ratio of maintenance in the context of previous bendamustine administration, and its cost-effectiveness.

Pretreatment SUVmax may influence the clinical benefit of BR over R-CHOP in patients with previously untreated FL

In 2 randomized phase 3 trials BR resulted in longer progression-free survival (PFS) than frontline R-CHOP in patients with indolent and mantle cell lymphoma. However, in subset analyses of follicular lymphoma (FL), the results were incongruent. We conducted a retrospective matched-pair analysis to compare the outcome of patients with advanced stage FL, receiving frontline BR (N = 73) or R-CHOP (N = 73), matched by age, gender, stage, and FL International Prognostic Index score. On multivariable analysis, baseline maximum standardized uptake value (SUV_max) >13 was associated with use of R-CHOP (p = .001). After a median follow-up of 69 months for the BR arm and 126 months for the R-CHOP arm, 5-year PFS was 80% and 70%, respectively (p = .07). After adjusting for SUV_max >13, the trend for better PFS in BR was not maintained. Prospective studies are needed to validate the role of pretreatment SUV_max as a stratification factor in future randomized therapeutic trials in FL.

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

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.

Radiotherapy of extranodal low-grade follicular and marginal zone lymphomas: long-term follow-up of 159 patients

OBJECTIVE

To evaluate clinical, histopathologic, and radiation (RT) dose parameters in patients with extranodal low-grade (ENLG) non-Hodgkin lymphoma (NHL) and their possible impact on local control (LC) and survival.

MATERIALS AND METHODS

The medical records of 159 patients with 181 histologically confirmed ENLG-NHL lesions treated at our institution were reviewed retrospectively.

RESULTS

The predominant histological subtype (73%) was marginal zone lymphoma (MZL). Common lesion sites were the gastrointestinal tract (GIT; 33%), skin (26%), and orbit (21%). The majority of patients (88%) presented with stage I/II disease. Thirty-three (20%) lesions were treated with reduced-dose RT (≤30.6 Gy) and 148 lesions (80%) with conventional-dose RT (>30.6 Gy), with an overall median dose of 39.6 Gy (range 4-63). The median follow-up period was 72 months. The 10-year local control (LC), Progression-free survival (PFS), and overall survival (OS) rates were 96, 65, and 82%, respectively. Higher overall response rate (ORR; 98% vs. 94%, p = 0.001) and complete response rate (CRR; 95% vs. 73%, p = 0.001) were observed in patients treated with conventional-dose regimens than in those treated with reduced-dose regimens. Ten-year PFS (p = 0.90) and OS (p = 0.40) was similar between the two dose groups. RT was well tolerated in both dose groups, with no grade 4/5 toxicities. In the multivariate analysis, RT dose and timing (upfront or salvage) were related to LC, whereas age, histology, and complete response (CR) to RT were associated with PFS. Patient age and radiation field size impacted OS.

CONCLUSION

RT is an effective and curative local treatment for early-stage FL and MZL at conventional and reduced radiation doses. Conventional-doses seems to be associated with local response improvement, without significant differences in PFS rates. Age, histology, and response to RT may influence the PFS.

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.