Effect of Lumacaftor/Ivacaftor on Pulmonary Exacerbation Rates in Members with Cystic Fibrosis in a Medicaid Population.

Abstract

Lumacaftor/ivacaftor (LUM/IVA) is indicated for patients with cystic fibrosis (CF) homozygous for the F508del mutation in the CFTR gene. In clinical trials, LUM/IVA decreased pulmonary exacerbation rates. To our knowledge, there is no published data evaluating real-world outcomes for Medicaid patients receiving LUM/IVA. To compare CF pulmonary exacerbation rates before and after initiation of LUM/IVA in 1 state's Medicaid program. This pre-post claims analysis screened fee-for-service and managed Medicaid members who had ≥ 1 pharmacy claim for LUM/IVA between July 2, 2015, and September 30, 2016. Members were included if they were aged ≥ 6 years with a CF diagnosis and homozygous for the F508del mutation, consistent with the indication at study initiation. Exclusion criteria included Medicaid as a secondary payer or any break in coverage during the study. The index date was defined as the first claim for LUM/IVA. Demographics and outcomes were derived from pharmacy and medical claims. Outcomes included overall rate of pulmonary exacerbations (reported as the total events for the study population 6 months before and after the index date and average annualized rate). Pulmonary exacerbation was defined as any combination of medical claims for an emergency room (ER) visit or inpatient hospitalization with a CF pulmonary exacerbation or respiratory infection (ICD-9/10-CM codes) or pharmacy claims for an oral or intravenous antibiotic (excluding macrolides). A gap of > 7 days was considered a new pulmonary exacerbation. Paired t-test was used to test significance. 21 patients met inclusion criteria with an average age at treatment initiation of 20.1 years. Average proportion of days covered (SD) was 0.62 (0.29). The number of pulmonary exacerbations increased from 45 to 48 during the 6 months before and after the index date, respectively, and the annualized rate increased from 4.37 to 4.66 (P = 0.69). While the number of pulmonary exacerbations associated with antibiotics alone increased (23 to 33; P = 0.08), those associated with at least 1 ER visit or inpatient hospitalization decreased (22 to 15; P = 0.08). This analysis did not find a decrease in pulmonary exacerbation rate for Medicaid members receiving LUM/IVA; however, adherence was low. Further study of similar populations is needed to better understand the long-term effect of treatment. No outside funding supported this study. The authors have nothing to disclose. A poster of this project was presented at the Academy of Managed Care Pharmacy Managed Care & Specialty Pharmacy Annual Meeting 2018 in Boston, MA, on April 23-26, 2018.