Burden of Hospitalizations Due to Epstein-Barr Virus-Driven Post-Transplant Lymphoproliferative Disorder (EBV+PTLD) in Patients Who Failed First Line Rituximab or Rituximab Plus Chemotherapy Following Solid Organ Transplant (Post-SOT): A Retrospective Chart Review Study of German PTLD Registry
Authors: Zimmermann Heiner , Xu Hairong , Barlev Arie , Zhang Yang , Thirumalai Dhanalakshmi , Watson Crystal , Trappe Ralf Ulrich 
Published: February 2020

Background:
Post-transplant lymphoproliferative disorder (PTLD) is a rare and often aggressive disease in the setting of immunosuppression following solid organ transplant (post-SOT). About 50% of cases are associated with Epstein-Barr virus (EBV) infection of B cells, either due to reactivation of the virus after transplantation, or from primary EBV infection. Data remain very limited with respect to overall clinical and economic burden among EBV+PTLD patients (pts), particularly in the setting of pts who fail first line therapy. This retrospective chart review aimed to quantify the burden of hospitalization due to EBV+PTLD in post-SOT pts who failed first-line therapy in the real-world setting in Germany.
Study Design and Methods:
The German PTLD registry database was screened for pts with EBV+PTLD post-SOT who were refractory (failed to achieve complete [CR] or partial remission [PR]) to rituximab or rituximab plus chemotherapy (CT) or relapsed at any point after such therapy between 2000 to 2015. Pts with primary CNS PTLD were excluded. Pts without any outpatient visit or hospitalization record were excluded from the analysis (n of pts=1). Hospitalization data were reviewed by an experienced physician and adjudicated as PTLD relevant; details on diagnoses and procedures performed during hospitalization were collected from the first diagnosis of PTLD to the earliest of the following: death, loss to follow up or end of study period (Sep 1st, 2018). We estimated the mean number of hospitalizations, average length of inpatient stay per admission and the percentages of time spent in the hospital out of the total time following PTLD index date or treatment failure index date. The PTLD index date was defined as the first date of EBV+PTLD diagnosis; and the treatment failure index date was defined as the earliest date of pts who became refractory or relapsed to first-line therapy of rituximab or rituximab plus CT.
Results:
A total of 35 EBV+PTLD pts were analyzed. All had failed first line rituximab monotherapy. Median follow up time was 24.8 months from the PTLD index date. Median age at PTLD diagnosis was 47 years (range 18-75). Of these, 6 (17.1%) were polymorphic, 21 (60%) were diffuse large B cell lymphoma, 3 (8.6%) were Burkitt lymphoma, and 5 (14.3%) were other B-cell lymphoma. Among the 35 pts, 23 (65.7%) died: 12 from PTLD, 6 treatment-related, 1 from organ failure, and 4 from other causes. The vast majority of pts (29 out of 35) received CHOP-based CT following rituximab failure (2 other CT, 4 did not receive CT).
All pts (100%) had at least one inpatient hospitalization after PTLD diagnosis and 16 (45.7%) pts had at least one ICU admission following PTLD index date. The mean number of PTLD hospitalizations following PTLD index date was 4 (SD 3.2, range 1-12) and the mean average length of stay per hospitalization was 23.8 days (SD 22.6, range 2-94). The mean proportion of time spent in the hospital out of total time at risk from PTLD index date was 20.5% (SD 27.6, range 0.1-100) with an average of 9.5% of time spent in the ICU setting during hospitalization stay (SD 22, range 0-99.5).
The mean number of PTLD hospitalizations (n of pts=19) following first course CT failure index date was 2.1 (SD 1.9, range 0-7) and the mean average length of stay per hospitalization was 14.8 days (SD 8.6, range 6-31.6). The mean proportion of time spent in the hospital out of total time at risk from CT failure index date was 41.8% (SD 39.6, range 0-100) with an average of 26% time spent in the ICU setting (SD 39, range 0-100).
Conclusions:
This is the first study to quantify the hospitalization burden directly related to EBV+PTLD post-SOT in Germany. The results show that hospitalization burden in EBV+PTLD post-SOT pts failing first line rituximab monotherapy is substantial accounting for approximately 20% of patient's time after initial diagnosis of PTLD with around 10% spent in the ICU setting. This hospitalization burden is even higher and accounts for over 40% of time in pts after additional treatment failure to first CT with 26% spent in the ICU setting.

Disclosures
Zimmermann: Roche: Research Funding; Janssen: Other: Travel, accomodations expenses; Atara Biotherapeutics: Other: Travel, accomodations expenses, Research Funding; Celgene: Other: Travel, accomodations expenses. Xu:Atara Biotherapeutics: Employment, Equity Ownership. Barlev:Atara Biotherapeutics: Employment, Equity Ownership. Zhang:Atara Biotherapeutics: Employment, Equity Ownership. Thirumalai:Atara Biotherapeutics: Employment. Watson:Atara Biotherapeutics: Employment, Equity Ownership. Trappe:Atara Biotherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Other: Congress related travel support; Roche: Consultancy, Honoraria, Other: Congress related travel support, Research Funding; AbbVie: Consultancy, Other: Congress related travel support; Celgene: Other: Congress related travel support.