Pfizer Inc. (NYSE:PFE) and Spark Therapeutics (NASDAQ:ONCE) announced today that Pfizer initiated a Phase 3 open-label, multi-center, lead-in study (NCT03587116) to evaluate the efficacy and safety of current factor IX prophylaxis replacement therapy in the usual care setting. The factor IX prophylaxis efficacy data obtained in the lead-in study will serve as the within-subject control group for those patients that enroll into the next part of the Phase 3 study, which will evaluate the investigational gene therapy fidanacogene elaparvovec for the treatment of hemophilia B. The interventional portion of this pivotal Phase 3 study will enroll patients who have completed at least six months in the lead-in study. Fidanacogene elaparvovec is the official United States Adopted Name (USAN) and will become the Recommended International Nonproprietary Name (INN) for the therapy formerly known as SPK-9001 and PF-06838435.
The Phase 3 program was initiated following the transfer of the responsibility for Spark Therapeutics’ hemophilia B gene therapy program to Pfizer. Fidanacogene elaparvovec is a novel, investigational vector that contains a bio-engineered adeno-associated virus (AAV) capsid (protein shell) and a high-activity human coagulation factor IX gene. It is hoped that, once treated, patients will be able to produce factor IX themselves, rather than having to regularly inject factor IX.
“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.”
In May 2018, Pfizer and Spark Therapeutics announced data for 15 participants in the ongoing Phase 1/2 clinical trial of fidanacogene elaparvovec for the treatment of severe or moderately severe (FIX:C < 2 percent) hemophilia B. The findings showed all 15 patients had discontinued routine infusions of factor IX concentrates with no reported serious adverse events or thrombotic events as of the May 7, 2018 data cutoff.