Rituximab long-term maintenance therapy after autologous stem cell transplantation in patients with B-cell non-Hodgkin’s lymphoma

Autologous hematopoietic cell transplantation: an update for clinicians

High-dose chemotherapy followed by transplantation of autologous hematopoietic progenitor cells has a proven track record of safety and efficacy in hematological malignancies and select solid tumors. The near-universal use of peripheral blood stem cells as source for autografts, routine growth factor support, and antimicrobial prophylaxis post transplantation has improved the safety of this procedure. However, the advent of highly active novel therapies in the last few years warrants reappraisal of the role of autologous transplantation in the therapeutic armamentarium of malignant disorder. This review summarizes the current role of autologous transplantation for hematological malignancies, discusses modern standards for patient selection, and highlights long-term care issues of transplant survivors from an internist's perspective. Role of tumor purging in autologous transplantation, novel transplant conditioning regimens, and post-transplant therapies to prevent disease relapse are reviewed.

Postulated mechanisms of resistance of B-cell non-Hodgkin lymphoma to rituximab treatment regimens: strategies to overcome resistance

Antibody-mediated immunotherapy has gained significant momentum since 1997 when the US Food and Drug Administration approved the first monoclonal antibody (mAb) for the treatment of B-cell non-Hodgkin lymphoma (B-NHL), namely, rituximab (chimeric anti-CD20 mAb). Subsequently, more than 20 approved mAbs have been in use clinically for the treatment of various cancers and several non-cancer-related diseases. Further, the combination treatment of mAbs with chemotherapy, immunotherapy, proteaosome inhibitors, and other inhibitors has resulted in synergistic anti-tumor activity with significant objective clinical responses. Despite their successful clinical use, the underlying mechanisms of rituximab's in vivo activities remain elusive. Further, it is not clear why a subset of patients is initially unresponsive and many responding patients become refractory and resistant to further treatments; hence, the underlying mechanisms of resistance are not known, Attempts have been made to develop model systems to investigate resistance to mAb therapy with the hope to apply the findings in both the generation of new therapeutics and in their use as new prognostic biomarkers. This review focuses on the development of resistance to rituximab treatments and discusses possible underlying mechanisms of action, postulated mechanisms of resistance in model systems, and suggested means to overcome resistance. Several prior reviews on the subject of rituximab resistance have been published and the present review both complements as well as adds new topics of relevance.

Incidence of hypogammaglobulinemia in patients receiving rituximab and the use of intravenous immunoglobulin for recurrent infections

Rituximab targets normal B cells and tumor B cells. We used a unique data-mining tool to identify patients with lymphoma who were treated with rituximab and who had serial pre and post rituximab immunoglobulin concentrations evaluated. After treatment, 39% (69/179) of patients had low levels of immunoglobulin G. Recurrent sinopulmonary infections were seen in 6.6% (14/211). Intravenous immune globulin appeared to reduce the frequency of infection.

BACKGROUND

Rituximab has altered the treatment approach to B-cell malignancies and other diseases. Reports consider that rituximab had limited impact on serum immunoglobulins. However, anecdotes suggest that rituximab can cause symptomatic hypogammaglobulinemia. This retrospective study examined the relationship among rituximab, hypogammaglobulinemia, and treatment of symptomatic hypogammaglobulinemia with intravenous immune globulin (IVIG).

METHODS

Patients with serial quantitative serum immunoglobulin (SIgG) concentrations before and subsequent to rituximab administration at Memorial Sloan-Kettering Cancer Center were identified. Information regarding rituximab administration, SIgG concentrations, frequency of infection, and administration of IVIG were recorded.

RESULTS

Between December 1998 and April 2009, 211 patients with B-cell lymphoma treated with rituximab and with serial SIgG concentrations were identified. One hundred seventy-nine (85%) patients had normal SIgG before rituximab, 32 (15%) had low SIgG. After rituximab use, hypogammaglobulinemia was identified in 38.54% of patients with initially normal SIgG. The risk was greater in patients who received maintenance rituximab. Symptomatic hypogammaglobulinemia that prompted IVIG administration developed in 6.6% of patients.

CONCLUSIONS

In this data set, rituximab administration was associated with a high frequency of hypogammaglobulinemia, particularly symptomatic hypogammaglobulinemia, among patients who received multiple courses of rituximab. Baseline and periodic monitoring of SIgGs is appropriate in patients who receive rituximab.

