The role of rituximab and chemotherapy in aggressive B-cell lymphoma: A preliminary report of dose-adjusted EPOCH-R

Navigating between Scylla and Charybdis: A roadmap to do better than Pola-RCHP in DLBCL

In treating diffuse large B-cell lymphoma (DLBCL), oncologists have traditionally relied on the chemotherapy backbone of R-CHOP as standard of care. The two dangers that the hematologist must navigate between are the aggressive disease (Charybdis that in the absence of therapy systematically destroys all the ships) and the toxicity of the therapies (Scylla with its six monstrous heads that devours six crew members at a time), and hematologists have to navigate very carefully between both. Therefore, three different strategies were employed with the goal of improving cure rates: de-escalating regimens, escalating regimens, and replacement strategies. With a replacement strategy, a breakthrough in treatment was identified with polatuzumab vedotin (anti-CD79B antibody/drug conjugate) plus R-CHP. However, this regimen still did not achieve the elusive universal cure rate. Fortunately, advances in genomic and molecular technologies have allowed for an improved understanding of the heterogenous molecular nature of the disease to help develop and guide more targeted, precise, and individualized therapies. Additionally, new pharmaceutical technologies have led to the development of novel cellular therapies, such as chimeric antigen receptor (CAR) T-cell therapy, that could be more effective, while maintaining an acceptable safety profile. Thus, we aim to highlight the challenges of DLBCL therapy as well as the need to address therapeutic regimens eventually no longer tethered to a chemotherapy backbone. In the intersection of artificial intelligence and multi-omics (genomics, epigenomics, transcriptomics, proteomics, metabolomics), we propose the need to analyze multidimensional biologic datato launch a decisive attack against DLBCL in a targeted and individualized fashion.

Primary adrenal insufficiency masking as an adrenal B-cell lymphoma

We report here a woman in her 70s presenting with adrenal insufficiency secondary to a primary adrenal lymphoma. The patient had a previous history of aphthous ulcers on dexamethasone and was referred to endocrinology with symptoms of fatigue and orthostasis. Subsequent Cosyntropin stimulation showed primary adrenal insufficiency and adrenal CT demonstrated large infiltrative masses. Adrenal biopsy confirmed the diagnosis of primary adrenal lymphoma of the B-cell type. This case demonstrates the importance of including lymphoma in the differential diagnosis of adrenal insufficiency, particularly in the elderly population and in the setting of negative 21-hydroxlyase antibody results.

Phase 1b/2 study of ibrutinib and lenalidomide with dose-adjusted EPOCH-R in patients with relapsed/refractory diffuse large B-cell lymphoma

Relapsed/refractory diffuse large B-cell lymphoma (DLBCL) is difficult to cure; non-germinal center B-cell-like (non-GCB) and activated B-cell-like (ABC) DLBCL have worse outcomes than GCB DLBCL. Ibrutinib and lenalidomide are synergistic in vitro in ABC DLBCL and may augment salvage chemotherapy. In part 1 of this phase 1b/2 study (NCT02142049), patients with relapsed/refractory DLBCL received ibrutinib 560 mg and escalating doses of lenalidomide on Days 1-7 with DA-EPOCH-R (Days 1-5) in 21-day cycles. In part 1 (N = 15), the maximum tolerated dose was not reached with lenalidomide 25 mg (recommended part 2 dose [RP2D]); most common grade ≥3 adverse events were anemia (73%) and febrile neutropenia (47%); the overall response rate (ORR) was 40%. At the RP2D (n = 26), ORR was 71% in non-GCB and 64% in ABC. Ibrutinib and lenalidomide with DA-EPOCH-R had a manageable safety profile and antitumor activity in relapsed/refractory DLBCL, especially the non-GCB subtype.

Outcomes of treatment with CHOP and EPOCH in patients with HIV associated NHL in a low resource setting

BACKGROUND

The optimal chemotherapy regimen for treating HIV associated NHL in low resource settings is unknown. We conducted a retrospective study to describe survival rates, treatment response rates and adverse events in patients with HIV associated NHL treated with CHOP and dose adjusted-EPOCH regimens at the Uganda Cancer Institute.

METHODS

A retrospective study of patients diagnosed with HIV and lymphoma and treated at the Uganda Cancer Institute from 2016 to 2018 was done.

RESULTS

One hundred eight patients treated with CHOP and 12 patients treated with DA-EPOCH were analysed. Patients completing 6 or more cycles of chemotherapy were 51 (47%) in the CHOP group and 8 (67%) in the DA-EPOCH group. One year overall survival (OS) rate in patients treated with CHOP was 54.5% (95% CI, 42.8-64.8) and 80.2% (95% CI, 40.3-94.8) in those treated with DA-EPOCH. Factors associated with favourable survival were BMI 18.5-24.9 kg/m2, (p = 0.03) and completion of 6 or more cycles of chemotherapy, (p < 0.001). The overall response rate was 40% in the CHOP group and 59% in the DA-EPOCH group. Severe adverse events occurred in 19 (18%) patients in the CHOP group and 3 (25%) in the DA-EPOCH group; these were neutropenia (CHOP = 13, 12%; DA-EPOCH = 2, 17%), anaemia (CHOP = 12, 12%; DA-EPOCH = 1, 8%), thrombocytopenia (CHOP = 7, 6%; DA-EPOCH = 0), sepsis (CHOP = 1), treatment related death (DA-EPOCH = 1) and hepatic encephalopathy (CHOP = 1).

CONCLUSION

Treatment of HIV associated NHL with curative intent using CHOP and infusional DA-EPOCH is feasible in low resource settings and associated with > 50% 1 year survival.

Dose-Adjusted EPOCH-R Compared With R-CHOP as Frontline Therapy for Diffuse Large B-Cell Lymphoma: Clinical Outcomes of the Phase III Intergroup Trial Alliance/CALGB 50303

PURPOSE

Alliance/CALGB 50303 (NCT00118209), an intergroup, phase III study, compared dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (DA-EPOCH-R) with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) as frontline therapy for diffuse large B-cell lymphoma.

PATIENTS AND METHODS

Patients received six cycles of DA-EPOCH-R or R-CHOP. The primary objective was progression-free survival (PFS); secondary clinical objectives included response rate, overall survival (OS), and safety.

