Duchenne muscular dystrophy (DMD) is a rare, severe, progressive muscle-wasting disease leading to disability and premature death. Patients lack the muscle membrane-stabilizing protein dystrophin. Antisense oligonucleotide (AON)-mediated exon skipping is a therapeutic approach that aims to induce production of partially functional dystrophins. Recently, an AON targeting exon 51 became the first of its class to be approved by the United States regulators [Food and Drug Administration (FDA)] for the treatment of DMD. A unique aspect of the exon-skipping approach for DMD is that, depending on the size and location of the mutation, different exons need to be skipped. This challenge raises a number of questions regarding the development and regulatory approval of those individual compounds. In this study, we present a perspective on those questions, following a European stakeholder meeting involving academics, regulators, and representatives from industry and patient organizations, and in the light of the most recent scientific and regulatory experience.

Improving and facilitating the process of making new drugs available to patients with multiple sclerosis (MS) requires cooperation among the regulators and other stakeholders. This cooperation will also positively contribute towards developing guidelines of the highest quality in medical, regulatory and scientific aspects. This would be beneficial both in areas that require further guideline development, but also in fields where existing guidance should be adapted to take into account evolution in science. Considering the input from all stakeholders, the European Medicines Agency confirmed its intention to update the relevant guideline and apply a flexible approach towards new drug development strategies in MS. This article is the first official position from the EU regulators, presenting the main changes to be expected in the guidance document.