Sinusoidal obstruction syndrome, also known as veno-occlusive disease (SOS/VOD), is a potentially life-threatening complication that can develop after hematopoietic cell transplantation (HCT). While SOS/VOD may resolve within a few weeks in the majority of patients with mild-to-moderate disease, the most severe forms result in multiorgan dysfunction and are associated with a high mortality rate (>80%). Therefore, careful surveillance may allow early detection of SOS/VOD, particularly as the licensed available drug is proven to be effective and reduce mortality. The aim of this work is to propose an international consensus guideline for the treatment and prevention of SOS/VOD in adult patients, on behalf of an international expert group.

Abstract Background Prophylactic systemic antibiotics (PSA) during conditioning regimen-induced neutropenia after hematopoietic cell transplantation (HCT) reduce bacteremia but may disrupt the gut microbiota, potentially affecting viral immunity and risk for viral infections. Prior studies suggest a critical role of gut microbiota in the reconstitution of CMV-specific CD8+ T cells and in protection from respiratory viral infections after HCT (J Immunol 2007; 178: 5209; Blood 2018; 131:2978). To identify whether PSA is associated with differences in CMV infection outcomes after HCT, we conducted a post-hoc analysis of CMV infection in the only RCT of PSA exclusively performed in HCT recipients (Infection 1986; 14:115). In that trial, HCT patients received either PSA (ticarcillin/tobramycin/vancomycin or mezlocillin/ceftizoxime) or no systemic antibiotics during neutropenia (absolute neutrophil count <500/mm3). Methods A post-hoc analysis was performed of a previously conducted RCT in the pre-antiviral era (1984–1986) at the Fred Hutch. Patients received unscreened blood products and were tested weekly by CMV culture in throat, and disease was evaluated by tissue biopsy or bronchoalveolar lavage. CMV disease was confirmed by chart review. We compared the cumulative incidence of CMV at any site, CMV throat shedding, and CMV disease between randomization groups by day 100 post-transplant, treating death as a competing risk. Overall survival was also compared using Kaplan–Meier method. Results 119 and 125 allograft recipients were randomized to PSA and no prophylaxis, respectively. Baseline characteristics in both groups were balanced. CMV infection at any site and CMV throat shedding were greater in the PSA group (Figures 1 and 2); CMV disease was numerically reduced in the no PSA group (Figure 3). Overall survival by day 100 was not different between the groups (Figure 4). Conclusion CMV infection risk appeared to be increased in recipients of PSA with a significant anaerobic spectrum. While current PSA regimens have narrower spectrum activity, these results provide the rationale to study if changes in gut microbiota play a role in CMV reactivation and adaptive immunity after HCT. Disclosures All authors: No reported disclosures.

A non-myeloablative regimen of fludarabine and 200 cGy total body irradiation combined with post-grafting immunosuppression with mycophenolate mofetil and a calcineurin inhibitor facilitates allogeneic hematopoietic cell transplantation from HLA-matched related or unrelated donors in older patients and/or those with comorbidities. However, outcomes of prior studies have been disappointing in patients with myelodysplastic syndromes or myeloproliferative neoplasms due to high incidences of progression or graft failure (together termed hematopoietic cell transplantation-failure). We hypothesized that escalating the total body irradiation dose may improve the outcomes and subsequently performed a phase II total body irradiation dose-escalation trial. Patients with median age 66 years were enrolled in two arms to receive non-myeloablative conditioning followed by hematopoietic cell transplantation with total body irradiation dose escalation for excessive hematopoietic cell transplantation-failure: Arm A: myeloproliferative neoplasm/myelodysplastic syndrome low risk (n=36); and Arm B: myelodysplastic syndrome high-risk/chronic myelomonocytic leukemia (n=41). Total body irradiation dose levels were: Level-1 (300 cGy), Level-2 (400 cGy), or Level-3 (450 cGy). Patients received intravenous fludarabine 30 mg/m2 for three days. Total body irradiation was administered on day 0 followed by infusion of peripheral blood stem cells from HLA-matched related (n=30) or unrelated (n=47) donors. Post-grafting immunosuppression with mycophenolate mofetil and cyclosporine was administered. The primary end point was day 200 hematopoietic cell transplant failure, with the objective of reducing the incidence to <20%. The primary end point was reached on Arm A at dose Level-1 (300 cGy total body irradiation) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 11%, and on Arm B at dose Level-3 (450 cGy) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 9%. Increasing the total body irradiation dose leads to a higher success rate with non-myeloablative conditioning by reducing relapse and rejection. Further studies are necessary to decrease non-relapse mortality, especially among patients with high-risk disease. Trial registered under clinicaltrials.gov identifier: NCT00397813.

