Initial trials of anti-CD80 monoclonal antibody (Galiximab) therapy for patients with relapsed or refractory follicular lymphoma

Galiximab (anti-CD80)-induced growth inhibition and prolongation of survival in vivo of B-NHL tumor xenografts and potentiation by the combination with fludarabine

Galiximab is a primatized monoclonal antibody that targets CD80 expressed on malignant B cells and is being studied in the clinic as a potential treatment for follicular NHL. We have recently reported that galiximab signals B-NHL cells in vitro and inhibits cell growth and sensitizes resistant tumor cells to apoptosis by chemotherapeutic drugs. This study was designed to validate the in vitro findings in in vivo in mice. Thus, we examined in vivo the antitumor activity of galiximab used alone and in combination with chemotherapeutic agents in SCID mice bearing human lymphoma xenografts. The in vivo antitumor effects of galiximab used alone and in combination with fludarabine or doxorubicin were determined in solid and disseminated human B-lymphoma tumors grown in SCID mice. Galiximab monotherapy in vivo demonstrated significant antitumor activity in a Raji lymphoma solid tumor model and in an SKW disseminated lymphoma tumor model. There was significant inhibition in tumor growth and prolongation of survival. In vitro, galiximab sensitized Raji cells to apoptosis by both fludarabine and doxorubicin. Tumor growth inhibition was significantly enhanced when the mice were treated with the combination of galiximab and fludarabine. These findings support the potential clinical application of galiximab in combination with chemotherapeutic drugs for the treatment of CD80-expressing hematological malignancies.

The role of B7 family molecules in hematologic malignancy

The B7 family consists of structurally related, cell-surface proteins that regulate immune responses by delivering costimulatory or coinhibitory signals through their ligands. Eight family members have been identified to date including CD80 (B7-1), CD86 (B7-2), CD274 (programmed cell death-1 ligand [PD-L1]), CD273 (programmed cell death-2 ligand [PD-L2]), CD275 (inducible costimulator ligand [ICOS-L]), CD276 (B7-H3), B7-H4, and B7-H6. B7 ligands are expressed on both lymphoid and nonlymphoid tissues. The importance of the B7 family in regulating immune responses is clear from their demonstrated role in the development of immunodeficiency and autoimmune diseases. Manipulation of the signals delivered by B7 ligands shows great potential in the treatment of cancers including leukemias and lymphomas and in regulating allogeneic T-cell responses after stem cell transplantation.

Novel antibodies against follicular non-Hodgkin's lymphoma

The anti-CD20 monoclonal antibody rituximab has revolutionized the treatment of patients with follicular B-cell lymphoma. With the combination of chemotherapy and rituximab the overall survival rate has increased with approximately 30%. Unfortunately, there is resistance to rituximab with relapse of the disease in about 60% of the patients during the first five years of treatment and eventually in all patients. To this end, there is a need to develop improved anti-CD20 monoclonal antibodies and antibodies that target other attractive molecules expressed on the follicular lymphoma cell. This review describes the development and clinical achievements so far of next generation anti-CD20 and other antibodies in the treatment of follicular B-cell lymphoma.

Monoclonal antibodies for non-Hodgkin's lymphoma: state of the art and perspectives

Monoclonal antibodies have been the most successful therapeutics ever brought to cancer treatment by immune technologies. The use of monoclonal antibodies in B-cell Non-Hodgkin's lymphomas (NHL) represents the greatest example of these advances, as the introduction of the anti-CD20 antibody rituximab has had a dramatic impact on how we treat this group of diseases today. Despite this success, several questions about how to optimize the use of monoclonal antibodies in NHL remain open. The best administration schedules, as well as the optimal duration of rituximab treatment, have yet to be determined. A deeper knowledge of the mechanisms underlying resistance to rituximab is also necessary in order to improve the activity of this and of similar therapeutics. Finally, new antibodies and biological agents are entering the scene and their advantages over rituximab will have to be assessed. We will discuss these issues and present an overview of the most significant clinical studies with monoclonal antibodies for NHL treatment carried out to date.

