In vivo depletion of B cells using a combination of high-dose cytosine arabinoside/mitoxantrone and rituximab for autografting in patients with non-Hodgkin's lymphoma

R-High-CHOP/CHASER/LEED with autologous stem cell transplantation in newly diagnosed mantle cell lymphoma: JCOG0406 STUDY

Although induction immunochemotherapy including high‐dose cytarabine and rituximab followed by high‐dose chemotherapy (HDC) with autologous stem cell transplantation (ASCT) is recommended for younger patients (≤65 years old) with untreated mantle cell lymphoma (MCL), no standard induction and HDC regimen has been established. We conducted a phase II study of induction immunochemotherapy of R‐High‐CHOP/CHASER followed by HDC of LEED with ASCT in younger patients with untreated advanced MCL. Eligibility criteria included untreated MCL, stage II bulky to IV, and age 20‐65 years. Patients received 1 cycle of R‐High‐CHOP followed by 3 cycles of CHASER every 3 weeks. Peripheral blood stem cells (PBSC) were harvested during CHASER. LEED with ASCT was delivered to patients who responded to R‐High‐CHOP/CHASER. Primary endpoint was 2‐year progression‐free survival (PFS). From June 2008 to June 2012, 45 patients (median age 59 years; range 38‐65 years) were enrolled. PBSC were successfully harvested from 36 of 43 patients. Thirty‐five patients completed ASCT. Two‐year PFS was 77% (80% CI 68‐84), which met the primary endpoint. Five‐year PFS and overall survival were 52% (95% CI 34‐68%) and 71% (95% CI 51‐84%), respectively. Overall response and complete response rates after induction immunochemotherapy were 96% and 82%, respectively. The most common grade 4 toxicities were hematological. In younger patients with untreated MCL, R‐High‐CHOP/CHASER/LEED with ASCT showed high efficacy and acceptable toxicity, and it can now be considered a standard treatment option.

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.

Hematopoietic stem cell transplantation for the management of follicular lymphoma

Although much has been published on the application of autologous and allogeneic hematopoietic stem cell transplantation in patients with follicular lymphoma (FL), no uniform consensus exists among physicians on when to use this strategy. Three large randomized trials failed to show a survival benefit using autologous transplantation for FL patients in first complete remission. Similarly, many Phase II or registry-based studies have also failed to show a survival benefit with autologous transplantation in relapsed or refractory FL patients, although the progression-free survival seems to be prolonged in transplant recipients. Allogeneic stem cell transplantation can cure a subset of patients with FL, but high nonrelapse mortality and morbidity remain a concern. No consensus exists on what conditioning regimen should be used, or how the newer monoclonal antibodies should be incorporated into the transplant paradigm. Here we present a review of the role of autologous and allogeneic hematopoietic stem cell transplantation in patients with FL.

Immunologic recovery following autologous stem-cell transplantation with pre- and posttransplantation rituximab for low-grade or mantle cell lymphoma

BACKGROUND

Rituximab may improve transplant outcomes but may delay immunologic recovery.

PATIENTS AND METHODS

Seventy-seven patients with low-grade or mantle cell lymphoma received autologous stem-cell transplantation (ASCT) on a phase II study. Rituximab 375 mg/m(2) was administered 3 days before mobilization-dose cyclophosphamide, then weekly for four doses after count recovery from ASCT. Immune reconstitution was assessed.

RESULTS

Sixty percent of transplants occurred in first remission. Actuarial event-free survival (EFS) and overall survival (OS) were 60% and 73%, respectively, at 5 years, with 7.2-year median follow-up for OS in surviving patients. Median EFS was 8.3 years. Older age and transformed lymphomas were independently associated with inferior EFS, whereas day 60 lymphocyte counts did not predict EFS or late infections. Early and late transplant-related mortality was 1% and 8%, with secondary leukemia in two patients. B-cell counts recovered by 1-2 years; however, the median IgG level remained low at 2 years. Late-onset idiopathic neutropenia, generally inconsequential, was noted in 43%.

CONCLUSION

ASCT with rituximab can produce durable remissions on follow-up out to 10 years. Major infections do not appear to be significantly increased or to be predicted by immune monitoring.

Aberrant DNA methylation of the p57KIP2 gene is a sensitive biomarker for detecting minimal residual disease in diffuse large B cell lymphoma

The detection of minimal residual disease (MRD) in bone marrow is very important in the clinical management of malignant lymphoma. So far, the assessment of MRD in cases of diffuse large B cell lymphoma (DLBCL) has had some technical limitations, such as requiring patient-specific primers and complicated experimental steps. To resolve these problems, we applied a tumor-specific epigenetic alteration of the p57KIP2 gene as a biomarker for detecting MRD in DLBCL. The methylation of the p57KIP2 gene was analyzed in 63 cases of DLBCL by methylation-specific real-time quantitative PCR. Methylation of the p57KIP2 gene was detected in 53 (84.1%) of these 63 cases of DLBCL. We could detect one p57KIP2 gene-methylated cell among 10,000 unmethylated cells by the serial dilution experiment. This sensitivity is proved to be equivalent to that of detection of bcl2/IgH rearrangement by real-time quantitative PCR. This sensitivity could be converted to the detection of two methylated genomes per reaction. Using clinical material, the same results were confirmed. In this study, we established a convenient and universal method for detecting MRD in DLBCL. This technique is applicable for over 80% of patients with DLBCL. This could promote systemic MRD studies in the area of DLBCL.

Role of the molecular staging and response in the management of follicular lymphoma patients

Bcl-2/IgH rearrangement is the molecular hallmark of follicular lymphoma which is present in 70 - 90% of cases at diagnosis. The significance of the bcl-2 rearrangement at onset of disease and of its clearing after treatment (molecular response) is still controversial. The aims of the present analysis are: to evaluate the incidence of bcl-2 rearrangement in blood and marrow in a cohort of patients systematically investigated at diagnosis, to describe the correlation between bcl-2 and presenting features, to clarify the correlation of molecular response with outcome. Of 98 patients studied at initial staging for the presence of bcl-2 rearrangement, 64 (65%) showed bcl-2/IgH rearrangement in peripheral blood (PB) and/or bone marrow (BM) (58 at Major Breakpoint Region, MBR, and 6 at minor cluster region, mcr) while no bcl-2/IgH rearrangement was detected in the remaining 34 (35%) (germline status). No statistically significant differences were found between bcl-2 positive and bcl-2 negative cases as concerns presenting clinical features and response to first-line therapy. The median event-free survival, EFS, was not reached for the bcl-2 negative patients in PB and was 11 months for bcl-2 positive patients (statistically significant, P = 0.01) and, similarly, the median EFS was not reached for the bcl-2 negative patients in BM and was 11 months for bcl-2 positive patients (statistically significant, P = 0.04). Of the 64 bcl-2 positive cases, patients were analysed for molecular response (48 in BM and 40 in PB): 16 were molecular responders in BM and 20 were molecular responders in PB. The median EFS was 19 months for molecular responders in PB and 9 months for non-responders; 1-year-EFS was 68% (95% CI; 49 - 88), for responders in PB and 42% (95% CI; 22 - 61) for non-responders (P = 0.05). The median EFS was 11 months both for molecular responders and non-responders in BM; 1-year-EFS was 52% for responders in BM (CI; 30 - 73), and 43% (CI 33 - 71) for non-responders (P = 0.7). No clinical feature showed significant correlation with PB and BM molecular responses. This analysis shows that bcl-2 rearrangement in blood and bone marrow is frequently detected at staging, even in stage I disease. Absence of the bcl-2 rearrangement is related to a better EFS and the achievement of a molecular response in peripheral blood after therapy is associated with a better EFS.

