Allogeneic stem cell transplantation with fludarabine-based, less intensive conditioning regimens as adoptive immunotherapy in advanced Hodgkin's disease

Haploidentical Stem Cell Transplantation With Post-Transplantation Cyclophosphamide for Aggressive Lymphomas: How Far Have We Come and Where Are We Going?

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplant cyclophosphamide (PTCy) offers universal donor availability and can potentially cure relapsed or primary refractory Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). However, a conditioning regimen intensity that balances the graft-versus-lymphoma (GvL) effect with regimen-related toxicities (RRTs) has not yet been optimized. Limited data exist on the management of relapse, which is common post-transplant. Few prospective or randomized control trials have been conducted on lymphoma patients undergoing haplo-HSCT. Therefore, the current review aims to summarize published retrospective data in the field to help guide clinical decision making for high-risk patients. Retrospective studies in the field are characterized by variability in patient population and sample sizes, eligibility criteria, number of prior treatments (e.g., chemotherapy, radiation therapy, and autologous transplant), graft source (bone marrow or peripheral blood), as well as choice and intensity of the conditioning regimen (non-myeloablative, reduced intensity, or myeloablative). Nonetheless, common themes that emerge from the literature include: 1) Enhanced donor availability and selection with haplo-HSCT with success in heterogeneous patient populations; 2) Outcomes that are comparable if not superior to matched related (MRD) or unrelated (MUD) donor transplants; 3) The benefit of PTCy for reducing incidence of relapse and chronic graft-versus-host disease (GvHD); 4) Presence of co-morbidities leading to poorer transplant-related outcomes; and 5) The need for novel approaches to address disease relapse, particularly for patients with active disease at the time of transplant. Excellent transplant-related outcomes with haplo-HSCT with PTCy have been seen for HL and NHL based on retrospective data. Further studies are needed to determine integration with advanced cellular therapy techniques, such as chimeric antigen receptor (CAR) T-cell, antibody drug conjugates, and checkpoint inhibitors. Graft manipulation may be another avenue for future research.

Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic hematopoietic stem cell transplantation for acute leukemia patients: a single center experience

Due to the high transplant related morbidity and mortality (TRM), relatively younger acute leukemia patients that have a good performance status and no comorbidity are eligible for myeloablative conditioning (MAC) followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The outcomes of 84 consecutive adult patients with ALL (n=38) or AML (n=46) who underwent allo-HSCT from their HLA-identical siblings were evaluated retrospectively. The median age at transplantation was 34 (17-58 years) for the whole patient population. Of these, 24 patients received a MAC and 60 patients received a fludarabine-based reduced intensity conditioning regimen (RIC). After a median follow-up of 32 months (range, 1-119), for the entire group, the 3-year estimated overall survival (OS) was 57.5% and the disease-free survival (DFS) was 51.5%. The OS for ALL and AML patients were 53.9% vs 62.1%: and DFS were 50.5% and 53.4%, respectively. The 3-year estimated OS for RIC and MAC patients were 63.2% and 41.7%; and DFS were 57.1% and 34.7%, respectively. In ALL patients, conditioning regimens (RIC vs MAC) led to similar OS and DFS; however, in AML patients both OS (70.1% vs 21.4%) and DFS (59.3% vs 42.9%) were found to be higher in RIC patients compared to MAC recipients. Overall, the TRM at day 100 was 1.7% and has increased up to 5.1% at 1st year. In multivariate analysis, the diagnosis (p=0.03) and RIC regimen (p=0.027) were the prognostic variables for prolonged OS in all patients; and RIC regimen (p=0.031) was the only prognostic factor for prolonged OS in AML patients. The first complete remission (CR1) was correlated with a prolonged DFS as an independent variable for all patients (p=0.09). Eleven of the RIC patients (18.3%) and 6 of the MAC patients (25%) developed acute graft-versus-host disease (GvHD). Seventeen of the RIC patients (33.3%) and 4 of the MAC patients (16.7%) developed chronic GvHD. In conclusion, RIC conditioning regimens may provide a longer OS and DFS, especially in patients with AML who are in first CR, not eligible for MAC conditioning.

Fifty years of melphalan use in hematopoietic stem cell transplantation

Melphalan remains the most widely used agent in preparative regimens for hematopoietic stem cell transplantation (SCT). From its initial discovery more than 50 years ago, it has been gradually incorporated in the conditioning regimens for both autologous and allogeneic transplantations because of its myeloablative properties and broad antitumor effects as a DNA alkylating agent. Melphalan remains the mainstay conditioning for multiple myeloma and lymphomas, and it has been used successfully in preparative regimens of a variety of other hematological and nonhematological malignancies. The addition of newer agents to conditioning, such as bortezomib or lenalidomide for myeloma or clofarabine for myeloid malignancies, may improve antitumor effects for transplantation, whereas melphalan in combination with alemtuzumab may represent a backbone for future cellular therapy because of reliable engraftment and low toxicity profile. This review summarizes the development and the current use of this remarkable drug in hematopoietic SCT.

Allogeneic hematopoietic stem cell transplantation in children and adolescents with recurrent and refractory Hodgkin lymphoma: an analysis of the European Group for Blood and Marrow Transplantation

Ninety-one children and adolescents 18 years or younger after allogeneic hematopoietic stem cell transplantation (HSCT) for relapsed or refractory Hodgkin lymphoma (HL) were analyzed. Fifty-one patients received reduced intensity conditioning (RIC); 40 patients received myeloablative conditioning (MAC). Nonrelapse mortality (NRM) at 1 year was 21% (+/- 4%), with comparable results after RIC or MAC. Probabilities of relapse at 2 and 5 years were 36% (+/- 5%) and 44% (+/- 6%), respectively. RIC was associated with an increased relapse risk compared with MAC; most apparent beginning 9 months after HSCT (P = .01). Progression-free survival (PFS) was 40% (+/- 6%) and 30% (+/- 6%) and overall survival (OS) was 54% (+/- 6%) and 45% (+/- 6%) at 2 and 5 years, respectively. Disease status at HSCT was predictive of PFS in multivariate analysis (P < .001). Beyond 9 months, PFS after RIC was lower compared with MAC (P = .02). Graft-versus-host disease did not affect relapse rate and PFS. In conclusion, children and adolescents with recurring HL show reasonable results with allogeneic HSCT. Especially patients allografted in recent years with good performance status and chemosensitive disease show highly encouraging results (PFS: 60% +/- 27%, OS: 83% +/- 15% at 3 years). Because relapse remains the major cause of treatment failure, additional efforts to improve disease control are necessary.

Optimal treatment for relapsing patients with Hodgkin lymphoma

Relapsed or refractory classical Hodgkin lymphoma (HL) remains a therapeutic challenge. Patients with relapsed HL should be identified according to their prognostic factors at relapse (duration of remission and extranodal disease or stage). Patients with refractory disease, defined as progression during induction treatment or within 90 days after the end of treatment, have the worst prognosis. Following non-crossresistant salvage chemotherapy to achieve cytoreduction, high-dose therapy (HDT) and autologous stem cell transplantation has been shown to be better than conventional-dose chemotherapy for first-relapse/refractory HL. For patients with very unfavorable relapse or primary refractory HL, outcome remains poor with HDT. For these patients, the role of tandem HDT or allogeneic stem cell transplantation will be discussed. In this setting, novel investigational treatments will be presented.

