related to MMA filed by the NIH on their behalf. Lina Li is an employee of LLN Consultant Inc. and founder of CELiD Biotechnologies Inc. GME is a consultant for Moderna Therapeutics, LogicBio Therapeutics, Horizon Pharma, and Natera; a data-monitoring committee member for BioMarin, Audentes Therapeutics, Amicus, RegenxBio, and NeuroVia; and an investigator on clinical trials for Aeglea, BioElectron, and Stealth Therapeutics. LHV is an inventor of AncAAV and other AAV technologies, which are licensed to various biotechnology and pharmaceutical entities. LHV is a consultant to a number of companies with gene therapy interest, including Selecta Biosciences and Lonza, licensees of AncAAV technology. CPV has received funding to support AAV gene therapy research for MMA from Selecta Biosciences and LogicBio Therapeutics.

Methylmalonic acidemia patients have complex rehabilitation needs that can be targeted to optimize societal independence and quality of life. Thirty-seven individuals with isolated MMA (28 mut, 5 cblA, 4 cblB), aged 2-33 years, were enrolled in a natural history study, and underwent age-appropriate clinical assessments to characterize impairments and disabilities. Neurological examination and brain imaging studies were used to document movement disorders and the presence of basal ganglia injury. A range of impairments and disabilities were identified by a team of physical medicine experts. Movement disorders, such as chorea and tremor, were common (n = 31, 83%), even among patients without evidence of basal ganglia injury. Joint hypermobility (n = 24, 69%) and pes planus (n = 22, 60%) were frequent and, in many cases, under-recognized. 23 (62%) patients required gastrostomy feedings. 18/31 patients >4 years old (58%) had difficulties with bathing and dressing. 16 of 23 school-aged patients received various forms of educational support. Five of the 10 adult patients were employed or in college; three lived independently. Unmet needs were identified in access to rehabilitation services, such as physical therapy (unavailable to 14/31), and orthotics (unavailable to 15/22). We conclude that patients with MMA are challenged by a number of functional limitations in essential activities of mobility, self-care, and learning, in great part caused by movement disorders and ligamentous laxity. Early assessment, referral, and implementation of age-appropriate rehabilitation services should significantly improve independence and quality of life.

Background Methylmalonic acidemia and intracellular cobalamin metabolism disorders represent a heterogeneous group of inborn errors of metabolism. Most patients will require diagnostic and/or therapeutic procedures frequently requiring sedation or anesthetic management due to neurological and neurocognitive impairments. It has been stated that propofol is contraindicated in this population. We report our experience with propofol administration in a large series of patients. Methods 28 patients (14 mut, 7 cblC, 3 cblA, 3 cblB, 1 cblG) aged 2–35.6 years enrolled in a natural history study (ClinicalTrials.gov identifier: NCT00078078) and required anesthetics for 39 diagnostic or therapeutic procedures. Data were collected on the anesthetic technique, perianesthetic course and adverse events related to propofol. Results Propofol was used as the sole induction agent in most cases (36/39) and as the primary maintenance agent in all cases. Infusion rates were 100–400 mcg.kg−1.min−1 (mean=214). Infusion duration was 60–325 min (mean=158) and total doses ranged between 270–3610 mg (mean=1217). Adverse events were recorded in 2 cases; neither appeared to be related to propofol administration. Conclusions Propofol is an effective, safe induction and maintenance agent for elective short procedures requiring anesthesia in patients with MMA and cobalamin metabolism disorders. Despite multiple comorbidities and propensity toward instability, those affected can receive anesthesia with an acceptable safety profile, if metabolically and hemodynamically stabilized prior to the event.

Graft-vs-host disease (GvHD) limits successful outcomes following allogeneic blood and marrow transplantation (allo-BMT). We examined whether the administration of human, bone marrow-derived, multipotent adult progenitor cells (MAPCs™) could regulate experimental GvHD. The immunoregulatory capacity of MAPC cells was evaluated in vivo using established murine GvHD models. Injection of MAPC cells on day +1 (D1) and +4 (D4) significantly reduced T-cell expansion and the numbers of donor-derived, Tumor Necrosis Factor Alpha (TNFα) and Interferon Gamma (IFNγ)-producing, CD4+ and CD8+ cells by D10 compared with untreated controls. These findings were associated with reductions in serum levels of TNFα and IFNγ, intestinal and hepatic inflammation and systemic GvHD as measured by survival and clinical score. Biodistribution studies showed that MAPC cells tracked from the lung and to the liver, spleen, and mesenteric nodes within 24 hours after injection. MAPC cells inhibited mouse T-cell proliferation in vitro and this effect was associated with reduced T-cell activation and inflammatory cytokine secretion and robust increases in the concentrations of Prostaglandin E2 (PGE2) and Transforming Growth Factor Beta (TGFβ). Indomethacin and E-prostanoid 2 (EP2) receptor antagonism both reversed while EP2 agonism restored MAPC cell-mediated in vitro T-cell suppression, confirming the role for PGE2. Furthermore, cyclo-oxygenase inhibition following allo-BMT abrogated the protective effects of MAPC cells. Importantly, MAPC cells had no effect on the generation cytotoxic T lymphocyte activity in vitro, and the administration of MAPC cells in the setting of leukemic challenge resulted in superior leukemia-free survival. Collectively, these data provide valuable information regarding the biodistribution and regulatory capacity of MAPC cells, which may inform future clinical trial design.

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival.Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end organ failure, as compared to only 20.9% of deaths in the reduced intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD were associated with worse OS. In addition, a diagnosis of therapy related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS.Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs.

Pediatric oncology patients are often iron overloaded, due to the multiple blood transfusions necessary during the course of chemotherapy. Our aim is to report the efficacy and safety of deferasirox, an oral iron chelator, in this patient group. Deferasirox was administered to 13 children with malignancies in remission and iron overload. Ferritin, blood urea nitrogen, creatinine, transaminases, and bilirubin were recorded at 4- to 8-week intervals, and hepatic and cardiac iron overload were assessed with magnetic resonance imaging before initiation of treatment. Deferasirox was administered for an average of 6 months (SD=4.5; range, 0.3 to 18.2). Two children presented with skin rash, 1 with gastrointestinal disturbances, and 1 with fully reversible acute renal failure. The mean monthly rate of change in ferritin levels was -10.8 μg/L before initiation of treatment (95% confidence interval [CI], -19.8 to -1.8; P=0.02) and -93.6 μg/L during deferasirox treatment (95% CI, -118.1 to -69.1; P<0.001). The difference in the monthly rate of change in ferritin levels before and after treatment initiation was -82.8 μg/L (95% CI, -111.6 to -53.9; P<0.001). Deferasirox was effective in reducing the iron burden. The adverse effects were easily monitored and managed. Further studies are warranted to investigate the effect of deferasirox on mortality and morbidity in this population.

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