Allogeneic hematopoietic cell transplantation after fludarabine and 2 Gy total body irradiation for relapsed and refractory mantle cell lymphoma

We carried out HLA-matched related (n = 16) and unrelated (n = 17) hematopoietic cell transplantation (HCT) in 33 patients with relapsed and refractory mantle cell lymphoma after nonmyeloablative conditioning with fludarabine and 2 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclosporine and mycophenolate mofetil. Fourteen patients had failed high-dose autologous HCT. Of the 33 patients studied, 31 had stable engraftment, whereas 2 patients experienced nonfatal graft rejections. The incidences of acute grades II, III, and IV, and chronic graft-versus-host disease (GVHD) were 27%, 17%, 13%, and 64%, respectively. The overall response rate in the 20 patients with measurable disease at the time of HCT was 85% (n = 17; 75% complete remissions [CR] and 10% partial remissions [PR]), whereas 3 patients had progressive disease. Only one of the 17 patients who responded and none of the 13 who received transplants in CR had disease relapse with a median follow-up of 24.6 months. Relapse and nonrelapse mortalities were 9% and 24%, respectively, at 2 years. The Kaplan-Meier probabilities of overall and disease-free survivals at 2 years were 65% and 60%, respectively. Allogeneic HCT after nonmyeloablative conditioning is a promising salvage strategy for patients with relapsed and refractory mantle cell lymphoma. The high response and low relapse rates with this approach suggest that mantle cell lymphoma is susceptible to graft-versus-tumor responses.

Cytopenia and hematopoietic recovery after low intensity conditioning transplants

AIM

To compare hematopoietic reconstitution after low intensity conditioning transplants and standard allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

We retrospectively analyzed the kinetics of cytopenia of 50 consecutive patients treated with HSCT during a 60 day posttransplant period. Twenty four patients were treated with a low intensity regimen (Fludarabine, 2 Gy total body irradiation) and 26 patients with the standard conditioning regimen. Patients who received the low intensity HSCT were analyzed in two groups, patients with engraftment of donor hematopoiesis and those who rejected the graft.

RESULTS

Patients treated with low intensity conditioning, regardless of its outcome, experienced significantly less severe cytopenia than the patients from the control group. Except for reticulocytes, the development of cytopenia was significantly slower in these patients, and the duration of severe cytopenia was significantly shorter. However, full neutrophil recovery (absolute neutrophil count >1.0 x 10(9)/L) took longer in patients with low intensity HSCT.

CONCLUSIONS

The kinetics of cytopenia and hematopoietic recovery after low intensity conditioning HSCT significantly differ from standard HSCT. There is no difference in the initial hematopoietic recovery between patients with or without engraftment after low intensity conditioning. This indicates that the onset, severity, and duration of the cytopenia are influenced primarily by the intensity of the conditioning and by the immunosuppressive regimen after transplantation. Effects are more pronounced for neutrophils than for platelets and reticulocytes.

A novel approach for prevention of lethal GVHD by selective elimination of alloreactive donor lymphocytes prior to stem cell transplantation

OBJECTIVE

Experiments were designed to investigate a new concept aiming for induction of graft-vs-malignancy (GVM) effect prior to stem cell transplantation (SCT). Mismatched lymphocytes given pre-SCT will be followed by a selective elimination of alloreactive donor lymphocytes, thus avoiding lethal graft-vs-host disease (GVHD).

METHODS

Recipient mice treated with sublethal total-body irradiation (TBI) received a single injection of allogeneic splenocytes, either naïve or rIL-2 activated (ADL), for induction of GVHD. To prevent lethal GVHD, cyclophosphamide (Cy) (200 mg/kg) or TBI (9 Gy) were given 4 days after cell inoculation. One day later, treated mice were rescued with syngeneic bone marrow cells.

RESULTS

Both Cy and TBI significantly (p < 0.001) prevented GVHD in all recipients inoculated with either naïve cells or ADL and all recipients survived more than 250 days. Control mice not rescued with CY or TBI died of GVHD within 20 to 25 days. A significant proportion of recipients inoculated with 4T1 tumor cells, treated with ADL followed by TBI 9 Gy, survived more than 250 days disease-free in comparison with 22 days in untreated control mice (p <0.001).

CONCLUSIONS

Attempting to induce short, yet effective, GVM effects before rather than after SCT, thus avoiding lethal GVHD, may represent an innovative approach for more effective yet safer use of SCT for tumor immunotherapy.

Allogeneic hematopoietic cell transplantation as treatment for hematological malignancies: a review

