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Pfizer Initiates First Stage of Phase 3 Hemophilia B Gene Therapy Trial

July 17, 2018
Pfizer Initiates First Stage of Phase 3 Hemophilia B Gene Therapy Trial

Spark Therapeutics and Pfizer have announced that the latter company has initiated a phase 3 open-label, multi-center study to evaluate the efficacy and safety of current factor IX prophylaxis replacement therapy in the usual care setting. According to a recent Spark press release, the efficacy data obtained in this “lead-in” study will serve as the within-subject control group for those patients that enroll into the next part of the phase 3 trial, which will evaluate the efficacy and safety of the investigational hemophilia B therapy fidanacogene elaparvovec.

Previously referred to as SPK-9001, fidanacogene elaparvovec is designed with Spark’s proprietary bioengineered adeno-associated viruses (AAVs), which act as delivery vehicles, or vectors, to carry the genetic codes that stimulate FIX production. The therapeutic approach being evaluated in this trial employs a modified novel AAV vector to deliver the corrected FIX gene into liver cells where the protein is normally manufactured. Spark is developing SPK-9011 in collaboration with Pfizer Inc., as part of a program first established in 2014 to develop and commercialize novel gene therapy-based treatments for hemophilia B.

The interventional portion of the phase 3 study will enroll patients who have completed at least six months in the lead-in study. This recent development follows a May 2018 report of positive results from phase 1/2 clinical trials in which 15 hemophilia B patients who received a single administration of fidanacogene elaparvovec experienced an overall 98% reduction in their annualized bleeding rate.

“With the lead-in study now open and actively recruiting patients, we are excited to begin our phase 3 program evaluating fidanacogene elaparvovec for the treatment of hemophilia B,” said Brenda Cooperstone, MD, senior vice president and chief development officer, rare disease, Pfizer Global Product Development. “The current data suggest immense promise for the use of this potential one-time treatment option. We look forward to the opportunity to continue the progress achieved by Spark Therapeutics for patients living with hemophilia B.”

“We are pleased to have transitioned fidanacogene elaparvovec to Pfizer following the positive results of the ongoing phase 1/2 clinical trial,” said Katherine A. High, MD, president and head of research & development, Spark Therapeutics. “The initiation of the phase 3 program marks an important milestone toward our goal of one day potentially freeing patients with hemophilia B of the need for regular infusions, while potentially eliminating spontaneous bleeding.”

Source: Spark press release dated July 16, 2018