Increased infection rate after preemptive rituximab treatment for Epstein-Barr virus reactivation after allogeneic hematopoietic stem-cell transplantation

BACKGROUND

Preemptive rituximab (R) treatment decreases the incidence of Epstein-Barr virus (EBV) posttransplantation lymphoproliferative disease, but the extent of immune deficiency related to R in patients who received allogeneic hematopoietic stem-cell transplantation is unclear. The aim of our study was to evaluate the incidence of late infections and immune reconstitution after preemptive R treatment of EBV infection.

METHODS

Seventy-eight patients receiving preemptive R between January 2005 and January 2010 were studied. Fifty-two of them could be matched with controls (not receiving R) according to administration of antithymoglobulin, stem-cell source and donor type, age and grade of acute graft-versus-host disease.

RESULTS

Among the 78 patients with EBV reactivation treated with R, the 36-month cumulative incidence of bacterial, viral, and fungal infections was 64%, 59%, and 23%, respectively. When compared with controls, bacterial infection incidence was significantly higher in R patients (55% vs. 35%), and a slower reconstitution of B cells was observed. R patients had modest but not significantly higher nonrelapse mortality (35% vs. 15%) than controls.

CONCLUSION

R has dramatically decreased risks of posttransplantation lymphoproliferative disease but is followed by a prolonged and profound B-cell deficiency associated with an excess risk of bacterial infection and higher mortality. R should be given with caution, and immunoglobulin replacement should be provided to limit these excess risks.

Rituximab maintenance versus retreatment in follicular lymphoma

Follicular lymphoma (FL) is the most common type of indolent non-Hodgkin lymphoma. Although the introduction of the anti-CD20 monoclonal antibody rituximab has represented a major breakthrough, FL remains incurable with standard chemoimmunotherapies. The goals of therapy in symptomatic FL patients include the following: obtaining high response rates, extending the duration of remission, prolongation of survival and improving quality of life, while minimizing adverse events. To extend remission duration and possibly survival outcomes, maintenance therapy with rituximab has been shown to be effective in both frontline and relapsed/refractory settings. However, the optimal timing, schedule and length of maintenance therapy are controversial. Herein, we review the current data for maintenance rituximab in FL, discuss the current controversies for this modality, attempt to define its role relative to the more conservative retreatment approach and provide practical recommendations for its clinical use.

Rituximab resistance

Rituximab has become a ubiquitous component of treatment regimens for follicular non-Hodgkin lymphoma. Despite widespread clinical use, the mechanisms by which tumor cells resist rituximab-mediated destruction remain unclear. Rituximab relies in part on immune effector mechanisms for its antitumor effect, and thus resistance may be mediated not only by intrinsic tumor-cell alterations but also by the host immunological environment. In this article, we explore the mechanisms of action of rituximab, the incidence of rituximab resistance, and potential mechanisms of resistance. Finally, we discuss novel approaches to modulate the antibody, the tumor cell, and the host immunologic environment to overcome rituximab resistance. Further research into the mechanisms of rituximab resistance will be essential to improving the efficacy of anti-CD20 therapy in NHL, and may also pay dividends in the optimization of monoclonal antibody therapy across a wide range of diseases.

Phase II study of immunomodulation with granulocyte-macrophage colony-stimulating factor, interleukin-2, and rituximab following autologous stem cell transplant in patients with relapsed or refractory lymphomas

High-dose chemotherapy followed by autologous stem cell transplant (ASCT) leads to durable remissions in approximately half of patients with chemosensitive relapsed or refractory aggressive lymphomas; however, many will relapse despite ASCT secondary to persistent minimal residual disease (MRD) or malignant graft contamination. Post-transplant rituximab may eradicate MRD. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) might enhance the efficacy of rituximab by augmenting antibody-dependent cellular cytotoxicity (ADCC). We hypothesized that given together, rituximab, GM-CSF, and IL-2 might eradicate MRD and improve event-free survival following ASCT. Forty-six patients with relapsed non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma (HL) were enrolled. Stem cells were mobilized with G-CSF and GM-CSF following chemotherapy. Following BEAM conditioning, patients received GM-CSF until neutrophil engraftment. Between days + 30 and + 120, patients received one dose of rituximab 375 mg/m(2) (cycle 1), followed by three cycles of GM-CSF 250 microg/m(2)/day SQ days 1-5, IL-2 1.5 x 10(6) IU/m(2)/day SQ days 6-12, and rituximab 375 mg/m(2) IV day 9, repeated every 21 days. Thirty-eight patients were eligible for post-ASCT immunotherapy. Nine patients completed 1-2 cycles and 21 completed 3-4 cycles; eight patients did not receive post-ASCT immunotherapy. Grade 3-4 neutropenia and grade 3 thrombocytopenia were observed. With a median follow-up of 30 months, the estimated 5-year OS and EFS for all patients eligible for immunotherapy are 65% and 45%, respectively. Post-ASCT immunomodulation with rituximab, IL-2, and GM-CSF was feasible and safe, but not all patients were able to continue on to post-ASCT immunotherapy.

