A new schedule of CHOP/rituximab plus granulocyte-macrophage colony-stimulating factor is an effective rescue for patients with aggressive lymphoma failing autologous stem cell transplantation

Rituximab after autologous stem cell transplantation enhances survival of B-cell lymphoma patients: a meta-analysis and systematic review

BACKGROUND

Numerous studies have demonstrated the efficacy of rituximab before autologous stem cell transplantation (ASCT) for the treatment of B-cell non-Hodgkin lymphoma, but the few studies on rituximab treatment after ASCT have not established conclusively the clinical benefits of this particular treatment regimen.

PATIENTS AND METHODS

We conducted a metaanalysis of 3 comparative studies encompassing 407 lymphoma patients treated with rituximab after ASCT.

RESULTS

Combined results revealed a significantly higher event-free survival (EFS) in the rituximab-treated (R+) group compared with the R- group (P = .003 at 1 year; P = .03 at 3 years; P = .001 at 4 years). Moreover, the R+ group also demonstrated higher overall survival (OS) and complete remission (CR) rates (P = .0006 and P < .0001, respectively, at 1 year) without a significant increase in adverse events.

CONCLUSIONS

According to the included articles, there were no differences in CR, overall response, 3-year EFS, or 3-year OS between rituximab-naïve patients and patients previously treated with rituximab before ASCT. Post-ASCT maintenance regimens including rituximab show increased EFS, OS, and CR.

Combination strategies to enhance antitumor ADCC

The clinical efficacy of monoclonal antibodies as cancer therapeutics is largely dependent upon their ability to target the tumor and induce a functional antitumor immune response. This two-step process of ADCC utilizes the response of innate immune cells to provide antitumor cytotoxicity triggered by the interaction of the Fc portion of the antibody with the Fc receptor on the immune cell. Immunotherapeutics that target NK cells, γδ T cells, macrophages and dendritic cells can, by augmenting the function of the immune response, enhance the antitumor activity of the antibodies. Advantages of such combination strategies include: the application to multiple existing antibodies (even across multiple diseases), the feasibility (from a regulatory perspective) of combining with previously approved agents and the assurance (to physicians and trial participants) that one of the ingredients - the antitumor antibody - has proven efficacy on its own. Here we discuss current strategies, including biologic rationale and clinical results, which enhance ADCC in the following ways: strategies that increase total target-monoclonal antibody-effector binding, strategies that trigger effector cell 'activating' signals and strategies that block effector cell 'inhibitory' signals.

Clinical uses of GM-CSF, a critical appraisal and update

The role of granulocyte-macrophage-colony-stimulating factor (GM-CSF) in the supportive care of cancer patients has been evaluated with promising results. More recently, GM-CSF has been added to regimens for the mobilization of hematopoietic progenitor cells. An expanding role for GM-CSF in regulating immune responses has been recognized based upon its activity on the development and maturation of antigen presenting cells and its capability for skewing the immune system toward Th1-type responses. GM-CSF has been shown to preferentially enhance both the numbers and activity of type 1 dendritic cells (DC1), the subsets of dendritic cells responsible for initiating cytotoxic immune responses. The increase in DC1 content and activity following local and systemic GM-CSF administration support a role for GM-CSF as an immune stimulant and vaccine adjuvant in cancer patients. GM-CSF has shown clinical activity as an immune stimulant in tumor cell and dendritic cell vaccines, and may increase antibody-dependent cellular cytotoxicity. The successful use of myeloid acting cytokines to enhance anti-tumor responses will likely require the utilization of GM-CSF in combination with cytotoxic or other targeted therapies.

Granulocyte-macrophage colony stimulating factor-induced immune priming of cyclophosphamide, doxorubicin, vincristine, and prednisone with rituximab chemoimmunotherapy in previously untreated patients with diffuse large B-cell lymphoma and mantle cell lymphoma

Granulocyte-macrophage colony stimulating factor (GM-CSF) has been shown to enhance CD20 antigen expression, augment antibody-dependent cell-mediated cytotoxicity, and stimulate immune cell proliferation. This may lead to an improved anti-tumor effect of rituximab while reducing the severity of chemotherapy-induced myelosuppression. We evaluated the safety and efficacy of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in sequential combination with GM-CSF priming and rituximab in previously untreated patients (n = 39) with diffuse-large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). CHOP was administered every 21 days on day 1, GM-CSF 250 μg/m(2)/day on days 9 through 15, and rituximab 375 mg/m(2) on day 15 of each cycle. The overall response rate was 87%, with complete response in 64%. At a median follow-up of 84.3 months, the overall and progression-free survival rates were 54% and 49%, respectively. The most common toxicity was myelosuppression. Sequential combination of CHOP with GM-CSF priming and rituximab was feasible and effective, warranting further evaluation.

