Background and Importance Nusinersen is an antisense oligonucleotide that increases the production of full-length, functional survival of motor neuron (SMN) protein. It was the first disease modifying therapy approved for Spinal Muscular Atrophy 5q (SMA). SMA is a progressive neuromuscular rare disease, however the cost of available treatments implies a high economic burden for the sanitary system.

Aim and Objectives To analyse the economic advantage of treating SMA in clinical trials (CT) with nusinersen provided by the sponsor.

Material and Methods Retrospective, observational, single-centre, multidisciplinary economic study calculating the cost-saving impact of the use of intrathecal nusinersen in CT between February 2021 and September 2023.

Clinical data was extracted from Farmis-Oncofarm® and pkEnsayos®, whereas economic data [Laboratory Purchase Price (LPP) without Value-Added Tax (VAT)] was obtained from Orion-Logis®.

The variables analysed were age, anthropometric data (basal weight), diagnosis, pharmacotherapeutic data (cycles received and administrations) and consumption data (preparations and avoided costs). The results were expressed as: percentage, and median with interquartile range (IQR).

Results Two active CT for SMA using nusinersen were selected to be included: a phase II/III trial, and the phase III extension. Seven patients were treated with nusinersen in both CT: 5 paediatric patients (71.4%) and 2 adults (28.6%). The median paediatric age and weight were 2.8 years [IQR 2.5–7.4] and 10.0 kg [IQR 6.5–23.0], respectively. The adults’ median age and weight were respectively 34.8 years (31.4 y 38.1) and 78.5 kg (48.0 y 109.0).

A total of 53 drug preparations were made, with a median of nine per patient [IQR 5–9], that resulted in a total consumption of 1,394 mg (178 mg per patient [IQR 162–240]).The global cost-saving was 5,148,443.7 €, that represents annually an economic impact of 2,067,648.1 €.

The median treatment cost avoided per CT and patient were 2,574,221.9 € (2,415,410.5 y 2,733,033.3) and 598,312.7 € [IQR 3,871.3- 88,639.2], respectively.

Conclusion and Relevance SMA is considered one of the world’s most expensive treatment disease, and nusinersen is the standard of care. The promotion to participate in SMA CT allows access to innovative treatments for patients and hospitals with the aim of reducing the large underlying budgetary burden.

Conflict of Interest No conflict of interest.