ALBERT

Description: GVHD is still one of the major complications after allogeneic stem cell transplantation. Whereas murine data have clearly shown the beneficial effects of regulatory T cells (Tregs) on the prevention of GVHD, data from the human system are rare. Here, we present a comparative dynamic analysis of CD4+CD25hiCD127lo/− Tregs from patients with and without GVHD analyzing the whole genome profile over the first 6 months after stem cell transplantation, representing the most sensitive time window for tolerance induction. The Treg transcriptome showed a high stability. However, the comparison of Treg transcriptomes from patients with and without GVHD uncovered regulated gene transcripts highly relevant for Treg cell function. The confirmative protein analyses demonstrated a significantly higher expression of granzyme A, CXCR3, and CCR5 in Tregs of immune tolerant patients. These results point to a reduced suppressive function of Tregs from GVHD patients with diminished migration capacity to the target organs.

Description: Abstract 3748 Graft-versus-host disease (GvHD) remains the major clinical complication in hematopoietic stem cell transplantation (SCT) resulting in severe morbidity and significant mortality. This alloreactive immune response is mainly induced by donor T cells transplanted with the graft. Regulatory T cells (Tregs) play an essential role in the induction and maintenance of peripheral tolerance. In addition, data from murine models have shown that Tregs can prevent GvHD while preserving the graft-versus-leukemia effect. In order to functionally and dynamically characterize human Tregs after allogeneic SCT, we analyzed CD4+CD25highCD127dim T cells isolated from the peripheral blood of more than 80 patients with hematological malignancies every 30 days over half a year following SCT. Patients were divided into the following clinical groups: (A) no signs of acute or chronic GvHD, (B) acute GvHD, (C) chronic GvHD and (D) acute GvHD passed into chronic GvHD. Human peripheral blood lymphocytes were separated by Ficoll gradient and CD4+CD14−CD25highCD127dim T cells were isolated by MoFlow cell sorting. Isolated RNA was pooled and microarray analysis was performed by using Affymetrix HG_U133_Plus2.0 Arrays. Results were verified by using quantitative realtime RT-PCR. Additionally, Tregs were phenotypically analyzed by FACS. We monitored a continous but slower recovery of Tregs in GvHD within the first 6 months following PBSCT. Manifestation of acute and chronic GvHD correlated with significantly reduced frequencies of peripheral Tregs in the first month after PBSCT compared to patients without GvHD. Microarray data revealed a high stability of the Treg transcriptome in the first half year representing the most sensitive time window for tolerance induction. Moreover, comparison of the Treg gene expression profiles from patients with and without GvHD point to a reduced suppressive function of Tregs with diminished migration capacity to the target organs likely contributing to the development of GvHD. Our findings corroborate the impact of human Tregs in the pathophysiology of GvHD and identify novel targets for the manipulation of Tregs to optimize strategies for prophylaxis and treatment of life-threatening GvHD. Disclosures: No relevant conflicts of interest to declare.

Description: Rabbit antithymocyte globulin (rATG; thymoglobulin, Genzyme) in combination with cyclosporine, as first-line immunosuppressive therapy, was evaluated prospectively in a multicenter, European, phase 2 pilot study, in 35 patients with aplastic anemia. Results were compared with 105 age- and disease severity–matched patients from the European Blood and Marrow Transplant registry, treated with horse ATG (hATG; lymphoglobulin) and cyclosporine. The primary end point was response at 6 months. At 3 months, no patients had achieved a complete response to rATG. Partial response occurred in 11 (34%). At 6 months, complete response rate was 3% and partial response rate 37%. There were 10 deaths after rATG (28.5%) and 1 after subsequent HSCT. Infections were the main cause of death in 9 of 10 patients. The best response rate was 60% for rATG and 67% for hATG. For rATG, overall survival at 2 years was 68%, compared with 86% for hATG (P = .009). Transplant-free survival was 52% for rATG and 76% for hATG (P = .002). On multivariate analysis, rATG (hazard ratio = 3.9, P = .003) and age more than 37 years (hazard ratio = 4.7, P = .0008) were independent adverse risk factors for survival. This study was registered at www.clinicaltrials.gov as NCT00471848.