Combination of active specific immunotherapy or adoptive antibody or lymphocyte immunotherapy with chemotherapy in the treatment of cancer

Successful treatment of cancer patients with a combination of monoclonal antibodies (mAb) and chemotherapeutic drugs has spawned various other forms of additional combination therapies, including vaccines or adoptive lymphocyte transfer combined with chemotherapeutics. These therapies were effective against established tumors in animal models and showed promising results in initial clinical trials in cancer patients, awaiting testing in larger randomized controlled studies. Although combination between immunotherapy and chemotherapy has long been viewed as incompatible as chemotherapy, especially in high doses meant to increase anti-tumor efficacy, has induced immunosuppression, various mechanisms may explain the reported synergistic effects of the two types of therapies. Thus direct effects of chemotherapy on tumor or host environment, such as induction of tumor cell death, elimination of regulatory T cells, and/or enhancement of tumor cell sensitivity to lysis by CTL may account for enhancement of immunotherapy by chemotherapy. Furthermore, induction of lymphopenia by chemotherapy has increased the efficacy of adoptive lymphocyte transfer in cancer patients. On the other hand, immunotherapy may directly modulate the tumor's sensitivity to chemotherapy. Thus, anti-tumor mAb can increase the sensitivity of tumor cells to chemotherapeutic drugs and patients treated first with immunotherapy followed by chemotherapy showed higher clinical response rates than patients that had received chemotherapy alone. In conclusion, combination of active specific immunotherapy or adoptive mAb or lymphocyte immunotherapy with chemotherapy has great potential for the treatment of cancer patients which needs to be confirmed in larger controlled and randomized Phase III trials.

Rituximab improves the efficacy of high-dose chemotherapy with autograft for high-risk follicular and diffuse large B-cell lymphoma: a multicenter Gruppo Italiano Terapie Innnovative nei linfomi survey

PURPOSE

To investigate the impact of adding rituximab to intensive chemotherapy with peripheral-blood progenitor cell (PBPC) autograft for high-risk diffuse large B-cell lymphoma (DLB-CL) and follicular lymphoma (FL).

PATIENTS AND METHODS

Data were collected from 10 centers associated with Gruppo Italiano Terapie Innnovative nei Linfomi for 522 patients with DLB-CL and 223 patients with FL (median age, 47 years) who received the original or a modified high-dose sequential (HDS) chemotherapy regimen. HDS was delivered to 396 patients without (R-) and to 349 patients with (R+) rituximab; 154 (39%) and 178 patients (51%) in the R- and R+ subsets, respectively, underwent HDS for relapsed/refractory disease.

RESULTS

A total of 355 R- (90%) and 309 R+ patients (88%) completed the final PBPC autograft. Early treatment-related mortality was 3.3% for R- and 2.8% for R+ (P = not significant). Two parameters significantly influenced the outcome: disease status at HDS, with 5-year overall survival (OS) projections of 69% versus 57% for diagnosis versus refractory/relapsed status, respectively, and rituximab addition, with 5-year OS of 69% versus 60% in the R+ versus R- groups, respectively. In the multivariate analysis, these two variables maintained an independent prognostic value. The marked benefit of rituximab was evident in patients receiving HDS as salvage treatment: the 5-year OS projections for R+ versus R- were, respectively, 64% versus 38%, for patients with refractory disease or early relapse and 71% versus 57%, for patients with late relapse, partial response, or second/third relapse.

CONCLUSION

The results of this large series indicate that rituximab should be included in the current practice of PBPC autograft for DLB-CL and FL.

Follicular lymphomas

Follicular lymphomas constitute approximately 30% of all non-Hodgkin lymphomas. These lymphomas are characterized by at least partially follicular growth pattern, but diffuse areas may be present. The proportions of follicular or diffuse areas vary also from case to case, which seems to be associated with prognosis. Follicular lymphomas should not be divided into distinct subtypes, but rather shows a continuous gradation in the number of large cells. On the bases of this grading, three groups have been defined: grades 1-3. There is a consensus that grade 3 follicular lymphomas, namely grade 3b, should be discriminated from lower-grade cases. The cells of follicular lymphomas express surface immunoglobulin, more frequently IgM+/-IgD>IgG>IgA, B-cell-associated antigens, CD10+/-; they are CD5-, CD23-/+, CD43-, and CD11c-. Follicular lymphomas express bcl-2 proteins, which is useful in distinguishing reactive from neoplastic follicles. t(14;18) is present in 70-95% of follicular lymphomas, involving rearrangement of bcl-2 gene. Clinical behavior of follicular lymphomas is heterogeneous and differs according to the histologic grade and extension of disease. Moreover, the evaluation of these malignancies is conditioned by therapeutic decision, which is also determined by main prognostic factors. The International Prognostic Index for aggressive lymphomas is not optimal for follicular lymphomas. Conversely, the Italian Lymphoma Intergroup Index and, more recently, the Follicular Lymphoma International Prognostic Index (FLIPI), designed in pre-rituximab era, seem to correlate well with outcome. Several active therapeutic approaches from the "wait and watch" strategy to the allogeneic transplantation are available for management of patients with follicular lymphoma. Therapeutic decision is mostly conditioned by patient's characteristics, stage, histologic grade, tumor burden, and risk-predicting factors.

Immunochemotherapy with in vivo purging and autotransplant induces long clinical and molecular remission in advanced relapsed and refractory follicular lymphoma

BACKGROUND

To evaluate the clinical outcome of patients with relapsed or refractory follicular lymphoma treated with immunochemotherapy, in vivo purging and high-dose therapy with autotransplant.

PATIENTS AND METHODS

Sixty-four patients were enrolled in the trial. Primary end point was progression-free survival (PFS). Secondary end points were the in vivo purging effect on stem-cell harvest and the impact of molecular response on the outcome.

RESULTS

At enrollment, 59% of patients were PCR+ for bcl-2 rearrangement in bone marrow (PCR-informative). After the immunochemotherapy, before mobilization, 97% obtained complete response or partial response and 87% of patients informative for bcl-2 were molecularly negative. Sixty-one patients proceeded to in vivo purging and peripheral blood stem cell (PBSC) mobilization with rituximab and high-dose AraC. The median number of CD34+ cells collected was 16.6 x 10(6)/kg. Of 33 PCR-informative patients, the harvests resulted in PCR- in all. Fifty-eight patients received high-dose therapy and autotransplant of in vivo purged PBSC. After a median follow-up of 3.5 years, 41 patients are in complete remission. Five-year PFS is 59%.

CONCLUSION

This study demonstrates that patients with advanced relapsed or refractory follicular lymphoma treated with immunochemotherapy, in vivo purging and autotransplant may obtain long-lasting PFS. In bcl-2-positive patients, in vivo purging allows the harvest of lymphoma-free PBSC. Absence of the bcl-2 rearrangement after autotransplant is associated with persistent clinical remission.