Haematopoietic SCT for children and adolescents with relapsed and refractory Hodgkin's lymphoma

Despite the generally excellent prognosis of children and adolescents with Hodgkin's lymphoma (HL), approximately 15% of patients relapse. Salvage therapy options include further chemo-radiotherapy and autologous or allogeneic haematopoietic SCT (HSCT). Autologous HSCT following high-dose chemotherapy, the standard treatment for adult patients with relapsed HL, is also effective in paediatric patients, but randomized trials showing its superiority to conventional therapy are lacking. Although patients with late relapse (>12 months after completion of therapy) may be cured with conventional therapy, those with progressive disease or early relapse (3-12 months) are considered candidates for autologous HSCT. According to patient selection criteria, overall and disease-free survival rates after autologous HSCT are 43-95% and 31-70%, respectively. Short time to relapse and refractory disease at the time of autologous HSCT remain the most important risk factors. Data on allogeneic HSCT in children with HL are scarce. Broader use has been hampered for a long time mainly by high non-relapse mortality, offsetting the advantage of a graft-vs-lymphoma effect. Data suggest that young patients with recurring disease following autologous HSCT, as well as some patients with multiple relapses and selected patients with refractory lymphoma, might benefit from allogeneic HSCT, but relapse remains the major challenge.

Fludarabine in the treatment of chronic lymphocytic leukemia: a review

Fludarabine (FAMP) is the most effective and most extensively studied purine analog in indolent B-cell malignancies. Its use is indicated for first-and second-line treatment of B-cell chronic lymphocytic leukemia (B-CLL). FAMP as a single agent has produced superior response rates and progression-free survival than standard therapy with chlorambucil and alkylator-based regimen. Efficacy of FAMP may be increased by combining this purine analog with other chemotherapeutic and non-chemotherapeutic agents. FAMP and cyclophosphamide combination (FC) has shown promising results with higher overall response and complete response rates than FAMP in monotherapy, although no difference has been detected in survival. Quality of response and eradication of minimal residual disease (MRD) have been reported to be associated with prolonged survival. Eradication of MRD has been achieved by combining FC with mitoxantrone or monoclonal antibody including alemtuzumab or rituximab or both. FAMP has been widely used in non-myeloablative conditioning regimens, often combined with a variety of other cytotoxic agents, with the aim of inducing enough immunosuppression to allow successful engraftment and to exert some pretransplant anti-tumor activity. The current paper provides an overview of use of FAMP as a single agent or as a cornerstone of different therapeutic strategies for treatment of B-CLL patients.

Comparison of outcomes of HLA-matched related, unrelated, or HLA-haploidentical related hematopoietic cell transplantation following nonmyeloablative conditioning for relapsed or refractory Hodgkin lymphoma

We compared the outcome of nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) for patients with relapsed or refractory Hodgkin lymphoma (HL) based on donor cell source. Ninety patients with HL were treated with nonmyeloablative conditioning followed by HCT from HLA-matched related, n=38, unrelated, n=24, or HLA-haploidentical related, n=28 donors. Patients were heavily pretreated with a median of 5 regimens and most patients had failed autologous HCT (92%) and local radiation therapy (83%). With a median follow-up of 25 months, 2-year overall survivals, progression-free survivals (OS)/(PFS), and incidences of relapsed/progressive disease were 53%, 23%, and 56% (HLA-matched related), 58%, 29%, and 63% (unrelated), and 58%, 51%, and 40% (HLA-haploidentical related), respectively. Nonrelapse mortality (NRM) was significantly lower for HLA-haploidentical related (P=.02) recipients compared to HLA-matched related recipients. There were also significantly decreased risks of relapse for HLA-haploidentical related recipients compared to HLA-matched related (P=.01) and unrelated (P=.03) recipients. The incidences of acute grades III-IV and extensive chronic graft-versus-host disease (aGVHD, cGVHD) were 16%/50% (HLA-matched related), 8%/63% (unrelated), and 11%/35% (HLA-haploidentical related). These data suggested that salvage allogeneic HCT using nonmyeloablative conditioning provided antitumor activity in patients with advanced HL; however, disease relapse/progression continued to be major problems. Importantly, alternative donor stem cell sources are a viable option.

Management of Hodgkin lymphoma in relapse after autologous stem cell transplant

Recurrence of Hodgkin lymphoma (HL) occurs in about 50% of patients after autologous stem cell transplantation (ASCT), usually within the first year, and represents a significant therapeutic challenge. The natural history of recurrent HL in this setting may range from a rapidly progressive to a more indolent course. Patients in this setting are often young, without comorbidities and able to tolerate additional therapies: expectations are often still high. The approach to treatment depends on clinical variables (time to relapse, perceived sensitivity to additional cytotoxic therapy, disease stage), prior history of radiation therapy, the availability of an HLA-identical donor, and the availability of new agents via clinical trials. Although very few of these patients can be cured, results from reported series, albeit often small and sometimes with relatively short follow-up, document that excellent disease control can be achieved with radiation, single or multiagent chemotherapy, and reduced-intensity allogeneic transplantation. The results of these approaches will be reviewed, and a treatment algorithm incorporating the use of standard or investigational agents or approaches will be discussed.

Reduced-intensity conditioning for allogeneic haematopoietic stem cell transplantation in relapsed and refractory Hodgkin lymphoma: impact of alemtuzumab and donor lymphocyte infusions on long-term outcomes

The introduction of reduced-intensity conditioning (RIC) has enabled the role of allogeneic transplantation to be re-evaluated in Hodgkin lymphoma (HL). While T-cell depletion reduces graft-versus-host disease (GvHD), it potentially abrogates graft-versus-tumour activity and increases infective complications. We compared the results in 67 sibling donor transplantations following RIC in multiply relapsed patients from two national phase II studies conditioned with fludarabine/melphalan. One used cyclosporine/alemtuzumab (MF-A, n = 31), the other used cyclosporine/methotrexate (MF, n = 36) as GvHD prophylaxis. There was a small excess of chemorefractory cases in the MF cohort (P = NS). MF-A resulted in significantly lower incidences of non-relapse mortality, acute and chronic GvHD, but no significant excess of relapse/progression. Post donor lymphocyte infusion (DLI) disease responses occurred in 8/14 (57%) and 6/11 (55%) patients in the MF-A and MF groups, respectively. Current progression-free survival (CPFS) was superior with MF-A (univariate analysis), with durable responses to DLI contributing to the favourable outcome (43% vs. 25%, P = 0.0356). Disease status at transplantation significantly influenced overall survival (P = 0.0038) and CPFS (P = 0.0014), retaining significance in multivariate analyses, which demonstrated a trend towards improved CPFS with T-cell depletion (P = 0.0939). These data suggest that alemtuzumab significantly reduced GvHD without resulting in a deleterious impact on survival outcomes following RIC in HL, and that durable responses to DLI may be more common following the inclusion of alemtuzumab in the conditioning protocol.

Hyperacute GVHD: risk factors, outcomes, and clinical implications

Acute graft-versus-host disease (GVHD) is a major limiting factor in allogeneic hematopoietic stem cell transplantation (HSCT), and the timing of acute GVHD may affect patient outcomes. We evaluated the incidence, risk factors, clinical manifestations, and outcomes of hyperacute GVHD, defined as that occurring within 14 days after transplantation, among 809 consecutive HSCTs at the University of Texas M.D. Anderson Cancer Center. Of 265 patients with grade II-IV acute GVHD, 27% had biopsy-proven hyperacute GVHD. Skin involvement was significantly more common (88% versus 44%) and more severe (stage III-IV, 88% versus 66%) in the hyperacute group compared with acute GVHD diagnosed after day 14. On multivariate analysis, significant risk factors for hyperacute GVHD included a mismatched related or matched unrelated donor, a myeloablative conditioning regimen, more than 5 prior chemotherapy regimens, and donor-recipient sex mismatch. Hyperacute GVHD was associated with a significantly lower response rate to first-line therapy and a higher rate of nonrelapse mortality in patients with a mismatched related or matched unrelated donor graft. In conclusion, hyperacute GVHD accounts for a substantial proportion of grade II-IV acute GVHD after HSCT. Patients at high risk or with a diagnosis of hyperacute GVHD should be included in clinical studies.