Description: We evaluated the role of granulocyte colony-stimulating factor (G-CSF) in patients with severe aplastic anemia (SAA) treated with antithymocyte globulin (ATG) and cyclosporine (CSA). Between January 2002 and July 2008, 192 patients with newly diagnosed SAA not eligible for transplantation were entered into this multicenter, randomized study to receive ATG/CSA with or without G-CSF. Overall survival (OS) at 6 years was 76% ± 4%, and event-free survival (EFS) was 42% ± 4%. No difference in OS/EFS was seen between patients randomly assigned to receive or not to receive G-CSF, neither for the entire cohort nor in subgroups stratified by age and disease severity. Patients treated with G-CSF had fewer infectious episodes (24%) and hospitalization days (82%) compared with patients without G-CSF (36%; P = .006; 87%; P = .0003). In a post hoc analysis of patients receiving G-CSF, the lack of a neutrophil response by day 30 was associated with significantly lower response rate (56% vs 81%; P = .048) and survival (65% vs 87%; P = .031). G-CSF added to standard ATG and CSA reduces the rate of early infectious episodes and days of hospitalization in very SAA patients and might allow early identification of nonresponders but has no effect on OS, EFS, remission, relapse rates, and mortality. This study was registered at www.clinicaltrials.gov as NCT01163942.

Description: Introduction: The PETAL trial is a multicenter randomized controlled study for patients with aggressive lymphomas of diverse histologies (EudraCT 2006-001641-33, NCT00554164). In the study population as a whole interim PET (iPET) reliably predicted time to treatment failure (TTTF) and overall survival (OS). Interim PET-based treatment changes, however, had no impact on outcome (ASH 2014, abstract 391). Here we report the exploratory analysis for aggressive B cell lymphomas. Methods: Pts. aged 18 to 80 yrs. with newly diagnosed aggressive lymphomas and a positive baseline PET received 2 cycles of rituximab (R), cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) followed by iPET. The conditions of iPET were strictly defined: 3-week interval between the 2nd R-CHOP cycle and iPET to avoid inflammatory reactions (Eur J Nucl Med Mol Imaging 30:682, 2003), no G-CSF after the 2nd cycle to avoid altered glucose biodistribution (J Nucl Med 47:950, 2006), standardized uptake value (SUV)-based PET interpretation to improve reproducibility (favorable iPET response: reduction of maximum SUV by 〉 66 % compared to baseline; J Nucl Med 48:1626, 2007). Pts. with CD20+ lymphomas and a favorable iPET were randomized to receive 4 more cycles of R-CHOP or the same treatment plus 2 extra doses of R (part A of the trial). Pts. with an unfavorable iPET were randomized to continue R-CHOP for 6 additional cycles or receive 6 blocks of a more complex methotrexate-, cytarabine- and etoposide-based regimen originally designed for Burkitt lymphoma (Blood 124: 3870, 2014; part B). R was omitted in pts. with CD20- lymphomas. Sample size of the entire study population was based on the empirically derived assumption that treatment failure after 2 yrs. (TF: progression, relapse, treatment discontinuation due to toxicity, start of alternative therapy, death of any cause) could be improved from 80 % to 90 % in part A and from 30 % to 45 % in part B (alpha=0.05, power=0.8). Secondary endpoints included OS and toxicity. Results: Fifty-seven oncological centers and 23 nuclear medicine institutions participated in the trial. Between 2007 and 2012 1072 pts. were registered, and 862 (80.4 %) had a positive baseline PET, received 2 cycles R-CHOP, underwent iPET and were allocated to one of the post-iPET treatment arms detailed above. Reference pathology was available in 98 %, and median follow-up is 52 months. All in all, there were 779 patients with CD20+ aggressive B-cell lymphomas (90.4 % of all treated pts.) of whom 606 had diffuse large B-cell lymphoma (DLBCL), 42 primary mediastinal B-cell lymphoma (PMBCL) and 42 follicular lymphoma grade 3 (FL3). Interim PET was favorable in 691 pts. (88.7 %) and unfavorable in 88 pts. with CD20+ lymphomas (11.3 %). It was highly predictive of TTTF for CD20+ lymphomas in general and for each of the DLBCL, PMBCL and FL3 subgroups (Table). In CD20+ lymphomas and DLBCL, the iPET response predicted TF independently of the International Prognostic Index, and it was also predictive of OS. The groups of PMBCL and FL3 were too small for multivariate analyses. In part A, adding 2 extra doses of R failed to improve TTTF and OS in all histological entities. Separate analyses for subgroups defined by sex, age (〈 vs. 