Reduced-intensity Conditioning Stem Cell Transplantation Research Articles

Tacrolimus and Sirolimus without Methotrexate as Acute GVHD Prophylaxis after Matched Related Donor Reduced Intensity Conditioning (RIC) Stem Cell Transplantation (SCT).

We have previously shown that the combination of tacrolimus and sirolimus (TAC/SIR) without methotrexate (MTX) is a safe and effective regimen for GVHD prophylaxis after myeloablative SCT. However, TAC/SIR has not been investigated in the RIC setting. We hereby report a prospective phase II trial testing TAC/SIR as GVHD prophylaxis after RIC SCT from matched related donors (MRD). All patients received fludarabine (FLU) 30 mg/m2 IV and intravenous busulfan (BU) 0.8 mg/kg IV daily × 4 days (day -5 thru day -2) as conditioning, followed by transplantation of filgrastim mobilized peripheral blood stem cells. Filgrastim 5 mcg/kg SC QD was started on day +1 until neutrophil engraftment. Tacrolimus and sirolimus were started on day-3, and doses were adjusted to maintain target serum trough levels 5–10 ng/ml and 3–12 ng/ml, respectively. Twenty-six patients have been transplanted, with a median age of 52 years (range 29–64 yrs). Diagnoses include NHL (8), AML (6), HD (5), CLL/SLL (3), CML (2), MDS (1), MM (1). Median CD34+ cells infused was 8.06 × 106 cells/kg (range: 2.96–38.0 × 106 cells/kg). All patients had sustained hematologic engraftment. Only 4 (15%) patients developed neutropenia below ANC 500, and 6 (23%) had platelet counts below 20K. One patient had late graft failure at 7 months post transplant. Grade II-IV acute GVHD incidence was 20%, with grade III-IV incidence of 12%. No hepatic VOD or thrombotic microangiopathy was observed. Day +100 transplant related mortality (TRM) was 0%. The cumulative incidences of TRM and relapse at 1 year were 4% and 38%, respectively. The cumulative incidence of chronic GVHD at 1 year was 74%. A high level (>90%) of donor-derived hematopoiesis was achieved in 68% by 1 month post transplant. Median donor chimerism at between day 20–50 post transplant was 93.5% (range 32%-99%), and 94% (range 22%-100%) at day 85–115. With a median follow-up of 13.5 months among survivors (range 5.5–19 months), progression-free survival (PFS) and overall survival (OS) at 1 year were 58% and 79%, respectively. Compared to a historical cohort of 47 MRD transplant recipients treated with the same FLU/BU conditioning regimen and using TAC/SIR ± mini-MTX (5 mg/m2 IV day +1,3,6) as GVHD prophylaxis, there was no statistical difference between TAC/SIR vs. TAC/SIR/MTX in the incidence of grade II-IV acute GVHD (20% vs 11%, p= 0.48), cumulative incidence of relapse at year (38% vs. 57%, p= 0.25), 1-yr PFS (58% vs. 41%, p= 0.33), or 1-yr OS (79% vs. 73%, p= 0.79). These results demonstrate that omission of mini-MTX is permissible, and that the combination of TAC/SIR alone as GVHD prophylaxis following reduced intensity conditioning with FLU/BU is associated with low rates of acute GVHD, TRM, and high levels of donor chimerism after MRD SCT.

Reduced-Intensity Conditioning Is Associated with Shorter Duration of Chronic GVHD Than Myeloablative Conditioning and Provides Very Good Quality of Life for Long-Term Survivors after Allogeneic Stem Cell Transplantation.