Allogeneic hematopoietic cell transplantation (HCT) was originally developed as a form of rescue from high-dose chemoradiotherapy, which is given both to eradicate malignancy and provide sufficient immunosuppression for allogeneic engraftment. The first attempts of allogeneic HCT in humans met with little success. However, a better understanding of the complexities of the human leukocyte antigen (HLA) system has allowed selecting compatible sibling donors, and the development of postgrafting immunosuppressive regimens has helped prevent serious graft-versus-host disease, thereby changing the role of allogeneic HCT from a desperate therapeutic maneuver to a curative treatment modality for many patients with malignant hematological diseases. In addition, the establishment of large registries of HLA-typed volunteers has permitted finding suitable unrelated donors for many patients without family donors. Further advances in the immunogenetics of HLA, especially typing by molecular techniques, have improved results after unrelated HCT, which have begun resembling those obtained with HLA-identical sibling grafts, at least in young patients. Important advances have also been made in the prevention and treatment of infectious complications and in other areas of supportive care. Since the late seventies, it has been recognized that allogeneic immunocompetent cells transplanted with the stem cells, or arising from them, mediated therapeutic anti-tumor effects independent of the action of the high-dose therapy, termed graft-versus-tumor (GVT) effects. This has prompted the recent development of non-myeloablative conditioning regimens for allogeneic HCT that have opened the way to include elderly patients and those with comorbid conditions. Remaining challenges include further advances in the prevention and treatment of both severe graft-versus-host disease and infections. Also, progress in adoptive transfer of T cells with relative tumor specificity and disease-targeted therapy with agents such as Imatinib, Rituximab or radiolabeled monoclonal antibodies would make allogeneic HCT even more effective.

Stem cell transplantation-harnessing of graft-versus-malignancy

PURPOSE OF REVIEW

Allogeneic transplantation can cure a number of hematologic malignancies; however, the cost in morbidity and mortality is high. Much of the toxicity is a direct consequence of the intensity of the conditioning regimen. It has gradually been recognized that the conditioning regimen is important but not critical for the success of transplantation, particularly in the less aggressive hematologic malignancies. The graft-versus-malignancy effect, that is, the recognition of residual cancer cells by the T cells of the donor, is a critical component of the transplantation process.

RECENT FINDINGS

This effect has been emphasized over high-dose therapy by using less intensive, and therefore less toxic conditioning regimens, thus allowing the graft-versus-malignancy effect to predominate. Reduced-intensity conditioning regimens have allowed the application of transplantation to older patients and to patients with underlying medical problems that preclude full-dose transplantation.

SUMMARY

Although the long-term results of this type of approach have not yet been defined, it appears to be effective in diseases such as chronic myelogenous leukemia, chronic lymphocytic leukemia, and low-grade lymphomas that are not intrinsically very aggressive. Although the therapy appears to be valuable, concerns about delayed immune reconstitution and graft-versus-host disease remain.

Diverse clinical applications using advantages of allogeneic peripheral blood stem cell transplantation

The diverse clinical applications of allogeneic peripheral blood stem cells based on use of their advantages are summarized. It is apparent that more stem cells and T-lymphocytes can be harvested by mobilization treatment with cytokines from healthy donors in allogeneic peripheral blood stem cell transplantation (PBSCT) than in bone marrow transplantation. It is also clear that a stronger graft-versus-tumor effect can be induced with allogeneic PBSCT than with bone marrow transplantation. One merit of allogeneic PBSCT is that it allows clinicians to design diverse clinical applications. It would appear that allogeneic PBSCT may be preferable in special clinical settings, such as advanced hematological malignancies, situations requiring a strong graft-versus-tumor effect, nonmyeloablative stem cell transplantation, and situations requiring a megadose of stem cells. Cytokine-primed peripheral blood stem cells can also be used for adoptive immunotherapy, such as a nonprimed donor lymphocyte infusion.

Indolent B-cell malignancies: immune recognition and antiself

B-cell malignancies appear to be ideal candidates for treatment with immunotherapeutic approaches. Monoclonal antibodies that target cell-surface determinants have been used as single agents in B-cell malignancies, in combination with chemotherapy, and coupled to other agents to create radioimmunoconjugates and immunotoxins. Another approach is to take advantage of the graft-vs.-lymphoma effect seen following allogeneic bone marrow transplantation. To exploit this effect without inducing the complication of graft-vs.-host disease, it is necessary to understand the mechanisms whereby lymphoma cells escape T-cell-mediated responses. CD40 activation may offer a means of increasing the immunogenicity of lymphoma cells and of stimulating allogeneic T-cell proliferation and cytokine production. Vaccination using tumor-specific antigens shows promise as a therapeutic strategy. Pre-clinical studies with immunoglobulin idiotype peptides have shown that humoral and cellular immune responses can be stimulated by antibodies to these peptides, but better tumor antigens need to be identified that can reliably generate cytotoxic T-cell responses. Candidate antigens include heteroclitic peptides from the immunoglobulin V region and newly identified antigens including the cytochrome P450 1B1. Clinical trials are ongoing in all these fields.

Allogeneic hematopoietic stem cell transplantation for metastatic breast cancer

The prognosis is poor and the options are limited for patients with metastatic breast cancer (MBC), especially for those patients who have previously received taxanes and anthracyclines; treatment strategies are primarily palliative. Murine models have demonstrated that allogeneic T cells are capable of eliciting graft-versus-tumor (GVT) effects against breast cancer, inhibiting growth of breast cancer cell lines in vivo, providing the rationale to pursue allogeneic adoptive cellular therapy as a strategy to treat MBC. However, the clinical application of allogeneic hematopoietic stem cell transplantation (alloHSCT) was limited by concerns over toxicity and unproven efficacy. The development of non-myeloablative (a.k.a. reduced-intensity) conditioning regimens, which have less treatment-related mortality but preserve the T-cell mediated GVT effects, led to increased investigation of alloHSCT in MBC. Early reports of non-myeloablative alloHSCT indicate that a clinical GVT effect against breast cancer does exist. The responses, observed in 20-40% of patients, appear to be associated with the development of complete donor lymphoid chimerism and may be delayed. In its current form, alloHSCT by itself is unlikely to result in complete eradication of MBC; however, it may serve as a therapeutic platform to complement and enhance the effects of existing cytotoxic therapies and immunotherapies (e.g. trastuzumab), as well as therapies under development (e.g. vaccines). Current data on alloHSCT for MBC should be interpreted cautiously and carefully used for the design of future studies to fully determine the clinical efficacy of this form of adoptive cellular therapy in MBC.