Background: Nonmyeloablative conditioning with 2-Gy TBI alone or in combination with fludarabine (FLU/TBI) and HLA-matched related donor peripheral blood allografts followed by cyclosporine (CSP) and mycophenolate mofetil (MMF) for the prophylaxis of graft-versus-host disease (GVHD) is an effective therapy for many hematologic malignancies with reliable engraftment and moderate toxicity. The major causes of non-relapse mortality (NRM) are the development of acute and chronic GVHD. Several studies have demonstrated that tacrolimus may offer advantages compared with CSP for the prevention of GVHD in patients treated with myeloablative conditioning. The combination of tacrolimus and MMF, which has been used for GVHD prophylaxis after myeloablative hematopoietic cell transplantation (HCT), was well tolerated with low toxicity. Pilot data suggested an improved and perhaps superior GVHD prophylaxis with tacrolimus/MMF compared to our extensive historical experience using CSP/MMF with nonmyeloablative HCT. The purpose of this study is to evaluate the incidence of grade III-IV and II-IV acute GVHD, extensive chronic GVHD, along with the rate of NRM, relapse/progression, and overall survival after nonmyeloablative conditioning and post-grafting immunosuppression with tacrolimus and MMF.

The study is a randomized phase II trial investigating graft-versus-host disease prophylaxis after non-myeloablative (90 mg/m(2) fludarabine and 2 Gy total body irradiation) human leukocyte antigen matched unrelated donor transplantation. Patients were randomized as follows: arm 1 - tacrolimus 180 days and mycophenolate mofetil 95 days (n=69); arm 2 - tacrolimus 150 days and mycophenolate mofetil 180 days (n=71); arm 3 - tacrolimus 150 days, mycophenolate mofetil 180 days and sirolimus 80 days (n=68). All patients had sustained engraftment. Grade II-IV acute graft-versus-host disease rates in the 3 arms were 64%, 48% and 47% at Day 150, respectively (arm 3 vs. arm 1 (hazard ratio 0.62; P=0.04). Owing to the decreased incidence of acute graft-versus-host disease, systemic steroid use was lower at Day 150 in arm 3 (32% vs. 55% in arm 1 and 49% in arm 2; overall P=0.009 by hazard ratio analysis). The Day 150 incidence of cytomegalovirus reactivation was lower in arm 3 (arm 1, 54%; arm 2, 47%; arm 3, 22%; overall P=0.002 by hazard ratio analysis). Non-relapse mortality was comparable in the three arms at two years (arm 1, 26%; arm 2, 23%; arm 3, 18%). Toxicity rates and other outcome measures were similar between the three arms. The addition of sirolimus to tacrolimus and mycophenolate mofetil is safe and associated with lower incidence of acute graft-versus-host disease and cytomegalovirus reactivation.

The risks and benefits of adding fludarabine to a 2-Gy total body irradiation (TBI) nonmyeloablative regimen are unknown. For this reason, we conducted a prospective randomized trial comparing 2-Gy TBI alone, or in combination with 90 mg/m(2) fludarabine (FLU/TBI), before transplantation of peripheral blood stem cells from HLA-matched related donors. Eighty-five patients with hematological malignancies were randomized to be conditioned with TBI alone (n = 44) or FLU/TBI (n = 41). All patients had initial engraftment. Two graft rejections were observed, both in the TBI group. Infection rates, nonrelapse mortality, and graft-versus-host disease (GVHD) were similar between groups. Three-year overall survival was lower in the TBI group (54% versus 65%; hazard ratio [HR], .57; P = .09), with higher incidences of relapse/progression (55% versus 40%; HR, .55; P = .06), relapse-related mortality (37% versus 28%; HR, .53; P = .09), and a lower progression-free survival (36% versus 53%; HR, .56; P = .05). Median donor T cell chimerism levels were significantly lower in the TBI group at days 28 (61% versus 90%; P < .0001) and 84 (68% versus 92%; P < .0001), as was NK cell chimerism on day 28 (75% versus 96%; P = .0005). In conclusion, this randomized trial demonstrates the importance of fludarabine in augmenting the graft-versus-tumor effect by ensuring prompt and durable high-level donor engraftment early after transplantation.

