Abstracts

Rationale: Infantile Spasms (IS) is a rare and devastating form of epilepsy with typical onset in the first year of life. Two FDA-approved drug treatments for IS are: repository corticotropin injection (RCI, or H.P. Acthar® Gel) and vigabatrin (VGB or Sabril).  According to the United States (US) Consensus Report and a recent survey of members of the Child Neurology Society, most neurologists use RCI as preferred first-line treatment for IS not caused by tuberous sclerosis (TS) and VGB as the first-line treatment of IS caused by TS. Given known variation in the management of IS and sparse information regarding real-world medication patterns, we sought to characterize medication use in patients with IS in the 90 days prior to initiating RCI. Methods: Truven MarketScan® claims data was used to identify commercially-insured US patients with an IS diagnosis (ICD-9-CM 345.60, ICD-10-CM G40.822) ≤1 year of age at initiation of RCI (“index date”) during 1/1/07-12/31/15. Enrollment was required 90 days prior (“pre-index”). Diagnosis codes and ordered patterns of use of drug classes of interest (corticosteroids [CS], VGB and other anti-epileptics [AEDs]) were evaluated pre-index, including overlapping (i.e. dispensed same day) and sequential/add-on (i.e. dispensed different days) use. Use of each drug class could reflect use of ≥1 agent. All-cause healthcare resource use [HCRU: outpatient (OP) including specialists, inpatient (IP), emergency room (ER) and medications dispensed through the pharmacy (Rx)] was assessed pre-index. Means, standard deviations (SD), and proportions (%) were generated. Results: 462 patients were identified (57.2% male, 60.2% in Preferred Provider Organizations; Table 1). In the 90 days prior to RCI, the top 5 diagnoses other than IS observed were other convulsions, acute upper respiratory infection (URI), esophageal reflux, unspecified epilepsy, and abnormal involuntary muscle movements. 53.9% of patients had not received other drug classes prior to RCI; 37.4% received 1 drug class and 8.6% received >1 drug class (Table 2). Among those receiving >1 drug class, 7 distinct patterns of drug class use were observed. Other AEDs, either alone (29.9%) or with other drug classes (8.4%), were most often dispensed. Mean (SD) all-cause HCRU was: 11.4 (10.0) for OP [2.5 (3.4) involving specialists], 0.4 (0.7) for ER, 1.0 (0.8) for IP, and 4.2 (4.9) for Rx dispensed. Conclusions: Management of IS patients in the 90 days prior to initiating RCI is heterogeneous based on varying medication regimens and frequent HCRU, particularly in the outpatient setting. Efforts to increase awareness, facilitate identification and standardize treatment of IS are warranted to improve outcomes and efficiencies in this vulnerable population of patients. Limitations include uncertainty regarding chronology of events (e.g. diagnosis vs. medication use) and association of medications with events (e.g. CS and URIs). We did not evaluate drug-level treatment variation in this analysis; therefore we likely underestimated heterogeneity in medication use. Funding: This study was funded by a grant to the University of Washington from Mallinckrodt Pharmaceuticals.