〉 60 yrs.) or a combination of the two showed no statistically significant benefit of extra doses of R in any of the subgroups. In pts. with an unfavorable iPET response, a switch from R-CHOP to the Burkitt regimen failed to improve TTTF or OS in CD20+ lymphomas in general (Figure) and in the DLBCL, PMBCL and FL3 subgroups. In part B, the Burkitt protocol was associated with more grade 3/4 leukopenia (82 % vs. 57 %, p=0.02), thrombocytopenia (59 % vs. 18 %, p=0.0001), infection (41 % vs. 16 %, p=0.017) and mucositis (39 % vs. 7 %, p=0.0007) than R-CHOP, but treatment-related mortality was similar in both arms (1 death each). Conclusion: In this large multicenter trial iPET proved highly predictive of outcome in pts. with CD20+ aggressive B-cell lymphomas, DLBCL, PMBCL or FL3 treated with R-CHOP. In pts. with a favorable iPET response, addition of 2 extra doses of R to 6 cycles R-CHOP failed to improve outcome in CD20+ lymphomas in general and in subgroups defined by histology, sex or age. In pts. with an unfavorable iPET response, switching to a more aggressive protocol also failed to improve outcome in any of the entities. Novel strategies are required for aggressive B-cell lymphomas failing to respond to the first 2 cycles of R-CHOP. Table Table. Figure Figure. Disclosures Duehrsen: Roche: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding. Giagounidis:Celgene Corporation: Consultancy. Grube:BMS, Sanofi: Consultancy. Klapper:Roche, Novartis, Amgen, Takeda: Research Funding. Hüttmann:Bristol-Myers Squibb, Takeda, Celgene, Roche: Honoraria; Gilead, Amgen: Other: Travel cost.

Description: Introduction: The PETAL trial is a multicenter randomized controlled study for patients with aggressive lymphomas of diverse histologies (EudraCT 2006-001641-33, NCT00554164). In the study population as a whole interim PET (iPET) reliably predicted time to treatment failure (TTTF) and overall survival (OS). Interim PET-based treatment changes, however, had no impact on outcome (ASH 2014, abstract 391). Here we report the exploratory analysis for peripheral T cell lymphomas (PTCL). Methods: Pts. aged 18 to 80 yrs. with newly diagnosed aggressive lymphomas and a positive baseline PET received 2 cycles of rituximab (R), cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) followed by iPET. R was omitted in pts. with CD20-negative lymphomas. The conditions of iPET were strictly defined: 3-week interval between the 2nd (R-)CHOP cycle and iPET to avoid inflammatory reactions (Eur J Nucl Med Mol Imaging 30:682, 2003), no G-CSF after the 2nd cycle to avoid altered glucose biodistribution (J Nucl Med 47:950, 2006), standardized uptake value (SUV)-based PET interpretation to improve reproducibility (favorable iPET response: reduction of maximum SUV by 〉 66 % compared to baseline; J Nucl Med 48:1626, 2007). PTCL pts. with CD20-negative lymphomas and a favorable iPET uniformly received 4 additional cycles of CHOP (part A of the trial). Pts. with an unfavorable iPET were randomized to continue CHOP for 6 additional cycles or receive 6 blocks of a more complex methotrexate-, cytarabine- and etoposide-based regimen originally designed for Burkitt lymphoma (Blood 124: 3870, 2014; part B). Sample size of the entire study population was based on the empirically derived assumption that treatment failure after 2 yrs. (progression, relapse, treatment discontinuation due to toxicity, start of alternative therapy, death of any cause) could be improved from 30 % to 45 % in part B (alpha=0.05, power=0.8). Secondary endpoints included OS and toxicity. Results: Fifty-seven oncological centers and 23 nuclear medicine institutions participated in the trial. Between 2007 and 2012 1072 pts. were registered, and 862 (80.4 %) had a positive baseline PET, received 2 cycles (R-)CHOP, underwent iPET and were allocated to one of the post-iPET treatment arms detailed above. Reference pathology was available in 98 %, and median follow-up is 52 months. All in all, there were 76 pts. (8.8 % of all treated pts.) with T-cell lymphomas of whom 21 had ALK+ anaplastic large cell lymphoma (ALCL), 13 ALK- ALCL, 18 angioimmunoblastic T-cell lymphoma (AITL) and 20 PTCL not otherwise specified (NOS). Interim PET was favorable in 57 pts. (75 %) and unfavorable in 19 pts. with T-cell lymphomas (25 %). It was highly predictive of outcome, TTTF and OS being significantly higher in part A than B (2-year probability for TTTF: 63 % vs. 21 %; univariate hazard ratio (HR) for B 3.4, 95 % confidence interval (CI) 1.8 - 6.4, p

