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Fresh Off ASH Data, Spark Teams With Selecta to Boost Gene Therapies

Xconomy Boston — 

As a group of experimental gene therapies—potentially long-lasting, if not permanent treatments—for the blood disease hemophilia continue to creep through clinical testing, a few things have become clear. They’re helping patients produce meaningful amounts of the blood-clotting proteins they lack for increasingly long periods of time. But they also may not work for everybody. Spark Therapeutics, one of the leaders in hemophilia gene therapies, is taking a flier on a technology from Selecta Biosciences to help with that problem.

Spark (NASDAQ: ONCE), of Philadelphia, has struck a deal with Watertown, MA-based Selecta Biosciences (NASDAQ: SELB) to access a technology Selecta uses to try to suppress immune reactions that stifle a response to gene therapy. The two will use this technology on an experimental hemophilia A gene therapy from Spark, and possibly other gene therapy targets as well.

Selecta will get a small amount from Spark up front, just $10 million in cash and a commitment from Spark to buy $5 million in Selecta stock. Spark has agreed to make a like-sized payout again within 12 months, however, and Selecta could see much more in downstream milestone payments—as much as $435 million per program that advances—though its worth noting that the bulk of these payments, known as “biobucks,” often never materialize.

For Spark, the move is a low-cost way to deal with the neutralizing antibodies that some patients develop to gene therapies. This concern reared its head this weekend for Spark when it presented data on an experimental hemophilia B gene therapy, SPK-9001, at the American Society of Hematology’s annual meeting. While Spark revealed positive data in the latest incremental update to an ongoing early-stage trial of SPK-9001, two patients so far have developed immune responses to the gene therapy that have lowered the effectiveness of the treatment.

These types of immune reactions haven’t led to serious health problems for Spark or others testing hemophilia gene therapies, and they can be wiped out by a short course of immunosuppressive steroids. But they also mean that certain gene therapies may not work—or at least won’t work as well as they could—for some patients who develop neutralizing antibodies. It also means that patients who develop those antibodies won’t be eligible for a second dose if the gene therapy wears off. This phenomenon reduces the potential market for Spark, as well as other hemophilia B gene therapy developers like Dutch firm UniQure (NASDAQ: ONCE), which also presented its latest data at ASH this past weekend. But warding off immune responses could be useful in gene therapies for other diseases as well.

Selecta, which uses a nanoparticle technology to, among other things, help tell the immune system to call off an unwanted attack, might help address the problem. Spark CEO Jeff Marrazzo said in a statement that Selecta’s technology, for instance, might “prevent the formation of neutralizing antibodies” in the first place. The method, however, is very early in its development—it hasn’t been tested with a gene therapy in humans.

Spark said that the deal doesn’t impact SPK-9001, which it’s developing via a deal with Pfizer (NYSE: PFE), or the upcoming early-stage trial of SPK-8011 in hemophilia A.

Check out these stories for more on Selecta and gene therapy in hemophilia.