Non-enzymatic degradation of aliphatic Brassicaceae isothiocyanates during aqueous heat treatment.

Glucosinolate-derived isothiocyanates are valuable for human health as they exert health promoting effects. As thermal food processing could affect their levels in a structure dependent way, the stability and reactivity of 12 Brassicaceae isothiocyanates during aqueous heating at 100 °C and pH 5-8 were investigated. The formation of their corresponding amines and N,N'-dialk(en)yl thioureas was quantified. Further, the potential to form odor active compounds was investigated by HRGC-MS-olfactometry. A strong structure-reactivity relationship was found and shorter side chains and electron withdrawing groups increase the reactivity of isothiocyanates. 3-(Methylsulfonyl)-propyl isothiocyanate was least stable. The main products are the corresponding amines (up to 69% recovery) and formation of N,N'-dialk(en)yl thioureas is only relevant at neutral to basic pH values. Apart from allyl isothiocyanate also 3-(methylthio)propyl isothiocyanate is precursor to many sulfur-containing odor active compounds. Thus, the isothiocyanate-structure affects their levels but also contributes to the flavor of boiled Brassicaceae vegetables.

ImSpect: Image-driven self-supervised learning for surgical margin evaluation with mass spectrometry.

PURPOSE: Real-time assessment of surgical margins is critical for favorable outcomes in cancer patients. The iKnife is a mass spectrometry device that has demonstrated potential for margin detection in cancer surgery. Previous studies have shown that using deep learning on iKnife data can facilitate real-time tissue characterization. However, none of the existing literature on the iKnife facilitate the use of publicly available, state-of-the-art pretrained networks or datasets that have been used in computer vision and other domains. METHODS: In a new framework we call ImSpect, we convert 1D iKnife data, captured during basal cell carcinoma (BCC) surgery, into 2D images in order to capitalize on state-of-the-art image classification networks. We also use self-supervision to leverage large amounts of unlabeled, intraoperative data to accommodate the data requirements of these networks. RESULTS: Through extensive ablation studies, we show that we can surpass previous benchmarks of margin evaluation in BCC surgery using iKnife data, achieving an area under the receiver operating characteristic curve (AUC) of 81%. We also depict the attention maps of the developed DL models to evaluate the biological relevance of the embedding space CONCLUSIONS: We propose a new method for characterizing tissue at the surgical margins, using mass spectrometry data from cancer surgery.

From quantitative metrics to clinical success: assessing the utility of deep learning for tumor segmentation in breast surgery.

PURPOSE: Preventing positive margins is essential for ensuring favorable patient outcomes following breast-conserving surgery (BCS). Deep learning has the potential to enable this by automatically contouring the tumor and guiding resection in real time. However, evaluation of such models with respect to pathology outcomes is necessary for their successful translation into clinical practice. METHODS: Sixteen deep learning models based on established architectures in the literature are trained on 7318 ultrasound images from 33 patients. Models are ranked by an expert based on their contours generated from images in our test set. Generated contours from each model are also analyzed using recorded cautery trajectories of five navigated BCS cases to predict margin status. Predicted margins are compared with pathology reports. RESULTS: The best-performing model using both quantitative evaluation and our visual ranking framework achieved a mean Dice score of 0.959. Quantitative metrics are positively associated with expert visual rankings. However, the predictive value of generated contours was limited with a sensitivity of 0.750 and a specificity of 0.433 when tested against pathology reports. CONCLUSION: We present a clinical evaluation of deep learning models trained for intraoperative tumor segmentation in breast-conserving surgery. We demonstrate that automatic contouring is limited in predicting pathology margins despite achieving high performance on quantitative metrics.

Time from diagnosis to treatment has no impact on survival in newly diagnosed acute myeloid leukemia treated with venetoclax-based regimens.

In newly diagnosed acute myeloid leukemia, immediate initiation of treatment is standard of care. However, deferral of antileukemic therapy may be indicated to assess comorbidities or pre-therapeutic risk factors. We explored the impact of time from diagnosis to treatment on outcomes in newly diagnosed acute myeloid leukemia undergoing venetoclax-based therapy in two distinct cohorts. By querying the Study Alliance Leukemia database and the global health network TriNetX, we identified 138 and 717 patients respectively with an average age of 76 and 72 years who received venetoclax-based firstline therapy. When comparing patients who started treatment earlier or later than 10 days after initial diagnosis, no significant difference in median overall survival was observed - neither in the SAL cohort (7.7 vs. 9.6 months, p=.42) nor in the TriNetX cohort (7.5 vs. 7.2 months, p=.41). Similarly, severe infections, bleeding, and thromboembolic events were equally observed between early and later treatments, both in the overall patient groups and specific subgroups (age ≥75 years or leukocytes ≥20x109/L). This retrospective analysis indicates that delaying the start of venetoclax-based therapy in newly diagnosed acute myeloid leukemia might be a safe option for selected patients, provided that close clinical monitoring is performed.

