What happened

Shares of uniQure (NASDAQ:QURE), a pioneer in gene therapy, jumped 171.2% in the first half of 2019, according to data from S&P Global Market Intelligence. Clinical trial results for a potential new hemophilia treatment have been pushing up the stock all year.

So what 

In February, uniQure announced positive results in three patients treated with AMT-061, a gene therapy that helps hemophilia B patients produce a blood clotting factor they can't produce on their own. Factor replacement therapy alone can cost $270,000 annually; add in an uncontrolled bleeding event with a hospital stay, and annual expenses can quickly pass $1 million.

Guy in a suit looking up at an upward sloping chart.

Image source: Getty Images.

Hemophilia is a rare disorder, but there's no shortage of experimental gene therapies trying to become the first, and no lack of deep-pocketed pharma companies that want to take a swing. Earlier this year, Roche (NASDAQOTH:RHHBY) agreed to acquire Spark Therapeutics (NASDAQ:ONCE) for $4.8 billion to get its hands on an experimental hemophilia gene therapy called SPK-8011, and there's a chance that uniQure could be the next biotech to receive a juicy buyout offer. 

Now what

Its next-generation hemophilia B candidate, AMT-061, is already in a pivotal study, and its predecessor AMT-060 continues to impress. All five patients treated with a single high dose of AMT-060 have remained free of routine factor-replacement therapy for three years, although the amount of clotting factor activity hasn't been nearly as strong as early results from AMT-061. Three patients treated with a single infusion of the new and improved version of AMT-061 showed clotting factor activity between 30% and 54% of what's considered normal at a 36-week observation.

A high dose of Sangamo's (NASDAQ:SGMO) experimental hemophilia A therapy, SB-525, helped three out of the four patients treated achieve normal clotting factor activity after 24 weeks. One even passed the normal threshold just seven weeks after treatment. Comparing data from SB-525 to AMT-061 is like comparing apples to oranges, but it's clear that uniQure's odds of launching a best-in-class gene therapy for hemophilia B are far from guaranteed.

While there are lots of programs aimed at hemophilia, uniQure has the only gene therapy candidate for the brain disorder Huntington's disease, AMT-130. The Food and Drug Administration cleared AMT-130 for clinical-stage testing that should begin soon.