Autologous stem-cell transplantation for non-Hodgkin's lymphomas: the role of graft purging and radiotherapy posttransplantation--results of a retrospective analysis on 120 patients autografted in a single institution

Sequential CD19/22 CAR T-cell immunotherapy following autologous stem cell transplantation for central nervous system lymphoma

Chimeric antigen receptor (CAR) T-cell immunotherapy following autologous stem cell transplantation (ASCT) is a promising method for refractory or relapsed multiple myeloma, but explicit data for central nervous system lymphoma (CNSL) are lacking. Here, we treated 13 CNSL patients with ASCT sequential CD19/22 CAR T-cell infusion and simultaneously evaluated the clinical efficacy and toxicity. The 13 CNSL patients analyzed included four primary CNSL and nine secondary CNSL patients. Patients 1 and 10, who had complete remission status before enrollment, maintained clinical efficacy without recurrence. Nine of the remaining 11 patients responded to our protocol with a median durable time of 14.03 months, and the overall response and complete remission rate were 81.81% and 54.55%, respectively. No patient suffered grades 3–4 cytokine-release syndrome (CRS), and only patient 10 experienced severe immune effector cell-associated neurotoxicity syndrome (ICANS). In addition, increases in serum ferritin and interleukin-6 levels were often accompanied by CRS and ICANS. After a median follow-up time of 14.20 months, the estimated 1-year progression-free survival and overall survival rates were 74.59% and 82.50%, respectively. Sequential CD19/22 CAR T-cell immunotherapy following ASCT as a novel method for CNSL appears to have encouraging long-term efficacy with relatively manageable side effects.

INFRADIAPHRAGMAL RADIOTHERAPY IN PATIENTS WITH LYMPHOMA: VOLUME DEFINITION AND SIDE EFFECTS

SUMMARY – Lymphomas are very radiosensitive and radiotherapy (RT) was the first treatment modality that enabled cure. It is the most effective single modality for local control of lymphomas. However, as a local form of treatment, curative intention is only possible if all lymphoma tissue can be incorporated in the volume to be irradiated with the prescribed total irradiation dose. That is why RT is a single modality only in early stage of nodular lymphocyte predominance Hodgkin’s lymphoma and low grade non-Hodgkin’s lymphoma. In most patients, RT can be used as consolidation therapy after chemotherapy or as salvage after failure of chemotherapy. In the past two decades, irradiation techniques have been improved in order to spare critical tissues and reduce toxicity. Although effective, RT is a neglected modality of treatment because of the appearance of new drugs and fear of side effects after irradiation. Radiation has been shown to be effective in the treatment of all stages and forms of lymphoma. Study data are still mostly derived from patients that received supradiaphragmal RT; therefore, there is no agreement about the best management approach in patients with infradiaphragmal lymphoma.

Extended follow-up of autologous bone marrow transplantation with 4-hydroperoxycyclophosphamide (4-HC) purging for indolent or transformed non-Hodgkin lymphomas

Autologous blood or marrow transplantation (ABMT) for low-grade lymphomas can prolong event-free survival (EFS) but requires long-term follow-up. We report one of the longest follow-ups to a prospective transplantation study in such diseases. On a phase II study, 80 patients with low-grade, transformed, or mantle cell lymphoma received ABMT with 4-hydroperoxycyclophosphamide (4-HC) purging as part of initial or salvage therapy. Diagnoses included nontransformed follicular lymphoma in 63% and transformed lymphoma in 15%. With 16.6-year median follow-up for survival, actuarial 10-year EFS and overall survival (OS) were 34% (95% confidence interval [CI], 25%-46%) and 45% (35%-57%). Median EFS and OS were 3.0 and 8.0 years. Early nonrelapse mortality incidence was 8%; myelodysplastic syndrome or leukemia incidence was 4%. Most relapses occurred within 3 years, with a median time to diagnosis of relapse of 1.8 years (range: 0.1-15.6 years). On multivariate analysis, age >50 years, ≥3 prior chemotherapy regimens, and ABMT after relapse were associated with significantly inferior survival. Fifteen patients (19%) were event-free >15 years after transplantation, raising the possibility of a plateau in the progression-free survival curve. Thus, 4-HC-purged ABMT can produce extended remissions in a subgroup of patients with indolent lymphomas.

Augmented high-dose regimen of cyclophosphamide, carmustine, and etoposide with autologous hematopoietic stem cell transplantation for relapsed and refractory aggressive non-Hodgkin's lymphoma

Progressive disease is the major cause of treatment failure after autologous hematopoietic stem cell transplantation for relapsed or refractory non-Hodgkin's lymphoma. An augmented high-dose regimen of cyclophosphamide 7,200 mg/m2, carmustine 300 - 400 mg/m2, and etoposide 2,400 mg/m2 (CBV) was developed in an attempt to improve disease control post-transplant. Sixty-seven adult patients received augmented CBV followed by infusion of unpurged autologous peripheral blood stem cells. Thirty seven patients had relapsed after standard chemotherapy, 28 patients had primary refractory disease, and 2 patients had transformed lymphoma in first partial response. Treatment-related mortality was 4%. Actuarial four year overall survival and progression-free survival were 46+/-8% and 36+/-6%, respectively. Risk factors for disease progression were histologic involvement of marrow by lymphoma and infusion of increased numbers of CD34 + cells per kg in the stem cell autograft. The outcome for patients with relatively chemorefractory disease (defined as 25 - 49% reduction in tumor volume after salvage chemotherapy) was no different than that for patients with chemosensitive disease. Compared to standard high-dose CBV regimens, augmented CBV does not appear to have substantially improved disease control. Prospective study of the association between inferior progression-free survival and infusion of higher CD34 + cell doses in stem cell autografts is warranted.

