Incidence, Predictors, and Outcomes of Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome after Reduced-Intensity Allogeneic Hematopoietic Cell Transplantation

Fludarabine Melphalan, Reduced-dose Busulfan Versus Fludarabine, Melphalan, Full-dose Busulfan in Patients Receiving Cord Blood Transplantation

BACKGROUND

Various reduced-intensity conditioning/reduced-toxicity conditioning regimens have been developed for patients receiving allogeneic hematopoietic cell transplantation. The balance between disease relapse and toxicity can be partly dependent on reduced-intensity conditioning/reduced-toxicity conditioning regimens. This retrospective study aimed to compare the nonrelapse mortality, relapse incidence, progression-free survival, and overall survival rates between the fludarabine/melphalan/reduced-dose busulfan (Flu/Mel/Bu2; busulfan at a dose of 6.4 mg/kg intravenously) and fludarabine/melphalan/full-dose busulfan (Flu/Mel/Bu4; busulfan at a dose of 12.8 mg/kg intravenously) regimens in patients receiving umbilical cord blood transplantation.

METHOD

Eighty-seven adult patients who received the Flu/Mel/Bu2 (n = 45) or Flu/Mel/Bu4 (n = 42) regimen as a conditioning regimen before umbilical cord blood transplantation at our institution between January 2013 and December 2022 were included in this study.

RESULTS

There were no significant differences in terms of clinical outcomes including nonrelapse mortality, relapse incidence, progression-free survival, and overall survival rates between the two regimens. Further, even in higher-risk patients classified according to the Refined Disease Risk Index, the Flu/Mel/Bu2 regimen was comparable to the Flu/Mel/Bu4 regimen.

CONCLUSION

The novel Flu/Mel/Bu2 regimen could be applied in clinical settings as it can be tolerated and effective in older patients.

Rationale for Hepatitis C Virus Treatment During Hematopoietic Stem Cell Transplant in the Era of Novel Direct-Acting Antivirals

BACKGROUND AND AIMS

Untreated hepatitis C (HCV) infection in patients undergoing hematopoietic stem cell transplantation (HSCT) can lead to worse outcomes. Traditionally, HSCT patients infected with HCV would wait until after immune reconstitution to receive HCV therapy, as the oncologic urgency of transplant would not allow time for a full preceding treatment course of HCV therapy. However, in the era of newer direct-acting antivirals (DAAs), we propose that concomitant treatment of HCV while undergoing HSCT is safe and feasible, while keeping in mind potential drug-drug interactions.

METHODS

A literature review was performed to summarize the available data on the impact of HCV on patients undergoing HSCT. Drug-drug interactions for DAA's and pertinent HSCT drugs were evaluated using Lexicomp online® and http://hep-druginteractions.org .

RESULTS

During HSCT, HCV appears to be a conditional risk factor for sinusoidal obstruction syndrome and a potential risk factor for graft versus host disease, both of which are associated with increased mortality. HCV reactivation and exacerbation may impact the use of chemotherapeutics, but available studies haven't shown impact specifically on HSCT. Limited case reports exist but demonstrate safe and effective use DAAs during HSCT. These, along with a drug-drug interaction review demonstrate agents such as sofosbuvir/velpatasvir and glecaprevir/pibrentasvir are promising DAAs for use in HSCT.

CONCLUSION

HCV infection may worsen outcomes for patients undergoing HSCT. Concomitant treatment of HCV during HSCT using newer DAAs appears feasible and may improve patient morbidity and mortality, however large-scale studies are needed to further support this practice.