Galiximab: a review

IMPORTANCE OF THE FIELD

A significant number of patients relapse or do not respond to rituximab due to intrinsic or acquired resistance. Hence, mAbs targeting other cell surface antigens on B-cell lymphomas are being studied. CD80 is a glycoprotein expressed on Hodgkin's lymphoma, mature B-cell lymphomas and immunoeffector cells which may have T-regulatory, in addition to direct antitumor activity. CD80 serves as an attractive target in the continued development of mAbs against lymphoma.

AREAS COVERED IN THIS REVIEW

Preclinical studies with galiximab, an anti-CD80 primatized mAb, have been encouraging and have demonstrated antitumor activity against various B-cell lymphoma models, both as a single agent as well as in combination with rituximab. Data were reviewed from a PubMed literature search from 1975 to 2009 and also included a review of abstracts from published proceedings of annual meetings from the American Society of Hematology and International Conference of Malignant Lymphoma, Lugano.

WHAT THE READER WILL GAIN

Readers will gain a better understanding of mechanisms of action (both documented and proposed) of galiximab. An update of currently available clinical data will be presented.

TAKE HOME MESSAGE

Data from completed clinical trials are promising and galiximab is being studied in both upfront and relapsed settings with the potential of being incorporated into the future treatment of B-cell lymphoma.

Mantle cell lymphoma: state-of-the-art management and future perspective

Mantle cell lymphoma (MCL) is a unique subtype of B-cell non-Hodgkin lymphomas (NHL) characterized in almost all cases by the chromosomal translocation t(11;14)(q13;q32) and nuclear cyclin D1 overexpression. Most patients present with advanced stage disease, often with extranodal dissemination, and typically pursue an aggressive clinical course. Recent improvement has been achieved by the successful introduction of monoclonal antibodies and dose-intensified approaches including autologous stem cell transplantation strategies. However, with the exception of allogeneic hematopoietic stem cell transplantation, current treatment approaches are not curative and the corresponding survival curve is characterized by a relatively steep and continuous decline, with a median survival of about 4 years and <15% long-term survivors. Despite its rarity, MCL is of particular clinical and scientific interest by providing a paradigm for neoplasms with dysregulated control of cell cycle machinery and impaired apoptotic pathways. Recently gained insights into underlying pathobiology unravel numerous promising molecular targeting strategies, however their introduction into clinical practice and current treatment algorithms remains a challenge. This article will provide relevant information for decision making in clinical practice and give a perspective on upcoming management strategies.

Immunophenotypic identification of possible therapeutic targets in paediatric non-Hodgkin lymphomas: a children's oncology group report

Immunophenotypic analysis can identify protein epitopes in non-Hodgkin lymphomas (NHL) that may respond to targeted immunotherapies, such as anti-CD20 and anti-CD52. Recent studies suggest additional targets may provide therapeutic benefits in NHL. This study evaluated protein expression of CD25, CD52, CD74 and CD80 in paediatric NHL to determine possible targets for immune-based therapeutic approaches. Patient samples were derived from paediatric NHL clinical trials sponsored by the Children's Cancer Group (CCG, now the Children's Oncology Group, COG) and included Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), disseminated T- and B-cell lymphoblastic lymphoma (T-LBL and B-LBL) and anaplastic large cell (ALCL). Immunophenotypic studies were performed on formalin-fixed, paraffin-embedded diagnostic tissues. CD25 was expressed in 8% of T-LBL and 75% of ALCL cases, but not in BL, DLBCL, or B-LBL. CD52 was expressed in 99% of cases of paediatric NHL of all subtypes. CD74 was expressed in 100% of B-LBL, BL and DLBCL, but was absent in ALCL and T-LBL. CD80 was expressed in 12% of B-LBL, 6% of BL and 10% of DLBCL cases studied, but was not detected in T-cell NHL. These expression patterns suggest that CD25, CD52 and CD74 may represent potential new therapeutic targets in paediatric NHL.

