Nonablative allogeneic hematopoietic transplantation as adoptive immunotherapy for indolent lymphoma: low incidence of toxicity, acute graft-versus-host disease, and treatment-related mortality

Acute and chronic graft-versus-host disease after ablative and nonmyeloablative conditioning for allogeneic hematopoietic transplantation

In this study, we evaluated the influence of nonmyeloablative and ablative conditioning regimens on the occurrence of acute and chronic graft-versus-host disease (GVHD). One hundred thirty-seven patients undergoing matched-related sibling transplantations received the same GVHD prophylaxis. Myeloablative regimens included intravenous busulfan/cyclophosphamide (n=45) and fludarabine/melphalan (n=29). Patients in the nonmyeloablative group (n=63) received fludarabine/idarubicin/cytarabine, cisplatin/fludarabine/idarubicin, and fludarabine/cyclophosphamide. The actuarial rate of grade II to IV acute GVHD was significantly higher (hazard ratio, 3.6; 95% confidence interval, 1.5-8.8) in patients receiving ablative regimens (36%) compared with the nonmyeloablative group (12%). The cumulative incidence of chronic GVHD was higher in the ablative group (40%) compared with the nonmyeloablative group (14%). The rates were comparable within the first 200 days and were significantly higher in the ablative group beyond day 200 (hazard ratio, 5.2; 95% confidence interval, 1.2-23.2). Nonrelapse and GVHD-related mortality were relatively low in both groups. The use of the described nonmyeloablative preparative regimens was associated with a reduced incidence of grade II to IV acute GVHD and chronic GVHD compared with the busulfan/cyclophosphamide and fludarabine/melphalan transplant regimens. It is interesting to note that nonrelapse mortality with nonmyeloablative regimens in older and more debilitated patients was low (14%) and comparable to that achieved with standard high-dose regimens in younger patients.

Graft-versus-leukemia in a retrovirally induced murine CML model: mechanisms of T-cell killing

The graft-versus-leukemia (GVL) effect, mediated by donor T cells, has revolutionized the treatment of leukemia. However, effective GVL remains difficult to separate from graft-versus-host disease (GVHD), and many neoplasms are GVL resistant. Murine studies aimed at solving these problems have been limited by the use of leukemia cell lines with limited homology to human leukemias and by the absence of loss-of-function leukemia variants. To address these concerns, we developed a GVL model against murine chronic-phase chronic myelogenous leukemia (mCP-CML) induced with retrovirus expressing the bcr-abl fusion cDNA, the defining genetic abnormality of chronic-phase CML (CP-CML). By generating mCP-CML in gene-deficient mice, we have studied GVL T-cell effector mechanisms. mCP-CML expression of Fas or tumor necrosis factor (TNF) receptors is not required for CD8-mediated GVL. Strikingly, maximal CD4-mediated GVL requires cognate interactions between CD4 cells and mCP-CML cells as major histocompatibility complex-negative (MHC II(-/-)) mCP-CML is relatively GVL resistant. Nevertheless, a minority of CD4 recipients cleared MHC II(-/-) mCP-CML; thus, CD4 cells can also kill indirectly. CD4 GVL did not require target Fas expression. These results suggest that CPCML's GVL sensitivity may in part be explained by the minimal requirements for T-cell killing, and GVL-resistance may be related to MHC II expression.

Nonmyeloablative stem cell transplantation for lymphoma

High-dose chemotherapy and allogeneic stem cell transplantation is a potentially curative therapy for younger patients with non-Hodgkin's lymphoma (NHL). The benefits of this therapy, however, are largely offset by the high rate of treatment-related mortality, exceeding 40% in many studies. Risks increase with comorbidities, advanced age, histocompatibility, and disease-related prognostic factors. Given the potential efficacy of graft-versus-malignancy effects against many lymphoid malignancies, we evaluated an alternative strategy utilizing less toxic, nonmyeloablative conditioning regimens to allow engraftment of donor cells, and then exploit the graft-versus-lymphoma (GVL) effects of allogeneic transplantation as the primary therapy. This strategy involved fludarabine-based preparative regimens +/- high-dose rituximab, graft-versus-host disease (GVHD) prophylaxis for 6 months, and donor lymphocyte infusion (DLI) only for progressive or nonresponding disease. Results from these trials confirm the full potential on nonmyeloablative transplantation for patients with NHL.

Immunoablative reduced-intensity stem cell transplantation: potential role of donor Th2 and Tc2 cells

Allogeneic reduced-intensity stem cell transplantation (RISCT) decreases regimen-associated morbidity and mortality, but it is unfortunately still constrained by the same immune T-cell reactions that limit myeloablative transplantation, including graft rejection, graft-versus-host disease (GVHD), and suboptimal graft-versus-leukemia (GVL) or graft-versus-tumor (GVT) effects. Graft rejection is mediated by host T cells, whereas GVHD and GVL/GVT effects are initiated by donor T cells, and to this extent, future advances in RISCT will likely benefit from an ability to modulate both donor and host T-cell immunity. As a step in this direction, we have developed a RISCT approach that first involves chemotherapy-induced host T-cell ablation, and second involves administration of allogeneic inocula enriched for donor CD4(+) Th2 and CD8(+) Tc2 T-cell subsets that in murine studies mediate reduced GVHD. In a pilot clinical trial, "immunoablative" RISCT with human leukocyte antigen (HLA)-matched related allografts resulted in rapid and complete donor chimerism and GVL effects early post-transplant, with GVHD being the primary toxicity. Using this immunoablative RISCT approach, we are now evaluating the feasibility and safety of augmenting allografts with additional donor CD4(+) Th2 cells that are generated in vitro via CD3/CD28 costimulation in the presence of interleukin (IL)-4. We review the biology of host and donor T-cell immunity during allogeneic RISCT and discuss the strategies of host immunoablation and donor Th2 and Tc2 cell therapy as potential means to improve the clinical results in RISCT.

A pilot study of reduced intensity conditioning and allogeneic stem cell transplantation from unrelated cord blood and matched family donors in children and adolescent recipients

Reduced intensity (RI) allogeneic stem cell transplantation (AlloSCT) was initially demonstrated in adults following HLA-matched family and unrelated adult donor AlloSCT. There is little information about RI AlloSCT in children. We report results of a pilot study of RI AlloSCT in 21 recipients (< or =21 years). Age: median 13 (0.5-21) years, 8F:13M, 14 unrelated cord blood units (UCB) (10 4/6, 4 5/6), two related BM (6/6, 5/6), four related PBSC (2 6/6, 2 5/6), and one related BM+PBSC (6/6). RI: fludarabine, busulfan (n=14); fludarabine, cyclophosphamide (n=4); fludarabine, melphalan (n=1); total body irradiation, fludarabine, cyclophosphamide (n=1); or fludarabine, cyclophosphamide, and etoposide (n=1). Graft-versus-host disease prophylaxis: FK506 0.03 mg/kg/day and mycophenolate mofetil 15 mg/kg/q 12 h. UCB median nuc/kg and CD34/kg was 4.3 x 10(7)/kg (0.9-10.8) and 1.9 x 10(5)/kg (0.3-6.9), and related BM/PBSC median nuc/kg and CD34/kg was 8.3 x 10(8) (4.7-18.9) and 5.0 x 10(6)/kg (4.6-6.4). Maximal chimerism following unrelated cord blood transplantation, 100% x 7, 98% x 1, 95% x 2, 55% x 1, and 0% x 3; related PBSC/BM, 100% x 5, 65% x 1, and 55% x 1. Graft failure occurred in 5/21 (24%). In summary, RI AlloSCT in children is feasible and tolerable (< or =25% GF) and results in > or =85% of recipients initially achieving > or =50% donor chimerism.