Reduced-intensity conditioning (RIC) has been increasingly used over the last decade as a curative approach for patients (pts) not eligible for myeloablative (MA) conditioning. It is now established that RIC can allow consistent engraftment and reduce toxicity of allogeneic stem-cell transplantation (SCT). However, the long-term effects, and in particular the duration of immunosuppressive therapy (IST) needed and quality of life of long-term survivors are less defined. To explore these issues we analyzed the results of 48 pts given SCT with RIC from 1/2000 to 8/2002, such that survivors have at least 5 year follow-up, and compared them to results of 41 SCT with MA conditioning given during the same period. The RIC group included older pts than the MA group, median age 49 (range, 20–65) and 37 (range, 20–65), respectively (p=0.01). The MA group included more pts with acute leukemia/MDS (68% vs 33%, p=0.001) while pts with myeloma were only given RIC (31% of the RIC group, p< 0.001). 48% of pts in the RIC group had a prior autologous SCT compared with none in the MA group (p< 0.001). There was no difference in donor type, 26% of all pts were given SCT from unrelated donors. After a median follow-up of 6.1 years (range, 5.1–7.6) 40 pts are alive, 20 after RIC and 20 after MA conditioning with estimated survival of 42% (95ci, 28–56) and 47% (95ci, 31–63), respectively (p=NS). Long-term survival with RIC was achieved across all diagnoses including 6 of 16 pts with acute leukemia/MDS, 6 of 6 pts with CML, 3 of 11 pts with lymphoid malignancies and 5 of 15 pts with myeloma. The corresponding rates for acute leukemia/MDS, CML and lymphoid malignancies in the MA group were 13 of 28, 3 of 4 and 4 of 9, respectively. Chronic GVHD occurred in 22 pts after RIC and in 26 pts after MA conditioning with a cumulative incidence of 48% (35–65) and 66% (53–83), respectively (p=0.07). 12 of 22 pts with chronic GVHD after RIC were eventually able to stop IST, 9 died on IST (relapse-5, non-relapse mortality (NRM)-4) and only 1 of 20 long-term survivors was still on IST at last follow-up. The median duration of IST was 17 months and the cumulative probability of stopping IST after 5 years (with relapse been competing risk) was 79%. In the MA group 10 of 26 pts with chronic GVHD were able to stop IST, 8 died on IST (relapse-6, NRM-2) and 8 of 20 long-term survivors were still on IST at last follow-up. The median duration of IST was 41 months (p=0.05) and the cumulative probability of stopping IST after 5 years was 48% (p=0.001). Two women gave birth in the RIC group while 2 men in the MA group fathered children spontaneously. There was one secondary malignancy in the MA group and none in the RIC group. Two pts in the MA group sustained myocardial infarction (one fatal) compared to none of the RIC group. One pt in the RIC group had reversible nephrotic syndrome. In summary long term(>5y) survival is similar for both RIC and MA SCT, however IST is significantly shorter after RIC and quality of life seems better. Overall, all 20 pts surviving more than 5 years after RIC SCT sustained excellent quality of life and only one still required IST. The more rapid achievement of transplantation tolerance with RIC may relate to better preservation of thymic function, but this requires further investigation. These observations require further confirmation in larger registry studies.

Successful treatment of lymphoproliferative disease complicating primary immunodeficiency/immunodysregulatory disorders with reduced-intensity allogeneic stem-cell transplantation

AbstractLymphoproliferative disease (LPD) is a recognized complication of primary immunodeficiency (PID) and immunodysregulatory syndromes. Historically, it has a very poor outcome. For patients surviving LPD, myeloablative hematopoietic stem cell transplantation (SCT) was the only cure for the underlying PID, with a high risk of developing posttransplantation complications, including recurrent lymphoproliferative disease. We describe 8 patients with a range of PID and immunodysregulatory syndromes complicated by LPD. After initial treatment of the LPD (including the use of anti-CD20 monoclonal antibody, rituximab, in 6 of the patients), all patients underwent reduced-intensity conditioning (RIC) SCT with prospective monitoring for Epstein-Barr virus (EBV) viremia. After transplantation, 3 patients received rituximab, and 3 patients received prophylactic EBV-specific cytotoxic T-lymphocytes. Only 1 patient developed recurrent LPD posttransplantation, which responded to rituximab. All patients who underwent transplantation survive free of LPD and are cured of their PID at a median follow-up of 4 years (range, 1-7 years). With careful monitoring and pre-emptive therapy, we advocate this RIC SCT approach to patients with PID who have pre-existing EBV-LPD.

Chimerism analysis within 6 months of allogeneic stem cell transplantation predicts relapse in acute myeloid leukemia

The role of chimerism analysis as a prognostic indicator of relapse after hematopoietic stem cell transplantation (SCT) is controversial. We monitored chimerism status by short tandem repeat-based polymerase chain reaction (PCR) in T- and non-T-cell subsets and retrospectively evaluated clinical outcome in 96 patients with acute myeloid leukemia after myeloablative (MA) or reduced-intensity conditioning SCT. Fifty-six percent of 80 patients in the MA group demonstrated complete donor chimerism (CC) at all time points, whereas 6% had decreasing mixed chimerism (MC), 8% stable MC, 25% increasing MC and 3% increasing and decreasing MC. In 16 RIC patients, these percentages were 12, 50, 6, 6 and 19, respectively, together with 6% nonengraftment. Forty-three out of 96 patients experienced relapse. The last chimerism evaluation before relapse revealed increasing MC in only eight patients. In samples taken between 1 and 6 months post SCT, CC/decreasing MC was significantly related with a lower risk of relapse (31 versus 83%, P<0.000) and mortality (38 versus 83%, P<0.000) than with MC/increasing MC. However, the development of relapse was very rapid. Only very frequent monitoring of chimerism status by highly sensitive methods might identify impending relapse and allow early immunological intervention.

A Pilot Study of Reduced-Intensity Conditioning Stem Cell Transplantation with T-Cell Replete HLA-Mismatched Allograft from Child to Parent Patient for the Treatment of Refractory Adult T-Cell Leukemia.