Remission induction versus immediate allogeneic haematopoietic stem cell transplantation for patients with relapsed or poor responsive acute myeloid leukaemia (ASAP): a randomised, open-label, phase 3, non-inferiority trial.

BACKGROUND: Whether high-dose cytarabine-based salvage chemotherapy, administered to induce complete remission in patients with poor responsive or relapsed acute myeloid leukaemia scheduled for allogeneic haematopoietic stem-cell transplantation (HSCT) after intensive conditioning confers a survival advantage, is unclear. METHODS: To test salvage chemotherapy before allogeneic HSCT, patients aged between 18 and 75 years with non-favourable-risk acute myeloid leukaemia not in complete remission after first induction or untreated first relapse were randomly assigned 1:1 to remission induction with high-dose cytarabine (3 g/m2 intravenously, 1 g/m2 intravenously for patients >60 years or with a substantial comorbidity) twice daily on days 1-3 plus mitoxantrone (10 mg/m2 intravenously) on days 3-5 or immediate allogeneic HSCT for the disease control group. Block randomisation with variable block lengths was used and patients were stratified by age, acute myeloid leukaemia risk, and disease status. The study was open label. The primary endpoint was treatment success, defined as complete remission on day 56 after allogeneic HSCT, with the aim to show non-inferiority for disease control compared with remission induction with a non-inferiority-margin of 5% and one-sided type 1 error of 2·5%. The primary endpoint was analysed in both the intention-to-treat (ITT) population and in the per-protocol population. The trial is completed and was registered at ClinicalTrials.gov, NCT02461537. FINDINGS: 281 patients were enrolled between Sept 17, 2015, and Jan 12, 2022. Of 140 patients randomly assigned to disease control, 135 (96%) proceeded to allogeneic HSCT, 97 (69%) after watchful waiting only. Of 141 patients randomly assigned to remission induction, 134 (95%) received salvage chemotherapy and 128 (91%) patients subsequently proceeded to allogeneic HSCT. In the ITT population, treatment success was observed in 116 (83%) of 140 patients in the disease control group versus 112 (79%) of 141 patients with remission induction (test for non-inferiority, p=0·036). Among per-protocol treated patients, treatment success was observed in 116 (84%) of 138 patients with disease control versus 109 (81%) of 134 patients in the remission induction group (test for non-inferiority, p=0·047). The difference in treatment success between disease control and remission induction was estimated as 3·4% (95% CI -5·8 to 12·6) for the ITT population and 2·7% (-6·3 to 11·8) for the per-protocol population. Fewer patients with disease control compared with remission induction had non-haematological adverse events grade 3 or worse (30 [21%] of 140 patients vs 86 [61%] of 141 patients, χ2 test p<0·0001). Between randomisation and the start of conditioning, with disease control two patients died from progressive acute myeloid leukaemia and zero from treatment-related complications, and with remission induction two patients died from progressive acute myeloid leukaemia and two from treatment-related complications. Between randomisation and allogeneic HSCT, patients with disease control spent a median of 27 days less in hospital than those with remission induction, ie, the median time in hospital was 15 days (range 7-64) versus 42 days (27-121, U test p<0·0001), respectively. INTERPRETATION: Non-inferiority of disease control could not be shown at the 2·5% significance level. The rate of treatment success was also not statistically better for patients with remission induction. Watchful waiting and immediate transplantation could be an alternative for fit patients with poor response or relapsed acute myeloid leukaemia who have a stem cell donor available. More randomised controlled intention-to-transplant trials are needed to define the optimal treatment before transplantation for patients with active acute myeloid leukaemia. FUNDING: DKMS and the Gert and Susanna Mayer Stiftung Foundation.

Mimicking clinical trials with synthetic acute myeloid leukemia patients using generative artificial intelligence.

