Follicular lymphoma: time for a re-think?

Metronomic chemotherapy in hematology: Lessons from preclinical and clinical studies to build a solid rationale for future schedules

Metronomic chemotherapy (mCHEMO), based on frequent, regular administration of low, but pharmacologically active drug doses, optimizes antitumor efficacy by targeting multiple targets and reducing toxicity of antineoplastic drugs. This minireview will summarize preclinical and clinical studies on cytotoxic drugs given at weekly, daily, or at continuous metronomic schedules alone or in combination with novel targeted agents for hematological malignancies, including lymphoma, multiple myeloma, and leukemia. Most of the preclinical in vitro and in vivo studies have reported a significant benefit of both mCHEMO monotherapy and combinatorial regimens compared with chemotherapy at the maximum tolerated dose. However, the combination of mCHEMO with targeted drugs is still little explored in the hematologic clinical setting. Data obtained from preclinical studies on low dose metronomic chemotherapy in hematological malignancies clearly suggested the possibility to clinically investigate more tolerable and effective strategies for the treatment of patients with advanced hematological malignancies, or at least for those frail and elderly patients, who are not eligible or resistant to standard treatments.

An analysis of genetic targets for guiding clinical management of follicular lymphoma

Introduction: Follicular lymphoma (FL) is one of the most common non-Hodgkin lymphoma (NHL) types, where genomic studies have accumulated potentially useful information about frequently mutated genes and deregulated pathways, which has allowed to a better understanding of the molecular pathogenesis of this tumor and the complex interrelationship between the tumoral cells and the stroma. Areas covered: The results of the molecular studies performed on Follicular Lymphoma have been here reviewed, summarizing the results of the clinical trials so far developed on this basis and discussing the reasons for the successes and failures. Searches were performed on June 1^st, 2020, in PubMed and ClinicalTrials.gov. Expert opinion: Targeted therapy for follicular lymphoma has multiple opportunities including the use of epigenetic drugs, PI3K inhibitors, modifiers of the immune stroma and others. Data currently known on FL pathogenesis suggest that combining these treatments with immunotherapy should be explored in clinical trials, mainly for patients with clinical progression or adverse prognostic markers. Association of targeted trials with dynamic molecular studies of the tumor and serum samples is advised. Chemotherapy-free approaches should also be explored as first-line therapy for FL patients.

Progression of Disease Within 24 Months in Follicular Lymphoma Is Associated With Reduced Intratumoral Immune Infiltration

PURPOSE

Understanding the immunobiology of the 15% to 30% of patients with follicular lymphoma (FL) who experience progression of disease within 24 months (POD24) remains a priority. Solid tumors with low levels of intratumoral immune infiltration have inferior outcomes. It is unknown whether a similar relationship exists between POD24 in FL.

PATIENTS AND METHODS

Digital gene expression using a custom code set—five immune effector, six immune checkpoint, one macrophage molecules—was applied to a discovery cohort of patients with early- and advanced-stage FL (n = 132). T-cell receptor repertoire analysis, flow cytometry, multispectral immunofluorescence, and next-generation sequencing were performed. The immune infiltration profile was validated in two independent cohorts of patients with advanced-stage FL requiring systemic treatment (n = 138, rituximab plus cyclophosphamide, vincristine, prednisone; n = 45, rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone), with the latter selected to permit comparison of patients experiencing a POD24 event with those having no progression at 5 years or more.

RESULTS

Immune molecules showed distinct clustering, characterized by either high or low expression regardless of categorization as an immune effector, immune checkpoint, or macrophage molecule. Low programmed death-ligand 2 (PD-L2) was the most sensitive/specific marker to segregate patients with adverse outcomes; therefore, PD-L2 expression was chosen to distinguish immune infiltration^HI (ie, high PD-L2) FL biopsies from immune infiltration^LO (ie, low PD-L2) tumors. Immune infiltration^HI tissues were highly infiltrated with macrophages and expanded populations of T-cell clones. Of note, the immune infiltration^LO subset of patients with FL was enriched for POD24 events (odds ratio [OR], 4.32; c-statistic, 0.81; P = .001), validated in the independent cohorts (rituximab plus cyclophosphamide, vincristine, prednisone: OR, 2.95; c-statistic, 0.75; P = .011; and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone: OR, 7.09; c-statistic, 0.88; P = .011). Mutations were equally proportioned across tissues, which indicated that degree of immune infiltration is capturing aspects of FL biology distinct from its mutational profile.

CONCLUSION

Assessment of immune-infiltration by PD-L2 expression is a promising tool with which to help identify patients who are at risk for POD24.

Randomized Trial of Systemic Therapy After Involved-Field Radiotherapy in Patients With Early-Stage Follicular Lymphoma: TROG 99.03

Purpose

Follicular lymphoma (FL) is curable by involved-field radiotherapy (IFRT) in < 50% of patients with stage I to II disease. We hypothesized that adding systemic therapy to IFRT would improve long-term progression-free survival (PFS).