Description: Abstract 496 Immunosuppression (IS) with ATG and Cyclosporine (CSA) is the treatment of choice for patients with severe aplastic anemia (AA) not eligible for hematopoietic stem cell transplantation. The role of additional growth factors such as G-CSF on long-term outcome is still a matter of debate. The Aplastic Anemia Working Party of the EBMT conducted a randomized controlled study comparing IS with ATG and CSA with or without G-CSF and with or without early retreatment at day 120 in case of nonresponse. The study was designed to identify a difference of 10% for overall survival (OS) and event free survival (EFS). Three hundred forty subjects were to be enrolled. From 2002 to 2008, 205 patients were randomized, but 13 had to be excluded (1 incorrect diagnosis; 12 no follow-up data); 192 were evaluable for analysis (95 with G-CSF; 97 without G-CSF). The median age of the patients was 46 years (2-81), 95 (49%) were males, 69 (36%) had very severe AA. There was no difference between both groups in respect of age, sex, severity of the AA, and number of transfusions before treatment. Horse ATG (Lymphoglobulin) was administered (15mg/kg/BW/d ×5 days), and CSA given orally at a dose of 5mg/kg/d. Patients randomized to receive G-CSF were given glycosylated rHuG-CSF from day 8 to 120 (150mg/m2/d, sc). OS at 6 years was 75%, it was 82% for patients with severe AA and 66% for patients with very severe AA (P=0.001). Survival decreased with increasing age from 100% (age 60 years) (P3 years) in the G-CSF group (P=0.01). There was no difference in respect of response rates between both groups. Overall 73% of patients with and 62% without G-CSF did respond to IS (P=0.488). Response rates at days 30, 60, 90 120, 150, 180, 240 and 360 were similar between the treatment groups. Fifty seven patients did not respond to first-line therapy, and 31 patients relapsed during the first year of treatment, without any difference between both groups. In conclusion, G-CSF given together with standard IS increases neutrophil counts, and decreases rate of infections and days of hospitalization, mainly in patients with very severe AA. G-CSF does not improve long-term outcome and has no impact on OS, EFS, remission, death and relapse rates. G-CSF may decrease infection risks when used as an adjunct to IS therapy. This has to be weighed against possibly higher risks of MDS/AML, as suggested by previous studies. Disclosures: Schrezenmeier: Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Description: Abstract 3434 Introduction: Several clinical trials established treatment with horse ATG (hATG) and cyclosporine A (CsA) as standard treatment of AA in patients (pts) who are not candidates for stem cell transplantation (SCT). In 2007 the hATG brand Lymphoglobulin® was withdrawn from the market. As the hATG brand ATGAM®, is not approved in Europe, hATG was replaced by rabbit ATG (rATG). Recently a large prospective randomized one-center study from NIH, USA comparing hATG ATGAM®/CsA and rATG Thymoglobulin®/CsA in untreated AA showed significantly lower response rates and survival with rATG. To obtain further information on rATG treatment in an unselected AA population, especially with a higher median of age and use of different rATG dosages we performed a retrospective data collection of first line rATG therapy on several centers. This shall reflect outcome after rATG in a real-world situation. Methods: Retrospective data collection and analysis of first line rATG treatment of AA after approval by Ethical Committee. Results: Up to now retrospective data of 64 pts from 18 centres in Germany were analysed. Characteristics of the pts: 30 male, 34 female; median age at time of therapy 54 years (6–80 years); 87.5% of pts had idiopathic AA. 51.6% of pts had severe AA, 32.8% very severe AA and 15.6% non-severe AA. Median granulocyte count was 0.3 G/l. 86% of the pts required red blood cell and 92% platelet transfusions. 