BEAM-alemtuzumab reduced-intensity allogeneic stem cell transplantation for lymphoproliferative diseases: GVHD, toxicity, and survival in 65 patients

We report the outcomes of reduced-intensity allogeneic stem cell transplantation using BEAM-alemtuzumab conditioning (carmustine, etoposide, cytosine arabinoside, melphalan, and alemtuzumab 10 mg/d on days -5 to -1) in 6 United Kingdom transplant centers. Sixty-five patients with lymphoproliferative diseases underwent sibling (n = 57) or matched unrelated donor (n = 8) transplantation. Sustained donor engraftment occurred in 60 (97%) of 62 patients. Of the 56 patients undergoing chimerism studies, 35 (63%) had full donor chimerism. Overall, 73% were in complete remission (CR) after transplantation. At a median follow-up of 1.4 years (range, 0.1-5.6 years), 37 remain alive and in CR. Acute graft-versus-host disease (GVHD) occurred in 11 (17%) of 64, grades I-II only. Estimated 1-year transplantation-related mortality (TRM) was 8% for patients undergoing first transplantation but was significantly worse for those who had previously undergone autologous transplantation. Six patients relapsed (estimated 2-year relapse risk, 20%). Histologic diagnosis (mantle cell lymphoma and high-grade non-Hodgkin lymphoma) and age at transplantation (> 46 years) were significantly associated with higher relapse risk and worse event-free survival. Relapse did not occur in any patient who developed acute or chronic GVHD. This study demonstrates that reduced-intensity allogeneic stem cell transplantation for lymphoproliferative diseases using a BEAM-alemtuzumab preparative regimen is associated with sustained donor engraftment, a high response rate, minimal toxicity, and a low incidence of GVHD.

Treosulfan and fludarabine: a new toxicity-reduced conditioning regimen for allogeneic hematopoietic stem cell transplantation

New conditioning regimens are being explored to reduce toxicity and enable allogeneic bone marrow transplantation in patients not eligible for conventional transplantation. We have investigated treosulfan, an alkylating agent, with the aim of developing an efficient and reliable but less-toxic conditioning regimen. A series of 30 patients who were not eligible for standard conditioning therapy received transplants from HLA-matched related (n = 14) or unrelated (n = 16) donors after administration of treosulfan 10 g/m2 intravenously daily for 3 days and fludarabine 30 mg/m2 intravenously daily for 5 days. Patients receiving grafts from unrelated donors also were given rabbit antithymocyte globulin 10 mg/kg intravenously daily for 3 days. All patients achieved prompt neutrophil and platelet recovery. Extramedullary toxicity was generally mild with Common Toxicity Criteria (CTC) grade 3 or 4 attributable to the conditioning seen only with transaminases. Complete donor chimerism was achieved by 90% of the patients. Acute graft-versus-host disease (GVHD) grade III or IV developed in 14% of the patients and chronic GVHD in 39%. An estimated overall survival rate of 73% and an event-free survival rate of 49% have been reached after a median of 22 months (range, 7.4-33.4 months). In summary, the combination of treosulfan and fludarabine is a safe and efficient conditioning regimen.

Nonablative allogeneic stem cell transplantation for chronic lymphocytic leukemia: impact of rituximab on immunomodulation and survival

OBJECTIVE

To investigate the graft-vs-leukemia effect of allogeneic stem cell transplantation after a nonablative conditioning regimen as treatment for patients with chronic lymphocytic leukemia.

PATIENTS AND METHODS

Patients were eligible to treatment if they were refractory or recurred after a prior response to fludarabine. Seventeen patients were treated. All patients received a preparative regimen of fludarabine (30 mg/m(2) daily for 3 days) and intravenous cyclophosphamide (750 mg/m(2) daily for 3 days). Ten patients received rituximab in addition to chemotherapy. The median time from diagnosis to transplant was 67 months. Nine of 17 patients had refractory disease.

RESULTS

All patients had engraftment of donor cells. Eleven (65%) did not require platelet transfusions. Ten patients with persistent disease underwent immunomanipulation to augment GVL effects including immunosuppression withdrawal and donor lymphocyte infusion with or without rituximab treatment. Seven of these 10 patients had a complete response and 2 had a partial response; 8 of these 9 responders had received rituximab with their immunomanipulation process. The final response was complete remission in 12 and partial remission in 4 patients for an overall response rate of 94%. Overall survival was 100% for patients who received the combined chemo-rituximab conditioning regimen, vs 14% for those who received chemotherapy alone (p=0.03).

CONCLUSION

Our results indicate that a pronounced GVL effect occurs after nonmyeloablative allogeneic hematopoietic transplantation for advanced CLL. This activity might be facilitated by rituximab. Prospective controlled trials are needed to define the role of nonablative allogeneic hematopoietic transplantation for treatment of this disease.

Nonablative allogeneic stem-cell transplantation for advanced/recurrent mantle-cell lymphoma

PURPOSE

Patients with relapsed mantle-cell lymphoma have poor prognosis and short survival. Our aim was to determine the efficacy of nonablative allogeneic stem-cell transplantation in patients with relapsed mantle-cell lymphoma.

PATIENTS AND METHODS

Eighteen patients were treated in one of two consecutive trials. Thirteen patients underwent a conditioning regimen of fludarabine (30 mg/m2 daily for 3 days), cyclophosphamide (750 mg/m2 daily for 3 days), and high-dose rituximab. For the remaining five patients, the conditioning regimen consisted of cisplatin (25 mg/m2 daily for 4 days), fludarabine (30 mg/m2 daily for 2 days), and cytarabine (1,000 mg/m2 daily for 2 days). Tacrolimus and methotrexate were used for graft-versus-host disease prophylaxis.

RESULTS

The median age was 56.5 years. Patients underwent a median of three prior chemotherapy regimens. Prior autologous transplantation failed in five (28%) patients and 16 (89%) had chemosensitive disease. Donor cell engraftment occurred in all patients. Eight patients (44%) required no platelet or RBC transfusion, and acute graft-versus-host disease of greater than grade 2 did not develop in any patient. The day-100 mortality was 0%. Complete remission (CR) occurred in 17 patients. Three patients progressed, and one was reinduced into continuous CR with donor lymphocyte infusion. With a median follow-up period of 26 months, the actuarial probability of current-event-free-survival at 3 years was 82% (95% CI, 65% to 99%).

CONCLUSION

Our data suggest that nonablative allogeneic transplantation is a safe and potentially effective strategy for patients with relapsed and chemosensitive mantle-cell lymphoma.