Current controversies in follicular lymphoma

Follicular lymphoma (FL) is characterized by its responsiveness to initial therapy, a pattern of repeated relapses, and a tendency for histologic progression to a process resembling diffuse, large B-cell lymphoma. Treatment decisions are complicated by the many effective options now available including combinations of conventional chemotherapy and monoclonal antibody, radioimmunotherapy, new targeted agents, and autologous and allogeneic stem cell transplantation. For selected patients, "watch and wait" or involved field irradiation may still be the most appropriate strategy. When therapy is required, a combination of rituximab and conventional chemotherapy results in improved outcomes compared to chemotherapy alone. Radioimmunotherapy alone or in combination with chemotherapy is an attractive strategy for patients with relapsed disease and may prove to be appropriate first line therapy. The role of stem cell transplant in FL requires further investigation. Novel agents with varied mechanisms of action continue to be developed. Enrollment of patients into clinical trials designed to address the many unanswered questions in FL is essential to improving clinical outcomes.

The evolving role of autologous and allogeneic stem cell transplantation in follicular lymphoma

Treatment options for follicular lymphoma have expanded dramatically. The most important relate to the introduction of monoclonal antibodies and the completion of important studies regarding autologous and allogeneic transplantation. The EBMTR-sponsored "CUP Trial" (conventional Chemotherapy, Unpurged autograft, Purged autograft), demonstrated that for patients under age 60 years with recurrent chemotherapy-sensitive disease, autologous stem cell transplantation (ASCT) provides a survival benefit over conventional therapy. Three randomized studies demonstrated that consolidation with autologous transplantation in first remission leads to improvement in progression free survival and perhaps in overall survival, but possibly with an increased risk for secondary MDS. Novel approaches involve the incorporation of rituximab as an in-vivo purging agent or as post-transplant therapy, and the use of radiolabelled monoclonals in the conditioning regimens. Allogeneic stem cell transplantation (alloSCT) has become a more effective option but continues to have a high TRM. Reduced-intensity alloSCT procedures now are being performed at an increasing rate and may have advantages in particular situations. A CIBMTR analysis unfortunately did not show a major advantage in terms of TRM or EFS to non-myeloablative transplantation. Performance status and disease sensitivity remain the major predictors of outcome for allogeneic transplantation.

The significance of minimal residual disease in stem cell grafts and the role of purging: is it better to purge in vivo or in vitro?

Contamination of autologous graft by tumor, in addition to incomplete tumor eradication, can partly explain why relapse remains the commonest cause of treatment failure after autologous stem cell transplantation (ASCT) in patients with malignant hematologic disorders. Monitoring of minimal residual disease (MRD) is now recognized as an important diagnostic tool for assessment either of the response to treatments aimed at maximal cytoreduction and the individual risk of relapse. In order to improve cure rates, many strategies to achieve in vivo or in vitro reduction, if not eradication, of residual disease have been proposed. We discuss the significance of MRD and the role of purging in the ASCT setting, focusing on acute myeloid leukemia, chronic myeloid leukemia, multiple myeloma and follicular lymphoma.

Autologous and allogeneic stem cell transplantation in follicular lymphoma

Follicular non-Hodgkin's lymphomas (NHL) usually present in advanced stage and although frequently are chemotherapy-sensitive remain incurable using conventional approaches. Treatment options are evolving rapidly and now include targeted therapies such as monoclonal antibodies. Recent studies, including the EBMTR-sponsored "CUP Trial" (conventional Chemotherapy, Unpurged autograft, Purged autograft), demonstrate that for patients under age 60 years with recurrent chemotherapy-sensitive disease, autologous stem cell transplantation (ASCT) provides a survival benefit over conventional therapy. Allogeneic stem cell transplantation (alloSCT) has become a more effective option. Although incorporation of TBI into the preparative regimen may increase treatment-related mortality (TRM), relapses appear to be reduced compared to a chemotherapy-alone regimen. Reduced-intensity alloSCT procedures now are being performed at an increasing rate, in part due to a lower risk for TRM. Until more data are available, however, reduced-intensity alloSCT should be considered only in cases where myeloablative conditioning is contra-indicated. There are no clear means for choosing ASCT versus alloSCT, a decision influenced by amount of residual tumor, disease-responsiveness, degree of marrow involvement and extent of prior chemotherapy. ASCT or alloSCT in first remission remains an investigational procedure. Future considerations include incorporation of novel preparative regimens, in vitro purging techinques, anti-lymphoma vaccines, post-transplant immunotherapy and ex vivo-manipulated donor lymphocyte infusions.

Optimal scheduling to reduce morbidity of involved field radiotherapy with transplantation for lymphomas: A Prospective Australasian Leukaemia and Lymphoma Group Study

This study evaluated delivery of involved field radiotherapy (IFRT) with transplantation for lymphomas timed to minimise toxicity. Patients transplanted for lymphoma had infradiaphragmatic disease irradiated pre-transplant and supradiaphragmatic disease post transplant. A total of 31 patients were studied, with a median follow-up duration of 4 years. Transplant conditioning was according to clinician preference. In all, 14 patients had pre-transplant abdominopelvic IFRT and 19 had post transplant IFRT (including three who had pre-transplant IFRT). Grade III-IV haematological toxicity from pre-transplant IFRT occurred in three patients and from post transplant IFRT in 10 patients. Pre-transplant IFRT had no effect on haematological recovery post transplant, but was associated with a trend towards increased gastrointestinal toxicity (P = 0.094). Pneumonitis due to post transplant thoracic IFRT occurred in one patient. Two patients failed in involved sites after completion of protocol radiotherapy. One case of myelodysplasia has been reported. As sequenced in this study, IFRT was feasible and produced a low incidence of severe pulmonary and haematological toxicities. Patient selection, field size and radiotherapy dose warrant further study.

