The death of a young boy with Duchenne muscular dystrophy (DMD) who was treated with Pfizer’s experimental gene therapy in a phase 2 trial has prompted the company to pause dosing in another study.

The labelling puts it in direct contention with Pfizer's blockbuster Vyndamax/Vyndaqel/Vynmac franchise – based on tafamidis – which has been approved for ATTR-CM since 2019 and is also used ...