Patients and Methods

A multicenter randomized controlled trial enrolled patients with stage I to II low-grade FL after staging computed tomography scans and bone marrow biopsies. 18F-labeled fluorodeoxyglucose–positron emission tomography (PET) was not mandatory. Patients were randomly assigned to either arm A (30 Gy IFRT alone) or arm B (IFRT plus six cycles of cyclophosphamide, vincristine, and prednisolone [CVP]). From 2006, rituximab was added to arm B (R-CVP).

Results

Between 2000 and 2012, 150 patients were enrolled, 75 per arm. In arm B, 44 patients were allocated to receive CVP and 31 were allocated to receive R-CVP. At randomization, 75% had stage I, the median age was 57 years, 52% were male, and 48% were PET staged. With a median follow-up of 9.6 years (range, 3.1 to 15.8 years), PFS was superior in arm B (hazard ratio, 0.57; 95% CI, 0.34 to 0.95; P = .033). Ten-year PFS rates were 59% (95% CI, 46% to 74%) and 41% (95% CI, 30% to 57%) for arms B and A, respectively. Patients in arm B who received R-CVP had markedly superior PFS compared with contemporaneous patients in arm A (hazard ratio, 0.26; 95% CI, 0.07 to 0.97; P = .045). Fewer involved regions ( P = .047) and PET staging ( P = .056) were associated with better PFS. Histologic transformation occurred in four and 10 patients in arms B and A, respectively ( P = .1). Ten deaths occurred in arm A versus five in arm B, but overall survival was not significantly different ( P = .40; 87% and 95% at 10 years, respectively).

Conclusion

Systemic therapy with R-CVP after IFRT reduced relapse outside radiation fields and significantly improved PFS. IFRT followed by immunochemotherapy is more effective than IFRT in early-stage FL.

A new frontier in haematology - combining pharmacokinetic with pharmacodynamic factors to improve choice and dose of drug

The issue of tailored dosing adjusted according to a range of patient-specific factors other than bodyweight or body surface area is of large and increasing clinical and financial concern. Even if it is known that dosing alterations are likely to be required for parameters such as body composition, gender and pharmacogenetics, the amount of dosing change is unknown. Thus, pharmacokinetically guided dosing is making a resurgence, particularly in areas of medicine where there are cost constraints or safety issues, such as in haematology medications. However, the evidence to support the behaviour is minimal, particularly when long-term outcomes are considered. In haematology, there are particular issues around efficacy, toxicity and overall cost. Newer targeted agents, such as the monoclonal antibody rituximab and the tyrosine kinase inhibitor imatinib, whilst clearly being highly effective, are dosed on a milligram per square metre (rituximab) or fixed dose basis (imatinib), regardless of body composition, tumour aspects or comorbidity. This review questions this practice and raises important clinical issues; specifically, the clinical potential for combined pharmacokinetically and pharmacodynamically guided dosing of new targeted agents in haematological malignancies. This pharmacokinetically and pharmacodynamically guided dosing is an emerging area of clinical pharmacology, driven predominantly by toxicity, efficacy and cost issues, but also because reasonable outcomes are being noted with more appropriately dosed older medications adjusted for patient-specific factors. Clinical trials to investigate the optimization of rituximab dose scheduling are required.

Combining low-dose or metronomic chemotherapy with anticancer vaccines: A therapeutic opportunity for lymphomas

Therapeutic vaccination is regarded as a promising strategy against multiple hematological malignancies including lymphoma. However, this approach alone possesses limited potential for the treatment of established tumors. As several anticancer regimens relies on the combination of multiple drugs, it is reasonable to predict that also cancer vaccination will be most effective in the context of multimodal approaches. In particular, low-dose or metronomic chemotherapy could be coupled to anticancer vaccines to improve the efficacy of this immunotherapeutic interventions. This review summarizes recent findings in support of the use of anticancer vaccines combined with low-dose or metronomic chemotherapy for the treatment and management of lymphoid malignancies.

Early stage follicular lymphoma: what is the clinical impact of the first-line treatment strategy?

BACKGROUND

Less than 20% of patients with follicular lymphoma (FL) present with Ann Arbor Stage I or II disease at diagnosis. Numerous therapeutic options exist, however radiation therapy is considered the standard of care for early-stage disease based on single-institution or retrospective series. Our aim was to revisit the outcome of patients with localized FL in the rituximab era.

PATIENTS AND METHODS

We analyzed the characteristics and outcomes of 145 early-stage FL patients, who were retrospectively divided into six groups according to their initial treatment: watchful waiting (WW), chemotherapy alone (CT), radiotherapy alone (RT), combined radiotherapy and chemotherapy (RT-CT), rituximab alone (Ri), and immunochemotherapy (Ri-CT).

