Impact of molecular residual disease post allografting in myelofibrosis patients

We screened 136 patients with myelofibrosis and a median age of 58 years who underwent allogeneic stem cell transplantation (AHSCT) for molecular residual disease for JAKV617F (n=101), thrombopoietin receptor gene (MPL) (n=4) or calreticulin (CALR) (n=31) mutation in peripheral blood on day +100 and +180 after AHSCT. After a median follow-up of 78 months, the 5-year estimated overall survival was 60% (95% confidence interval (CI): 50-70%) and the cumulative incidence of relapse at 5 years was 26% (95% CI: 18-34%) for the entire study population. The percentage of molecular clearance on day 100 was higher in CALR-mutated patients (92%) in comparison with MPL- (75%) and JAKV617F-mutated patients (67%). Patients with detectable mutation at day +100 or at day +180 had a significant higher risk of clinical relapse at 5 years than molecular-negative patients (62% vs 10%, P<0.001) and 70% vs 10%, P<0.001, respectively) irrespectively of the underlying mutation. In a multivariate analysis, high-risk diseases status (hazard ratio (HR) 2.5; 95% CI: 1.18-5.25, P=0.016) and detectable MRD at day 180 (HR 8.36, 95% CI: 2.76-25.30, P<0.001) were significant factors for a higher risk of relapse.

Ruxolitinib in corticosteroid-refractory graft-versus-host disease after allogeneic stem cell transplantation: a multicenter survey

Despite major improvements in allogeneic hematopoietic cell transplantation over the past decades, corticosteroid-refractory (SR) acute (a) and chronic (c) graft-versus-host disease (GVHD) cause high mortality. Preclinical evidence indicates the potent anti-inflammatory properties of the JAK1/2 inhibitor ruxolitinib. In this retrospective survey, 19 stem cell transplant centers in Europe and the United States reported outcome data from 95 patients who had received ruxolitinib as salvage therapy for SR-GVHD. Patients were classified as having SR-aGVHD (n=54, all grades III or IV) or SR-cGVHD (n=41, all moderate or severe). The median number of previous GVHD-therapies was 3 for both SR-aGVHD (1-7) and SR-cGVHD (1-10). The overall response rate was 81.5% (44/54) in SR-aGVHD including 25 complete responses (46.3%), while for SR-cGVHD the ORR was 85.4% (35/41). Of those patients responding to ruxolitinib, the rate of GVHD-relapse was 6.8% (3/44) and 5.7% (2/35) for SR-aGVHD and SR-cGVHD, respectively. The 6-month-survival was 79% (67.3-90.7%, 95% confidence interval (CI)) and 97.4% (92.3-100%, 95% CI) for SR-aGVHD and SR-cGVHD, respectively. Cytopenia and cytomegalovirus-reactivation were observed during ruxolitinib treatment in both SR-aGVHD (30/54, 55.6% and 18/54, 33.3%) and SR-cGVHD (7/41, 17.1% and 6/41, 14.6%) patients. Ruxolitinib may constitute a promising new treatment option for SR-aGVHD and SR-cGVHD that should be validated in a prospective trial.

Donor choice according to age for allo-SCT for AML in complete remission

In a retrospective study of 168 patients with AML in CR who underwent allo-SCT, we compare the impact of young unrelated donors (UD) vs older matched related donors (MRD) on 5-year OS (5-yr OS). Median follow-up was 59 months and median donor age was 39 years, which was used as cutoff for young vs older donors. Kaplan-Meier-estimated 5-yr OS was better with UD ≤39 years vs MRD >39 years (66% vs 34%, P=0.001). In multivariate analysis, only donor age and cytogenetic risk impacted 5-yr OS. Compared with UD ≤39 years, both MRD >39 years (relative risk (RR): 4.31, P=0.001) and UD >39 years (RR: 2.14, P=0.03) were associated with poorer 5-yr OS. Standard-risk cytogenetics was associated with better 5-yr OS compared with bad-risk cytogenetics, (RR: 0.53, P=0.02). Subgroup analyses of patients ≥50 years (n=76) revealed similar results, with 5-yr OS of 62% for UD ≤39 yrs and 26% for MRD >39 yrs (P=0.022). In patients undergoing allo-HSCT for AML, young UD may improve outcome as compared with older MRD.