Reduced-intensity allogeneic transplantation in patients with refractory or progressive Hodgkin's disease after high-dose chemotherapy and autologous stem cell infusion

BACKGROUND

We analysed the feasibility and efficacy of allogeneic stem cell transplantation (allo-SCT) with reduced-intensity conditioning (RIC) in patients with refractory or progressive Hodgkin's disease (HD) after high-dose chemotherapy (HDCT).

PATIENTS AND METHODS

Fourteen patients with HD received allo-SCT with RIC: eleven patients had a human leucocytes antigen-identical related donor and three a matched unrelated donor. Six had chemoresistant disease and eight had chemosensitive one at the time of transplantation. All patients received a fludarabine-based RIC.

RESULTS

All patients engrafted and full donor chimerism was achieved in all patients. Grade II acute graft-vs.-host disease (GvHD) developed in six of the 14 patients (43%). Chronic GvHD developed in eight of the 13 patients (61%). There was neither early nor late treatment-related mortality (TRM). With a median follow-up of 21 months (range 3-74), 10 of the 14 patients were alive (71%). Estimated overall survival at 1 and 2 yr was 93% and 73%, respectively, for the whole population, 83% and 44% respectively for patients with chemoresistant disease and 100% for those with chemosensitive disease. Estimated progression-free survival at 1 yr was 36%; 62.5% for chemosensitive patients and 0% for those with chemoresistant disease.

CONCLUSIONS

In conclusion, allo-SCT with fludarabine-based RIC is a feasible procedure, without TRM in HD patients relapsed and refractory after HDCT. Even if several questions are still open, this approach should proposed for these poor prognosis patients.

Current strategies and new approaches in the treatment of Hodgkin's lymphoma

As a result of continuous improvement in therapeutic options and their verification by large multicenter trials, Hodgkin's lymphoma (HL) has become one of the best curable cancers in adults. Nowadays, about 80-90% of patients in all stages achieve long-term survival. Nevertheless, these good results are threatened by treatment-associated toxicities such as infertility, cardiopulmonary toxicity and secondary malignancies. It is therefore the aim of future trial generations both to maintain excellent treatment results and to minimize late effects. At early stages, ongoing trials ask how many cycles of ABVD-like chemotherapy are necessary and if radiation doses might be further reduced or even omitted in favorable early-stage disease. In advanced stages, new combinations of chemotherapeutic drugs with higher dose densities are tested with or without the application of consolidating radiotherapy. The treatment of patients with relapsed HL depends on previous therapies with radiotherapy, chemotherapy or high-dose chemotherapy followed by autologous stem cell transplantation. For patients with multiple relapses, experimental treatment strategies include antibody- and small-molecule-based regimens. In this review we present current treatment strategies for patients with a first diagnosis of HL and relapsed HL as well as recent experimental therapeutic approaches.

Role of fludarabine in hematological malignancies

Fludarabine is a prodrug that is converted to the free nucleoside 9-beta-D-arabinosyl-2-fluoroadenine (F-ara-A), which enters cells and accumulates mainly as the 5'-triphosphate, F-ara-ATP. F-ara-ATP has multiple mechanisms of action, which are mostly directed toward DNA. Collectively, these actions affect DNA synthesis, which is the major mechanism of F-ara-A-induced cytotoxicity. Secondarily, incorporation into RNA and inhibition of transcription has been shown in cell lines. As a single agent, fludarabine has been effective for indolent leukemia. Biochemical modulation strategies resulted in enhanced accumulation of cytarabine triphosphate and led to the use of fludarabine for the treatment of acute leukemia. The combination of fludarabine with DNA-damaging agents to inhibit DNA repair processes has been highly effective for indolent leukemia and lymphomas. Other strategies have incorporated fludarabine into preparative regimens for nonmyeloablative stem-cell transplantation.

Morphologic examination of sequential bone marrow biopsies after nonmyeloablative stem cell transplantation complements molecular studies of donor engraftment

CONTEXT

Nonmyeloablative stem cell transplantation (NMSCT) is a mode of immunotherapy increasingly employed in treating hematologic, lymphoid, and solid tumors. Patients are monitored principally by molecular analysis of donor engraftment.

OBJECTIVE

To determine the role of morphologic examination of bone marrow after NMSCT.

DESIGN

Seventy-three patients undergoing NMSCT under the Campath 1H (humanized anti-CD52 antibody) protocol were studied. Pretransplant and sequential posttransplant bone marrow specimens were evaluated and the findings were correlated with corresponding engraftment data.

RESULTS

Pretransplant bone marrow specimens from 43% of the patients were involved by disease, and these marrow specimens were significantly more cellular than those that were free of disease. Morphologically detectable disease was still present in day 14 posttransplant marrow specimens in more than one half of these patients, but there was no difference in engraftment in those with or without marrow disease. Early posttransplant marrow in nearly one half of the patients showed myeloid hyperplasia and atypical localization of immature myeloid precursors. Marrow cellularity for the first 2 months after NMSCT was significantly lower in those patients receiving stem cells mismatched at 1 to 3 loci as compared with those who received fully matched grafts (mean cellularity, 38.1% vs 54.1% at day 14). Marrow failure without recurrent disease at 3 to 6 months after transplant was detected by engraftment study in only approximately 15% of cases. Similarly, early recurrence of disease was detected first by morphologic examination in 4 of 13 cases before a decline in donor engraftment occurred.

CONCLUSION

Morphologic examination of bone marrow provides additional information that is complementary to donor engraftment analysis for optimal management after NMSCT.

The graft-versus-lymphoma effect: clinical review and future opportunities

Numerous lines of preclinical and clinical evidence support the existence of a graft-versus-leukemia effect, but less evidence supporting a comparable graft-versus-lymphoma effect exists. We review here current clinical data addressing the graft-versus-lymphoma effect, including comparisons of autologous, syngeneic, and allogeneic transplantation; responses to immunomodulation; and responses to nonmyeloablative stem cell transplantation. Despite several limitations of the data, we believe that there is sufficient evidence suggesting a significant graft-versus-lymphoma effect. In addition, we discuss approaches for clinical management of lymphoma patients, opportunities for mechanistic studies afforded by donor leukocyte infusions and nonmyeloablative transplantation, and suggestions for clinical studies to further define the magnitude and applicability of the graft-versus-lymphoma effect.