RESULTS

Of the 145 patients, 84 (57.9%) had stage I disease and 61 (42.1%) stage II. The complete response (CR) rate varied from 57% for the Ri group to 95% for the RT-CT group. Overall survival (OS) at 7.5 y of patients treated after 2000 was better than that of those treated prior to 2000. OS did not significantly differ from one treatment to another. In contrast, a significant difference was found for progression-free survival (PFS) at 7.5 y, which favored Ri-CT (60%) therapy versus the others (p=0.00135).

CONCLUSION

Delayed therapy initiation was associated with a similar OS than that observed in patients receiving immediate intervention. The "watchful waiting" strategy may thus be proposed as first-line therapy, similar to stage III and IV FL patients with a low tumor burden. However, when treatment is required, immunochemotherapy appears to be the best option.

Management of indolent lymphoma: where are we now and where are we going

Indolent lymphoma comprises a unique and challenging subset of non-Hodgkin lymphoma (NHL). While definitions of indolence will vary, the most common indolent NHL subtypes include follicular lymphoma, marginal zone lymphoma, and small lymphocytic lymphoma. Patients with indolent NHL (iNHL) excluding those with rare localized presentations are often met with an incurable but highly treatable NHL. In the rituximab era, response rates are approaching 90% with rituximab plus chemotherapy and time to next treatment are beginning to be measured in years. As a result of a prolonged natural history, we are encountering a gridlock of novel regimens and agents that appropriately fill peer-reviewed journals. In this review, we tackle a spectrum of topics in the management of indolent lymphoma including the initial approach to the newly diagnosed patient, approaches to first cytotoxic chemotherapy, maintenance and consolidation techniques, as well as highlight promising treatments on the horizon in iNHL. Clinicians continue to face tough choices in the management of iNHL. Through well-thought out clinical trials and peer-reviewed vetting of data we will continue to determine how to best manage the clinical continuum that is iNHL.

Initial management strategies for follicular lymphoma

Follicular lymphoma (FL) can vary markedly in its initial presentation, and no single standard approach for its initial management has been adopted. Available options for the initial management of FL include watchful waiting, radiation, single-agent rituximab and combination of rituximab and chemotherapy with strategies segregated for patients who have low and high tumor burden disease based on established criteria. However, marked debate occurs regarding the role of watchful waiting in the modern era for low tumor burden, asymptomatic patients, the optimal timing of rituximab, the selection of chemotherapy regimen to partner with rituximab in high tumor burden patients, and strategies for the management of relapsed disease. We provide an evidence-based discussion on these and other issues regarding the management of FL, and propose a mathematical modeling approach for addressing some of these questions.

Bortezomib plus rituximab versus rituximab alone in patients with relapsed, rituximab-naive or rituximab-sensitive, follicular lymphoma: a randomised phase 3 trial

BACKGROUND

Bortezomib and rituximab have shown additive activity in preclinical models of lymphoma, and have been shown to be active and generally well tolerated in a randomised phase 2 study in patients with follicular and marginal zone lymphoma. We compared the efficacy and safety of rituximab alone or combined with bortezomib in patients with relapsed or refractory follicular lymphoma in a phase 3 setting.

METHODS

In this multicentre phase 3 trial, rituximab-naive or rituximab-sensitive patients aged 18 years or older with relapsed grade 1 or 2 follicular lymphoma were randomly assigned (1:1) to receive five 35-day cycles consisting of intravenous infusions of rituximab 375 mg/m(2) on days 1, 8, 15, and 22 of cycle 1, and on day 1 of cycles 2-5, either alone or with bortezomib 1·6 mg/m(2), administered by intravenous injection on days 1, 8, 15, and 22 of all cycles. Randomisation was stratified by FLIPI score, previous use of rituximab, time since last therapy, and region. Treatment assignment was based on a computer-generated randomisation schedule prepared by the sponsor. Patients and treating physicians were not masked to treatment allocation. The primary endpoint was progression-free survival analysed by intention to treat. This trial has been completed and is registered with ClinicalTrials.gov, number NCT00312845.

