Risk of Patients Developing Post-Transplant Lymphoproliferative Disorder within the First Year after an Allogeneic Hemopoietic Stem Cell Transplant, 2011 to 2016: A US Claims Database Analysis
Authors: Barlev Arie , Xu Hairong , Fulcher Nicole , Watson Crystal , Sruti Ila , Sudhindra Akshay 
Published: October 2019

Abstract
Introduction: Post-transplant lymphoproliferative disorder (PTLD) is a heterogenous disease that can develop after solid organ or allogeneic hemopoietic stem cell transplant (HCT). PTLD after HCT is primarily of the monomorphic subtype and driven by the Epstein-Barr Virus. It is an ultra-rare disease that follows an aggressive clinical course with poor outcomes and for which there is no approved standard treatment. The risk of PTLD after HCT in the current clinical setting is insufficiently quantified, and large-scale data from the US are lacking. The objective of this study was to estimate the incidence of PTLD after allogeneic HCT using a large US claims database.
Methods: A retrospective cohort study using the MarketScan Commercial and Medicare Supplemental database was conducted. Patients who received an allogeneic HCT between January 1, 2011 and December 31, 2016 with at least 6 months of continuous enrollment prior to allogeneic HCT were included in the analysis. PTLD cases were identified as having a diagnosis of PTLD (ICD-9 code 238.77 or ICD-10 code D47Z1) or one inpatient or two outpatient claims for preselected, clinically relevant lymphoma codes within 1-year post-transplant. Patients with a clinically relevant lymphoma diagnosis in the 6 months prior to HCT were excluded. The percentage of patients who developed PTLD during the first year after allogeneic HCT was calculated, the average time to PTLD diagnosis was estimated, and patient characteristics at PTLD diagnosis were described.
Results: A total of 2,735 eligible patients were included in the analysis; the mean (range) post-transplant follow-up time was 576 (1-2555) days. Overall, 103 patients (3.8%; 95% CI: 3.1%-4.6%) developed PTLD during the first year after allogeneic HCT, and the median (range) time from allogeneic HCT to PTLD diagnosis was 90 (0-364) days. The mean (SD) age at time of first PTLD diagnosis was 46.8 (17.2) years, with 84.5% of patients 18 to < 65 years old, 8.7% of patients < 18 years old, and 6.8% of patients ≥ 65 years old. There was a higher percentage of male versus female PTLD patients: 55.3% versus 44.7%.
Conclusions: This analysis of a large-scale US claims database showed that 3.8% (95%CI: 3.1%-4.6%) of post-allogeneic HCT patients had PTLD within the first year after transplant. Most patients impacted by PTLD were younger than 65 (93.2%), and a substantial proportion were pediatric patients (8.7%). Future studies are needed to better understand the disease state and burden of PTLD as well as the unmet medical need for this patient population.

Disclosures
Barlev: Atara Biotherapeutics, Inc: Employment, Equity Ownership. Xu:Atara Biotherapeutics, Inc: Employment, Equity Ownership. Fulcher:IBM Watson Health: Employment. Watson:Atara Biotherapeutics, Inc: Employment, Equity Ownership. Sruti:IBM Watson Health: Employment. Sudhindra:Atara Biotherapeutics, Inc: Employment, Equity Ownership.