High-dose chemotherapy using BEAM for tumor debulking without stem cell support followed by early allogeneic reduced intensity conditioning transplantation to induce a graft-versus-lymphoma effect in patients with high risk or refractory lymphoma

In patients with refractory lymphoma, we tested the hypothesis that high-dose chemotherapy (BEAM) without stem cell support followed by a reduced intensity (RIC) allogeneic transplant with fludarabine and 2 Gy TBI 28 days later results in tumor debulking and establishment of a graft vs lymphoma effect, with acceptable toxicity. In a pilot protocol we treated 10 patients, 22-62 (median 47) years of age with high-risk or refractory Hodgkin's or non-Hodgkin's lymphoma. Donors were HLA identical siblings (eight) or unrelated volunteers. None died during the neutropenic phase after BEAM which lasted up to the RIC HSCT. The duration of neutropenia was 31-43 (median 36) days. All patients engrafted and nine achieved CR. All developed acute GvHD (median grade III) and all patients at risk developed chronic GvHD. Three patients died of GvHD. One relapsed and six patients are in continuous CR 10-32 (median 15) months after HSCT. This approach appears feasible and results in a high response rate. Neutropenia duration is of concern. It remains to be tested whether separation of debulking chemotherapy and induction of allogeneic effects confers an advantage.

Nonmyeloablative allogeneic stem cell transplantation for patients with unresectable pancreatic cancer

OBJECTIVES

To clarify whether nonmyeloablative allogeneic stem cell transplantation (NST) can produce the graft versus tumor (GVT) effect in patients with pancreatic cancer.

METHODS

A pilot trial of NST was conducted in 5 patients with unresectable pancreatic cancer. Preparative conditioning consisted of administration of 60 mg/kg cyclophosphamide on days 6 and 7 before transplantation, followed by 25 mg fludarabine per square meter of body surface on each of the last 5 days prior to transplantation. Cyclosporine was started 4 days before transplantation. Peripheral blood stem cells from the patients' HLA-identical siblings were transfused into the patients.

RESULTS

Complete donor T-cell chimerism in peripheral blood was obtained in 4 patients on day 15 after transplantation. NST resulted in tumor reduction in 2 patients as determined by CT, decreasing levels of tumor markers in 2 patients, pain relief in 2 patients, and a decrease in pleural fluid in 1 patient. Two patients developed acute graft versus host disease (GVHD) of grade II or III and 2 had chronic GVHD involving skin and/or liver. Administration of immunosuppressive drugs for the treatment of GVHD resulted in the elevation of tumor marker levels.

CONCLUSION

These findings are the first to suggest that NST induces a GVT effect on pancreatic cancer.

Allogeneic Hematopoietic Stem Cell Transplantation for Lymphoma

For patients with relapsed or refractory Hodgkin's or non-Hodgkin's lymphomas, allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option when autologous HSCT fails to achieve durable remission or is deemed inappropriate. Allogeneic HSCT can result in long-term survival even in patients with refractory lymphomas. The efficacy of allogeneic HSCT is attributed, at least in part, to an immune-mediated graft-versus-lymphoma (GVL) effect that can also be associated with significant toxicity resulting from graft-versus-host disease. However, clinical evidence of a potent GVL effect is inconsistent. Reduced-intensity conditioning before allogeneic HSCT can facilitate the use of this treatment in older patients and those at high risk. The decrease in toxicity with reduced-intensity regimens may be associated with a loss of antitumor effects. Patients with lymphoma should be selected for allogeneic HSCT on the basis of characteristics that strongly influence transplant outcomes, including histology, chemosensitivity, and donor source.

Reduced-intensity allogeneic stem cell transplantation for renal cell carcinoma: in vivo evidence of a graft-versus-tumor effect

We report the cases of 3 patients with advanced renal cell carcinoma who underwent reduced-intensity allogeneic stem cell transplantation. In 2 partial responders, histologic analyses of metastases revealed prominent accumulation of CD8+ T cells and degenerative changes of clear cell carcinoma, suggestive of induction of tumor-specific cytotoxic T lymphocytes.

Hematopoietic stem cell transplant as a platform for tumor immunotherapy

Blood or marrow transplantation (BMT) has been utilized as a cancer therapy with varying levels of success. While it has been an important option for many hematological malignancies, it has met with less success in solid tumors. More recently, new combinations of therapies with BMT have been developed to enhance the efficacy of this therapy and to expand the number of target tumors. This review highlights current uses of BMT, rationales for experimental approaches using BMT alone or as a part of a combination therapy, and reviews some of the novel therapies that have been developed in tumor immunotherapy with BMT, in addition to the implications for translation.