FINDINGS

Between April 10, 2006, and Aug 12, 2008, 676 patients were randomised to receive rituximab (n=340) or bortezomib plus rituximab (n=336). After a median follow-up of 33·9 months (IQR 26·4-39·7), median progression-free survival was 11·0 months (95% CI 9·1-12·0) in the rituximab group and 12·8 months (11·5-15·0) in the bortezomib plus rituximab group (hazard ratio 0·82, 95% CI 0·68-0·99; p=0·039). The magnitude of clinical benefit was not as large as the anticipated prespecified improvement of 33% in progression-free survival. Patients in both groups received a median of five treatment cycles (range 1-5); 245 of 339 (72%) and 237 of 334 (71%) patients in the rituximab and bortezomib plus rituximab groups, respectively, completed five cycles. Of patients who did not complete five cycles, most discontinued early because of disease progression (77 [23%] patients in the rituximab group, and 56 [17%] patients in the bortezomib plus rituximab group). Rates of adverse events of grade 3 or higher (70 [21%] of 339 rituximab-treated patients vs 152 [46%] of 334 bortezomib plus rituximab treated patients), and serious adverse events (37 [11%] patients vs 59 [18%] patients) were lower in the rituximab group than in the combination group. The most common adverse events of grade 3 or higher were neutropenia (15 [4%] patients in the rituximab group and 37 [11%] patients in the bortezomib plus rituximab group), infection (15 [4%] patients and 36 [11%] patients, respectively), diarrhoea (no patients and 25 [7%] patients, respectively), herpes zoster (one [<1%] patient and 12 [4%] patients, respectively), nausea or vomiting (two [<1%] patients and 10 [3%] patients, respectively) and thrombocytopenia (two [<1%] patients and 10 [3%] patients, respectively). No individual serious adverse event was reported by more than three patients in the rituximab group; in the bortezomib plus rituximab group, only pneumonia (seven patients [2%]) and pyrexia (six patients [2%]) were reported in more than five patients. In the bortezomib plus rituximab group 57 (17%) of 334 patients had peripheral neuropathy (including sensory, motor, and sensorimotor neuropathy), including nine (3%) with grade 3 or higher, compared with three (1%) of 339 patients in the rituximab group (no events of grade ≥3). No patients in the rituximab group but three (1%) patients in the bortezomib plus rituximab group died of adverse events considered at least possibly related to treatment.

INTERPRETATION

Although a regimen of bortezomib plus rituximab is feasible, the improvement in progression-free survival provided by this regimen versus rituximab alone was not as great as expected. The regimen might represent a useful addition to the armamentarium, particularly for some subgroups of patients.

FUNDING

Johnson & Johnson Pharmaceutical Research & Development and Millennium Pharmaceuticals, Inc.

Host genetics in follicular lymphoma

The role of inherited (host) genetic susceptibility in the pathogenesis of follicular lymphoma (FL) is reviewed. First degree relatives of FL patients are at an increased risk of FL, suggesting a role for inherited factors. While there have been no linkage studies in FL families, candidate gene and genome-wide association studies have identified several risk loci which have been confirmed in independent studies. These include regions on 6p21.32-33 and TNF family members. Host genetics has also been hypothesized to influence treatment response, disease progression and overall survival. Early leads in FL prognosis include pathways that regulate immune function, antibody-dependent cellular cytotoxicity, chemotaxis, and one-carbon metabolism, although few of these associations have been independently confirmed. While the use of host genetics to identify individuals at high risk of FL or to predict FL treatment response and prognosis appears to be very promising, it is not yet ready for the clinic.

Vaccination strategies in follicular lymphoma

Follicular lymphoma is one of the most immune-responsive cancers. The clonal tumor immunoglobulin expressed on the surface of malignant B cells, termed idiotype, has been used as a tumor-specific antigen in therapeutic vaccination strategies for follicular lymphoma and other B-cell malignancies. A number of phase 1 and phase 2 clinical trials have established the safety and immunogenicity of idiotype vaccine in follicular lymphoma. Three randomized, double-blind, controlled phase 3 clinical trials have recently been completed to definitively evaluate the clinical benefit of idiotype vaccine in follicular lymphoma. This review focuses on the results of these idiotype vaccine trials and discusses potential strategies to enhance the efficacy of vaccines in the future.

Flavopiridol, fludarabine, and rituximab in mantle cell lymphoma and indolent B-cell lymphoproliferative disorders

PURPOSE

Flavopiridol downmodulates antiapoptotic proteins associated with resistance to fludarabine and rituximab and is effective against p53-mutated chronic lymphocytic leukemia (CLL). We conducted a phase I study of flavopiridol, fludarabine, and rituximab (FFR) in patients with mantle-cell lymphoma (MCL), indolent B-cell non-Hodgkin's lymphomas (B-NHL), and CLL to determine the activity of FFR.

PATIENTS AND METHODS

Therapy included fludarabine 25 mg/m(2) intravenously (IV) days 1 to 5 and rituximab 375 mg/m(2) day 1 every 28 days for 6 cycles. We administered flavopiridol 50 mg/m(2) by 1-hour IV bolus (IVB) day 1 (n = 15); day 1 to 2 (n = 6); 20 mg/m(2) 30-minute IVB + 20 mg/m(2) 4-hour IV infusion (n = 3); or 30 mg/m(2) + 30 mg/m(2) (n = 14).

