Spark Surges After Gene Therapy Helps 3 Hemophilia Patients

  • Clotting protein levels rise as high as 30 percent of normal
  • Drug is partnered with Pfizer, now in early-stage trial

Spark Therapeutics Inc. surged the most since October after the biotechnology company said its gene therapy helped three hemophilia B patients increase clotting ability enough to stop their regular infusion treatments.

The therapy, called SPK-9001, is co-owned by Pfizer Inc., which will take over development after Spark completes early-stage trials. The treatment gives patients a functioning copy of the gene that produces factor IX, a protein that clots blood. Spark rose 22 percent to $50.33 at 9:51 a.m. in New York, after earlier reaching $51.83.

Levels of factor IX stabilized at 28 percent of the normal level after 18 weeks in one patient and 30 percent after seven weeks in another, according to a statement from the companies Thursday. The study will be presented at the European Hematology Association’s annual meeting in June. A third patient was at 16 percent after three weeks.

Patients with more than 5 percent of the normal level are considered to have mild hemophilia, which means the bleeding is controlled unless they are in an unusual circumstance like an accident, according to Neil Frick, vice president of research and medical information at the National Hemophilia Foundation.

“You want to achieve a certain level of factor IX with consistency and durability,” without serious side effects, Spark’s Chief Executive Officer Jeff Marrazzo said by telephone. “From our perspective, it’s hitting all those things and exceeding the bar. We’re extremely excited.”

Eye Therapy

Spark, based in Philadelphia, may be one of the first drugmakers to bring a gene therapy to market in the U.S. Its lead product, a treatment for a rare inherited eye disorder, has improved patients’ visions in trials. The new data “demonstrates Spark’s ability in multiple target tissues, first in the eye and now the liver,” Marrazzo said. “That should give people confidence in our technology.”

“These are the highest levels of sustained factor IX expression that have been reported in hemophilia B gene therapy trials,” said Lindsey George, the lead researcher on the trial and an attending physician at The Children’s Hospital of Philadelphia.

George said she’s “cautiously optimistic,” and that more time is needed to prove the durability of the treatment and ensure that no safety issues appear over time.

No Bleeds

One of the three patients had a suspected ankle bleed two days after receiving treatment and gave himself an infusion. Other than that, there have been no bleeds or need for infusion for the three patients during the study period so far, according to the abstract. All the patients had severe hemophilia and needed regular infusions prior to joining the trial, said George.

UniQure NV, the Dutch biotechnology company that developed the first gene therapy approved in Europe, is also working on a treatment for hemophilia B and said in January that two patients on its treatment achieved 5.5 percent and 4.5 percent of normal.

Marrazzo said his goal is to clear the 5 percent bar by a wide margin -- “when you’re that close to the edge you run risks,” he said.

Both Spark and UniQure are still in early stages of development, and it will take years for the therapies to gain approval from the U.S. Food and Drug Administration and reach the market. Spark is also developing a gene therapy for hemophilia A, another form of the disorder that has a broader patient population. BioMarin Pharmaceutical Inc. presented early data in April showing that its hemophilia A treatment appeared to be working and safe.

Cost Question

Hemophilia B is a rare genetic disorder that affects about 4,000 males in the U.S. and 26,000 males worldwide, according to Spark. Patients currently are treated via infusions of factor IX self-administered twice a week to prevent bleeds. The treatment typically costs about $300,000 per year in the U.S., said Frick, from the National Hemophilia Foundation.

If these treatments were to come to market, “there are plenty of patients out there who would be really happy to use it as it would make a big difference in their lives,” Frick said. “The scary thing is cost -- how much will it cost and will insurance companies cover it?”

Since gene therapies are intended to be a one-time treatment that lasts a lifetime, they are expected to come with large price tags, potentially even hitting $1 million, Frick said. A representative for Spark declined to comment on a potential cost, noting that Pfizer will lead commercialization for the product, if approved.

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