EBV reactivation and post transplant lymphoproliferative disorders following allogeneic SCT

Fatal problems encountered in allogeneic stem cell transplantation include EBV reactivation and post transplant lymphoproliferative disorders (PTLDs) with high mortality rates. We performed a retrospective analysis in all consecutive adult and pediatric EBV reactivations and PTLD during a period of 8.5 years. There were 26 patients with EBV reactivation/PTLD out of a total of 854 transplantations giving an overall incidence of 3.0%. Specifically, the incidence of EBV-PTLD was 1.3%, whereas that of EBV reactivation was 1.8%. Median age was 46.0 and 11.0 years in the adult and pediatric patients, respectively. There were high rates (54%) of concomitant bacterial, viral, fungal and parasitic infections at the time of EBV manifestation. Variable treatment regimens were applied including in most cases an anti-CD20 regimen often in combination with virustatic compounds, polychemotherapy or donor lymphocytes. The mortality rates were 9 of 11 (82%) in patients with EBV-PTLD and 10 of 15 (67%) in patients with reactivation. Only 7 of 26 patients (27%) are alive after a median follow-up of 758 days (range 24-2751). The high mortality rates of EBV reactivation and of EBV-PTLD irrespective of multimodal treatment approaches emphasize standardization and optimization of post transplant surveillance and treatment strategies to improve control of these often fatal complications.

Impact of genetic abnormalities on survival after allogeneic hematopoietic stem cell transplantation in multiple myeloma

We analyzed the prognostic impact of the most frequent genetic abnormalities detected by fluorescence in situ hybridization in 101 patients with multiple myeloma, who underwent allogeneic hematopoietic stem cell transplantation (HSCT) after melphalan/fludarabine-based reduced conditioning. The incidences of abnormalities in the present analysis were as follows: del(13q14) (61%), t(11;14)(q13;q32) (14%), t(4;14)(p16.3;q32) (19%), MYC-gain gains (8q24) (21%), del(17p13) (16%) and t(14;16)(q32;q23) (5%). None of the patients had t(6;14)(p25;q32). The overall complete remission (CR) rate was 50% with no differences between the genetic abnormalities except for patients with del(17p13) who achieved less CR (7 vs 56%; P=0.001). Univariate analysis revealed a higher relapse rate in patients aged >50 years (P=0.002), patients with del(13q14) (P=0.006) and patients with del(17p13) (P=0.003). In multivariate analyses, only del(13q14) (HR: 2.34, P=0.03) and del(17p13) (HR: 2.24; P=0.04) significantly influenced the incidence of relapse, whereas for event-free survival, only age (HR 2.8; P=0.01) and del(17p13) (HR: 2.05; P=0.03) retained their negative prognostic value. These data show that del(17p13) is a negative prognostic factor for achieving CR as well as for event-free survival after HSCT. Translocation t(4;14) might be overcome by allogeneic HSCT, which will have implication for risk-adapted strategies.

Reduced-toxicity conditioning with treosulfan, fludarabine and ATG as preparative regimen for allogeneic stem cell transplantation (alloSCT) in elderly patients with secondary acute myeloid leukemia (sAML) or myelodysplastic syndrome (MDS)

We investigated a dose-reduced conditioning regimen consisting of treosulfan and fludarabine followed by allogeneic stem cell transplantation (SCT) in 26 patients with secondary AML or MDS. Twenty patients were transplanted from matched or mismatched unrelated donors and six from HLA-identical sibling donors. The median age of the patients was 60 years (range, 44-70). None of the patients was eligible for a standard myeloablative preparative regimen. No graft-failure was observed, and leukocyte and platelet engraftment were observed after a median of 16 and 17 days, respectively. Acute graft-versus-host disease (GvHD) grade II-IV was seen in 23% and severe grade III GvHD in 12% of the patients. No patients experienced grade IV acute GvHD. Chronic GvHD was noted in 36% of the patients, which was extensive disease in 18%. The 2-year cumulative incidence of relapse was 21%. The relapse rate was higher in patients beyond CR1 or with intermediate two or high risk MDS (P = 0.02). The treatment-related mortality at day 100 was 28%. The 2-year estimated overall and disease-free survival was 36-34%, respectively. No difference in survival was seen between unrelated and related SCT.

CD34+-selected stem cell boost for delayed or insufficient engraftment after allogeneic stem cell transplantation

BACKGROUND

Poor graft function without rejection may occur after stem cell transplantation (SCT). CD34(+) stem cell boost (SCB) can restore marrow function but may induce or exacerbate GvHD. We therefore investigated the feasibility and efficacy of CD34(+)-selected SCB in some patients with poor graft function. We present the results for eight patients (median age 46 years) transplanted initially for myelofibrosis, acute leukemia, myeloma and NHL. Six patients had received HLA-matched and two mismatched grafts (PB, BM; n=5, 3). After a median of 128 days post-transplant, the median leukocyte and platelet counts were, respectively, 2.05/nL and 18/nL. None had achieved platelet counts >50/nL even though donor chimerism was >95% in seven recipients.

METHODS

Positive selection of CD34(+) stem cells was performed on a CliniMACS device, observing GMP and achieving a median of 98.5% purity. The patients received a median of 1.7 x 10(6)/kg CD34(+) cells and 2.5 x 10(3)/kg CD3(+) T lymphocytes.

