Patterns Of Care, Survival, and Costs Of Second-Line Treatment In Medicare Beneficiaries With Diffuse Large B-Cell Lymphoma (DLBCL)
Authors: Danese Mark , Griffiths Robert , Gleeson Michelle , Dalvi Tapashi , Li Jingyi , Deeter Robert G , Mikhael Joseph R. , Dreyling Martin 
Published: October 2019

Abstract

Background
DLBCL is the most common subtype of non-Hodgkin's lymphoma. Approximately 50% of DLBCL patients are over age 65. Patterns of care and outcomes in older patients receiving second-line therapy for DLBCL have not been well-characterized.

Objective
We analyzed patterns of care, overall survival and costs of care in a cohort of older DLBCL patients receiving second-line therapy.

Methods
Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified a cohort age ≥66 with DLBCL diagnosed between 2000 and 2007. Patients had to receive first-line therapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or a CHOP-like regimen, with or without rituximab. Second-line treatment was defined as either (a) ≥1 new agents < 90 days after discontinuing all first-line agents (refractory disease), or (b) ≥1 agents (including first-line agents) ≥90 days after completion of first-line therapy (relapsed disease). Rituximab monotherapy was excluded (n=736). Patients were enrolled from 12 months prior to diagnosis and followed through 12/31/2009. Observation ended at death, change from coverage, or 12/31/2009. We reviewed the therapies of each patient and classified them into 1 of 3 groups: aggressive, conventional, or palliative. Direct costs to Medicare were calculated using paid amounts over the 24-month period after initiating second-line therapy, weighted to account for censoring, and inflated to 2009 US dollars.

Results
There were 5,716 first-line DLBCL patients of whom 632 (11%) received second-line therapy (206 refractory and 426 relapsed). The most common aggressive regimens were methotrexate (n=60), [carboplatin, cyclophosphamide and etoposide (n=54)] and [cisplatin, cytarabine, and etoposide (n=23)]. The most common conventional regimens were [cyclophosphamide, doxorubicin, and vincristine (n=74)], [cyclophosphamide and etoposide (n=31)]. The most common palliative regimens were etoposide (n=68), [cyclophosphamide and vincristine (n=56)], fludarabine (n=26), and gemcitabine (n=25). Median survival was 13.4 months. Overall, survival was not statistically significantly different among the different treatment approaches in multivariate-adjusted survival models. However, patient characteristics differed significantly between these treatment groups with patients receiving aggressive treatment being younger than in the palliative treatment group (>80 years: 9.1% vs 30.6%; p<0.0001). Similarly refractory patients were more frequent in the aggressive vs. conventional treatment group (53.4% vs. 11.3%; p<0.0001). Significant factors affecting survival included female gender (hazard ratio [HR] 0.65, 95% CI 0.53-0.80), absence of B symptoms at diagnosis (HR 0.69, 95% CI 0.53-0.89), and presence of anemia at diagnosis (HR 1.26, 95% CI 1.02-1.55. Multivariate adjusted, cumulative 24-month costs for the reference group for all model variables was $117,442 (95% CI $78,270 to $156,615). Significant factors that modified this cost were age 75-79 (relative to age 66-69; $-28,860), age ≥80 ($-42,262), extranodal involvement at diagnosis ($-15,421), and anemia at diagnosis ($+23,047).

Conclusions
Second-line therapy for refractory and relapsed DLBCL was associated with high mortality and costs in the Medicare population. While selection bias limits comparison of aggressive vs. conventional therapies, our findings suggest a substantial unmet need in the second-line setting.

Disclosures:
Danese: Genentech: Consultancy, Research Funding; Medimmune: Consultancy, Research Funding; Amgen: Consultancy, Research Funding. Griffiths:Amgen, Inc.: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; MedImmune: Consultancy, Research Funding. Gleeson:Amgen, Inc.: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; MedImmune: Consultancy, Research Funding. Dalvi:Medimmune: Employment, stock Other. Li:Medimmune: Employment, stock Other. Deeter:Medimmune: Consultancy, Employment, stock Other.