Abstract Background While delayed or failed engraftment following reduced intensity conditioning (RIC) umbilical cord blood transplant (UCBT) now occurs less frequently than initially reported, it continues to be higher than in the conventional donor setting. It has been shown that patients who have had a prior autologous transplant or who have received chemotherapy within 4 months of UCBT have an increased incidence of sustained donor engraftment compared with those without this prior therapy (98% vs 64%) (Barker et al ASH abstract 2003). The standard measure of engraftment following UCBT is neutrophil recovery to > 500 x 3 days. However, there has recently been established a possible correlation between time to neutrophil engraftment and early full donor chimerism after UCBT (Avery S et al BMT 2012). Herein, we conducted an RIC UCBT trial in which patients were assigned to one of two treatment regimens based on their risk of graft failure. In addition to evaluating sustained donor engraftment characterized by time to neutrophil recovery, we also sought to assess the achievement of full donor chimerism at Day +28 post-transplant in patients pre-determined to be high versus low risk of graft failure. Methods Forty-eight patients median age 59 years (range 25 - 73) and comorbidity index = 3 (range 0 - 8) with high risk hematologic malignancies received an RIC regimen containing cyclophosphamide 50mg/kg on Day -6, fludarabine 40mg/m2 Day -6 to -2 (dose reduced to 35mg/m2 for creatinine clearance < 70), and either 200 cGy TBI (Arm 1 = low risk of graft failure) or 300 cGy TBI (Arm 2 = high risk of graft failure) on Day -1. High risk for graft failure was defined as “receiving < 2 cycles of multiagent chemotherapy or no multiagent chemotherapy within the 3 months prior to UCBT.” Low risk for graft failure was defined as “having received a prior autologous transplant within 12 months or ≥ 2 cycles of multiagent chemotherapy with at least one cycle of therapy within the 3 months prior to UCBT.” Patients on both arms received GVHD prophylaxis with cyclosporine from Day -1 to Day +180 and mycopheolate mofeteil 1 gram every 8 hours until Day +40. Forty-seven of 48 patients received 2 UCB units (one patient received a single UCB) with a median TNC/kg of 4.05 x 107 and a post-thaw median CD34+cells/kg of 1.75 x 105. UCB grafts (98%) were 1-2 HLA antigen mismatched with the recipient. Twenty-six patients were assigned to Arm 1 and 22 patients were assigned to Arm 2. Bone marrow and peripheral blood chimerism assessment were performed at approximately Day +28 and Day +80. The blood was flow sorted in the clinical hematopathology lab into defined lineage subsets. Wilcoxon rank-sum test was used to compare the 2 groups. Results All evaluable patients engrafted (n = 46). Patients on Arm 1 achieved neutrophil recovery (ANC > 500 x 3 days) at a median of 12 days (range 6 - 38) versus 23 days (range 7- 46) in patients on Arm 2 (p = 0.01). Day +28 chimerism values were evaluable for 23 patients on Arm 1 and 20 patients on Arm 2. Median chimerism in the CD3+ compartment was 100% (57 - 100) and 100% (0 - 100) on Arm 1 and Arm 2 respectively (p = 0.58). Median chimerism in the CD33+compartment was 98% (15 - 100) and 100% (44-100) on Arm 1 and Arm 2 respectively (p =0.26). Median chimerism in the bone marrow was 98% (15 - 100) and 100% (4 - 100) on Arm 1 and Arm 2 respectively (p = 0.84). This was maintained at Day +80. Acute graft versus host disease (GVHD) grades II - IV was seen in 84% (n = 21) and 68% (n = 15) of patients on Arm 1 and 2 respectively with 5% and 12% grade III-IV GVHD in the respective arms. Chronic GVHD was seen in 40% of patients on Arm 1 (8 mild, 2 moderate) and 23% on Arm 2 (3 mild, 1 moderate, 1 severe). Overall survival at 1 year in Arm 1 was 43% (95% CI: 22-62%) and Arm 2 was 46% (95% CI: 20-69%). Conclusions The goal of this RIC UCBT study was to assess engraftment rates by neutrophil recovery and Day +28 chimerism in patients at low versus high risk of graft rejection. Although time to neutrophil recovery was significantly faster in patients with low risk of graft failure, patients at high risk of rejection achieved a similar incidence of full donor chimerism at Day +28 as those with low risk of graft rejection. Using Day +28 chimerism as a measure of engraftment, patients deemed high risk of graft failure achieved early engraftment with UCBT following an RIC conditioning regimen containing 300cGy TBI. Disclosures: No relevant conflicts of interest to declare.

PURPOSEWe designed a minimal-intensity conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) in patients with advanced hematologic malignancies unable to tolerate high-intensity regimens because of age, serious comorbidities, or previous high-dose HCT. The regimen allows the purest assessment of graft-versus-tumor (GVT) effects apart from conditioning and graft-versus-host disease (GVHD) not augmented by regimen-related toxicities.PATIENTS AND METHODSPatients received low-dose total-body irradiation ± fludarabine before HCT from HLA-matched related (n = 611) or unrelated (n = 481) donors, followed by mycophenolate mofetil and a calcineurin inhibitor to aid engraftment and control GVHD. Median patient age was 56 years (range, 7 to 75 years). Forty-five percent of patients had comorbidity scores of ≥ 3. Median follow-up time was 5 years (range, 0.6 to 12.7 years).RESULTSDepending on disease risk, comorbidities, and GVHD, lasting remissions were seen in 45% to 75% of patients, and 5-year survival ranged from 25% to 60%. At 5 years, the nonrelapse mortality (NRM) rate was 24%, and the relapse mortality rate was 34.5%. Most NRM was a result of GVHD. The most significant factors associated with GVHD-associated NRM were serious comorbidities and grafts from unrelated donors. Most relapses occurred early while the immune system was compromised. GVT effects were comparable after unrelated and related grafts. Chronic GVHD, but not acute GVHD, further increased GVT effects. The potential benefit associated with chronic GVHD was outweighed by increased NRM.CONCLUSIONAllogeneic HCT relying on GVT effects is feasible and results in cures of an appreciable number of malignancies. Improved results could come from methods that control progression of malignancy early after HCT and effectively prevent GVHD.