[Remission induction of refractory diffuse large B-cell lymphoma with allogeneic peripheral blood stem cell transplantation followed by interferon-alpha and donor lymphocyte infusion]

Graft-versus-lymphoma (GVL) effect has been described in patients with malignant lymphoma after allogeneic stem cell transplantation (alloSCT). The effect of interferon-alpha (IFN-alpha) on the GVL effect still remains unclear. Here we report on a 29-year-old woman with refractory diffuse large B-cell lymphoma (DLBL). Her clinical findings included multiple masses in the liver, stomach, bilateral kidneys, thyroid, vertebral bones and a bulky mediastinal mass. Since the patient did not respond to various combination chemotherapies and further developed superior vena cava syndrome, allogeneic peripheral blood stem cell transplantation (PBSCT) from a HLA-identical brother was carried out after a myeloablative TBI/CY-based conditioning regimen. DLIs have been also performed every 4 weeks since day +14. As a result, the lymphoma masses showed a partial response. In order to enhance the GVL effect, IFN-alpha was further given at a maximum of 3 MU four times per week. Although the patient only experienced graft-versus-host disease of the skin (grade II) even after both DLIs and IFN, complete clinical remission was observed. 200 days after transplantation, the patient is still disease-free and in good condition. This report suggests the curative potential of IFN-alpha combined with DLI after allogeneic SCT in refractory DLBL.

Matched unrelated donor bone marrow transplantation for the treatment of platinum refractory ovarian carcinoma: a case report

BACKGROUND

We are reporting on a case of platinum-refractory low-grade ovarian cancer responding to treatment with an allogeneic bone marrow transplantation from an unrelated donor.

CASE

The 37-year-old patient received a preparative regimen consisting of fludarabine 25 mg/m(2) on days -6, -5, -4, -3 and -2, melphalan 70 mg/m(2) on days -3 and -2, and thymoglobulin 2 mg/kg on days -3, -2 and -1. An unrelated HLA-compatible bone marrow was infused on day 0. Graft-versus-host disease prophylaxis consisted of tacrolimus and methotrexate. The patient demonstrated complete donor chimerism. Serial CT scans of the abdomen and pelvis over the following 15 months showed a slow regression of the malignant lesion.

CONCLUSION

Engraftment of an unrelated donor marrow was achieved in a patient with ovarian cancer and induced a tumor response. This suggests the presence of a graft-versus-tumor effect in ovarian cancer. Further study is underway.

The current status of hematopoietic stem cell transplantation for multiple myeloma

Multiple myeloma is often successfully controlled with conventional chemotherapy, but complete remissions are uncommon and cure is rare. High-dose therapy followed by autologous or allogeneic stem cells, employed for the treatment of multiple myeloma in the past 20 years, is promising as a means to increase remission rates and improve survival. Autologous transplants have not always demonstrated survival benefits in randomized studies because most of the patients transplanted relapse, while patients given conventional therapy can receive salvage transplants when they relapse. Efforts to improve the results of autologous transplant include targeted radiation, cytoprotective agents, tandem transplants, or post-transplant immunotherapy. Only allogeneic hematopoietic stem cell transplantation is potentially curative, due to a graft-versus-myeloma effect. While patients who receive either allogeneic or autologous stem cell transplants for multiple myeloma have similar 3-5 year survival, only allograft recipients appear to enjoy long-term disease-free survival. High transplant-related mortality associated with allogeneic stem cell transplantation is currently the major limitation to wider use of this potentially curative modality. Strategies designed to improve the therapeutic index of allografts include the use of nonablative conditioning regimens, peripheral blood cells rather than bone marrow, graft engineering, and targeted conditioning therapies such as bone-seeking radioisotopes.

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.

Outcome after autologous and allogeneic stem cell transplantation for patients with multiple myeloma: impact of graft-versus-myeloma effect

A total of 228 patients with multiple myeloma (MM), 166 patients receiving autologous transplantation (124 PBSC and 38 BM) and 66 patients receiving T-cell-depleted allogeneic transplantation were analyzed to compare overall survival (OS), progression-free survival (PFS) and risk of relapse. Patients receiving autologous transplantation had a significantly improved OS (P=0.006) and PFS (P=0.002) at 2 years with OS and PFS for autologous transplant 74% and 48%, respectively, compared with 51% and 28% for allogeneic transplantation. By 4 years after transplantation, outcome was similar with OS and PFS for autologous transplantation 41% and 23%, respectively, compared with 39% and 18% for allogeneic transplantation. The 4-year cumulative incidence of nonrelapse mortality was significantly higher in patients receiving allogeneic transplantation (24% vs 13%) (P=0.004). Relapse was the principle cause of treatment failure for both groups; however, there was a significantly reduced risk of relapse associated with allogeneic transplantation at 4 years: 46% for allograft vs 56% for autograft (P=0.02). Despite a lower risk of relapse after allogeneic transplantation, autologous transplantation is associated with improved OS and PFS compared with allogeneic transplantation in patients with MM. Strategies focused on reducing nonrelapse mortality in allogeneic transplantation may translate into an improved outcome for patients receiving allogeneic transplantation.

Possible allogeneic graft-versus-tumor effect in childhood melanoma

Patients with metastatic melanoma have a very poor prognosis despite contemporary biochemotherapy. A 14-year-old girl with stage IV melanoma and brain metastasis received a nonmyeloablative conditioning and a hematopoietic graft from an HLA-identical sibling. She had progression of disease in the first 2 months after transplantation. After withdrawal of immunosuppressant and establishment of a full donor chimeric status, peripheral disease response was documented by regression of metastatic disease and lack of tumor progression until 1 year after transplantation. She died of progressive disease 21 months after diagnosis and 17 months after transplantation. Her clinical course suggested the possible existence of an allogeneic graft-versus-melanoma response that prolonged her survival.

