Pfizer tears up gene therapy timelines, revealing a series of phase 3 delays that end vision of a banner 2022

Pfizer’s vision for a banner 2022 in gene therapies is over. Having previously expected to post interim data on a trio of phase 3 programs next year, Pfizer has now delayed all the readouts, setting back its plans in hemophilia and Duchenne muscular dystrophy (DMD).

Multiple forces are behind the delays (PDF). In hemophilia A, Pfizer and partner Sangamo Therapeutics have voluntarily paused a phase 3 trial of their factor VIII gene therapy to change the protocol. The protocol change was prompted by the discovery that some patients had factor VIII activity of 150% or more, potentially raising their risk of blood clots.