Mobilization of peripheral blood progenitor cells after DHAP regimen with or without rituximab: a large multicenter comparative study in patients with malignant lymphoma

DHAP regimen is commonly used in patients with lymphoma. It is routinely used in combination with the monoclonal anti-CD20 antibody rituximab (R-DHAP), particularly for peripheral blood stem cell (PBSC) mobilization. The aim of this study was to assess the impact of rituximab on PBSC mobilization in patients with lymphoma receiving DHAP chemotherapy. We retrospectively reviewed the data of patients treated by DHAP or R-DHAP regimens as PBSC mobilization protocol between July 1998 and June 2005. Sixty-nine patients were included in the study: 21 in the DHAP group and 48 in the R-DHAP group. Both groups were not statistically different in term of clinical and biological presentation of the disease. The first cytapheresis was performed at day 10 in the R-DHAP group versus day 11 in the DHAP group. In contrast, the number of circulating CD34(+) cells was higher, but not significant, in the R-DHAP group than the DHAP group, namely 9.7x10(6) CD34(+) cells/kg and 6.1x10(6) CD34(+) cells/kg, respectively. Finally, the complete remission status at time of harvest was the only one factor associated with poor mobilization on multivariate analysis. In conclusion, our results show that rituximab does not impair PBSC collection.

Hematopoietic cell transplantation: progress and obstacles

The use of hematopoietic cell transplantation has expanded and evolved substantially in the last decade. New stem cell sources and stem cell mobilizing agents have been introduced in clinical practice. The incidence of life-threatening complications following autologous stem cell transplant procedures has decreased dramatically. Understanding the immune mediated effect of allogeneic stem cell transplantation has resulted in the development of reduced intensity and non-myeloablative conditioning regimens, allowing transplantation of elderly patients. Long-term complications are starting to emerge, and will gain in importance in the near future.

Prolonged survival in poor-risk diffuse large B-cell lymphoma following front-line treatment with rituximab-supplemented, early-intensified chemotherapy with multiple autologous hematopoietic stem cell support: a multicenter study by GITIL (Gruppo Italiano Terapie Innovative nei Linfomi)

A prospective multicenter program was performed to evaluate the combination of rituximab and high-dose (hd) sequential chemotherapy delivered with multiple autologous peripheral blood progenitor cell (PBPC) support (R-HDS-maps regimen) in previously untreated patients with diffuse large B-cell lymphoma (DLB-CL) and age-adjusted International Prognostic Score (aaIPI) score 2-3. R-HDS-maps includes: (i) three APO courses; (ii) sequential administration of hd-cyclophosphamide (CY), hd-Ara-C, both supplemented with rituximab, hd-etoposide/cisplatin, PBPC harvests, following hd-CY and hd-Ara-C; (iii) hd-mitoxantrone (hd-Mito)/L-Pam + 2 further rituximab doses; (iv) involved-field radiotherapy. PBPC rescue was scheduled following Ara-C, etoposide/cisplatin and Mito/L-Pam. Between 1999 and 2004, 112 consecutive patients aged <65 years (74 score 2, 38 score 3) entered the study protocol. There were five early and two late toxic deaths. Overall 90 patients (80%) reached clinical remission (CR); at a median 48 months follow-up, 87 (78%) patients are alive, 82 (73%) in continuous CR, with 4 year overall survival (OS) and event-free survival (EFS) projections of 76% (CI 68-85%) and 73% (CI 64-81%), respectively. There were no significant differences in OS and EFS between subgroups with Germinal-Center and Activated B-cell phenotype. Thus, life expectancy of younger patients with aaIPI 2-3 DLB-CL is improved with the early administration of rituximab-supplemented intensive chemotherapy compared with the poor outcome following conventional chemotherapy.

High-dose rituximab does not negatively affect peripheral blood stem cell mobilization kinetics in patients with intermediate-grade non-Hodgkin's lymphoma

Rituximab, an anti-CD20 human-mouse chimeric monoclonal antibody has been shown to improve response rates when it is combined with standard salvage chemotherapy in patients with relapsed or refractory intermediate-grade B-cell non-Hodgkin's lymphoma. A vast majority of these patients subsequently undergo high-dose therapy followed by stem cell transplantation. However, the impact of rituximab on stem cell mobilization kinetics is not well characterized. The purpose of this study was to study the effect of high-dose rituximab given with chemotherapy on stem cell mobilization in patients with intermediate-grade B-cell non-Hodgkin's lymphoma. Thirty-six patients received ifosfamide, etoposide, and rituximab followed by filgrastim for stem cell mobilization. The chemotherapy regimen was well tolerated. Thirty-four of 36 patients (94%) were able to mobilize at least 2 x 10(6) CD34+ cells/kg body weight after a median of 2 apheresis procedures. The median CD34+ cell dose collected per kilogram of recipient body weight was 6.5 x 10(6) (range, 4.65-31.15). All patients who subsequently underwent high-dose chemotherapy and stem cell transplantation experienced sustained engraftment. In conclusion, high-dose rituximab given during stem cell mobilization does not negatively affect stem cell mobilization kinetics.

Long-Term Follow-Up of Patients with Non-Hodgkin Lymphoma Following Myeloablative Therapy and Autologous Transplantation of CD34+-Selected Peripheral Blood Progenitor Cells

Graft engineering by CD34(+) selection of peripheral blood progenitor cells (PBPC) has been used in non-Hodgkin lymphoma (NHL) with the aim to reduce relapse related to tumor cells within the graft. From September 1995 to January 2000, 39 patients with newly diagnosed (n = 31) or relapsed (n = 8) NHL were treated in our institution with myeloablative therapy followed by CD34(+) selected autologous PBPC transplantation. Thirty-one patients were diagnosed with follicular lymphoma, and eight patients with mantle-cell lymphoma. All patients had advanced disease (26% of patients stage III and 74% stage IV, Ann Arbor classification). Induction therapy resulted in a complete remission in 17 patients and a partial remission in 22 patients. PBPC were mobilized after cytotoxic chemotherapy with granulocyte colony-stimulating factor support. CD34(+) selection was performed using immunomagnetic beads (Baxter Isolex 300SA or 300i Magnetic Cell Separation System). Most patients (85%) received total body irradiation and high-dose cyclophosphamide as myeloablative regimen. Twelve patients also received rituximab 375 mg/m(2) before radiation and before the start of the cyclophosphamide treatment. The mean CD34(+) cell number for transplantation was 6.5 x 10(6) CD34(+) cells/kg of body weight. Platelet recovery (>20,000/microl median on day 13) and leukocyte recovery (>1,000/microl median on day 12) were within expected range. The estimated median follow-up was 47 months. The probabilities of freedom from progression, overall survival, and event-free survival 4 years after transplantation were 96%, 90%, and 87%, respectively, for patients with follicular lymphoma and 42%, 63%, and 33%, respectively, for patients with mantle-cell lymphoma. Risk factors for relapse were age and extranodal manifestation of disease. The rate of lethal infections in the 12-month follow-up period was 8%. We conclude that CD34(+) selection of autologous transplants following myeloablative therapy is feasible and results in long-term remission in the majority of patients, but the procedure is probably related to a higher rate of lethal infections.

