Title:
Dalfampridine prior authorization program: a cohort study.

Abstract:
Dalfampridine (Ampyra) is indicated to improve walking in patients with multiple sclerosis (MS) and was found to be effective in 35%-43% of individuals with MS in clinical trials. Dalfampridine may increase seizure risk, particularly in patients with renal impairment. A U.S. managed care expert consensus panel agreed that patient access to dalfampridine is best managed by a prior authorization (PA) in accordance with the FDA-approved labeling. To ensure safe and appropriate dalfampridine use, a health plan developed and implemented a 2-phase point-of-sale PA program.
To evaluate dalfampridine PA review decisions, utilization, and pharmacy expenditures following the implementation of a dalfampridine safety and clinical PA program compared with a group of dalfampridine utilizers unexposed to a PA program.
The study utilized retrospective administrative pharmacy claims data from a commercial health plan averaging 1.3 million members per month. The plan implemented a 2-phase dalfampridine safety and effectiveness PA program on August 1, 2010. A comparison group that did not implement the dalfampridine PA program was identified from a commercially insured population with approximately 350,000 members per month. Members in both groups were required to be continuously enrolled from August 1, 2010, through January 31, 2011. A member's earliest paid or rejected claim found from August 1, 2010, through October 31, 2010, was defined as the index claim. Dalfampridine-weighted 30-day supply claims were summed and compared between groups from index date through January 31, 2011. A pharmacy cost avoidance estimate was calculated using the difference in average claims per member from index claim through January 31, 2011, multiplied by dalfampridine wholesale acquisition cost. Overall, dalfampridine utilization was evaluated between the intervention and comparison populations from August 2010 (implementation of PA in intervention group) through December 2011. Linear regression and Poisson models were used to test the trend differences.
The 60 PA-exposed dalfampridine members' average follow-up was 157 days. Phase 1 approval was obtained by 32 (53.3%) members; 4 (6.7%) members received a denial because of renal impairment; 8 (13.3%) members received a denial due to inability to obtain walking time; 1 (1.7%) member with relapse-remitting MS was denied a PA due to no concomitant disease-modifying agent; and 15 (25.0%) members did not initiate the PA process. Phase 2 approval was obtained by 23 (38.3%) of the 60 members. The 60 PA members had a total of 126 claims and an average utilization of 2.1 (SD 1.8) claims per member. The 20 non-PA dalfampridine members' average follow-up was 157 days. The comparison group members had a total of 84 claims and an average utilization of 4.2 (SD 2.0) claims per member. The PA program resulted in an average of 2.1 (P  less than  0.001) fewer claims per member in the PA group. The total dalfampridine cost avoidance estimate was $143,010 or $0.03 per member per month. The overall measure of a monthly claims utilization difference over time was statistically significantly different at P  less than  0.001, using the linear regression slope trend test. The trend line slope was not statistically significantly different, P = 0.841, between the intervention and comparison populations.
The study indicates that a dalfampridine PA program potentially improved safety and minimized dalfampridine costs. A PA program is effective in selecting appropriate utilizers for initial therapy. Addition of care management may further optimize use by encouraging adherence and tracking patient response.