Stem cell transplantation in follicular lymphoma: progress at last?

Follicular non-Hodgkin's lymphomas usually present in advanced stage and although frequently are chemotherapy-sensitive remain incurable using conventional approaches. Treatment options are evolving rapidly and now include targeted therapies such as monoclonal antibodies. Recent studies, including the EBMTR-sponsored 'CUP Trial' (conventional Chemotherapy, Unpurged autograft, Purged autograft), demonstrate that for patients under age 60 years with recurrent chemotherapy-sensitive disease, autologous stem cell transplantation (ASCT) provides a survival benefit over conventional therapy. Allogeneic stem cell transplantation (alloSCT) has become a more effective option. Although incorporation of TBI into the preparative regimen may increase treatment-related mortality (TRM), relapses appear to be reduced compared to a chemotherapy-alone regimen. Reduced-intensity alloSCT procedures are now being performed at an increasing rate, in part due to a lower risk for TRM. Until more data are available, however, reduced-intensity alloSCT should be considered only in cases where myeloablative conditioning is contra-indicated. There are no clear means for choosing ASCT vs alloSCT, a decision influenced by the amount of residual tumor, disease-responsiveness, degree of marrow involvement and extent of prior chemotherapy. ASCT or alloSCT in first remission remains an investigational procedure. Future considerations include incorporation of novel preparative regimens, in vitro purging techniques, antilymphoma vaccines, post transplant immunotherapy and ex vivo-manipulated donor lymphocyte infusions.

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.

Low-Grade Lymphoma

Folicular lymphoma (FL), the second most common subtype of non-Hodgkin lymphoma, shows considerable heterogeneity in its clinical behavior, representative of a biology that appears increasingly complex and diverse. As our knowledge of the molecular basis of FL increases, we strive for an integration between the bench and clinic that yields treatments based on our scientific understanding and biomarkers that allow us to prescribe treatment rationally.

In Section I, Dr. Randy Gascoyne describes the histologic, cytogenetic and biologic features of FL that underlie its clinical variability. Key aspects of the pathologic diagnosis of FL that have particular relevance to the clinician are highlighted. A proposed model for follicular lymphomagenesis and diffuse large B cell lymphoma transformation has emerged and continues to evolve as the molecular story unfolds. A biologic basis for clinical outcome in FL also appears to be forthcoming.

In Section II, Dr. Jane Winter addresses the complex process of selecting among the many treatment options for patients with FL. Previously a simple matter of deciding between oral or intravenous alkylators, clinicians and patients must now struggle to choose among vastly different approaches ranging from “watch and wait” to stem cell transplantation. The introduction of rituximab and radioimmunoconjugates is changing the treatment paradigm, but the optimal approach to integrating these and other new agents remains to be determined. At every decision point, the best approach is always a clinical trial.

In Section III, Dr. Koen Van Besien provides a well-documented update on outcomes associated with autologous and allogeneic stem cell transplantation for FL. The results of trials of autologous stem cell transplantation in first remission and recent data supporting a role for graft purging are discussed. Based on the premise that a graft-versus-lymphoma effect is operative in FL, reduced-intensity allogeneic transplantation is the preferred approach in many cases, and recently reported results are summarized. Criteria for patient selection and the optimal role of transplantation in the overall therapeutic plan for the patient with FL are presented.

Syngeneic hematopoietic stem-cell transplantation for non-Hodgkin's lymphoma: a comparison with allogeneic and autologous transplantation--The Lymphoma Working Committee of the International Bone Marrow Transplant Registry and the European Group for Blood and Marrow Transplantation

PURPOSE

To compare results of syngeneic, allogeneic, and autologous hematopoietic stem-cell transplantation for non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

The databases of the International Bone Marrow Transplant Registry (IBMTR) and the European Group for Blood and Marrow Transplantation were used to identify 89 NHL patients who received syngeneic transplants. These patients were compared with NHL patients identified from the IBMTR and the Autologous Blood and Marrow Transplant Registry who received allogeneic (T-cell depleted and T-cell replete) and autologous (purged and unpurged) transplants.

RESULTS

No significant differences in relapse rates were observed when results of allogeneic transplantation were compared with syngeneic transplantation for any histology. T-cell depletion of allografts was not associated with a higher relapse risk, but was associated with improved overall survival for patients with low-grade and intermediate-grade histology. Patients who received unpurged autografts for low-grade NHL had a five-fold (P =.008) greater risk of relapse than recipients of syngeneic transplants, and recipients of unpurged autografts had a two-fold (P =.0009) greater relapse risk than patients who received purged autografts. Among low-grade NHL patients, the use of purging was associated with significantly better disease-free survival (P =.003) and overall survival (P =.04) when compared with patients who received unpurged autografts.

CONCLUSION

These analyses failed to find evidence of a graft-versus-lymphoma effect, but do provide indirect evidence to support the hypothesis that tumor contamination may contribute to lymphoma relapse, and that purging may be beneficial for patients undergoing autologous hematopoietic stem-cell transplantation for low-grade NHL.