Rituximab added to an intensified salvage chemotherapy program followed by autologous stem cell transplantation improved the outcome in relapsed and refractory aggressive non-Hodgkin lymphoma

We investigated the addition of rituximab to an intensified salvage program followed by a myeloablative course with autologous stem cell transplantation (ASCT) in patients with relapsed or refractory aggressive non-Hodgkin lymphoma (NHL). Patients with relapsed or progressive aggressive NHL were treated with two cycles of conventional salvage chemotherapy (DHAP) followed by high-dose sequential chemotherapy (cyclophosphamide, methotrexate with vincristine and etoposide) and a final myeloablative course (BEAM) with ASCT. Rituximab (375 mg/m(2)) was administered at each treatment cycle. This cohort was compared with a historical control group of patients treated with the same chemotherapy but without rituximab. Patients from both groups were matched by duration of first remission and lactate dehydrogenase serum levels. Forty-five patients were treated with chemotherapy and 22 with immunochemotherapy. The overall response rates (ORR) at the final evaluation were 63% for the immunochemotherapy group and 42% for the chemotherapy group (p = 0.330). In the historical controlled analysis freedom from second failure (FF2F) at 2 years in the immunochemotherapy group was 57% and overall survival (OS) was 77%. FF2F in the chemotherapy group was 18% (p = 0.0051) and OS was 37% (p = 0.0051). In the matched-pair analysis, FF2F was 58% in the immunochemotherapy group compared to 16% in the chemotherapy group (p = 0.0517); OS was 74 vs 33%, respectively (p = 0.0424). The toxicity was tolerable and comparable in both groups. The addition of rituximab to an intensified salvage chemotherapy regimen seems to improve the prognosis. However, only prospective randomized trial can offer sufficient data of the value of rituximab in relapsed and refractory aggressive NHL.

Effect of CD34 cell dose on hematopoietic reconstitution and outcome in 508 patients with multiple myeloma undergoing autologous peripheral blood stem cell transplantation

BACKGROUND

We analyzed the hematopoietic reconstitution and outcome of 508 patients with multiple myeloma (MM) with respect to the number of CD34+ cells reinfused at our center.

PATIENTS AND METHODS

Each cohort of 390 patients (unselected CD34+ cell transplant) and 118 patients (CD34+ selected transplant) was divided into four subgroups. Among the 390 transplantations, 86 patients received a high dose (HD-) of > or =6.50 x 10(6) unselected CD34+ cells/kg, 116 patients a low dose (LD-) of <3.00 x 10(6) CD34+ cells/kg. Among the patients treated with CD34+ selected PBSC, 34 received > or =6.50 x 10(6) CD34+ cells/kg (HD+) and 16 <3.00 x 10(6) CD34+ cells/kg (LD+).

RESULTS

HD- patients experienced a reduced median time to leukocyte (13 d vs. 14 d) (P < 0.001) and platelet reconstitution >20 x 10(9)/L (10 d vs. 12 d) (P < 0.001). Similarly, HD+ showed a reduced median time to leukocyte (12 d vs. 15 d) (P < 0.001) and platelet recovery >20 x 10(9)/L (10 d vs. 11 d) (P = 0.058). CD34+ cell-dose was significant for long-term platelet recovery at day 360 (unselected transplant P = 0.015, selected transplant P = 0.023). Number of transplanted CD34+ cells had no significant impact on transplant related mortality, overall survival or CR/PR rates within 100 d. In terms of supportive care the differences of high-/low-dose grafts were minimal.

CONCLUSIONS

These results confirm that high doses of CD34+ PBSC shorten hematopoietic reconstitution and reduce hospitalization. Nevertheless secure engraftment results from transplantation of 2.00-3.00 x 10(6) CD34+ cells/kg. As 60% of our pretreated patients are able to collect > or =5.00 x 10(6) CD34+ cells/kg within a single leukapheresis, division into two or more freezing bags allows safe tandem transplantation in the majority of MM patients.

Effect of rituximab on the long-term outcome after high-dose therapy for relapsed B-cell non-Hodgkin’s lymphoma

To better define the role of rituximab in salvage and high-dose therapy (HDT) for relapsed or refractory non-Hodgkin's lymphoma (NHL), patients treated before the implementation of rituximab in salvage and HDT (n = 57, control group) were compared with patients with rituximab included in this procedure (n = 36, study group). All patients had been antibody-naive at this point, and analyses were performed separately for 22 and 31 patients with aggressive, and 14 and 26 patients with indolent NHL, respectively. All patients received two courses of salvage therapy, predominantly dexamethasone, BCNU, etoposide, cytosine arabinoside, melphalan. Conditioning regimens included BCNU, etoposide, cytosine arabinoside, melphalan; BCNU, etoposide, cytosine arabinoside, cyclophosphamide or total body irradiation and cyclophosphamide, with rituximab added for patients in the study group. Despite the absence of differences in stem cell collection, haematopoietic recovery was delayed in patients with aggressive NHL treated in the study group: median days to absolute neutrophil count more than 0.5 x 10(9)/l, 11 vs 10 (p = 0.01), and platelets more than 20 x 10(9)/l, 14 vs 11 (p = 0.0005), with an increased requirement for platelet transfusions. No similar observations were made in indolent lymphoma patients. Remission rates were superior for patients with aggressive NHL in the study group. With a median follow-up of 7.25 and 4.5 years, this resulted in an improvement in OS at 4.5 years: 67 vs 45% (95% confidence interval, 47-87% vs 28-64%; p = 0.0468). For patients with indolent lymphoma, no comparable benefit was detectable. Our data support the use of rituximab in HDT for patients with aggressive NHL. For patients with indolent NHL, only longer follow-up and/or randomized trials may help to fully determine the impact of rituximab on the outcome after HDT.

Successful autologous peripheral blood stem cell transplantation with rituximab administration for pediatric diffuse large B-cell lymphoma

A 13-year-old boy with chemotherapy-resistant diffuse large B-cell lymphoma (DLBCL) was successfully treated with autologous peripheral blood stem cell transplantation (auto-PBSCT) with administration of rituximab. Previous reports indicate that auto-PBSCT without rituximab for adult chemotherapy-resistant DLBCL is only marginally successful. The addition of rituximab administration might have intensified anti-tumor activity before the transplant procedure and might have enhanced the in vivo purging of the auto-graft, resulting in a successful outcome in this case. Although a few adverse effects are linked to rituximab administration, such as prolonged neutropenia, hypogammaglobulinemia, and increased infectious complications, the regimen of rituximab with SCT appears to be effective against chemotherapy-resistant DLBCL.

LightCyclerR-based quantitative real-time PCR monitoring of patients with follicular lymphoma receiving rituximab in combination with conventional or high-dose cytotoxic chemotherapy

OBJECTIVES

Quantitative real-time polymerase chain reaction (qPCR) is a suitable method to measure residual disease in hematological malignancies. Our objective was to assess a LightCycler-based qPCR for t(14;18)(q32;q21)(IgH/bcl-2)-positive cells quantification in the context of clinical and morphopathological characteristics of patients with follicular lymphoma treated with rituximab (R) in combination with conventional or high-dose chemotherapy.

METHODS

A total of 270 bone marrow (BM) and peripheral blood (PB) samples collected from 52 patients with follicular lymphoma at diagnosis or at relapse before or sequentially during therapy were examined by qPCR and nested-PCR.