Rapid induction of complete donor chimerism by the use of a reduced-intensity conditioning regimen composed of fludarabine and melphalan in allogeneic stem cell transplantation for metastatic solid tumors

We evaluated the feasibility and efficacy of a reduced-intensity conditioning (RIC) regimen of fludarabine and melphalan to achieve rapid complete donor chimerism after allogeneic stem cell transplantation (SCT) in patients with metastatic solid tumors. Between January 1999 and January 2003, 8 patients with metastatic breast cancer (BC) and 15 with metastatic renal cell carcinoma (RCC) underwent allogeneic SCT after an RIC regimen of 5 days of fludarabine and 2 days of melphalan. Filgrastim-mobilized stem cells from HLA-identical related or unrelated donors were infused. Prophylaxis for graft-versus-host disease (GVHD) consisted of tacrolimus and methotrexate. All 22 evaluable patients had 100% donor chimerism at day 30 and at all measurement times thereafter. One patient died 19 days after SCT. Nine patients (39%) had grades II to IV acute GVHD and 10 patients (43%) had chronic GVHD. Five patients (22%) died of nonrelapse treatment-related complications. Treatment-related disease response was seen in 10 patients (45%), with 3 complete responses, 2 partial responses, and 5 minor responses. Fludarabine-melphalan is a feasible and effective RIC regimen for allogeneic SCT in metastatic BC and RCC. It induces rapid complete donor chimerism without the need for donor lymphocyte infusion. Tumor regression associated with GVHD is consistent with graft-versus-tumor effect.

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.

Bone marrow as stem cell source for allogeneic HLA-identical sibling transplantation following reduced-intensity preparative regimen

OBJECTIVE

Reduced-intensity conditioning regimens (RIC) and peripheral blood stem cells (PBSC) are increasingly used for allogeneic stem cell transplantation (allo-BMT). RIC has been shown to allow engraftment with minimal early transplant-related mortality (TRM). However, in the context of RIC, the use of bone marrow (BM) as stem cell source is still little evaluated.

PATIENTS AND METHODS

In this report, we analyzed the outcome of 32 high-risk patients with hematological malignancies who received an HLA-identical sibling allo-BMT after RIC including fludarabine, busulfan, and anti-thymocyte globulin (ATG).

RESULTS

Sustained neutrophil and platelet recovery occurred at a median of 13 days (range, 10-19) and 17 days (range, 0-45) respectively. Early and durable full donor chimerism could be established as soon as the first month after allo-BMT. Also, a sustained and early CD8(+) T-cell recovery was observed, but the CD4(+) T-cell compartment remained profoundly low. The cumulative incidences of grade II-IV acute GVHD and chronic GVHD were 26% (95% CI, 11-41%) and 31% (95% CI, 15-47%) respectively. The overall cumulative incidence of TRM was 28% (95% CI, 12-44%) occurring mainly in patients aged over 50. In this setting, GVHD showed a protective effect on disease progression or relapse with better progression-free survival for patients with GVHD as compared to patients without GVHD (p=0.03).

CONCLUSIONS

Collectively, these results confirm that the use of BM grafts for RIC is feasible with durable donor engraftment and no detrimental GVHD.

Immunologic recovery after hematopoietic cell transplantation with nonmyeloablative conditioning

OBJECTIVE

We studied immune reconstitution in 51 recipients of HLA-identical hematopoietic cellular transplant (HCT) after nonmyeloablative conditioning compared to a reference group of 67 recipients after myeloablative conditioning.

METHODS

Nonmyeloablative conditioning consisted of 2 Gy total-body irradiation+/-fludarabine and postgrafting cyclosporine and mycophenolate mofetil. All patients received G-CSF-mobilized peripheral blood mononuclear cells. Patients were followed with serial assessments of lymphocyte subset counts, antibody levels, virus-induced lymphoproliferation, and limiting-dilution assays for cytomegalovirus (CMV) T helper (T(H)) cells. Rates of infections over the first year after transplant were calculated.

RESULTS

During the first 180 days, absolute lymphocyte subset counts were similar (except higher total and memory B cell counts on day 80 in nonmyeloablative patients). At 1 year, however, total and naïve CD4 counts, and naïve CD8 counts, were higher in myeloablative patients. The levels of antibodies were similar at all time points and after vaccinations. The function of CD4 cells assessed by virus-induced lymphoproliferation was similar. However, the absolute counts of CMV T(H) cells were higher at days 30 and 90 (p=0.002 and p=0.0003, respectively) after nonmyeloablative conditioning. The rates of definite infections were lower for nonmyeloablative patients during the first 90 days, but were higher later. The higher number of CMV-specific T cells days 30 and 90 after nonmyeloablative HCT coincided with a lower rate of CMV infections during that time.

CONCLUSION

The immunity of nonmyeloablative HCT recipients appears better than the immunity of conventional HCT recipients early, but not late, after HCT.

Allogeneic peripheral blood stem cell transplantation for high-risk non-Hodgkin's lymphoma

A high incidence of nonrelapse mortality (NRM) has limited the use of allogeneic transplantation for poor prognosis non-Hodgkin's lymphoma (NHL). We sought to improve the outcome of allografting by utilizing Filgrastim-mobilized peripheral blood stem cells (PBSC) in combination with either standard ablative or reduced-intensity conditioning. A total of 21 patients with intermediate/high-grade lymphoma and seven patients with low-grade histology were enrolled on protocols using PBSC. All patients were considered high risk for recurrence and/or NRM because of age >50 (n=16), refractory disease (n=17), failed autologous transplant (n=11) and abnormal organ function (n=2). In all, 17 patients received ablative regimens and 11 received modified conditioning including fludarabine, intravenous busulfan and ATG. Tacrolimus and mini-dose methotrexate were used for graft-versus-host-disease (GVHD) prophylaxis. Median follow-up was 38 months. Disease-free and overall survival were 57 and 58%. Seven of the 11 patients who relapsed after a previous transplant remain disease free. Four of the 10 patients with recurrent/persistent disease post transplant responded to additional therapy including withdrawal of immunosuppression+/-DLI. These results support a potent graft-versus-lymphoma effect and suggest that patients who relapse after an autologous transplant can be salvaged with an allogeneic transplant.

HLA-matched unrelated donor hematopoietic cell transplantation after nonmyeloablative conditioning for patients with hematologic malignancies

A hematopoietic cell transplantation (HCT) approach was developed for elderly or ill patients with hematologic malignancies that employed nonmyeloablative conditioning to avoid common regimen-related toxicities and relied on graft-versus-tumor effects for control of malignancy. Eighty-nine patients, median age 53 years, were given fludarabine (90 mg/m2) and 2 Gy total body irradiation. Marrow (n = 18) or granulocyte colony-stimulating factor (G-CSF)-stimulated peripheral blood mononuclear cells (G-PBMCs; n = 71) were transplanted from unrelated donors matched for human leukocyte antigen A (HLA-A), -B, -C antigens and -DRB1 and -DQB1 alleles. Postgrafting immunosuppression included mycophenolate mofetil and cyclosporine. Donor T-cell chimerism was higher for G-PBMCs compared with marrow recipients. Durable engraftment was observed in 85% of G-PBMCs and 56% of marrow recipients. Cumulative probabilities of grade II, III, and IV acute graft-versus-host disease (GVHD) were 42%, 8%, and 2%, respectively. Nonrelapse mortality at day 100 and at 1 year was 11% and 16%, respectively. One-year overall survivals and progression-free survivals were 52% and 38%, respectively. G-PBMC recipients had improved survival (57% vs 33%) and progression-free survival (44% vs 17%) compared with marrow recipients. HLA-matched unrelated donor HCT after nonmyeloablative conditioning is feasible in patients ineligible for conventional HCT. G-PBMCs conferred higher donor T-cell chimerism, greater durable engraftment, and better progression-free and overall survivals compared with marrow.