Abstract 1943 Reduced intensity conditioning (RIC) regimens in umbilical cord blood transplant (UCBT) are increasingly utilized for older patients (pts) and those with comorbidities. However, the optimal conditioning regimen has not yet been established and remains a significant challenge of this therapeutic approach. Incorporation of ATG into the conditioning regimen is thought to decrease the incidence of graft rejection, but it is associated with high incidence of infusion associated reactions and serum sickness, delayed T cell recovery, increased infections and higher risk of EBV post-transplant lymphoproliferative disorder (PTLD). We report the results of a non-ATG containing RIC regimen, in which ATG is replaced with a higher dose of TBI in pts considered to be at higher risk of graft failure. All pts received fludarabine (40mg/m2/day) from day −6 to day −2 and cyclophosphamide (50mg/kg) on day −6. Pts who had received a previous autologous transplant within 12 months or ≥ 2 cycles of multiagent chemotherapy with at least one cycle of therapy within the 3 months previous to UCBT received a single fraction of 200cGy TBI on day −1. All other pts were considered at higher risk of graft rejection and received a single fraction of 300cGy of TBI on day −1. GVHD prophylaxis began on day −3 and consisted of cyclosporine A (CSA) and mycophenolate mofetyl (MMF). CSA was continued until at least day +100 and then tapered 10% per week starting on day +101 and discontinued no sooner than 6 months post-transplant. The duration of MMF was prolonged, with initiation of a taper on day+40 post transplant and then in the absence of GVHD, tapered by 12% per week and discontinued after day + 96. Thirty pts underwent double UCBT at 3 transplant centers using this protocol between February 2006 and January 2011. Median age and weight of the pts were 60 (range, 24–73) years and 78 (range, 55–141) kg, respectively. Disease status included AML-CR1 (n=11) and CR2 (n=5), ALL-CR2 (n=1) and refractory ALL (n=2), biphenotypic leukemia in 1 st CR (n=1), MDS (n=1), relapsed/ refractory Hodgkin lymphoma (n=3), transformed DLBCL (n=1), primary PTCL (n=1) and very high grade B cell lymphoblastic lymphoma in 2 nd CR (n=1). Nine pts (30%) had failed prior hematopoietic cell transplantation (HCT), of which 5 were auto, 3 were allo and 1 both auto and allo transplant. All pts received 2 cord blood units to achieve the required cryopreserved cell dose of 3.0×10 7 TNC/kg. The median cell doses infused were 4.92 × 10 7 (range, 3.12–8.3) TNC/kg and 0.26×10 6 (range, 0.02–2.85) CD34+ cells/kg. Among the 60 infused units, HLA matching was 6/6 in 3% (n=1), 5/6 in 30% (n=9) and 4/6 in 67% (n=20) of the pts. Twenty-two pts (73%) received 2GY and 8 (27%) received 3Gy of TBI. The median number of prior treatments and comorbidity score were 3 (range, 0–8) and 3 (range, 1–8), respectively. The median follow up was 183 days (range, 132 to 1303 days). Neutrophils engraftment occurred in all pts at a median of 13 (range, 6 to 40) days and platelet (PLT) engraftment (>50×10 9 /L ) occurred at a median of 32 (range, 23 to 42) days, respectively. There was only one case of secondary graft rejection and no cases of primary graft rejection. The cumulative incidence of acute GVHD grade II-IV and III-IV were 60% and 24%, respectively; the cumulative incidence of chronic GVHD was 18%. Day 100 NRM was 17%. At one year, NRM, OS and PFS were 29%, 53% and 45%, respectively. Causes of death included relapse (n=6), multi-organ failure (n=2), sepsis (n=1), diffuse alveolar hemorrhage (n=1), necrotizing hemorrhagic meningitis (n=1), leukoencephalopathy (n=1) and intracranial bleed (n=1). There were no cases of CMV disease or PTLD. On multivariate analysis, only neutrophil and platelet engraftment were associated with mortality, with hazard ratios of 0.07 (95%, CI 0.009–0.61), p=0.01) and 0.11 (95%, CI 0.03–0.41, p=0.0009), respectively. Other variables, such as age, number of previous regimens, presence of minimal residual disease prior to transplant, dose of TBI (3Gy vs 2Gy), high-risk disease, comorbidity score and acute GVHD grade II-IV were not statistically significantly associated with poorer survival. In summary, results of this study to date demonstrate that this non-ATG containing conditioning regimen, with intensified immunosuppression and increased dose of TBI, provides a low incidence of graft rejection without increasing toxicity or the incidence of chronic GVHD. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3450 Objective: Allogeneic hematopoietic cell transplantation (HCT) following a variety of reduced-intensity conditioning regimens has been reported to produce encouraging results in patients with AML. In these studies disease relapse was the main cause of treatment failure, with 2–4 year relapse rates ranging between 32–61% resulting in overall survivals of 28–45% at 2–4 years. Our goal here was to examine whether pre-HCT variables could identify patients at high risk for relapse following nonmyeloablative allogeneic HCT, who thus would become candidates for additional interventions to reduce the risk of AML relapse. Methods: The data were derived from 274 consecutive Seattle Consortium patients (median age: 60 years) with de novo or secondary AML who underwent allogeneic HCT from related or unrelated donors after conditioning with 2 Gy total body irradiation (TBI) with or without fludarabine (90 mg/m2) as recently reported (Gyurkocza et al., JCO 2010 Jun 10;28(17):2859–2867). Cox regression was used to perform multivariate analysis of risk factors for relapse in a subset of 231 patients in morphologic leukemia-free state (defined as less than 5% marrow blasts) with (n=134) or without (n=97) peripheral blood cell count recovery (defined as platelets > 100,000/ml and neutrophils > 1,000/ml) at the time of HCT. In this multivariate model, AML beyond 1st complete remission (CR1), unfavorable cytogenetics (according to SWOG criteria), incomplete peripheral blood cell count recovery before HCT, and shorter time between diagnosis and HCT were associated with statistically significantly higher risk of relapse (Table 1). From this multivariate model we developed a relapse risk score that summarizes the contribution of multiple risk factors by assigning weights based on the relative magnitude of the log hazard ratios associated with the principal risk factors. From a starting score of 0, points were added or subtracted based on the following factors: 2nd CR: +1 point; 3rd or later CR: +2 points; unfavorable cytogenetics: +1 point; absence of pre-HCT peripheral blood cell count recovery: +0.5 points; time from diagnosis to HCT > 18 months, -2 points (Table 2). Patients were then stratified into 2 relapse risk groups according to whether the total risk score was ≤0 (low-risk) or >0 (high-risk). Results: Stratification of patients according to the proposed Relapse Risk Score resulted in a clear separation of the two risk groups, with 5-year relapse rates of 50% and 17% in the high- and low-risk groups, respectively (Figure 1A). Five-year overall survival rates were 26% and 50% in the high- and low-risk groups, respectively (Figure 1B). Conclusion: Our Relapse Risk Score may be a useful tool to identify patients with AML at high risk for relapse, who could potentially benefit from additional interventions to reduce the risk of relapse following allogeneic HCT. We are currently attempting validation in an independent cohort of patients with AML to make this Risk Score more generalizable. Relapse/Progression (A) and Overall Survival (B) rates stratified by Relapse Risk Score. Disclosures: Off Label Use: Off label usage of fludarabine, cyclosporine, tacrolimus and mycophenolate mofetil is discussed.

