Background and Objective:
Patisiran is the first therapy based on short interfering RNA technology indicated for a lifelong treatment of hereditary transthyretin-mediated amyloidosis. It is administered through intravenous infusion at a dosage of 0.3 mg/kg of body weight (KBW) once every three weeks. Patisiran is supplied in single-use 10 mg/5mL vials, and any drug residues must be disposed of immediately; it is sold at an ex-factory price of €8,529.41/vial. This work aims to demonstrate how unifying patisiran administration sessions on a single day (‘Drug-Day’) for patients followed by different clinicians is advantageous for containing pharmaceutical expenditure.

Methods:
We conducted an observational study in an Italian Research Institute for Neurological Sciences (ISNB) in the period between February 2021 and November 2022, divided into two phases: Phase 1 (February 2021-March 2022) and Phase 2 (April-November 2022), corresponding to before and after the establishment of Drug-Days, respectively. Applying this model (Drug-Day), at the beginning of Phase 2 at the ISNB the nine patients undergoing treatment with patisiran were divided into two groups for two distinct drug administration sessions according to their body weight: the sum of the total body weight of each group was a value very close to a multiple of 33 (each vial covers 33.3 KBW).

Results:
During Phase 1 patisiran monthly wastage was on average 9.2% of the vials used; during Phase 2, we recorded a drug wastage of 1.8%. The data collected show that this strategy resulted in a saving of €27.29/KBW/administration and €32,480/model patient (70 KBW)/year (corresponding to 3.8 vials).

Conclusion:
This study showed that careful management of drug administration sessions, by reducing the leftover drug, allows creation of a more economically sustainable model and redirection of resources. Therefore, a multidisciplinary collaboration between different professionals is necessary for implementation of strategies to make pharmaceutical spending more sustainable.