RESULTS

Between 2005 and 2013, 524 patients were registered; 491 eligible patients were included in the final analysis. Most patients (74%) had stage III or IV disease; International Prognostic Index (IPI) risk groups included 26% IPI 0 to 1, 37% IPI 2, 25% IPI 3, and 12% IPI 4 to 5. At a median follow-up of 5 years, PFS was not statistically different between the arms (hazard ratio, 0.93; 95% CI, 0.68 to 1.27; P = .65), with a 2-year PFS rate of 78.9% (95% CI, 73.8% to 84.2%) for DA-EPOCH-R and 75.5% (95% CI, 70.2% to 81.1%) for R-CHOP. OS was not different (hazard ratio, 1.09; 95% CI, 0.75 to 1.59; P = .64), with a 2-year OS rate of 86.5% (95% CI, 82.3% to 91%) for DA-EPOCH-R and 85.7% (95% CI, 81.4% to 90.2%) for R-CHOP. Grade 3 and 4 adverse events were more common (P < .001) in the DA-EPOCH-R arm than the R-CHOP arm, including infection (16.9% v 10.7%, respectively), febrile neutropenia (35.0% v 17.7%, respectively), mucositis (8.4% v 2.1%, respectively), and neuropathy (18.6% v 3.3%, respectively). Five treatment-related deaths (2.1%) occurred in each arm.

CONCLUSION

In the 50303 study population, the more intensive, infusional DA-EPOCH-R was more toxic and did not improve PFS or OS compared with R-CHOP. The more favorable results with R-CHOP compared with historical controls suggest a potential patient selection bias and may preclude generalizability of results to specific risk subgroups.

Evaluation of a method for calculating carboplatin dosage in DeVIC ± R therapy (combination therapy of dexamethasone, etoposide, ifosfamide and carboplatin with or without rituximab) as a salvage therapy in patients with relapsed or refractory non-Hodgkin lymphoma

PURPOSE

Several studies have evaluated the utility of extrapolating the Calvert formula in calculating carboplatin (CBDCA) dosages in solid tumours; however, data regarding haematological cancers are less. Therefore, we conducted a preliminary study of the utility of extrapolating the Calvert formula in calculating CBDCA dosages for DeVIC ± R therapy.

METHODS

A retrospective study on 57 non-Hodgkin lymphoma patients who had received DeVIC ± R therapy was conducted. The area under the curve (AUC) of CBDCA was back-calculated from actual dosages using the Calvert formula. Patients were divided into two groups according to an AUC ≥ 4 or an AUC < 4, respectively. The Revised Response Criteria of the International Working Group and CTCAE version 4.0 were used for assessing the treatment efficacy and adverse events, respectively.

RESULTS

The use of AUC instead of body surface area had greater utility in calculating CBDCA dosage, with a response rate of greater than 50 % in patients receiving DeVIC ± R therapy with an AUC ≥ 4 for CBDCA. The response rate of the AUC ≥ 4 group was significantly higher than that of the AUC < 4 group. Decreased platelet and neutrophil counts of grade ≥3 occurred at higher rates in the AUC ≥ 4 group.

CONCLUSION

The extrapolation of the Calvert formula has utility in calculating the CBDCA dosage for DeVIC ± R therapy, and therapeutic efficacy was increased by maintaining the AUC of CBDCA at ≥4.

Targeted Therapies for the Treatment of Pediatric Non-Hodgkin Lymphomas: Present and Future

Pediatric Non-Hodgkin Lymphomas (NHL) are a diverse group of malignancies and as such treatment can vary based on the different biological characteristics of each malignancy. Significant advancements are being made in the treatment and outcomes of this group of malignancies. This is in large part due to novel targeted drug therapies that are being used in combination with traditional chemotherapy. Here, we discuss several new lines of therapy that are being developed or are in current use for pediatric patients with NHL.

Rare case of primary pleural lymphoma presenting with pleural effusion

Primary pleural lymphoma is rare and has been described in association with human immunodeficiency virus (HIV) infection or pyothorax. We report a rare case of primary pleural lymphoma in a 73-year-old man who presented with chest pain and no history of HIV infection or pyothorax. Chest imaging showed pleural thickening and pleural effusion. Thoracoscopic pleural biopsy was performed. Histopathological and immunohistochemical examinations conformed to that of a diffuse large B-cell lymphoma. Physicians should be aware of this rare location of primary lymphoma and implement thoracoscopy as soon as possible.

Risk and prophylaxis strategy of hepatitis B virus reactivation in patients with lymphoma undergoing chemotherapy with or without rituximab

Hepatitis B virus (HBV) reactivation is a serious but preventable complication for patients with lymphoma receiving systemic therapy. Without antiviral prophylaxis, the HBV reactivation rate is estimated to be > 50% in patients who are positive for hepatitis B surface antigen (HBsAg), and fatal hepatic failure is not uncommon. Current guidelines suggest that routine antiviral prophylaxis should be administered to all HBsAg-positive patients until 6-12 months after completion of chemotherapy. For those who are negative for HBsAg and positive for hepatitis B core antibody, HBV reactivation is uncommon when a conventional dose of chemotherapy is administered. However, with rituximab-containing immunochemotherapy, the HBV reactivation rate is 18% and the clinical course can vary from asymptomatic viremia to fulminant hepatic failure that can be potentially fatal. In this review, we discuss the risk, clinical course and prophylactic strategy of HBV reactivation in patients with lymphoma treated with chemotherapy with or without rituximab.

The status of radioimmunotherapy in CD20+ non-Hodgkin's lymphoma

Rituximab, the CD20-directed antibody, has become a standard component of treatment regimens for patients with B cell non-Hodgkin's lymphoma (NHL). The use of rituximab has resulted in greatly improved response and survival rates with less toxicity relative to standard chemotherapeutic regimes. However, relapse and recurrence is common, particularly in indolent varieties which remain incurable, requiring alternate therapeutic options. The subsequent coupling of β-emitting isotopes such as (131)I and (90)Y to anti-CD20 monoclonal antibodies (mAbs), including rituximab, has been steadily growing over the last decade and demonstrates even greater therapeutic efficacy with more durable responses. (177)Lutetium-labelled rituximab offers a number of convenient advantages over (131)I and (90)Y anti-CD20 mAbs for treatment of NHL, and a number of alpha-emitting isotopes lie at the frontier of consolidation therapy for residual, micrometastatic disease.

Primary mediastinal large B-cell lymphoma, classic Hodgkin lymphoma presenting in the mediastinum, and mediastinal gray zone lymphoma: what is the oncologist to do?

