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Pfizer: Change in Gene Therapy Protocol

September 29, 2021

Pfizer has announced a change to its gene therapy clinical program.

Pfizer’s investigational gene therapy trial started recruitment in Canada in March 2021. They recently announced they will be changing their trial protocol to exclude patients with any mutation (exon deletion, duplication, insertion, or point mutation) affecting exons 9-13, or deletions that affect both exon 29 and exon 30. There were three serious adverse events that were believed to be related to the study drug and it is thought that certain mutations may be associated with a higher risk for these adverse events. As a result, Pfizer has proposed changes to their protocol to exclude the mutations described above:

“Three serious adverse events of muscle weakness, two of which involved myocarditis (inflammation of the heart tissue), recently occurred in the ongoing studies of fordadistrogene movaparvovec and were attributed to the study drug. Pfizer’s External Data Monitoring Committee reviewed the safety findings and concluded that certain mutations in the dystrophin gene may be associated with a higher risk for these adverse events following treatment with fordadistrogene movaparvovec.”

“Ensuring the safety of study participants is our first priority. As such, we have proposed a change to our study protocols with a new criterion that will exclude participation for DMD patients with any mutation (exon deletion, exon duplication, insertion, or point mutation) affecting exons 9 through 13, inclusive, or a deletion that affects both exon 29 and exon 30. These mutations are estimated to represent less than 15% of patients with DMD. The proposed changes in the protocol and supportive study documents are currently under review by regulatory authorities and ethics committees. Enrollment at each site must await approval by these governing bodies, which will happen at different times for individual countries and sites.”

The Pfizer DMD gene therapy team

We know this change will be very disappointing to families hoping to enroll in this study. If you have any questions about this announcement or need any further support, please contact us by emailing: [email protected].

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