A 24-year-old woman with advanced Hodgkin disease received the standard dosing protocol for busulfan/cyclophosphamide before allogeneic hematopoietic stem cell transplantation (HSCT)1 from a matched unrelated donor. The target area under the plasma concentration vs time curve (AUC) for busulfan was set at 950 μmol · L−1 · min−1, near the low end of the therapeutic interval of 900–1350 μmol · L−1 · min−1. The patient’s body mass index (BMI) was 45.5 kg/m2 (height, 170.2 cm; weight, 132.0 kg), so the dose was based on the patient’s ideal body weight. The patient received 2-hour intravenous infusions of busulfan every 6 h for 4 days (16 doses total). The patient was concurrently prescribed multiple medications, including an immunosuppressant, an antiviral, an antifungal, an antidepressant, an anxiolytic, a β-blocker, and a muscle relaxant, as well as antibiotics, warfarin, opioids, and antiepileptic drugs. After the first dose (51 mg Busulfex®; Otsuka Pharmaceutical), timed plasma samples were collected after infusion to determine the AUC. Pharmacokinetics (PK) analysis was performed, and the AUC was determined to be 642 μmol · L−1 · min−1. According to these results, the predicted busulfan dosage required to achieve the target AUC was 75 mg per dose for the remaining 14 scheduled doses. Because of the large change in dosage, additional PK monitoring of busulfan was performed after the fifth dose (day 2). The fifth dose was selected to allow time to reach a steady-state concentration (Css) after the dosage adjustment and to avoid challenges in interpretation due to possible circadian variation in busulfan concentrations (1). Samples for monitoring were collected at the same time of day as the first monitoring dose. The AUC after the fifth dose was 1342 μmol · L−1 · min−1. On the …

Purpose Allogeneic hematopoietic cell transplantation (HCT) after high-dose conditioning regimens imposes prohibitively high risks of morbidity and mortality for patients with high-risk acute myeloid leukemia (AML) who are older or have comorbid conditions. Here, we examined outcomes after nonmyeloablative allogeneic HCT in such patients. Patients and Methods Two hundred seventy-four patients (median age, 60 years) with de novo or secondary AML underwent allogeneic HCT from related (n = 118) or unrelated donors (n = 156) after conditioning with 2 Gy of total-body irradiation (TBI) with or without fludarabine. A calcineurin inhibitor and mycophenolate mofetil were used for postgrafting immunosuppression. Results With a median follow-up of 38 months in surviving patients, the estimated overall survival at 5 years was 33%. The estimated 5-year relapse/progression and nonrelapse mortality rates were 42% and 26%, respectively. The cumulative incidences of grades 2, 3, and 4 acute graft-versus-host disease (GVHD) were 38%, 9%, and 5%, respectively. The cumulative incidence of chronic GVHD at 5 years was 44%. Patients in first and second complete remission had better survival rates than patients with more advanced disease (37% and 34% v 18%, respectively). Patients with HLA-matched related or unrelated donors had similar survivals. Unfavorable cytogenetic risk status was associated with increased relapse and subsequent mortality. Chronic GVHD was associated with lower relapse risk. Conclusion Allogeneic HCT from related or unrelated donors after conditioning with low-dose TBI and fludarabine, relying almost exclusively on graft-versus-leukemia effects, can result in long-term remissions in older or medically infirm patients with AML.

