Unrelated Donor Transplantation in Children with Thalassemia using Reduced-Intensity Conditioning: The URTH Trial

Allogeneic hematopoietic stem cell transplantation (HSCT) can cure transfusion-dependent thalassemia (TDT). In a multicenter trial we investigated the efficacy of reduced-intensity conditioning (RIC) before unrelated donor (URD) HSCT in children with TDT. Thirty-three children, ages 1 to 17 years, received bone marrow (BM) or umbilical cord blood (UCB) allografts. Median time to neutrophil engraftment was 13 days (range, 10 to 25) and 24 days (range, 18 to 49) and platelet engraftment 23 days (range, 12 to 46) and 50 days (range, 31 to 234) after BM and UCB allografts, respectively. With a median follow-up of 58 months (range, 7 to 79), overall and thalassemia-free survival was 82% (95% CI, .64% to .92%) and 79% (95% CI, .6% to .9%), respectively. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) after BM and UCB allografts was 24% and 44%; the 2-year cumulative incidence of chronic extensive GVHD was 29% and 21%, respectively; 71% of BM and 91% of UCB recipients discontinued systemic immunosuppression by 2 years. Six patients who had Pesaro risk class 2 (n = 5) and class 3 (n = 1) died of GVHD (n = 3), viral pneumonitis (n = 2) and pulmonary hemorrhage (n = 1). Outcomes after this RIC compared favorably with URD HSCT outcomes for TDT and supported engraftment in 32 of 33 patients. Efforts to reduce GVHD and infectious complications are being pursued further.

Outcomes following autologous hematopoietic stem cell transplant for patients with relapsed Wilms' tumor: a CIBMTR retrospective analysis

Despite the dramatic improvement in the overall survival for patients diagnosed with Wilms’ tumor (WT), the outcomes for those that experience relapse have remained disappointing. We describe the outcomes of 253 patients with relapsed WT who received high-dose chemotherapy (HDT) followed by autologous hematopoietic stem cell transplant (HCT) between 1990 and 2013, and reported to the Center for International Blood and Marrow Transplantation Research (CIBMTR). The 5-year estimates for event free survival (EFS) and overall survival (OS) were 36% (95% CI; 29 – 43%) and 45% (95% CI; 38 – 51%) respectively. Relapse of primary disease was the cause of death in 81% of the population. EFS, OS, relapse and transplant-related mortality (TRM) showed no significant differences when broken down by disease status at transplant, time from diagnosis to transplant, year of transplant or conditioning regimen. Our data suggest that HDT followed by autologous HCT for relapsed WT is well tolerated and outcomes are similar to those reported in the literature. Since attempts to conduct a randomized trial comparing maintenance chemotherapy with consolidation versus high-dose chemotherapy followed by stem cell transplant have failed, one should balance the potential benefits with the yet unknown long-term risks. Since disease recurrence continues to be the most common cause of death, future research should focus on the development of consolidation therapies for those patients achieving complete response to therapy.

Secondary solid cancer screening following hematopoietic cell transplantation

Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients.

Clinical outcomes of patients with desmoplastic small round cell tumor of the peritoneum undergoing autologous HCT: a CIBMTR retrospective analysis

Desmoplastic small round cell tumor of the peritoneum (DSRCTP) is a rare, frequently fatal tumor. This retrospective study, based on CIBMTR registry data, describes the largest reported cohort of DSRCTP patients who have undergone Auto-SCT. The probabilities of disease-free survival (DFS) at 1 year for patients in CR and not in CR were 75% (95% confidence interval: 48-94%) and 35% (15-59%), respectively. The probability of OS at 3 years was 57% (29-83%) and 28% (9-51%) for patients in CR and not in CR, respectively. Median survival for the entire cohort was 31 months (36 months and 21 months for those in CR and not in CR, respectively). Engraftment at 42 days was 97% (88-100%). Treatment-related mortality was low, with only one death in the first 100 days. Auto-SCT is a tolerable approach in patients with DSRCTP, with the greatest benefit seen in those patients who obtain CR. For those not in CR, the median OS in this series is greater than previously reported (21 months vs 17 months), suggesting Auto-SCT is useful in prolonging DFS and OS, even in patients with residual or persistent disease pre-transplant.

A phase I/II study of CY and topotecan in patients with high-risk malignancies undergoing autologous hematopoietic cell transplantation: the St Jude long-term follow-up

Fifty-eight consecutive children with high-risk malignancies were treated with CY, and targeted topotecan followed by autologous hematopoietic cell transplantation (AHCT) in a phase I/II Institutional Review Board-approved study. Twelve participants enrolled in phase I; 5 received dose level 1 of topotecan 3 mg/m(2) per day, with subsequent doses targeted to total systemic exposure of 100±20 ng h/mL and CY 750 mg/m(2) per day. Seven participants received dose level 2. CY dose escalation to 1 g/m(2) per day was considered excessively toxic; one died from irreversible veno-occlusive disease and two experienced reversible hepatotoxicity. These adverse events halted further dose escalation. A total of 46 participants were enrolled in phase II; results are on the 51 participants who received therapy at dose level 1, the maximum tolerated dose. Diagnoses included neuroblastoma (26), sarcoma (9), lymphoma (8), brain tumors (5), Wilms (2) and retinoblastoma (1). Twenty participants (39.3%) were in CR1 at enrollment; median age was 5.1 years. Most common non-hematological grade III-IV toxicity was gastrointestinal (n=37). Neutrophil and platelet engraftment occurred at a median of 15 and 24 days, respectively. Twenty-six (51%) participants remain alive at a median of 6.4 years after AHCT. CY 3.75 g/m(2), and targeted topotecan followed by AHCT are feasible and produce acceptable toxicity in children with high-risk malignancies.

A novel approach for quantification of KIR expression in healthy donors and pediatric recipients of hematopoietic SCTs

The killer cell Ig-like receptor (KIR) expression repertoire may offer valuable information for hematopoietic SCT (HSCT). We designed a quantitative KIR RNAtype assay and used it to determine KIR gene expression in healthy donors and patients before HSCT. The specificity of the assay was ensured by specific primers and by electrophoretic distinction of PCR products of unique length. In 87 healthy donors, the KIR repertoire was broadly distributed (32 categories of profiles). There was an overall trend toward inverse correlation of KIR expression level and donor age. Age affected mainly the activating KIR families. Leukemia patients showed lower KIR expression before transplantation than healthy donors. Stem cell mobilization caused a transient increase of KIR expression. We conclude that KIR expression differs quantitatively with age and primary disease and is transiently altered by stem cell recruitment and selection.