[Background/Purpose] Adult T-cell leukemia (ATL) is a most aggressive lymphoid malignancy with poor prognosis, and at present, allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been an only curative modality. Nevertheless, not only the aggressive nature of disease itself, but also the aging of patients older than 55 y.o. contribute to therapeutic impediments by comorbidity and difficulty of timely acquiring HLA-matched sibling donor. In this setting, allograft from child to parent patient is a realistic modality. We report a result of a prospective study evaluating the efficacy of reduced -intensity conditioning SCT (RIST) with HLA-mismatched allograft from child to parent for ATL patients.[Patients/methods] 5 patients (2 males, and 3 females) with ATL in progressive disease (PD) after induction chemotherapy with LSG15 regimen who had no HLA-identical sibling donors were enrolled. Patient median age was 59 y.o. All donors were sons with haploidentical HLA. Median age of donor was 29 y.o. KIR ligands were matched. Preparatory regimen consisted of fludarabine (180mg/m2), busulfan (8mg/m2) or cyclophosphamide (120mg/kg) and rabbit antithymocyte globulin (2.5mg or 5.0mg/kg). Stem cell source was G-CSF mobilized PBSC. Mean infused CD34 cell number was 8.3×106/kg (from 4.1 to 23.3 × 106/kg). GVHD prophylaxis consisted of tacrolimus or cyclosporine and short term methotraxate and mycophenolate mofetil.[Results] Median interval from induction chemotherapy to transplantation was 5 months. Median observation interval was 8 mo. (from 3.5 mo. to 31 mo.). All 5 cases had neutrophil engraftment at day 15 after transplantation. In 5 of 5 cases, complete donor T-cell chimerism were obtained by day 30. Overall survival (OS) and progression free survival (PFS) at 1 year was 50%, and 26.7%, respectively. Evaluation of peripheral residual disease demonstrated by HTLV-I proviral load and soluble interleukin-2 receptor (sIL-2R) value documented the strong disease suppression by this transplants. Analysis of NK cell kinetics revealed that donor-derived NK cells expanded and exerted killing activity mainly until 4 months after transplantation, and decreased in number thereafter. These findings indicated all achieved complete donor T-cell chimerism followed by clinical observations for graft vs. ATL effect. Although, disease progression occurred 4 of 5 cases, 2 achieved remission again with the longest response duration of 31 mo. All but UPN2 experienced GVHD (grade 2 to 4), and UPN2 had early relapse and died of ATL at 4 mo. after allo-HSCT. Frequent reactivations of cytomegalovirus were observed, but well controlled by ganciclovir.[Summary] In our pilot study, RIST with T-cell replete HLA-mismatched allograft from child to parent patient could provide timely donor acquisition and durable remission for all patients with refractory ATL. This setting may be one of realistic modalities for ATL patients who need alternative donors.

Long-Term Follow-Up of Allogeneic Stem Cell Transplantation (SCT) with Reduced Intensity Conditioning (RIC) for Patients (pts) with Chronic Myeloid Leukemia (CML).

Allogeneic SCT remains an effective strategy for inducing durable remission in CML. RIC regimens are less myelosuppressive, but adequately immunosuppressive, allowing for engraftment with acceptable treatment-related mortality (TRM) in older pts who otherwise would not be candidates for SCT. The long-term antitumor effect of this approach is not well-established. This is relevant in CML, since many pts present for SCT with advanced disease after failing tyrosine kinase inhibitors (TKI).Patients, Methods: We evaluated outcomes of 64 CML pts (40 M/24 F) with median age 52 yrs (range 18–72) treated from June 1996 to April 2005 with FAI (fludarabine 120 mg/m2, Ara-C 8 gm/m2, idarubicin 36 mg/m2), FM140 (fludarabine 120 mg/m2, melphalan 140 mg/m2 +/− Ara-C 2 gm/m2) or FM180 (fludarabine 120 mg/m2, melphalan 180 mg/m2) and unmanipulated stem cells. Disease stage at time of study entry was first chronic (n=13), second chronic (n=17), accelerated (n=29), or blast phase (n=5), with median time from diagnosis to SCT of 2.6 yrs (range 0.5–20.3). Stem cell source was bone marrow (n=38) or peripheral blood (n=26), and donor type was matched related (n=30), 1 Ag mismatched related (n=4), or matched unrelated (n=30). Graft vs. host disease (GVHD) prophylaxis consisted of tacrolimus and mini-dose methotrexate in all but 6 pts (CSA-based).Anti-thymocyte-globulin was added to all pts other than matched related. Maintenance therapy with TKIs following SCT was not used. Multivariate analysis was done using Cox proportional hazards regression.Results: 22 pts were alive at a median follow up of 7 yrs from SCT (range 0.8–9.8). OS and PFS were 48% and 30%, respectively, at 2 yrs, and 33% and 30%, respectively, at 5 yrs. The cumulative incidence of acute GVHD grades II–IV and III–IV were 31% and 14%, respectively, and chronic GVHD was 32% (22% for extensive). TRM at 100 days, 1-, 2-, and 5- yrs were 2%, 14%, 20%, and 33%, respectively. There was no association between pt age, donor source, preparative regimen, or time to SCT and TRM. Disease recurrence accounted for 12 of 42 deaths. There were 3 cases of graft rejection, with 1 death from graft rejection. Only disease stage at time of SCT was significantly predictive in multivariate analysis for both OS and PFS. Pts with advanced disease had worse OS (HR 2.36, 95%CI 1.25–4.46, p=0.008, see figure) and PFS (HR 1.91, 95%CI 1.05–3.49, p=0.035) than pts in chronic phase. In multivariate for PFS, pts who developed grade I or II acute GVHD were less likely to progress compared to pts who did not develop any GVHD: grade I (HR 0.324, 95%CI 0.13–0.84, p=0.027) and grade II (HR 0.286, 95%CI 0.11–0.78, p=0.014).Conclusion: RIC SCT provides adequate disease control in chronic phase CML pts. The development of some GVHD is protective in this setting. TRM rates are acceptable but continue to increase over time. Alternative treatment strategies need to be explored in pts with accelerated or blast phase disease. Results may be improved with addition of TKI therapy post SCT. [Display omitted]

Long-Term Follow-Up of Allogeneic Stem Cell Transplantation for Chronic Lymphocytic Leukemia.

