The impact of gene therapy on the treatment of Spinal Muscular Atrophy (SMA): A cost-benefit analysis of Zolgensma® therapy

Abstract

Spinal muscular atrophy is a rare autosomal recessive genetic disease linked to a mutation in a gene located on the long arm of chromosome 5 (5q13), involved in the deletion of the survival neuromotor gene (SMN1), causing the progressive loss of specialized nerve cells, affecting muscle movements and, in severe cases, leading to early death. Until 2019, patients with SMA were given palliative and continuous treatments, such as Nusinersena (Spinraza®) and Risdiplam (Evrysdi®). However, the introduction of Zolgensma®, an innovative technique that consists of replacing the defective SMN1 gene with healthy genes, through single-dose gene therapy, has changed this scenario, bringing the potential for a cure for the disease. The study evaluates the cost-benefit of Zolgensma®, which, although effective in replacing the altered genes, carries risks of side effects such as hepatotoxicity, requiring monitoring and prophylactic control. Regarding its cost compared to other available treatments, Zolgensma® is considered one of the most expensive treatments in the world to date. However, as it is a single-dose medication, it has an economic advantage, reducing the cost of treatment in the long term, while Spinraza® and Evrysdi® have continuous administration and accumulate significantly higher costs until the end of treatment. It is concluded that technological advances with gene therapy open new paths for the treatment of rare diseases and, despite the financial obstacles and discussion in the implementation of Zolgensma® in the public health system, the medication is a hope of life for patients with SMA and their families.