RESULTS

A greater amount of t(14;18)-positive cells was observed in BM in comparison with PB in 76% of paired samples. The presence and number of t(14;18)-positive cells in BM and PB correlated with lymphoma activity. Significantly higher numbers of lymphoma cells were found in patients under non-remission compared with patients in clinical remission. During non-remission, 10-fold higher numbers were measured at relapse than at diagnosis. During remission, significantly higher levels were found in partial compared with complete remission. During first-line therapy, R/cyclophosphamide/adriamycin/vincristine/prednisone (CHOP) had higher in vivo purging ability than R/fludarabine/mitoxantrone (FM). After R/high-dose cytosine-arabinoside and mitoxantrone (HAM) or R/carmustine/etoposide/cytarabine/melphalan (BEAM), the level of t(14;18)-positive cells dropped below the detection limit in 80% of patients.

CONCLUSIONS

LightCycler qPCR is a reliable method for quantitative molecular monitoring of t(14;18)-positive cells in BM and PB of patients with follicular lymphoma. It reflects the clinical characteristics of patients and allows assessment of response to different treatment regimens on a molecular level.

Concurrent administration of high-dose rituximab before and after autologous stem-cell transplantation for relapsed aggressive B-cell non-Hodgkin's lymphomas

PURPOSE

We investigated the efficacy and safety of administering high-dose rituximab (HD-R) in combination with high-dose carmustine, cytarabine, etoposide, and melphalan chemotherapy and autologous stem-cell transplantation (SCT) in patients with recurrent B-cell aggressive non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Sixty-seven consecutive patients were treated. Rituximab was administered during stem-cell mobilization (1 day before chemotherapy at 375 mg/m(2) and 7 days after chemotherapy at 1,000 mg/m(2)), together with granulocyte colony-stimulating factor 10 mug/kg and granulocyte-macrophage colony-stimulating factor 250 microg/m(2) administered subcutaneously daily. HD-R of 1,000 mg/m(2) was administered again days 1 and 8 after transplantation. The results of this treatment were retrospectively compared with those of a historical control group receiving the same preparative regimen without rituximab.

RESULTS

With a median follow-up time for the study group of 20 months, the overall survival rate at 2-years was 80% (95% CI, 65% to 89%) for the study group and 53% (95% CI, 34% to 69%) for the control group (P = .002). Disease-free survival was 67% (95% CI, 51% to 79%) for the study group and 43% (95% CI, 26% to 60%) for the control group (P = .004). The median time to recovery of absolute neutrophil count to >/= 500 cells/microL was 11 days (range, 8 to 37 days) for the rituximab group and 10 days (range, 8 to 17 days) for the matched control group (P = .001). However, infections were not significantly increased in patients treated with rituximab.

CONCLUSION

The results of this study suggest that using HD-R and autologous SCT is a feasible and promising treatment for patients with B-cell aggressive NHL.

Bone marrow transplantation for lymphoma CR1

PURPOSE OF REVIEW

Despite several reports showing the superiority of autologous stem cell transplantation over conventional chemotherapy in the salvage treatment of non-Hodgkin lymphoma, its use as part of first-line therapy in this disease is still controversial. The review highlights the most relevant studies on autologous stem cell transplantation for non-Hodgkin lymphoma at diagnosis published over the past year.

RECENT FINDINGS

Several recent studies have shown that autologous stem cell transplantation may offer survival benefits in patients with both diffuse large cell lymphoma and follicular cell lymphoma whose prognostic features are poor. An advantage of autologous stem cell transplantation has also been documented for other non-Hodgkin lymphoma subtypes, in particular mantle-cell lymphoma, in which autologous stem cell transplantation is probably the most effective first-line option presently available. Nevertheless, whether autologous stem cell transplantation is definitely better than conventional chemotherapy is still under discussion, and the issue is still less clear, given the new opportunities offered by rituximab combined with chemotherapy. Autologous stem cell transplantation may also benefit from the addition of rituximab as an in vivo purging agent. Thus, large randomized trials are required to fully define the role of autologous stem cell transplantation in first-line treatment for high-risk non-Hodgkin lymphoma. Such trials should compare autologous stem cell transplantation with chemotherapy, both supplemented with rituximab, in the most frequent CD20+ lymphoma subtypes. The up-front use of autologous stem cell transplantation might find support from the recent observation that patients who do not respond to this treatment may still have a good chance of being rescued by reduced-intensity allogeneic transplantation.

SUMMARY

Autologous stem cell transplantation remains a valid research strategy in first-line therapy and, along with new agents and nonmyeloablative allogeneic transplantation, may help to increase the cure rate for high-risk non-Hodgkin lymphoma.

Rituximab and other emerging monoclonal antibody therapies for lymphoma

The recent approval of rituximab, gemtuzumab ozogamicin, alemtuzumab and ibritumomab tiuxetan by the FDA in the US revealed clear evidence that monoclonal antibodies (mAbs) have significant roles in the current treatment of haematologic malignancies. Among the mAbs under clinical development, anti-CD20 mAbs have been most extensively investigated and have shown definitive clinical efficacy. Rituximab is a genetically engineered chimeric anti-CD20 mAb, with mouse variable and human constant regions. Consecutive clinical trials conducted in the US, Europe and Japan have revealed that rituximab is a highly effective agent with acceptable toxicities against indolent and aggressive B cell non-Hodgkin's lymphomas (B-NHLs) as a single agent and in combination with cytotoxic drugs. A recent French Phase III study in elderly patients with untreated aggressive B-NHL suggested that the addition of rituximab to standard CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy increases the complete response rate and prolongs event-free and overall survival. Lymphoma cells are inherently sensitive to radiation. The aim of radioimmunotherapy is to use the mAb to target radiation to lymphoma tissue while minimising toxicity to normal cells. The clinical trials of 90Y ibritumomab tiuxetan and (131)I tositumomab showed they have definitive efficacy in relapsed indolent B-NHL with acceptable toxicities. A recent comparative study in relapsed indolent B-NHL showed that 90Y ibritumomab tiuxetan produces higher response rates than rituximab. In addition, BL22, a recombinant anti-CD22 immunotoxin, showed significant efficacy in patients with chemotherapy-resistant hairy cell leukaemia. MAbs will have significant roles in the treatment of lymphoid malignancies in the future.

B-cell purging in autologous stem-cell transplantation for non-Hodgkin lymphoma

Autologous stem-cell transplantation is a common therapy for B-cell non-Hodgkin lymphoma. However, a concern with the procedure is the potential of malignant cells to reinfuse with the stem-cell graft. Thus attempts have been made to purge, or eliminate, malignant cells from the graft. The oldest, and most well studied, method for prevention of reinfusion is in vitro use of antibodies against B cells that bind or lyse malignant B cells and healthy cells, while leaving T cells and stem cells to be reinfused. In the past 5 years, investigators have used rituximab, an antibody against CD20, to purge malignant cells in vivo without any manipulation in vitro. Both conventional and new techniques have shown promise, but their exact role remains to be defined. We analysed data on the purging of B cells by use of antibodies in the setting of autologous transplantation, with emphasis on the emerging technique of in vivo purging.