High-dose therapy improves progression-free survival and survival in relapsed follicular non-Hodgkin's lymphoma: results from the randomized European CUP trial

PURPOSE

To determine, in a randomized clinical trial, whether high-dose therapy (HDT) followed by autologous stem-cell transplantation is more effective than standard treatment with regard to progression-free survival (PFS) and overall survival (OS) in patients with relapsed follicular non-Hodgkin's lymphoma; and to assess the additional value of B-cell purging of the stem-cell graft with regards to PFS and OS.

PATIENTS AND METHODS

Patients received three cycles of chemotherapy. Responding patients with limited bone marrow infiltration were eligible for random assignment to three further cycles of chemotherapy (C), unpurged HDT (U), or purged HDT (P).

RESULTS

Between August 1993 and April 1997, 140 patients were registered from 36 centers internationally, and 89 were randomly assigned. Reasons for not randomizing included patient refusal, early progression, or death on induction therapy. With a 69-month median follow-up, the log-rank P value for PFS and OS were.0037 and.079, respectively. For PFS, the hazard ratios (95% CIs) for U versus C, P versus C, and P versus U were 0.33 (0.16 to 0.70), 0.38 (0.19 to 0.79), and 1.02 (0.51 to 2.05), respectively. The hazard ratio (95% CI) for C versus U + P was 0.30 (0.15 to 0.61). Hazard ratios (95% CIs) for OS were 0.43 (0.18 to 1.06), 0.43 (0.18 to 1.02), and 0.72 (0.32 to 1.63). For C versus U + P, the hazard ratio (95% CI) was 0.40 (0.18 to 0.89). Kaplan-Meier estimates (95% CIs) of 2-year PFS for C, U, and P were 26% (8% to 44%), 58% (37% to 79%), and 55% (34% to 75%), respectively. OS at 4 years for C, U, and P are 46% (25% to 67%), 71% (52% to 91%), and 77% (60% to 95%) respectively.

CONCLUSION

HDT significantly improves PFS and OS. There is no clear evidence of benefit through purging.

Role of autologous stem cell transplantation in chronic lymphocytic leukemia

Autologous hematopoietic stem sell transplantation is increasingly considered for treatment of patients with high-risk chronic lymphocytic leukemia. Patients not eligible for allogeneic hematopoietic stem cell transplantation with poor prognosis disease, documented chemosensitivity, and a minimal tumor burden at the time of hematopoietic stem cell transplantation can be treated with autologous hematopoietic stem cell transplantation currently using peripheral blood stem cells. Different purging methods to obtain sources of stem cells free of tumor contamination are currently being evaluated. Major concerns are judicious selection of which patients may benefit from this approach, the subsequent risk of relapse of disease, and the long-term risk of development of secondary malignancies, including myelodysplastic syndrome and acute myelogenous leukemia. Recognizing and reducing the risk factors that contribute to relapse and complications of the procedure should improve outcome after autologous hematopoietic stem cell transplantation. With the increasing use, increasing effectiveness, and low treatment-related mortality associated with nonmyeloablative conditioning regimens, the question of whether a patient should be offered autologous or allogeneic hematopoietic stem sell transplantation can be a difficult one. Defining salvage settings for relapse and implementing a tandem autologous/allogeneic hematopoietic stem cell transplantation approach may provide a method to improve outcome for selected patients.

Autologous and allogeneic transplantation for aggressive NHL

BACKGROUND

Intermediate- and high-grade NHL are generally chemosensitive diseases with high initial response rates to combination chemotherapy. Dose intensification via autologous and allogeneic transplantation provides viable treatment options in specific clinical settings. Currently, autologous transplantation is the standard of care for relapsed but chemosensitive aggressive B-cell NHL. However, tools such as the International Prognostic Index allow risk-adapted analyses, and show that the magnitude of benefit from autologous transplantation differs in lymphoma subsets.

METHODS

Low-risk patients appear to do well regardless of salvage approaches, whereas high-risk patients have suboptimal outcomes with autologous transplantation. In high-risk patients, high-dose chemotherapy with autologous stem-cell transplantation has been examined as part of initial therapy, with long-term data promising but still evolving.

DISCUSSION

A significant concern with autologous transplantation in aggressive and high-grade NHL is the risk of graft contamination with tumor cells. Several investigators have demonstrated the presence of malignant cells in both BM and PBSC, although the clonagenic potential of such cells is unclear. Allogeneic stem-cell transplantation has several potential advantages over autologous transplantation for NHL,including procurement of an uncontaminated stem-cell graft, GvL effects, and the elimination of hematopoietic stem-cell damage and consequent secondary leukemia.

RESULTS

The ideal application of allogeneic transplantation in aggressive and high-grade lymphomas is still unclear; but the lower relapse rates demonstrated in several comparisons of the two approaches make this an exciting area to pursue. Finally, non-myeloablative stem-cell transplantation may broaden the use of allogeneic transplantation by lowering regimen-related mortality while capitalizing on GvL.

The impact of external beam radiation therapy prior to autologous bone marrow transplantation in patients with non-Hodgkin's lymphoma

External beam radiation therapy (XRT) is frequently used to treat refractory disease sites or consolidate remission in patients with relapsed non-Hodgkin's lymphoma (NHL) prior to autologous bone marrow transplantation (ABMT). We report the long-term outcome and toxicities associated with this therapy. We uniformly treated 552 patients with NHL with total body irradiation, high-dose chemotherapy, and anti-B-cell monoclonal antibody-purged ABMT. Of these patients, 152 received XRT to the mediastinum, abdomen, or pelvis (n = 102) or other sites (n = 50) prior to ABMT. In this nonrandomized series, there was no difference in progression-free survival between patients treated with XRT and those not treated with XRT. For patients with indolent histology, there was no difference in overall survival between patients treated with XRT and those not treated with XRT. For patients with aggressive histology, the median overall survival time was 64 months in the XRT patients and 79 months in the patients not treated with XRT (P= .09). The risk of acute transplantation-related deaths was not influenced by prior XRT (P = .68). Of patients who received XRT, 12.5% developed secondary myelodysplasia compared with 5.8% of patients not receiving XRT (P = .01). Patients receiving XRT to the mediastinum or axilla had a significantly higher risk of late respiratory death (P = .002). In conclusion, XRT allows refractory patients to become eligible for transplantation and experience a disease-free survival interval equivalent to that of patients who do not receive XRT. However, a higher incidence of non-relapse-associated deaths was observed in patients who received XRT. Future work should explore alternative conditioning strategies and altered timing of XRT, in an attempt to limit these late toxicities.