IntroductionAllogeneic stem cell transplantation (Allo-SCT) remains an option for patients with chronic lymphocytic lymphoma (CLL). Our program employs a strategy using allo-SCT for patients (pts) with high risk disease based on clinical characteristics and prior therapy. We performed a retrospective analysis to examine long-term disease control and treatment toxicity.MethodsA total of 52 patients (pts) are included who underwent allo-SCT at our institution between Aug 1989 and Dec 2005. Patients were in a chemosensitive remission at the time of SCT. The conditioning regimen consisted of busulfan (1 mg/kg PO q6h X4 days between 1989–200 and 3.2 mg/kg IV daily X 4days subsequently) and cyclophosphamide 60 mg/kg X 2 days. Cyclophosphamide 60 mg/kg X 2 days and TBI 12 Gy was used for unrelated donor SCT. Reduced intensity conditioning (RIC) SCT were typically performed with Fludarabine 50 mg/m2 for 4 days and 2 Gy TBI. GVHD prophylaxis was with cyclosporine A and methotrexate.ResultsThere were 34 males and 18 females. The median age at the time of transplant was 51 years (range 26 to 65). Histologic subtype was: CLL and/or small lymphocytic lymphoma (SLL); 48 and T-prolymphocytic leukemia (PLL): 4. The median number of prior chemotherapy regimens was 3 (range 1 – 10) and was unavailable in 16. Prior chemotherapies included: anthracycline-based: 24, prior purine analog: 32, prior platinum-based: 8, prior auto-SCT: 1, prior rituximab: 5. The median time from diagnosis to allo-SCT was 58 months (range 5 – 260). 10 pts underwent RIC SCT. Graft source was: matched sibling (MSD) bone marrow (BM): 18, MSD peripheral blood stem cells (PBSC): 20, Mismatch related (MMRD) bone marrow (BM): 1, MRD PBSC: 4, matched unrelated donor (MUD) BM: 8, MUD PBSC: 1. At 5 years, the overall survival of the entire cohort is 51% (95% confidence intervals: 34 – 68%) with two long-term survivors of 14 and 17 years. Treatment-related mortality (TRM) was 20 of 52 pts (38%). 4 pts have relapsed ((8% of total cohort) and non-relapse mortality was 1 pt (2%). Overall survival by intensity of SCT conditioning regimen was not significant (p=0.3). TRM was similar in pts who received fully myeloablative SCT (40% vs. 20% in RICSCT group, p=0.29).ConclusionsAcceptable survival post-SCT is possible using an allo-SCT strategy in CLL. However, TRM remains high in this group of heavily pre-treated patients with a median age of over 50 that predominantly received fully myeloablative allo-SCT. Due to small sample size, the potential benefit of reduced TRM with RICSCT cannot be demonstrated. Ideally, allo-SCT should be considered earlier in the course of the disease based on risk stratification utilizing traditional risk factors and modern prognostic factors such as FISH studies and novel markers.

Stem cell transplantation with reduced-intensity conditioning for hemophagocytic lymphohistiocytosis

AbstractAllogeneic stem cell transplantation (SCT) is curative for hemophagocytic lymphohistiocytosis (HLH). However, patients frequently have significant morbidity before transplantation and there is high transplant-related mortality (TRM). Because first-degree HLH is caused by immune dysregulation, a reduced-intensity conditioned (RIC) regimen might be sufficient for cure while decreasing the TRM. Twelve patients with HLH underwent RIC SCT from a matched family/unrelated or haploidentical donor. Eleven were conditioned with fludarabine/melphalan with additional busulphan for haploidentical grafts. One received fludarabine and 2-Gy total body irradiation (TBI). All patients showed engraftment at a median of 14 days. Nine of 12 (75%) are alive and in complete remission (CR) a median of 30 months (range, 9-73 months) after SCT. Two patients died from pneumonitis and one from hepatic rupture. Four patients developed acute graft-versus-host disease (GVHD) and 3 have chronic GVHD. Three of 9 survivors have mixed chimerism but remain free of disease. In summary, RIC compares favorably to conventional SCT with long-term disease control in surviving patients despite a significant incidence of mixed chimerism.

Reduced-Intensity Conditioning (RIC) Followed by Allogeneic Stem Cell Transplantation (SCT) for Relapsed Lymphomas: Impact of Pre-Transplantation Factors on Long-Term Outcome.