In recent years, an overlap in biologic and clinical features has been identified between classic Hodgkin lymphoma (CHL) and primary mediastinal large B-cell lymphoma (PMBL). Further strengthening this relationship is the identification of lymphomas with clinical and morphologic features transitional between the two, known as gray zone lymphomas (GZL). However, this diagnostic gray zone is not just of theoretical interest: it presents a practical problem, as the treatment approaches for CHL traditionally differ from those for aggressive B-cell lymphomas. This article reviews the treatment approach for mediastinal lymphomas, including CHL of the nodular sclerosis subtype (CHL-NS), PMBL, and mediastinal GZL. Though several trials have evaluated different regimens with or without radiation in PMBL and CHL-NS, there is a lack of prospective experience in treating GZL because of the rarity of these tumors. Historical data indicate that they have done poorly with traditional approaches developed for the treatment of either CHL or diffuse large B-cell lymphoma.

Dexamethasone, High-Dose Cytarabine, and Cisplatin in Combination with Rituximab as Salvage Treatment for Patients with Relapsed or Refractory Aggressive Non-Hodgkin's Lymphoma

We designed a multicenter Phase II trial to prospectively evaluate the efficacy and safety of the combination of rituximab with the DHAP regimen (dexamethasone, high-dose cytarabine, cisplatin) in patients who relapsed after or were resistant to a CHOP-like regimen. A total of 53 patients with relapsed or resistant aggressive B-cell NHL were analyzed. The overall response rate was 62.3 percent. With a median follow-up of 24.9 months, median overall and progression-free survivals were 8.5 and 6.7 months, respectively. Immunochemotherapy with rituximab and DHAP proved to be feasible and effective in this patient population.

Overview of lymphoma diagnosis and management

The malignant lymphomas, including both Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), represent a diverse group of diseases that arise from a clonal proliferation of lymphocytes. Each of the more than 30 unique types of lymphoma is a disease with a distinct natural history. This biologic heterogeneity gives rise to marked differences among the lymphomas with respect to epidemiology, pathologic characteristics, clinical presentation, and optimal management. This article emphasizes the principles of diagnosis, including appropriate pathologic evaluation and staging considerations, and focuses on the clinical presentation, staging, and optimal management strategies for the most common types of lymphoma.

Current treatment approaches for diffuse large B-cell lymphoma

There have been two major developments over the last decade that has led to improvements in outcome and longer survival for patients with diffuse large B-cell lymphoma (DLBCL). These developments have been firstly to increase the dose of active cytotoxic drugs and shorten the time between cycles, resulting in dose-dense and/or dose-intense regimens and secondly the addition of the anti-CD20 monoclonal antibody rituximab to chemotherapy. Both strategies have been associated with higher response rates, lower relapse rates, longer event-free survival (EFS) and improved overall survival (OS), particularly in better prognostic groups. A combination of dose-dense and dose-intense chemotherapy regimens plus rituximab is currently being tested to confirm that the use of both approaches confers survival advantage. High-risk, poorer-prognosis DLBCL remains a challenge, and new treatment strategies are required for these patients. Improvements in outcome may potentially be achieved through a greater understanding of the genetic abnormalities specifically associated with poorer-prognosis disease, and factors that lead to unresponsiveness to chemotherapy. The role of radiotherapy is currently less clearly defined than at anytime in the management of DLBCL and the current evidence for using radiotherapy in this disease is therefore rigorously reviewed.

The efficacy of rituximab in high-grade pediatric B-cell lymphoma/leukemia: a review of available evidence

PURPOSE OF REVIEW

This review evaluates whether rituximab has efficacy in high-grade pediatric B-cell lymphoma/leukemia. Current pediatric protocols for CD20+ B-cell lymphoma/leukemia significantly improve survival, but with major morbidity. To assess whether rituximab has efficacy in very high-grade pediatric disease, all published data on rituximab therapy for Burkitt's lymphoma/B acute lymphoblastic leukaemia (B-ALL) and pediatric patients with relapsed/refractory large B-cell lymphoma were reviewed.

RECENT FINDINGS

Three trials in adult Burkitt's/B-ALL showed a significant survival advantage when rituximab was added to standard chemotherapy. Minimal pediatric data have been published, but 19 children with mature B-cell lymphoma/B-ALL received rituximab, alone or in combination with chemotherapy, as salvage therapy, after failure of intensive chemotherapy. Fifteen of 19 (79%) responded, 12 (63%) remained alive in continuous complete remission at 5+ to 48+ months of follow-up. Two patients were alive in partial remission. Five patients died, four of progressive disease. Only one patient had no response to rituximab.

SUMMARY

Rituximab has demonstrated efficacy in Burkitt's disease in adults. Although positive reporting bias is suspected, it appears that rituximab, even as monotherapy, has efficacy in heavily pretreated pediatric patients with high-grade B-lymphoma/B-ALL. Rituximab use can be justified in a prospective controlled chemotherapy dose-reduction study.

Primary diffuse large B-cell lymphoma of the spleen with coincident serous retinal detachments responsive to corticosteroids

Non-Hodgkin's lymphoma is the sixth leading cause of cancer death in the USA. Herein, a patient is presented with primary diffuse large B-cell lymphoma whose initial complaint was blurred vision and who presented with corticosteroid-responsive serous retinal detachments mimicking Vogt-Koynagi-Harada. Extensive clinical examination including imaging and blood testing was negative. Splenectomy led to a diagnosis of splenic lymphoma.

Dose-adjusted EPOCH plus rituximab is an effective regimen in patients with poor-prognostic untreated diffuse large B-cell lymphoma: results from a prospective observational study

This study was designed to assess the efficacy and safety of an infusional DA-EPOCH (dose-adjusted etoposide/vincristine/doxorubicin/bolus cyclophosphamide/prednisone) and rituximab (DA-EPOCH-R) regimen for patients with poor prognosis diffuse large B-cell lymphoma (DLBCL). Thirty-three patients, aged 21-76 years, with an age-adjusted International Prognostic Index (IPI) of 2 or 3, were enrolled, and 31/33 patients were evaluable for response. Consolidative radiation therapy was given to eight patients with bulky (> or =10 cm) disease at presentation. Overall, 26 patients (83.8%) achieved a complete remission (CR), four patients (12.9%) achieved a partial remission, and one patient (3.2%) died during induction. Two patients relapsed (7.6%) within 15 months. Grade 3-4 neutropenia developed in 52% of cycles and neutropenic fever in 14% of cycles (51% of patients). The estimates for event-free survival (EFS) and overall survival at 2 years were 68% and 75% respectively. The only factor related to poor EFS was the presence of three age-adjusted IPI-risk factors. We conclude that DA-EPOCH-R has clinically significant activity with a favourable toxicity profile for poor-prognostic DLBCL patients. The administration of DA-EPOCH-R as an outpatient regimen by using a single portable infusion pump may be a feasible alternative to improve the compliance and to reduce the total cost of this very effective regimen.