Hepatic Veno-Occlusive Disease and Colorectal Cancer: Expect the Unexpected

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a rare liver vascular condition, potentially life-threatening, with clinical signs of portal hypertension, frequently reported in relation to bone marrow transplantation and possibly in non-transplantation-related chemotherapy. We report the case of a 65-year-old female patient who insidiously developed fatigue, mild tenderness of the right upper abdominal quadrant, hepato-splenomegaly and slight weight gain consecutive to ascites development, as well as persistent elevation of transaminases and mild thrombocytopenia. To note, she had a previous history of colorectal cancer (CRC) with liver metastases and several courses of chemotherapy. Abdominal duplex and elastography measurements made the diagnosis of cirrhosis improbable. A lot of lab work-ups were performed in order to rule out several diseases and conditions. Further, transjugular access was used to perform the measurement of the hepatic venous pressure gradient and liver biopsy that confirmed SOS/VOD. In late 2023, she was diagnosed with endometrial adenocarcinoma, requiring chemotherapy again. At present, the liver condition is stationary, but the prognosis is, however, uncertain. In conclusion, we presented the atypical case of a female patient who developed portal hypertension syndrome associated with the late onset of SOS/VOD, after 5-fluorouracil and oxaliplatin chemotherapy for CRC and liver metastases, subsequently diagnosed with endometrial adenocarcinoma, which posed many diagnostic and therapeutic challenges. Given the potentially bad outcome, an early diagnosis of SOS/VOD in patients receiving drugs of risk is important not only to stratify further risk, but also to initiate an appropriate therapy in order to improve the prognosis.

Incidence, Etiology and Prognosis of Initial Liver Injury After Allogeneic Hematopoietic Stem Cell Transplantation: A Multi-Center Retrospective Study

BACKGROUND

Liver injury post allogeneic hematopoietic stem cell transplantation (Allo-HSCT), particularly first-time occurrences, is a prevalent and severe complication.

METHODS

Clinical data from 262 patients treated at 3 medical centers in Shenzhen, China, between January 2018 and December 2021 were retrospectively collected. Risk factors and outcomes of initial liver injury post allo-HSCT were analyzed.

RESULTS

Liver injury occurred in 70.8% of patients, with drug-induced liver injury (DILI) being the most common cause. Other causes included graft-versus-host disease (GVHD) and veno-occlusive disease (VOD). Pre-transplant HBsAg positivity was a significant risk factor. Differences in the timing and survival outcomes were observed among patients with different causes and types of liver injury. Patients with VOD or hepatic aGVHD had lower overall survival compared to those with DILI or hepatic cGVHD. Patients with isolated enzyme elevation had a more favorable prognosis than those with isolated bilirubin elevation or simultaneous enzyme and bilirubin elevation.

CONCLUSION

Findings of our study serve as a crucial resource for clinicians, assisting in the challenging task of diagnosing and managing liver injuries after allo-HSCT, especially when it occurs for the first time, which may ultimately help to reduce early treatment-related mortality and enhance the long-term survival of transplant recipients.

Prevention and management of acute toxicities from conditioning regimens during hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) remains the only curative option for several hematological malignancies. Its use has continued to grow, with an estimated 23,500 transplants performed annually in the United States alone. The acute toxicities that occur from conditioning chemotherapy can impact the peri-transplant period and have substantial implications on patients' tolerability and outcomes, irrespective of the treatment of their disease. Chemotherapy-induced nausea vomiting (CINV), mucositis, transplant-associated thrombotic microangiopathy (TA-TMA), and sinusoidal obstruction syndrome, also known as a veno-occlusive disease (SOS/VOD) can all have significant implications for patients. These acute complications begin with the start of conditioning chemotherapy and add to potential toxicity for patients throughout the early post-transplant period, from Day +30 for CINV, mucositis, and SOS, and which can continue through at least Day +100 with the onset of TA-TMA. These toxicities must be prevented and managed appropriately. This review will summarize the literature surrounding them and guide their management.

Diagnosis and management of endothelial disorders following haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation is a mainstay of therapy for numerous malignant and nonmalignant diseases. Endothelial activation and dysfunction occur after stem cell transplantation, driven by various patient- and transplant-specific factors. This can manifest as one of the relatively uncommon endothelial injury syndromes, such as sinusoidal obstruction syndrome, transplant-associated thrombotic microangiopathy, idiopathic pneumonia syndrome, capillary leak syndrome, engraftment syndrome or posterior reversible encephalopathy syndrome. This review focuses on the pathogenesis, classification and diagnosis of these disorders, as well as provides guidance on risk mitigation and treatment.