Addition of GM-CSF to trastuzumab stabilises disease in trastuzumab-resistant HER2+ metastatic breast cancer patients

Background:

One of the proposed mechanisms of trastuzumab-induced regression of human epidermal growth factor receptor 2-positive (HER2+) tumours includes facilitation of antibody-dependent cell-mediated cytotoxicity (ADCC). Granulocyte-macrophage colony-stimulating factor (GM-CSF) mediates ADCC. We presented our pilot study of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant HER2+ metastatic breast cancer.

Methods:

Patients with HER2+ metastatic breast cancer that progressed after trastuzumab +/− chemotherapy were continued on trastuzumab 2 mg kg^–1 intravenous weekly and GM-CSF 250 μg m^–2 subcutaneous daily. Patients were assessed for response every 8 weeks. Treatment was continued until disease progression or intolerable toxicity.

Results:

Seventeen patients were evaluable (median age 48 years, range 27–75 years). The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens for metastatic disease was 2 (range 1–5). No objective disease response was observed, but five patients (29%) had stable disease for a median duration of 15.8 (range 10–53.9) weeks. The most common adverse event was rash at the injection site. No grade 4 or irreversible adverse event was seen.

Conclusion:

The addition of GM-CSF to trastuzumab alone had a modest clinical benefit and acceptable safety profile in heavily pretreated patients with trastuzumab-resistant HER2+ metastatic breast cancer.

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.

Effect of addition of rituximab to salvage chemotherapy on outcome of patients with diffuse large B-cell lymphoma relapsing after an autologous stem-cell transplantation

BACKGROUND

We have investigated if rituximab-based salvage regimens improve response rates and survival of patients with diffuse large B-cell lymphoma (DLBCL) relapsing after an autologous stem-cell transplantation (ASCT).

PATIENTS AND METHODS

We have retrospectively analyzed 82 patients with DLBCL who received salvage therapy for relapse or progression after ASCT. Patients were divided into two groups, according to whether rituximab-based salvage regimens were given (n = 42, 'R-' group) or not (n = 40, 'R+' group) after ASCT.

RESULTS

Patients in the R+ group had better complete remission (CR) (55% versus 21.4%, P = 0.006) and overall response (OR) (75% versus 40.4%, P = 0.001) rates, and better 3-year event-free survival (EFS) (37% versus 9%, P = 0.002) and overall survival (OS) (50% versus 20%, P = 0.005) than patients in the R- group. Patients retreated with rituximab had better CR (42.9% versus 21.4%, P = 0.032) and OR (66.7% versus 40.4%, P = 0.019) rates, and better OS (36.2% versus 20% at 3 years, P = 0.05) and EFS (36.2% versus 9% at 3 years, P = 0.05) than patients who received chemotherapy alone at relapse after ASCT.

CONCLUSIONS

The addition of rituximab to salvage chemotherapy improves response rates and EFS in patients with relapsed DLBCL after ASCT. These patients may benefit from rituximab retreatment, although larger prospective studies are needed to confirm these results.

Dexa-BEAM as salvage therapy in patients with primary refractory aggressive Non-Hodgkin lymphoma

Although aggressive NHL in relapse after remission can still be cured by second-line treatment followed by high-dose therapy and autologous stem cell transplantation, the long-term prognosis of patients who fail to obtain remission after first-line therapy remains extremely poor. We retrospectively evaluated a series of 29 consecutive patients with primary refractory high-grade NHL who were treated with Dexa-BEAM (DB) as uniform salvage therapy at a single institution. Twenty-nine patients with aggressive NHL primary refractory to CHOP or CHOP-like induction therapy with a median age of 47 (range, 22 - 64) years received 1 - 2 cycles of DB and were candidates for subsequent autologous stem cell (PBSC) mobilization and transplantation (PBSCT). Follow-up of all patients was updated in March 2004. Eight of 29 patients (28%) responded to one cycle of DB (1 complete/7 partial remissions); 2 of whom are alive after PBSCT (1 autologous/1 matched unrelated donor), 1 patient died after autologous PBSCT. Reasons for failure to proceed to high-dose therapy in spite of response to DB were recurrent progressive disease (n = 2), septicemia (n = 1), and allogeneic transplant-related mortality after mobilization failure to DB (n = 2). Twenty-one patients failed to respond to DB and died of progressive disease. Overall survival was 7% after 41 months. We conclude that Dexa-BEAM salvage therapy is not effective in patients with truly primary refractory high-grade NHL. The efficiency of rituximab combined with Dexa-BEAM or novel chemotherapeutic strategies needs to be established.