Standard treatment of advanced-stage diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most frequent lymphoma and is not localized in 70% of the cases. Even if the clinical picture, the morphologic aspect, and the prognostic parameters are different from one patient to another, the standard treatment is the same for all patients. Currently, treatment decision is based on the International Prognostic Index (IPI) and age of the patient. Outcome has been completely modified with the introduction of rituximab in combination with chemotherapy. A review of standard treatment and remaining questions is presented.

Radiofrequency ablation of lymphoma

Percutaneous minimally invasive radiofrequency (RF) ablation has not been described for lymphoma. This image-guided modality is presented in 3 different settings for the treatment of refractory lymphoma. The first patient received RF ablation for the curative treatment of a solitary residual hepatic mass following rituximab-based chemotherapy for a posttransplantation lymphoproliferative disorder (PTLD) and is disease-free 4 years later. The second patient received RF ablation for successful palliation of progressive follicular lymphoma adjacent to the bladder wall following chemotherapy and maximum radiation. The third patient received RF ablation for prevention of airway obstruction from progressive diffuse large B-cell lymphoma of the right neck following chemotherapy and maximum radiation. RF ablation may be clinically beneficial and should be considered for the treatment of local lymphoma that is refractory or not amenable to standard approaches.

Mediastinal gray zone lymphoma: the missing link between classic Hodgkin's lymphoma and mediastinal large B-cell lymphoma

In recent years, overlap in biologic and morphologic features has been identified between classic Hodgkin lymphoma (cHL) and B-cell non-Hodgkin lymphoma. Nevertheless, the therapeutic approaches for these diseases remain different. We undertook a study of "mediastinal gray zone lymphomas" (MGZL), with features transitional between cHL nodular sclerosis (NS) and primary mediastinal large B-cell lymphoma (MLBCL) to better understand the morphologic and immunophenotypic spectrum of such cases. Twenty-one MGZL cases were identified over a 20-year period. We also studied 6 cases of composite or synchronous lymphoma with two distinct components at the same time (cHL-NS and MLBCL) and 9 sequential cases with MLBCL and cHL-NS at different times. All patients had a large mediastinal mass. Immunohistochemical studies focused on markers known to discriminate between cHL and MLBCL, including B-cell transcription factors. VJ-PCR was performed in 8 cases to look at clonality of the immunoglobulin heavy chain gene (IgH). Of the gray zone cases, 11 had morphology reminiscent of cHL-NS, but with unusual features, including a large number of mononuclear variants, diminished inflammatory background, absence of classic Hodgkin phenotype, and strong CD20 expression (11 of 11). Ten cases had morphology of MLBCL, but with admixed Hodgkin/Reed-Sternberg and lacunar cells, absent (3 of 10) or weak (7 of 10) CD20 expression, and positivity for CD15 in 7 cases. B-cell transcription factor expression in the gray zone cases more closely resembled MLBCL than cHL with expression of Pax5, Oct2, and BOB.1 in all but 1 case studied (14 of 15). MAL staining was found in 7 of 10 MGZL, and in at least one component of 6 of 7 evaluable composite or sequential MLBCL/cHL cases. Two cases of sequential lymphoma showed rearrangements of the IgH gene of identical size: one in which MLBCL was the first diagnosis and one in which MLBCL was diagnosed at relapse, indicating clonal identity for the two components of cHL and MLBCL. There is accumulating evidence that MLBCL and cHL are related entities. Further support for a relationship between MLBCL and cHL-NS is provided by composite and metachronous lymphomas in the same patient, as well as the existence of MGZL with transitional morphology and phenotype.

State-of-the-art therapeutics: diffuse large B-cell lymphoma

This article is a review of the improvement in the treatment of patients with diffuse large B-cell lymphoma made during the last 10 years. Patients with diffuse large B-cell lymphoma now have a better outcome with longer survival because of two major developments: (1) increasing the dose of active drugs with shortening the time between cycles, resulting in dose-dense and/or dose-intense regimens; and (2) combining rituximab with chemotherapy. Both strategies were associated with higher response rates, lower relapse rates, longer event-free survival, longer time to progression, and longer overall survival, particularly in patients without adverse prognostic parameters. A combination of dose-dense, dose-intense regimens plus rituximab is currently being tested for poor-risk patients with diffuse large B-cell lymphoma. However, much work has to be done for patients with high-risk lymphoma. It may come with a better definition of genetic abnormalities specifically associated with refractoriness to chemotherapy.

Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma

The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell-dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody-based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4(+) and CD8(+) antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.

Long-term results of the R-CHOP study in the treatment of elderly patients with diffuse large B-cell lymphoma: a study by the Groupe d'Etude des Lymphomes de l'Adulte

PURPOSE

To analyze the long-term outcome of patients included in the Lymphome Non Hodgkinien study 98-5 (LNH98-5) comparing cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) to rituximab plus CHOP (R-CHOP) in elderly patients with diffuse large B-cell lymphoma.

PATIENTS AND METHODS

LNH98-5 was a randomized study that included 399 previously untreated patients, age 60 to 80 years, with diffuse large B-cell lymphoma. Patients received eight cycles of classical CHOP (cyclophosphamide 750 mg/m(2), doxorubicin 50 mg/m(2), vincristine 1.4 mg/m(2), and prednisone 40 mg/m(2) for 5 days) every 3 weeks. In R-CHOP, rituximab 375 mg/m(2) was administered the same day as CHOP. Survivals were analyzed using the intent-to-treat principle.

RESULTS

Median follow-up is 5 years at present. Event-free survival, progression-free survival, disease-free survival, and overall survival remain statistically significant in favor of the combination of R-CHOP (P = .00002, P < .00001, P < .00031, and P < .0073, respectively, in the log-rank test). Patients with low-risk or high-risk lymphoma according to the age-adjusted International Prognostic Index have longer survivals if treated with the combination. No long-term toxicity appeared to be associated with the R-CHOP combination.

CONCLUSION

Using the combination of R-CHOP leads to significant improvement of the outcome of elderly patients with diffuse large B-cell lymphoma, with significant survival benefit maintained during a 5-year follow-up. This combination should become the standard for treating these patients.