Clinical research relies on high-quality patient data, however, obtaining big data sets is costly and access to existing data is often hindered by privacy and regulatory concerns. Synthetic data generation holds the promise of effectively bypassing these boundaries allowing for simplified data accessibility and the prospect of synthetic control cohorts. We employed two different methodologies of generative artificial intelligence - CTAB-GAN+ and normalizing flows (NFlow) - to synthesize patient data derived from 1606 patients with acute myeloid leukemia, a heterogeneous hematological malignancy, that were treated within four multicenter clinical trials. Both generative models accurately captured distributions of demographic, laboratory, molecular and cytogenetic variables, as well as patient outcomes yielding high performance scores regarding fidelity and usability of both synthetic cohorts (n = 1606 each). Survival analysis demonstrated close resemblance of survival curves between original and synthetic cohorts. Inter-variable relationships were preserved in univariable outcome analysis enabling explorative analysis in our synthetic data. Additionally, training sample privacy is safeguarded mitigating possible patient re-identification, which we quantified using Hamming distances. We provide not only a proof-of-concept for synthetic data generation in multimodal clinical data for rare diseases, but also full public access to synthetic data sets to foster further research.

Long term results of a prospective multicenter observational study on the use of anti-human T-lymphocyte immunoglobulin (ATLG) in unrelated donor transplantation (ATOS study).

ATOS is a prospective observational study evaluating the outcome of patients receiving anti-human T-lymphocyte immunoglobulin (ATLG) in unrelated donor transplantation. Primary endpoint was severe GvHD and relapse-free survival (SGRFS). GvHD prophylaxis consisted of ATLG and CSA/ MTX or MMF. Outcome was compared to the ATLG arm of our prospective randomized phase III multicenter trial trial (RCT) [1, 2]. 165 patients, median age 54 (18; 77) years, with haematological malignancies with early (45.5%), intermediate (17.6%), and advanced (37.0%) disease were included. ATLG dose differed between centers according to local practise (median total ATLG dose of 46 (IQR 32-60, range 15-91) mg/kg). Median follow-up was 70 months. Estimated probabilities at 5 years follow up were for SGRFS 0.27, OS 0.52, DFS 0.43, NRM 0.23, relapse 0.34, acute GvhD °III/IV 0.13, severe chronic GvHD 0.27. OS rates differed dependent on disease status. An effect of the given ATLG dose could not be separated from potential center effects. Despite higher age and more advanced disease in ATOS, outcome was similar to the ATLG arm of our RCT. This long-term, multicenter, experience in routine clinical practice confirms the GvHD-protective effect of ATLG without compromising relapse and non-relapse mortality rates.Clinical Trial Registry: German clinical trials register DRKS00004581.

Long-term outcomes and renal responses following autologous hematopoietic stem cell transplantation for light chain deposition disease: a retrospective study on behalf of the Chronic Malignancies Working Party of the European Society for Blood and Marrow Transplantation.

There is little long-term outcome data on the efficacy of autologous hematopoietic stem cell transplantation (ASCT) in light chain deposition disease (LCDD). We identified 51 LCDD patients in the EBMT registry who had undergone upfront ASCT between 1995 and 2021. The median serum creatinine was 280 µmol/L and 45% required renal replacement therapy (RRT) at time of transplant. The melphalan dose was 100mg/m2 in 23%, 140mg/m2 in 55% and 200 mg/m2 in 21%. The rate of very good partial response or better improved from 41% pre-transplant to 66% at Day +100 post-ASCT. In RRT-independent patients, there was a modest improvement in renal function within the first 3 months; the median eGFR increased from 44 to 51 ml/min/1.73 m2. There was no further change between 3 and 12 months post- ASCT. No patient who was RRT-independent at ASCT became RRT dependent by Day + 100 post-ASCT. Median follow-up post-ASCT was 84 months (IQR: 46-122). At 6-years post ASCT, overall survival (OS) was 88% (95% CI: 78-98%) and PFS was 44% (95% CI: 28-60%). The 2-year cumulative incidence of relapse and non-relapse mortality (NRM) was 17% (95% CI: 6-27%) and 2% (95% CI: 0-6%), respectively. The cumulative incidence of renal transplantation at 4 years after ASCT was 27% (95% CI 13-41) with renal transplantation performed between 6.3 and 52.9 months post-ASCT (median 24.7 months). ASCT represents a feasible option for LCDD patients even if RRT dependent at time of transplant. Outcomes are favourable with low NRM and good long-term OS.

Loss of maternal calcitriol reversibly alters early offspring growth and skeletal development in mice.

