UniQure ($QURE) saw its stock slide 16% following a weekend in which data on its hemophilia B gene therapy AMT-060 went up against a rival readout from Spark Therapeutics ($ONCE). A single infusion of AMT-060 improved the hemophilia phenotype of all five patients in the uniQure study, but data on Factor IX (FIX) activity compared unfavorably to results presented by Spark.
Amsterdam, Netherlands-based uniQure gave the first five participants in its open-label Phase I/II trial a low dose of AMT-060 via a single infusion. After six months, the hemophilia phenotypes of the patients, which were classed as “severe” or “moderate-severe” prior to treatment, had all improved. Three of the participants had a mild phenotype, while the other two were classed as moderate. The mild status, which is given to patients with 5% or more of normal FIX expression, means patients are free from the need to receive prophylactic FIX infusions.
While the fact that AMT-060 delivered across-the-board improvements in phenotype and FIX activity, and freed all bar one of the patients from the burden of prophylactic infusions, is a solid result, the question of whether it will be good enough for the product to succeed is unanswered. Post-therapy FIX activity levels in uniQure’s study ranged from less than 2% to 6.3%. Spark, which is developing a rival hemophilia B gene therapy, achieved 27% to 35% FIX activity in its four-person study. In theory, higher FIX activity levels could reduce spontaneous bleeds and the need for on-demand FIX use.
The lack of long-term outcomes data means this and, by extension, discussions about which of the handful of hemophilia gene therapy and editing programs will win out, is little more than conjecture as it stands. That hasn’t helped uniQure’s stock though. The 16% drop following the hemophilia B readouts brought uniQure’s 12-month decline to 68% and its share price toward the historic lows last seen in 2014. Other gene therapy stocks have struggled over that period, too. Bluebird bio ($BLUE) is down 77% over the past year, while Spark has fallen 32% over the same period.
UniQure could arrest its decline later this year when it releases data from the second part of its Phase I/II trial, in which it has administered a higher dose of AMT-060 to five patients. The dose is four times higher than that given in the first stage of the study, raising the possibility that data on it will eradicate the efficacy questions that cropped up following this week’s readout.