The graft versus leukemia response after allogeneic hematopoietic stem cell transplantation

It is now well established that the efficacy of allogeneic hematopoietic stem cell transplant for eradicating a variety of hematologic malignancies is related to antitumor activity mediated by donor immune cells contained in the stem cell graft. Recent studies have provided fundamental insights into the nature of the effector cells and target molecules that are responsible for the graft versus tumor effect. T cells specific for minor histocompatibility antigens can mediate potent antitumor activity but are also responsible for graft versus host disease (GVHD). The molecular characterization of minor antigens has suggested ways of potentially separating antitumor activity from GVHD. The challenge for the future is to continue to build on our understanding of the allogeneic graft versus tumor effect and develop strategies that can be incorporated into clinical practice to augment this effect without GVHD.

Long-term effect of a watch and wait policy versus immediate systemic treatment for asymptomatic advanced-stage non-Hodgkin lymphoma: a randomised controlled trial

BACKGROUND

Neither chemotherapy with a single-alkylating agent nor aggressive combination chemotherapy cures advanced stage low-grade non-Hodgkin lymphomas, even when combined with radiotherapy. Our aim was to compare administration of immediate chlorambucil treatment with a policy of delaying chlorambucil until clinical progression necessitated its use, in asymptomatic patients with advanced-stage, low-grade non-Hodgkin lymphoma.

METHODS

309 patients with asymptomatic, advanced-stage, low-grade non-Hodgkin lymphomas were recruited from 44 UK centres between Feb 1, 1981, and July 31, 1990. 158 patients were randomised to receive immediate systemic therapy with oral chlorambucil 10 mg per day continuously. The remaining 151 were randomised to an initial policy of observation, with systemic therapy delayed until disease progression. In both groups, local radiotherapy to symptomatic nodes was allowed.

FINDINGS

Median length of follow-up was 16 years. Overall survival or cause-specific survival did not differ between the two groups (median overall survival for oral chlorambucil 5.9 [range 0-17.8] years and for observation 6.7 [0.5-18.9] years, p=0.84; median cause-specific survival 9 [0-17.8] years and 9.1 [0.67-18.9] years, respectively p=0.44). In a multivariate analysis, age younger than 60 years, erythrocyte sedimentation rate (ESR) 20 mm/h or less, and stage III disease, conferred significant advantages in both overall survival (p<0.0001, 0.03, and 0.03, respectively) and cause-specific survival (p=0.002, 0.008, and 0.001, respectively). In the observation group, at 10 years' follow-up, 19 patients were alive and had not received chemotherapy. The actuarial chance of not needing chemotherapy (non-lymphoma deaths censored) at 10 years was 19% (40% if older than 70 years).

INTERPRETATION

An initial policy of watchful waiting in patients with asymptomatic, advanced stage low-grade non-Hodgkin lymphoma is appropriate, especially in patients older than age 70 years.

Rituximab reduces relapse risk after allogeneic and autologous stem cell transplantation in patients with high-risk aggressive non-Hodgkin's lymphoma

High-dose chemotherapy and autologous stem cell transplantation (SCT) have limited success in patients with refractory aggressive lymphoma. Allogeneic SCT may offer some advantage in this setting by providing graft-versus-lymphoma effect, but the relapse risk remains substantial. In this study, we evaluated the safety and efficacy of rituximab administration after SCT in patients at high-risk for post-transplant relapse, in order to reduce relapse risk. Twenty-eight patients were included with the intent to treat them with rituximab after autologous (n = 16) or allogeneic (n = 12) SCT. Twenty-four were given rituximab starting a median of 47 d post SCT. Three died of SCT complications prior to therapy. Nine patients not achieving a complete remission (CR) post SCT converted to CR with rituximab and with the onset of graft-versus-host disease (GVHD) in three. With a median follow-up of 12 months (range, 3-33 months) the estimated 2-year overall survival and disease-free survival was 85 +/- 7% and 55 +/- 13% respectively. When only those patients who were actually treated are analysed, these rates were 95 +/- 7% and 64 +/- 13% respectively. The relapse risk was 35 +/- 14%. Seven patients had recurrent neutropenia episodes associated with severe hypogammaglobulinaemia, which were further prevented with intravenous immunoglobulin. None of the 10 allogeneic SCT recipients treated with rituximab had severe GVHD. Rituximab may be an effective adjuvant therapy after SCT to reduce the relapse rate and improve the outcome in high-risk aggressive lymphoma. Larger scale comparative trials are necessary to better define its role in SCT.

Nonmyeloablative transplantation for lymphoma

Nonmyeloablative stem cell transplantation, also referred to as minitransplantation or reduced-intensity transplantation, is a novel approach to lymphoma treatment offering the lure of harnessing graft-versus-lymphoma (GVL) effects while decreasing regimen-related toxicity. The general concept is to provide a sufficiently immunosuppressive and moderately myelosuppressive treatment regimen to allow donor and host hematopoietic coexistence or chimerism. The most popular regimens incorporate a purine analog (eg, fludarabine) and an alkylating agent (eg, cyclophosphamide or melphalan). Newer regimens include the monoclonal antibody alemtuzumab, which may reduce the incidence of acute graft-versus-host disease (GVHD). Early reports demonstrate a GVL effect; however, the underlying lymphoma subtype and pace of disease often dictate which patients can capitalize on GVL benefits. Clinical reports show mixed results, which may reflect variations in patient selection. Although most patients successfully engraft, the effect on lymphoma control and GVHD must be evaluated carefully. Future investigations continue to delineate the optimal timing of nonmyeloablative transplantation, the optimal patient population, the optimal preparative regimen, and the optimal GVHD prophylaxis. Supportive care remains a critical component of management because the reduced-intensity regimens do not abrogate the risk of serious infection and many do not appear to decrease the incidence of chronic GVHD. Nonmyeloablative hematopoietic stem cell transplantation may broaden the applicability of allogeneic transplantation in malignant lymphomas, especially for indolent subtypes.