Blastoid variant of mantle cell lymphoma with lactic acidosis: a case report

Approximately 20% of mantle cell lymphomas (MCL) present with the blastoid variant associated with poor prognosis. Lactic acidosis complicated with hematologic malignancies is seen infrequently and is associated with a poor outcome. Here we report the case of a patient with the blastoid variant of MCL complicated by lactic acidosis and who achieved complete remission through chemotherapy combined with rituximab therapy. A 77-year-old man presented with peripheral blood lymphoma cells, huge splenomegaly, abdominal and mediastinal lymphadenopathy, and pleural effusion. A bone marrow smear showed an increase in large, abnormal lymphoid cells with oval or round nuclei, distinct nucleoli, and abundant basophilic cytoplasm with vacuolization. Splenic sections also showed massive and diffuse infiltration by these cells. Flow cytometry analysis showed these cells to be positive for CD5, CD19, CD20, and kappa chain and negative for CD10 and CD23. A blastoid variant of MCL was diagnosed from the results of histologic, immunohistochemical (cyclin D1), and cytogenetic (chimeric bcl-1/IgH fusion gene) analyses. The patient recovered from the 2 episodes of severe lactic acidosis for which he had been given chemotherapy, and he achieved complete remission after subsequent chemotherapy combined with rituximab treatment.

Pro-apoptotic therapy with the oligonucleotide Genasense (oblimersen sodium) targeting Bcl-2 protein expression enhances the biological anti-tumour activity of rituximab

New strategies have evolved in the treatment of patients with non-Hodgkin's lymphoma (NHL). Anti-sense oligonucleotides (ASO) and monoclonal antibody (mAb) therapy, though proven to be safe and effective, have not demonstrated to be curative when used as single agents. We tested an innovative combination strategy involving various mAbs and ASO against Bcl-2 (G3139) in aggressive preclinical models. G3139, under optimal transfection conditions, decreased the proliferation rate of lymphoma cells by 60-75% when compared with controls. In addition, apoptosis was demonstrated in Raji (25%) and DHL-4 cells (30%) treated with Genasense following downregulation of Bcl-2 protein. Downregulation of Bcl-2 by G3139 was associated with a higher degree of rituximab-associated, complement-mediated cytotoxicity and antibody dependent cellular cytotoxicity when compared with rituximab alone-treated controls. In vivo studies in severe combined immunodeficiency (SCID) mice clearly demonstrated synergistic activity between G3139 and rituximab. Treatment of lymphoma-bearing SCID mice with G3139 for two consecutive days prior to each rituximab dose resulted in better disease control and survival than treatment with either agent alone or controls. Our findings suggest that Bcl-2 downregulation by G3139, followed by the administration of rituximab is an efficient anti-tumour strategy associated with improved survival in lymphoma-bearing SCID mice.

Diffuse Large B-Cell Lymphoma: Risk Stratification and Management of Relapsed Disease

The clinical factors described by the International Prognostic Index (IPI) provide a model for risk stratification in diffuse large B-cell lymphomas (DLBCLs). However, there is variability in outcome within IPI risk groups, indicating the biological and clinical heterogeneity of these diseases. Studies of gene expression profiling (GEP) in DLBCL are uncovering biological heterogeneity with prognostic significance. Various gene expression signatures with predictive value independent of the IPI are now recognized. Immunophenotypic features of DLBCL have also been shown to have prognostic value. The use of fluorodeoxyglucose–positron emission tomography (FDG-PET) scanning may provide additional predictive information when used at diagnosis or soon after initiation of treatment. Future prognostic models in DLBCL are likely to incorporate functional imaging, immunophenotype and GEPs as well as clinical data in risk stratification and choice of treatment.

Treatment of relapsed DLBCL remains a major problem. High-dose therapy (HDT) and stem cell transplantation (SCT) has been shown to produce superior overall survival (OS) compared with conventional dose salvage therapy in patients with relapsed, chemosensitive DLBCL. However, only 20% to 30% of patients are cured by this approach, and the effectiveness of HDT and SCT in patients treated with rituximab-based combinations as first-line therapy is unknown. Although new transplant techniques including non-myeloablative allogeneic SCT are being investigated, their role is unclear. New treatment strategies are needed for these patients. The use of molecular techniques such as GEP is identifying many potential new therapeutic targets in DLBCL including histone deacetylase, HLA-DR, bcl-2, bcl-6, mTOR and TRAIL.

Current treatment options in aggressive lymphoma

The overall percentage of patients achieving long-term remissions in aggressive non-Hodgkin's lymphoma (NHL) using CHOP or CHOP-based primary chemotherapy is only 40%. Much effort has therefore been concentrated on developing strategies to improve this figure. More intensive variants of CHOP chemotherapy, such as multi-agent "third-generation" regimens, have failed to improve long-term survival, and are also associated with increased toxicity. Hence, there is a need for improved treatment regimens, both as primary therapy and for patients in first and subsequent relapse. This need is most acute in elderly patients (> 60 years of age), who comprise more than 50% of NHL cases and who may not be able to tolerate subsequent intensive chemotherapy at relapse. Approaches currently being examined to improve outcome include: the use of clinical, histological and molecular prognostic factors to establish a patient's risk group, and so define those patients most likely to benefit from early aggressive therapy; the inclusion of high-dose therapy and autologous transplantation; and the integration of novel therapies, such as immunotherapy and radioimmunotherapy, into existing treatment strategies. The impact of these approaches on the treatment of diffuse, large B-cell lymphoma and mantle cell lymphoma is discussed below.

Rituximab: expanding role in therapy for lymphomas and autoimmune diseases

Rituximab (Rituxan) is a human-mouse chimeric monoclonal antibody that targets the B-cell CD20 antigen and causes rapid and specific B-cell depletion. Rituximab was approved in the United States in 1997 to treat low-grade or follicular, relapsed or refractory, CD20-positive B-cell non-Hodgkin's lymphoma (NHL). Since then, further clinical experience with rituximab has been incorporated into the prescribing information, which now stipulates an extended eight-week schedule, treatment of patients with refractory or relapsed bulky disease measuring >10 cm, and retreatment of patients who responded to rituximab previously. In 1998, the European Union approved rituximab (MabThera) to treat stage III/IV, follicular, chemotherapy-resistant, or relapsed NHL. Recently, the European Union also approved the use of rituximab in combination with standard chemotherapy for aggressive NHL. Many clinical trials have evaluated rituximab, alone or with other therapies, in indolent and aggressive NHL as well as other B-cell lymphoproliferative disorders. New studies are evaluating rituximab's role in first-line therapy, maintenance therapy, and stem-cell transplantation procedures. The use of rituximab against autoimmune disorders, such as rheumatoid arthritis, immune thrombocytopenic purpura, autoimmune hemolytic anemia, systemic lupus erythematosus, and multiple sclerosis, is also under investigation.

Rituximab–EPOCH, an effective salvage therapy for relapsed, refractory or transformed B-cell lymphomas: results of a phase II study

BACKGROUND

Relapsed or refractory diffuse large B-cell and mantle-cell lymphoma have a poor prognosis. The EPOCH regimen and rituximab monotherapy have demonstrated activity as salvage therapies. Because of their non-overlapping toxicity, we evaluated their combination as salvage therapy in a phase II study.