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.

CD3/CD28-costimulated T1 and T2 subsets: differential in vivo allosensitization generates distinct GVT and GVHD effects

Adoptive T-cell therapy using CD3/CD28 co-stimulation likely requires in vivo generation of antigen specificity. Because CD28 promotes TH1/TC1 (T1) or TH2/TC2 (T2) differentiation, costimulation may generate donor T1 or T2 cells capable of differentially mediating allogeneic graft-versus-tumor (GVT) effects and graft-versus-host disease (GVHD). Costimulation under T1 or T2 conditions indeed generated murine TH1/TC1 cells secreting interleukin-2/interferon-gamma (IL-2/IFN-gamma) or TH2/TC2 cells secreting IL-4/IL-5/IL-10. In vivo, allogeneic T1 cells expanded, maintained T1 secretion, and acquired allospecificity involving IFN-gamma and IL-5. In contrast, allogeneic T2 cells expanded less and maintained T2 secretion but did not develop significant allospecificity.Allogeneic, but not syngeneic, T1 cells mediated a GVT effect against host-type breast cancer cells, as median survival time (MST) increased from 25.6 +/- 2.6 (tumor controls) to 69.2 +/- 5.9 days (P < 1.2 x 10(-9)). This T1-associated GVT effect operated independently of fasL because T1 cells from gld mice mediated tumor-free survival. In contrast, allogeneic T2 cells mediated a modest, noncurative GVT effect (MST, 29 +/- 1.3 days; P <.0019). T1 recipients had moderate GVHD (histologic score, 4 of 12) that contributed to lethality after bone marrow transplantation; in contrast, T2 recipients had minimal GVHD (histologic score, 1 of 12). CD3/CD28 co-stimulation, therefore, generates T1 or T2 populations with differential in vivo capacity for expansion to alloantigen, resulting in differential GVT effects and GVHD.

Current concepts in allogeneic hematopoietic stem cell transplantation

Progress in allogeneic SCT will depend on several factors including the advances in the conventional treatment of diseases treated currently with allogeneic SCT, the expansion of the donor pool, the selective control of GVHD, the development of more effective and less toxic preparative regimens to eradicate the neoplastic cell population, the characterization of a new generation of hematopoietic growth factors and cytokines and the development of newer and safer techniques for ex-vivo manipulation of stem cells. The use of hematopoietic growth factor-mobilized donor progenitor cells collected from the peripheral blood has been associated with a rapid hematopoietic engraftment without an increase in the incidence of acute GVHD compared to allogeneic BMT, an increased donor acceptance, elimination of the risk of general anesthesia and a decreased cost. The use of nonmyeloablative conditioning regimens prior to SCT represents a novel treatment approach that may lead to reduced toxicity and an extended use of this treatment in older patients and those with co-morbid conditions and in the treatment of malignant and non-malignant disorders. This approach may play a role in inducing tolerance for solid organ transplantation and in utilizing the GVM effect to treat solid tumors that are not fully responsive to myeloablative cytotoxic regimens. The optimal intensity of cytoreduction and immunosuppression is not well defined. GVHD and disease recurrence remain a challenge. Promising results have been reported in patients with refractory hematologic malignancies as well as in metastatic renal cell cancer, but the ultimate role of this treatment modality remains to be defined pending prospective, well designed, randomized trials.

Intraportal and systemic allogeneic cell therapy in a murine model of hepatic metastatic breast cancer

Allogeneic immunocompetent splenocytes were tested for their ability to exert a GVT effect in a murine model of liver metastasis. Mammary carcinoma cells originating from an H-2(d) mouse were inoculated through the PV of F(1) (H-2(d/b)) mice, to mimic clinical hepatic involvement in malignant disease. Cell therapy was given either locally (PV) or systemically by IV inoculation to test differential efficacy of the GVT effect, and the differential expression of GVHD symptoms induced by diverse routes of administration. Livers of mice treated with H-2(b) derived splenocytes given PV or IV remained tumor-free for at least 4 weeks following tumor inoculation. Furthermore, all secondary recipients of adoptively transferred (AT) liver cells were tumor-free for >300 days. In contrast, all livers of untreated control mice or mice treated with syngeneic splenocytes displayed tumor metastases as early as 2 weeks following tumor inoculation, and large local tumors developed in AT secondary recipients. Our data demonstrate the efficacy of allogeneic cell therapy, given either locally or systemically, in the eradication of liver metastases. However, diverse routes of cell therapy administration did not show any difference in the expression and outcome of GVHD.

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.

Detection of minimal residual disease by real-time PCR can be used as a surrogate marker to evaluate the graft-versus-myeloma effect after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) is an effective and potentially curative treatment for some cases of multiple myeloma (MM). The curative efficacy of allo-SCT may be largely attributed to its immunological activity, the graft-versus-myeloma (GVM) effect. To evaluate the kinetics of residual myeloma cells, we analyzed the follow-up bone marrow samples of three MM patients by means of a real-time molecular assay. We identified a consistent correlation between onset of graft-versus-host disease and disease response. These data suggest that real-time molecular follow-up can be used to monitor the GVM effect and that it can be employed in the clinical setting to tailor post transplant immunomodulation.