Induction of apoptosis and effect on CD20+ using rituximab on autologous peripheral blood stem cell harvests from patients with B cell lymphomas

Purging of neoplastic cells for autologous stem cell transplantation is usually done in vivo by administering chemotherapy and/or other agents before harvesting. It is also possible to decrease malignant cells counts directly in the cell harvest. In this study, we ascertained the effect of anti-CD20 monoclonal antibody and rituximab administration on peripheral blood hematopoietic stem cells. Five samples of stem cell harvests from different patients with B cell lymphoma were obtained. Each sample was divided in two tubes with calcium gluconate (20 mEq/50 microl). Rituximab (1 mg/600,000 mononuclear cells) was added to one of the tubes. Using flow cytometry, CD19, CD20 (B cell markers), and CD95 (apoptosis marker), expression was measured at baseline and 24 h after the addition of rituximab. A one-sided t-test with equal variances was used to analyze the results. Immediately after rituximab addition, CD20 expression became null. No significant difference in variation of CD19 expression was detected after the addition of rituximab (-3.64% control vs. 0.63% rituximab, p = 0.69). Mean variations of percentage of CD95 expression were 2.9% (controls) and 10.52% (rituximab tubes) (p = 0.06). We conclude that rituximab is capable of initiating apoptosis in vitro. We found no decrease in the CD19+ cell count, used as a surrogate marker for CD20+ cells, meaning that, at least in 24 h, apoptosis activation is not capable of decreasing CD20+ cell numbers. In vitro purging of peripheral blood stem cells harvests with rituximab could be part of a broader therapeutic strategy to be offered to lymphoproliferative disorder patients.

Effects of Pretransplantation Treatment With Rituximab on Outcomes of Autologous Stem-Cell Transplantation for Non-Hodgkin's Lymphoma

Purpose

To analyze the effects of preautografting treatment with rituximab (R) on stem-cell mobilization, post-transplantation complications, engraftment, disease-free survival, and overall survival in patients with non-Hodgkin's lymphoma (NHL).

Patients and Methods

Single-institution retrospective comparative outcome analysis in a cohort of 273 relapsed chemosensitive NHL patients of whom 127 (47%) received R pretransplantation.

Results

R was administered a median of 3 months before autologous transplantation. When compared to the nonrituximab group, R patients were older (56 v 50 years; P < .001), and had delays in post-transplantation platelets recovery (39 v 27 days; P = .001). Pretransplantation R did not affect stem-cell mobilization, post-transplantation early complications, duration of hospitalization, or mortality rates at days 30 and 100. In contrast to patients with low-grade NHL, both disease-free and overall survival rates were significantly better when R was included in the pretransplantation salvage therapy for patients with intermediate-grade NHL.

Conclusion

In this large, single-center retrospective analysis, pretransplantation treatment with R was associated with improved survival in patients with intermediate-grade NHL, at the price, however, of a delay in platelet engraftment.

A model of in vivo purging with Rituximab and high-dose AraC in follicular and mantle cell lymphoma

We studied a model of in vivo purging with Rituximab and high-dose (HD) cytarabine in 14 patients with relapsed/refractory follicular lymphoma and two with refractory mantle cell lymphoma enrolled in a program of HD chemotherapy and autotransplant. After two courses of debulking immunochemotherapy with Rituximab, Vincristine and Cyclophosphamide, we used a combination of Rituximab, HD cytarabine and granulocyte colony-stimulating factor for peripheral blood stem cells (PBSC) mobilization. The median number of CD34+ cells collected was 14.69 x 10(6)/kg (range 5.74-73.2). Monitoring of peripheral CD19+ and CD20+ B cells prior to and throughout the purging period showed that a treatment with Rituximab, Vincristine and Cyclophosphamide results in a profound depletion of B cells in peripheral blood. B-cell depletion persists during mobilization with Rituximab and HD cytarabine allowing a collection of PBSC free of B cells (median CD19+ and CD20+ cells counts 0%). Of nine patients PCR positive for bcl-2 or bcl-1 in blood and marrow at the start of immunochemotherapy, all showed PCR-negative PBSC. In conclusion, in patients with indolent lymphoma, the concurrent administration of Rituximab and HD cytarabine is a safe and efficient method to obtain in vivo purged PBSC. Immunochemotherapy prior to mobilization produces B-cell depletion and seems to be a useful preparative step.

Long-term follow-up of indolent lymphoma patients treated with high-dose sequential chemotherapy and autografting: evidence that durable molecular and clinical remission frequently can be attained only in follicular subtypes

PURPOSE

To evaluate the prognostic relevance of molecular monitoring of minimal residual disease in indolent lymphomas receiving high-dose sequential chemotherapy and autografting.

PATIENTS, MATERIALS, AND METHODS

A polymerase chain reaction- (PCR-)based strategy was used to evaluate the presence of residual tumor cells in a panel of 70 indolent lymphoma patients: 40 with follicular (FCL), 14 with small lymphocytic (SLL), and 16 with mantle-cell (MCL) lymphomas. They were treated either with first-line (n = 61) or second-line (n = 9) therapy with an intensified high-dose chemotherapy program followed by peripheral-blood progenitor cells autografting. The Bcl-1, Bcl-2, and immunoglobulin gene rearrangements were used as lymphoma-specific markers. Overall, a molecular marker was obtained from the diagnostic tissue in 60 of 70 patients (86%). Results The collection of PCR-negative cells and the achievement of posttransplantation molecular remission (MR) were common in patients with FCL subtype (54% and 70%, respectively), whereas they were not frequent among SLL and MCL (25% and 12.5%, respectively) patients. With a median molecular follow-up of 75 months, an 88% incidence of relapse was observed among patients never attaining MR. In contrast, relapse incidence was only 8% among patients attaining a durable MR (P <.005). At present, 26 patients (20 with FCL and six with non-FCL) are long-term survivors in absence of clinical and molecular disease.

CONCLUSION

Our results indicate that among indolent lymphomas, FCL and non-FCL subtypes show a significantly different behavior in terms of MR achievement, and MR after intensive chemotherapy and autografting is predictive for a prolonged disease-free survival, whereas persistent PCR positivity is associated with a high risk of relapse.

Efficiency of in vivo purging with rituximab prior to autologous peripheral blood progenitor cell transplantation in B-cellnon-Hodgkin’s lymphoma: a single institution study

BACKGROUND

Rituximab induces clinical response in advanced B-cell lymphoma and is efficient in removing circulating B-cell from peripheral blood. We therefore postulated that rituximab might be a useful in vivo purging agent before high-dose therapy in this setting.

PATIENTS AND METHODS

Fourteen patients with relapsed follicular, marginal zone and mantle cell lymphomas (11, two and one cases, respectively) and a PCR-detectable molecular marker were treated first with rituximab, then a mobilization chemotherapeutic regimen, followed by high-dose therapy with peripheral blood stem cell transplantation. PCR analyses were performed in peripheral blood before rituximab and during follow-up, and in harvest.

RESULTS

Harvests were free of PCR-detectable molecular marker in nine of the 11 studied cases (82%). After high-dose therapy, clinical complete remission was obtained in 13 (93%) patients and molecular remission in 11 (79%). With a median follow-up of 3 years, the 14 transplanted patients were alive, 11 of them remaining in clinical complete remission and eight in molecular remission at last follow-up.

CONCLUSION

Rituximab treatment followed by high dose therapy appears to be effective in achieving complete clinical and molecular response. In vivo harvest purging is predictive of prolonged clinical and molecular remission.

The role of monoclonal antibodies in stem cell transplantation

Monoclonal antibodies directed at the lymphoid antigens have become established treatments for hematological malignancies either alone or in combination with chemotherapy. However, their incorporation in the transplant setting remains investigational. This review focuses on the currently available data for in vitro and in vivo purging with these antibodies as well as their role in modulating graft-versus-host disease (GVHD).

