Heterogeneous response to recombinant thrombomodulin by grade of sinusoidal obstructive syndrome after pediatric stem cell transplantation

Efficacy and Safety of Recombinant Thrombomodulin for the Prophylaxis of Veno-Occlusive Complication in Allogeneiccit Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

Hepatic veno-occlusive disease (VOD), also termed as sinusoidal obstruction syndrome (SOS), is a lethal complication after hematopoietic stem cell transplantation (HSCT). Various factors put patients undergoing allogeneic HSCT at an increased risk for VOD. Thrombomodulin (TM) is an important factor which has a wide range of effects, including anticoagulant, anti-inflammatory, angiogenic, and protective effect, on endothelial cells. It plays a role in preventing excessive coagulation and thrombosis by binding with thrombin and inhibiting the coagulation cascade. There are a limited number of options for the prevention of this fatal complication. Recombinant thrombomodulin (rTM), an endothelial anticoagulant co-factor, as prophylactic therapy might be able to prevent veno-occlusive complications after stem cell transplantation.

METHODS

A literature search was performed on PubMed, Embase, and Web of Science. We used the following Mesh terms and Emtree terms, "Hepatic Veno-Occlusive Diseases" OR "Sinusoidal Obstruction" OR "Stem Cell Transplantations " AND "Thrombomodulin" from the inception of data up to April 1, 2021. The PICO (Patient/Population, Intervention, Comparison and Outcomes) framework was used for the literature search.

RESULTS

For the VOD incidence after HSCTstem cell transplantation, the result was in favor of rTM with a risk ratio (RR) of 0.53 (I² = 0%, 95% confidence interval [CI] = 0.32-0.89). The incidence of transplant-associated thrombotic microangiopathy (TA-TMA) after HSCT was reduced in rTM group. The RR for incidence of TA-TMA was 0.48 (I² = 62%, 95% CI = 0.20-1.17) favoring rTM. The RR for incidence of graft-versus-host disease (GvHD) was also lower in rTM group, 0.48 (I² = 64%, 95% CI = 0.32-0.72).

CONCLUSION

In our meta-analysis, we evaluate the efficacy and safety of rTM in the prevention of SOS after HSCT. According to our results, rTM use led to a significant reduction in SOS episodes, TA-TMA, and GvHD after HSCT.

Endothelial Dysfunction after Hematopoietic Stem Cell Transplantation: A Review Based on Physiopathology

Endothelial dysfunction (ED) is frequently encountered in transplant medicine. ED is an argument of high complexity, and its understanding requires a wide spectrum of knowledge based on many fields of basic sciences such as molecular biology, immunology, and pathology. After hematopoietic stem cell transplantation (HSCT), ED participates in the pathogenesis of various complications such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), graft-versus-host disease (GVHD), transplant-associated thrombotic microangiopathy (TA-TMA), idiopathic pneumonia syndrome (IPS), capillary leak syndrome (CLS), and engraftment syndrome (ES). In the first part of the present manuscript, we briefly review some biological aspects of factors involved in ED: adhesion molecules, cytokines, Toll-like receptors, complement, angiopoietin-1, angiopoietin-2, thrombomodulin, high-mobility group B-1 protein, nitric oxide, glycocalyx, coagulation cascade. In the second part, we review the abnormalities of these factors found in the ED complications associated with HSCT. In the third part, a review of agents used in the treatment of ED after HSCT is presented.

Advances in the diagnosis and treatment of disseminated intravascular coagulation in haematological malignancies

Haematological malignancies, including acute leukaemia and non-Hodgkin lymphoma, are one of the underlying diseases that frequently cause disseminated intravascular coagulation (DIC), an acquired thrombotic disorder. Concomitant DIC is associated with the severity of the underlying disease and poor prognosis. The Japanese Society on Thrombosis and Hemostasis released the new DIC diagnostic criteria in 2017. This criteria include coagulation markers such as soluble fibrin and the thrombin-antithrombin complex to more accurately evaluate the hypercoagulable state in patients. Among several groups of anticoagulants available, recombinant human soluble thrombomodulin is most frequently used to treat DIC caused by haematological malignancies in Japan. DIC is remitted in parallel with the improvement of the underlying haematological diseases; thus, there is room for debate regarding whether the treatment of DIC would improve the prognosis of patients. Haematopoietic stem cell transplantation as well as the recently introduced chimeric antigen receptor (CAR)-T-cell therapy are innovative therapies to produce a cure in a subset of patients with haematological malignancies. However, coagulopathy frequently occurs after these therapies, which limits the success of the treatment. For example, DIC is noted in approximately 50% of patients after CAT-T-cell therapy in conjunction with cytokine release syndrome. Hematopoietic stem cell transplantation (HSCT) causes endotheliitis, which triggers coagulopathy and the development of potentially lethal complications, such as sinusoidal obstruction syndrome/veno-occlusive disease and transplant-associated thrombotic microangiopathy. This review article describes the pathogenesis, clinical manifestation, diagnosis, and treatment of DIC caused by haematological malignancies, CAR-T-cell therapy, and HSCT.

