Prophylactic Use of a Combination of an Anticoagulant and Ursodeoxycholic Acid for Sinusoidal Obstruction Syndrome after Allogeneic Myeloablative Hematopoietic Stem Cell Transplantation
Authors: Okamura Hiroshi , Nishimoto Mitsutaka , Nakane Takahiko , Koh Hideo , Nakashima Yasuhiro , Takeoka Yasunobu , Nakamae Mika , Hirose Asao , Hino Masayuki , Nakamae Hirohisa 
Published: October 2019

Abstract
Introduction:
Sinusoidal obstruction syndrome (SOS) is one of the potentially fatal complications of hematopoietic stem cell transplantation (HSCT). In particular, severe SOS frequently leads to multiple organ failure, and a worse prognosis. Thus, prophylaxis against development of SOS could contribute improved survival after HSCT.
Previous reports demonstrated the effectiveness of the prophylactic use of ursodeoxycholic acid (UDCA) or certain anticoagulants, including unfractionated and low-molecular-weight heparin, for SOS. In two randomized controlled trials and two meta-analyses it was reported that UDCA, a hydrophilic bile acid, was an effective and safe drug for prophylaxis against SOS. The usefulness and feasibility of prophylactic use of anticoagulants after allogeneic HSCT are however still controversial. In addition, to our knowledge no study has evaluated the feasibility of usage of UDCA combined with an anticoagulant for SOS prevention after allogeneic HSCT in adult patients.
To assess the efficacy and safety of use of UDCA combined with an anticoagulant as SOS prophylaxis, we performed a retrospective cohort study to examine the occurrences of SOS and hemorrhagic events in patients who underwent myeloablative allogeneic HSCT at our institution. We examined use of any anticoagulant together with simultaneous administration of UDCA, in comparison with UDCA alone for the prevention of SOS.
Patients and methods:
We reviewed the charts of consecutive adult patients in whom myeloablative allogeneic HSCT was performed at our hospital from November 1994 to May 2014, and who received either unfractionated heparin or dalteparin (low-molecular-weight heparin) with UDCA (group 1), danaparoid with UDCA (group 2), or UDCA only (group 3), used for prophylaxis against SOS.
Results:
A total of 280 patients (group 1: n=52; group 2: n=33; and group 3: n=195) were investigated. The proportions of patients with risk factors for SOS-including non-remission at the time of HSCT, a second or subsequent HSCT, high aspartate aminotransferase (AST) levels before HSCT, high ferritin levels before HSCT, a history of receiving gemtuzumab ozogamicin, and HLA disparity-were similar across the three groups. In group 1, a conditioning regimen containing busulfan was used less frequently (P = 0.002).
SOS occurred in seven patients (13.7%) in group 1, five patients (15.2%) in group 2, and 28 patients (14.4%) in group 3, all meeting the Seattle criteria. None of the patients in group 1, two (6.1%) in group 2, and nine (4.6%) in group 3 had SOS diagnosed according to the Baltimore criteria. There was no significant difference in the incidence of SOS among the three groups. In addition, with regard to the cumulative incidence of severe SOS, no statistically significant difference was present among the three groups. The incidence of hemorrhagic events within 30 and 100 days following allogeneic HSCT was not significantly different across the three groups (30 days; 5.8%, 3.0%, 5.1%, P = 0.843, 100 days; 17.6%, 15.2%, 14.4%, P=0.843, respectively). Furthermore, the probabilities of OS and NRM until day 100 after allogeneic HSCT were similar among the three groups (P = 0.733 and P = 0.637, respectively).
In a univariate model, a history of gemtuzumab ozogamicin treatment, high serum ferritin levels before HSCT, an HLA mismatched donor, and non-complete remission of disease at the time of allogeneic HSCT were found to be significant risk factors for SOS. Multivariate analysis revealed that a history of gemtuzumab ozogamicin therapy, a mismatched HLA donor, and non-complete remission of disease at the time of allogeneic HSCT were significant and independent risk factors for SOS. In the multivariate as well as univariate analyses, combined administration of UDCA and any anticoagulant for SOS prophylaxis did not have a significant effect on the incidence SOS, when compared to prophylaxis with UDCA alone.
Conclusion:
Our study results suggest that the combined use of UDCA and an anticoagulant for SOS prophylaxis after myeloablative allogeneic HSCT in adult patients was not beneficial. Establishment of an optimal strategy for prophylaxis against SOS after HSCT is still needed.

Disclosures
Nakane: Mundipharma KK: Research Funding. Koh:Pfizer: Consultancy, Honoraria. Hino:Pfizer: Honoraria, Research Funding; Nippon Shinyaku: Honoraria, Speakers Bureau; Alexion: Honoraria, Research Funding. Nakamae:Mochida Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Novartis Pharma KK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel/accommodation/meeting expenses, Research Funding.