A Phase 3, Single-Arm, Prospective Study of Remestemcel-L, Ex Vivo Culture-Expanded Adult Human Mesenchymal Stromal Cells for the Treatment of Pediatric Patients Who Failed to Respond to Steroid Treatment for Acute Graft-versus-Host Disease.

Steroid-refractory acute graft-versus-host disease (SR-aGVHD) following hematopoietic cell transplantation (HSCT) is associated with poor clinical outcomes. Currently, there are no safe and effective therapies approved for use in the pediatric population under the age of 12 years. Accordingly, there is an urgent need for new treatments that are safe, well tolerated, and effective in managing this debilitating and potentially fatal complication of HSCT. In early phase clinical trials, mesenchymal stromal cells (MSCs) have demonstrated efficacy in the treatment of acute GVHD (aGVHD) in pediatric patients. We now report the results of a phase 3, prospective, single-arm, multicenter study (NCT02336230) in 54 children with primary SR-aGVHD who were naive to other immunosuppressant therapies for aGVHD treated with MSC product (remestemcel-L) dosed at 2 × 106 cells/kg twice weekly for 4 weeks. Remestemcel-L therapy significantly improved day 28 overall response rate (OR) compared with the prespecified control OR value of 45% (70.4% versus 45%, P = .0003). The statistically significant OR (70.4%) was sustained through day 100, including an increase in complete response from 29.6% at day 28 to 44.4% at day 100. Overall survival was 74.1% at day 100 and 68.5% at day 180. Overall response in all participants at day 28 was highly predictive of improved survival through 180 days, and survival was significantly greater in day 28 responders compared with nonresponders through day 100 (86.8% versus 47.1% for responders and nonresponders, respectively, P = .0001) and through day 180 (78.9% versus 43.8%, P = .003). Remestemcel-L was well tolerated with no identified infusion-related toxicities or other safety concerns. This study provides robust, prospective evidence of the safety, tolerability, and efficacy of remestemcel-L as first-line therapy after initial steroid failure in pediatric SR-aGVHD.

Parent proxy assessment of sibling quality of life following pediatric hematopoietic cell transplantation.

BACKGROUND: When a child undergoes hematopoietic cell transplantation (HCT), the impact extends to the entire family, including siblings. Assessment of the quality of life (QoL) of siblings is challenged by their general lack of availability for regular assessment by clinical providers. Thus, the use of parent proxy reporting may be useful. Our aim was to describe the QoL of siblings of HCT survivors, as reported by their parents, as well as to identify parent and family factors associated with lower sibling QoL. METHODS: A cross-sectional study was utilized to assess parent-reported QoL of the HCT recipient's sibling (Short Form (SF)-10 Health Survey for Children and the Pediatric Symptom Checklist (PSC)-17). Parent QoL was assessed using the SF-12. Multivariable linear regression was used to explore hypothesized predictors of sibling QoL, including parent QoL, family impact/function (Impact on Family Scale, Family Adaptability and Cohesion Evaluation Scales, IV, and a question asking about financial problems) while adjusting for demographic and HCT characteristics. RESULTS: Ninety-seven siblings (55% males) with a mean age of 12 years (standard deviation [SD] 4 years) were assessed, representing HCT survivors, who were an average of 5 years (SD 4 years) post-HCT. Neither sibling psychosocial (mean 49.84, SD 10.70, p = 0.87) nor physical health scores (mean 51.54, SD 8.42, p = 0.08) differed from norms. Parent proxies reported behavioral/emotional problems (PSC-17 total score > 15) in 24% of siblings. While parental ratings of their own physical health (SF-12 were higher than norms (mean 53.04, SD 8.17, p = 0.0005), mental health scores were lower (mean 45.48, SD 10.45, p < 0.0001). In multivariable analysis, lower parent emotional functioning and adverse family function were associated with lower sibling QoL, as reported by parents. CONCLUSIONS: While proxy-reported QoL of siblings did not differ significantly from normative data, both parent QoL and family function were associated with sibling QoL. Future research is needed to understand how siblings themselves perceive their QoL following HCT.

Safety, Pharmacokinetics, and Efficacy of Palifermin in Children and Adolescents with Acute Leukemias Undergoing Myeloablative Therapy and Allogeneic Hematopoietic Stem Cell Transplantation: A Pediatric Blood and Marrow Transplant Consortium Trial.