A phase I/II study of galiximab (an anti-CD80 monoclonal antibody) in combination with rituximab for relapsed or refractory, follicular lymphoma

BACKGROUND

Galiximab is a monoclonal antibody that targets CD80, a costimulatory molecule constitutively expressed on follicular and other lymphomas. Modest single-agent clinical activity and tolerability were demonstrated in a phase I study in relapsed or refractory, follicular non-Hodgkin's lymphoma (NHL). A phase I/II study was conducted to evaluate galiximab in combination with a standard course of rituximab. Safety, pharmacokinetics, and efficacy were evaluated.

PATIENTS AND METHODS

Patients with follicular NHL who had relapsed or failed primary therapy were enrolled. Rituximab-refractory patients (no response or a response with time to progression <6 months) were excluded. Patients received 4 weekly i.v. infusions of galiximab (125, 250, 375, or 500 mg/m(2)) and rituximab (375 mg/m(2)). International Workshop Response Criteria (IWRC) were used to evaluate response.

RESULTS

Seventy-three patients received treatment. All had received at least one prior lymphoma therapy; 40% were rituximab naive. Infusions were delivered in an outpatient setting and were well tolerated. The most common study-related adverse events (AE) were lymphopenia, leukopenia, neutropenia, fatigue, and chills. The overall response rate at the recommended phase II dose of galiximab (500 mg/m(2)) was 66%: 19% complete response, 14% unconfirmed complete response, and 33% partial response. The median progression free survival was 12.1 months. Combination therapy did not appear to alter pharmacokinetics.

CONCLUSION

These results indicate that galiximab can be safely combined with a standard course of rituximab. This doublet biologic approach offers the potential to avoid or delay chemotherapy or to integrate with other lymphoma therapies. A phase III, randomized study evaluating clinical benefit of rituximab versus the combination has been initiated.

Targeting Lymphoma Cells and Their Microenvironment with Novel Antibodies

Novel monoclonal antibodies are currently being evaluated and have been shown to have significantly influenced the treatment of Hodgkin's and non-Hodgkin's lymphoma. It is of the utmost importance to reduce treatment-related toxicity and, hopefully, improve the cure rate of lymphoma. This is possible by using novel therapies such as monoclonal antibodies, which target tumor cells while sparing normal cells. Investigational antibody therapies include those targeting malignant cells as well as those targeting the microenvironment. Continued investigation is encouraged to combine monoclonal antibodies with other targeted therapies and incorporate their use into standards of care in the treatment of lymphoma.

Immunotherapy for non-Hodgkin's lymphoma: monoclonal antibodies and vaccines

Advances in the development of monoclonal antibodies have led to new agents rapidly incorporated into standard lymphoma therapy. The characteristics of the target antigen and the properties of the antibody including interaction with the host immune system have been found to correlate with outcome. Antibodies targeting the CD20 antigen on B cells have been most widely used, led by the chimeric antibody rituximab, now used in nearly all types of B-cell non-Hodgkin's lymphoma (NHL). New antibodies targeting CD20 with augmented complement or Fc receptor binding are now being evaluated and will eventually have to be compared with rituximab. Challenges to these new antibodies include the nearly universal use of rituximab early in NHL therapy, and its increasing use as maintenance therapy. It is not clear what the activity of these antibodies will be in rituximab-refractory patients. New antibodies targeting antigens such as CD40 and CD80 are also being tested alone and in combination with rituximab. Vaccine trials using patient-specific immunization with immunoglobulin idiotype (Ig-Id present on the surface of most B-cell NHL) isolated by molecular rescue or by cell hybridization techniques are also nearing completion. These approaches attempt to actively induce specific humoral or cellular immune responses to the Ig-Id by attaching the protein to a carrier protein and the use of an immunologic adjuvant such as granulocyte macrophage colony-stimulating factor. Prior rituximab appears to delay humoral responses to the idiotype but may still allow cellular responses. The incorporation of all these approaches into optimal NHL therapy remains a challenge.