High-dose treatment with autologous haemopoietic progenitor cell support for large B-cell, follicular and mantle-cell lymphoma

The purpose of this chapter is to review the available information on the use of high-dose treatment (HDT) in large B-cell, follicular and mantle-cell lymphoma. The last 10 years have seen a dramatic increase in the number of patients receiving high-dose treatment with autologous haemopoietic progenitor cell support for non-Hodgkin's lymphoma. In patients with recurrent large B-cell lymphoma, HDT is now accepted as the 'standard of care', provided responsiveness to conventional chemotherapy at the time of recurrence has been demonstrated. In contrast, the situation in newly diagnosed patients is far from clear. Several phase III studies have been conducted, comparing conventional chemotherapy with either: the same treatment followed by HDT or an abbreviated number of cycles of conventional therapy followed by HDT. The results hitherto have not conclusively shown an advantage for HDT. In mantle-cell and follicular lymphoma, HDT should still be regarded as experimental. Current studies are evaluating the use of anti-CD20, given either as part of the treatment prior to HDT or as maintenance therapy. In view of the propensity for both of these illnesses to involve the bone marrow, a number of studies have addressed the question of in vitro treatment of the stem cell product. The advent of PCR analysis has made it possible to evaluate the significance of 'molecular remission'. In follicular lymphoma, there is a correlation between freedom from recurrence and persistent PCR negativity for bcl-2 rearrangement-containing cells in follow-up bone marrow samples.

Bcl-2 clearance: optimising outcomes in follicular non-Hodgkin's lymphoma

The long median survival time of patients with follicular non-Hodgkin's lymphoma (NHL), means that the efficacy of new treatments are difficult to assess in the short term. Bcl-2 is an inhibitor of apoptosis and overexpression of the bcl-2 gene in the blood or bone marrow is a feature in up to 85% of patients with follicular NHL. Levels of bcl-2(+) cells in the peripheral blood or bone marrow therefore are a useful measure of disease status in such patients and can be detected by polymerase chain reaction (PCR). Complete bcl-2 clearance from the bone marrow (molecular remission) following autologous stem cell transplant (ASCT) for follicular NHL is considered to be an important prognostic factor for disease-free survival. Tumour cell contamination of the stem cell grafts used in ASCT is commonly associated with relapse. This can be addressed by purging the stem cell harvest prior to transplantation. Various methods of in vitro purging after stem cell collection have been shown to reduce the level of contamination but yield is invariably reduced and grafts remain bcl-2 positive. However, in vivo purging with rituximab during the process of collection has been used to obtain bcl-2-negative stem cell harvests without compromising the yield. Rituximab is a monoclonal antibody licensed for treatment of relapsed and refractory low-grade or follicular NHL. Rituximab targets the CD20 antigen, which is found on cells of the B cell lineage. When used for in vivo purging it depletes the peripheral blood of CD20-positive cells and prevents contamination by lymphoma cells. Molecular remission, as measured by bone-marrow bcl-2 clearance, has been achieved in 7/7 patients with follicular NHL at 1 year after treatment with ASCT using rituximab as an 'in vivopurse', followed by rituximab maintenance. Early clinical outcomes are also encouraging.

Autologous stem cell transplantation in follicular non-Hodgkin's lymphoma

The failure of conventional chemotherapy to improve overall survival rates in follicular non-Hodgkin's lymphoma (NHL) has led to the development of alternative treatment regimens. One such regimen is high-dose chemotherapy (HDT) with autologous stem cell transplantation (ASCT). In ASCT stem cells, harvested predominantly from peripheral blood, are used to repopulate the haemopoietic system after high-dose chemotherapy. Comparison of failure-free survival rates following ASCT, with those previously obtained with conventional chemotherapy, suggests a benefit for ASCT in patients who have previously responded to chemotherapy. Other factors that adversely influence the outcome of ASCT include large tumour burden and bcl-2 overexpression. Although ASCT in follicular NHL can prolong the period of remission, relapse is still common and can be caused either by contamination of the stem cell harvest with tumour cells, or regrowth of residual malignant cells not eradicated by the high-dose chemotherapy. Several strategies have been developed to reduce the rate of relapse, including in vitro purging of the stem cell product to remove tumour cells and using allogenic stem cells from HLA-matched donors with no history of malignant disease. While both these methods may have some benefit, they also have limitations. In vitro purging is labour intensive, costly and, as yet, the effect on relapse is unclear. Allogenic stem cell transplants have been associated with a reduced risk of relapse, but this is offset by increased transplant-related mortality. The most promising strategy to reduce the rate of relapse following ASCT is in vivo purging using rituximab, a monoclonal antibody to CD20. Rituximab mobilises mechanisms to kill lymphoma cells, and causes a rapid depletion of B cells from peripheral blood. Rituximab has demonstrated good efficacy as monotherapy in patients with both aggressive and indolent lymphoma and has shown very high response rates (>95%) when used in combination with HDT.

