Real-world treatment patterns among patients (pts) diagnosed with primary mediastinal large B-cell lymphoma (PMBCL) in the United States (US).

Abstract

e19050 Background: PMBCL is a rare mature B-cell neoplasm (2-4% of non-Hodgkin lymphomas) for which there is only limited data on treatment patterns in clinical practice. In October 2015, PMBCL was differentiated from diffuse large B-cell lymphoma (DLBCL) with the advent of ICD-10-CM PMBCL-specific codes. This study aims to describe real-world treatment patterns among pts diagnosed with PMBCL in the US. Methods: A retrospective database analysis was conducted using the Optum Clinformatics DataMart database (01/2013-03/2018). Pts with a first PMBCL ICD-10-CM diagnosis (with or without an antecedent ICD-10-CM diagnosis of DLBCL/other lymphoma, which may have been assigned before PMBCL confirmation) after October 1st, 2015 (index date) and no ICD-9-CM diagnosis code for unspecified PMBCL/DLBCL, were identified as incident pts. Those with PMBCL ICD-10-CM and unspecified ICD-9-CM diagnosis for PMBCL/DLBCL before October 2015 (index date) were identified as prevalent pts. PMBCL diagnoses on ≥2 medical visits and ≥12 months of continuous enrollment pre-index date were required. An adapted algorithm developed from previously published studies was used to identify lines of therapy (LOT). Duration of therapy spanned from LOT initiation up to discontinuation of all agents in the LOT, a switch to another LOT, or the addition of a new agent. Results: Among 148 PMBCL pts (118 incident; 30 prevalent), median (interquartile range) age was 66 (42-77) years. In incident pts, 48.3% were treated with ≥1 LOT (mean ± standard deviation [SD] duration of therapy: 86.0 ± 69.8 days) and 14.4% were treated with ≥2 LOT. The most frequently used first-line (1L) therapy (54.4% of pts) was R-CHOP (rituximab, cyclophosphamide, doxorubicin and vincristine). In prevalent pts, 63.3% were treated with ≥1 LOT (mean ± SD duration of therapy: 88.3 ± 44.6 days) and 20.0% were treated with ≥2 LOT. The most frequently used 1L therapy was R-CHOP (68.4%). Conclusions: This study demonstrated that a large portion of pts require additional therapy after 1L treatment to manage PMBCL, underscoring the significant unmet need in this population.