Currently, effective pharmacologic treatment to reduce severe oral mucositis (OM) resulting from high-dose myeloablative cytotoxic therapy in the pediatric population is not available. Palifermin has been proven to decrease the incidence and duration of severe OM in adults with hematologic malignancies undergoing hematopoietic stem cell transplantation (HSCT). In the pediatric population, however, data on palifermin treatment are limited. A phase I dose-escalation study of palifermin in pediatric patients with acute leukemias undergoing myeloablative HSCT with total body irradiation, etoposide, and cyclophosphamide was performed to determine a safe and tolerable dose and to characterize the pharmacokinetic (PK) profile and efficacy of palifermin. Twenty-seven patients in 3 age groups (1 to 2, 3 to 11, and 12 to 16 years) and 3 dose levels (40, 60, and 80 µg/kg/day) were studied. There were no deaths, dose-limiting toxicities, or treatment-related serious adverse events. Long-term safety outcomes did not differ from what would be expected in this population. PK data showed no differences between the 3 age groups. Exposure did not increase with increase in dose. The maximum severity of OM (WHO grade 4) occurred in 6 patients (22%), none of whom was in the 80-µg/kg/day dosing group. This study showed that all doses were well tolerated and a good safety profile in all 3 pediatric age groups was seen.

Sorafenib treatment following hematopoietic stem cell transplant in pediatric FLT3/ITD acute myeloid leukemia.

BACKGROUND: FLT3/ITD is associated with poor outcomes in adult and pediatric acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (HSCT) can improve cure rates, however relapse is still common. Recent studies demonstrate the activity of FLT3 inhibitors, including sorafenib, in targeting the underlying mutation. PROCEDURE: We conducted a retrospective study of 15 pediatric patients with FLT3/ITD+ AML treated with sorafenib within 18 months after receiving HSCT. Sorafenib was administered either as prophylaxis in patients considered at very high risk for relapse (n = 6) or at the time of disease recurrence (n = 9). RESULTS: Sorafenib was initiated at a median of 100 days post HSCT. Overall, 11/15 (73%) of patients experienced medically significant toxicities. Among patients who experienced toxicity, 6/11 (55%) received treatment at doses above what was later determined to be the maximum tolerated dose of sorafenib for pediatric leukemia. Importantly, sorafenib did not appear to exacerbate graft versus host disease. Our findings suggest that sorafenib may be of particular efficacy in patients with minimal residual disease (MRD); all patients who received sorafenib for MRD immediately prior to transplant or with emergence post-HSCT are alive and remain in complete remission at a median of 48 months post HSCT. CONCLUSIONS: Our case series suggests that sorafenib administration is feasible and tolerable in pediatric FLT3/ITD+ AML patients early post HSCT. Ongoing prospective controlled studies are needed to further define the dosing of sorafenib in the post-HSCT period and to determine the optimal context for this treatment approach.

Successful cord blood transplantation in a patient with malignant infantile osteopetrosis and hemophilia.

MIOP is a congenital disorder of osteoclast differentiation or dysfunction. Inadequate bone resorption by osteoclasts results in a spectrum of complications including hypocalcemia, osteosclerosis, marrow failure, extramedullary hematopoiesis, hydrocephalus, visual deficits, and eventual mortality. Early diagnosis and timely HCT is a recommended treatment approach for select patients prior to the development of end-organ damage. A comorbid bleeding disorder presents a unique challenge in the setting of MIOP and cord blood HCT given the additional risk factors for bleeding including delayed engraftment, a high risk of developing sinusoidal obstruction syndrome, and potential need for emergent invasive procedures. To our knowledge, this is the first report of a patient with an autosomal recessive form of MIOP who successfully underwent a cord blood HCT complicated by the presence of mild hemophilia A and HCT-related complications including delayed engraftment, sinusoidal obstruction syndrome, and need for multiple invasive procedures (e.g., ventriculostomy, tracheostomy) without clinically significant bleeding. Given the underlying diagnosis of MIOP and need for HCT, the challenge of mitigating the significant risk of bleeding in a patient with a comorbid bleeding disorder is discussed.

How I treat childhood CML.

Chronic myeloid leukemia (CML) is composed of 3% of pediatric leukemias, making evidence-based recommendations difficult. Imatinib has revolutionized the treatment for adult CML by eliminating allogeneic stem cell transplantation for almost all patients in chronic phase. Shown effective in pediatric CML, imatinib and successive tyrosine kinase inhibitors (TKI) have provided more therapeutic options. Because stem cell transplantation has been better tolerated in children and adolescents, the decision to treat by either TKI or transplantation is controversial. We present a recent case of a 12-month-old boy diagnosed with BCR-ABL(+) CML to highlight the controversies in treatment recommendations. We review the pediatric stem cell transplantation outcomes as well as the pediatric experience with imatinib and other TKIs. Finally, we compare the side effects as well as costs associated with allogeneic stem cell transplantation versus TKI therapy. We recommend that frontline therapy for pediatric CML in chronic phase is TKI therapy without transplantation. Patients in accelerated or blast crisis or who fail to reach landmarks on TKIs either because of intolerance or resistance should pursue stem cell transplantation. Although we recommend adopting adult clinical experience to guide therapeutic decision making, the issues of infant CML, drug formulation, pharmacokinetics, and adolescent compliance merit clinical investigation.