RESULTS

Hemograms at days +30, +60 and +90, respectively, showed steadily increasing median leukocyte (2.55, 3.15 and 4.20/nL) and platelet (29, 39 and 95/nL) counts. After a median follow-up of 144 days, five patients remained alive. No patient had developed acute or chronic GvHD. One patient died of leukemic relapse and two others of systemic mycosis.

DISCUSSION

These preliminary results point to the possibility of safely improving graft function using CD34(+) positively selected stem cells without necessarily increasing the incidence of GvHD in patients with poor graft function post-SCT. Experience with more patients and longer follow-up should clarify the optimal role for this procedure.

Comparable results in patients with acute lymphoblastic leukemia after related and unrelated stem cell transplantation

We report the results of 84 patients with ALL after related (n = 46) or unrelated (n = 38) allogeneic SCT. Mean recipient age was 23 years (range: 1-60) and median follow-up was 18 months (range: 1-133). Forty-three patients were transplanted in CR1; 25 in CR2 or CR3; four were primary refractory; four in PR; eight in relapse. The conditioning regimen consisted of TBI/VP16/CY (n = 76), TBI/VP16 (n = 2), TBI/CY (n = 2), Bu/VP16/CY (n = 4). The OS at 3 years was 45% (44% unrelated, 46% related). Univariate analysis showed a significantly better OS for patients <18 years (P=0.03), mismatched sex-combination (P = 0.03), both with a stronger effect on increasing OS after unrelated SCT. Factors decreasing TRM were patient age <18 years (P = 0.004), patient CMV-seronegativity (P = 0.014), female recipient (P = 0.04). There was no significant difference in TRM and the relapse rate was similar in both donor type groups. Multivariate analysis showed that factors for increased OS which remained significant were mismatched sex-combination (RR: 0.70,95% CI: 0.51-0.93, P = 0.015), patient age < 18 years (RR: 0.66, 95% CI: 0.47-0.93, P = 0.016). A decreased TRM was found for female patients (RR: 0.56, 95% CI: 0.33-0.98, P=0.042), negative CMV status of the patient (RR: 0.57, 95% CI: 0.36-0.90, P = 0.015). Unrelated stem cell transplantation for high-risk ALL patients with no HLA-compatible family donor is justifiable.

Allogeneic stem-cell transplantation in patients with refractory acute leukemia: a long-term follow-up

We examined retrospectively 44 patients with refractory acute leukemia (acute myeloid leukemia (AML)/acute lymphoblastic leukemia=25/19) who underwent allogeneic transplantation at our center between 11/1990 and 04/2004. The median leukemic blasts was 25% and age 28 years (range, 3-56). Twenty-one patients had untreated relapse, 13 failed reinduction, eight in partial remission and two aplastic. Conditioning was myeloablative using cyclophosphamide, busulfan, total-body irradiation and etoposide (Bu/Cy/VP, n=22; TBI/Cy/VP, n=17; others, n=5) followed by marrow or peripheral blood transplant (n=23/21) from unrelated or related donors (n=28/16). All patients had graft-versus-host disease (GVHD) prophylaxis with cyclosporin and methotrexate. One patient experienced late graft failure. Severe acute-GVHD and chronic-GVHD appeared in eight and 14 patients, respectively. Thirteen patients (30%) remain alive after a median of 25.3 months (range, 2.4-134.1); with 31 deaths, mostly from relapse (n=15) and infections (n=12). Overall survival (OS) and progression-free survival (PFS) at 5 years was 28 and 26%, respectively. OS and PFS were significantly better with blasts < or =20% and time to transplant < or =1 year while transplant-related mortality was less with the use of TBI. We conclude that patients with refractory leukemia can benefit from allogeneic BMT, especially with < or =20% marrow blast.

Hematopoietic stem-cell transplantation from unrelated donors in elderly patients (age>55 years) with hematologic malignancies: older age is no longer a contraindication when using reduced intensity conditioning

Allogeneic stem cell transplantation (SCT) is a potentially curative approach for patients with hematological malignancies. Reduced-intensity conditioning regimens allow SCT in elderly patients; however, there are only limited data on the feasibility and outcomes of unrelated donor SCT in these patients. In this study, we analyzed, retrospectively, data of 36 patients with various hematological malignancies and median age 58 years (range, 55-66), who were given unrelated donor SCT after reduced-intensity conditioning. The preparative regimen consisted of fludarabine combined with oral busulfan (8 mg/kg, n=8), intravenous busulfan (6.4 mg/kg, n=11), treosulfan (30 g/m(2), n=5) or melphalan (100-150 mg/m(2), n=12). Patients were also given serotherapy, ATG (n=32), or alemtuzumab (n=4). The probabilities of overall survival, disease-free survival, and nonrelapse mortality at 1 year after SCT were 52, 43, and 39%, respectively. Acute graft-versus-host disease (GVHD) grade II-IV and chronic GVHD occurred in 31 and 45%, respectively. Multivariable analysis determined that survival rates were higher in patients with chemosensitive disease (HR 4.5), and patients conditioned with intravenous busulfan or treosulfan (HR 3.9). Unrelated donor SCT is feasible in elderly patients, with outcomes that are similar to younger patients. Favorable outcome was observed in patients with myeloid malignancies, and those transplanted in remission and early in the course of disease. Age alone should not be considered a contraindication to unrelated donor SCT.