Liver Pathology After Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is used to treat a variety of hematologic malignancies and autoimmune conditions. The immunosuppressive medications as well as other therapies used both before and after transplantation leave patients susceptible to a wide spectrum of complications, including liver injury. Causes for liver damage associated with stem cell transplantation include sinusoidal obstruction syndrome, graft-versus-host disease, iron overload, and opportunistic infection. Here, the authors review the clinical and pathological findings of these etiologies of liver injury and provide a framework for diagnosis.

Real-world use of defibrotide for veno-occlusive disease/sinusoidal obstruction syndrome: the DEFIFrance Registry Study

Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of haematopoietic cell transplantation (HCT) conditioning. The DEFIFrance post-marketing registry study evaluated effectiveness and safety in patients who received defibrotide. It collected retrospective/prospective patient data from 53 French HCT centres from July 2014 to March 2020. Primary endpoints were survival and complete response (CR; total serum bilirubin <2 mg/dL, multiorgan failure resolution) at Day 100 post-HCT among patients with severe/very severe VOD/SOS. A secondary endpoint was evaluation of treatment-emergent serious adverse events (TESAEs) of interest. Of 798 patients analysed, 251 and 81 received defibrotide treatment for severe/very severe VOD/SOS and mild/moderate VOD/SOS post-HCT, respectively; 381 received defibrotide for VOD/SOS prophylaxis. In patients with severe/very severe VOD/SOS post-HCT, Kaplan-Meier-estimated CR at Day 100 was 74% (95% confidence interval [CI]: 66%, 81%). At Day 100, 137/251 (55%) were alive and in CR. Kaplan-Meier-estimated Day 100 post-HCT survival was 61% (95% CI: 55%, 67%) in patients with severe/very severe VOD/SOS. TESAEs of interest occurred in 29% of these patients; VOD/SOS-related mortality at 12 months was 15%. DEFIFrance represents the largest collection of real-world data on post-registration defibrotide use, supporting the real-world utility of defibrotide for patients with severe/very severe VOD/SOS post-HCT.

Low Incidence of hepatic sinusoidal obstruction syndrome/veno-occlusive disease in adults undergoing allogenic stem cell transplantation with prophylactic ursodiol and low-dose heparin

Hepatic sinusoidal obstruction syndrome (SOS)/veno-occlusive disease (VOD) is a complication after allogenic hematopoietic stem-cell transplantation (allo-HSCT) with high mortality. The purpose of this study was to assess the incidence and outcome of SOS in patients after allo-HSCT with the impact of ursodeoxycholic acid (UDCA) and low-dose heparin as SOS prophylaxis. Out of 1016 patients, 23 developed SOS, with a cumulative incidence of 2.3% (95% CI 1.3-3.3) 6 months after HSCT. Approximately one quarter of these patients (26.1%) had late-onset SOS. A high proportion were very severe SOS cases (74%), and 83% of the patients were treated with defibrotide (DF). In multivariate analysis, advanced disease (p = 0.003), previous HSCT (p = 0.025) and graft versus host disease (GvHD) prophylaxis by post-transplant cyclophosphamide (PTCy) (p = 0.055) were associated with the development of SOS. The 1-year overall survival (OS) was significantly lower in the SOS group compared to patients without SOS (13% versus 70%, p = 0.0001). In conclusion, we found a low incidence of SOS in patients receiving low-dose heparin and UDCA prophylactically, but among SOS patients, a high mortality. Low-dose heparin and UDCA might be a prophylactic approach for SOS.

