Khan, Shakila P.

Abstract Introduction: Early lymphocyte recovery predicts outcome in adults undergoing high dose chemotherapy followed by autologous stem cell transplantation for a variety of malignancies (Porrata et al; 2001, 2002, 2005). Whether rate of lymphoid recovery is predictive of outcome post-hematopoietic stem cell transplantation (HSCT) in children and young adults has not been studied. Objective: To explore the association between early ALC recovery and survival in children and young adults undergoing allogeneic and autologous (HSCT) for leukemia or lymphoma. Methods: Retrospective chart review was performed for all consecutive patients (age 6 months to 21 years) undergoing first HSCT for hematologic malignancies and lymphomas at Mayo Clinic, Division of Pediatric Hematology/Oncology from 1995 to 2004. Day 15 and day 28 ALC were calculated for all patients. The primary end point was 1-year relapse free (RFS) and overall survival (OS). To explore the association between ALC and primary outcome, patients were stratified in 2 groups: ≥ or < than median ALC and Kaplan Meier survival curves were generated for both the groups and compared with the log-rank test. Matched related donor (MRD), matched unrelated donor (MUD) and haploidentical (as one group) and autologous transplantations were analyzed separately. Results: There were a total of 50 patients. 28 received MRD, 2 MUD, 10 haploidentical and 10 autologous transplant. The underlying malignancies were AML n =25, Biphenotypic Leukemia n=1, ALL n =7, NHL n=3, HD n=7, JMML n=5, CML n=2, CLL n=1). No patient was lost to follow up during that time and data was available for all except (day 28 ALC) for one patient. The 1-year RFS and OS rate was the same; 81% for the MRD, 50% for MUD and haploidentical and 70% for autologous transplant populations, respectively. In patients receiving MRD transplants, higher ALC at either day 15 or day 28 post transplantation was associated with better, albeit statistically non-significant, RFS/OS rates at 1 year (85% for ≥ median (0.23) vs. 78% for < median p=0.69 and 86% for ≥ median (0.47) vs. 77% for < median p= 0.59 respectively). Opposite results were observed for MUD and Haploidentical transplantation group (33% for ALC ≥ median (0.05) at day 15 vs. 67% for < median p=0.2, 33% for ALC ≥ median (0.35) at day 28 vs. 66% for < median p=0.28) and for autologous transplantations (67% for ALC ≥ median (0.23) at day 15 vs. 75% for < median p=0.68, 40% for ALC ≥ median (0.48) at day 28 vs. 100% for < median p=0.07). Conclusions: Our data generated conflicting findings of the association between ALC and RFS/OS in different patient populations undergoing HSCT. However, our results are limited by the small sample size. Further collaborative studies are needed to explore this association.