Allogeneic stem cell transplantation (SCT) represents a potentially curative treatment for recurrent lymphoid malignancies. In fact, potential advantages include the use of a tumor free graft and immune-mediated graft-versus-lymphoma effect. Here, we analyzed the impact of pre-transplantation factors on outcome in 141 lymphoma patients (pts) receiving RIC and allogeneic SCT from HLA-identical sibling donors. Histologic types included in the study were: low-grade non-Hodgkin lymphoma (LG-NHL; n=58), high-grade NHL (HG-NHL, n=55), Hodgkin disease (HD; n= 28). Median age was 50 years (range: 20–69). The three groups (HD vs LG-NHL vs HG-NHL) had similar characteristics in terms of: chemosensitive disease (57% vs 69% vs 67%, p=ns) and complete remission (CR) at transplant (18% vs 27% vs 34%, p=ns). Pts with HD had received more lines of chemotherapy (>2 vs ≤2) as compared to LG-NHL and HG-NHL (82% vs 52% vs 42%). Furthermore, the proportion of pts receving previous autologous SCT was significantly higher in HD and HG-NHL versus LG-NHL (75% vs 54% vs 27%). In addition, patients with HG-NHL and HD underwent frequently allo-SCT less than 2 years after diagnosis as compared to LG-NHL (58% vs 39% vs 24%). All patients received debulkying chemotherapy followed by the same RIC containing thiotepa (10 mg/kg), fludarabine (60 mg/ms) and cyclophosphamide (60 mg/kg). GVHD prophylaxis consisted of cyclosporine A and short-course methotrexate. At a median follow-up of 30 months (8–70), the overall survival (OS) and progression-free survival (PFS) were 65% (95%CI, 56–74%) and 57% (95%CI, 47%–67%), respectively. Univariate analysis showed that age (< or > 55 years), donor sex, interval between diagnosis and SCT, number of previous treatments did not influence outcome whereas diagnosis of HD was associated with a significant inferior PFS and OS. Chemosensitive disease (CR+PR) influenced PFS in HG-NHL (p<0.0003) and HD (p<0.0036) but not in LG-NHL (p=0.69). Complete remission at transplant was associated to a significant better PFS in HD (p<0.01) but not in HG-NHL (p= 0.14) and LG-NHL (p=0.7). Previous autologous SCT was associated to inferior PFS (64% vs 50%, p<0.04) but did not affected OS and TRM. By multivariate analysis, diagnosis of HD and refractory disease were associated to an inferior PFS (p<0.0001, p<0.001) whereas diagnosis of HD and no-CR at transplant remained of prognostic value on OS (p<0.006 and p<0.007). We conclude: 1) age and previous treatments, including autologous SCT, are no longer limitations for allogeneic SCT; 2) debulking therapy before RIC allogeneic SCT is required for HD and HG-NHL; 3) new strategies for an early indentification of chemorefractory pts are necessary.

Case of a Patient with Progressive Adult T-Cell Leukemia/Lymphoma Treated Successfully by Reduced-Intensity Conditioning Stem Cell Transplantation from an HLA-Incompatible Related Donor

A 61-year-old man with progressive adult T-cell leukemia/lymphoma (ATLL) successfully received reduced-intensity conditioning stem cell transplantation (RIST) without T-cell depletion (TCD) from his HLA-incompatible son, who had negative results for human T-lymphotropic virus type 1 (HTLV-1) (1-locus, 1-allele mismatch in the graft-versus-host [GVH] direction; 2-loci, 1-allele mismatch in the host-versus-graft direction). The preparatory regimen consisted of fludarabine, busulfan, and rabbit antithymocyte globulin. GVH disease (GVHD) prophylaxis consisted of short-term administration of methotrexate, tacrolimus, and methylprednisolone. The patient achieved complete donor chimerism on day 30 after transplantation. On approximately day 50 the patient started to experience steroid-refractory skin GVHD (grade IV), which was successfully managed with basiliximab (anti-CD25 monoclonal antibody) and mycophenolate mofetil (MMF). Serial analysis of HTLV-1 proviral load by quantitative polymerase chain reaction analysis using whole peripheral blood demonstrated undetectable levels from day 90. At the time of this writing the patient had been in complete remission for more than 16 months. The results in this case suggest the potential of non-TCD RIST from an HLA-incompatible relative donor as an alternative source of hematopoietic stem cells even for an elderly patient with advanced ATLL. In addition, basiliximab combined with MMF may be effective for the treatment of steroid-refractory skin GVHD without deteriorating the graft-versus-ATL effect.

Cytomegalovirus (CMV) infections and CMV-specific cellular immune reconstitution following reduced intensity conditioning allogeneic stem cell transplantation with Alemtuzumab

We studied the incidence and recurrence of Cytomegalovirus (CMV) infection and reactivation in 38 recipients of Alemtuzumab reduced intensity conditioning-stem cell transplantation, and used CMV-HLA tetramer studies to discover if these events correlated with recovery of circulating CMV-specific CD8+ T cells (cytotoxic T lymphocyte (CTLs)). The cumulative incidence of CMV infection was 60% at 1 year (95% CI, 45-78%) with a median reactivation time of 24 days (range 5-95 days). All patients with CMV reactivation received Ganciclovir or Foscarnet, and only one developed CMV disease. More strikingly, only 8/21 patients had relapse of CMV antigenemia. Tetramer analysis in 13 patients showed that 11 reconstituted CMV CTLs (7/11 by day 30 and 10/11 by day 90). The development of CMV infection was accompanied by a >5-fold rise of CMV CTLs. Recurrence of CMV infection occurred only in the patients who failed to generate a CTL response to the virus. Hence, recipients of SCT using Alemtuzumab-RIC are initially profoundly immunosuppressed and have a high incidence of early CMV reactivation. However, in the majority of patients, infection is transient, and antiviral T cell reconstitution is rapid. Monitoring with CMV-specific CTLs may help identify the subset of patients at risk from recurrent infection or disease.

