Key Points• Defibrotide improves day 1100 survival and CR in patients with VOD and MOF compared with a historical control.• The historical control selection methodology offers a novel approach for investigation of a life-threatening orphan disease.Hepatic veno-occlusive disease (VOD), also called sinusoidal obstruction syndrome (SOS), is a potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). Untreated hepatic VOD/SOS with multi-organ failure (MOF) is associated with >80% mortality. Defibrotide has shown promising efficacy treating hepatic VOD/SOS with MOF in phase 2 studies. This phase 3 study investigated safety and efficacy of defibrotide in patients with established hepatic VOD/SOS and advanced MOF. Patients (n 5 102) given defibrotide 25 mg/kg per day were compared with 32 historical controls identified out of 6867 medical charts of HSCT patients by blinded independent reviewers. Baseline characteristics between groups were well balanced. The primary endpoint was survival at day 1100 post-HSCT; observed rates equaled 38.2% in the defibrotide group and 25% in the controls (23% estimated difference; 95.1% confidence interval [CI], 5.2-40.8; P 5 .0109, using a propensityadjusted analysis). Observed day 1100 complete response (CR) rates equaled 25.5% for defibrotide and 12.5% for controls (19% difference using similar methodology; 95.1% CI, 3.5-34.6; P 5 .0160). Defibrotide was generally well tolerated with manageable toxicity. Related adverse events (AEs) included hemorrhage or hypotension; incidence of common hemorrhagic AEs (including pulmonary alveolar [11.8% and 15.6%] and gastrointestinal bleeding [7.8% and 9.4%]) was similar between the defibrotide and control groups, respectively. Defibrotide was associated with significant improvement in day 1100 survival and CR rate. The historical-control methodology offers a novel, meaningful approach for phase 3 evaluation of orphan diseases associated with high mortality. This trial was registered at www.clinicaltrials.gov as

Importance Variability in prescribed 6-mercaptopurine and lack of adherence to 6-mercaptopurine could result in intra-individual variability in systemic exposure to 6-mercaptopurine (measured as erythrocyte thioguanine nucleotide levels) in children with acute lymphoblastic leukemia. The impact of intra-individual variability in systemic exposure to 6-mercaptopurine on relapse risk is unknown. Objective To determine impact of high intra-individual variability in 6-mercaptopurine systemic exposure on relapse risk in children with acute lymphoblastic leukemia. Design Prospective longitudinal design; daily adherence monitoring, 6-mercaptopurine dose-intensity and erythrocyte thioguanine nucleotide levels (pmol/8*10^8 erythrocytes) measured for 6 consecutive months per patient; cohort followed for a median of 6.7 years from diagnosis. Setting Children’s Oncology Group study (COG-AALL03N1); 94 participating institutions; ambulatory care setting. Participants Participants included 742 children meeting the following eligibility criteria: diagnosis of acute lymphoblastic leukemia at ≤21 years; in first continuous remission at study entry; receiving self/parent/caregiver-administered oral 6-mercaptopurine during maintenance. Median age at diagnosis: 5 years; 68% were male; 43% with NCI-based high-risk disease. Main Outcome Measures Adherence measured electronically using Medication Event Monitoring System that recorded date/time of each 6-mercaptopurine bottle opening; adherence rate defined as ratio of days of 6-mercaptopurine bottle opened to days when 6-mercaptopurine prescribed. 6-mercaptopurine doses actually prescribed were divided by planned protocol doses (75mg/m2/day) to compute average monthly dose-intensity. Electronically-monitored adherence (68,716 person-days), 6-mercaptopurine dose-intensity (120,439 person-days) and monthly erythrocyte thioguanine nucleotide levels (n=3,944 measurements) contributed to the analysis. Using intra-individual coefficients of variation (CV %), patients were classified as having stable (CV % <85th percentile) vs. varying (CV % ≥85th percentile) indices. Results Adjusting for clinical prognosticators, patients with 6-mercaptopurine non-adherence (mean adherence rate <95%) were at a 2.7 fold increased risk of relapse (95% confidence interval [CI], 1.3 to 5.6, p=0.01). Among adherers, high intra-individual variability in thioguanine nucleotide levels contributes to increased relapse risk (HR=4.4, 95% CI, 1.2 to 15.7, p=0.02). Furthermore, adherers with varying thioguanine nucleotide levels had varying 6-mercaptopurine dose-intensity (OR=4.5, p=0.006) and 6-mercaptopurine drug interruptions (OR=10.2, p=0.003). Conclusions and Relevance These findings emphasize the need to maximize 6-mercaptopurine adherence and maintain steady thiopurine exposure to minimize relapse in children with acute lymphoblastic leukemia.

Background Treatment cures over 90% of children with Wilms tumor (WT) who subsequently risk late morbidity and mortality. This study describes the 25-year outcomes of 5-year Wilms tumor survivors in the Childhood Cancer Survivor Study (CCSS). Procedure The CCSS, a multi-institutional retrospective cohort study, assessed Wilms tumor survivors (n=1256), diagnosed 1970 – 1986, for chronic health conditions, health status, health care utilization, socioeconomic status, subsequent malignant neoplasms (SMNs), and mortality compared to the US population and a sibling cohort (n=4023). Results The cumulative incidence of all and severe chronic health conditions was 65.4% and 24.2% at 25 years. Hazard Ratios [HR] were 2.0, 95% Confidence Interval [CI], 1.8-2.3 for grades 1 -4 and 4.7, 95% CI, 3.6-6.1 for grade 3-4, compared to sibling group. WT survivors reported more adverse general health status than the sibling group (Prevalence Ratio [PR] 1.7; 95% CI, 1.2–2.4), but mental health status, socioeconomic outcome, and health care utilization were similar. The cumulative incidence of SMN was 3.0% (95%CI, 1.9–4.0%) and of mortality was 6.1% (95%CI, 4.7-7.4%). Radiation exposure increased the likelihood of congestive heart failure (CHF) (no doxorubicin - HR 6.6; 95%CI, 1.6-28.3; doxorubicin ≤ 250 mg/m2 - HR 13.0; 95%CI, 1.9-89.7; doxorubicin > 250 mg/m2 - HR 18.3; 95%CI, 3.8-88.2), SMN (Standardized Incidence Ratio [SIR] 9.0; 95%CI, 3.9-17.7 with and 4.9; 95%CI, 1.8-10.6 without doxorubicin) and death. Conclusion Long-term survivors of WT treated from 1970 to 1986 are at increased risk of treatment related morbidity and mortality 25 years from diagnosis.