Ablation of Cyp27b1 eliminates calcitriol but does not disturb fetal mineral homeostasis or skeletal development. However, independent of fetal genotypes, maternal loss of Cyp27b1 altered fetal mineral and hormonal levels compared to offspring of WT dams. We hypothesized that these maternal influences would alter postnatal skeletal development. Cyp27b1 null and WT females were mated to bear only Cyp27b1+/- offspring. 48 hrs after birth, pups were cross-fostered to dams of the same or opposite genotype that bore them. Maternal and offspring samples were collected on days 21 (weaning) and 42. Offspring measurements included minerals and hormones, bone mineral content (BMC) by DXA, ash weight and mineral content, gene expression, 3-point bending tests, and microCT. Maternal lactational behavior was evaluated. Milk was analyzed for nutritional content. At day 21, offspring fostered by nulls, independent of birth dam, had ~20% lower weight, BMC, ash weight, and ash calcium than pups fostered by WT dams. Adjustment for body weight accounted for the lower BMC but not the lower ash weight and ash calcium. Hormones and serum/urine minerals did not differ across offspring groups. Offspring fostered by nulls had shorter femurs and lower cortical thickness, mean polar moment of inertia, cortical area, trabecular bone volume, and trabecular number. Dam lactational behaviors and milk nutritional content did not differ between groups. At day 42, body weight, ash weight, lengths, BMC, and tibial bone strength were no longer different between pups fostered by null vs. WT dams. In summary, pups fostered by Cyp27b1 nulls, regardless of birth dam, have proportionately smaller skeletons at 21 days, impaired microstructure, but normal mineral homeostasis. The skeletal effects are largely recovered by day 42 (three weeks after weaning). In conclusion, maternal loss of calcitriol impairs early postnatal cortical bone growth and trabecular bone mass, but affected offspring catch up after weaning.

Randomized phase III GnG study on two schedules of gemtuzumab ozogamicin as adjunct to intensive induction therapy and double-blinded intensive post-remission therapy with or without glasdegib in patients with newly diagnosed acute myeloid leukemia.

Not available.

Impact of post-transplant cyclophosphamide (PTCy)-based prophylaxis in matched sibling donor allogeneic haematopoietic cell transplantation for patients with myelodysplastic syndrome: a retrospective study on behalf of the Chronic Malignancies Working Party of the EBMT.

We retrospectively compared outcomes of 404 MDS patients undergoing 1st matched sibling donor allo-HCT receiving either PTCy-based (n = 66) or other "conventional prophylaxis" (n = 338; mostly calcineurin inhibitor + methotrexate or MMF). Baseline characteristics were balanced, except for higher use of myeloablative regimens in the PTCy group (52.3% vs. 38.2%, p = 0.047). Incidences of neutrophil (Day +28: 89% vs. 97%, p = 0.011) and platelet (Day +100: 89% vs. 97%, p < 0.001) engraftment were lower for PTCy-based. Day +100 cumulative incidences of grade II-IV and III-IV aGVHD, and 5-year CI of extensive cGVHD were 32%, 18% and 18% for PTCy-based and 25% (p = 0.3), 13% (p = 0.4) and 31% (p = 0.09) for the conventional cohort. Five-year OS (51% vs. 52%, p = 0.6) and GRFS (33% vs. 25%, p = 0.6) were similar between groups. Patients receiving PTCy had a trend to a lower cumulative incidence of relapse (20% vs. 33%, p = 0.06), not confirmed on multivariable analysis (p = 0.3). Although higher NRM rates were observed in patients receiving PTCy (32% vs. 21%, p = 0.02) on univariate analysis, this was not confirmed on multivariate analysis (HR 1.46, p = 0.18), and there was no resultant effect on OS (HR 1.20, p = 0.5). Based on these data, PTCy prophylaxis appears to be an attractive option for patients with MDS undergoing MSD allo-HCT.

Autologous hematopoietic cell transplantation for T-cell prolymphocytic leukemia: a retrospective study on behalf of the Chronic Malignancies Working Party of the EBMT.

Not available.

Epimeric vitamin D and cardiovascular structure and function in advanced CKD and after kidney transplantation.