RESULTS

Thirty-eight patients (median age, 62 years) with MCL (n = 10); indolent B-NHL including follicular (n = 9), marginal zone (n = 4), lymphoplasmacytic (n = 1), or small lymphocytic lymphoma (n = 3); and CLL (n = 11), were enrolled. Twenty-two patients were previously untreated; 16 had received one to two prior therapies. Two patients in cohort 2 developed grade 3 dose-limiting toxicity (seizures, renal insufficiency). The median number of treatment cycles was 4, with cytopenias (n = 10) and fatigue (n = 3) the most common reasons for early discontinuation. Overall response rate was 82% (complete response, 50%; unconfirmed complete response, 5%; partial response, 26%), including 80% of patients with MCL (median age, 68; seven complete responses, one partial response). Median progression-free survival (PFS) was 25.6 months. Median PFS of patients with nonblastoid variant MCL (n = 8) was 35.9 months.

CONCLUSION

FFR was active in MCL, indolent B-NHL, and CLL and should be studied for older patients with MCL who are not candidates for aggressive chemotherapy.

Developing curcumin into a viable therapeutic for lymphoma

BACKGROUND

Emerging evidence suggests that natural plant ingredients have played an important role in the healthcare of many countries. Several of these natural plant products possess therapeutic potential for various diseases including cancer. Curcumin is the pigment of turmeric, a well-known chemopreventive agent that has been shown to suppress the proliferation of a wide variety of tumor cells, including lymphoma. Curcumin has been shown to have cancer chemopreventive potential against a variety of tumors via targeting key survival pathways that are aberrantly activated in cancer cells.

METHODS

This review discusses therapeutic potential of curcumin in malignancies of lymphoma as well as therapeutic implications of the recent advances in the field.

RESULTS/CONCLUSION

Dietary-compound curcumin hardwires to multiple cellular processes. Suppression of cell proliferation, induction of apoptosis, and inhibition of metastasis are considered to be the major mechanisms underlying its anticancer properties.

Follicular lymphoma: a historical overview

Lymphoma was first described in 1862 and follicular lymphoma in 1925. Initially considered a benign disorder, and named Brill - Symmers disease after the authors of the original papers, it was rapidly recognized as a malignancy with a variable but often indolent course. Most of its clinical features were described by the early 1940s. Despite discussion about its cell of origin, and in contrast to many other lymphoma subtypes, follicular lymphoma could always be accurately recognized and diagnosed using light microscopy morphological features. B-cell origin was demonstrated in the 1970s and the important role of t(14;18) and bcl-2 gene rearrangement in the pathogenesis of follicular lymphoma was established shortly thereafter. The etiology of follicular lymphoma, the reason for marked geographic variation in its incidence, the role of alternative molecular pathways in its pathogenesis, and the cause for its variable clinical behavior all remain unknown. Several observations suggest an important role for the normal immune response in regulating the clinical behavior of follicular lymphoma. From the earliest descriptions, radiation therapy was shown to be very effective in follicular lymphoma, but not curative. Combination chemotherapy was tested in the 1970s, but despite high rates of response, there was only minimal impact on survival. Interferon combined with anthracycline based chemotherapy was the first treatment to improve survival, but was not widely adopted in the USA. Randomized studies have shown an impact of autologous transplantation on progression free survival. Allogeneic transplantation is a curative therapy, but is too toxic for widespread application. Targeted therapies, particularly rituximab have revolutionized the treatment of follicular lymphoma. A convergence of technological and biological advances will likely lead to further dramatic progress in the next decade. For the first time consistent improvements in survival of follicular lymphoma are reported.

Relative abundance of full-length and truncated FOXP1 isoforms is associated with differential NFkappaB activity in Follicular Lymphoma

FOXP1 is a transcriptional repressor that has been proposed to repress the expression of some NFkappaB-responsive genes. Furthermore, truncated forms of FOXP1 have been associated with a subtype of Diffuse Large B-cell Lymphoma characterised by constitutive NFkappaB activity, indicating that they may inhibit this repression. We have shown that FL tumors have increased relative abundance of truncated FOXP1 isoforms and this is associated with increased expression of NFkappaB-associated genes. Our results provide strong evidence that relative FOXP1 isoform abundance is associated with NFkappaB activity in FL, and could potentially be used as a marker for this gene signature.

Follicular lymphoma of the spleen: multiparameter analysis of 16 cases

Follicular lymphoma (FL) involving the spleen must be distinguished from reactive hyperplasia and from other lymphomas. A prior study reported that splenic FLs frequently lack BCL2 expression, further complicating diagnosis. We examined 16 cases of splenic FL, including 12 cases initially diagnosed at splenectomy. Two morphologic patterns were identified: one with architectural abnormalities (AA) and one with an extensive architectural preservation (AP) pattern. Newly diagnosed AP cases were associated with older age (P = .051) and grade 1 histologic features (P = .023). All cases displayed a CD10+/BCL2+ phenotype. Cytogenetics and FISH identified IGH/BCL2 or BCL6 translocations in all tested cases. Splenic FLs display phenotypic and cytogenetic findings similar to nodal FLs. However, splenic FLs frequently display an exclusively intrafollicular growth pattern resembling so-called in situ FL. Recognition of subtle FL with preserved architecture is important because patients may have overt FL at other sites or the FL may progress to overt nodal disease.