Impact of human leucocyte antigen mismatch on graft‐versus‐host disease and graft failure after reduced intensity conditioning allogeneic haematopoietic stem cell transplantation from related donors

The impact of human leucocyte antigen (HLA) incompatibility between donor and recipient on graft-versus-host disease (GVHD) and graft failure after reduced-intensity conditioning stem cell transplantation (RICT) remains to be elucidated. We retrospectively analysed outcome in 341 patients who underwent RICT from related donors for haematological malignancies. The overall cumulative incidence of grade II-IV acute GVHD (aGVHD) was 40% for all subjects; 39% in recipients with HLA-matched donors, 44% in those with one-locus-mismatched donors, and 50% in those with two- to three-loci-mismatched donors. In a Cox regression model adjusted for potential confounders, the tendency for grade II-IV aGVHD (P=0.01), chronic GVHD (cGVHD) (P=0.05) and graft failure (P=0.033) increased with HLA disparity. Use of peripheral blood grafts instead of marrow was a risk factor for cGVHD. Use of antithymocyte globulin was associated with reduced aGVHD and cGVHD. Overall survival (OS) in recipients of two- to three-loci-mismatched RICT at 2 years (18%) was significantly worse than that in patients who received one-locus-mismatched RICT (51%) and HLA-matched RICT (48%) (P<0.0001). A two- to three-loci mismatch was identified as an independent risk factor for OS (P<0.001), but there was no significant difference in OS between HLA-matched and one-locus-mismatched RICT. HLA incompatibility between the donor and recipient is an important risk factor for graft failure, aGVHD, cGVHD and OS after RICT. RICT from a one-locus-mismatched donor may represent an effective alternative approach in patients with high-risk malignancies who lack HLA-matched related donors.

Engraftment of Allogeneic Hematopoietic Stem Cells Requires Both Inhibition of Host-Versus-Graft Responses and ‘Space' for Homeostatic Expansion

The establishment of host-versus-graft (HvG) tolerance is the primary aim of reduced intensity conditioning (RIC) regimens for allogeneic stem cell transplantation (SCT). It remains to be clarified to what extent recipient myeloablation is fundamental in the establishment of donor chimerism. We have addressed this question in a murine model of RIC SCT in which the donor-recipient combination produces HvG against the male specific minor histocompatibility antigen HY. In this system engraftment can be monitored by RT-PCR and HvG effectors enumerated by tetramer analysis. We demonstrate that the dose of irradiation influences donor hemopoietic engraftment and affects generation of anti-donor specific T cells. Chimeric recipients do not mount a HvG immune response, becoming selectively tolerant, as demonstrated by the long term acceptance of skin grafts of donor but not third party origin. However, HvG tolerance is not sufficient to secure engraftment since, even in the absence of HvG, partial myeloablation was still required. The "space" produced by myeloablation and the consequent potential for donor cell expansion could also affect HvG tolerance, since its induction is severely impaired when donor hematopoietic cells have reduced proliferative capacity. We conclude that both some degree of myeloablation and HvG tolerance are required for successful engraftment, and that the capacity of donor cells to proliferate influences the induction of HvG tolerance.

Retrospective Multicenter Study of Allogeneic Peripheral Blood Stem Cell Transplantation Followed by Reduced-Intensity Conditioning or Conventional Myeloablative Regimen

This retrospective study compared the results of reduced-intensity conditioning stem cell transplantation (RIST) and a conventional myeloablative regimen (CST) followed by allogeneic peripheral blood stem cell transplantation. In this respect, 63 RISTs and 41 CSTs were performed at 5 transplantation centers in Korea between April 1998 and December 2002. The RIST group had more adverse pretransplant characteristics. More aggressive diseases, like acute myeloid or lymphoblastic leukemia, were included in the CST group, while the RIST group included more indolent diseases, like chronic myeloid leukemia or myeloma (p < 0.001). The incidence of acute graft-versus-host disease (GVHD) grades 2–4 was 29.1 and 57.9% for the RIST and CST groups, respectively (p = 0.010), yet the incidence of chronic GVHD was similar in the two groups (57.4 vs. 71.9%). With a median follow-up of 13 months (0.5–61 months, 17 months in 52 survivors), the 3-year overall (OS) and disease-free survival (DFS) was similar in the RIST and CST groups (p = 0.965 for OS, p = 0.545 for DFS). In a multivariate analysis, RIST (p = 0.010), good performance status (p = 0.006) and a higher CD34+ cell dose (p = 0.008) were all identified as independent favorable prognostic factors for OS. Accordingly, in the current study, RIST produced equivalent or acceptable results compared with CST in terms of OS. Therefore, a prospective randomized trial of RIST and CST is warranted.