Induction of graft-versus-autoimmune (GVA) disease effect against refractory psoriasis by complete donor-type chimerism and graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

A 67-year-old man with AML, who had a 21-year history of psoriasis without remission, received a reduced-intensity transplantation from an HLA-identical sibling. The preparative regimen consisted of busulfan and fludarabine. Graft-versus-host-disease (GVHD) prophylaxis was cyclosporine and methotrexate. Psoriasis was completely resolved on day 18. The subsequent clinical course was uneventful until day 42, when psoriasis recurred at the same sites as before RIST. Peripheral blood examined on day 63 showed mixed chimerism with 54% recipient type. Cyclosporine was rapidly tapered off over the next 2 weeks. On day 90, 100% donor-type chimerism was confirmed. Subsequently, psoriasis improved simultaneously with the occurrence of mucositis and rash as a manifestation of GVHD. Scattered erythematous patches of psoriasis disappeared again by day 105. We initiated 0.5 mg/kg prednisolone on day 119, and resumed cyclosporine on day 133. At 7 months after RIST, he still suffers from chronic GVHD, but his psoriasis remains in remission for the first time in 21 years. The anti-psoriasis effect of the conditioning is mild and transient, while the graft-versus-autoimmunity effect, related to the induction of complete donor-type chimerism and GVHD, is more profound and persisting. A graft-versus-autoimmunity effect lies in the delicate balance between alloimmunity and immunosuppressant used for GVHD prophylaxis/treatment.

A single intravenous infusion of apoptotic cells, an alternative cell-based therapy approach facilitating hematopoietic cell engraftment, did not induce autoimmunity

Previously, we reported that intravenous infusion of apoptotic leukocytes facilitated bone marrow (BM) engraftment across major histocompatibility barriers. This cell-based therapeutic approach is of great interest for stem cell therapy across histocompatibility barriers. Autoimmunity associated with apoptotic cell administration may, however, limit the use of this approach. Indeed, autoantigens are concentrated on the surface of apoptotic cells, and defective clearance of apoptotic bodies is associated with the occurrence of systemic autoimmune disease. In consequence, we assessed the autoimmune responses raised against ubiquitous double-stranded DNA (dsDNA) and cardiolipin autoantigens following a single intravenous infusion of apoptotic cells simultaneously to allogeneic BM administration. No difference was observed between levels of natural circulating immunoglobulin M (IgM) (anti-dsDNA and anti-cardiolipin) autoantibodies found in mice receiving allogeneic BM alone and those found in mice receiving apoptotic cells also. Pathogenic IgG autoantibody titers after apoptotic cell infusion were 9- to 200-fold lower than autoantibody titers found in lupus-prone mice and not different from titers detected in BM grafted mice. Kinetic analysis of autoantibodies after transplantation did not demonstrate any immunization against tested autoantigens after apoptotic cell infusion. Finally, neither immune complex deposition nor specific lesions were observed in the renal glomeruli of mice infused with apoptotic cells 9 months post-BM transplantation. Overall, these results show no specific toxicity of a single infusion of apoptotic cells administrated simultaneously to BM and may also shed light on factors influencing the immunogenic properties of apoptotic cells.

Graft-versus-host disease after nonmyeloablative versus conventional hematopoietic stem cell transplantation

It is unknown whether the severity, timing, and quality of graft-versus-host disease (GVHD) may be different after nonmyeloablative as compared with myeloablative hematopoietic stem cell transplantation (HSCT). Therefore, GVHD incidence, morbidity of skin, liver, and gut, requirements for immunosuppressive therapy, and survival were retrospectively analyzed in 44 patients who underwent nonablative HSCT and 52 who underwent ablative HSCT (median ages, 56 and 54 years, respectively). The nonablative transplantation regimen consisted of low-dose total body irradiation (TBI), preceded in some patients by fludarabine administration and followed in all patients by immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CSP). Those who underwent myeloablative HSCT were prepared with different TBI- and non-TBI-containing regimens and received CSP plus methotrexate or MMF for GVHD prophylaxis. The cumulative incidence of grades II-IV acute GVHD was lower after nonablative transplantation (64% vs 85%; P =.001), but there were no differences in the cumulative incidence of chronic GVHD requiring treatment (73% vs 71%; P =.96). Nonablative transplantation was associated with the delayed initiation of steroid treatment for GVHD (0.95 months vs 3.0 months; P <.001) and with the use of fewer systemic immunosuppressants in the first 3 months after transplantation (P </=.04). This corresponded to more prevalent skin and more severe gut morbidity 6 to 12 months after nonablative transplantation. Our results show that nonablative HSCT is associated with a syndrome of acute GVHD occurring after day 100 in many patients. This "late-onset acute GVHD" should be taken into consideration in the design of prospective studies comparing GVHD resulting from the two types of transplantation procedures.

High complete response rate after allogeneic hematopoietic stem cell transplantation with reduced-intensity conditioning regimens in advanced malignant lymphoma

The possible advantage of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a graft-versus-lymphoma effect. We explored the feasibility and efficacy of allo-HSCT with reduced-intensity (RI) regimens in advanced malignant lymphoma (ML). A total of 20 patients with indolent (n=9) or aggressive lymphoma (n=11) received allo-HSCT with an RI regimen (RIST). The preparative regimen consisted of a combination of purine analog and alkylating agent with or without antithymocyte globulin. A total of 11 patients had chemorefractory disease, seven had chemosensitive relapsed disease and two had residual disease. All of the patients received G-CSF-mobilized blood stem cells from HLA-matched siblings. Of the 20 patients, 19 achieved engraftment with acceptable regimen-related toxicities. Seven patients developed grade II-IV acute GVHD and 15 developed chronic GVHD. Of the 15 patients with evaluable disease, 12 achieved a complete response. One died of invasive fusariosis, four subsequently died of GVHD complicated with fungal infection and one died of progressive disease. With a median follow-up of 358 days, the Kaplan-Meier estimates for 1-year overall and progression-free survival were both 70%. The high response rate with low relapse observed in this study suggests that RIST may be an effective alternative curative treatment for patients with advanced ML.

Graft-versus-host disease, donor chimerism, and organ toxicity in stem cell transplantation after conditioning with fludarabine and melphalan

Hematopoietic stem cell transplantation may be used to induce a graft-versus-tumor effect against a range of malignancies. Pretransplantation conditioning regimens vary considerably in their degree of myelosuppression and immunosuppression, which may result in marked differences in the rate of T-cell engraftment and, as a consequence, the onset and severity of graft-versus-host disease (GVHD). We have examined the development of T-cell chimerism and the onset of GVHD following fludarabine and melphalan conditioning in 39 patients undergoing stem cell allografts from matched-sibling donors. Cyclosporin and short-course methotrexate were used as GVHD prophylaxis. Fatal regimen-related toxicity occurred in 4 patients. Rapid T-cell engraftment was found in all but 1 of the patients assessed, with more than 90% donor T-cell chimerism at 1 month posttransplantation. Of the evaluable patients, 43% developed grade 2-4 acute GVHD and 87% developed chronic GVHD (70% extensive). Overall, the combination of fludarabine and melphalan is intensely immunosuppressive, leads to rapid T-cell engraftment and results in substantial toxicity and GVHD, particularly in heavily pretreated patients.

Development of reduced-intensity hematopoietic stem cell transplantation in the National Cancer Center Hospital, Japan

Reduced-intensity hematopoietic stem cell transplantation (RIST) is a new approach of stem cell transplantation, which has shown promising features as reported in multiple phase I and II studies. Elderly patients, who are not eligible for conventional myeloablative hematopoietic stem cell transplantation (HSCT), are now treatable with RIST. It has also reduced regimen-related toxicity and provided better prognosis in short-term follow-up than that of conventional HSCT. Favorable results have been reported particularly in hematological malignancies, such as chronic myelocytic leukemia and malignant lymphoma. Among solid tumors, metastatic renal cell carcinoma was found to respond well to RIST. Clinical studies are currently being conducted to evaluate the efficacy of RIST in other types of solid tumors. However, the mechanism of graft-versus-host disease and graft-versus-tumor remains unclear. More knowledge on the mechanism is crucial to enhance antitumor effect and to further improve the prognosis.