Radiation therapy with tositumomab (B1) anti-CD20 monoclonal antibody initiates extracellular signal-regulated kinase/mitogen-activated protein kinase-dependent cell death that overcomes resistance to apoptosis

PURPOSE

The use of targeted radiation therapy (RT) in conjunction with anti-CD20 monoclonal antibodies (mAb) delivers high clinical response rates in B-cell lymphomas as part of radioimmunotherapy. The mechanisms underlying these impressive responses, particularly in patients whose lymphomas have become refractory to chemotherapy, are poorly understood.

EXPERIMENTAL DESIGN

In this study, we have investigated the signaling pathways and mode of cell death induced in B-cell lymphoma cells after the combination of RT and either type I (rituximab) or type II (tositumomab/B1) anti-CD20 mAb.

RESULTS

Increased tumor cell death was observed when RT was combined with tositumomab, but not rituximab. This additive cell death was found to be mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-dependent and could be reversed with mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) inhibitors, as well as small interfering RNA targeting MEK1/2. Furthermore, we found that this increased death was associated with ERK1/2 nuclear accumulation after tositumomab treatment, which was enhanced in combination with RT. Importantly, although Bcl-2 overexpression resulted in resistance to RT-induced apoptosis, it had no effect on the tumor cell death induced by tositumomab plus RT, indicating a nonapoptotic form of cell death.

CONCLUSIONS

These findings indicate that RT and type II anti-CD20 mAb combine to stimulate a prodeath function of the MEK-ERK1/2 pathway, which is able to overcome apoptotic resistance potentially explaining the efficacy of this modality in treating patients with chemoresistant disease.

Therapeutic lymphoma vaccines: importance of T-cell immunity

The unique antigenic determinants, termed idiotype, of the immunoglobulin expressed on a given B-cell malignancy can serve as a tumor-specific antigen for active immunotherapy. Administration of autologous tumor-derived idiotype protein conjugated to a carrier protein, keyhole limpet hemocyanin, together with granulocyte-macrophage colony-stimulating factor to follicular lymphoma patients in complete clinical remission was associated with induction of tumor-specific cellular and humoral immunity, molecular remissions, and prolonged disease-free survival. Idiotype vaccination in patients with mantle cell lymphoma following rituximab-containing chemotherapy induced tumor-specific T-cell immunity in the absence of B cells, suggesting that vaccines may be used in combination with rituximab. Three double-blind, randomized, Phase III idiotype vaccine trials are currently ongoing to definitively determine the clinical benefit of idiotype-keyhole limpet hemocyanin plus granulocyte-macrophage colony-stimulating factor vaccination in patients with lymphoma. Results from early clinical trials with idiotype vaccines suggested that both humoral and cellular immune responses may be independently associated with tumor regression and improved progression-free survival. With the increased use of rituximab for the treatment of follicular lymphoma and other B-cell non-Hodgkin's lymphomas, further improvement in the potency of the vaccines would require strategies to enhance T-cell responses, as rituximab depletes normal B cells and impairs the generation of antibody responses.

Prognostic significance of host immune gene polymorphisms in follicular lymphoma survival

Recent gene-expression data have suggested that host immune genetic signatures may predict outcomes in patients with follicular lymphoma. We evaluated the hypothesis that germ line common variation in candidate immune genes is associated with survival. Cox models were used to estimate hazard ratios (HR) and corresponding 95% confidence intervals for individual SNPs after accounting for age, clinical, and other demographic factors. The median age at diagnosis of the 278 patients was 57 years, and 59 (21%) of the patients died during follow-up, with a median follow-up of 59 months (range, 27-78 months) for surviving patients. SNPs in IL8 (rs4073; HR(TT)=2.14, 1.26-3.63), IL2 (rs2069762; HR(GT/TT) = 1.80, 1.06-3.05), IL12B (rs3212227; HR(AC/CC)=1.83, 1.06-3.06), and IL1RN (rs454078; HR(AA)=1.93, 1.11-3.34) were the most robust predictors of survival. A summary score of the number of deleterious genotypes from these genes was strongly associated with survival (P=.001). A risk score that combined the 4 SNPs with the clinical and demographic factors was even more strongly associated with survival (P<.001); the 5-year Kaplan-Meier survival estimates were 96% (93%-100%), 72% (62%-83%), and 58% (48%-72%) for groups at low, intermediate, and high risk, respectively. Common variation in host immune genes warrants further evaluation as a promising class of prognostic factors in follicular lymphoma.

CD8+ T-cell content in diagnostic lymph nodes measured by flow cytometry is a predictor of survival in follicular lymphoma

PURPOSE

Follicular lymphoma is a heterogeneous disease with variable prognosis and clinical course. We hypothesized that the presence of nonmalignant T cells in the microenvironment of the tumor may affect the outcome.

