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

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.

Allogeneic haemopoietic stem cell transplantation for non-Hodgkin's lymphoma

This chapter outlines the rationale for allogeneic haemopoietic stem cell transplantation in non-Hodgkin's lymphoma and pertinent results from published studies. Trials comparing allogeneic with autologous transplantation are discussed, as are disease-specific results for low-grade (including transformed), mantle cell and high-grade (Burkitt's and lymphoblastic) subtypes of the disease. Allogeneic transplantation for non-Hodgkin's lymphoma in the paediatric population, the use of unrelated donors, allografting after failed autologous or allogeneic transplantation, the graft-versus-lymphoma effect, the use of donor leukocyte infusions and non-myeloablative allografts are considered.

Infectious risks and outcomes after stem cell transplantation: are nonmyeloablative transplants changing the picture?

PURPOSE OF REVIEW

Opportunistic infections contribute to morbidity and mortality after myeloablative allogeneic stem cell transplantation. The development of nonmyeloablative or toxicity-reduced conditioning regimens for allogeneic hematopoietic stem cell transplantation might change this picture significantly. These regimens are in general highly immunosuppressive, but effects on myelopoiesis and mucosal toxicities are usually reduced compared with myeloablative hematopoietic stem cell transplantation conditioning regimens. This review summarizes the infectious risks associated with each type of hematopoietic stem cell transplantation conditioning regimen, and presents the results of early clinical studies.

RECENT FINDINGS

Although the data are preliminary, the results of recent studies suggest that nonmyeloablative conditioning regimens may decrease the risks of bacterial infections associated with mucosal damage and persistent neutropenia; however, risks for late viral and fungal infections persist during severe graft versus host disease. Results of several case reports and series emphasize that therapeutic outcomes of infections may be improved in patients who receive nonmyeloablative conditioning regimens.

SUMMARY

Infectious risks and outcomes after hematopoietic stem cell transplantation appear to be in evolution given the introduction of alternative, nonmyeloablative conditioning regimens. Although infections remain a prominent cause of transplant-related mortality, the timing and types of infections may differ. Further studies are necessary to define appropriate preventative strategies, and to determine whether patients with ongoing infections might benefit from nonmyeloablative hematopoietic stem cell transplantation.

Allogeneic hemopoietic stem cell transplantation in patients with myelodysplastic syndrome or myelofibrosis

Myelodysplastic syndrome (MDS) and myeloproliferative disorders associated with myelofibrosis (MF) are stem cell disorders, and hemopoietic stem cell transplantation (HSCT) is currently the only therapy with curative potential. Among patients with less advanced MDS, 3 year survivals of 65% to 70% are achievable with HLA-identical related and HLA-matched unrelated donors. The probability of relapse is < 5%. Among patients with advanced disease (> or = 5% marrow blasts), about 35 to approximately 45% and 25 to approximately 30%, respectively, are surviving in remission after transplantation from related or unrelated donors. The incidence of post-transplant relapse is 1035%. Criteria of the International Prognostic Scoring System (IPSS), originally developed for nontransplanted patients, also predict survival following transplantation. Patients with MF, either idiopathic or on the basis of pre-existing disorders, are also transplanted successfully with stem cells from related or unrelated donors. Transplants early in the disease, before leukemic transformation, are successful in 60 to approximately 80% of patients. Success rates are lower in patients who have developed MDS or leukemia. New conditioning regimens have permitted successful HSCT even in patients in the seventh decade of life. Results with a regimen using a combination of busulfan (targeted to predetermined plasma levels) and cyclophosphamide are particularly encouraging. Improved survival with transplants from unrelated volunteer donors may, in part, reflect selection of donors on the basis of high resolution (allele-level) HLA typing. Nevertheless, transplant-related morbidity and mortality, including graft- vs. -host disease, remain challenges that need to be addressed with innovative approaches.

Eradication of virus-infected T-cells in a case of adult T-cell leukemia/lymphoma by nonmyeloablative peripheral blood stem cell transplantation with conditioning consisting of low-dose total body irradiation and pentostatin

We describe the case of a 55-year-old man with adult T-cell leukemia/lymphoma (ATL) in first remission who underwent nonmyeloablative allogeneic peripheral blood stem cell transplantation with conditioning consisting of 4 courses of pentostatin and low-dose total body irradiation. Complete chimerism in peripheral blood was achieved on day 42 without severe myelosuppression. Concomitantly, the proviral DNA load for human T-cell leukemia virus I (HTLV-I) in peripheral blood mononuclear cells decreased below detectable limits and was still undetectable on day 270. This fact indicates that eradication of ATL cells is feasible by induction of an alloimmune response without high-dose chemoradiotherapy.

Allogeneic hematopoietic stem cell transplantation for progressive follicular lymphoma

Between 1993 and 2000, 24 patients with follicular lymphoma underwent high-dose chemo/radiotherapy and allogeneic hematopoietic stem cell transplantation (HSCT). Median age was 44 years, median interval from diagnosis to HSCT was 24 months and the median number of prior lines of treatment was three. Donor source was HLA matched sibling (23) or matched unrelated donor (one). Conditioning therapy was busulfan based in 22 patients and included total body irradiation in two. All patients received i.v. cyclosporine A and short-course methotrexate for GVHD prophylaxis. Nineteen patients are alive, a median of 2.3 years post HSCT. Death occurred due to transplant complications in four patients and one patient died of a stroke 10 months post HSCT. No patients have relapsed. The overall and progression-free survival was 78% (95% CI 63-97). Allogeneic HSCT for patients with progressive follicular lymphoma is feasible and may result in prolonged disease-free survival.