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.

Reduced-intensity allogeneic hematopoietic cell transplantation: Graft versus tumor effects with decreased toxicity

The potentially curative role of allogeneic hematopoietic cell transplantation (HCT) in neoplastic and non-neoplastic diseases is offset by the substantial risks of morbidity and mortality from complications of the intensive myeloablative and immunosuppressive preparative regimen. These regimen-related toxicities have restricted allogeneic HCT to young, otherwise healthy individuals without comorbid diseases. Pediatric patients undergoing conventional allogeneic HCT have lower procedure-related mortality but are at risk for non-fatal late effects of the high-dose pretransplant chemoradiotherapy, such as growth retardation, sterility and other endocrine dysfunction. Evaluation of reduced-intensity preparative regimens is the major focus of current clinical research in allogeneic HCT. Reduced-intensity HCT (RI-HCT) relies on the use of immunosuppressive but non-myeloablative agents that allow engraftment of donor cells, which provide adoptive allogeneic cellular immunotherapy and graft versus tumor (GVT) effects, with decreased regimen-related toxicities. Although the experience with RI-HCT in pediatric patients is very limited at this time, results in adults indicate that attenuated-dose preparative regimens allow older patients and those with organ dysfunction to undergo successful allogeneic HCT with acceptable morbidity and mortality. In adults, the potency of the allogeneic GVT effect varies among neoplastic diseases, with better results observed in patients with indolent hematological malignancies or renal cell carcinoma. The effectiveness of RI-HCT as treatment for children with hemoglobinopathies, chronic granulomatous disease and cellular immunodeficiencies is encouraging, and the role of reduced-intensity preparative regimens for allogeneic HCT in pediatric malignancies is under investigation.

Follow-up of patients with progressive multiple myeloma undergoing allografts after reduced-intensity conditioning

Allogeneic stem cell transplantation (allo-SCT) after reduced-intensity conditioning was evaluated in 22 patients (median age 53, range 36-66 years) with multiple myeloma with progression after an autologous SCT. Seven patients received a transplant from a human leucocyte antigen (HLA)-identical sibling and 15 patients (68%) from an unrelated donor [including 3/22 (14%) from a HLA-mismatched unrelated donor]. Graft-versus-host disease (GVHD) prophylaxis consisted of serotherapy with antithymocyte globulin (ATG) and cyclosporine (CSA) (n = 12) or CSA plus mycophenolate mofetil (n = 10). Despite of heavy pretreatment, the transplant-related mortality (TRM) for all grafted patients was acceptable at 5/22 patients (23%). Seven of 21 patients (33%) that were evaluated developed grade II GVHD and one (5%) patient developed grade III/IV acute GVHD. Seven patients developed chronic GVHD (cGVHD), but only one was extensive. Eleven patients died of progressive disease within a median of 7 months (2-19 months) post transplant. Thirteen of all 22 patients (59%) achieved a partial or complete remission with six of these 13 patients (46%) remaining event free at a median of 24 months (range 8-36 months) post allografting. Estimated 2 year overall and event-free survival was, respectively, 25.5% and 22.0% for the whole patient group, and 62.5% and 57.1% for patients with chemosensitive disease. Chemorefractory disease prior to allogeneic stem cell transplantation (P = 0.0182) and absence of cGVHD (P = 0.069) were associated with shorter event-free survival. Thus long-term disease control can be achieved, but is restricted to patients responding to prior salvage chemotherapy.

Long-term results favor allogeneic over autologous hematopoietic stem cell transplantation in patients with refractory or recurrent indolent non-Hodgkin's lymphoma

BACKGROUND

The aim of this study was to compare the outcomes of high-dose therapy (HDT) and allogeneic versus autologous hematopoietic stem cell transplantation (SCT) in patients with refractory or recurrent indolent non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

From January 1991 to March 2000, 112 patients underwent HDT followed by either autologous (68 patients) or allogeneic (44 patients) SCT for refractory or recurrent indolent NHL. Prior conventional chemotherapy had failed in all patients.

RESULTS

The two groups were similar with respect to age at transplantation, gender, histological subtypes, number of chemotherapy regimens received before transplantation and International Prognostic Index scores. The median time from diagnosis to transplantation was longer in the autologous than in the allogeneic SCT group (46 versus 27 months, P = 0.002). In the allogeneic SCT group the median follow-up time was 53 months (range 21-113), and the overall survival (OS) and disease-free survival (DFS) rates were 49% and 45%, respectively. After a median follow-up time of 71 months (range 22-109), in the autologous SCT group, the OS and DFS rates were 34% and 17%, respectively. Patients who underwent autologous SCT were more likely to have chemosensitive disease (P <0.001) and were more likely to be in complete remission at the time of transplantation (P = 0.001) than those who underwent allogeneic SCT. However, the probability of disease progression was significantly higher in the autologous SCT group than in the allogeneic SCT group (74% versus 19%, P = 0.003).

CONCLUSIONS

Patients who undergo HDT with allogeneic SCT for refractory or recurrent indolent NHL have lower relapse rates but higher treatment-related mortality rates than patients who undergo autologous SCT. However, with the development of non-myeloablative preparative regimens, which can decrease treatment-related mortality, patients with recurrent indolent NHL should be considered for controlled trials of allogeneic transplantation if they have a human leukocyte antigen-identical donor.

Transformed lymphoma: an Achilles' heel of non-Hodgkin's lymphoma

Transformed lymphoma has a reported incidence of 10-70% among patients with follicular lymphoma. Interpreting the wide-ranging estimates for incidence, survival, and effects of interventions from various studies is complicated by the use of different definitions of lymphoma transformation. Problems in defining histologic transformation will be addressed in this review. To date, there are no reliable markers of risk for transformation or factors predictive of survival. The prognosis for transformed lymphoma is generally poor, with most patients surviving only a few months, though some with limited disease that is chemosensitive may experience prolonged survival. Immunotherapy, particularly monoclonal antibodies and radioimmunoconjugates, holds promise but more experience is necessary. Approximately 200 patients are included in published series of autologous transplantation; of these, one-third remain disease free at 5 years, not dissimilar to reported outcomes for nontransformed disease. However, the treatment-related mortality is higher than in nontransformed disease, and there is a significant incidence of post-transplant myelodysplastic syndrome. The role of allogeneic transplant has yet to be pursued, but should be explored for its potential for a graft-versus-lymphoma effect. Advances in microarray gene analysis and biology may facilitate the understanding of mechanisms of transformation, development of a prognostic index and creation of tailored therapy.