[Nonmyeloablative allogeneic peripheral blood stem cell transplantation of renal cell carcinoma]

We presented three cases with refractory metastatic renal cell carcinomas who underwent nonmyeloablative allogeneic peripheral blood stem cell transplantation(PBSCT). A fludarabine and cyclophosphamide-based regimen was used. Complete donor-T-cell chimerism was established at day 94, 40, 52 after PBSCT in each case. GVHD occurred at day 183, 53, 75. In Case 1 and Case 3 apparent GVT effects reduced the metastases at day 212, 261 and let them live longer than expected. Case 2 died at day 69 before GVT effect appeared, because the case was so-called rapid growth type. Histological examinations in Case 1 and Case 3 showed infiltration of lymphocytes disrupting the foci of renal cell carcinomas which was considered as findings of GVT effects.

[Gastrointestinal cancer]

Ten patients with refractory gastrointestinal cancer received nonmyeloablative allogeneic stem-cell transplantation(NST) from HLA-identical sibling. The conditioning regimen consisted of cyclophosphamide and fludarabine. None of the patients rejected the allograft. Five patients developed grade II-III acute GVHD and 5 patients developed extensive chronic GVHD. Three patients achieved remarkable serum tumor marker regressions after the steroids were discontinued, which were attributed to graft-versus-tumor (GVT) effects. One patient achieved a partial response, and three patients had stable disease. At a median follow up of 155.5 days (52-349), 2 patients are alive and 8 patients died for progressive disease. NST for refractory gastrointestinal cancer was feasible. Although GVT effects against gastrointestinal cancer were observed, the effects were limited for highly progressive disease.

[Mini-transplantation for solid tumors]

With the hypothesis that RIST might be useful to induce immunological antitumor effect without excessive toxicities, we evaluated 27 patients(median age 38 years, range 4-59) with refractory non-renal solid tumors, who underwent RIST from the family donors. The primary and secondary endpoints included achievement of complete chimerism, and exploratory evaluation of graft-versus-tumor(GVT) effect, respectively. The conditioning regimen comprised purine analogue and busulfan with or without antithymocyte globulin. All patients achieved complete donor chimerism. These data demonstrate that RIST is a sufficient way to induce immune competent cells to patients with solid tumors. Although cases experienced probable GVT effect were observed in selective patients, total benefit for each tumor should be carefully evaluated in specific phase II-III trials.

[Allogeneic hematopoietic stem cell transplantation for solid tumors in the United States: a review]

The field of bone marrow transplantation has undergone dramatic changes over the past few decades. Not only has the terminology changed (e.g., hematopoietic stem-cell transplantation), but the role of allogeneic transplantation has been modified from supportive to immunotherapeutic and the applications have expanded from hematologic malignancies to solid tumors. The development of nonmyeloablative conditioning regimen has greatly increased the number of patients eligible for this kind of treatment. Use of hematopoietic stem-cell transplantation as a form of adoptive immunotherapy in the treatment of cancer depends on advances in tumor immunology, particularly the identification of tumor antigens and mechanisms of immunotherapy. The earliest use of allogeneic transplantation of immunogenic cells for the treatment of solid tumors in the late 1960s and early 1970s produced no definite graft-versus-tumor effects. However, as conventional allogeneic hematopoietic stem-cell transplantation methods for the treatment of hematologic malignancies have matured, these methods have reestablished the foundation for expanding their application to solid tumors. From the first case reports on medulloblastoma and breast cancer to subsequent case series reports on breast cancer and renal cell carcinoma, allogeneic hematopoietic stem-cell transplants have demonstrated graft-versus-tumor effect. At present, the most common solid tumor for which this treatment is used is advanced renal cell carcinoma, but allogeneic hematopoietic stem-cell transplants have proven feasible for other solid tumors as well. Directions for future study include the identification of the definitive tumor antigens involved in the graft-versus-tumor effect and means of selecting those patients who will benefit the most from this form of treatment. This review summarizes the peer-reviewed literature on the use of allogeneic transplantation for solid tumors based on US studies.

[The chimerism and GVT effects on murine mini-transplantation model]

We established a murine mini-transplantation model to examine chimerism and graft versus tumor effects(GVT) using with C57BL/6(donor) and(C57BL/6 x BALB/c) (CBF1) (recipient) combination and a IgE producing plasmacytoma cell clone (B53) of BALB/c origin. The chimerism and graft versus tumor effects(GVT) were observed. Two experimental groups were prepared. One is mini-transplantation group (G2): recipients irradiated with 200 rad were inoculated with B53 cells, along with donor cells, the other is bone marrow transplantation group(G4): recipients irradiated with 800 rad were inoculated with B53, along with donor cells. The full chimera was observed one week after transplantation in G4, but that was seen 3 week after transplantation. The GVT effects were observed in both groups. However, GVT effects on G4 is stronger than that on G2 in pathological findings and serum IgE level.