Reduced-intensity allogeneic stem cell transplantation in adults and children with malignant and nonmalignant diseases: end of the beginning and future challenges

During the last 10 years, multiple studies using reduced-intensity (RI) conditioning followed by allogeneic stem cell transplantation (AlloSCT) have been reported in adult and, less so, pediatric recipients. RI AlloSCT allegedly eradicates malignant cells through a graft-versus-leukemia/graft-versus-tumor effect provided by alloreactive donor T lymphocytes, natural killer cells, or both. Various studies have clearly demonstrated a graft-versus-leukemia/graft-versus-tumor effect in hematologic malignancies and solid tumors. Acute short-term toxicity, including infection and organ decompensation after myeloablative conditioning therapy, can result in a significant incidence of early transplant-related mortality. More importantly, long-term late effects-including growth retardation, infertility, and secondary malignancies-are major complications after myeloablative conditioning therapy, especially in vulnerable children, who are more susceptible to these complications. Recent results comparing RI conditioning with myeloablative conditioning followed by HLA-matched sibling AlloSCT have demonstrated a significant reduction in use of blood products, risk of infections, transplant-related mortality, length of hospitalization, and feasibility of conditioning therapy in outpatient settings. Despite the success of RI AlloSCT, large prospective randomized multicenter studies are necessary to define the appropriate patient population, optimal conditioning regimens and pretransplantation immunosuppression, role of donor lymphocyte infusions, duration of hospitalization, overall survival, cost-benefit ratio, and differences in long-term effects to evaluate the role of RI AlloSCT more fully. We review the recent experience of RI AlloSCT in adults and children with both malignant and nonmalignant diseases and discuss the challenges for the future.

The role of allogeneic stem-cell transplantation in Hodgkin's disease

The role of allogeneic stem cell transplantation is still controversial. Early results of allogeneic bone marrow transplantation after conventional conditioning indicated high transplant-related mortality (TRM) (> 50%) and disappointing survival (< 20%). The introduction of reduced-intensity conditioning (RIC) prior to transplantation has reduced TRM. Unfortunately graft-vs.-host disease, relapse rates and survival have not substantially changed. Modifications of allogeneic transplantation in patients with Hodgkin's disease should be restricted to prospective trials.

A prognostic model for prolonged event-free survival after autologous or allogeneic blood or marrow transplantation for relapsed and refractory Hodgkin's disease

There are several prognostic models for Hodgkin's disease (HD) patients, but none evaluating patient characteristics at time of blood and marrow transplantation (BMT). We developed a prognostic model for event-free survival (EFS) post-BMT based on HD patient characteristics measured at the time of autologous (auto) or allogeneic (allo) BMT. Between 1/1991 and 12/2001, 64 relapsed or refractory HD patients received an auto (n=46) or allo (n=18) BMT. A multivariate prognostic model was developed measuring time to relapse, progression or death. Median follow-up was 51.7 months; median EFS for auto and allo BMT was 36 and 3 months, respectively (P=0.001). Significant multivariate predictors of shorter EFS were chemotherapy-resistant disease, KPS <90 and > or =3 chemotherapy regimens pre-BMT. Patients with two to three adverse factors had significantly shorter EFS at 2 years (58 vs 11% in auto; 38 vs 0% in allo BMT patients). Despite a selection bias favoring auto BMT, the model was valid in both auto and allo BMT groups. We were able to differentiate patients at high vs low risk for adverse outcomes post-BMT. This prognostic model may prove useful in predicting patient outcomes and identifying high-risk patients for novel treatment strategies. Validation of this model in a larger cohort of patients is warranted.

Clinical evidence of a graft-versus-Hodgkin's-lymphoma effect after reduced-intensity allogeneic transplantation

BACKGROUND

In patients with multiply relapsed Hodgkin's lymphoma allogeneic stem-cell transplantation has been limited by prohibitive non-relapse-related mortality rates and by a lack of definitive evidence for a therapeutic graft-versus-tumour effect. Therefore, we aimed to assess the graft-versus-tumour effect of reduced-intensity allogeneic transplantation.

METHODS

We undertook reduced-intensity transplantation in 49 patients with multiply relapsed Hodgkin's lymphoma, 44 (90%) of whom had progression of disease after previous autologous transplantation (median age 32 years [range 18-51], number of previous treatment courses was five [range 3-8], and time from diagnosis 4.8 years [range 0.6-4.8]). 31 patients had HLA matched donors who were related and 18 had donors who were unrelated. Median follow-up was 967 days (range 102-2232). The primary endpoints were engraftment, toxic effects, non-relapse-related mortality, incidence of graft-versus-host disease (GVHD), and the toxic effects of adjuvant donor-lymphocyte infusion.

FINDINGS

All patients engrafted. Eight of 49 (16%) had grade II-IV acute GVHD and seven (14%) had chronic GVHD before donor-lymphocyte infusion. 16 (33%) patients received donor-lymphocyte infusion from 3 months after transplantation for residual disease or progression. Six (38%) of the 16 developed grade II-IV acute GVHD and five developed chronic GVHD. Nine (56%) showed disease responses after infusion (eight complete, one partial). Non-relapse-related mortality was 16.3% at 730 days (7.2% for patients who had related donors vs 34.1% for those with unrelated donors, p=0.0206). Projected 4 year overall and progression-free survival were 55.7% and 39.0%, respectively (62.0% and 41.5% for related donors).

INTERPRETATION

These data show the potential for durable responses in patients who have previously had substantial treatment for Hodgkin's lymphoma. The low non-relapse-related mortality suggests the procedure could be undertaken earlier in the course of the disease.

Reduced-intensity allogeneic stem cell transplantation in relapsed and refractory Hodgkin's disease: low transplant-related mortality and impact of intensity of conditioning regimen

A total of 40 patients with relapsed/refractory Hodgkin's disease (HD) underwent reduced-intensity conditioning (RIC) allogeneic stem cell transplantation (allo-SCT) from an HLA-identical sibling (n=20) or a matched unrelated donor (n=20). The median age was 31 years (range 18-58). Disease status at allo-SCT was refractory relapse (n=14) or sensitive relapse (n=26). The conditioning regimens were fludarabine-cyclophosphamide+/-antithymocyte globulin (n=14), a less intensive regimen, and fludarabine-melphalan (FM) (n=26), a more intensive one. The two groups had similar prognostic factors. The median time to neutrophil recovery (ie absolute neutrophil count >/=500/microl) was 12 days (range 10-24). The median time to platelet recovery (ie platelet count >/=20 000/microl) was 17 days (range 7-132). Day 100 and cumulative (18-month) transplant-related mortalities (TRMs) were 5 and 22%. Twenty-four patients (60%) are alive (14 in complete remission or complete remission, unconfirmed/uncertain) with a median follow-up of 13 months (4-78). In all, 16 patients expired (TRM n=8, disease progression n=8). FM patients had better overall survival (73 vs 39% at 18 months; P=0.03), and a trend towards better progression-free survival (37 vs 21% at 18 months; P=0.2). RIC allo-SCT is feasible in relapsed/refractory HD patients with a low TRM. The intensity of the preparative regimen affects survival.

Cyclosporine and mycophenolate mofetil prophylaxis with fludarabine and melphalan conditioning for unrelated donor transplantation: a prospective study of 22 patients with hematologic malignancies

In an attempt to decrease toxicity in high-risk patients undergoing unrelated donor hematopoietic stem cell transplantation (URD HSCT), we tested a combination of cyclosporine (CSP) and mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis with the reduced-intensity conditioning regimen fludarabine/melphalan (Flu/Mel). A total of 22 adult patients with advanced myeloid (n=15) and lymphoid (n=7) malignancies were treated. All patients received Flu 25 mg/m2 for 5 days and Mel 140 mg/m2, with CSP 3 mg/kg daily and MMF 15 mg/kg three times a day. The median age was 49 years (range 18-66). Durable engraftment was seen in all but one patient with myelofibrosis. The 1-year nonrelapse mortality was 32%, 27% from GVHD. The cumulative incidence of acute GVHD grade 2-4 and 3-4 was 63 and 41%, respectively. With a median follow-up of 18 months, the disease-free survival (DFS) and overall survival (OS) are 55 and 59%, respectively. For patients with AML and MDS (n=14), the DFS and OS is 71%. For patients undergoing a second transplant (n=14), the DFS and OS is 57%. In conclusion, this regimen is associated with acceptable toxicity but high rates of GVHD in high-risk patients undergoing URD HSCT. Encouraging disease control for patients with advanced myeloid malignancies was observed.