Reduced-intensity rituximab-BEAM-CAMPATH allogeneic haematopoietic stem cell transplantation for follicular lymphoma is feasible and induces durable molecular remissions

The indolent non-Hodgkin's lymphomas are theoretically curable through allogeneic haematopoietic stem cell transplantation (allo-HSCT). The applicability of standard conditioning allo-HSCT is, however, restricted by its toxicity. Recently, reduced-intensity conditioning regimens have demonstrated efficacy with significantly reduced early morbidity and mortality. We examined the safety and efficacy of rituximab-BEAM-CAMPATH as reduced-intensity conditioning for allo-HSCT in follicular lymphomas. Minimal residual disease was assessed by polymerase chain reaction (PCR) for bcl-2/IgH translocations, and chimerism by X,Y-FISH or PCR amplification of short tandem repeat sequences. At a median follow-up of 521 days (371-719), four of five patients were alive and three were in complete molecular remission. Three patients required pre-emptive treatment for CMV reactivation. One succumbed to a perforated viscus and one had slowly progressive disease. A graft-versus-lymphoma effect was demonstrable and quantitative PCR for bcl-2/IgH may allow better accuracy in scheduling post-allograft rituximab and/or donor lymphocyte infusions. Although follow-up is short, reduced-intensity allo-HSCT with BEAM-CAMPATH conditioning appears to be safe, effective in inducing a molecular remission and is potentially curative. Further recruitment and much longer follow-up will be necessary to determine if this impacts favourably upon disease-free and overall survival.

Impact of graft-versus-host disease in reduced-intensity stem cell transplantation (RIST) for patients with haematological malignancies

To clarify the impact of graft-versus-host disease (GVHD) on the outcome of reduced-intensity stem cell transplantation (RIST), 40 patients who received RIST were compared with those who received conventional stem cell transplantation (CST). RIST regimens consisted of either cladribine (0.11 mg/kg/d x 6, n = 13) or fludarabine (30 mg/m(2)/d x 6, n = 27) with busulphan (BU, 4 mg/kg/d orally x 2), with or without antithymocyte globulin (ATG). CST regimens were either cyclophosphamide/total body irradiation (CY/TBI, n = 23), BU/CY (n = 19) or others (n = 6). The RIST group contained more patients who were at high risk of transplant-related mortality, including older patients, while the two groups contained the same percentages of patients at high risk of relapse. There were no differences between these groups in the incidences of acute (grade II-IV, 31.6% RIST vs 33.3% CST, P = 0.6742) and chronic GVHD (56.2%vs 64.1%, P = 0.8512), relapse rate (15.0%vs 18.8%, P = 0.6642), or overall (69.3%vs 65.6%, P = 0.4817) and progression-free survival (64.7%vs 63.8%, P = 0.6920) at d 500. Multivariate analysis of progression-free survival identified only grade III-IV acute GVHD and relapse risk dose as adverse risk factors. Although GVHD is a major threat in RIST, appropriate induction of GVHD may be associated with anti-tumour activity in RIST comparable to that of CST.

Posttransplantation thrombotic thrombocytopenic purpura: a single-center experience and a contemporary review

OBJECTIVE

To assess the activity of von Willebrand factor-cleaving protease (vWF-CP) in patients with thrombotic thrombocytopenic purpura (TTP) complicating bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT).

PATIENTS AND METHODS

From March 1, 1999, to June 30, 2001, allogeneic and autologous hematopoietic stem cell transplantation was performed in 118 and 400 patients, respectively. We reviewed risk factors for development of posttransplantation TTP and measured vWF-CP activity during active TTP in 10 recipients.

RESULTS

The incidence of TTP after allogeneic and autologous transplantation was 6.8% (8/118) and 0.25% (1/400), respectively. Among the allogeneic transplant recipients, the incidence of TTP after nonmyeloablative (NMA) PBSCT, matched unrelated donor BMT, and sibling BMT or PBSCT was 15.4% (2/13), 11.8% (2/17), and 4.5% (4/88), respectively. Of the 10 patients with TTP, 9 (90%) had received extensive prior therapy, including autologous transplantation in both NMA recipients. Acute graft-vs-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate in most affected patients. The vWF antigen level was elevated in all patients, and no patients showed evidence of vWF-CP deficiency. During active TTP, 6 patients had grade II-IV acute GVHD, 1 had extensive chronic GVHD, and 4 had cytomegalovirus viremia. Risk factor analysis for development of TTP showed that transplant type (NMA and matched unrelated donor) and source of stem cells (bone marrow vs peripheral blood stem cell) were significant.

CONCLUSIONS

Posttransplantation TTP was not found to be associated with severe vWF-CP deficiency. The elevated levels of vWF antigen are consistent with diffuse endothelial injury likely because of multiple interacting factors such as extensive prior therapy, GVHD, cyclosporine, and reactivation of cytomegalovirus. The disorder appears to be more frequent among patients with, or at risk for, acute GVHD, suggesting a possible role in the pathogenesis. Nonmyeloablative transplantation does not appear to confer a lesser risk, possibly for these reasons.

Long-term follow-up of patients with CLL treated with allogeneic hematopoietic transplantation

BACKGROUND

We investigated the long-term outcome of allogeneic stem-cell transplantation after myeloablative conditioning regimen as treatment for patients with chronic lymphocytic leukemia.

METHODS

Patients were eligible for our study if they were refractory or failed a prior response to fludarabine. The conditioning regimen consisted of high-dose CY 60 mg/kg daily for 2 days and fractionated TBI. One patient received BEAM because of prior radiation. GvHD prophylaxis consisted of CYA or tacrolimus and MTX in the majority of patients.

RESULTS

Twenty eight patients were treated. nineteen had disease that was refractory to fludarabine. The median number of prior chemotherapy regimens per patient was 3. Twenty had HLA-identical donors and one had a one-Ag mismatched sibling donor. Seven patients had a matched unrelated transplant. The median follow-up time for the surviving patients was 66 months. By univariate analysis, chemosensitivity was the only factor that predicted a better outcome. For the chemosensitive patients, the overall survival was 78%, compared with 31% for those with refractory disease (P = 0.05). Progression-free survival at 5 years was 78% for the chemosensitive and 26% for those who were refractory to conventional chemotherapy at the time of transplantation (P = 0.03). Three patients (11%) died within 100 days of transplant. The actuarial risk of acute Grade II-IV GvHD was 49%. Only one patient developed acute Grade III GvHD.

CONCLUSION

Allogeneic transplantation is probably curative for a subset of patients with chronic lymphocytic leukemia. Patients should be considered for clinical trials involving allogeneic transplantation at an earlier stage prior acquiring chemorefractoriness.

The choice of allogeneic or autologous hematopoietic transplantation for NHL

NHL constitutes the sixth most common malignancy diagnosed in the USA every year, accounting for approximately 24,400 deaths. Although a subset of patients can be cured with chemotherapy or radiation therapy, the outlook is generally poor for patients with refractory or recurrent disease. High-dose therapy supported by both autologous and allogeneic transplantation has been widely studied in this group of patients. Autologous transplantation may be considered standard therapy for patients with diffuse large-cell NHL in chemotherapy-sensitive relapse. Selected categories of patients with other histologic subtypes may also benefit from this strategy. Allogeneic transplantation using high-dose myeloablative conditioning regimen is an effective, yet hazardous approach. A GvL effect leads to a lower rate of disease recurrence than occurs with autologous transplants, but this benefit is offset by higher risk of treatment related mortality. The recent use of less toxic non-myeloablative conditioning regimens for allogeneic transplantation has reduced the risk of transplant-related mortality, allowing this approach even in older or medically infirm patients. Nonablative allogeneic transplants are a promising strategy, particularly for patients with indolent lymphoid malignancies.