In vivo purging and relapse prevention following ASCT

The combination of high-dose chemotherapy and autologous stem cell transplantation (ASCT) is a potentially curative therapy for patients with relapsed chemosensitive non-Hodgkin's lymphoma (NHL) and is increasingly being considered as a first-line treatment for NHL patients with poor prognosis or poor outcomes from chemotherapy. However, there is a degree of relapse following the latter which is associated with high levels of tumour cell contamination of the stem cells and/or the presence of residual malignant cells in the host following chemotherapy. Reducing the rate of relapse can be achieved by pre-transplant purging of the stem cell graft followed by post-transplant maintenance to minimise residual disease. Various methods of in vitro purging have been shown to reduce, but not eliminate, the level of stem cell contamination and invariably result in a reduced harvest. To date, this has been reflected in disappointing outcomes for the patient. In contrast, in vivo purging with rituximab during the process of stem cell mobilisation and collection does not adversely affect the yield or function of stem cells and shows a significant improvement in the level of tumour cell contamination as measured by bcl-2 clearance. The relapse potential from residual malignant cells in the host can be addressed by a programme of post-transplant rituximab maintenance therapy. In one study 17 patients with follicular lymphoma who underwent ASCT with in vivo rituximab-purged stem cells, followed by rituximab maintenance, have all remained in complete response at a median follow-up of 12.4 months. The optimum in vivo rituximab purging protocol and the precise effect in terms of overall and disease-free survival are currently being evaluated but appear to present an attractive first-line alternative for NHL patients with poor prognosis or poor outcomes following chemotherapy.

High-dose therapy for indolent lymphoma

Stem-cell transplantation (SCT) has become the treatment of choice for patients with relapsed aggressive non-Hodgkin's lymphoma (NHL). However, the role of SCT in the management of patients with indolent NHL remains controversial. Indolent follicular lymphomas are diseases which are generally incurable with conventional therapy. Although patients can survive for prolonged periods, the median duration of first remission is approximately 3 years, and subsequent remissions are progressively shorter with time. Emerging evidence suggests that high-dose chemotherapy with SCT leads to prolonged disease-free and overall survival in a subset of patients with indolent NHL. However, there is increasing concern regarding the toxicity of SCT, especially the long-term risk of developing myelodysplastic syndrome. It is still unclear as to when this approach should be used. Poorer outcomes have been obtained in heavily pretreated patients but encouraging results are being reported for patients undergoing SCT early during the course of their disease. Investigators are now focusing on how to improve SCT efficacy in order to eradicate minimal residual disease. Many ongoing studies are especially exploring the impact of stem-cell purging and novel ablative regimens combined with allogeneic transplantation.

T-cell depletion and autologous stem cell transplantation in the management of tumour stage mycosis fungoides with peripheral blood involvement

Nine patients with tumour stage mycosis fungoides (MF) have been entered into a pilot study of T-cell depletion and autologous stem cell transplantation (SCT). Eight patients had detectable rearrangements of the T-cell receptor (TCR) gamma-gene demonstrated by polymerase chain reaction (PCR)/single-stranded conformation polymorphism (SSCP) in the peripheral blood. The median age was 47 years and the median duration of disease before SCT was 61 months; Peripheral blood progenitor cells were mobilized using high-dose etoposide (1.6 g/m2) and granulocyte colony-stimulating factor (G-CSF). The apheresis products underwent rigorous T-cell depletion with immunomagnetic methods. Double CD34-positive and CD4/CD8-negative selection achieved a median reduction of 3.89 log of T cells. All nine patients have been transplanted. Conditioning included carmustine (BCNU), etoposide and melphalan (BEM) in seven patients and total body irradiation plus etoposide or melphalan in two. Eight patients engrafted promptly and one patient died of septicaemia. All survivors entered complete remission. Seven patients have relapsed at a median of 7 months (2-14) post SCT. However, most patients have relapsed into a less aggressive stage, which has responded to conventional therapy. Four out of seven evaluable patients had detectable TCR rearrangements in the T-cell depleted graft. A T-cell clone was also detected in the peripheral blood before relapse in four cases. Autologous SCT is feasible, safe and can result in complete remission in a significant proportion of patients with tumour stage mycosis fungoides. Despite a short relapse-free survival, most patients achieved good disease control at the time of relapse.

Remission inversion and no transplant-related mortality--a single centre experience of autologous stem cell transplantation in malignant lymphoma

Between 1989 and 1998 93 patients with malignant lymphoma were treated, in our centre, with high-dose chemotherapy and autologous stem cell transplantation. Diagnosis according to the REAL-classification were: 38 patients with high-grade lymphoma (diffuse large B-cell lymphoma (DLCL) (n = 26), anaplastic T-cell (n = 5), lymfoblastic (n = 3) and others (n = 4)), 31 patients with low-grade lymphoma (follicular (n = 18), mantle cell (n = 4), B-CLL (n = 3) and others (n = 6)) and, finally, 24 patients with Hodgkin's disease. The source of stem cells was bone marrow (14 patients), peripheral blood stem cells (64 patients) or a combination of both sources (15 patients). There was no early ( < 100 days) transplant-related mortality. One patient died 11 months post-transplant in unexplained liver failure and all other causes of death were related to relapse of lymphoma. So far, no case of myelodysplastic syndromes or secondary acute leukacmia's has occurred. Overall survival (OS) and progression-free survival (PFS) are: (a) DLCL (26 patients, 4-year probability) OS 40%. PFS 33%; (b) follicular (18 patients, 3-year probability) OS 79%, PFS 52%; (c) Hodgkin's lymphoma (24 patients, 5-year probability) OS 65%, PFS 55%. Out of 52 evaluable patients, 34 (65%) have reached remission inversion. The most important findings are no early transplantation-related mortality, remission inversion in a majority of patients, and so far no cases of secondary myelodysplastic syndromes (MDS) acute myelogenous leukaemias (AML). Concerning OS and PFS, our results seem to be in accordance with other centres.

