Costs to Medicare of Treating Chronic Lymphocytic Leukemia Patients with Alemtuzumab.
Authors: Lafeuille Marie-Hélène , Vekeman Francis , Kerrigan Matthew , Wang Si-Tien , Duh Mei 
Published: October 2019

Abstract
Abstract 2477
Poster Board II-454

Background:
Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia in the Western world, comprising over one-third of all new leukemia cases. Alemtuzumab is a humanized monoclonal antibody targeted to lymphocytes through the CD52 receptor that has been demonstrated to reduce the amount of malignant lymphocytes in patients with CLL. Alemtuzumab is, however, associated with various adverse events (AEs) including cytopenia, infections, and cardiac dysfunction. The current study aimed to quantify the incremental cost to Medicare of treating CLL patients with alemtuzumab.

Methods:
An analysis of patients' electronic health insurance claims records (1999-2007) from the Medicare 5% national sample was conducted. Patients with continuous enrollment for 3 or more months prior to their first observed claim with a CLL diagnosis, no more than two malignancies (by ICD-9 diagnostic codes associated with claims), and 1 or more claim for alemtuzumab were included in the analysis. Patients who had HMO coverage under Medicare were excluded from the analysis to ensure data completeness. A pre-post design was used to quantify the incremental costs associated with alemtuzumab by calculating health care costs within 6 months after alemtuzumab initiation relative to the 6-month period before alemtuzumab initiation. Mean monthly (per-patient per-month, PPPM) costs were calculated and were grouped by sites of care, service type, tests and procedures, treatment and drugs, and by AEs. To estimate the costs of AEs, claims with ICD-9 diagnostic codes for the AE of interest were grouped and mean PPPM costs were calculated for those groups. These groups were not mutually exclusive: claims could be associated with more than one diagnostic code. Statistical comparisons between the pre- and post-treatment periods were based on paired Student t-tests.

Results:
A total of 81 CLL patients treated with alemtuzumab formed the study population. The mean age (SD) was 75.2 (7.5) years and females represented 38.3% of the cohort. Patients were observed for an average of 50 months and mean time between the first observed CLL diagnosis and initiation of alemtuzumab treatment was 36 months. After alemtuzumab initiation, mean total healthcare costs increased from $4,272 to $10,385 PPPM (cost difference: $6,113, P<0.0001). Patients had a mean of 11.8 claims for alemtuzumab and the mean cost (SD) for alemtuzumab was $4,006 ($3,277) PPPM in the post-alemtuzumab period or 39% of total costs. Costs associated with diagnostic codes for cytopenia were $1,658 pre-alemtuzumab compared with $4,114 post-alemtuzumab (P<0.0001). In the pre- alemtuzumab period, costs with infection-related diagnostic codes were $107 PPPM compared with $841 in the post-alemtuzumab period (P=0.0005). Costs associated with cardiac dysfunction diagnostic codes were $766 PPPM in the pre-alemtuzumab period and $1,692 in the post-alemtuzumab period (P=0.0172) (Table 1). Note that these cost categories are not mutually exclusive.

Conclusions:
Amongst a cohort of Medicare fee-for-service patients with CLL, alemtuzumab was associated with a significant increase in healthcare costs in the 6 months after initiation of therapy of which the costs of alemtuzumab, oncology services, cytopenias, infections, and cardiac dysfunctions were large components.

Disclosures:
Lafeuille: Groupe d'analyse: Employment; GlaxoSmithKline: Research Funding. Vekeman:Groupe d'analyse: Employment; GlaxoSmithKline: Research Funding. Kerrigan:GlaxoSmithKline: Employment. Wang:Analysis Group: Employment; GlaxoSmithKline: Research Funding. Duh:GlaxoSmithKline: Research Funding; Analysis Group: Employment.