BACKGROUND: 25-hydroxyvitamin D can undergo C-3 epimerization to produce 3-epi-25(OH)D3. 3-epi-25(OH)D3 levels decline in chronic kidney disease (CKD), but its role in regulating the cardiovascular system is unknown. Herein, we examined the relationship between 3-epi-25(OH)D3, and cardiovascular functional and structural endpoints in patients with CKD. METHODS: We examined n = 165 patients with advanced CKD from the Cardiopulmonary Exercise Testing in Renal Failure and After Kidney Transplantation (CAPER) study cohort, including those who underwent kidney transplant (KTR, n = 76) and waitlisted patients who did not (NTWC, n = 89). All patients underwent cardiopulmonary exercise testing and echocardiography at baseline, 2 months and 12 months. Serum 3-epi-25(OH)D3 was analyzed by liquid chromatography-tandem mass spectrometry. RESULTS: Patients were stratified into quartiles of baseline 3-epi-25(OH)D3 (Q1: <0.4 ng/mL, n = 51; Q2: 0.4 ng/mL, n = 26; Q3: 0.5-0.7 ng/mL, n = 47; Q4: ≥0.8 ng/mL, n = 41). Patients in Q1 exhibited lower peak oxygen uptake [VO2Peak = 18.4 (16.2-20.8) mL/min/kg] compared with Q4 [20.8 (18.6-23.2) mL/min/kg; P = .009]. Linear mixed regression model showed that 3-epi-25(OH)D3 levels increased in KTR [from 0.47 (0.30) ng/mL to 0.90 (0.45) ng/mL] and declined in NTWC [from 0.61 (0.32) ng/mL to 0.45 (0.29) ng/mL; P < .001]. Serum 3-epi-25(OH)D3 was associated with VO2Peak longitudinally in both groups [KTR: ß (standard error) = 2.53 (0.56), P < .001; NTWC: 2.73 (0.70), P < .001], but was not with left ventricular mass or arterial stiffness. Non-epimeric 25(OH)D3, 24,25(OH)2D3 and the 25(OH)D3:24,25(OH)2D3 ratio were not associated with any cardiovascular outcome (all P > .05). CONCLUSIONS: Changes in 3-epi-25(OH)D3 levels may regulate cardiovascular functional capacity in patients with advanced CKD.

New Twist on the Light-Switch Effect: Controlling the Fate of Excited States with pH in a 4-Hydroxy-thiazol-extended Ruthenium(II) Dppz Complex.

We present a pH-dependent study of the excited state dynamics of a novel Ru complex bearing a 4-hydroxy thiazol-substituted dppz (dipyridophenazine) ligand (RuTzOH) and its deprotonated form (RuTzO-). We combine steady-state and time-resolved absorption and emission spectroscopy with electrochemical investigations to characterize the excited state relaxation, which upon photoexcitation at 400 nm is determined by a multitude of initially populated MLCT states for both complexes. Subsequently, for RuTzOH, two long-lived excited states are populated, leading to dual emission from the complexes, a feature that vanishes upon deprotonation. Upon deprotonation, the electron density on the dppz moiety increases significantly, leading to rapid energy populating ligand-centered states and thus deactivating the initially excited MLCT states.

Norton-Beer apodization and its Fourier transform.

In Fourier transform spectroscopy, apodization is used to alter the instrument line shape, reducing the prominence of its side lobes. The Fourier transform of the apodization window is of great interest as it allows us to compute or optimize the line shape. In the last decades, many apodization windows have been proposed, from which the group of Norton-Beer apodization functions gained large popularity in Fourier transform spectroscopy. While for a small set of specific Norton-Beer apodization functions analytical solutions of the Fourier transform have been presented in the past, we present here a general method, which allows us to calculate the analytical solution of the Fourier transform for any Norton-Beer apodization function. This paper also documents the free Python library called norton_beer. It contains functions to generate apodization windows and their Fourier transform following the presented analytical solution. Furthermore, new Norton-Beer apodization functions can be generated for any desired spectral resolution.

Autologous-allogeneic versus autologous tandem stem cell transplantation and maintenance therapy with thalidomide for multiple myeloma patients less than 60 years of age: a prospective phase II study

