Persistence and Compliance of Deferoxamine Versus Deferasirox in Medicaid Patients with Sickle-Cell Disease.

Patients with sickle-cell disease (SCD) receiving chronic transfusions of red blood cells are at risk of developing serious adverse effects. Iron chelating therapies (ICTs) help eliminate iron surplus by binding with plasma iron to form a non-toxic conjugate that can be safely excreted from the body. Two iron chelating agents are currently available in the US: deferoxamine (DFO) is an injectable formulation and deferasirox (Exjade®) is an oral suspension. This study compared the frequency of hospitalizations, persistence, and compliance of SCD patients from Medicaid programs treated with DFO versus deferasirox.

An analysis of patients' electronic claims records from the Florida (1998-2007), Missouri (1993-2008), and New Jersey (1996-2008) Medicaid programs was conducted. Patients with continuous enrollment for at least six months prior to ICT initiation and ≥1 SCD diagnosis were included in the analysis. Patients were divided into four cohorts: patients treated with DFO (any DFO group) and patients treated with deferasirox (any deferasirox group); the latter was further divided into patients initiated on DFO and then switched to deferasirox (deferasirox switchers), and patients treated with deferasirox only (deferasirox only group). Frequency of hospitalization as well as length of stay pre- and post-ICT treatment initiation were assessed. Persistence was defined as time to drug discontinuation with at least one Rx gap, using Kaplan-Meier approach. Compliance was estimated using a medication possession ratio (MPR), calculated as the total days of supply divided by the number of days between the first and last dispensing plus the days of supply of the last dispensing.

A total of 217 (mean age=19.4), 275 (20.1), 105 (19.4), and 166 (20.4) patients were included in the any DFO, any deferasirox, deferasirox switchers, and deferasirox only groups, respectively. Exposure period, defined as the time from the date of the first dispensing to the end of the days supply of the last dispensing, was approximately two times longer in the DFO group than in the deferasirox groups (days, DFO: 783, any deferasirox: 353, deferasirox switchers: 416, deferasirox only groups: 317). After ICT initiation, both DFO and deferasirox groups experienced significant reduction in the frequency of hospitalizations relative to pre-treatment (DFO: from 0.92 to 0.64 hospitalizations per patient per month, P=.0010; any deferasirox: from 1.22 to 0.4, P<.0001). Median length of hospitalization stay remained similar after ICT initiation relative to pre-treatment in both the DFO group (pre- and post-ICT initiation: 3 days) and the any deferasirox group (from 3 days pre-ICT to 4 days post-ICT initiation). The Kaplan-Meier rates of medication persistence during the first year of ICT were significantly greater for all three deferasirox cohorts compared to the DFO cohort (see Table 1). Patients treated with deferasirox were significantly more compliant compared to the DFO group (see Table 2).

Based on a Medicaid population, deferasirox patients were more compliant and persistent to their treatment than those treated with DFO. Frequency of hospitalizations was significantly reduced in the observation period for all ICT treated patients, although the length of hospitalization stay remained similar. Prospective studies are warranted to validate these results.

Jordan:Analysis Group, Inc.: Consultancy. Vekeman:Analysis Group, Inc.: Employment; Novartis Pharmaceuticals Corporation: Research Funding. Sengupta:Analysis Group, Inc.: Employment; Novartis Pharmaceuticals Corporation: Research Funding. Corral:Novartis Pharmaceuticals Corporation: Employment. Guo:Novartis Pharmaceuticals Corporation: Employment. Duh:Novartis Pharmaceuticals Corporation: Research Funding; Analysis Group, Inc.: Employment.