Donor leukocyte infusions in relapsed Hodgkin's lymphoma following allogeneic stem cell transplantation: CD3+ cell dose, GVHD and disease response

Nine patients with advanced Hodgkin's lymphoma (HL) who had undergone allogeneic stem cell transplantation (allo-SCT) received donor leukocyte infusions (DLIs) for treatment of persistent or progressive disease (PD). A total of 15 DLIs were performed, with four patients receiving more than one DLI. In four patients, prior salvage chemotherapy was administered. The median CD3+ cell dose administered was 77.5 x 10(6)/kg (range 5-285). GVHD developed in all but one patient. The response rate was 4/9 (44%). Three of these four responders developed GVHD and 3/4 had received chemotherapy. No correlation was observed between CD3+ cell dose infused and disease response. At the latest follow-up, three patients are alive and six have expired (PD n=3, nonrelapse mortality n=3). The median response duration was 7 months (range 4-9), with one response currently ongoing. These data suggest that DLIs for immunotherapy of recurrent HL have significant activity, although they frequently leads to GVHD. The small sample size does not allow any conclusion as to whether chemotherapy administration increases the chance of response. The CD3 cell dose infused does not seem to correlate with disease response.

An update on the management of relapsed and primary refractory Hodgkin’s disease

With the use of combined modality therapy for early stage disease and a risk-adapted approach for advanced stage disease, nearly 90% of patients with Hodgkin's lymphoma are cured with initial therapy. However, in patients who have primary refractory or relapsed disease, high-dose therapy and autologous stem cell transplantation is the best curative option. The use of peripheral blood progenitor cells has decreased transplant related mortality to less than 3%; but long-term progression-free survival as increased minimally. Although prognostic factors have been used to tailor therapy in de novo Hodgkin's lymphoma their utility in the relapsed-refractory setting has not been exploited. This update will discuss these important prognostic factors and try to guide oncologists in treatment decisions in this setting.

Epstein-Barr virus-associated Hodgkin's lymphoma

Survivors of Hodgkin's lymphoma (HL) frequently have many years to experience the long-term toxicities of combined modality therapies. Also, a significant proportion of HL patients will relapse or have refractory disease, and less than half of these patients will respond to current salvage strategies. 30-50% of HL cases are Epstein-Barr virus associated (EBV-positive HL). The virus is localized to the malignant cells and is clonal. EBV-positive HL is more frequent in childhood, in older adults (>45 years) and in mixed cellularity cases. The survival of EBV-positive HL in the elderly and the immunosuppressed is particularly poor. Despite improvements in our understanding of EBV-positive HL, the true contribution of EBV to the pathogenesis of HL remains unknown. Increased knowledge of the virus' role in the basic biology of HL may generate novel therapeutic strategies for EBV-positive HL and the presence of EBV-latent antigens in the malignant HL cells may represent a target for cellular immunotherapy.

Allogeneic transplantation of hematopoietic stem cells after nonmyeloablative conditioning for Hodgkin’s disease: indications and results

A number of treatment options are available for patients with relapsed Hodgkin's disease (HD). Radiotherapy, salvage chemotherapy, high-dose therapy (HDT) followed by autologous transplantation, and classical or nonmyeloablative conditioning followed by allogeneic transplantation can all be effective in patients with relapsed HD. Patients with early relapse after modern first-line chemotherapy, as well as patients with primary progressive disease, will be candidates for innovative approaches including nonmyelablative stem cell transplant (NST). Although initial results with NST look promising, more time and structured study of both HD and NST will be necessary to ultimately define the role of NST in this disease.

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.

Hematopoietic chimerism and central tolerance created by peripheral-tolerance induction without myeloablative conditioning

Allogeneic hematopoietic chimerism leading to central tolerance has significant therapeutic potential. Realization of that potential has been impeded by the need for myeloablative conditioning of the host and development of graft-versus-host disease (GVHD). To surmount these impediments, we have adapted a costimulation blockade-based protocol developed for solid organ transplantation for use in stem cell transplantation. The protocol combines donor-specific transfusion (DST) with anti-CD154 mAb. When applied to stem cell transplantation, administration of DST, anti-CD154 mAb, and allogeneic bone marrow leads to hematopoietic chimerism and central tolerance with no myeloablation and no GVHD. Tolerance in this system results from deletion of both peripheral host alloreactive CD8+ T cells and nascent intrathymic alloreactive CD8+ T cells. In the absence of large numbers of host alloreactive CD8+ T cells, the transfusion that precedes transplantation need not be of donor origin, suggesting that both allospecific and non-allospecific mechanisms regulate engraftment. Agents that interfere with peripheral transplantation tolerance impair establishment of chimerism. We conclude that robust allogeneic hematopoietic chimerism and central tolerance can be established in the absence of host myeloablative conditioning using a peripheral transplantation tolerance protocol.

Induction of tolerance for islet transplantation for type 1 diabetes

Type 1 diabetes is an autoimmune disorder characterized by selective destruction of pancreatic b cells and absolute insulin deficiency. Even when treated well, control is imperfect and complications inevitable. Advances in immunosuppressive drugs and preparation of donor islets have recently made curative islet transplantation a reality for type 1 diabetes. Unfortunately, short-term side effects and long-term health risks of lifelong systemic immunosuppression compromise the otherwise extraordinary benefits that accrue from a successful graft. Our current goal is to obviate the need for immunosuppression and achieve islet graft tolerance. New protocols based on costimulation blockade have brought us close to that goal, inducing states of both peripheral and central transplantation tolerance. These have overcome both allograft rejection and recurrent autoimmunity, but potentially detrimental effects of environmental agents on tolerance are not yet fully understood. Studies of the underlying mechanisms have provided new insights into the nature of both tolerance and autoimmunity.

Hematopoietic stem cell transplantation for autoimmune diseases in developing countries: current status and future prospectives

In this paper we present preliminary results of hematopoietic stem cell transplantation for autoimmune diseases in Brazil and China. Chinese experience transplanting lupus is significant and the Brazilian experience with several autoimmune diseases is growing. We discuss peculiar conditions in developing countries which could affect the results, and future prospectives for the organization of phase III randomized trials in those countries.

Blockade of the CD40/CD154 pathway enhances T-cell-depleted allogeneic bone marrow engraftment under nonmyeloablative and irradiation-free conditioning therapy

BACKGROUND

T-cell-depleted bone marrow transplantation (TDBMT) can prevent graft-versus-host disease (GvHD). However, depleting T cells from allogeneic bone marrow often results in failure of bone marrow engraftment under irradiation conditioning. It is not know whether donor T cells are essential for bone marrow engraftment and whether blocking the CD40/CD154 pathway promotes allogeneic TDBM engraftment under nonmyeloablative and irradiation-free fludarabine phosphate and cyclophosphamide conditioning therapy.

METHODS

Using fully major histocompatibility complex (MHC)-matched mouse models, we investigated whether donor T cells are essential for bone marrow engraftment under fludarabine phosphate and cyclophosphamide conditioning therapy. We also determined whether the barrier of allogeneic TDBM could be overcome by blocking the CD40/CD154 pathway. Donor chimerism was detected by flow cytometric analysis. Donor-specific tolerance through establishing mixed chimerism was tested in vivo by skin transplantation and in vitro by mixed leukocyte reaction and enzyme-linked immunospot (ELISPOT) assay.