The role of rituximab in autologous and allogeneic hematopoietic stem cell transplantation for non-Hodgkin's lymphoma

The addition of rituximab to chemotherapy has substantially changed the treatment strategies for patients with B-cell lymphomas. Rituximab, combined with standard chemotherapy regimens, shows consistently improved results compared with chemotherapy alone and has been extensively employed in both newly diagnosed and relapsed patients with B-cell lymphoma. Because of its low toxicity profile and its potent antilymphoma activity mediated through direct apoptotic and indirect effector mechanisms, rituximab also has been actively incorporated into stem cell transplantation (SCT) protocols to attain a state of minimal disease, provide a safe and effective method for in vivo purging prior to autologous SCT, and promote graft-versus-lymphoma effects in allogeneic SCT. This review compiles the still immature but rapidly growing data on this combined modality.

Rituximab in the treatment of B-cell non-Hodgkin lymphoma, focus on outcomes and comparative effectiveness

Rituximab is an important and well established component in the treatment of many patients with B-cell non-Hodgkin lymphoma. In this paper we review recent clinical trials investigating the addition of rituximab to standard chemotherapy regimens for treatment of patients with diffuse large B cell lymphoma and follicular lymphoma. This report focuses upon treatment efficacy, quality of life, and safety of rituximab or rituximab-containing regimens. More uniquely, we review economic aspects of lymphoma treatments, including the cost of standard chemotherapy regimens with or without rituximab, cost effectiveness of rituximab in both induction and maintenance treatment, and lymphoma's impacts on patient's productivity and their caregivers. We conclude that adding rituximab to standard chemotherapy treatment for patients with B-cell non-Hodgkin lymphoma is safe and cost-effective in numerous settings during both induction and maintenance therapies. Despite extensive review of the literature, many important questions have yet to be answered in the rituximab era and these represent important directions for future study.

Optimal application of antibodies in the treatment of follicular lymphoma: current standards and future strategies

Advanced-stage follicular lymphoma has previously been described as an incurable disease. However, the introduction of monoclonal antibodies such as rituximab has considerably changed the management of the disease in the last decade with a significant subset of patients remaining in remission for a decade or longer. Rituximab, a CD20-targeting antibody, is approved for treatment both upfront and in the relapse setting. The most dramatic impact of this antibody is observed in combinations with conventional chemotherapy regimens. Encouraging results have also been reported from radiolabeled anti-CD20 antibodies. High response rates and durable remissions have been seen with both 90Y-ibritumomab tiuxetan and 131I-tositumomab. However, refractoriness to immunochemotherapy still remains a problem, especially in relapsed disease. Several novel targeted agents show encouraging activity in follicular lymphoma. This review will focus on current treatment strategies in this disease.

The late adverse events of rituximab therapy--rare but there!

Rituximab, an anti CD20 monoclonal antibody, has now become a cornerstone in the treatment of many CD20 positive hematological malignancies and a variety of autoimmune disorders. In contrast to the acute allergic and cytokine associated reactions, late adverse events of rituximab are indeed uncommon but at the same time probably under-reported. In this review, we detail late adverse events reported since its use in hemato-oncological neoplasias and other disorders. These adverse events include the development of late-onset neutropenia, defects of immune reconstitution with associated immune compromise, infections, progressive multifocal leukoencephalopathy, reactivation of hepatitis, intestinal perforation and interstitial pneumonitis. Possible mechanisms involved in rituximab-associated complications and the pathogenesis of these adverse effects are reviewed and discussed. Evidence based graded recommendations for the management of these adverse effects are proposed.