Randomized trial of hydroxychloroquine for newly diagnosed chronic graft-versus-host disease in children: a Children's Oncology Group study.

The Children's Oncology Group conducted a multicenter Phase III trial for chronic graft-versus-host disease (cGVHD). The double-blind, placebo-controlled, randomized study evaluated hydroxychloroquine added to standard therapy for children with newly diagnosed cGVHD. The study also used a novel grading and response scoring system and evaluated clinical laboratory correlates of cGVHD. The primary endpoint was complete response (CR) after 9 months of therapy. Fifty-four patients (27 on each arm) were enrolled before closure because of slow accrual. The CR rate was 28% in the hydroxychloroquine arm versus 33% in the placebo arm (odds ratio [OR] = 0.77, 95% confidence interval [CI]: 0.20-2.93, P = .75) for 42 evaluable patients. For 41 patients with severity assessment at enrollment, 20 (49%) were severe and 18 (44%) moderate according to the National Institutes of Health Consensus Conference global scoring system. The CR rate was 15% for severe cGVHD and 44% for moderate cGVHD (OR = 0.24, 95% CI: 0.05-1.06, P = .07). Although the study could not resolve the primary question, it provided important information for future cGVHD study design in this population.

Inflammatory polyps following successful HLA-matched cord blood transplantation in a patient with X-linked lymphoproliferative syndrome.

Gastrointestinal complications following HSCT are numerous and include a variety of issues resulting in hepatic, biliary, pancreatic, and intestinal compromise. In the context of an underlying state of immune dysregulation, novel complications may arise including autoimmunity. To our knowledge, this is the first report of a patient with XLP who was successfully treated with HSCT using an HLA-matched unrelated cord blood unit that was complicated by the development of inflammatory polyps of the colon. Given the underlying diagnosis of XLP and its associated immune dysregulation, the challenge of understanding unique gastrointestinal manifestations of autoimmunity following HSCT is discussed.

Correction of celiac disease after allogeneic hematopoietic stem cell transplantation for acute myelogenous leukemia.

Allogeneic hematopoietic stem cell transplantation has been shown to correct or improve a variety of autoimmune disorders. This has not been reported for celiac disease, but transmission to a hematopoietic stem cell transplantation recipient from a donor with celiac disease has been reported. We report a 12-year-old girl with celiac disease who was diagnosed with acute leukemia and received an allogeneic hematopoietic stem cell transplant. Her celiac disease resolved after the hematopoietic stem cell transplant.

Comparison of graft-versus-host-disease and survival after HLA-identical sibling bone marrow transplantation in ethnic populations.

The association of ethnicity with the incidence of graft-versus-host disease (GVHD) and other clinical outcomes after transplantation is controversial. We compared the results of HLA-identical sibling bone marrow transplantations for leukemia, performed between 1990 and 1999, among different ethnic populations, including 562 Japanese, 829 white Americans, 71 African Americans, 195 Scandinavians, and 95 Irish. Results for adults and children were analyzed separately. Multivariate analyses of adult patients showed that white Americans, African Americans, and Irish cohorts were at significantly higher risk for acute GVHD than Japanese or Scandinavian cohorts (relative risk [RR] = 1.77, P < .001; RR = 1.84, P < .006; RR = 2.22, P < .001, respectively). White Americans, African Americans, and Irish, but not Scandinavians, were at significantly higher risk for early (within 3 months of transplantation) transplant-related mortality (TRM) compared with Japanese (RR = 2.99, P < .001; RR = 5.88, P < .001; RR = 2.66, P < .009, respectively). No differences in the risk for chronic GVHD, relapse, and overall survival were noted. In the pediatric cohort (limited to Japanese and white Americans), white Americans were at significantly higher risk for acute (RR = 1.93; P = .04) and chronic (RR = 3.16; P = .002) GVHD. No differences in other clinical outcomes were noted. Our findings suggest that ethnicity may influence the risk for GVHD, though overall survival rates after transplantation remain similar.

Allogeneic bone marrow transplantation for children with acute myelocytic leukemia in first remission demonstrates a role for graft versus leukemia in the maintenance of disease-free survival.