Postirradiation hyperthermia selectively potentiates the merocyanine 540-sensitized photoinactivation of small cell lung cancer cells

Lung cancer has long been considered a disease that might benefit from the dose escalation of radio/chemotherapy afforded by a stem cell transplant. However, the clinical experience with high-dose chemotherapy and autologous bone marrow transplantation in lung cancer has been disappointing, with most trials showing little or no improvement in long-term survival. Unfortunately, lung cancer has a tendency to metastasize to the bone marrow, and lung cancer cells are known to circulate in the peripheral blood. Therefore, there is concern that autologous stem cell grafts from lung cancer patients may reinoculate recipients with live tumor cells. Photochemical purging of stem cell grafts with Merocyanine 540 (MC540) is highly effective against a wide range of leukemia and lymphoma cells and is well tolerated by normal hematopoietic stem and progenitor cells. Most solid tumor cells (including lung cancer cells), however, are only moderately sensitive or refractory to MC540-mediated photodynamic therapy (PDT). We report here that postirradiation hyperthermia (< or = 42 degrees C, 3 h) potentiates the MC540-mediated photoinactivation of both wild-type (H69) and cisplatin-resistant mutant (H69/CDDP) small cell lung cancer cells by several orders of magnitude, while only minimally enhancing the depletion of normal human granulocyte/macrophage progenitor cells. Our data suggest that postirradiation hyperthermia provides a simple and effective means of extending the utility of MC540-PDT to the purging of stem cell grafts contaminated with lung cancer and possibly other solid tumor cells.

Overview of autologous stem cell transplantation

There has been a dramatic increase in the number of autologous peripheral blood stem cell transplants over the last decade. Faster recovery of cell counts, lesser transplant morbidity, shorter hospital stay and reduced cost compared with marrow autografts have been the main advantages of autologous peripheral blood cell over marrow transplants. In this paper we attempt to review the advances in the biology and mobilization of stem cells, and focus on clinical results of autologous peripheral stem cell and marrow transplants for disease specific sites such as breast cancer, myeloma, autoimmune diseases, germ cell tumors, the acute and chronic leukemias, the non-Hodgkin's lymphomas and Hodgkin's disease. We also discuss transplant related complications, gene therapy and the different methods of purging. This review was intended for autologous peripheral stem cell transplants, however, unavoidably, it also discusses autologous marrow transplantation and aspects common to both procedures.

Ex vivo expansion of CD34-positive peripheral blood progenitor cells from patients with non-Hodgkin's lymphoma: no evidence of concomitant expansion of contaminating bcl2/JH-positive lymphoma cells

The aim of the present study was to evaluate the capacity to expand of hematopoietic stem cell (HSC) samples from eight patients with NHL, and to follow in parallel the fate of tumor cells in four of eight samples still containing bcl2/JH+ tumor cells after CD34+ or CD19-/20-/34+ cell selection. The presence of bcl2/JH+ cells was also investigated after expansion in four of eight samples, two of which were bcl2/JH at harvesting and two which were initially bcl2/JH+ but became bcl2/JH (below the level of PCR detection) after cell selection, to assess a possible reappearance of occult tumor cells after expansion culture. We used culture conditions that we previously had established to allow high level expansion of normal precursors, progenitors and LTC-ICs. In this study, particular attention was given to the role of Flt3-ligand, known to favor the growth of B cells. The expansion conditions were: 1.5 x 10(3) cells/ml in serum-free medium containing stem cell factor (SCF), interleukin-3 (IL-3), IL-6, granulocyte-stimulating factor (G-CSF), erythropoietin (Epo) +/- Flt3-ligand (Flt3-L) for 10 days. After culture, total cells, CFU-GMs, BFU-Es and LTC-ICs were expanded to a mean of 833-, 6.6-, 4.6-, and 1.8-fold, respectively with the cocktail of cytokines not including Flt3-L. When Flt3-L was added, the mean expansion values were 1095-, 31-, 15- and three-fold, respectively. Residual bcl2/JH+ cells present in four of eight samples before expansion were not detected after expansion. Similarly, no tumor cells reappeared after expansion of the two samples which had become negative after selection, as well as in the two samples which were bcl2/JH- at harvesting. These results suggest first that ex vivo expansion of hematopoietic stem cells in patients with non-Hodgkin's lymphoma is feasible without incurring the parallel risk of amplifying tumor cells; second, that Flt3-L did not stimulate the growth of tumor cells while it clearly favored the growth of normal progenitors.

Allogeneic bone marrow transplantation for lymphoma

Registry data show that use of allogeneic transplantation for non-Hodgkin's lymphoma, and to a lesser extent, Hodgkin's disease is increasing. Although no prospective randomized trials have been performed, most comparisons show a significantly lower relapse rate when allogeneic transplant results are compared to results of autologous hematopoietic stem cell transplantation. The lower relapse rate following allogeneic transplantation, as well as several other lines of evidence, support the existence of a graft-versus-lymphoma effect. Nevertheless, in most comparisons, the lower relapse rate following allogeneic transplantation is offset by higher transplant-related mortality. These results make it difficult to find situations where definite overall survival advantages associated with the use of allogeneic transplantation can be demonstrated. The use of low-intensity non-myeloablative regimens for allogeneic transplantation is attracting attention. It is hoped that this approach may harness a graft-versus-lymphoma effect with less morbidity and mortality than conventional allogeneic transplantation, but more data are required to assess the value of this treatment.