Monoclonal antibodies and fusion proteins in medicine

Humanized antibodies and decoy receptors have been introduced in clinical practice to treat malignancies and systemic autoimmune disease because they ablate specific cells or disrupt pathogenic processes at distinct points. Reported clinical responses offer hope to treatment-resistant patients, particularly those with lymphomas and rheumatic diseases. Side effects from the use of biologic agents include lymphokine release syndrome, reactivation of tuberculosis, and immunosuppression. Further insights are needed regarding limitation of adverse effects, correct use in conjunction with existing drugs, and treatment of patients in whom resistance develops.

Monoclonal antibody therapy of B cell lymphoma

Studies in the early 1980s with anti-idiotype mAbs provided clinical proof that mAbs could be safe and effective antilymphoma agents; however, mAb therapy of lymphoma did not become practical until the chimaeric anti-CD20 mAb rituximab was developed. As a single agent, rituximab is well-tolerated and has clinical efficacy in select patient populations. A number of mechanisms of action have been identified that appear to contribute to the observed antilymphoma effects of mAb. Growing evidence suggests that multiple interacting mechanisms are likely to be involved. Anti-CD20-based radioimmunotherapy and combinations of mAb and chemotherapy are showing promise. mAbs that recognise other target antigens and immunotoxins have been evaluated clinically. It remains unclear whether these other mAbs provide value added beyond rituximab. Research geared towards understanding mAb mechanisms of action and the rational design of the next generation of mAb-based regimens will allow us to take full advantage of this exciting new mode of therapy.

Characterization of a new humanized anti-CD20 monoclonal antibody, IMMU-106, and Its use in combination with the humanized anti-CD22 antibody, epratuzumab, for the therapy of non-Hodgkin's lymphoma

PURPOSE

A new humanized anti-CD20 monoclonal antibody (MAb), IMMU-106, was evaluated to elucidate its action as an antilymphoma therapeutic, as a single agent, and in combination with the anti-CD22 MAb, epratuzumab.

EXPERIMENTAL DESIGN

Antiproliferative effects, apoptotic effects, and the ability of IMMU-106 to mediate complement-mediated cytotoxicity and antibody-dependent cellular cytotoxicity on a panel of non-Hodgkin's lymphoma (NHL) cell lines were compared with the chimeric anti-CD20 MAb, rituximab, and evaluated in light of the various levels of antigen expression by the cell lines. In vivo therapy studies were performed in SCID mice bearing disseminated Raji lymphoma.

RESULTS

The mechanisms of cytotoxicity of IMMU-106 were found to be similar to rituximab, and include direct apoptosis, antibody-dependent cellular cytotoxicity, and complement-mediated cytotoxicity. IMMU-106 was also found to be very similar to rituximab in terms of antigen-binding specificity, binding avidity, and dissociation constant. Treatment of Raji-bearing SCID mice with IMMU-106 yielded median survival increases of up to 4.2-fold compared with control mice. Survival in mice treated with IMMU-106 plus epratuzumab was compared with IMMU-106 treatment alone. Although the combined treatment did not improve median survival, an increased proportion of long-term survivors was observed. An enhanced antiproliferative effect was also observed in vitro in SU-DHL-6 cells when IMMU-106 was combined with epratuzumab. These findings are consistent with the up-regulation of CD22 expression observed after pretreatment of NHL cells in vitro with CD20 MAb (IMMU-106).