[Immune reconstitution after allogeneic stem cell transplantation using nonmyeloablative or reduced-intensity conditioning regimen]

A number of reduced-intensity conditioning(RIC) regimens, which mainly consisted of potent immunosuppressive agents but not of myeloablative agents, has been explored in order to achieve successful engraftment and subsequent graft-versus-leukemia/tumor effect. Because of the decreased regimen-related toxicity, RIC regimens have replaced myeloablative regimens, particularly for those who are not eligible for high dose chemoradiotherapy due to advanced age or organ dysfunction. However, allogeneic stem cell transplantation(allo-SCT) using RIC regimens sometimes end up with mixed chimerism and may require donor-lymphocyte infusion to achieve complete chimera. Furthermore, strong immunosuppressive agents used in RIC regimens might contribute to the delayed immune recovery after allo-SCT, which might subsequently increase the incidence of infections. These findings suggest that the hematopoietic and immune reconstitution after allo-SCT using RIC regimens is different from that using conventional regimen. In this article, hematopoietic reconstitution, phenotypic analysis of lymphocytes, infections, and graft-versus-host disease after allo-SCT using RIC regimens are discussed, comparing with those using conventional regimens.

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.

Treatment of lymphoma relapses after allogeneic hematopoietic stem cell transplantation with intensive chemotherapy followed by infusion of hematopoietic stem cell from the original donor

Five lymphoma patients relapsed from allogeneic hematopoietic stem cell transplantation (HSCT). Three patients who received myeloablative conditioning had full donor chimerism at relapse, whereas two who received nonmyeloablative conditioning had partially or completely lost the graft. All received mini-BEAM [carmustine (BCNU), etoposide, cytarabine (AraC), melphalan], followed by infusion of HSC (four peripheral blood, one marrow) from the initial donor. Neutropenia and thrombocytopenia were brief, and full donor chimerism was established in all cases. There were four complete and one partial remissions. Graft-versus-host disease occurred in three cases, all with full donor chimerism at relapse. Two patients died subsequently of disease relapse or progression. Another two patients died from fungal infection, one of whom was still in remission at death. One patient had remained in remission 47 months after treatment. Mini-BEAM/HSC is an effective treatment for lymphoma relapses after allogeneic HSCT, but optimal strategies of remission consolidation and prevention of treatment-related complications are needed to improve outcome.

Autoimmune thrombocytopenic purpura after autologous stem cell transplantation

The pathogenesis of thrombocytopenia occurring after autologous stem cell transplantation (ASCT) remains unclear. Six cases of classical peripheral thrombocytopenia that developed after ASCT for non-Hodgkin's lymphoma (NHL) are presented. Resolution of this complication was obtained by usual treatment such as steroids, splenectomy or progressively resolved without specific treatment. Five out of six patients have been followed for more than 5 years after hematopoietic transplantation and are still alive in complete remission despite poor prognostic factors at diagnosis. Several arguments suggest that this phenomenon represents autoimmune thrombocytopenia and may be the consequence of an altered immune balance. Consequently, development of autoimmune reactions after bone marrow transplantation might be associated with an antitumoral effect (graft-versus-lymphoma effect).

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.

High rate of remission and low rate of disease recurrence in patients with multiple myeloma allografted with PBSC from their HLA-identical sibling donors

A total of 30 multiple myeloma patients (M=23, F=7; age 31-55 years, median 48) were allografted with peripheral blood stem cells (PBSC) from HLA-identical siblings. Time to transplantation was 3-107 months (median 8). Prior chemotherapy lines varied from 1 to 6 (median 1). Four patients were in complete remission (CR), 11 in partial remission (PR), 13 were considered to be nonresponders, and two had progressive disease. Most were conditioned with busulfan-melphalan. PBSC were collected by apheresis after G-CSF or sequential GM-CSF and G-CSF. The patients were grafted with 4.4-24.1 x 10(6)/kg CD34+ (median 7.9) and 0.9-7.9 x 10(8)/kg CD3+ cells (median 2.3). GVHD prophylaxis was methotrexate-cyclosporine. Engraftment was complete and rapid. Grades II-IV acute GVHD (aGVHD) developed in 16 (53%), but was grade III-IV only in five (17%); chronic GVHD (cGVHD) developed in 17 out of the 24 evaluable patients (71%). A total of 18 patients (71%) attained CR after transplantation. TRM was 30% overall, 16% at 100 days. There was only one relapse. Overall survival and event-free survival at 73 months were 60% and 67%, respectively. PCR negativity for IgH-gene rearrangement occurred in all persistently CR patients studied. PBSC allograft can induce long remissions, because of profound suppression of the neoplastic clone that is probably linked to the antitumor effect of cGVHD.

'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.

Reduced-intensity transplantation with in vivo T-cell depletion and adjuvant dose-escalating donor lymphocyte infusions for chemotherapy-sensitive myeloma: limited efficacy of graft-versus-tumor activity