The role of autologous-allogeneic tandem stem cell transplantation (alloTSCT) followed by maintenance as upfront treatment for multiple myeloma (MM) is controversial. Between 2008 and 2014 a total of 217 MM patients with a median age of 51 years were included by 20 German centers within an open-label, parallel-group, multi-center clinical trial to compare alloTSCT to auto tandem transplantation TSCT (autoTSCT) followed by a 2-year maintenance therapy with thalidomide (100 mg/d) in both arms with respect to relapse/progression-free survival (PFS) and other relevant outcomes. A total of 178 patients underwent second SCT (allo n = 132 and auto n = 46). PFS at 4 years after the second SCT was 47% (CI: 38-55%) for alloTSCT and 35% (CI: 21-49%) for autoTSCT (p = 0.26). This difference increased to 22% at 8 years (p = 0.10). The cumulative incidences of non-relapse mortality (NRM) and of relapse at 4 years were 13% (CI: 8-20%) and 2% (CI: 0.3-2%) (p = 0.044) and 40% (CI: 33-50%) and 63% (CI: 50-79%) for alloTSCT and autoTSCT (p = 0.04), respectively. The difference for relapse/progression increased to 33% (alloTSCT: 44%, autoTSCT: 77%) at a median follow-up of 82 months (p = 0.002). Four-year OS was 66% (CI: 57-73%) for alloTSCT and 66% (CI: 50-78%) for auto TSCT (p = 0.91) and 8-year OS was 52% and 50% (p = 0.87), respectively. AlloTSCT followed by thalidomide maintenance reduced the rate of recurrence or progression during a follow-up period of up to 10 years but failed to improve PFS significantly.

Mutated IKZF1 is an independent marker of adverse risk in acute myeloid leukemia.

Genetic lesions of IKZF1 are frequent events and well-established markers of adverse risk in acute lymphoblastic leukemia. However, their function in the pathophysiology and impact on patient outcome in acute myeloid leukemia (AML) remains elusive. In a multicenter cohort of 1606 newly diagnosed and intensively treated adult AML patients, we found IKZF1 alterations in 45 cases with a mutational hotspot at N159S. AML with mutated IKZF1 was associated with alterations in RUNX1, GATA2, KRAS, KIT, SF3B1, and ETV6, while alterations of NPM1, TET2, FLT3-ITD, and normal karyotypes were less frequent. The clinical phenotype of IKZF1-mutated AML was dominated by anemia and thrombocytopenia. In both univariable and multivariable analyses adjusting for age, de novo and secondary AML, and ELN2022 risk categories, we found mutated IKZF1 to be an independent marker of adverse risk regarding complete remission rate, event-free, relapse-free, and overall survival. The deleterious effects of mutated IKZF1 also prevailed in patients who underwent allogeneic hematopoietic stem cell transplantation (n = 519) in both univariable and multivariable models. These dismal outcomes are only partially explained by the hotspot mutation N159S. Our findings suggest a role for IKZF1 mutation status in AML risk modeling.

A phase II dose evaluation pilot feasibility randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study).

BACKGROUND: Vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (ICU) and associated with worse clinical course. Trials in adult ICU demonstrate rapid restoration of vitamin D status using an enteral loading dose is safe and may improve outcomes. There have been no published trials of rapid normalization of VDD in the pediatric ICU. METHODS: We conducted a multicenter placebo-controlled phase II pilot feasibility randomized clinical trial from 2016 to 2017. We randomized 67 critically ill children with VDD from ICUs in Canada, Chile and Austria using a 2:1 randomization ratio to receive a loading dose of enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or placebo. Participants, care givers, and outcomes assessors were blinded. The primary objective was to determine whether the loading dose normalized vitamin D status (25(OH)D > 75 nmol/L). Secondary objectives were to evaluate for adverse events and assess the feasibility of a phase III trial. RESULTS: Of 67 randomized participants, one was withdrawn and seven received more than one dose of cholecalciferol before the protocol was amended to a single loading dose, leaving 59 participants in the primary analyses (40 treatment, 19 placebo). Thirty-one/38 (81.6%) participants in the treatment arm achieved a plasma 25(OH)D concentration > 75 nmol/L versus 1/18 (5.6%) the placebo arm. The mean 25(OH)D concentration in the treatment arm was 125.9 nmol/L (SD 63.4). There was no evidence of vitamin D toxicity and no major drug or safety protocol violations. The accrual rate was 3.4 patients/month, supporting feasibility of a larger trial. A day 7 blood sample was collected for 84% of patients. A survey administered to 40 participating families showed that health-related quality of life (HRQL) was the most important outcome for families for the main trial (30, 75%). CONCLUSIONS: A single 10,000 IU/kg dose can rapidly and safely normalize plasma 25(OH)D concentrations in critically ill children with VDD, but with significant variability in 25(OH)D concentrations. We established that a phase III multicentre trial is feasible. Using an outcome collected after hospital discharge (HRQL) will require strategies to minimize loss-to-follow-up. CLINICALTRIALS: gov NCT02452762 Registered 25/05/2015.