RESULTS

Compared with unmodified bone marrow, TDBM resulted in poor engraftment when fully MHC-mismatched donors were used. However, anti-CD154 monoclonal antibody (mAb) treatment significantly enhanced donor TDBM engraftment. TDBM engraftment was also seen in CD154 knockout mice. A stable and high level of multilinage donor chimerism was achieved. Recovery of host CD3 T cells was suppressed, and recovery of donor CD3 T cells was promoted, after TDBMT and anti-CD154 mAb treatment. Donor chimerism was established by TDBMT induced donor-specific tolerance in vivo and in vitro.

CONCLUSION

Donor T cells facilitate bone marrow engraftment under nonmyeloablative and irradiation-free conditioning therapy, and the blocking the CD40/CD154 pathway can replace donor T cells to promote TDBM engraftment.

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.

Successful Allogeneic Stem Cell Transplantation with Nonmyeloablative Conditioning in Patients with Relapsed Hodgkin's Disease Following Autologous Stem Cell Transplantation

Use of myeloablative preparative therapy and allogeneic stem cell transplantation (alloSCT) as salvage therapy for adult patients with relapsed hematologic malignancies after autologous stem cell transplantation (autoSCT) is generally unsuccessful due to very high treatment-related mortality rates. We report here the outcome of HLA-matched related donor alloSCT following nonmyeloablative preparative therapy in two patients with Hodgkin's disease, relapsed after autologous stem cell graft. Times from autoSCT to alloSCT were 9 and 11 months, respectively. Preparative therapy consisted of the following: oral busulfan, 4 mg/kg on days -6 and -5; intravenous (i.v.) cyclophosphamide, 350 mg/m2 on days -4, -3 and, -2, and i.v. fludarabine, 30 mg/m2 on days -4, -3, and -2; oral cyclosporin A (CyA) 5 mg/kg was begun on day -1 and i.v. methotrexate 5 mg/m2 was delivered on days +1, +3, +5, and +11. Both patients achieved initial mixed chimerism as defined as > 1% donor peripheral white blood cells and did not receive prophylactic donor lymphocyte infusions; both showed conversion to final full-donor chimerism. Stage I acute graft-vs.-host disease occurred in one patient and both achieved sustained complete response. One patient died on day 233 as a consequence of drug-induced pulmonary toxicity, whereas the other patient remains in continued complete remission 513 days after allograft. This nonmyeloablative alloSCT strategy was well tolerated, was completed entirely on an out-patient basis, and can result in durable disease-free survival among patients with Hodgkin's disease after failed autoSCT. Further follow-up and evaluation of additional patients are required to conclusively establish the role of this strategy in treatment of hematologic malignancies after autologous transplantation.

'GVHD': graft-versus-host disease or graft-versus-Hodgkin's disease? An old acronym with new meaning

The majority of patients with relapsed or refractory Hodgkin's lymphoma (HL) will not be cured with standard therapy. Relapse rates remain high even after autologous stem cell transplantation (SCT), particularly for patients with high-risk disease. Allogeneic SCT offers several potential advantages for patients with HL. It is feasible when autologous stem cells are not available and stem cell grafts will be tumor free. Perhaps a more important advantage is the potential to generate a graft-versus-Hodgkin's lymphoma (GVHL) effect. Unfortunately, although allogeneic SCT may cure some HL patients, treatment-related mortality has been unusually high, and superior survival, when compared to autologous SCT, has not been demonstrated. Nonmyeloablative conditioning and allogeneic SCT may induce a direct GVHL reaction with less conditioning regimen-related toxicity and ultimately may have the potential to improve cure rates and survival for advanced HL patients.

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.

Role of allogeneic stem cell transplantation in relapsed or refractory Hodgkin's disease

Little information is available regarding allogeneic stem cell transplantation (alloSCT) and Hodgkin's disease (HD). Autologous stem cell transplantation (autoSCT) is usually preferred to alloSCT due to its widespread availability, lack of the immunological problems intrinsic to the development of graft-versus-host disease (GvHD), and the infrequent bone marrow involvement present in HD patients undergoing high-dose chemotherapy/radiotherapy. AlloSCT has been associated with a high transplant-related mortality (TRM) in patients with HD due to a high incidence of GvHD and of fatal infectious events after transplantation. The poor outcome of these patients after alloSCT may reflect in part the advanced status of the disease at transplantation and the poor performance status of the patient population allografted. Furthermore, the high TRM present in t h e conventional alloSCT setting hasnever allowed a proper evaluation of a possible graft-versus-Hodgkin's effect. In an effort to reduce the TRM associated with alloSCT, low-intensity regimens have been developed; the curative potential of these protocols would rely on the graft-versus-leukemia effect of the allogeneic infusion more than in the conditioning regimen per se. Although the number of HD patients allografted with reduced-intensity protocols is low and the follow-up still short, TRM seems lower than in the conventional allograft setting despite a similar incidence of acute GvHD (aGvHD). Overall and progression-free survival seem promising, and patients developing aGvHD after transplantation or donor lymphocyte infusions seem to be at a lower risk of relapse than those not presenting this complication.

Chemoresistant or aggressive lymphoma predicts for a poor outcome following reduced-intensity allogeneic progenitor cell transplantation: an analysis from the Lymphoma Working Party of the European Group for Blood and Bone Marrow Transplantation

We report the outcome of reduced-intensity allogeneic progenitor cell transplantation (alloPCT) for 188 patients with lymphoma from the Working Party Lymphoma of the European Group for Blood and Bone Marrow Transplantation (EBMT). The median age of the patients was 40 years, the median number of prior treatment courses was 3, and 48% of patients had undergone a prior autologous transplantation. Eighty-four percent of the patients received conditioning with fludarabine-based regimens and 10% with the BEAM (BCNU, etoposide, cytosine arabinoside, melphalan) protocol. Full donor chimerism was confirmed in 71% of 100 patients assessed. Acute graft-versus-host disease (GVHD) developed in 37% of patients and chronic GVHD in 17%. A disease response to donor leukocyte infusion (DLI) was seen in 10 of 14 patients. With a median follow-up of 283 days, the overall survival rates at 1 and 2 years were 62% and 50%, respectively. The 100-day and 1-year transplantation-related mortality (TRM) rates were 12.8% and 25.5%, respectively, and were significantly worse for older patients. The probability of disease progression at 1 year for patients with chemoresistant and chemosensitive disease were 75% and 25%, respectively (P =.001). The progression-free survival at 1 year was 46% and was significantly better for those with chemosensitive disease, Hodgkin disease (HD), and low-grade non-Hodgkin lymphoma (NHL). Patients with high-grade NHL, mantle cell lymphoma, or chemoresistant disease had a poor outcome. Reduced-intensity progenitor cell transplantation is associated with a reduced TRM and may control advanced HD and low-grade NHL. A longer period of follow-up is required to determine the benefit of DLI and the graft-versus-lymphoma effect.