Early vascular endothelial complications after hematopoietic cell transplantation: Role of the endotheliopathy in biomarkers and target therapies development

This work aims to review the role of endothelial dysfunction underlying the main complications appearing early after autologous and allogeneic hematopoietic cell transplantation (HCT). The endothelial damage as the pathophysiological substrate of sinusoidal obstruction syndrome (SOS) is well established. However, there is growing evidence of the involvement of endothelial dysfunction in other complications, such as acute graft-versus-host disease (aGVHD) and transplant-associated thrombotic microangiopathy (TA-TMAs). Moreover, HCT-related endotheliopathy is not only limited to the HCT setting, as there is increasing evidence of its implication in complications derived from other cellular therapies. We also review the incidence and the risk factors of the main HCT complications and the biological evidence of the endothelial involvement and other linked pathways in their development. In addition, we cover the state of the art regarding the potential use of the biomarkers of endotheliopathy in the prediction, the early diagnosis, and the follow-up of the HCT complications and summarize current knowledge points to the endothelium and the other linked pathways described as potential targets for the prevention and treatment of HCT-complications. Lastly, the endothelium-focused therapeutic strategies that are emerging and might have a potential impact on the survival and quality of life of post-HCT-patients are additionally reviewed.

Role of the lectin pathway of complement in hematopoietic stem cell transplantation-associated endothelial injury and thrombotic microangiopathy

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a life-threatening syndrome that occurs in adult and pediatric patients after hematopoietic stem cell transplantation. Nonspecific symptoms, heterogeneity within study populations, and variability among current diagnostic criteria contribute to misdiagnosis and underdiagnosis of this syndrome. Hematopoietic stem cell transplantation and associated risk factors precipitate endothelial injury, leading to HSCT-TMA and other endothelial injury syndromes such as hepatic veno-occlusive disease/sinusoidal obstruction syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, capillary leak syndrome, and graft-versus-host disease. Endothelial injury can trigger activation of the complement system, promoting inflammation and the development of endothelial injury syndromes, ultimately leading to organ damage and failure. In particular, the lectin pathway of complement is activated by damage-associated molecular patterns (DAMPs) on the surface of injured endothelial cells. Pattern-recognition molecules such as mannose-binding lectin (MBL), collectins, and ficolins—collectively termed lectins—bind to DAMPs on injured host cells, forming activation complexes with MBL-associated serine proteases 1, 2, and 3 (MASP-1, MASP-2, and MASP-3). Activation of the lectin pathway may also trigger the coagulation cascade via MASP-2 cleavage of prothrombin to thrombin. Together, activation of complement and the coagulation cascade lead to a procoagulant state that may result in development of HSCT-TMA. Several complement inhibitors targeting various complement pathways are in clinical trials for the treatment of HSCT-TMA. In this article, we review the role of the complement system in HSCT-TMA pathogenesis, with a focus on the lectin pathway.

Hepatic sinusoidal obstruction syndrome/veno-occlusive disease after hematopoietic cell transplantation: historical and current considerations in Korea

Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a rare but severe complication of hematopoietic cell transplantation (HCT) showing high mortality. Multiple risk factors for SOS/VOD were identified, but it is often confused with other hepatic complications due to nonspecific clinical features. Therefore, diagnostic and severity criteria have been revised several times. The European Society of Blood and Marrow Transplantation suggested a new guideline that excludes the standard duration of development within 21 days, emphasizes late-onset SOS/VOD, and suggests the importance of Doppler ultrasonography. The severity criteria were further subdivided for guidance to begin active treatment using defibrotide which was approved in Korea since 2016. In a phase 3 trial, defibrotide had superior 100-day survival, compared to best available treatments (38.2% vs. 25.0%). Although several studies of SOS/VOD in Korean patients have been performed after the implementation of HCT, most involved small number of pediatric patients. Recently, the Korean Society of Blood and Marrow Transplantation investigated the incidence of SOS/VOD in the Korean population, and several influential studies of adult patients were published. Here, we summarize recent issues regarding the mechanism, diagnosis, severity criteria, prevention, and treatments of SOS/VOD in Korean patients, as well as recent analyses of nationwide incidence.