HLA-mismatched grafts are a viable alternative source for patients without HLA-matched donors receiving ablative hematopoietic cell transplantation (HCT), although their use in reduced intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT has been not well established. Here, we extended HCT to recipients of HLA class I-mismatched grafts to investigate whether NMA conditioning can establish stable donor engraftment. Fifty-nine patients were conditioned with fludarabine (Flu) 90 mg/m(2) and 2 Gy total body irradiation (TBI), followed by immunosuppression with cyclosporine (CsA) 5.0 mg/kg twice a day and mycophenolate mofetil (MMF) 15 mg/kg 3 times a day for transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stern cells (PBSCs) from related (n = 5) or unrelated donors (n = 54) with I antigen +/- I allele HLA class I mismatch or 2 HLA class I allele mismatches. Sustained donor engraftment was observed in 95% of the evaluable patients. The incidence of grade II-IV acute and extensive chronic graft-versus-host disease (aGVHD, cGVHD) was 69% and 41%, respectively. The cumulative probability of nonrelapse mortality (NRM) was 47% at 2 years. Two-year overall and progression-free survival (OS, PFS) was 29% and 28%, respectively. NMA conditioning with Flu and low-dose TBI, followed by HCT using HLA class I-mismatched donors leads to successful engraftment and long-term survival; however, the high incidence of aGVHD and NRM needs to be addressed by alternate GVHD prophylaxis regimens. Biol Blood Marrow Transplant 16: 384-394 (2010) (C) 2010 American Society for Blood and Marrow Transplantation

Dose-intense conditioning (DIC) (myeloablative) regimens for allogeneic stem cell transplantation (alloSCT) were previously avoided in patients with acute myelogenous leukemia aged more than 55 years because of the fear of excessive morbidity and mortality. The introduction of reduced-intensity conditioning (RIC) alloSCT led to their increasing use in these patients because of their reduced toxicity. Significant disadvantages remain, however, including the late establishment of a posttransplant graft-versus-leukemia effect and an overrepresentation of poor prognostic factors in elderly patients, resulting in the risk of early relapse/progression before the graft-versus-leukemia effect being disproportionally large. Preliminary results suggest that DIC with maximum prophylaxis and support is safe for elderly patients up to age 70 years. We hypothesize that DIC may be important for the early control of leukemia in elderly patients, and that prospective, randomized trials comparing DIC and RIC-based transplants should be carried out, with the expectation that early transplant-related mortality will be no different.

Median ages of pts with most hematological malignancies are beyond 60 years. The advent of nonmyeloablative conditioning regimens has extended the use of allogeneic HCT to these older pts. Here, we retrospectively investigated outcomes among 280 pts aged ≥60 years, given HCT between 1998 and 2006. Results were broken down in 3 age groups 60–64 (n=166), 65–69 (n=90), and ≥70 (n=24) years old, respectively. Pts aged ≥70 years had less preceding chemotherapy, less often failed autologous HCT, more often had related grafts, and had higher comorbidity scores compared to pts in the other two age groups (table 1). Acute leukemias were more frequent and lymphoma/multiple myeloma were less frequent among pts aged ≥70 years old, resulting in higher risk for relapse (Table 1). After HCT, non-relapse mortality, relapse, and progression free survivals at 5-years for all pts were 26%, 41%, and 32% respectively. Five-year Kaplan Meier rate of overall survival was 35%, of those 12% vs. 23% were with vs. without chronic GVHD requiring immunosuppressive therapy, respectively. There were no statistically significant differences in outcomes among the three age groups except for more infections and days of hospitalization among pts aged 65–69 years compared to the other two age groups (Table 2). In multivariate analyses of risk factors, high HCT-comorbidity index (1–2 and ≥3) independently predicted higher NRM (HR: 2.84 and 3.0, respectively, p=0.01) and, not surprisingly, previously defined high relapse risk predicted relapse (HR: 2.17, p=0.06); both predicted worse OS (p=0.005 and p=0.0009, respectively) and PFS (p=0.01 and p=0.02, respectively). Pts given unrelated grafts did as well as recipients of related grafts. In conclusion, nonmyeloablative allogeneic HCT can be curative among pts older than 60 years with resolution of chronic GVHD among a majority of pts. Comorbidities and relapse risk rather than age should be used for benefit-risk assessment. Continued enrollment of elderly pts in prospective studies including unrelated donors is warranted.