Graft-versus-host disease can be separated from graft-versus-lymphoma effects by control of lymphocyte trafficking with FTY720

Graft-versus-host disease (GvHD) mediated by donor T cells recognizing host alloantigens is associated with beneficial graft-versus-tumor effects in recipients of allogeneic hematopoietic cell transplants. Since leukemias and lymphomas reside largely within the lymphohematopoietic system, we have proposed that the desired graft-versus-leukemia or graft-versus-lymphoma effect can be separated from the complication of GvHD by confinement of the graft-versus-host alloresponse to the lymphohematopoietic tissues. Since the new sphingosine-1-phosphate receptor agonist immunosuppressive drug FTY720 leads to trapping of T cells in secondary lymphoid tissues, we evaluated the possibility that this drug could diminish GvHD, a disease involving epithelial target tissues, while permitting a beneficial alloresponse to take place within the lymphohematopoietic system, leading to graft-versus-lymphoma effects. We demonstrate here that FTY720 markedly reduces GvHD in a clinically relevant, haploidentical strain combination, while permitting antitumor effects against a T cell lymphoma of unshared host MHC haplotype to proceed unhindered. These results establish a potential new immunotherapeutic approach to separating graft-versus-leukemia effects from GvHD.

High-dose cyclophosphamide, BCNU, and VP-16 (CBV) conditioning before allogeneic stem cell transplantation for patients with non-Hodgkin's lymphoma

Allogeneic stem cell transplantation (SCT) has been shown to be a curative therapy for some patients with non-Hodgkin's lymphoma (NHL). Total-body irradiation and high-dose cyclophosphamide combinations are the most established conditioning regimens used in this setting. We examined the efficacy and toxicity of cyclophosphamide, BCNU, and VP-16 (CBV) as a suitable chemotherapy-only regimen for NHL patients. In total, 18 patients, median age 42 years, with NHL were treated with CBV followed by allotransplant. Patients had received a median of two prior chemotherapy regimens. Median times to neutrophil and platelet recovery were 19 and 15 days, respectively. Interstitial pneumonitis occurred in one patient. There have been four relapses after a median follow-up of 39 months. Overall, there were four deaths, one because of relapse. The 2-year estimates of relapse-free and overall survival are 56 and 76%, respectively. CBV is a safe and an effective alternative to TBI-containing regimens before allogeneic SCT for NHL.

Allogeneic stem cell transplantation after reduced-intensity conditioning in lymphoid malignancies

Allogeneic stem cell transplantation (allo-SCT) is an effective therapeutic option for a wide range of hematological malignancies. The toxicity of the conditioning regimen and graft-versus-host disease (GVHD) occurring after the infusion of the graft remain the most important factors leading to high morbidity and mortality. Reduced-intensity conditioning regimens have recently been developed in an effort to reduce the toxicity associated with conventional allo-SCT while preserving the curative potential of the graft-versus-tumor (GVT) effect. Most patients with lymphoproliferative disorders are not ideal candidates for allo-SCT due to higher age at diagnosis, which together with the advanced stage of disease at the time of transplantation can lead to a high transplant-related mortality (TRM). Preliminary experience indicates that reduced-intensity allo-SCT is feasible in such patients. The immediate TRM is low in comparison with conventional procedures and overall results seem promising, thus indicating the existence of a GVT effect. Nevertheless, all series are still low in numbers and follow-up is too short to draw definitive conclusions. Acute and chronic GVHD remain a significant problem with incidences comparable to the conventional setting in some series. Thus, therapeutic strategies must be sought to decrease GVHD without abrogating the GVT effect.

Review of "minitransplantation": nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation (HSCT) have been developed over the past few years as important alternatives to conventional myeloablative conditioning regimens for older or medically unfit patients with hematologic malignancies, as well as for patients with certain nonmalignant hematologic diseases or renal cell cancer. This review summarizes the biological background, current clinical applications, and indications for this novel treatment approach for treating hematologic malignancies. Historically, allogeneic HSCT has been based on the use of cytotoxic and myeloablative chemotherapy and radiotherapy conditioning regimens that are intended both to eradicate malignancy and to eliminate host hematopoiesis and immune cells. Such a regimen was followed by the infusion of histocompatible donor marrow or peripheral blood stem cells to rescue hematopoiesis. For older patients or for those who had previously been treated with intensive chemotherapy or radiotherapy, the toxicity of myeloablative conditioning was prohibitive. Although most hematologic malignancies occur in older patients, these patients had not been previously eligible for the potentially curative therapy offered by allogeneic HSCT. Based in large part on preclinical studies with the dog model of HSCT and on an improved understanding of the mechanisms for controlling immune modulation, successful development of nonmyeloablative conditioning regimens for clinical use has occurred. Clear evidence of a therapeutic graft-versus-tumor effect mediated by allogeneic T-cells prompted an exploration for HSCT regimens that rely solely on nonmyeloablative immunosuppression to facilitate allogeneic engraftment. In lieu of intensive chemoradiotherapy before transplantation, engrafted donor T-cells are used to accomplish the task of eradicating the host's malignant cells. We review the updated results of an ongoing multicenter study to investigate the safety and efficacy of nonmyeloablative HSCT using a regimen of 2 Gy total body irradiation in patients with advanced hematologic malignancies who were ineligible for conventional myeloablative conditioning. In addition, we review the results of reduced-intensity HSCT trials from other transplantation centers.

Is there a role for reduced-intensity haematopoietic stem cell transplantation for indolent non-Hodgkin's lymphoma?

The therapeutic options for the indolent non-Hodgkin's lymphomas have evolved significantly over the years. However, at present, allogeneic haematopoietic stem cell transplantation (HSCT), despite its significant transplant associated complications, is still the only option which may be delivered with curative potential. The debut of reduced-intensity conditioning regimens has extended the applicability of allogeneic transplants to groups of patients ineligible for conventional myeloablative allografts. However, there are still substantial hurdles to overcome, namely that of relapse, graft-versus-host disease and infection. Whilst follow-up is still relatively limited for a disease group with a median survival of up to 10 years, early results are extremely encouraging and further studies are warranted.

Clinical developments in reduced intensity haematopoietic stem cell transplantation

Reduced intensity conditioning regimens prior to allogeneic haematopoietic stem cell transplantation (HSCT) were first described in the 1970s, and have developed rapidly over the past few years to become an important consideration as immunological therapy for patients with haematological and selected solid organ malignancies. This is especially the case for patients considered ineligible for conventional allogeneic HSCT due to age or medical contraindications. With the development of minimally toxic conditioning regimens, additional potential applications include the provision of normal haematopoietic repopulating cells to patients who have an inherited gene defect such as an haemoglobinopathy or an inborn error of metabolism. Intensive investigation in stem cell research promises to provide dramatic new insights into human biology, paving the way for new therapeutic approaches to malignant and inherited disorders.