Peripheral blood stem cell mobilization following CHOP plus rituximab therapy combined with G-CSF in patients with B-cell non-Hodgkin's lymphoma

We mobilized peripheral blood stem cells (PBSC) following CHOP plus rituximab (CHOP-R) therapy, and compared with the findings following CHOP therapy without rituximab. All patients were given G-CSF starting from day 11 after CHOP therapy. Patients in the CHOP-R group (n=8) were given rituximab on day 12. Target CD34(+) cells number was collected in a single leukapheresis on day 14, from all the eight patients in the CHOP-R group. PBSC mobilization kinetics, CD34(+) cells yield and colony-forming ability in the graft collection, toxicity during mobilization, and engraftment after transplantation of CHOP-R group were not significantly different from those in the CHOP group (n=8). In all patients given CHOP-R therapy, CD20(+) cells and immunoglobulin heavy chain (IgH) rearrangement in the graft collection were undetectable by flow-cytometric analysis and Southern blot analysis, respectively, but with PCR analysis two of eight grafts were positive for IgH rearrangement. While further studies are needed to evaluate the efficacy of purging and the outcome of patients undergoing autologous transplantation, CHOP-R therapy can be safely and effectively used in the mobilization phase of PBSC collection, without excess clinical toxicity or deleterious effect on PBSC mobilization kinetics or engraftment time.

A simplified approach to stem cell mobilization in multiple myeloma patients not previously treated with alkylating agents

High-dose chemotherapy and autologous stem cell rescue is considered a standard part of initial therapy for patients with multiple myeloma. Therefore, potential transplant candidates are generally treated with dexamethasone-based programs rather than alkylating agents to avoid stem cell toxicity. The optimal mobilizing regimen for patients with multiple myeloma has not been defined. However, aggressive chemotherapy may result in excessive morbidity and cost in this older, immunocompromised population. We retrospectively examined our experience with a well-tolerated regimen of 1.5 g/m(2) cyclophosphamide on day -10 followed by 10 microg/kg G-CSF beginning on day -7 in 50 consecutive patients with multiple myeloma and no prior alkylating agent therapy. Median stem cell collection was 4.88 x 10(6) CD34+ cells/kg per apheresis and 44 patients collected >5 x 10(6) CD34+ cells/kg within 2 days. In 36 patients, more than 10 x 10(6) CD34+ cells/kg were collected including 33 patients who required 1-2 days of collection. One patient required hospitalization for fever/neutropenia and two required weekend apheresis. We conclude that 1.5 g/m(2) cyclophosphamide plus 10 microg/kg G-CSF is a safe, effective, highly predictable mobilizing program that uniformly provided enough stem cells for one transplant and enough stem cells for two transplants.

Patients with high-risk aggressive lymphoma treated with frontline intensive chemotherapy and autografting: evidence of marked differences in outcome between patients with age-adjusted International Prognostic Index scores 2 and 3

BACKGROUND

The goal of the current study was to evaluate the impact of presentation with an age-adjusted International Prognostic Index (aaIPI) score of 2 or 3 on patients with high-risk aggressive lymphoma who are treated with frontline intensive chemotherapy and autografting.

METHODS

Sixty-nine consecutive patients (median age, 40 years) with either B-cell (n = 60) or non-B-cell (n = 9) aggressive lymphoma were treated with high-dose sequential (HDS) chemotherapy and peripheral blood progenitor cell (PBPC) autografting. The patients who were examined had poor prognoses, with aaIPI scores of 2 (n = 37) or 3 (n = 32). The original treatment regimen, sequential delivery of cyclophosphamide, methotrexate, and etoposide, followed by PBPC autografting (o-HDS), was used in the first 32 patients; the program was intensified by the addition of a course of high-dose cytosine arabinoside (C-HDS) in the next 37 patients.

RESULTS

There were 4 toxicity-related deaths-2 in each aaIPI subgroup (treatment-related mortality, 5.8%). The complete remission rate was significantly higher among patients with an aaIPI score of 2 (n = 32 [86%]) compared with those with an aaIPI score of 3 (n = 13 [41%]; P < 0.001). Patients with an aaIPI score of 2 had significantly better outcomes than did patients with an aaIPI score of 3 in terms of both overall survival (78% vs. 34% at 8 years; P < 0.001) and event-free survival (72% vs. 28% at 8 years; P < 0.001). Similar results were observed when the analysis was limited to the 60 patients with B-cell-derived lymphoma. No significant differences in outcome between patients receiving o-HDS and patients receiving C-HDS were observed. Multivariate analysis demonstrated that an aaIPI score of 3 was the only parameter that was significantly associated with poor overall and event-free survival.

CONCLUSIONS

Age-adjusted International Prognostic Index score is applicable to patients with aggressive lymphoma who are treated with frontline intensive chemotherapy and autografting. In addition, upfront use of HDS chemotherapy appears to be beneficial to patients with an aaIPI score of 2 but not to those with an aaIPI score of 3.

Incorporating monoclonal antibodies in blood and marrow transplantation

The development of therapeutic monoclonal antibodies had been a significant advance in the treatment of B-cell non-Hodgkin's lymphoma (NHL). In the setting of blood and marrow transplantation (BMT), initial research was focused on in vitro graft purging. More recently, investigators have designed in vivo purging protocols using rituximab with the goal of obtaining tumor-free grafts. Exciting developments stem from the use of iodine 131 ((131)I)-tositumomab as well as yttrium 90 ((90)Y)-ibritumomab in myeloablative doses in blood and marrow transplantation protocols for high-risk patients. Finally, vigilance towards complications in particular unusual infections is advised given the profound immunosupressive state caused by these antibodies.

The role of stem cell transplantation in the treatment of follicular lymphoma

Follicular lymphoma (FL) is highly sensitive to chemo- and radiotherapy. However, cure can not be achieved with conventional chemotherapy. Results from several large clinical trials indicate that 50-60% of patients treated with high dose chemo-/radiotherapy (HDT) and autologous blood stem cell transplantation (SCT) for relapse after standard chemotherapy have a 3-5-year chance of disease-free survival (DFS). Overall as well as disease-free survival are improved in patients with negative results in sensitive PCR assays for the disease-specific t(14;18) translocation in bone marrow (BM) or peripheral blood samples taken after transplantation. These data compare favourably to historical results with standard dose chemotherapy. The role of high dose therapy and autologous stem cell transplantation in the primary treatment of follicular lymphoma is presently addressed in randomized trials. Patients with refractory disease or relapsing from standard as well as high dose therapy can achieve long term complete remissions (CR) with allogeneic blood stem transplantation mainly due to the graft-versus-lymphoma effect of the donor immune system.

Pilot phase I/II study of new salvage therapy (CHASE) for refractory or relapsed malignant lymphoma

A pilot phase I/II study was conducted as a single-institute trial for evaluation of the feasibility and efficacy of a new salvage chemotherapy, CHASE, for patients with refractory or relapsed lymphoma . The CHASE regimen, consisting of cyclophosphamide, cytosine arabinoside, etoposide, and dexamethasone, was administered every 3 weeks in a maximum of 5 courses. A total of 16 patients were eligible and registered for this study. Myelosuppression was the major toxicity. Although grade 4 leukopenia and grade 3 thrombocytopenia were identified in 15 and 16 patients, respectively, duration of the nadir was brief (median, 3 days). Nonhematological grade 4 toxicity was not observed, and transient elevations of bilirubin and grade 3 aspartate aminotransferase/alanine aminotransferase (AST/ALT) were observed in 2 and 3 courses, respectively, in a total of 57 courses. Complete and partial response rates were 71.4% (10/14) and 7.1% (1/14), respectively. The median percentage of maximal CD34+ cells was 6.1% on day 15, and a median number of 1.88 x 10(6) CD34+ cells/kg per apheresis were obtained. Thirteen patients received high-dose chemoradiotherapy followed by autologous peripheral blood stem cell transplantation. With a median follow-up time of 36 months from the start of CHASE, the overall survival rate for the 16 patients was 66.6%. These results indicated that CHASE is a safe and effective salvage regimen for malignant lymphoma, has sufficient mobilizing effect on peripheral blood stem cells, and warrants further phase II study.