Long-term follow-up of allogeneic stem cell transplantation in patients with severe aplastic anemia after conditioning with cyclophosphamide plus antithymocyte globulin

We investigated the efficacy of an antithymocyte globulin/cyclophosphamide preparative regimen prior to allogeneic stem cell transplantation from HLA-identical siblings in patients with severe aplastic anemia. Since 1990, 21 patients, 6 males and 15 females, with a median age of 25 years (range: 7-43) have been enrolled in the protocol consisting of 200 mg/kg cyclophosphamide and 90-120 mg/kg antithymocyte globulin (ATG, rabbit, Fresenius, Bad Homburg, Germany). For further graft-versus-host disease (GVHD) prophylaxis all patients received cyclosporin A and a short course of methotrexate (MTX). Only one patient had a primary graft failure (5%). All other patients engrafted with a leukocyte count >1.0 x 10(9)/l and a platelet count >20 x 10(9)/l after a median of 19 (range: 11-28) and 26 days (range: 13-67), respectively. No late graft failure or relapse was observed. Two patients experienced mild acute GVHD grade I (10%), and one patient developed grade II GVHD (5%). No severe grade III/IV GVHD was observed; 17% of the patients developed limited chronic GVHD. The treatment-related mortality was 14% and mainly due to fungal infection. After a median follow-up of 70 months (range: 2-139), the estimated overall and event-free survival at 10 years for all patients is 86% (95% confidence interval: 70-100%). We conclude that ATG plus cyclophosphamide is an effective conditioning regimen in patients with aplastic anemia undergoing stem cell transplantation with a low treatment-related mortality, resulting in an excellent outcome.

In vivo T cell depletion with pretransplant anti-thymocyte globulin reduces graft-versus-host disease without increasing relapse in good risk myeloid leukemia patients after stem cell transplantation from matched related donors

One-hundred and two patients with good risk myeloid leukemia (CML first chronic phase or AML first CR) were transplanted from HLA-related donors after conditioning with (n = 45) or without anti-thymocyte globulin (ATG) (n = 57). One graft failure was observed in the non-ATG and none in the ATG group. The median time to leukocyte engraftment (> 1 x 10(9)/l) was 16 (range 12-33) in the ATG group and 17 days (range 11-29) in the non-ATG group (NS) and for platelet engraftment (> 20 x 10(9)/l) 24 and 19 days (P = 0.002), respectively. Acute GVHD grade II-IV was observed in 47% of the non-ATG and in 20% of the ATG group (P = 0.004). Grade III/IV GVHD occurred in 7% of the ATG and in 32% of the non-ATG group (P = 0.002). Chronic GVHD was seen in 36% and 67% (P = 0.005), respectively. After a median follow-up of 48 months (range 2-128), the 5-year estimated OS is 66% (95% KI: 51-81%) for the ATG group and 59% (95% KI: 46-72%) for the non-ATG group (NS). The 5-year estimated DFS is 64% (95% KI: 50-78%) for ATG and 55% (95% KI: 43-67%) for the non-ATG regimen (NS). The 5-year probability of relapse was 5% in the ATG and 15% in the non-ATG group (NS). ATG as part of the conditioning regimen leads to a significant reduction in GVHD without increase of relapse in patients with myeloid leukemia after stem cell transplantation from HLA-related donors.

Establishment of an optimised gene transfer protocol for human primary T lymphocytes according to clinical requirements

Current gene therapeutic protocols directed towards the treatment of inherited disorders (eg ADA-SCID) and viral infections (eg AIDS), as well as adoptive immunotherapy approaches are based on the use of genetically modified lymphocytes. Since only insufficient transduction of T cells is obtained using existing techniques, the development of more efficient gene transfer protocols into these cells is of great importance. We present here a protocol for the highly efficient transduction of human primary T cells at high densities (1 x 106/ml) by retroviral infection. Using retroviral vectors encoding a truncated human low-affinity nerve growth factor receptor (DeltaLNGFR) as a gene transfer marker, we obtained transduction frequencies of more than 70% of CD3+ cells after two cycles of infection. Our protocol is based on the use of FBS-free media for both the production of retrovirus-containing supernatant and the cultivation of the primary T cells. Since the protocol presented here works just as efficiently under large-scale conditions, it may be easily adapted to clinical needs and 'good manufacturing practice' (GMP) standards.