Sinusoidal obstruction syndrome, also known as veno-occlusive disease (SOS/VOD), is a potentially life threatening complication that can develop after hematopoietic cell transplantation. Although SOS/VOD progressively resolves within a few weeks in most patients, the most severe forms result in multi-organ dysfunction and are associated with a high mortality rate (>80%). Therefore, careful attention must be paid to allow an early detection of SOS/VOD, particularly as drugs have now proven to be effective and licensed for its treatment. Unfortunately, current criteria lack sensitivity and specificity, making early identification and severity assessment of SOS/VOD difficult. The aim of this work is to propose a new definition for diagnosis, and a severity-grading system for SOS/VOD in adult patients, on behalf of the European Society for Blood and Marrow Transplantation.

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate >80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.

Background Patients with hematological malignancies (HM) are at high risk of mortality from SARS-CoV-2 disease 2019 (COVID-19). A better understanding of risk factors for adverse outcomes may improve clinical management in these patients. We therefore studied baseline characteristics of HM patients developing COVID-19 and analyzed predictors of mortality. Methods The survey was supported by the Scientific Working Group Infection in Hematology of the European Hematology Association (EHA). Eligible for the analysis were adult patients with HM and laboratory-confirmed COVID-19 observed between March and December 2020. Results The study sample includes 3801 cases, represented by lymphoproliferative (mainly non-Hodgkin lymphoma n = 1084, myeloma n = 684 and chronic lymphoid leukemia n = 474) and myeloproliferative malignancies (mainly acute myeloid leukemia n = 497 and myelodysplastic syndromes n = 279). Severe/critical COVID-19 was observed in 63.8% of patients (n = 2425). Overall, 2778 (73.1%) of the patients were hospitalized, 689 (18.1%) of whom were admitted to intensive care units (ICUs). Overall, 1185 patients (31.2%) died. The primary cause of death was COVID-19 in 688 patients (58.1%), HM in 173 patients (14.6%), and a combination of both COVID-19 and progressing HM in 155 patients (13.1%). Highest mortality was observed in acute myeloid leukemia (199/497, 40%) and myelodysplastic syndromes (118/279, 42.3%). The mortality rate significantly decreased between the first COVID-19 wave (March–May 2020) and the second wave (October–December 2020) (581/1427, 40.7% vs. 439/1773, 24.8%, p value < 0.0001). In the multivariable analysis, age, active malignancy, chronic cardiac disease, liver disease, renal impairment, smoking history, and ICU stay correlated with mortality. Acute myeloid leukemia was a higher mortality risk than lymphoproliferative diseases. Conclusions This survey confirms that COVID-19 patients with HM are at high risk of lethal complications. However, improved COVID-19 prevention has reduced mortality despite an increase in the number of reported cases.

Summary of Key Recommendations Diagnosis It is recommended that the diagnosis of veno‐occlusive disease (sinusoidal obstruction syndrome) [VOD (SOS)] be based primarily on established clinical criteria (modified Seattle or Baltimore criteria) (1A). Ultrasound imaging may be helpful in the exclusion of other disorders in patients with suspected VOD (SOS) (1C). It is recommended that liver biopsy be reserved for patients in whom the diagnosis of VOD (SOS) is unclear and there is a need to exclude other diagnoses (1C). It is recommended that liver biopsies are undertaken using the transjugular approach in order to reduce the risks associated with the procedure (1C). It is suggested that the role of plasminogen activator inhibitor 1 levels remains an area for further research but that these levels should not form part of the routine diagnostic work‐up for VOD (SOS) at present (2C). Risk factors It is recommended that patients are assessed for risk factors for VOD (SOS) and that these risk factors are addressed prior to haematopoietic stem cell transplantation (1A). Prophylaxis Defibrotide is recommended at a dose of 6·25 mg/kg intravenously four times daily for the prevention of VOD (SOS) in children undergoing allogeneic stem cell transplantation with the following risk factors: pre‐existing hepatic disease, second myeloablative transplant, allogeneic transplant for leukaemia beyond second relapse, conditioning with busulfan‐containing regimens, prior treatment with gemtuzumab ozogamicin, diagnosis of primary haemophagocytic lymphohistiocytosis, adrenoleucodystrophy or osteopetrosis (1A). Defibrotide is suggested at a dose of 6·25 mg/kg intravenously four times daily for the prevention of VOD (SOS) in adults undergoing allogeneic stem cell transplantation with the following risk factors: pre‐existing hepatic disease, second myeloablative transplant, allogeneic transplant for leukaemia beyond second relapse, conditioning with busulfan‐containing regimens, prior treatment with gemtuzumab ozogamicin, diagnosis of primary haemophagocytic lymphohistiocytosis, adrenoleucodystrophy or osteopetrosis (2B). Prostaglandin E1 is not recommended in the prophylaxis of VOD (SOS) due to lack of efficacy and toxicity (1B). Pentoxifylline is not recommended in the prophylaxis of VOD (SOS) due to lack of efficacy (1A). Ursodeoxycholic acid is suggested for use in the prophylaxis of VOD (SOS) (2C). Heparin (unfractionated and low molecular weight) is not suggested for use in the prophylaxis of VOD (SOS) due to the risk of increased toxicity (2B). Antithrombin is not suggested for the prophylaxis of VOD (SOS) due to lack of efficacy (2B). Treatment Defibrotide is recommended in the treatment of VOD (SOS) in adults and children (1B). Tissue plasminogen activator is not recommended for use in the treatment of VOD (SOS) due to the associated risk of haemorrhage (1B). N‐acetylcysteine is not routinely recommended for use in the treatment of veno‐occlusive disease due to lack of efficacy (1A). Methylprednisolone may be consider...

Summary Antifungal prophylaxis for allogeneic haematopoietic stem‐cell transplant (alloHCT) recipients should prevent invasive mould and yeast infections (IFIs) and be well tolerated. This prospective, randomized, open‐label, multicentre study compared the efficacy and safety of voriconazole (234 patients) versus itraconazole (255 patients) in alloHCT recipients. The primary composite endpoint, success of prophylaxis, incorporated ability to tolerate study drug for ≥100 d (with ≤14 d interruption) with survival to day 180 without proven/probable IFI. Success of prophylaxis was significantly higher with voriconazole than itraconazole (48·7% vs. 33·2%, P < 0·01); more voriconazole patients tolerated prophylaxis for 100 d (53·6% vs. 39·0%, P < 0·01; median total duration 96 vs. 68 d). The most common (>10%) treatment‐related adverse events were vomiting (16·6%), nausea (15·8%) and diarrhoea (10·4%) for itraconazole, and hepatotoxicity/liver function abnormality (12·9%) for voriconazole. More itraconazole patients received other systemic antifungals (41·9% vs. 29·9%, P < 0·01). There was no difference in incidence of proven/probable IFI (1·3% vs. 2·1%) or survival to day 180 (81·9% vs. 80·9%) for voriconazole and itraconazole respectively. Voriconazole was superior to itraconazole as antifungal prophylaxis after alloHCT, based on differences in the primary composite endpoint. Voriconazole could be given for significantly longer durations, with less need for other systemic antifungals.