In Children's Cancer Group (CCG) study 2891, patients who were recently diagnosed with acute myelocytic leukemia (AML) were assigned randomly to standard- or intensive-timing induction chemotherapy. Patients in first complete remission (CR1) and who had a human leukocyte antigen (HLA)-identical, related donor or a donor disparate at a single class I or II locus were nonrandomly assigned to receive a bone marrow transplant (BMT) by using oral busulfan (16 mg/kg) and cyclophosphamide (200 mg/kg). Methotrexate only was given for graft-versus-host disease (GVHD) prophylaxis. One hundred fifty patients received transplants. Grade 3 or 4 acute GVHD occurred in 9% of patients. Patients younger than 10 years had a lower incidence of grade 3 or 4 GVHD (4.6%) compared with patients 10 years or older (17.4%) (P =.044). Disease-free survival (DFS) at 6 years was 67% and 42% for recipients of intensive- and standard-timing induction therapies, respectively. Multivariate analysis showed that receiving intensive-timing induction therapy (P =.027) and having no hepatomegaly at diagnosis (P =.009) was associated with favorable DFS, and grades 3 and 4 acute GVHD were associated with inferior DFS. Multivariate analysis showed that grades 1 or 2 GVHD (P =.008) and no hepatomegaly at diagnosis (P =.014) were associated with improved relapse-free survival (RFS). Our results show that children older than 10 years are at higher risk for developing severe GVHD; acute GVHD is associated with favorable RFS.

Acute myeloid leukemia and myelodysplastic syndrome in children treated for cancer: comparison with primary presentation.

There has not been a reported series of children with therapy-induced myelodysplastic syndrome/acute myeloid leukemia (tMDS/tAML) who were treated systematically. This paper describes 24 children with tMDS/tAML who were assigned randomly to standard- or intensive-timing induction on protocol CCG 2891. Presenting features and outcomes of those children were compared with those of 960 patients with de novo MDS (62 patients) or AML (898 patients). Children with tMDS/tAML were older at presentation (P =.015), had lower white blood cell counts (P =.01), and were more likely to have MDS (21% vs 7%) (P =.02) and trisomy 8 (P =.06). Fewer had hepatomegaly (P =.02), splenomegaly (P =.03), hepatosplenomegaly (P =.02), or classic AML translocations [t(8;21), t(15;17), 16q22; P =.02]. They had a poorer induction rate (50% vs 72%, P =.016), overall survival (26% vs 47% at 3 years, P =.007), and event-free survival (21% vs 39% at 3 years, P =.023). Disease-free survival after achieving remission was similar (45% vs 53%, P =.868). Children with tMDS/tAML who received intensive-timing induction had better outcomes than those who received standard-timing induction (overall survival 32% vs 0%, P =.54). In this study, the latency period to development of tMDS/tAML was the same for presumed alkylator-induced as for topoisomerase-induced myeloid leukemia. The findings of this study confirm that most children with tMDS/tAML have disease resistant to current therapies. Standard-timing induction appears less effective for this population.

Prospective study of 90 children requiring treatment for juvenile myelomonocytic leukemia or myelodysplastic syndrome: a report from the Children's Cancer Group.

PURPOSE: We report the first large prospective study of children with myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukemia (JMML) treated in a uniform fashion on Children's Cancer Group protocol 2891. PATIENTS AND METHODS: Ninety children with JMML, various forms of MDS, or acute myeloid leukemia (AML) with antecedent MDS were treated with a five-drug induction regimen (standard or intensive timing). Patients achieving remission were allocated to allogeneic bone marrow transplantation (BMT) if a matched family donor was available. All other patients were randomized between autologous BMT and aggressive nonmyeloablative chemotherapy. Results were compared with patients with de novo AML. RESULTS: Patients with JMML and refractory anemia (RA) or RA-excess blasts (RAEB) exhibited high induction failure rates and overall remission of 58% and 48%, respectively. Remission rates for patients with RAEB in transformation (RAEB-T) (69%) or antecedent MDS (81%) were similar to de novo AML (77%). Actuarial survival rates at 6 years were as follows: JMML, 31% +/- 26%; RA and RAEB, 29% +/- 16%; RAEB-T, 30% +/- 18%; antecedent MDS, 50% +/- 25%; and de novo AML, 45% +/- 3%. For patients achieving remission, long-term survivors were found in those receiving either allogeneic BMT or chemotherapy. The presence of monosomy 7 had no additional adverse effect on MDS and JMML. CONCLUSION: Childhood subtypes of MDS and JMML represent distinct entities with distinct clinical outcomes. Children with a history of MDS who present with AML do well with AML-type therapy. Patients with RA or RAEB respond poorly to AML induction therapy. The optimum treatment for JMML remains unknown.