Abstract Background: Ring sideroblasts (RS) are erythroid precursors with perinuclear mitochondrial iron accumulation seen in clonal disorders, such as myelodysplastic syndromes (MDS), and non-clonal conditions, including copper deficiency, lead poisoning, and congenital sideroblastic anemias (CSAs). CSAs involve a broad clinical and pathological spectrum related to mutations in ALAS2, ABCB7, etc. or mitochondrial aberrations (Pearson Syndrome; Myopathy, Lactic Acidosis and Sideroblastic Anemia (MLASA); etc.). MDS-RS is often associated with SF3B1 mutations, which have not been reported in other SAs. This study sought to further describe the characteristics and outcomes of patients with CSAs. Methods: After due IRB approval, we retrospectively identified all patients with a CSA diagnosis seen at our institution from 1990-2014. All bone marrow (BM) slides were re-reviewed to confirm the presence of RS. Secondary causes of SA were excluded. Genetic testing on the BM specimen was carried out when possible through research collaborations with the Boston Children's Hospital. Data was retrospectively extracted and is reported in Table 1. Data was analyzed based on the presence or absence of mitochondrial inheritance. Results: Seventeen patients with CSA were identified, 3 (17.6%) with mitochondrial inheritance. In the non-mitochondrial inheritance group, the median age at diagnosis was 29 years (range, 1-61 years). Six (42.9%) were males. At a median follow-up of 119 months (range, 1-401 months), 1 (7.1%) death was documented. The median overall survival (OS) has not been reached. Six of 14 (42.9%) underwent genetic testing, and a mutation was identified in 4 (ALAS -2, FECH -1, and a novel mutation, currently being validated). Six of 6 (100%) samples analyzed for SF3B1 mutations were negative. Median laboratory values at diagnosis included hemoglobin 9.5 g/dL, MCV 85.8, WBC 6.4, and platelets 297,000. Three (21.4%) patients had splenomegaly. Nine (64.3%) had iron overload; 3 (33%) were treated with iron chelation therapy, with only 1 documented response (≥ 500 µg/L reduction in serum ferritin). Twelve (85.7%) were treated with pyridoxine. Outcomes of pyridoxine treatment are described in Table 1. Three of 14 (21.4%) received red blood cell transfusions, and 3 (21.4%) received erythropoiesis stimulating agents (ESA). One (7.1%) patient underwent allogeneic stem cell transplant. Three patients had SAs of mitochondrial inheritance; aberrations were identified in 2 (YARS2 and a 4 kilobase mitochondrial deletion). In this group, the median age at diagnosis was 2 years (range, 1-13 years), and all were males. At a median follow-up of 173 months (range, 119-329 months), 2 (66.7%) deaths were documented. Median laboratory values at diagnosis included hemoglobin 9.0 g/dL, MCV 97.0, WBC 5.2, and platelets 175,000. Conclusions: Congenital SAs are rare, and the majority are of non-mitochondrial inheritance. The molecular basis for disease can be ascertained in less than 50% of patients. Unlike MDS with RS, CSAs are not characterized by the SF3B1 mutation, which may be used to establish clonality. With appropriate supportive care measures, survival for non-mitochondrially inherited CSA remains favorable. Table 1. Demographics and Outcomes for 17 Patients with CSA Age at Diagnosis (Years) Gender Molecular Mutation Additional Features Pyridoxine Response Iron Overload Survival (Months) Outcomes Non-Mitochondrial Inheritance 5 M R452H in ALAS2 N Y2 Y 173 Alive3 3 M Mutation being validated Splenomegaly Y2 Y 254 Alive3 6 M Unknown, PTPN11, ALAS 2, ABCB7 negative Splenomegaly N Y 137 Alive, status-post transplant 29 F Unknown1 N N/A N 131 Alive3 41 F Unknown1 N Y2 N 83 Alive4 40 M Promoter mutation in ALAS2 Splenomegaly N N 106 Alive4 31 F Unknown1 N N Y 401 Deceased 54 M Unknown1 N Lost to follow-up Y 1 Alive3 3 M FECH N N/A N 189 Alive3 1 F SCAD -VUS N Lost to follow-up Y 13 Alive3 29 F Unknown1 N N Y 205 Alive3 58 F Unknown1 N N Y 47 Alive, unknown transfusion status 61 F Unknown1 N Y2 Y 58 Alive3 23 F Unknown1 Alpha-thalassemia-2-trait Y2 N 37 Alive3 Mitochondrial Inheritance 13 M YARS2 MLASA N Y 329 Alive4 2 M Unknown, mitochondrial deletions and ABCB7 negative Myopathy, Ataxia N/A N 173 Deceased 1 M 4 kilobase mitochondrial deletion Pearson Syndrome, B cell lymphoma Y2 N 119 Deceased 1No molecular testing performed 2Sustained hemoglobin response of ≥ 1 g/dL over baseline for ≥ 12 weeks 3Transfusion-independent 4Transfusion-dependent Disclosures Steensma: Incyte: Consultancy; Onconova: Consultancy; Amgen: Consultancy; Celgene: Consultancy.