PATIENTS AND METHODS

Patients with relapsed or refractory CD20-positive large B-cell and mantle-cell lymphoma were offered treatment with rituximab 375 mg/m2 intravenously (i.v.) on day 1, doxorubicin 15 mg/m2 as a continuous i.v. infusion on days 2-4, etoposide 65 mg/m2 as a continuous i.v. infusion on days 2-4, vincristine 0.5 mg as a continuous i.v. infusion on days 2-4, cyclophosphamide 750 mg/m2 i.v. on day 5 and prednisone 60 mg/m2 orally on days 1-14.

RESULTS

Fifty patients, with a median age of 56 years (range 23-72), entered the study. Twenty-five had primary diffuse large B-cell lymphoma, 18 transformed large B-cell lymphoma and seven mantle-cell lymphoma. The median number of prior chemotherapy regimens was 1.7 (range one to four). The median number of treatment cycles was four (range one to six). Possible treatment-related death occurred in two patients. Objective responses were obtained in 68% of patients (28% complete responses, 40% partial responses). Nineteen patients received consolidating high-dose chemotherapy with autologous stem-cell transplantation. The median follow-up was 33 months. Three patients developed a secondary myelodysplastic syndrome. The median overall survival was 17.9 months; the projected overall survival at 1, 2 and 3 years was 66, 42 and 35%, respectively. The median event-free survival was 11.8 months; the projected event-free survival at 1, 2 and 3 years was 50, 30 and 26%, respectively.

CONCLUSION

The rituximab-EPOCH regimen is effective and well tolerated, even in extensively pretreated patients with relapsed or refractory large B-cell lymphoma and mantle-cell lymphoma.

Rituximab as adjuvant to high-dose therapy and autologous hematopoietic cell transplantation for aggressive non-Hodgkin lymphoma

Based on the favorable safety profile and the independent activity of rituximab in B-cell lymphoma, we evaluated its efficacy and toxicity after high-dose therapy (HDT) and autologous hematopoietic cell transplantation (HCT). Thirty-five patients with diffuse large cell (25 patients), mantle cell (3 patients), transformed (3 patients), or other (4 patients) subtypes of B-cell lymphoma received HDT followed by a purged autologous graft. The rituximab schedule was 4 weekly infusions (375 mg/m(2)) starting at day 42 after HCT and, for patients 5 to 35, a second 4-week course 6 months after HCT. All planned therapy was completed in 29 patients. With 30 months' median follow-up, the 2-year event-free survival (EFS) rate was 83% and the overall survival (OS) rate was 88%. For 21 patients with relapsed or refractory large cell lymphoma, the EFS rate was 81% and the OS rate was 85%. Grades 3 to 4 neutropenia occurred in 19 (54%) patients. A prospective study of immune reconstitution included measurements of lymphocyte subsets, immunoglobulins, and response to vaccination. Serious infections were not observed despite delayed B-cell recovery in all patients and suppressed immunoglobulin G (IgG) levels and low pneumococcus antibody titers in a subset. Rituximab after HDT and HCT is feasible, and these phase 2 data support the current US Intergroup phase 3 trial in recurrent/refractory diffuse large cell lymphoma.

Circulating CD20 and CD52 in patients with non-Hodgkin's lymphoma or Hodgkin's disease

The cell surface proteins CD20 and CD52 differ significantly in their structures and are expressed on the majority of B cells. Both circulating CD20 (cCD20) and circulating CD52 (cCD52) have been recently documented in patients with chronic lymphocytic leukaemia. A retrospective study to establish whether cCD20 and/or cCD52 were detectable in patients with lymphoma, and the clinical associations of these soluble antigens if detected, was conducted. cCD20 and cCD52 levels were analysed in a cohort of 65 patients with non-Hodgkin's lymphoma (NHL) and 37 with Hodgkin's disease (HD). Patients with NHL had elevated pretherapy levels of cCD20 and cCD52 compared with normal individuals. Patients with HD had significantly lower than normal pretherapy levels of both cCD20 and cCD52. cCD20 levels were marginally elevated post-therapy in NHL patients while in patients with HD, cCD20 levels remained significantly lower than normal after therapy. Serum cCD52 levels became significantly lower than normal post-therapy in NHL patients, and remained significantly lower than normal in HD patients. No predictive effects were found for pretherapy or post-therapy levels of cCD52 on survival for either cohort of patients. Post-therapy cCD20 levels independently highly correlated with survival in patients with NHL. Prospective evaluation will be required to establish if cCD20 and cCD52 may be used as biomarkers in the diagnosis, prognostic categorization, and monitoring of the clinical course in patients with lymphoma. The clinical significance of circulating antigen in patients receiving monoclonal antibody therapy directed against CD20 and/or CD52 warrants study.

Monoclonal antibody therapy for lymphoma

Monoclonal antibodies are an exciting advance in the treatment of lymphoma. They are safe and well-tolerated, and exhibit little cross-resistance with conventional chemotherapeutic agents. In indolent lymphomas, antibody therapy has shown useful response rates, both as first-line therapy and in relapsed disease. Follicular lymphomas appear to be particularly sensitive to rituximab, and chronic lymphocytic leukaemia to alemtuzumab. In aggressive lymphomas, the addition of rituximab to CHOP chemotherapy significantly lengthens disease-free and overall survival compared to CHOP alone as first-line therapy. Newer agents, including radiolabelled antibodies, immunotoxin-linked antibodies and antibodies against novel target antigens are showing promise in phase I and II trials in a variety of clinical settings.

Antibodies for the treatment of diffuse large cell lymphoma

The development of monoclonal antibodies has significantly affected the therapy of B-cell non-Hodgkin's lymphomas (NHLs). Rituximab, a chimeric monoclonal antibody directed against the CD20 antigen, has activity in both indolent and aggressive B-cell lymphomas. Perhaps the greatest change has occurred in first-line therapy of advanced stage, diffuse large cell lymphoma (DLCL), where rituximab combined with conventional chemotherapy has improved both overall survival (OS) and progression-free survival (PFS) over combination chemotherapy alone. Further studies are needed assessing the role of rituximab in salvage therapy, as part of the conditioning regimen prior to autologous stem cell transplant, and as maintenance therapy for large cell lymphoma. Several novel monoclonal antibodies are in development and may also be active in DLCL. These agents may be most promising when combined with either chemotherapy or with rituximab. This review will summarize the use of rituximab in the therapy of diffuse large B-cell lymphoma and briefly describe antibodies in development.