High Incidence but Low Morbitiy of Early Cytomegalovirus (CMV) Infections Following Reduced Intensity Conditioning (RIC) Allogeneic Stem Cell Transplantation with Alemtuzumab and Ganciclovir Prophylaxis.

Background: IThe CD52 monoclonal antibody Alemtuzumab appears to be of great promise when incorporated as a lymphocyte depleting agent in RIC stem cell transplants. However the degree of functional immunosuppression produced by this antibody in this application has not yet been well characterized. As a surrogate functional marker, we have studied the incidence and pattern of CMV infection following RIC transplantation regimens with a regimen incorporating this antibody.Methods: We analyzed CMV infections and risk factors in 49 patients who underwent allogeneic stem cell transplantation with a RIC regimen consisting of Fludarabine (120mg/m2), total body irradiation (450 cGy), antithymocyte globulin (40mg/kg), (n=11) or Alemtuzumab (40mg), (n=38) with or without CD45 monoclonal antibodies for various malignant disorders. Donors were HLA identical (related, n=20; unrelated, n=20) or one antigen mismatched (n=9). Ganciclovir was used as prophylaxis starting at engraftment or on recovery from cytopenias. CMV antigenemia and polymerase chain reaction based assays were performed on peripheral blood twice a week till day 100 and then on each clinic visit.Results: The cumulative incidence of CMV reactivation at 1 year post-transplant with Alemtuzumab, in patients at risk, was 60% (95% CI, 45%–78%). Median time to reactivation of 24 days (range, 5– 95 days). Fifty seven percent (12/21) of the reactivations occurred before day 30. Recurrence of CMV reactivation occurred in 38% (8/21) of patients with a median number of recurrences of 2 (range, 1–6) and they extended beyond day 100. Only one patient developed CMV colitis and fully recovered with treatment. There was no CMV related mortality. The overall non-relapse mortality was 16% and overall survival in CMV reactivators and non-reactivators was not statistically different. Risk factors for CMV reactivation analyzed were patients age, sex, acute graft vs host disease, Alemtuzumab use, Ganciclovir use before day 30 and absolute lymphocyte count at day 30. In univariate analysis, use of Alemtuzumab (P= 0.001) and starting Ganciclovir after day 30 (P= 0.002) were significantly associated with CMV reactivation but in multivariate analysis only starting Ganciclovir after day 30 was statistically significant, P= 0.009 (95% CI, 1.5%–17%).Conclusions: RIC stem cell transplantation using Alemtuzumab is associated with a particularly high incidence of early CMV reactivation, and is also associated with recurrent reactivation extending beyond day 100. Although the incidence of CMV disease was low, the high frequency of viral reactivation with Alemtuzumab is likely an indicator of profound post transplant immune suppression, suggesting that despite the “reduced intensity” of the conditioning, these patients require early, comprehensive and prolonged pre-emptive/prophylactic therapy for opportunistic infections.

Reduced-Intensity Conditioning (RIC) Followed by Allogeneic Transplantation in Relapsed Lymphomas: Evidence for Graft-Versus-Lymphoma Effect in Low and High Grade Histologies, but Not in Hodgkin Disease.

Reduced intensity conditioning (RIC) followed by allogeneic stem cell transplantation (SCT) is associated with durable engraftment, low transplant-related mortality (TRM) and clinical remissions in hematologic malignancies. In addition, RIC followed by allograft is feasible also in patients who had failed previous autologous (auto) SCT. Here, we report the outcome of 118 lymphoma pts receiving RIC and allogeneic SCT from HLA-identical sibling donors. Histologic types included in the study were: chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; n=26), low-grade non-Hodgkin lymphoma (LG-NHL; n=24, 21 follicular NHL), high-grade NHL (HG-NHL, B cell n=28, T cell n=17), Hodgkin disease (HD; n=23). Median age was 50 years (range: 20–69). 47% of pts had refractory disease (46% CLL/SLL; 33% LG-NHL; 44% HG-NHL; 56% HD) and 48% have failed an auto SCT (15% CLL/SLL; 33% LG-NHL; 55% HG-NHL; 82% HD). All pts received debulkying chemotherapy followed by the same RIC regimen with thiotepa (10 mg/kg), fludarabine (60 mg/ms) and cyclophosphamide (60 mg/kg). GVHD prophylaxis consisted of cyclosporine A and short-course methotrexate. All pts engrafted. De-novo acute GVHD developed in 43% of pts and chronic GVHD in 45%. The 2-year TRM rate was 13% and was not influenced by previous auto SCT or hystological type. At a median follow-up of 20 months (range, 6–62 months), 91 pts (77%) are alive (n=69 CR, n=8 PR, n=14 with disease) and 27 died (23%) for disease (n=17) or TRM (n=10). The 2 years PFS rates for CLL/SLL, LG-NHL, HG-NHL, HD were 63%, 78%, 64%, 16%, respectively. Chemorefractory disease at time of SCT was associated with a worse 2-year PFS compared to chemosensitive disease (41% versus 74%, p<0.001). There was a trend toward lower relapse risk for pts developing acute or chronic GVHD (37% versus 50%, p=0.2). The 2-year OS rates for CLL/SLL, LG-NHL, HG-NHL, HD were 77%, 90%, 76%, 56%, respectively. Chemosensitive disease had significant impact on OS (84% 2-year OS compared with 64% for chemorefractory patients; p< 0.007) as well the occurrence of chronic GVHD (87% versus 57%; p<0.0059). Interestingly, previous auto SCT and age > 55 years did not influence OS. Among pts in clinical CR, 24 were suitable for PCR monitoring of residual disease and 17 pts (71%) are in continuous molecular remission. Our study indicates: 1) low TRM in a multicenter phase II study; 2) low risk of relapse and good survival rates in indolent lymphomas; 3) encouraging results in HG-NHL 4) disappointing results in HD

