Pfizer has dosed the first participant in the Phase III CIFFREO study of investigational gene therapy candidate PF-06939926 in boys with Duchenne muscular dystrophy (DMD).
PF-06939926 is a recombinant adeno-associated virus serotype 9 (rAAV9) capsid carrying a mini-dystrophin under human muscle-specific promotor’s control.
An X-linked disease, DMD is caused by mutations in the gene encoding dystrophin, which is essential for muscle membrane stability.
The global multi-centre, randomised, double-blind, placebo-controlled study will analyse the efficacy and safety of PF-06939926 in boys with DMD.
It will enrol 99 ambulatory male patients aged four to seven years across 55 clinical trial sites in 15 countries.
The change from baseline in the North Star Ambulatory Assessment (NSAA) at one year will form the trial’s primary endpoint.
Irrespective of the arm, eligible subjects will be given the gene therapy, either at the beginning of the study or after a year following treatment with placebo.
Study subjects will be followed up for five years after the treatment.
Pfizer Global Product Development Rare Disease chief development officer Brenda Cooperstone said: “The initiation of our pivotal trial, which is the first Phase III DMD gene therapy programme to begin enrolling eligible participants, is an important milestone for the community because there are currently no approved disease-modifying treatment options available for all genetic forms of DMD.
“We believe our gene therapy candidate, if successful in Phase III and approved, has the potential to significantly improve the trajectory of DMD disease progression, and we are working with worldwide regulatory authorities to initiate this program as quickly as possible in other countries.”
In May last year, Pfizer reported new data from the Phase Ib clinical trial of PF-06939926 for the treatment of patients with DMD.
The US Food and Drug Administration granted ‘Fast Track’ designation to PF-06939926 in October last year.