Inclusion in limited distribution drug network reduces time to dalfampridine access in patients with multiple sclerosis at a health-system specialty pharmacy.

Dalfampridine improves walking speed in patients with multiple sclerosis (MS), but accessing specialty medications such as dalfampridine can be hindered by insurance restrictions, high costs, and limited distribution networks (LDNs) imposed by manufacturers. Some integrated health-systems specialty pharmacies (HSSPs) embed pharmacists in clinics and dispense medications from their internal pharmacies if included within the LDN. To assess access to dalfampridine in patients at an HSSP before and after gaining admission to the LDN. This study was conducted at Vanderbilt Specialty Pharmacy (VSP), an integrated HSSP at Vanderbilt University Medical Center (VUMC) with 2 clinical pharmacists embedded in the MS clinic. VSP gained access to the dalfampridine LDN on May 1, 2018, at which time the embedded pharmacists began to manage the comprehensive therapy initiation process. We performed a retrospective review of adult patients with MS who were prescribed dalfampridine from March 2010 to December 2018. Eligible prescriptions were new starts (no previous use) or restarts (after previous use and discontinuation). Prescriptions were classified as pre-VSP and post-VSP, which differentiates before and after VSP gained access to dispense dalfampridine. Study outcomes were insurance approval, initiation of therapy, and time from treatment decision to medication access. We used a proportional odds logistic regression model for time to medication access using the following covariates: pre-VSP versus post-VSP time period, insurance prior authorization (PA) denied versus approved/not needed, and baseline timed 25-foot walk. We included 262 patients and 290 prescriptions (260 pre-VSP and 30 post-VSP). In pre-VSP and post-VSP prescriptions, 97% were approved by insurance, and 93% of patients started therapy. Median time to medication access was 22 days (IQR = 11-45) for pre-VSP prescriptions and 1 day (IQR = 0-3) for post-VSP prescriptions. In the proportional odds logistic regression model, the odds of having a longer medication access time were significantly higher for pre-VSP prescriptions (OR = 83.219, < 0.001) and prescriptions whose PA was initially denied (OR = 9.50, < 0.001); 25-foot walk time was not significant (OR = 0.95, = 0.277). After obtaining access to dispense dalfampridine, the time to access therapy was reduced, suggesting that LDNs delay patient access to therapy at HSSPs. No funding was provided for this study. The authors have no conflicting interests to disclose. Preliminary results have been previously presented at the American Society of Health-Systems Pharmacy Midyear Meeting in December 2019, the Vanderbilt Health Systems Specialty Pharmacy Outcomes Research Summit in August 2020, and the National Association of Specialty Pharmacy Annual Meeting in September 2020.