Abstract Background: Pediatric Anti-Phospholipid Syndrome (APS) is the most commonly acquired state of hypercoagulability in children, and is defined by venous and/or arterial thrombosis in the presence of circulating anti-phospholipid antibodies (aPLs) (most commonly lupus anticoagulant (LA), anticardiolipin antibody (aCL) and anti-β2-glycoprotein antibody (aβ2GP)). Catastrophic APS (CAPS) is a rare manifestation of APS, with thrombosis of multiple vessels that can lead to multi-system organ failure. Purpose: To determine the thromboses outcomes and factors predisposing to the risk of thrombotic recurrence in pediatric patients with a diagnosis of APS. Methods: Retrospective review of patients between the ages of 0-21 years diagnosed and treated with APS from 1997-2013 at our institution. Clinical data and long-term outcomes of these patients were reviewed. Exclusion criteria included neonatal APS and thrombosis with fetal loss. Statistical tests were performed using JMP software (© 2014 SAS Institute Inc., North Carolina, US). Associations between categorical variables were tested using chi-square test or Fisher’s exact test when required. Differences were considered statistically significant if p<0.05. Results: The study identified 23 patients (12 female; 11 male). Three patients with CAPS were identified and excluded from the analysis (3 female). Gender distribution for primary and secondary APS was similar (5 female/6 male primary APS; 4 female/5 male secondary APS). The median follow up period was 3.2 years (range; 0.01 – 16.87 years ). Median age at diagnosis of first episode of thrombosis was 16.16 years (range; 6.05 – 20.6 years). Nine patients (45%) with secondary APS had underlying autoimmune disease or malignancy (7 systemic lupus erythematosus, 1 ulcerative colitis, 1 Non-Hodgkin Lymphoma) and the remaining 11 patients were diagnosed as primary APS. Arterial and venous thrombosis occurred as the first thrombotic event in 7 (35%) and 13 (65%) patients, respectively. Lower extremity deep vein thrombosis (DVT) was the most frequent thrombotic event 11/20 (55%), followed by pulmonary embolism 7/20 (35%), ischemic stroke 4/20 (20%), lower extremity arterial thrombosis 3/20 (15%), upper extremity DVT 2/20 (10%), and IVC thrombosis 2/20 (10%). Recurrent or progressive thrombotic events occurred in 12/20 patients (60%). Of those, 7 were venous (58%), 5 were arterial (42%). At the time of recurrence, 3 patients were fully anticoagulated, (INR 2.5-3.5) versus 9 who were subtherapeutic (INR<2.0). Recurrent/progression thrombotic events occurred at the original site of thrombosis in 8 patients (3 arterial, 5 venous) while the remaining 4 recurrent thrombotic events occurred at other sites than the primary site. Overall venous and arterial thrombotic events were no different among primary or secondary APS (p=0.88). Thrombosis recurrence/progression risk at the original site or distant site was no different among primary or secondary APS (p=0.22 and p=0.30 respectively). Risk of recurrence/progression was not associated with subtherapeutic levels of anticoagulation (p=0.08), or presence of residual thrombosis at primary site at the time of recurrence (p=0.48). Conclusion: Recurrence and/or progression of thrombosis in APS occurred in 60% of the patients in our cohort, with 25% of the thrombosis recurrences occurring despite documented therapeutic anticoagulation in these patients. In contrast to other studies, our APS cohort demonstrated a higher rate of recurrence with other groups reporting thrombosis rates of recurrence such as 19-25%. Our cohort demonstrated similar rates of primary and secondary APS among female patients, in contrast to other studies suggesting higher rates of secondary APS in females. Potential risk factors such as primary versus secondary APS, subtherapeutic anticoagulation, and residual thrombosis from primary thrombotic event were not found as significant risk factors for thrombosis recurrence. Larger pediatric APS studies are needed in order to address other potential risk factors for thrombosis (ie obesity, inherited thrombophilia, intensity of anticoagulation, immune suppression approach for secondary APS), in order to establish treatment strategies for the prevention of recurrent thrombosis. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 4651 Introduction Graft versus host disease remains a major cause of mortality and morbidity following matched unrelated hematopoietic stem cell transplantation. Campath-1H (Alemtuzumab) is a humanized monoclonal antibody to CD52, an antigen expressed on T and B lymphocytes, monocytes and natural killer cells and is thought to reduce GVHD incidence through in vivo T cell depletion. Through the same mechanism it can potentially increase the risk of relapse by reducing the graft vs. leukemia effect and also possibly increase the risk of infection due to delayed immune recovery. This study looks at our experience with Campath-1H substituted in place of the conventional anti-thymocyte globulin (ATG) in our transplant conditioning regimen. Patients and Methods This retrospective case study included 17 pediatric (9 male; 8 female) matched unrelated bone marrow transplants done in our institution between January 2003 and June 2009 with Campath-1H as part of the pretransplant conditioning regimen. The primary transplant indication was leukemia/lymphoma (n=9), MDS/ MDS evolving into AML (n= 3), severe aplastic anemia (n=4) and Fanconi anemia (n=1). The conditioning regimen included Campath-1H given with cytoxan/ total body irradiation (TBI) in 14 patients, fludarabine/ TBI in 2 patients, and melphalan/ fludarabine in 1 patient. Campath-1H dosing was body weight based: 3mg (if between 5-15kg), 5 mg (if between 16-30kg) and 10 mg (if >30 kg) and 3 doses were administered when underlying condition was a malignancy and 4 doses when it was a bone marrow failure state. The last dose was given at least 24 hours prior to the bone marrow/ peripheral stem cell infusion. GVHD prophylaxis was with tacrolimus/methotrexate (n=12), tacrolimus (n=4) and cyclosporine/methotrexate (n=1). Standard institutional infectious prophylaxis was followed. Results The median age at transplant was 12.2 years (range; 0.7-19.7 years). All but one patient engrafted with a median of 21 days (range; 14-25 days). 5 out of 17 developed Grade I-II acute GVHD which resolved with steroids. No patient developed chronic GVHD. One patient had a CMV reactivation but no patient developed active CMV disease. 4 patients had varicella one of whom died of disseminated infection (day +376). The same patient also had adeno viral infection and BK viremia. 1 patient developed PCP pneumonia and retinal toxoplasmosis. 5 patients (6 transplants) relapsed (range; 40-641 days) with 3 relapsing within +100 days. 1 patient developed PTLD which was successfully treated with rituximab. Of the 4 patient deaths 3 were due to relapse and one due to disseminated varicella infection. The median follow-up time was 719 days (range; 147-2175 days). Overall survival as calculated using the Kaplan-Meir analysis was 100 % at 100 days and 94% at 1 year. Event free survival censoring for death, relapse and rejection was 76% at 100 days and 64% at 1 year. Conclusions Based on our experience, Campath-1H used as part of pretransplant conditioning regimen in pediatric matched unrelated transplants seems to reduce the risk of serious GVHD. This is in concordance with other published literature. T cell depletion is considered to increase the risk of life threatening infections. Our study had one infection related death. There were no patients with active CMV disease. This may in part be attributed to strict prophylactic measures and increased surveillance. Longer duration of follow-up is required to adequately analyze the relapse rates. Also, given our small patient numbers the effect of primary disease state and stage on relapse could not be assessed. Larger studies in the pediatric population with longer duration of follow-up comparing Campath-1H with conventional regimens are required to further assess its role with regards to graft vs. leukemia effect and also to establish if the decreased incidence of GVHD is sustained in larger cohorts. Disclosures: No relevant conflicts of interest to declare.