Abstract We report the results of 256 patients (median age = 59; range, 5–74 years) with de novo AML in first complete remission (CR1; n=100), beyond CR1 (n=79) and with treatment-related or secondary AML (n=77) who underwent allogeneic hematopoietic cell transplantation (HCT) from HLA-matched related (n=109) or from unrelated donors (n=147). Indications of allogeneic HCT in CR1 were persistent cytogenetic or molecular evidence of disease, poor-risk cytogenetics at diagnosis, treatment-related or secondary AML and age more than 60 years. Younger patients were included if they had comorbid conditions that excluded them from conventional allogeneic HCT. Sixteen patients were mismatched with their donors for ≥ one HLA antigen, while the remainder were matched 10/10 at the antigen level. Conditioning consisted of low-dose total body irradiation (TBI; 2 Gy) on day 0 either alone (n=28) or combined with fludarabine, 30 mg/m2/day on days −4 to −2 (n=228). Calcineurin inhibitors (cyclosporine or tacrolimus) and mycophenolate mofetil were used for postgrafting immunosuppression. Durable engraftment was observed in 94% of patients. With a median follow-up of 35 (range, 3 – 111) months in surviving patients, the estimated progression-free and overall survivals at 5 years were 32% (95% CI: 25–38%) and 32% (95% CI: 25–38%), respectively. The cumulative incidences of relapse/progression and non-relapse mortality at 5 years were 40% (95% CI: 33–46%) and 29% (95% CI: 22–35%), respectively. Estimated 5-year survival rates, progression-free survival, relapse/progression rate, and non-relapse mortality according to disease status are shown in Table 1; Table 2 shows the same indices according to donor type. The cumulative incidences of grades II–IV and III–IV acute graft-versus-host disease (GVHD) in patients with related donors were 40% and 13%, and in those with unrelated donors were 58% and 14%, respectively. The cumulative incidence of chronic extensive GVHD at 5 years was 44% in patients with related donors, and 42% in patients with unrelated donors. Age > 60 years at the time of HCT did not have an impact on the outcome (univariate analysis). Additional analyses regarding the impact of HCT comorbidity scores and minimal residual disease at the time of HCT are in progress. Based on this multicenter analysis, we conclude that allogeneic HCT from related or unrelated donors, utilizing a conditioning regimen of low dose TBI (2 Gy) with fludarabine provides long term remission in elderly and/or medically infirm patients with AML, who were not considered candidates for conventional HCT. Table 1. Estimated 5-year overall survival (OS), progression-free survival (PFS), relapse/progression rate (RR), and non-relapse mortality (NRM) according to disease status. CR1: 1st remission; >CR1: subsequent remission, induction failure/persistent disease; sAML: treatment-related and secondary AML. Disease Status n %OS (95% CI) %PFS (95% CI) RR (95% CI) NRM (95% CI) CR1 100 33 (20–46) 34 (23–46) 36 (26–47) 30 (19–40) >CR1 79 38 (26–49) 35 (23–46) 40 (29–52) 25 (15–35) sAML 77 20 (8–32) 23 (11–35) 45 (32–57) 32 (20–45) Table 2. Estimated 5-year overall survival (OS), progression-free survival (PFS), relapse/progression rate (RR), and non-relapse mortality (NRM) according to donor type. Donor Type n %OS (95% CI) %PFS (95% CI) RR (95% CI) NRM (95% CI) HLA-identical related 109 34 (23–44) 34 (24–45) 47 (37–58) 18 (10–26) HLA-matched unrelated 131 31 (22–40) 30 (21–39) 37 (29–46) 33 (24–72) HLA mismatched unrelated 16 24 (0–50) 24 (0–50) 6 (0–18) 70 (43–97)

The anti-cytomegalovirus (CMV) activity and safety of oral maribavir in CMV-seropositive allogeneic stem-cell transplant recipients were evaluated in a randomized, double-blind, placebo-controlled, dose-ranging study. After engraftment, 111 patients were randomized to receive CMV prophylaxis with maribavir (100 mg twice daily, 400 mg once daily, or 400 mg twice daily) or placebo. Within the first 100 days after transplantation, the incidence of CMV infection based on CMV pp65 antigenemia was lower in each of the respective maribavir groups (15%, P = .046; 19%, P = .116; 15%, P = .053) compared with placebo (39%). Similarly, the incidence of CMV infection based on plasma CMV DNA was lower in each of the respective maribavir groups (7%, P = .001; 11%, P = .007; 19%, P = .038) compared with placebo (46%). Anti-CMV therapy was also used less often in patients receiving each respective dose of maribavir (15%, P = .001; 30%, P = .051; 15%, P = .002) compared with placebo (57%). There were 3 cases of CMV disease in placebo patients but none in the maribavir patients. Adverse events, mostly taste disturbance, nausea, and vomiting, were more frequent with maribavir. Maribavir had no adverse effect on neutrophil or platelet counts. These results show that maribavir can reduce the incidence of CMV infection and, unlike ganciclovir, does not cause myelosuppression.