EXPERIMENTAL DESIGN

Using flow cytometry, we evaluated the T-cell subsets in the lymph node microenvironment of follicular lymphoma. All patients in South Stockholm County with indolent follicular lymphoma and with flow cytometry done on a diagnostic lymph node between 1994 and 2004 were included (N = 139). Diagnosis and grade (1, 2, and 3a) were confirmed by re-review. Flow cytometry results were reanalyzed. Lymphocyte subsets, the Follicular Lymphoma International Prognostic Index, grade, and clinical characteristics were evaluated in univariable and multivariable Cox analysis with respect to overall survival (OS) and disease-specific survival (DSS).

RESULTS

Higher CD8+ T-cell levels correlated with longer OS and DSS, independently of the Follicular Lymphoma International Prognostic Index (OS, P = 0.017; DSS, P = 0.020) and independently of all other prognostic factors (OS, P = 0.001; DSS, P = 0.004). Median OS was not reached for patients in the upper quarter of CD8+ T-cell levels (>8.6%), 10.4 years for patients in the middle half (4.2-8.6%), and 6.0 years for patients in the lower quarter (<4.2%). Furthermore, patients who had not required treatment within 6 months from diagnosis had more CD8+ T cells (P = 0.011).

CONCLUSIONS

Higher levels of CD8+ T cells predict a better prognosis, and these data support an important role for nonmalignant immune cells in the biology of follicular lymphoma. Evaluating the CD8+ T cells by flow cytometry at diagnosis may provide prognostic information.

Gene-expression profiling during curcumin-induced apoptosis reveals downregulation of CXCR4

OBJECTIVE

A dietary compound curcumin hardwires to multiple cellular processes, with suppression of cell proliferation, induction of apoptosis, and inhibition of metastasis considered as the major mechanisms underlying its anticancer properties. Based on our recent evidence that curcumin triggers cell demise in follicular lymphoma (FL) cells, we aimed to identify curcumin-regulated genes of utmost importance for the treatment of follicular lymphoma.

MATERIALS AND METHODS

Large-scale gene-expression profiling was performed during curcumin-triggered apoptosis (8-36 hours) in follicular lymphoma HF4.9 cells using Sentrix Human WG-6 BeadChips. Expression levels of selected differentially expressed genes were verified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and immunoblotting. Chemical inhibitor studies (cyclosporin A and AMD3100) were performed to provide further insights into the functional significance of selected genes.

RESULTS

Comprehensive transcriptional response is associated with curcumin treatment in HF4.9 cells, including differential expression of genes encoding apoptotic signaling proteins, tumor and metastasis suppressors, transcription and splicing factors, proteins involved in regulation of cell adhesion, migration (e.g., CXCR4), lymphoid development, or B-cell activation (e.g. CD20), and others. CXCR4 downregulation was confirmed by both qRT-PCR and immunoblotting. Importantly, curcumin induced downregulation of CXCR4 protein also in other FL cell lines, and similar effect was observed upon prolonged incubation with low concentration of curcumin. AMD3100 (a selective CXCR4 antagonist) alone enhanced neither spontaneous nor serum-starvation-induced death at 24 hours of treatment, but impaired long-term cell growth in a cell line-dependent fashion.

CONCLUSIONS

To our knowledge this is the first study showing curcumin-induced downregulation of CXCR4, and at attainable in vivo concentration of the polyphenol. Other curcumin-regulated genes identified herein, e.g., CD20, are also seemingly pertinent to the pathophysiology of follicular lymphoma.

BiovaxID: a personalized therapeutic cancer vaccine for non-Hodgkin's lymphoma

The clonal immunoglobulin molecule, idiotype (ID), expressed on the surface of B-cell malignancies can function as a tumor-specific antigen. BiovaxID is a patient-specific therapeutic cancer vaccine composed of the tumor idiotype conjugated to a carrier protein, keyhole limpet hemocyanin (KLH). In a Phase II clinical trial, administration of ID-KLH vaccine together with granulocyte-macrophage colony-stimulating factor to follicular lymphoma patients in complete remission induced tumor-specific cellular and humoral immunity and molecular remissions, and was associated with prolonged disease-free survival. A randomized, double-blind, Phase III clinical trial is ongoing to definitively determine the clinical benefit of BiovaxID plus granulocyte-macrophage colony-stimulating factor vaccination in patients with follicular lymphoma.