AbstractHSTCL is a highly aggressive malignancy with a poor prognosis. Case series and accounts have reported the use of different chemotherapy regimens with diverse patient outcomes. Most long‐term survivors had undergone high‐dose chemotherapy with autologous or allogeneic HCT. We describe two pediatric patients with HSTCL who were treated with chemotherapy followed by allogeneic HCT. Both patients are alive and in complete remission 2 and 8 years after therapy. Multiagent chemotherapy followed with allogeneic HCT seems to provide patients who have chemotherapy‐sensitive disease a long‐term disease‐free survival.

The risk of viral infections and reactivation occurring in the setting of pediatric allogeneic hematopoietic stem cell transplantation is a concern in the pediatric patient, especially with the use of Alemtuzumab (Campath) as a conditioning agent. The purpose of this study was to determine the incidence of Epstein-Barr virus posttransplant lymphoproliferative disorder (EBV-PTLD), cytomegalovirus (CMV), and adenovirus among pediatric recipients of alemtuzumab at our institution. We found that EBV-PTLD occurred in 2.1% of transplants (1 matched unrelated donor [MUD] recipient), CMV reactivation occurred in 12.5% of transplants (4 MUD and 2 matched related donor [MRD] recipients) with disseminated CMV in 2.1% of cases (1 MRD recipient), and adenovirus infection occurred in 8.3% of the total transplants (2 MUD and 2 MRD recipients). Alemtuzumab continues to be used as a method of graft-versus-host disease and graft failure prevention among pediatric recipients of hematopoietic stem cell transplantation and seems to be safer than previously reported. At our institution, alemtuzumab has not increased the risk for EBV-PTLD, CMV infection, or adenovirus.

AbstractLate‐onset HC is a well‐recognized complication associated with cyclophosphamide/acrolein‐induced toxicity. It poses a management challenge when hyperhydration and bladder irrigation do not result in clinical improvement as desired. The data regarding use of hyperbaric oxygen therapy (HBO2) as an early treatment modality in this clinical setting are limited. We present 2 cases, that were refractory to hyperhydration and bladder irrigation but responded to HBO2. They were treated with 20‐30 daily sessions over weekdays with 100% oxygen for 90 minutes at 2 atmospheric pressure units (2 atm). Both patients reported improved symptoms within the first 15 sessions, and hematuria diminished by 20 sessions. Hyperbaric oxygen is a less invasive, outpatient therapy that is effective for treatment of HC and is tolerated well by young patients.

High-dose methotrexate has been a treatment for osteosarcoma; however, its nephrotoxic effects are considerable. Carboxypeptidase-G2 (glucarpidase) was approved by the US Food and Drug Administration in 2012 for treatment of toxic methotrexate levels. We report our experience using glucarpidase under compassionate use before Food and Drug Administration approval in 2 patients who had delayed methotrexate clearance and prolonged kidney injury despite glucarpidase administration. Our results show that patients with methotrexate toxicity may require repeated doses of glucarpidase in addition to supportive measures, such as dialysis.