Rituximab: a review of its use in non-Hodgkin's lymphoma and chronic lymphocytic leukaemia

Rituximab is an anti-CD20 monoclonal antibody that has demonstrated efficacy in patients with various lymphoid malignancies, including indolent and aggressive forms of B-cell non-Hodgkin's lymphoma (NHL) and B-cell chronic lymphocytic leukaemia (CLL). While the optimal use of the drug in many clinical settings has yet to be clarified, two pivotal trials have established rituximab as a viable treatment option in patients with relapsed or refractory indolent NHL, and as a standard first-line treatment option when combined with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) chemotherapy in elderly patients with diffuse large B-cell lymphoma (the most common type of aggressive NHL). The former was a noncomparative trial in relapsed indolent NHL (follicular and small lymphocytic subtypes) with clinical responses achieved in about half of patients treated with rituximab 375 mg/m(2) intravenously once weekly for 4 weeks, which was similar to some of the most encouraging results reported with traditional chemotherapeutic agents. The latter was a randomised comparison of eight cycles of CHOP plus rituximab 375 mg/m(2) intravenously (one dose per cycle) versus CHOP alone in previously untreated elderly patients (60 to 80 years of age) with diffuse large B-cell lymphoma. In this pivotal trial, 2-year event-free and overall survival were significantly higher with rituximab plus CHOP, and there was no increase in clinically significant adverse effects compared with CHOP alone. Treatment with rituximab is generally well tolerated, particularly in terms of adverse haematological effects and serious or opportunistic infections relative to standard chemotherapy. Infusion-related reactions occur in the majority of patients treated with rituximab; these are usually mild to moderate flu-like symptoms that decrease in frequency with subsequent infusions. In approximately 10% of patients, however, severe infusion-related reactions develop (e.g. bronchospasm, hypotension). These reactions are usually reversible with appropriate interventions and supportive care but there have been rare reports of fatalities.

CONCLUSIONS

Clinical trials with rituximab indicate that the drug has broad application to B-cell malignancies, although further clarification is needed to determine its optimal use in many of these clinical settings. Importantly, rituximab in combination with CHOP chemotherapy has emerged as a new treatment standard for previously untreated diffuse large B-cell lymphoma, at least in elderly patients. Compared with conventional chemotherapy, rituximab is associated with markedly reduced haematological events such as severe neutropenia, as well as associated infections. Rituximab may be particularly suitable for elderly patients or those with poor performance status, and its tolerability profile facilitates its use in combination with cytotoxic drugs.

PHARMACODYNAMIC PROPERTIES

Rituximab is a mouse/human chimaeric IgG(1)-kappa monoclonal antibody that targets the CD20 antigen found on the surface of malignant and normal B lymphocytes. Although treatment with rituximab induces lymphopenia in most patients, typically lasting about 6 months, a full recovery of B lymphocytes in the peripheral blood is usually seen 9-12 months after therapy, as CD20 is not expressed on haematopoietic stem cells. CD20 is, however, expressed on >90% of B-cell non-Hodgkin's lymphomas (NHL) and to a lesser degree on B-cell chronic lymphocytic leukaemia (CLL) cells. Although not fully elucidated, the cytotoxic effects of rituximab on CD20-positive malignant B cells appears to involve complement-dependent cytotoxicity, complement-dependent cellular cytotoxicity, antibody-dependent cellular cytotoxicity and induction of apoptosis. In addition, in vitro data indicate that rituximab sensitises tumour cells to the effects of conventional chemotherapeutic drugs.

PHARMACOKINETIC PROPERTIES

Serum rituximab concentrations increased in proportion to dose across a wide range of single- and multiple-dose intravenous regimens in patients with B-cell NHL. When administll NHL. When administered at a dose of 375 mg/m(2) once weekly for 4 weeks in a pivotal trial in patients with relapsed or refractory indolent B-cell NHL (follicular or small lymphocytic subtypes), peak serum concentrations essentially doubled from the first (239.1 mg/L) to the fourth (460.7 mg/L) infusion, while elimination half-life (t(1/2)) increased from 76.3 to 205.8 hours (3.2 to 8.6 days). The concomitant increase in serum rituximab concentrations and t(1/2) with each successive infusion may be due, at least in part, to the elimination of circulating CD20-positive B cells and reduction or saturation of CD20-binding sites after the initial infusions of rituximab. The pharmacokinetic properties of rituximab are also characterised by wide inter-individual variability, and serum drug concentrations that are correlated with clinical response. Although pharmacokinetic data are limited in patients with aggressive forms of NHL, such as diffuse large B-cell lymphoma, rituximab appears to have a similar pharmacokinetic profile in these patients to that in patients with indolent B-cell NHL. The pharmacokinetics of rituximab are also reported to be similar whether the drug is administered with or without cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) chemotherapy.

