Objective:
To examine whether a difference exists in factor consumption and cost after a person with factor VIII or factor IV switches from a standard half-life (SHL) factor product to an extended half-life (EHL) factor product managed by a single specialty pharmacy.
Methods:
All electronic medical records of patients with factor VIII or IX deficiencies who filled factor prescriptions with a single specialty pharmacy were reviewed. Data, including regimen, dosing and label instructions for fills of all recombinant and plasma-derived factor VIII and factor IX products between September 2013 and December 2017 were examined retrospectively. Adult patients (age ≥ 18 years) who switched from an SHL to an EHL product with 6 months of fill data available, for both periods before and after the initial EHL prescription was dispensed, were eligible for inclusion. Total cost was calculated using average wholesale price (AWP) using MediSpan (accessed June 1, 2018).
Summary:
Sixty-three (63) people with factor VIII deficiency and 29 people with factor IX deficiency met study criteria by having a prescription for factor and switching from an SHL product to an EHL product, as well as 6 months of dispensing prior to and after the change. The mean cost of therapy with an SHL factor VIII product for 6 months was $272,192 versus $455,260 for 6 months after switching to an EHL factor VIII product, an increase of 67%. The mean number of units of an SHL factor VIII product dispensed was 141,934 units compared to 181,688 units of an EHL factor VIII product per person, which is an increase of 28%. The mean cost of therapy with an SHL factor IX product for 6 months was $234,146 versus $474,858 for the 6 months after switching to an EHL factor IX product, an increase of 100%. The mean number of units of an EHL factor IX product dispensed was 147,730 units compared to 124,509 of an EHL factor IX product, a decrease of 16%.
Conclusion:
EHL products have several reported advantages over SHL products including longer interval between infusions, less frequent troughs (that may lead to decreased risk of bleeding episodes) and improved adherence. This analysis of dispensing data from a single specialty pharmacy indicates that change of prescription from SHL products to EHL products is associated with a higher cost of treatment. There are many more elements in factor prescribing that could contribute to future discussion.