Importance of marrow dose on posttransplant outcome in acute leukemia: models derived from patients autografted with mafosfamide-purged marrow at a single institution

Several prospective randomized trials in acute myelocytic leukemia (AML) documented a lower relapse rate with autologous bone marrow transplantation (ABMT) than with conventional chemotherapy. However, they also identified some transplant difficulties, such as failure to collect sufficient numbers of stem cells, slow kinetics of engraftment, and a high transplant-related mortality that diminished or negated positive impact on overall survival. Data for ABMT are inconclusive in acute lymphocytic leukemia (ALL) in adults. We retrospectively analyzed patients with acute leukemia autografted with marrow purged with mafosfamide after January 1983 in our institution. The population comprised 229 consecutive patients; 165 with AML [123 in first remission (CR1), 32 in second remission (CR2)]; 61 with ALL (46 in CR1, 4 in CR2); and 3 with undifferentiated acute leukemia. All patients were autografted with marrow purged with mafosfamide. Mafosfamide was given at a constant dose of 50 microg/mL in 103 and adjusted individually to produce a CFU-GM LD 95 (5% residual CFU-GM post purging) in 126. The outcome was analyzed for correlation with patient characteristics, the disease including cytogenetics, and the graft itself. Prognostic factors identified by multivariate analysis were used to derive a prognostic classification. Patients receiving higher doses of marrow submitted to purging (>5.46 x 10(4) CFU-GM/kg) experienced a lower treatment-related mortality (RR = 0.11, p = 0.005) and a higher leukemia-free (RR = 0.5, p = 0.005) and overall survival (RR = 0.4, p = 0.001). Patients receiving <0.004% CFU-GM of marrow actually infused post purging had a lower relapse rate (RR = 0.51, p = 0.003). Modeling of prognostic groups identified good-, intermediate-, and poor-risk categories. Patients receiving a stem cell dose evaluated before purging of >5.46 x 10(4) CFU-GM/kg and doses actually infused post purging of < or =0.02 x 10(4)/kg had a treatment-related mortality of only 2+/-2%, a leukemia-free survival of 70%, and an overall survival of 77+/-7% at 10 years. In this study of autotransplantation for acute leukemia using mafosfamide-purged marrow, the stem cell dose used for purging and the intensity of purging were the most important factors predicting outcome.

Long-Term Follow-Up of Autologous Bone Marrow Transplantation in Patients With Relapsed Follicular Lymphoma

We report the results of high-dose chemoradiotherapy and anti–B-cell monoclonal antibody-purged autologous bone marrow transplantation (ABMT) in patients with relapsed indolent follicular lymphoma. Between March 1985 and May 1995, 153 patients underwent ABMT using a uniform ablative regimen with cyclophosphamide and total body irradiation and bone marrow (BM) purging. All patients received multiple chemotherapy regimens before ABMT. At BM harvest, only 30% of patients were in complete remission, and overt BM infiltration was present in 47%. The disease-free survival (DFS) and overall survival (OS) are estimated to be 42% and 66% at 8 years, respectively. Patients whose BM was negative by polymerase chain reaction (PCR) for bcl2/IgH rearrangement after purging experienced longer freedom from recurrence than those whose BM remained PCR positive (P &lt; .0001). Continued PCR negativity in follow-up BM samples was also strongly predictive of continued complete remission (CR). The 12-year survival from diagnosis for these 153 patients is 69%. Considering that the median survival from diagnosis and first recurrence of patients with advanced follicular lymphoma are 8 and 5 years, respectively, our results provide evidence that myeloablative therapy and ABMT may prolong overall survival.

Stem cell transplantation for indolent lymphoma

Stem cell transplantation (SCT) has become the treatment of choice for patients with relapsed aggressive non-Hodgkin's lymphoma (NHL). The role of SCT in the management of patients with low-grade NHL remains more controversial, although increasing numbers of patients with advanced-stage follicular lymphoma, mantle cell lymphoma, and chronic lymphocytic leukemia are now undergoing SCT. To date, most patients with NHL have been treated with autologous SCT, currently using peripheral blood stem cells (PBSC) mobilized by chemotherapy and recombinant growth factors. There is increasing concern regarding toxicity of autologous SCT, especially the higher than expected long-term risk of development of myelodysplastic syndrome. This, among other factors, has led to renewed interest in the role of allogeneic SCT for patients with NHL. A major advantage of allogeneic SCT is the potential to exploit a graft-versus-lymphoma effect, and many studies are underway exploring the possibility of manipulating donor cells to maximize T cell responsiveness against lymphoma.

Radiation therapy in the treatment of lymphoma

In most cases, lymphoma is a systemic disease even when detected at an early stage. Although radiation is primarily a local treatment, the exquisite radiosensitivity of lymphomas to radiation has allowed radiotherapy to remain an important component in the management of both indolent and aggressive types of lymphoma. Recent studies established the following points: 1) For early-stage intermediate grade lymphoma, combined modality is the treatment of choice. 2) A large fraction of patients with stage I-II low-grade lymphoma attain long-term disease-free survival with radiation alone. 3) Extranodal mucosa associated lymphoid tissue lymphomas are easily controlled with low-dose involved-field radiotherapy. Preliminary data suggest that even in an advanced-stage, intermediate-grade, adjuvant radiotherapy to bulky sites may improve outcome. This issue merits further study.