THERAPEUTIC USE

A number of studies have demonstrated efficacy of intravenous rituximab in patients with various lymphoid malignancies of B-cell origin, including indolent (e.g. follicular lymphoma) and aggressive (e.g. diffuse large B-cell lymphoma) forms of NHL, and CLL, but the drug has not yet been approved for use in CLL, and approved indications in NHL vary between countries. In the US, for example, rituximab is available for the treatment of patients with low-grade or follicular, relapsed or refractory, CD20-positive B-cell NHL. In Europe, the drug has similar approval for relapsed or refractory follicular NHL as in the US, but has also been approved for use in combination with CHOP chemotherapy for the most common aggressive form of NHL (CD20-positive, diffuse large B-cell lymphoma). Rituximab was approved for these indications primarily on the basis of results from two pivotal trials. In Japan, rituximab has been approved for indolent B-cell NHL and mantle cell lymphoma (an aggressive form of B-cell NHL), primarily on the basis of results of a Japanese phase II trial. Indolent NHL: Results of several studies evaluating rituximab 375 mg/m(2) once weekly for 4 weeks in patients with indolent forms of B-cell NHL (primarily follicular and small lymphocytic lymphomas) showed objective response (OR) rates ranging from approximately 40-60% in those receiving the drug for relapsed or refractory indolent B-cell NHL, and slightly higher (50-70%) for those receiving rituximab as first-line therapy. In a pivotal trial in 166 patients with relapsed or refractory low-grade or follicular B-cell NHL, intent-to-treat (ITT) analysis showed an OR rate of 48%, and a projected median time to progression of 13 months. Encouraging data are also emerging on the use of rituximab in combination with chemotherapeutic agents (e.g. CHOP, fludarabine-containing regimens) or other drugs (e.g. interferon-alpha2a) in previously untreated patients with indolent forms of B-cell NHL (primarily follicular and small lymphocytic subtypes). Rates for OR were consistently around 95%, with the majority being complete responses (CRs). Follow-up data from a study in 40 patients with low-grade or follicular B-cell NHL treated with rituximab plus CHOP as first-line therapy showed that responses were durable with a progression-free survival and median duration of response >5 years.Bcl-2 gene rearrangement (t14;18) occurs in malignant cells in up to 85% of patients with follicular lymphoma, and minimal residual disease in peripheral blood and bone marrow can be monitored using polymerase chain reaction (PCR). In several studies assessing blood and/or bone marrow, rituximab has achieved molecular response (conversion from PCR-positive to PCR-negative bcl-2 status) in at least half of the patients. Aggressive NHL: Studies with rituximab as monotherapy in aggressive B-cell NHL, a potentially curable disorder, have generally been restricted to patients with relapsed or recurrent disease, since CHOP has traditionally been the standard first-line treatment regimen. However, promising results from phase II monotherapy studies prompted further clinical investigation of rituximab in conjunction with chemotherapy. Thus, most studies with rituximab in patients with aggressive forms of B-cell NHL have involved combination therapy, including a pivotal randomised trial comparing eight cycles of standard CHOP therapy plus rituximab 375 mg/m(2) (one dose per cycle) versus CHOP alone in 399 previously untreated elderly patients (60-80 years of age) with diffuse large B-cell lymphoma. Results of the pivotal trial showed a clear advantage for rituximab plus CHOP versus CHOP in terms of event-free survival (primary endpoint) at 2 years (57% vs 38%, p < 0.001). Overall survival at 2 years (70% vs 57%, p < 0.01) and CR rate (76% vs 63%, p < 0.01) were also higher with the rituximab-CHOP combination. Other, smaller trials with rituximab in combination with CHOP or other chemotherapeutic regimens, either as first-line therapy or for patients with relapsed or refractory aggressive B-cell NHL, have also shown promising results in terms of clinical response rates.CLL: In relatively small trials (n < 40) conducted primarily in patients with relapsed or refractory B-cell CLL, rituximab monotherapy (various regimens) achieved OR rates of 23-45%, with median duration of response ranging from approximately 3-10 months. (ABSTRACT TRUNCATED)

Immunotherapy with anti-CD20 compounds

The B-cell surface antigen CD20 is currently the prime target for near-selective treatment of mature B-cell malignancies and a range of reactive B-cell associated disorders (including virus-associated lymphoproliferation or autoimmune conditions). CD20 is strongly and homogeneously expressed on the majority of mature B-cell neoplasms except chronic lymphocytic leukaemia cells, and on all mature reactive B-cells. This review will summarise the modes of action of various reagents targeting CD20. Treatment results following their use in single and combination therapy for B-cell disorders are reviewed.

Antibody therapy of non-Hodgkin's B-cell lymphoma

Engineering antibodies with reduced immunogenicity and enhanced effector functions, and selecting antigen targets with the appropriate specificity, density, and/or functionality, have contributed to the recent clinical successes in using unconjugated "naked" antibody therapies of B-cell lymphoma (rituximab) and breast carcinoma (Herceptin). The non-overlapping toxicities of naked antibodies and chemotherapy, together with their potential synergy, which is based on unique and complementary mechanisms of action, have contributed to the creation of new standards of care in cancer therapy and management. Clinical trial results supporting these concepts are presented. Furthermore, the exquisite specificity of antibodies renders them ideal vehicles for selective delivery of toxic payloads such as drugs or radionuclides. Although successful in therapy of hematological cancers (Zevalin, Mylotarg), the broader application of these technologies to carcinomas still remains to be proven in clinical testing. Engineering of antibody constructs with optimal blood clearance and tumor-targeting kinetics, and selecting the radionuclide that may deliver sufficient radiation energy to kill the more radio-resistant carcinomas, are discussed. With the advent of genomics and proteomics, new membrane-associated tumor antigens are being discovered and will provide novel targets for future antibody therapy of cancer.

Fractionated cyclophosphamide, vincristine, liposomal daunorubicin, and dexamethasone plus rituximab and granulocyte-macrophage-colony stimulating factor (GM-CSF) alternating with methotrexate and cytarabine plus rituximab and GM-CSF in patients with Richter syndrome or fludarabine-refractory chronic lymphocytic leukemia

BACKGROUND

Therapy for patients with Richter syndrome (RS) or fludarabine-refractory chronic lymphocytic leukemia (CLL) is unsatisfactory. A Phase II study was conducted to evaluate an alternating combination cytotoxic regimen given with rituximab and granulocyte-macrophage-colony stimulating factor (GM-CSF) in these patients.

METHODS

Fludarabine-refractory CLL was defined as failure to respond to most recent prior fludarabine-containing regimen. Patients received up to six cycles of fractionated cyclophosphamide, vincristine, liposomal daunorubicin, and dexamethasone (hyper-CVXD) plus rituximab and GM-CSF alternating with methotrexate and cytarabine plus rituximab and GM-CSF. Response, toxicity, and survival data were compared with data from prior therapy with hyper-CVXD alone in this patient group.

RESULTS

Forty-nine patients with RS (n = 30 patients) or refractory CLL (n = 19 patients) were treated on study. Nine patients (18%) achieved a complete remission, and 11 patients achieved a partial remission (22%), for an overall objective response (OR) rate of 41%. With a median follow-up of 7.5 months and a maximum follow-up of 15.2 months, the 12-month failure free survival (FFS) rate was 27%, and the overall survival (OS) rate was 39%. Nine patients (18%) died during the first cycle of therapy, and two patients (4%) died during the second cycle. There were no significant differences between the rates of OR, OS, and FFS in the current study and those obtained with hyper-CVXD alone on a prior study.

CONCLUSIONS

The study regimen had activity and significant toxicity in patients with RS or fludarabine-refractory CLL. It was not clearly better compared with hyper-CVXD alone in this patient population.

An overview of the current clinical use of the anti-CD20 monoclonal antibody rituximab

The chimeric anti-CD20 monoclonal antibody rituximab has become part of the standard therapy for patients with non-Hodgkin's lymphoma (NHL). To date, more than 300 000 patients have been treated with rituximab worldwide, including patients with indolent and aggressive NHL, Hodgkin's disease and other B-cell malignancies. Combination of rituximab with cytotoxic agents or cytokines has been explored in a number of different studies. Rituximab is now also approved for patients with diffuse large B-cell lymphoma when combined with standard CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone). The monoclonal antibody is generally well tolerated. Most adverse events are infusion-associated, including chills, fever and rigor related to the release of cytokines.