Defibrotide: Real World Management of Veno-Occlusive Disease/ Sinusoidal Obstructive Syndrome after Stem Cell Transplant

Hepatic veno-occlusive disease or sinusoidal obstructive syndrome (VOD/ SOS) is a life-threatening complication of hematopoietic stem cell transplantation (HSCT). Defibrotide is the only FDA-approved medication for the management of severe VOD/ SOS after HSCT. We report our center's experience with commercially available defibrotide as treatment for patients with VOD/SOS. We retrospectively identified 28 cases of VOD/ SOS, based on the European Society for Blood and Marrow Transplantation criteria, from March 2016 through June 2019. The median day of VOD/ SOS onset was 25 days (range, 8 to 69) and defibrotide was initiated on day of diagnosis in 71% of patients. Complete resolution of VOD/ SOS occurred in 75% of patients. Day +100 survival was 64% for all HSCT patients and 53% for those with very severe VOD/ SOS. Response rates and survival were similar in patients with VOD/SOS after myeloablative or reduced intensity chemotherapy HSCT. Therapy related adverse events were mild and included hematuria (43%), epistaxis (18%) and hypotension (11%). Severe hemorrhagic adverse events occurred in 2 patients (pulmonary and upper gastrointestinal hemorrhage; 7%) and both in the setting of progressive VOD/SOS. Early diagnosis, prompt initiation of defibrotide, and minimizing dosing interruptions may be key to successful treatment of VOD/ SOS.

Endothelial cell dysfunction: a key determinant for the outcome of allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloSCT) carries the promise of cure for many malignant and non-malignant diseases of the lympho-hematopoietic system. Although outcome has improved considerably since the pioneering Seattle achievements more than 5 decades ago, non-relapse mortality (NRM) remains a major burden of alloSCT. There is increasing evidence that endothelial dysfunction is involved in many of the life-threatening complications of alloSCT, such as sinusoidal obstruction syndrome/venoocclusive disease, transplant-associated thrombotic microangiopathy, and refractory acute graft-versus host disease. This review delineates the role of the endothelium in severe complications after alloSCT and describes the current status of search for biomarkers predicting endothelial complications, including markers of endothelial vulnerability and markers of endothelial injury. Finally, implications of our current understanding of transplant-associated endothelial pathology for prevention and management of complications after alloSCT are discussed.

Endothelial dysfunction and vascular complications after allogeneic hematopoietic cell transplantation: an expert analysis

Allogeneic hematopoietic cell transplantation (alloHCT) is the standard of care for many diseases. However, survivors often present with serious complications resulting from acute and chronic toxicities and it is crucial to increase consciousness from treating physicians. We performed a comprehensive review of the literature and critically examined recent available data, mostly using the PubMed and Medline search engines for original articles published over the last decade. Better understanding of many alloHCT-related disorders has shown that endothelial injury and vascular damage plays a critical role. The most widely studied endothelial injury syndromes (EIS) are veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), graft-versus-host-disease (GVHD), and transplant-associated thrombotic microangiopathy (TA-TMA). TA-TMA, frequently underdiagnosed, needs to be clarified using certain criteria and, as a life-threatening condition, requires immediate and intensive treatment. The first-in-class complement inhibitor eculizumab has significantly improved outcomes in both the pediatric and adult population. Cardiovascular (CV) events are the second major cause of morbidity and mortality of alloHCT survivors, after GVHD. Long-term monitoring and management of CV risk is expected to also incorporate patient stratification with CV risk prediction models, early markers of vascular dysfunction or procoagulant activity, subclinical target organ damage, arterial stiffness, and subclinical atherosclerosis.

Critical Care of Hematopoietic Stem Cell Transplant Patients

Life-threatening complications are frequent after hematopoietic stem cell transplant (HSCT), and optimum critical care is essential to ensuring good outcomes. The immunologic consequences of HSCT result in a markedly different host response to critical illness. Infection is the most common cause of critical illness but noninfectious complications are frequent. Respiratory failure or sepsis are the typical presentations but the sequelae of HSCT can affect nearly any organ system. Pattern recognition can facilitate anticipation and early intervention in post-HSCT critical illness. HSCT critical care is a multidisciplinary endeavor. Continued investigation and focus on process improvement will continue to improve outcomes.