Commercial LightCycler-based quantitative real-time PCR compared to nested PCR for monitoring of Bcl-2/IgH rearrangement in patients with follicular lymphoma

Translocation of chromosomes 14 and 18 [t(14;18)] for detection of minimal residual disease in follicular lymphoma patients can be analyzed by nested polymerase chain reaction (PCR) or by quantitative PCR like LightCycler-based assays. We have compared both methods in blood and bone marrow samples of 28 patients enrolled in a clinical study on immunochemotherapy. In 42% of samples, the bcl2-IgH rearrangement was detectable by nested PCR, but not by LightCycler PCR. Nested PCR was able to reveal a significant drop in positive bone marrow or peripheral blood samples after therapy. In contrast, with LightCycler PCR, the detected drop in t(14;18)-positive cells did not reach statistical significance. The majority of patients showed positive results with nested PCR of peripheral blood or bone marrow without any associations to presence or absence of histological bone marrow (BM) infiltration by lymphoma cells. With LightCycler PCR, the numbers of positive cells were higher in samples from patients with BM infiltration of lymphoma cells (1.9 x 10(-2)) compared to samples from patients without involvement (4.08 x 10(-5)). A similar trend was seen in samples derived from the peripheral blood. Positivity for t(14;18) after therapy in two patients correlated with clinical relapse 6 months later. The data shown here demonstrate a lower sensitivity of LightCycler vs. nested PCR for detection of t(14;18). The usefulness of nested PCR for t(14;18) for risk stratification after primary therapy has to be validated in larger trials.

Rituximab therapy in malignant lymphoma

Rituximab is the first monoclonal antibody to have been registered for the treatment of B-cell lymphomas. Randomized studies have demonstrated its activity in follicular lymphoma (FL), mantle cell lymphoma and diffuse large B-cell lymphoma (DLBCL) in untreated or relapsing patients. Non-comparative studies have shown an activity in all other lymphomas. Because of its high activity and low toxicity ratio, rituximab has transformed the outcome of patients with B-cell lymphoma. A combination of rituximab plus chemotherapy, rituximab+cyclophosphamide+doxorubicin+vincristine+prednisolone (R-CHOP), has the highest efficacy ever described with any chemotherapy in DLBCL and FL. Some patients are refractory to rituximab but the precise mechanisms of this refractoriness are not understood.

Rituximab and its role as maintenance therapy in non-Hodgkin lymphoma

Since rituximab, a chimeric monoclonal anti-CD20 antibody, was introduced into clinical practice in 1997, data regarding its benefit in terms of response rate, quality of response, progression-free survival and overall survival in B-cell lymphoid malignancies continues to expand. Rituximab has proven to be a relatively well-tolerated drug, with its major side effects being infusion related. Rituximab was approved initially by the US FDA and the European Medicines Agency for relapsed or refractory low-grade or follicular CD20+ B-cell non-Hodgkin lymphomas. Subsequently, its use has been extended to include first-line therapy in low-grade lymphoma as well as the treatment of more aggressive histological subtypes such as diffuse large B-cell lymphoma. In this article, we review the landmark trials that have impacted clinical practice in follicular and diffuse large B-cell lymphomas and the emerging data for use of rituximab as maintenance therapy in non-Hodgkin lymphoma.

High incidence of non-neutropenic infections induced by rituximab plus fludarabine and associated with hypogammaglobulinemia: a frequently unrecognized and easily treatable complication

BACKGROUND

Rituximab is associated with low incidence of hypogammaglobulinemia and little morbidity. Our experience with the combination of rituximab + chemotherapy suggested the opposite.

PATIENTS AND METHODS

We analyzed our experience with rituximab plus chemotherapy in 97 patients to determine: frequency and type of non-neutropenic infection (NNI); frequency and type of hypogammaglobulinemia; response to gammaglobulin therapy; and factors associated with NNI.

RESULTS

We observed 40 episodes of NNI in 19 of 97 (20%) patients. By 3 years, 43% of patients treated with rituximab + chemotherapy were projected to have developed at least one NNI. Of 19 with NNI, 15 had Ig levels studied and all 15 had hypogammaglobulinemia. Most frequently affected Ig were IgG (14 of 15) and IgM (13 of 14). IgA was usually spared (six of 14 cases affected). NNIs observed were 18 bronchitis, 16 sinusitis, four pneumonias, three otitis media, two fevers of unknown origin (FUOs) and three herpes zoster. Hospitalization was required in seven of 19. Ten received gammaglobulin infusions and all responded promptly. Gammaglobulin was given only when NNIs recurred. We examined sex, age, histology, type of rituximab-chemotherapy (fludarabine + rituximab versus other chemotherapy + rituximab) for correlation with NNI.

CONCLUSIONS

Indolent histology, female sex and fludarabine + rituximab significantly correlated with frequency of NNI but multivariate analysis picked fludarabine + rituximab followed by female gender as the only two independent variables predictive of NNI.