Reduced intensity preparative regimens for allogeneic hematopoietic stem cell transplantation: a single center experience

According to recent reports, fast engraftment with minimal transplant-related toxicity and mortality (TRT, TRM) can be achieved by using reduced-intensity preparative regimens in allogeneic hematopoietic stem cell transplantation (HSCT). We report our experience with related (39%) and unrelated (61%) HSCT in 44 high risk patients (AML, ALL, CML, CLL) receiving either busulfan/fludarabine or busulfane/fludarabine/ATG or TBI/fludarabine as reduced-intensity preparative regimens. Organ toxicity was minimal with mild mucositis and no major bleeding. Acute GVHD was recorded in 64% of the patients. Twenty-three patients achieved complete remission after transplantation, and complete chimerism was obtained in all patients with stable engraftment (35 patients). Twenty-nine patients died: 15 due to relapse/progression, 14 due to TRM. Survival with median follow-up of 18.5 months was significantly better in patients with matched related transplants compared to patients with other transplants. However, there was no difference between related and unrelated transplants with regard to engraftment, TRM and GVHD. In conclusion, our results in high-risk patients transplanted in CR or with smoldering leukemia from a related donor are encouraging, although a longer follow-up and a larger group of patients is needed in order to evaluate the role of different reduced-intensity preparative regimens in unrelated and related HSCT.

Gene therapy-based treatment for HIV-positive patients with malignancies

Gene therapy for the treatment of HIV has long been a goal of many investigators. The majority of trials have involved the use of lymphocytes transduced with vectors promoting resistance to HIV infection or replication. Unfortunately, the results have been less than encouraging with low-level marking and, more importantly, clearance of these lymphocytes from the circulation. Conversely, gene-modified hematopoietic stem cells appear able to introduce foreign transgenes while avoiding immunologic clearance. Furthermore, the use of less toxic conditioning regimens for allogeneic transplantation provides an attractive approach to conferring HIV resistance while allowing treatment of HIV-related disorders such as malignancies. This combination of nonmyeloablative allogeneic transplantation using gene-modified hematopoietic stem cell theoretically overcomes the high transplant mortality associated with traditional conditioning regimens in patients with HIV as well as providing a self-renewing source of HIV-resistant cells. To assess the safety and feasibility of such an approach, a clinical protocol was initiated in those patients infected with HIV with a hematologic malignancy meeting the standard indications for allogeneic transplantation and provided here is an update to the previously published original report. Only patient 1 received genetically modified cells. Both patients tolerated the procedure with no effect on viral load and improved CD4 counts, and patient 1 remains in complete remission from acute myelogenous leukemia 3 years post transplant. Patient 2 also achieved clinical remission from chemorefractory Hodgkin's disease but died of relapsed disease 12 months after transplantation. Vector-transduced cells remain detectable at low levels more than 3 years post-transplantation, suggesting the potential for gene therapy as a reasonable goal for the treatment of HIV.

Role of nonmyeloablative allogeneic stem-cell transplantation after failure of autologous transplantation in patients with lymphoproliferative malignancies

PURPOSE

Conventional allogeneic stem-cell transplantation (SCT) after a prior failed autograft is associated with a transplant-related mortality rate of 50% to 80%. The aim of the current study was to evaluate the safety and efficacy of sibling, HLA-matched, nonmyeloablative allogeneic SCT with donor lymphocyte infusion (DLI) in patients with lymphoid malignancy after failure of autologous SCT.

PATIENTS AND METHODS

A total of 38 patients with refractory, progressive, or relapsed disease after autologous SCT were entered onto this study. The conditioning regimen consisted of the humanized monoclonal antibody CAMPATH-1H, fludarabine, and melphalan. Fifteen of 35 assessable patients received DLI after SCT.

RESULTS

Sustained neutrophil engraftment was achieved in 37 recipients, and platelet engraftment was achieved in 35 patients. The estimated transplant-related mortality was 7.9% at day 100 and 20% at 14 months, the median duration of follow-up. Eight patients experienced grade I/II acute graft-versus-host disease (GVHD) after transplantation, but no grade III/IV GVHD was observed in this setting. However, grade III/IV GVHD occurred in seven patients who received DLI. The actuarial overall survival at 14 months was 53%, with a progression-free survival of 50%. DLI produced a further response in three of 15 recipients.

CONCLUSION

Nonmyeloablative allogeneic SCT after CAMPATH-1H-containing conditioning is a relatively safe option compared with conventional allogeneic transplantation for patients who have failed previous autologous SCT. The low incidence of early GVHD enabled the subsequent administration of DLI to improve further clinical responses in this poor-risk group of lymphoma and myeloma patients.

Reduced-intensity allogeneic transplantation for lymphoma

Reduced-intensity allogeneic transplants are promising, increasingly used treatments for hematologic malignancies, exploiting graft-versus-tumor effects for eradicating malignancies. This article reviews approximately 40 published reports of reduced-intensity allogeneic transplants in lymphomas. Overall, reduced-intensity allogeneic transplants have been well tolerated and have produced encouraging results despite a diversity of transplant approaches used largely in heavily pretreated and older patients. Of 368 lymphoma patients who underwent reduced-intensity allogeneic transplants, 66.3% had responses, most of which were complete. Many had chemotherapy-refractory lymphomas, including some that relapsed after autologous transplants. Although the short follow-up periods of many studies do not permit assessments of response duration, protracted remissions were reported in some studies. Additionally, some patients entered molecular remissions, suggesting that graft-versus-tumor effects could, by themselves, cure some lymphomas. Graft-versus-host disease is the major risk of reduced-intensity allogeneic transplants, and treatment methods need refinement to reduce transplant risks while preserving graft-versus-tumor effects. Controlled trials involving patients with earlier-stage disease appear warranted to define better the role of reduced-intensity allogeneic transplants in treating lymphomas.

Non-myeloablative hematopoietic stem cell transplantation (NST) in the treatment of human malignancies: from animal models to clinical practice

NST is becoming a widely accepted method for allogeneic HSCT. Much experience has been gained, and the biology, indications and limitations are becoming clearer. Nonmyeloablative conditioning allows consistent engraftment of allografts from matched related, unrelated, and even partially matched donors. NST has been able to reduce the toxicity of allogeneic HSCT. The better immediate outcome produces better overall DFS. NST was feasible in elderly patients with almost no upper age limit, and in patients with organ dysfunction or other comorbidities precluding standard ablative conditioning. NST has also reduced the regimen-related toxicity of allogeneic HSCT in high-risk setting such as HSCT in heavily pretreated patients or following failure of a prior transplant procedure and in the unrelated setting. NST is rapidly becoming the treatment of choice in these indications where toxicity of standard ablative therapy is unacceptable. In certain malignancies such as in NHL, Hodgkin's disease and multiple myeloma, standard ablative NST has been reported to result in exceptionally high treatment related mortality, and NST is being investigated as a more reasonable alternative. NST may reduce the toxicity of the procedure even in younger patients who are eligible for ablative HSCT as well, however the long-term impact on patient outcome in this group is not yet established, and NST merits further investigation in prospective comparative trials. As described above, the known susceptibility of the underlying malignancy to GVT, the response to prior chemotherapy and bulk of residual disease, and the type of donor are other factors to consider when considering NST, and when selecting a regimen. The optimal preparative regimen needs to be defined. Ultimately less chemotherapy will be used and more specific immune-modulation, rather than intense nonspecific immunosuppression, will be used to achieve HVG tolerance. Preliminary animal models using costimulation blockade for specific induction of tolerance are promising steps towards achievement of this goal. Although much progress has been achieved with consistent achievement of engraftment with NST, GVHD and disease recurrence remain major obstacles to successful treatment. Existing clinical data suggest that NST does limit the incidence and severity of GVHD. Limitation of regimen-related toxicity, and bilateral transplantation tolerance afforded by mixed chimerism, are believed to have a major role in limiting GVHD. However GVHD remains the primary cause of treatment-related mortality. The development of techniques to separate GVHD and GVL are essential for further improvement of NST outcome. Better understanding of the biology and targets of GVHD and GVL may allow the elimination of alloreactive T-cells responsible for GVHD from the graft while retaining T-cells with GVL and infection control potential. Recurrence of the underlying malignancy is a major complication when NST is attempted in patients with chemo-refractory diseases and with high tumor bulk. Reduced toxicity regimens such as the FB/ATG regimen have been somewhat more successful in controlling disease progression until a potent GVT effect is established. However novel approaches are urgently required. NST serves as a platform for cellular immunotherapy. Judicious use of pre-emptive DLI needs to be explored. DLI may be amplified by activation of donor lymphocytes with IL-2 or in vivo administration of IL-2. Identification of tumor antigens will lead the way to ex-vivo generation and expansion of tumor specific cytotoxic T-lymphocytes to be used as potent immunotherapy without the hazards of GVHD. Allogeneic transplantation is rapidly changing from administration of supralethal doses of chemotherapy and radiation, trying to physically eliminate the 'last tumor cell', to the more subtle and tolerated sophisticated immunotherapy. This effort will focus on specific induction of HVG tolerance followed by induction of tumor-specific GVT effect to cure the underlying malignancy.