Vaccine therapy for B-cell lymphomas: next-generation strategies

Active immunotherapy is a promising approach for the treatment of lymphomas. Immunization with the clonal tumor immunoglobulin, idiotype, expressed on the surface of B-cell malignancies was associated with induction of tumor-specific cellular and humoral immunity, molecular remissions, and prolonged disease-free survival in early clinical trials. Idiotype vaccination was also demonstrated to induce tumor-specific T-cell immunity in the absence of B cells following treatment with rituximab-containing chemotherapy, suggesting that vaccines may be used in combination with rituximab. Three double-blind randomized phase 3 idiotype vaccine trials are currently ongoing to definitively determine the clinical benefit of idiotype vaccination in patients with lymphoma. Novel second-generation lymphoma vaccines are in development to streamline the production of patient-specific cancer vaccines and show encouraging results in preclinical and pilot clinical studies. To enhance the clinical efficacy of active immunotherapy, future clinical trials are likely to use a combination strategy with the lymphoma vaccine to stimulate an antitumor T-cell response and the simultaneous suppression of immune regulatory pathways to augment the induced T-cell response.

BCR-bound antigen is targeted to exosomes in human follicular lymphoma B-cells

BACKGROUND INFORMATION

Exosomes are small membrane vesicles secreted by several cell types during exocytic fusion of multivesicular bodies with the plasma membrane. Exosomes from tumour cells can transfer antigens from cell to cell, a property favouring antigen-specific immune responses in vitro and in vivo, and are thus an interesting putative therapeutic tool in human cancers. Exosomes have been well studied in EBV (Epstein-Barr virus)-transformed human B-cell lines; however, biological stimuli regulating exosome secretion quantitatively and/or qualitatively still remain poorly defined.

RESULTS

We analysed the effect of the BCR stimulation on exosome release in the human follicular lymphoma B-cell line DOHH2. We found that BCR (B-cell receptor) triggering of DOHH2 cells induced the polarization of CD63(+) MHC class II compartments. Moreover, BCR stimulation increased the release of exosome-associated proteins in the extracellular space. Finally, we found that the BCR was expressed at the surface of exosomes, and could target a bound anti-human IgG to these vesicles.

CONCLUSIONS

BCR can modulate the protein content of exosomes upon stimulation, and can target its bound antigen to these vesicles.

Pathway-specific apoptotic gene expression profiling in chronic lymphocytic leukemia and follicular lymphoma

Defects in the apoptotic pathway are pathogenetically important in chronic lymphocytic leukemia and follicular lymphoma. To further understand these defects, we profiled the apoptotic gene expression of these two neoplasms. Oligonucleotide arrays with 112 apoptotic genes were used, and data analysis was performed on seven chronic lymphocytic leukemia and 10 follicular lymphoma frozen tumor samples from six and seven patients, respectively. The overall gene expression pattern was strikingly similar among all 17 samples, regardless of the type of lymphoma and history of chemotherapy exposure. MCL1, TNFRSF1B and TNFRSF7 were highly expressed in most cases. The apoptotic gene expression between the groups of untreated chronic lymphocytic leukemia (n=3) and untreated follicular lymphoma (n=6) was also similar (Pearson correlation coefficient, 0.94). Comparison between the groups of untreated chronic lymphocytic leukemia (n=3) and postchemotherapy chronic lymphocytic leukemia (n=4) revealed six genes with >2-fold changes, including BIRC5/Survivin that was higher in the postchemotherapy samples. This finding was validated by immunohistochemistry. Similar analysis of follicular lymphoma cases did not identify any significant differences. To conclude, our findings suggest that chronic lymphocytic leukemia and follicular lymphoma share common apoptotic defects, and highlight the importance of MCL1 and the TNF pathway. Upregulation of survivin may be one of the mechanisms by which chronic lymphocytic leukemia becomes desensitized to chemotherapy.

Non-Hodgkin's lymphoma of the renal pelvis

Primary lymphoma of the upper urinary tract is an extremely rare entity without specific clinical or laboratory findings. Thus, this particular diagnosis is rarely anticipated and might well be reached only after nephroureterectomy. We describe a patient with primary follicular and diffuse follicle center lymphoma arising in the renal pelvis that was treated with surgery and postoperative immunochemotherapy. Furthermore, we review the literature regarding the treatment and outcome of this rare disease.

From Gene Expression Analysis to Tissue Microarrays

Mantle cell lymphoma (MCL) is an aggressive lymphoid malignancy for which better treatment strategies are needed. To identify potential diagnostic and therapeutic targets, a signature consisting of MCL-associated genes was selected based on a comprehensive gene expression analysis of malignant and normal B cells. The corresponding protein epitope signature tags were identified and used to raise monospecific, polyclonal antibodies, which were subsequently analyzed on paraffin-embedded sections of malignant and normal tissue. In this study, we demonstrate that the initial selection strategy of MCL-associated genes successfully allows identification of protein antigens either uniquely expressed or overexpressed in MCL compared with normal lymphoid tissues. We propose that genome-based, affinity proteomics, using protein epitope signature tag-induced antibodies, is an efficient way to rapidly identify a number of disease-associated protein candidates of both previously known and unknown identities.