56 of the evaluable pts received Thymoglobulin® and 5 pts Fresenius ATG S®. 52 of the 56 Thymoglobulin®-treated pts got this therapy in the years 2007–2011, i.e. not as deliberate primary choice of rATG but because hATG was no longer available. Median daily dose of Thymoglobulin® was 3.5 mg/kg (range from 2.5 – 3.75 mg/kg) for 5 days. 62 of 64 pts received additional immunosuppressive therapy with CsA and 19 of 64 pts received G-CSF. The median follow-up for surviving pts was 558.5 days (range, 78–3800 days). Response rates at time of best response of pts were CR in 10/58 pts (17%), PR in 18/58 pts (31%) and NR in 30/58 pts (52%) (only surviving patients with a minimum follow-up of 120 days were analyzed). Median interval to best response was 217 days. Response rate (PR+CR) was 16/33 (48.5%) in pts who received a Thymoglobulin® dose of 〉 3.5 –3.75 mg/kg/day versus only 4/14 (28.6%) group of 14 pts with a dose of 〉 2.5 to 〈 3.5 mg/kg/day (p=0.17; Fisher`s exact test). Relapses occurred in 3/28 responders and clonal evolution was observed in 3 pts (2 PNH, 1 MDS). Eighteen of 63 evaluable pts received allogenic SCT after ATG-therapy and were censored at the date of SCT. 23% of 44 pts without SCT died. In 6 of these 10 pts death was caused by infections. Other causes of death were bleeding, cardiac event, acute respiratory distress syndrome, adynamia. Overall probability of survival at 3 years was 75.8% (95% confidence interval (CI): 61.8 – 89.9%) and survival censored for SCT was 79.9% (CI: 66.0–92.8%). Survival was significantly better in responders (PR and CR) (94.1% at 3 years; CI: 82.9–100%) than in non-responders (58.0% at 3 years; CI 34.0 – 81.3%) (p=0.04; log-rank test). Adverse events were reported in 79.4% of 63 evaluable pts consisting of anaphylaxis/allergy in 27.3%, serum sickness in 12.7%, fever/chills in 34.5%, and bacterial/viral/fungal infections in 54.5% of pts. Conclusion: Response rate and survival after rATG+CsA in this retrospective analysis is lower than in historical controls (e.g. hATG+CsA treatment in previous controlled studies of the German AA Study Group and the EBMT AA Working Party; Frickhofen et al., Blood 2003; Tichelli et al., Blood 2011) and rate of (early) infections seem to be high. Our results are in accordance with recent reports from other groups. Additionally the results of this retrospective data analysis suggest a benefit for the patient group treated with a Thymoglobulin® dosage of 〉 3.5 –3.75 mg/kg/day compared to lower doses (〈 3.5 mg/kg/day). There is growing evidence that best results in terms of response and survival are obtained by hATG-based immunosuppression. hATG can not be replaced by rATG without negative impact on patient outcome. There is need for action to achieve availability of hATG worldwide. If hATG is not available, treatment with rATG should be considered instead of no treatment or treatment with CsA alone since still about half of the patients respond to rATG. Disclosures: Höchsmann: Alexion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Genzyme: Consultancy, Honoraria, Research Funding. Off Label Use: The use of the horse ATG ATGAM in Aplastic Anemia is off-label in Europe. At the moment no horse ATG with approval is available in Europe. Schrezenmeier:Genzyme: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria; Novartis: Consultancy, Research Funding.

Description: Abstract 4055 Recent clinical studies demonstrate the high potency of human regulatory T cells (Tregs) to control graft-versus-host disease following hematopoietic stem cell transplantation (SCT). Isolation of Tregs after recombinant G-CSF induced mobilization of stem cells would simplify the design of clinical trials in allogeneic SCT. However, there is growing evidence that G-CSF also exerts profound immune modulatory effects in the adaptive immune system. Therefore, we analyzed Tregs isolated by FACS based cell sorting from stem cell donors before (n=8) and after (n=13) G-CSF administration regarding their phenotype, stability, functional and expansion properties. Absolute CD4+ T cell (3.2 fold increase of mean after G-CSF; p