Non‐T‐cell‐depleted HLA‐haploidentical stem cell transplantation after reduced‐intensity conditioning in advanced haematological malignancies based on feto‐maternal microchimerism

Long-term feto-maternal microchimerism suggests that immune tolerance exists between mother and child. Based on this hypothesis, we have previously demonstrated that haploidentical stem cell transplantation (SCT) is possible without Tcell depletion (TCD) between non-inherited maternal antigen (NIMA)-mismatched family members (Shimazaki et al, 2003). Recently, reduced-intensity conditioning stem cell transplantation (RIST) has been developed and was applicable for patients who could not undergo conventional high-dose chemoradiotherapy because of their age or organ dysfunction (Giralt et al, 2001). However, the issue of whether RIST from a human leucocyte antigen (HLA)-haploidentical related donor is feasible remains unknown. We therefore examined whether RIST could be performed without TCD in HLA-haploidentical SCT between NIMA-mismatched family members. Six patients with haematological malignancies were included in this study (Table I). There were two males and four females, whose ages ranged from 24 to 62 years. All patients but one were in a refractory stage. The mother served as donor in one patient, a child was the donor in two and NIMA-mismatched siblings were donors in three cases. HLA disparity in both graft-versus-host (GVH) and host-versus-graft directions (HVG) included two loci mismatches in one patient, and three loci mismatches in five patients. Microchimerism was detected by HLA-nested polymerase chain reaction (PCR) with a single specific primer in the donor for all patients. The conditioning regimen consisted of fludarabine 25 mg/m 2 i.v. for 5 d (days ) 6t o)2) and melphalan 80 mg/m 2 i.v. on day )3. GVH disease (GVHD) prophylaxis consisted of tacrolimus 0AE02 mg/kg/d i.v., with methotrexate 5 mg/m 2 i.v. on days 1, 3,

Infectious complications in reduced intensity conditioning (RIC) allogeneic stem cell transplantation with antilymphocyte antibodies

6627 Background: Infection is a frequent cause of morbidity and mortality following allogeneic stem cell transplantation. It is still not clear whether RIC regimens have an impact on incidence and severity of infections. Methods: We analyzed infectious complications and outcome in 53 patients with median age of 55 years (range, 16–75 years) who underwent allogeneic stem cell transplantation with a RIC regimen consisting of Fludarabine, total body irradiation, antithymocyte globulin or Campath with or without CD45 monoclonal antibodies. Sixty eight percent (36/53) of patients received Campath based regimen. Donors were HLA identical (24 related and 17 unrelated) or one antigen mismatched (3 related, 9 unrelated). Infectious prophylaxis was Levofloxacin, fluconazole, Ganciclovir and Bactrim. Results: There were 122 episodes of fever or other clinical infections, 54 were before day +30, 46 between day +30 and day +100, and 22 after day +100. Bacteria were isolated in 42% (5 gram negative, 46 gram positive), fungi in 6% (1 invasive aspergillosis, 6 yeast) and viruses in 9% (3 adeno, 6 herpes simplex, 1 parainfluenza, 1 CMV). Cultures were negative in 43% of episodes. CMV reactivation occurred in 21% (11/53), only one had CMV disease. Non relapse mortality was 11% (6/53), severe infections 4 (staph aureus 1, pseudomonas 1, adenovirus 1, yeast and VRE 1), GVHD (1) and idiopathic pneumonia syndrome (1). Thirty two percent (17/53) of patients died of disease progression and 57% (30/53) are alive at a median follow up of 15 months. Only donor CMV +/recipient CMV+ status was significantly associated with CMV reactivation, (P= .01). Conditioning regimen with Campath, acute or chronic GVHD, treatment with steroids or tacrolimus or donor type did not influence the risk of CMV reactivation, bacterial, viral or fungal infections. Conclusions: RIC stem cell transplantation using antilymphocyte antibodies is associated with low incidence of life threatening infections and non-relapse mortality. No significant financial relationships to disclose.

57 Reduced-intensity conditioning stem cell transplant (RIC-SCT) with fludarabine/busulfan/ATG for hematopoietic malignancies

57 Reduced-intensity conditioning stem cell transplant (RIC-SCT) with fludarabine/busulfan/ATG for hematopoietic malignancies