Effects of recombinant thrombomodulin therapy and soluble human leukocyte antigen-G levels during hematopoietic stem cell transplantation

BACKGROUND

Conditioning chemotherapies for hematopoietic stem cell transplantation (HSCT), especially those that include total body irradiation, can result in serious complications such as graft-versus-host disease (GVHD). Human leukocyte antigen G (HLA-G) is a non-classical class I molecule with multiple immunoregulatory functions.

METHODS

We measured interleukin (IL)-10, transforming growth factor (TGF)β₁, and soluble HLA-G (sHLA-G) in HSCT patients and examined the relationship between sHLA-G levels and acute GVHD (aGVHD). Additionally, we investigated the effect of recombinant soluble thrombomodulin (rTM) therapy on sHLA-G levels. Our study cohort included 135 patients who underwent allogeneic HSCT at several institutions in Japan.

RESULTS

Serum levels of IL-10 and TGFβ₁ exhibited no significant changes following HSCT. In contrast, levels of sHLA-G were significantly increased at days 21 and 28 post-HSCT. For patients with confirmed complications, the frequency of aGVHD was significantly lower in those with a > 2.8-fold increase in sHLA-G levels at day 28 relative to day 7 post-HSCT. sHLA-G levels in patients who received rTM therapy were significantly higher at days 21 and 28 post-HSCT compared with those in patients who did not receive rTM therapy.

CONCLUSION

These data suggest that HLA-G/sHLA-G participate in prevention of GVHD, and that rTM may prevent aGVHD following HSCT by promoting elevation of sHLA-G.

Prophylactic recombinant thrombomodulin treatment prevents hepatic sinusoidal obstruction syndrome in high-risk pediatric patients that undergo hematopoietic stem cell transplants

Hepatic SOS is a potentially life-threatening complication of conditioning for allogeneic HSCT. rTM is a new drug for treating DIC. We report our experience of the use of rTM as a prophylaxis against SOS in high-risk pediatric patients that underwent HSCT. We evaluated the cases of 19 pediatric hematology and oncology patients who underwent HSCT at our institution between 2007 and 2016. The patients who received HSCT after 2012 (n = 8) were treated with rTM as a prophylaxis against SOS together with UDCA and LMWH, whereas the others (n = 11) were only treated with UDCA and LMWH. Although SOS occurred by post-HSCT day 35 in 3 (27%) patients in the control group, SOS was not seen in the rTM group. Two of the former three patients suffered severe SOS, and one died of the condition. The mean peak level of PAI-1 (a marker of endothelial damage) was significantly lower in the rTM group. rTM appears to be a safe prophylaxis for SOS. The present findings suggest that prophylactic rTM after HSCT might help to prevent SOS.

Clinical effects of recombinant thrombomodulin and defibrotide on sinusoidal obstruction syndrome after allogeneic hematopoietic stem cell transplantation

Sinusoidal obstruction syndrome (SOS) is a lethal complication after hematopoietic stem cell transplantation (HSCT). Defibrotide (DF) is the only drug internationally recommended for SOS treatment in Western countries. Recombinant human soluble thrombomodulin (rhTM), which is promising for the treatment of patients with disseminated intravascular coagulation, is also reported to be potentially effective for SOS. To clarify the safety and efficacy of DF and rhTM, we conducted a retrospective survey of these agents in Japan. Data from 65 patients who underwent allogeneic HSCT and received DF (n  =  24) or rhTM (n  =  41) for SOS treatment were collected. The complete response rates for SOS on day 100 were 50% and 54% in the DF and rhTM groups, respectively. The 100-day overall survival rates were 50% in the DF group, and 48% in the rhTM group. Several severe hemorrhagic adverse events were observed in one patient in the DF group and five patients in the rhTM group. The main causes of death were SOS-related death, and no patient died of direct adverse events of DF or rhTM. Our results suggest that rhTM, as well as DF, can be effective as a novel treatment option for SOS.