May 4, 2021 / Clinical Trials

Pfizer Shares Update on CIFFREO Phase 3 Gene Therapy Trial

Today Pfizer shared an update regarding their Phase 3 gene therapy trial, CIFFREO, with the community. While Pfizer has not yet opened sites within the U.S., the study is underway at 14 trial sites across 8 countries. Pfizer is actively working with the FDA to address outstanding questions with their investigational new drug (IND) submission in order to open clinical trial sites in the U.S. The delay in opening sites in the U.S. is focused on technical issues with a potency assay (the tool used to measure the ability of a drug to elicit a particular response at a certain dose in a given biological system), which has been accepted for use in other countries.

While Pfizer is working diligently to resolve the issue, they do not expect resolution in the first half of 2021. PPMD will be sure to share any announcements regarding updates to the CIFFREO trial and ensure the community is aware of site openings in the U.S. when available.

Read Pfizer’s update

In line with our continued efforts to work with the Duchenne community and share information as it becomes available, we would like to provide an update on the ongoing clinical development of PF-06939926, our gene therapy candidate for Duchenne muscular dystrophy (DMD), for which we now have an approved generic name, fordadistrogene movaparvovec.

We are progressing our Phase 3 trial, CIFFREO. To date, we have opened 14 trial sites in 8 countries (Italy, Spain, Israel, UK, S. Korea, Japan, Russia and Canada).

In the U.S., we are actively working with the FDA to address outstanding questions regarding our investigational new drug (IND) FDA application, including technical aspects of our potency assays, so that we can begin enrolling patients in Phase 3 US study sites. While we have high confidence in our current quality control overall and with our potency assays, which have been accepted in countries outside of the US, the FDA has additional technical requests that we are working to address as quickly as possible.

We understand the sense of urgency among many families and advocacy organizations in the U.S. who were hoping for sites to open soon. However, at this time, we cannot speculate as to when sites may open in the U.S., but do not expect a resolution in the first half of 2021.

We want to assure you that we are working diligently and hope to reach alignment with the FDA as soon as possible. In the interim, we will continue to progress our trial globally and enroll patients at other sites, which we believe will allow our program to remain on track to potentially enable approvals around the world, including the U.S.

We want to thank the Duchenne community for your trust and collaboration and assure you that we are working as quickly as we can to bring this potential treatment to patients.


The CIFFREO team

Pfizer Rare Disease
Global Product Development

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