Reduced-intensity conditioning regimens allow application of allogeneic stem cell transplantation to greater numbers of patients with myeloma by reducing transplantation-related mortality. We prospectively evaluated the role of an approach incorporating in vivo T-cell depletion and subsequent adjuvant donor lymphocyte infusions (DLIs) as part of front-line therapy for chemotherapy-sensitive multiple myeloma. Twenty patients with HLA-matched related (n = 12) or unrelated (n = 8) donors entered the study. None had previously undergone autologous transplantation. Acute graft-versus-host disease (GVHD) following transplantation was minimal (3 grade II and no grade III or IV). Nonrelapse mortality rate was relatively low (15%) compared with conventional myeloablative allogeneic transplantation series, although it remained significantly higher than in the autologous setting. Disease responses by 6 months posttransplantation were modest (2 in complete remission, 4 in partial remission, 2 were minimally responsive, 6 had no change, 3 had progressive disease, and 3 were not evaluable). Fourteen patients received escalating-dose DLI for residual/progressive disease. Three developed acute GVHD and 2 developed limited chronic GVHD. Seven demonstrated further disease responses, which appeared to be more common in those developing GVHD (5 of 5 versus 2 of 9; P =.02). All responses were associated with conversion from mixed to full donor T-cell chimerism. Response durations were disappointing (5 <12 months) and progression often occurred despite persisting full donor chimerism. Two-year estimated overall survival and current progression-free survival rates (intention to treat with DLI from 6 months) were 71% and 30%, respectively. The current approach incorporating T-cell depletion appears excessively immunosuppressive despite attempts to restore immune function with DLI. Dose escalation failed to allow convincing dissociation of graft-versus-myeloma from GVHD. Attempts to hasten immune reconstitution and to focus and amplify appropriate components of allogeneic T-cell responses will be required to increase complete remission rates and response durations.

Nonmyeloablative allogeneic hematopoietic stem cell transplantation for metastatic breast cancer

Previously, there was very little interest in investigating allogeneic hematopoietic stem cell transplantation (alloHSCT) in breast cancer because of the significant morbidity and mortality associated with this procedure, as well as the disappointing results observed in clinical trials with high-dose chemotherapy and autologous hematopoietic stem cell transplantation in advanced breast cancer. However, the development of nonmyeloablative (reduced-intensity) conditioning regimens, which have less treatment-related mortality but preserve the T cell-mediated graft-versus-tumor (GVT) effect, has led to the investigation of nonmyeloablative alloHSCT in diseases that had not previously been considered for conventional alloHSCT, including metastatic breast cancer. Laboratory data demonstrate that T cell-mediated responses to breast cancer that inhibit tumor growth are possible and provide the rationale to pursue allogeneic adoptive cellular therapy as a strategy to eliminate breast cancer. Early reports of nonmyeloablative alloHSCT indicate that a clinical GVT effect against breast cancer does exist. The responses appear to be dependent on the development of complete donor lymphoid chimerism, and responses may be delayed. The results from these initial trials must be interpreted cautiously. It is unlikely that nonmyeloablative alloHSCT by itself will result in complete eradication of metastatic breast cancer; however, it may serve as a therapeutic platform to enhance the effects of currently available immunotherapies (eg, trastuzumab administration) and complement existing cytotoxic therapies. Well-designed studies will be necessary to determine the clinical efficacy of nonmyeloablative alloHSCT as adoptive cellular therapy in metastatic breast cancer.

Establishment of early donor engraftment after reduced-intensity allogeneic hematopoietic stem cell transplantation to potentiate the graft-versus-lymphoma effect against refractory lymphomas

Reduced-intensity allogeneic hematopoietic stem cell transplantation (alloHSCT), which typically results in mixed chimerism initially after transplantation, has had limited efficacy in chemotherapy-refractory lymphomas. We hypothesized that the rapid establishment of complete donor chimerism would potentiate a graft-versus-lymphoma effect. Fifteen patients with chemotherapy-refractory lymphoma initially received induction with a conventional chemotherapy regimen (etoposide, prednisone, vincristine, cyclophosphamide, adriamycin, fludarabine [EPOCH-F]) to deplete host T cells and provide disease control prior to alloHSCT. Patients then received conditioning with fludarabine and cyclophosphamide followed by alloHSCT from HLA-matched siblings. Graft-versus-host disease prophylaxis consisted of cyclosporine alone. EPOCH-F resulted in 73% of patients having partial responses or stable disease. EPOCH-F depleted host CD4(+) T cells from a median of 235 cells/microL to 56 cells/microL. Fourteen patients underwent alloHSCT, and all had >95% donor engraftment by day 14 after transplantation. The incidence of Grade II to III acute graft-versus-host disease was 71%. There were two therapy-related deaths. There were 8 partial responses and 3 complete responses (CRs) at day 28. Five additional CRs were observed at day 100 without withdrawal of cyclosporine or donor lymphocyte infusion. The rate of CRs for all 15 patients was 60%. The 1-year progression-free survival rate from time of study entry is 67% with only 1 relapse among 9 CRs. At a median potential follow-up of 28 months, the overall survival rate is 53%. These data demonstrate that a potent and durable graft-versus-lymphoma effect can occur against chemotherapy-refractory lymphomas and suggest that this effect may be associated with rapid, complete donor chimerism after reduced-intensity alloHSCT.

Regression of refractory rhabdomyosarcoma after allogeneic stem-cell transplantation

A 17-year-old girl developed refractory rhabdomyosarcoma. An allogeneic peripheral-blood stem-cell transplant was performed after a myeloablative regimen. Although rapid disease progression had resolved transiently, after the start of high-dose chemotherapy, re-progression was apparently observed from day 14. However, delayed tumor regression occurred on day 30, shortly after the reduction of immunosuppressants. She achieved a partial remission. The second tumor regression provides suggestive clinical evidence that graft-versus-tumor effect may occur against rhabdomyosarcoma. Although further investigation is required, allogeneic stem-cell transplantation could provide a new therapeutic option for refractory rhabdomyosarcoma.