CONCLUSIONS

It is expected that in humans IMMU-106 should be at least as effective as rituximab and, due to its human framework construction, it may exhibit different pharmacokinetic, toxicity, and therapy profiles. In addition, it may be possible to enhance efficacy by combination therapy comprised of anti-CD20 and other B-cell lineage targeting MAbs, such as epratuzumab. The current results emphasize that in vitro as well as in vivo studies with many of the NHL cell lines were generally predictive of the known activity of anti-CD20 MAbs in NHL patients, as well as the enhanced efficacy of epratuzumab combined with rituximab observed in early clinical trials.

Antibody-targeted therapy: a paradigm of innovative treatment strategies in indolent and aggressive B-cell non-Hodgkin lymphoma

PURPOSE OF REVIEW

This review outlines the principles of treatment of indolent and aggressive B-cell lymphoma based on current knowledge on the classification of hematologic malignancies and the rationale to implement new antibody-targeted immunotherapeutic approaches.

RECENT FINDINGS

An update is provided on the use of antibody-targeted therapies in clinical trials, with emphasis on new, emerging strategies of immunotherapy in B-cell non-Hodgkin lymphoma.

SUMMARY

The success of immune-mediated therapies has encouraged studies on antibody-targeted therapy in B-cell non-Hodgkin lymphoma. Promising new approaches combine classical dose-intense chemotherapy with "tumor-specific" antibody targeting during several phases of the disease. The safety and efficacy of anti-CD20 in the treatment of indolent and aggressive B-cell non-Hodgkin lymphoma at any stage of disease, either as a single agent or as part of multimodality regimes, as an unconjugated antibody or as radioimmunoconjugate have changed dramatically our treatment strategies. Increasing insights into basic molecular biology and immunology of B-cell non-Hodgkin lymphoma may identify subgroups of patients categorized in current classification systems who may benefit from tailored approaches with new modality antibody-targeted therapy in near future.

Antiproliferative activity of a humanized anti-CD74 monoclonal antibody, hLL1, on B-cell malignancies

The humanized anti-CD74 monoclonal antibody (mAb) hLL1 is under evaluation as a therapeutic agent. The effects of hLL1-at times in comparison with the CD20 mAb rituximab-were assessed on non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) cell lines and in tumor-bearing SCID mice. In vitro, hLL1 caused growth inhibition and induction of apoptosis in B-cell lines when cross-linked with an antihuman immunoglobulin G (IgG) second antibody. The sensitivity profile of the cell lines was different for hLL1 and rituximab, and antiproliferative activity was augmented when the 2 mAbs were combined. Unlike rituximab, hLL1 did not induce antibody-dependent cellular cytotoxicity or complement-mediated cytotoxicity. In xenograft models of NHL and MM, treatment with hLL1 yielded significant survival benefits without cross-linking agents. Efficacy was greater in the MM model, in which median survival time was increased more than 4.5-fold. Thus, hLL1 has therapeutic potential as a naked mAb for B-cell malignancies because of high antigen expression on malignant cells, specifically MM, with limited expression on normal tissue, and because of its antiproliferative activity. Further, hLL1 may be a therapeutic candidate for rituximab-resistant disease because the 2 antibodies apparently act through distinct mechanisms and exhibit different expression and sensitivity profiles, and activity can be augmented when the mAbs are combined.

Emerging antibody-targeted therapy in leukemia and lymphoma: current concepts and clinical implications

The success of immune-mediated therapies has encouraged studies on passive and active immunotherapy in leukemia and lymphoma. This review outlines the impact of increasing insights from basic immunology studies on the potentiation of effective immune responses and the identification of new antigens as targets for antibody (Ab)-targeted therapies. The principles of treatment in leukemia and lymphoma based on current knowledge on the classification of hematologic malignancies are reviewed, and discussed in the context of a rationale to implement new Ab-targeted immunotherapeutic approaches. An update is provided on the use of Ab-targeted therapies in clinical trials with emphasis on new emerging strategies to further expand the successful field of immunotherapy in leukemia and lymphoma.