Allogeneic hematopoietic cell transplantation (HCT) is the only curative strategy for patients with myelodysplastic syndrome (MDS) and myeloproliferative disorders (MPD). We report the results of 148 patients (median age = 59 years old) with de novo MDS (n = 40), acute myelogenous leukemia (AML) after antecedent MDS/MPD (n = 49), treatment-related MDS (t-MDS) (n = 25), MPD (n = 27), and chronic myelomonocytic leukemia (CMML) (n = 7) who underwent allogeneic HCT using a conditioning regimen of low-dose total body irradiation (TBI) alone (200 cGy) on day 0 (n = 5) or with the addition of fludarabine (Flu) 30 mg/m(2)/day on days -4 to -2 (n = 143). Postgrafting immunosuppression consisted of cyclosporine and mycophenolate mofetil (MMF). Seventy-five patients (51%) received an allograft from a matched related donor (MRD), and 73 patients (49%) were recipients of unrelated donor (URD) grafts. There was no significant difference in the incidence of acute (gr II-IV) and chronic extensive graft-versus-host disease (aGVHD, cGVHD) between the recipients of related and unrelated donor grafts. By day +28, 75% of patients demonstrated mixed T cell chimerism. Graft rejection was seen in 15% of patients. With a median follow-up of 47 (range: 6-89) months, the 3-year relapse-free survival (RFS) and overall survival (OS) are both 27% for all patients, with a relapse incidence of 41%. The 3-year RFS for the patients with de novo MDS, AML after antecedent MDS/MPD, t-MDS, MPD, and CMML were 22%, 20%, 29%, 37%, and 43%, respectively, and the 3-year OS was 20%, 23%, 27%, 43%, and 43%, respectively. The 3-year nonrelapse mortality (NRM) was 32%. Factors associated with a lower risk of relapse were the development of extensive cGVHD and having a low risk or intermediate-1 risk International Prognostic Score for the de novo MDS patients. Nonmyeloablative HCT confers remissions in patients who otherwise were not eligible for conventional HCT but for whom relapse is the leading cause of treatment failure.

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

Use of HLA-mismatched unrelated donors after myeloablative conditioning is an effective treatment of blood disorders when HLA-matched donors are not available. However, the feasibility of HLA-mismatched HCT following nonmyeloablative conditioning is not well established. We previously demonstrated in over 1200 patients (pts) that a nonmyeloablative conditioning regimen consisting of 2 Gy TBI and fludarabine (90 mg/m2) followed by post-grafting immunosuppression with MMF/CSP was an effective approach for HCT from 10/10 HLA-matched donors. Here we report the results of a clinical trial aimed at determining whether stable hematopoietic grafts from HLA-class I mismatched donors could be safely established after nonmyeloablative conditioning. Pts were conditioned with fludarabine and 2 Gy TBI, followed by extended immunosuppression with CSP (day −3 to +180; tapered by +365) and MMF (tid days 0 to +100; tapered by +150). 46 pts ineligible for myeloablative conditioning were enrolled on this multi-institutional study through April/07. 36 unrelated and 3 related donor-recipient pairs were mismatched in both the HVG and GVH vectors. 43 unrelated pairs were mismatched for at least one antigen (AG) (15 at HLA-A, 5 at HLA-B, 22 at HLA-C) except one pt who had two allele mismatches (HLA-A and B). All 3 related pairs were mismatched for one HLA-A AG. 13 pts, in addition to the AG mismatch, had an allelic mismatch (3 at HLA-A, 4 at HLA-B, 6 at HLA-C). All pts were matched for HLA-DRB1 and HLA-DQB1 at the allele level. Diagnoses included NHL (n=17), HD (n=5), AML (n=11), ALL (n=5), CLL (n=3), MM (n=4) and MDS/AML (n=1). The median age of pts was 56 (range 13–69) years and median time from diagnosis to HCT was 32 (range 5–205) months. Disease status at time of HCT included CR (n=23), PR (n=11), stable disease (n=2), and refractory relapse (n=10). Before HCT, pts had received a median of 7 (range 2–15) courses of therapy. 43% had failed myeloablative HCT (autologous n=18; allogeneic n=2). All pts received G-CSF mobilized PBSC containing median doses of 7.3 ×106 CD34 and 2.4 × 108 CD3 cells /kg. 12 pts were not evaluable for the graft rejection outcome (3 early death, 7 mismatched in GVH vector only, 2 tandem auto-allo). The remaining pts showed median percentages of donor peripheral blood T cell, granulocyte and marrow chimerism of 100% at all time points (on days 28, 56, and 84). Two pts experienced graft rejection but had a successful 2nd HCT from the same or an alternative donor. 35 of the 46 pts developed acute GVHD (2 grade I, 21 grade II, 5 grade III, 7 grade IV) and 15 developed chronic GVHD. At 2 years, the cumulative probabilities of relapse/progression and non-relapse mortality were 30% and 45%, respectively. The 2 year Kaplan-Meier estimates of OS and PFS were 27% and 25%. This study demonstrates that nonmyeloablative conditioning using fludarabine and low-dose TBI can be successfully used for grafts from pts with HLA- class I mismatched donors.