RARE Daily

FDA Grants Priority Review to CSL Behring’s Hemophilia Gene Therapy

May 25, 2022

CSL Behring said that the U.S. Food and Drug Administration has accepted its Biologics License Application, for priority review, for etranacogene dezaparvovec, an experimental gene therapy for the treatment of adults with hemophilia B.

Hemophilia B is a life-threatening degenerative disease. People with the condition are particularly vulnerable to bleeds in their joints, muscles, and internal organs, leading to pain, swelling, and joint damage. Current treatment includes life-long prophylactic infusions of FIX to temporarily replace or supplement low levels of the blood-clotting factor.

Gene therapy has the potential to make more normal clotting ability possible in hemophilia B. Gene therapy achieves this with modified non-infectious viruses called “vectors” that can enter certain cells. Vectors carry genetic instructions to specific cells. Once delivered, the new genetic instructions allow the cellular machinery to produce their own stable levels of FIX. A certain type of vector, called an adeno-associated virus, or AAV, dissolves after delivering its genetic instructions. These genetic instructions remain in the target cells, but never actually become a part of a person’s own DNA.

The BLA is supported by results from the pivotal HOPE-B trial, the largest gene therapy trial in hemophilia B to date. People with Hemophilia B treated with etranacogene dezaparvovec demonstrated reduced adjusted annualized bleeding rate (ABR) by 64 percent and superiority to prophylaxis treatment at 18 months post-treatment compared to a 6-month run in period. The multi-year clinical development program for etranacogene dezaparvovec was led by uniQure and sponsorship of the clinical trials has transitioned to CSL Behring after its acquiring global rights to commercialize the investigational treatment.

Priority review of a BLA is reserved for medicines that, if approved, would be significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious conditions when compared to standard applications. Upon acceptance for priority review, the FDA goal is to take action on the BLA in six months as compared to 10 months for standard review. Previously, the European Medicines Agency accepted the Marketing Authorization application for etranacogene dezaparvovec under its accelerated assessment procedure.

Author: Rare Daily Staff

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