Use of rituximab in diffuse large B-cell lymphoma in the salvage setting

The addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy was a milestone in the development of front-line therapy for diffuse large B-cell lymphoma (DLBCL). R-CHOP and equivalent rituximab-containing anthracycline-based regimens are now widely accepted as the standard of care in this setting. However, the optimal treatment for patients with DLBCL relapsing or progressing after front-line therapy is not yet established. This review explores the role of rituximab in the treatment of DLBCL in the salvage setting, as monotherapy, in combination with chemotherapy or novel agents, and in the context of autologous stem cell transplantation (ASCT). Current evidence suggests that rituximab may improve outcomes in several ways: the higher response rates achieved with rituximab-based induction in the salvage setting optimize the number of patients who are able to proceed to high-dose therapy -ASCT; rituximab may improve outcomes following ASCT when used as post-transplantation consolidation/maintenance therapy; and addition of rituximab to salvage regimens may improve outcomes for patients ineligible for transplantation. However, patients refractory to or relapsing after first-line therapy (including rituximab-based regimens) still have a poor prognosis. In conclusion, rituximab in salvage therapy for DLBCL is effective and well tolerated. Ongoing studies will further clarify the optimal use of rituximab in the salvage setting.

Granulocyte-macrophage colony-stimulating factor potentiates rituximab in patients with relapsed follicular lymphoma: results of a phase II study

PURPOSE

We hypothesized that granulocyte-macrophage colony-stimulating factor (GM-CSF) could potentiate the clinical activity of rituximab given its individual and cooperative effects on Fc gamma RIIa- and Fc gamma RIIIa-expressing cells. A phase II clinical study combining GM-CSF and rituximab was initiated in patients with relapsed follicular lymphoma (FL) to determine the clinical and biologic responses, as well as safety of the combination.

PATIENTS AND METHODS

Thirty three patients with relapsed FL were treated with GM-CSF 5 microg/kg/d on days 1 to 8 and rituximab 375 mg/m(2) on day 5 of each 21-day cycle for four cycles. Clinical response and tolerability were examined according to international criteria. Biologic monitoring included evaluation of immune cells involved in rituximab activity.

RESULTS

Of 33 evaluated patients, a 70% overall response rate (complete response plus complete response unconfirmed, 45%) and a median progression-free survival (PFS) of 16.5 months were achieved. Outcome was influenced by the quality of response and the Follicular Lymphoma International Prognostic Index (FLIPI), where low- and intermediate-risk FLIPI groups were associated with significantly better PFS. After treatment there was a significant increase in granulocyte and monocyte counts. Examination of dendritic cell response showed an overall increase in plasmacytoid dendritic cells, especially in non-complete response patients, after treatment. Addition of GM-CSF did not impair tolerance to rituximab, and adverse events were rare and mild.

DISCUSSION

GM-CSF plus rituximab results in high response rates, along with a tolerable safety profile in patients with relapsed or progressive FL. The improved efficacy over rituximab monotherapy may be due to increases seen in monocyte, granulocyte, and dendritic cell populations.

Macrophage colony-stimulating factor enhances rituximab-dependent cellular cytotoxicity by monocytes

Recent studies suggest that monocytes are the dominant effectors by which rituximab induces cell death in B-cell lymphoma. Because macrophage colony-stimulating factor (M-CSF) can enhance the cytotoxicity of monocytes, the authors examined whether this growth factor can enhance their ability to kill lymphoma cells in vitro. Monocytes derived from a healthy volunteer were cultured for 48 h in the presence or absence of M-CSF. Monocytes stimul ated with M-CSF were significantly more cytotoxic to Daudi B-cell lymphomas than unstimulated monocytes. Flow cytometry revealed that M-CSF increased monocyte expression of Fcgamma receptors III and I by 1.6- and 1.5-fold, whereas the expression of Fcgamma receptor II remained unchanged. These results suggest that pretreatment with M-CSF can improve the therapeutic efficacy of rituximab against intractable CD20(+) lymphoma.

Cancer therapeutic antibodies come of age: targeting minimal residual disease

Ten years after the first clinical application of Rituximab, an anti-CD20 recombinant monoclonal antibody, immunotherapy has become common practice in oncology wards. Thanks to the great diversity of the immune system and the powerful methodology of genetic engineering, the pharmacologic potential of antibody-based therapy is far from exhaustion. The recent application of Trastuzumab, an antibody to a receptor tyrosine kinase, in adjuvant breast cancer therapy marks the beginning of a new phase in cancer treatment. Here we discuss molecular mechanisms of antibody-based therapy, the emerging ability to target minimal disease and the therapeutic potential of combining antibodies with other modalities.

B CELL IMMUNOBIOLOGY IN DISEASE: Evolving Concepts from the Clinic

The pathogenic roles of B cells in autoimmune diseases occur through several mechanistic pathways that include autoantibodies, immune complexes, dendritic and T cell activation, cytokine synthesis, chemokine-mediated functions, and ectopic neolymphogenesis. Each of these pathways participate to different degrees in autoimmune diseases. The use of B cell-targeted and B cell subset-targeted therapies in humans is illuminating the mechanisms at work in a variety of human autoimmune diseases. In this review, we highlight some of these recent findings that provide insights into both murine models of autoimmunity and human autoimmune diseases.