Clinical applications of CD34+ cell-selected peripheral blood stem cells

Peripheral blood stem cells (PBSC) are increasingly used for stem cell transplantation after high dose chemotherapy. CD34+ cell selection has also been done for use in autologous transplantation studies Bone marrow (BM) may contain tumor cells at the time of harvesting, and on re-infusion, these cells could contribute to a subsequent relapse. Similarly, tumor cell contamination of PBSC collections has been found in a number of studies. Therefore, purging contaminating tumor cells may prevent cases of relapse. As most tumor cell types do not express CD34 antigen, one of the most widespread applications of CD34+ cell selection is likely to be in tumor cell purging. Similarly, CD34+ cell selection has aided allogeneic transplantation studies. Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality in cases of allogeneic transplantation. As aGVHD is mediated by donor T cells, removal of T cells from the graft by CD34+ cell selection may ensure prophylaxis against aGVHD. Further, high-dose immunosuppression followed by CD34+ cell-selected stem cell rescue is theoretically reasonable as a therapeutic tool for patients with autoimmune disease resistant to conventional therapy. However, patients given T cell-depleted transplantation have an increased risk of opportunistic infection as well as malignancies related to immunosuppression; therefore, close monitoring is warranted. We describe here clinical applications of CD34+ cell-selected PBSC for a variety of diseases, with special emphasis on the efficacy as well as drawbacks of this novel technique.

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.

Safety and feasibility of CHOP/rituximab induction treatment followed by high-dose chemo/radiotherapy and autologous PBSC-transplantation in patients with previously untreated mantle cell or indolent B-cell-non-Hodgkin's lymphoma

Patients with no prior chemotherapy and with advanced and progressive follicular lymphoma (FCL) or mantle cell lymphoma (MCL) were enrolled into a treatment protocol combining CHOP/rituximab-CHOP therapy with subsequent consolidation high-dose therapy (HDT) to evaluate the safety and feasibility of this treatment. Overall, 15 patients were enrolled and 13 patients completed the entire treatment protocol without major toxicities or increased infectious complications. One patient withdrew consent after achieving complete remission (CR) prior to HDT. One patient was taken off study with signs of disease progression after induction treatment. All patients showed stable engraftment after HDT. Response rates appear to be favorable, indicating an additional effect of rituximab and HDT. Overall, 12 of 13 patients achieved CR/CRu and one patient partial remission. Follow-up of immune reconstitution displayed transient severe combined immunodeficiency with slow normalization of the cellular and humoral compartments without a significant increase of infectious complications. Taken together, high-dose chemotherapy can be safely given following treatment with CHOP+rituximab. Efficacy in this small cohort of patients was encouraging with sustained remissions in both FCL and MCL patients. Upfront HDT should be considered as a therapeutic option especially in young and/or high-risk patients.

Pharmacokinetic study of patients with follicular or mantle cell lymphoma treated with rituximab as 'in vivo purge' and consolidative immunotherapy following autologous stem cell transplantation

BACKGROUND

Little is known about the pharmacokinetics of rituximab in an autologous stem cell transplant (ASCT) setting.

PATIENTS AND METHODS

We evaluated serum rituximab levels in 26 patients with follicular or mantle cell lymphoma treated with a combination of ASCT and immunotherapy. Patients received nine infusions of rituximab (375 mg/m(2)): one dose as an 'in vivo purge' prior to stem cell collection, and two 4-week cycles at 8 and 24 weeks following ASCT. Pre- and post-infusion serum rituximab levels were measured during the purging dose, with doses 1 and 4 of both sets of maintenance rituximab cycles, and 12 weeks and 24 weeks following treatment.

RESULTS

Rituximab levels were detectable after the first infusion, and peaked at a mean concentration of 463.8 micro g/ml after the final dose. Levels remained detectable 24 weeks after completion of treatment. There was a trend toward higher rituximab levels in patients with follicular lymphoma. Serum concentrations achieved during the maintenance cycles were similar to levels observed in patients with measurable lymphoma treated during 'the pivotal trial'. No correlation was observed between serum rituximab levels achieved in the minimal disease state and the risk of later clinical relapse, nor with the ability to achieve a molecular remission following ASCT.

CONCLUSIONS

The finding that patients treated in minimal disease states and at the time of active disease both achieve similar final serum rituximab concentrations after four infusions suggests that the pharmacokinetics are complex, and may not necessarily correlate with disease burden. The precise factors influencing rituximab clearance in patients with lymphoma are unresolved, and this remains an area of active research.

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.

The whys and hows of hematopoietic progenitor and stem cell mobilization

Intentional mobilization of hematopoietic/stem cells into the circulation has improved the efficiency of their collection. Transplantation of mobilized blood stem cells to patients with marrow aplasia results in a faster pace of hematopoietic recovery than transplantation of marrow-derived stem cells. Autologous and allogeneic hematopoietic stem cell transplantation are increasingly performed with blood-derived cells. Donors of both autologous and allogeneic blood stem cells do not always respond well to therapies designed to produce mobilization. Autologous donors may respond poorly as a result of myelotoxic damage inflicted by prior antitumor therapy, but this explanation is not valid for allogeneic donors. The mechanism(s) involved in the process of mobilization are incompletely understood. Until these mechanisms are elucidated, methods to improve mobilization vigor on a rational basis will not be obvious. In the meanwhile, clinical observations may provide some hints regarding the whys and hows of mobilization and permit incremental improvements in this process.

Rituximab: enhancing outcome of autologous stem cell transplantation in non-Hodgkin's lymphoma

High-dose chemotherapy and autologous stem cell transplantation (ASCT) is a potentially curative therapy for younger patients with relapsed aggressive non-Hodgkin's lymphoma, and is under investigation as first-line treatment and as therapy for indolent and mantle cell non-Hodgkin's lymphoma. However, between 40% and 70% of all patients relapse after ASCT because of contamination of the stem cell product or persistence of residual tumor cells. Evidence is emerging that the administration of rituximab as an in vivo purging agent before ASCT is effective in eliminating lymphoma cell contamination, as measured by clearance of bcl-2-positive cells from stem cell harvests. Furthermore, in vivo purging with rituximab does not adversely affect the stem cell yield or function. Maintenance therapy with rituximab post-transplantation has also been explored as a means of eliminating residual tumor cells. Results suggest that rituximab may eradicate minimal residual disease post-transplant and help prevent relapse. The efficacy of both in vivo purging and maintenance therapy with rituximab is currently being investigated in a large, multicenter, randomized trial by the European Group for Blood and Bone Marrow Transplantation in patients with follicular non-Hodgkin's lymphoma. Results from this and other ongoing trials will confirm the full potential of rituximab in ASCT.