Tofersen: Silver Lining or Hyperbole?

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder of anterior horn cells with a dismal prognosis. Over a century since its description, we still do not have a cure for this disorder. Edaravone, Riluzole, and combination of phenylbutyrate and taurursodiol are a handful of FDA-approved drugs that only delay the progression of the disease by a few months. Tofersen, an antisense oligonucleotide, in SOD1 related ALS, has joined the bandwagon of FDA-approved drugs for ALS recently. It is a gene therapy that has been found to lower SOD1 concentrations and neurofilament light chain concentrations in blood and CSF, a known biomarker of ALS, leading to the accelerated approval of the drug. Although it did not show any statistically significant clinical improvement. In this article, we discuss the development and approval process of the first gene-based therapy, Tofersen, for ALS.