Reduced intensity conditioning regimen followed by glycosylated G-CSF mobilized PBSCT in patients with solid tumors and malignant lymphomas

The aim of this pilot study was to exploit the graft-versus-tumor potential of allogeneic transplants while improving safety of the procedure. Twelve patients with advanced hematological malignancies and solid tumors underwent a low intensity conditioning regimen (fludarabine and cyclophosphamide) followed by an allogeneic peripheral blood stem cell transplantation. The median time to achieve an absolute neutrophil count of more than 0.5 x 10(9)/l and an untransfused platelet count of more than 20 x 10(9)/l was 15 and 14 days, respectively. The main extra-hematological toxicities were mucositis and infections. Acute graft-versus-host (GVHD) disease was experienced by 62% of evaluable patients (grade II/B or III/C 80%) responsive to steroids. Extensive chronic GVHD was observed in 62% of patients. Non-relapse transplant-related mortality by day +30 was observed in three patients (25%). Eight out of 12 patients were full donor chimeric by day +100. One patient showed a mixed chimerism at day +37 when he died from progressive disease. One patient was in complete remission (CR) before allogeneic transplantation, and after transplantation four patients achieved CR and four experienced progressive disease. Our study confirms that a low intensity conditioning regimen for allogeneic stem cell transplantation is feasible and effective in heavily pretreated patients.

Viral abrogation of stem cell transplantation tolerance causes graft rejection and host death by different mechanisms

Tolerance-based stem cell transplantation using sublethal conditioning is being considered for the treatment of human disease, but safety and efficacy remain to be established. We have shown that mouse bone marrow recipients treated with sublethal irradiation plus transient blockade of the CD40-CD154 costimulatory pathway develop permanent hematopoietic chimerism across allogeneic barriers. We now report that infection with lymphocytic choriomeningitis virus at the time of transplantation prevented engraftment of allogeneic, but not syngeneic, bone marrow in similarly treated mice. Infected allograft recipients also failed to clear the virus and died. Postmortem study revealed hypoplastic bone marrow and spleens. The cause of death was virus-induced IFN-alphabeta. The rejection of allogeneic bone marrow was mediated by a radioresistant CD8(+)TCR-alphabeta(+)NK1.1(-) T cell population. We conclude that a noncytopathic viral infection at the time of transplantation can prevent engraftment of allogeneic bone marrow and result in the death of sublethally irradiated mice treated with costimulation blockade. Clinical application of stem cell transplantation protocols based on costimulation blockade and tolerance induction may require patient isolation to facilitate the procedure and to protect recipients.

Hodgkin's disease

Significant progress has been made over the past decade in the classification, diagnosis, staging, prognosis, and treatment of Hodgkin's disease (HD). A new classification system has recognized differences in the natural history of certain subtypes. The introduction of positron emission tomography has improved the accuracy of non-invasive staging. New prognostic indices have led to the development of risk-adapted treatment strategies. The serious long-term side effects of extended-field radiotherapy have prompted the increasing use of chemotherapy in conjunction with limited radiotherapy for early-stage patients. Combination chemotherapy remains the treatment of choice for advanced HD, and new dose-intense regimens appear to have improved activity. Patients who relapse now have a more favorable prognosis with the availability of active salvage regimens, autologous stem cell transplantation, and novel biologic agents.

Second autologous stem cell transplant for multiply relapsed Hodgkin's disease

Therapeutic options for patients with Hodgkin's disease who relapse after high-dose chemotherapy with autologous stem cell support are limited. Salvage chemotherapy is not curative, and allogeneic stem cell transplantation in this setting is associated with mortality rates of 40-65%. We report our institution's experience with second autologous transplants in this patient population. Five patients (median age 36) with relapsed Hodgkin's disease underwent a second autologous stem cell transplant at a median of 66 months after first transplant. Four patients received CBV, and one patient received BuCy as conditioning. Neutrophil and platelet engraftment occurred by days +10 and +16, respectively. All patients achieved a complete response, and no relapses have occurred after a median follow-up of 42 months. All four patients who received CBV developed interstitial pneumonitis, and two patients died of pulmonary complications 37 and 48 months following second transplant. Three patients remain alive and disease-free 41, 42 and 155 months after second transplant. These data indicate that second autologous transplantation should be considered for selected patients who relapse after a prolonged response to first autologous transplant. However, BCNU pneumonitis is the major toxicity in patients who have undergone previous mantle radiation and received busulfan with first transplant.

Hematopoietic stem cell transplantation in Hodgkin disease

Intensive therapy and autologous stem cell transplantation represent the standard of care in most patients whose Hodgkin disease has not been cured with conventional chemotherapy. With more prolonged follow-up of autografted patients, the problems with autologous stem cell transplantation are clear. In particular, recurrent disease and late transplant-related complications limit the effectiveness of this approach. A number of autologous stem cell transplantation studies have reported prognostic factors that will help identify patients at high risk for relapse. Several new approaches for decreasing recurrence rates are discussed, including novel immune strategies and re-evaluation of allogeneic stem cell transplantation. Although the risk of secondary malignancy and other causes of late morbidity and mortality after autologous stem cell transplantation is relatively low, current studies contribute to understanding of the pathogenesis of these complications and may diminish their impact in the future.

Nonmyeloablative conditioning followed by transplantation of genetically modified HLA-matched peripheral blood progenitor cells for hematologic malignancies in patients with acquired immunodeficiency syndrome

To assess the safety and efficacy of nonmyeloablative allogeneic transplantation in patients with HIV infection, a clinical protocol was initiated in patients with refractory hematologic malignancies and concomitant HIV infection. The results from the first 2 patients are reported. The indications for transplantation were treatment-related acute myelogenous leukemia and primary refractory Hodgkin disease in patients 1 and 2, respectively. Only patient 1 received genetically modified cells. Both patients tolerated the procedure well with minimal toxicity, and complete remissions were achieved in both patients, but patient 2 died of relapsed Hodgkin disease 12 months after transplantation. Patient 1 continues in complete remission with undetectable HIV levels and rising CD4 counts, and with both the therapeutic and control gene transfer vectors remaining detectable at low levels more than 2 years after transplantation. These results suggest that nonmyeloablative allogeneic transplantation in the context of highly active antiretroviral therapy is feasible in patients with treatment-sensitive HIV infection.